Long-term results of double-door laminoplasty for cervical stenotic myelopathy

Comparison of Surgical Outcomes After Posterior Decompression by Junior or Senior Surgeons for Patients With Cervical Ossification of the Posterior Longitudinal Ligament: Results From Retrospective Multicenter Cohort Study

STUDY DESIGN

Retrospective multicenter study.

OBJECTIVES

To investigate surgical outcomes following posterior decompression for cervical ossification of the posterior longitudinal ligament (OPLL) when performed by board-certified spine (BCS) or non-BCS (NBCS) surgeons.

METHODS

We included 203 patients with cervical OPLL who were followed for a minimum of 1 year after surgery. Demographic information, medical history, and imaging findings were collected. Clinical outcomes were assessed preoperatively and at the final follow-up using the Japanese Orthopedic Association (JOA) score and the visual analog scale (VAS) for the neck. We compared outcomes between BCS surgeons, who must meet several requirements, including experience in more than 300 spinal surgeries, and NBCS surgeons.

RESULTS

BCS surgeons performed 124 out of 203 cases, while NBCS surgeons were primary in 79 cases, with 73.4% were directly supervised by a BCS surgeon. There was no statistically significant difference in surgical duration, estimated blood loss, and perioperative complication rates between the BCS and NBCS groups. Moreover, no statistically significant group differences were observed in each position of the C2-7 angle and cervical range of motion at preoperation and the final follow-up. Preoperative and final follow-up JOA scores, VAS for the neck, and JOA score recovery rate were comparable between the two groups.

CONCLUSIONS

Surgical outcomes, including functional recovery, complication rates, and cervical dynamics, were comparable between the BCS and NBCS groups. Consequently, posterior decompression for cervical OPLL is considered safe and effective when conducted by junior surgeons who have undergone training and supervision by experienced spine surgeons.

Accuracy of Realigned K-line for Predicting Surgical Outcomes After Laminoplasty in Patients With Degenerative Cervical Myelopathy

STUDY DESIGN

A prospective cohort study.

OBJECTIVES

To report a new index, the realigned K-line, for predicting surgical outcomes after laminoplasty in patients with degenerative cervical myelopathy (DCM).

METHODS

One hundred twenty-eight patients with DCM undergoing laminoplasty were enrolled from January 2018 to April 2021 in our department. A realigned K-line was defined as the line connecting the midpoints of the spinal cord between C2 and C7 on realigned T1-weighted magnetic resonance imaging. The minimum interval between the anterior compression factors of the spinal cord and the realigned K-line (INTrea), and the modified K-line (INTmod) were measured. A logistic regression analysis was performed to identify factors associated with unsatisfactory surgical outcomes. The receiver operating characteristic (ROC) curve and the area under the curve (AUC) was applied to evaluate the reliability of the multivariate logistic regression model.

RESULTS

Univariate analysis showed that the score for the bladder function section of the Japanese Orthopedic Association Cervical Myelopathy Evaluation Questionnaire, numeric rating scale scores for arm pain, and INTrea might be related to the Japanese Orthopaedic Association (JOA) recovery rate (RR) not achieving the minimal clinically important difference (MCID) (P < .05). Only INTrea (odds ratio = .744, P < .05) was an independent preoperative factor related to the JOA RR not achieving the MCID (area under the curve, .743). A cutoff of 5.0 mm for INTrea had an accuracy of 71.9% and specificity of 80.3% for predicting the JOA RR not achieving the MCID.

CONCLUSIONS

INTrea is an independent preoperative risk factor related to the JOA RR not achieving the MCID in patients with DCM. A cutoff point of 5.0 mm is most appropriate for alerting spine surgeons to a high likelihood of the JOA RR not achieving the MCID.

Effectiveness of additional C2 decompression of the cervical spinal canal after cervical laminoplasty: a retrospective cohort study

PURPOSE

This study aimed to assess the effects of additional C2 decompression of the cervical spinal canal on the postoperative outcomes after cervical laminoplasty in patients with cervical stenosis caused by ossification of the posterior longitudinal ligament (OPLL).

MATERIALS AND METHODS

This retrospective cohort study included patients with cervical stenosis due to OPLL and treated between April 2014 and December 2015. The patients who underwent C2-7 (additional C2 decompression) and C3-7 posterior decompression were compared using the Japanese Orthopedic Association (JOA) scores, visual analog scale (VAS) scores, axial symptom scores, and intervals between the posterior margin of the vertebral body and the K-line.

RESULTS

There were 36 and 24 patients in the additional C2 decompression and control groups, respectively. The JOA scores were higher in the additional C2 decompression group than the controls at 1 and 3 years (p < 0.05). Upper extremity motor function after the operation and at 1 and 3 years and lower extremity motor function after operation were improved in the additional C2 decompression group (all p < 0.05 vs. controls). VAS scores were lower in the additional C2 decompression group than controls at 1 year (p < 0.05). Axial symptom scores in the additional C2 decompression group were decreased postoperatively but increased at 1 and 3 years (p < 0.05 vs. controls). Finally, the posterior shift of the K-line in the additional C2 decompression group was significant (from 0.98 to 1.68 cm, p < 0.05).

CONCLUSIONS

Additional C2 decompression might improve the effectiveness of cervical laminoplasty in patients with cervical stenosis caused by OPLL.

Change of cervical flexion range of motion influences postoperative sagittal alignment of the cervical spine after laminoplasty

OBJECTIVE

The relationships between preoperative cervical spine range of motion (ROM) and postoperative cervical sagittal alignment (CSA), and clinical outcomes after laminoplasty (LMP) have been widely studied. However, the impact of ROM changes on postoperative CSA and clinical outcomes after LMP remains unclear. Herein, patients with cervical spondylotic myelopathy (CSM) were retrospectively analyzed to explore the association between postoperative cervical ROM changes and CSA and surgical outcomes.

METHODS

Patients who underwent cervical LMP at our hospital between January 2019 to June 2022 were retrospectively reviewed. CSA parameters were measured before the surgery and at the final follow-up. Loss of cervical lordosis (LCL) was defined as preoperative cervical lordosis (CL) - postoperative CL. An increase in the cervical sagittal vertical axis (I-cSVA) was defined as postoperative cervical sagittal vertical axis (cSVA) - preoperative cSVA. We defined the changes in cervical flexion range of motion (△Flex ROM, preoperative Flex ROM minus postoperative Flex ROM) > 10° as L- Flex ROM group, and △Flex ROM ≤ 10° as S- Flex ROM group. Japanese Orthopedic Association (JOA) score and visual analog score (VAS) were used to assess the surgical outcomes.

RESULTS

The study comprised 74 patients and the average follow-up period was 31.83 months. CL, total ROM, and Flex ROM decreased and cSVA increased after cervical LMP. LCL and I-cSVA were positively correlated with △Flex. Multiple linear regression analysis showed that a decrease in the Flex ROM was a risk factor for LCL and I-cSVA after LMP. LCL and I-cSVA were higher in the L-Flex ROM group than in the S-Flex ROM group. Postoperative JOA and the JOA recovery rate were worse in the L-Flex ROM group than in the S-Flex ROM group.

CONCLUSIONS

Cervical total and Flex ROM decreased after cervical LMP. The reduction of Flex ROM was associated with LCL and I-cSVA after surgery. The preservation of cervical Flex ROM helps maintain CSA after LMP. Therefore, more attention should be paid to maintaining cervical ROM to obtain good CSA and surgical effects after cervical LMP.

Plate-only open-door laminoplasty is associated with durable, significantly improved clinical outcomes and a very low reoperation rate for progressive spondylosis or adjacent segment disease: average 8-year follow-up

BACKGROUND CONTEXT

Multilevel cervical myelopathy is a common cause of spinal cord dysfunction in adults. Surgical intervention via laminoplasty can provide satisfactory clinical outcomes by expansive decompression of the spinal cord. Traditional suture or bone graft techniques have been associated with insufficient fixation, leading to premature closure and subsequent neurological deterioration. In contrast, plated laminoplasty has been shown to provide stable fixation to maintain canal enlargement, but longer-term outcomes are lacking.

PURPOSE

To evaluate longer-term clinical outcomes and reoperations associated with plate-only open-door laminoplasty.

STUDY DESIGN

Retrospective review of prospectively collected data.

PATIENT SAMPLE

Postoperative patients who underwent plate-only open door laminoplasty with minimum 5-year follow up.

OUTCOME MEASURES

modified Japanese Orthopaedic Association (mJOA) score, Neck Disability Index (NDI), and 12-item Short Form Health Survey (SF-12).

METHODS

All patients at a single academic institution who underwent plate-only open-door cervical laminoplasty from 9/1/2006 to 9/1/2016 were identified to ensure minimum 5 year follow up. Clinical outcomes included the modified Japanese Orthopaedic Association (mJOA) score, the Neck Disability Index (NDI), and the 12-item Short Form Health Survey (SF-12). The occurrence of any repeat operations on the cervical spine was evaluated, as well as its cause. The study team attempted to contact all eligible patients to achieve at least 5 years postoperative follow-up. Pairwise t tests were performed to compare clinical outcomes at preoperative, 6 months, 1-year, and final postoperative follow-up with an α level of 0.05.

RESULTS

A total of 774 met the initial inclusion criteria, of which 157 were included in the study (20.3%). Most common reasons for exclusion included inability to reach after 3 attempts (49.48%), inactive phone numbers (20.28%), and patient declining (3.49%). Included patients had an average age of 60.66±10.63 and an average follow-up time of 8.37±2.57 years (minimum 5 years). mJOA scores (preoperative 11.59±2.16) improved significantly at 6-months (14.57±2.07, p<.001), 1-year (15.19±1.95, p<.001), and final follow-up (14.59±2.63, p<.001). NDI (preoperative 33.89±18.54) improved significantly at 6 months (27.89±19.72, p=.03), 1-year (25.96±19.79, p=.01) and final follow-up (17.88±17.17, p<.001). SF-12 MCS (preoperative 44.73) improved significantly at 6 months (52.01, p=.001), 1-year (51.62, p=.008), and final follow-up (52.32, p<.001). No patient underwent reoperations for plate failure or canal closure with recurrent stenosis. Reoperations for progressive spondylosis during the follow up period were rare and occurred in only three patients for new onset radiculopathy (1.9%) and two patients for myelopathy (1.3%) at an average of 3.2 years postoperative. There were no reoperations performed for adjacent segment disease.

CONCLUSIONS

At a minimum of 5 years and an average of more than 8 years postoperative, laminoplasty was associated with significant and sustained improvements in mJOA, NDI, and SF-12 MCS. Importantly, no patients underwent revision surgery for plate failure or recurrent canal closure. Reoperations for new onset radiculopathy and myelopathy were also very rare over the 8-year average follow-up period, with no reoperations for adjacent segment disease. Plate-only laminoplasty is a durable means of treating multilevel myelopathy with excellent longer-term outcomes and a very low risk of reoperation, either for premature closure or the inevitable spondylotic changes that occur over time in patients with similar baseline characteristics to the study population.

Relationship between hinge fracture and postoperative axial symptoms after cervical laminoplasty

OBJECTIVE

To identify the clinical characteristics of fractured hinges after open-door cervical laminoplasty for cervical canal stenosis and explore the relationship between hinge fractures and axial symptoms.

METHODS

This was a retrospective study of patients with cervical myelopathy who underwent open-door laminoplasty between November 2014 and November 2016 at the Affiliated Hospital of Qingdao University. Cervical CT scans were performed after surgery and the Takeuchi criteria were applied to evaluate the postoperative axial symptoms.

RESULTS

Of 223 opened laminae in 67 patients, 67 laminae (30.0%) in 30 patients (44.8%) showed fracture. The frequency of hinge fractures was higher at C6 (53.7%). Forty-nine fractured laminae (73.13%) were non-displaced and 18 were displaced. At 3 months, 33 fractured laminae (49.3%) showed bony union on CT, and union rates were 86.6% and 91.0% at 6 and 12 months, respectively, indicating that the union rate was lower for displaced fractures than for non-displaced fractures. Among the 67 patients, 14 had axial symptoms: three of 37 (8.1%) patients without hinge fractures and 11 of 30 (36.7%) patients with hinge fractures. One year later, the hinge fractures were healed in 24/30 patients. Among the six unhealed patients, five still suffered from axial symptoms. The frequency of axial symptoms was higher in the patients with three or more hinge fractures (66.7%) than in the patients with only one (16.7%) or two (46.7%) hinge fractures.

CONCLUSIONS

Patients with hinge fractures may have an increased risk for axial symptoms after open-door cervical laminoplasty. The frequency of axial symptoms decreases with fracture healing.

Time course of symptomatic improvement after open-door laminoplasty for cervical spondylotic myelopathy

BACKGROUND

Postoperative outcomes following cervical spondylotic myelopathy (CSM) are excellent overall, but there are few prospective studies using patient-reported outcome measures that have explored how long improvement can be expected after surgery. The aim of this prospective study was to investigate from when and until when symptoms improve after open-door laminoplasty in patients with CSM and the factors that affect surgical outcomes.

METHODS

The subjects were 115 CSM patients who underwent laminoplasty. The Japanese Orthopaedic Association Cervical Myelopathy Evaluation Questionnaire (JOACMEQ) was used for longitudinal evaluation, and surveys on cervical spine function, upper extremity function, lower extremity function, bladder function, and quality of life were conducted before surgery and at 3, 6, 12, 18, and 24 months after surgery. The patients were classified into 'effective' and 'ineffective' groups based on the points obtained for each domain, and the factors affecting the outcome of surgery were examined by multivariate analysis.

RESULTS

JOACMEQ scores improved significantly at 3 months postoperatively compared to preoperatively for all four domains except cervical spine function, but there was no significant improvement after 3 months postoperatively. Multivariate analysis showed that the preoperative score (cervical spine function and upper extremity function) and the points obtained at 3 months postoperatively (upper and lower extremity function, bladder function, and quality of life) were the factors associated with membership of the effective group at 24 months postoperatively.

CONCLUSIONS

Although upper and lower extremity function, bladder function, and quality of life domains improved in the relatively early postoperative period, improvement after 3 months postoperatively was limited. The results suggest that the preoperative score and the superiority of the improvement obtained up to 3 months after surgery may be indicators of postoperative outcomes, and this may provide new insights into the selection of surgical indications and patient explanations.

Impact of C3 laminectomy on cervical sagittal alignment in cervical laminoplasty: a prospective, randomized controlled trial comparing clinical and radiological outcomes between C3 laminectomy with C4-C6 laminoplasty and C3-C6 laminoplasty

BACKGROUND CONTEXT

C3 laminectomy in cervical laminoplasty is a modified laminoplasty technique that can preserve the semispinalis cervicis muscle attached to the C2 spinous process. Several previous studies have shown that this technique can lead to better outcomes of postoperative axial neck pain and C2-C3 range of motion (ROM) than conventional cervical laminoplasty. However, there is still a lack of understanding of total and proportional postoperative cervical sagittal alignment outcomes.

PURPOSE

To assess the effects of C3 laminectomy in cervical laminoplasty on postoperative cervical alignment and clinical outcomes.

DESIGN

A single-center, patient-blinded, randomized controlled trial.

PATIENT SAMPLE

We included consecutive 126 patients diagnosed with cervical spondylotic myelopathy (CSM) or ossification of posterior longitudinal ligament (OPLL) who were scheduled for cervical laminoplasty from March 2017 to January 2020.

OUTCOME MEASURES

The primary outcome measures were C2-C7 Cobb angle (CA) and neck disability index (NDI). Secondary outcomes measures included other clinical outcomes and radiographic parameters including segmental Cobb angle and presence of C2-C3 interlaminar fusion.

METHODS

Patients were randomly allocated to either the C3 laminectomy with C4-C6 laminoplasty group (LN group) or the C3-C6 laminoplasty group (LP group) at a 1:1 ratio. Laminoplasty was performed using a unilateral open-door technique and stabilized with titanium mini plates. A linear mixed model analysis was employed to examine the longitudinal data from postoperative 1-year through 3-year. Additional analysis between three types of cervical sagittal alignment morphology was done.

RESULTS

Among 122 patients who were randomly allocated to one of two groups (LN group, n=61; LP group, n=61), modified intent-to-treat analysis was done for 109 patients (LN group, n=51, LP group, n=58) who had available at least a year of postoperative data. Postoperative C2-C7 CA was not significantly different between the two groups. However, NDI was significantly different between the two groups (12.8±1.0 in the LN group vs 8.6±1.0 in LP group, p=.005), which exceeded the minimum clinically important difference (MCID). The postoperative C2-C3 CA was significantly greater in the LN group (7.1±0.5° in LN group vs 3.2±0.5° in LP group, p<.001) while C4-C7 CA was significantly smaller in the LN group (3.9±0.8° in LN group vs 7.7±0.7° in LP group, p<.001) with greater cSVA in the LN group (31.6±1.4 mm in LN group vs 25.5±1.3 mm in LP group at postoperative 3-year, p=.002). Postoperative Euro-Quality of Life-5 Dimension (EQ-5D), numerical rating scores for neck pain (NRS-N) were significantly better in the LP group than in the LN group (all p<.05) and only EQ-5D surpassed the MCID. The C2-C3 fusion rate was significantly different between the LN group (9.8%) and the LP group (44.8%) (p<.001). The LN group showed a higher prevalence of a specific cervical alignment morphology characterized by a sigmoid shape with proximal lordosis and distal kyphosis (S curve). This S curve demonstrated significantly unfavorable outcomes across multiple outcome variables.

CONCLUSION

The impact of C3 laminectomy in cervical laminoplasty on postoperative kyphosis among patients with CSM or OPLL did not significantly differ from that of C3-C6 laminoplasty. However, C3 laminectomy in cervical laminoplasty might result in an unfavorable clinical outcome with an unbalanced cervical sagittal alignment characterized by a sigmoid shape with proximal lordosis and distal kyphosis.

Trends in cervical laminoplasty and 30-day postoperative complications: 10-year results from a retrospective, multi-institutional study of 1095 patients

PURPOSE

This study aimed to investigate the recent 10-year trends in cervical laminoplasty and 30-day postoperative complications.

METHODS

This retrospective multi-institutional cohort study enrolled patients who underwent laminoplasty for cervical spondylotic myelopathy (CSM) or ossification of the posterior longitudinal ligament. The primary outcome was the occurrence of all-cause 30-day complications. Trends were investigated and compared in the early (2008-2012) and late (2013-2017) periods.

RESULTS

Among 1095 patients (mean age, 66 years; 762 [70%] male), 542 and 553 patients were treated in the early and late periods, respectively. In the late period, patients were older at surgery (65 years vs. 68 years), there were more males (66% vs. 73%), and open-door laminoplasty (50% vs. 69%) was the preferred procedure, while %CSM (77% vs. 78%) and the perioperative JOA scores were similar to the early period. During the study period, the rate of preservation of the posterior muscle-ligament complex attached to the C2/C7-spinous process (C2, 89% vs. 93%; C7, 62% vs. 85%) increased and the number of laminoplasty levels (3.7 vs. 3.1) decreased. While the 30-day complication rate remained stable (3.9% vs. 3.4%), C5 palsy tended to decrease (2.4% vs. 0.9%, P = 0.059); superficial SSI increased significantly (0% vs. 1.3%, P = 0.015), while the decreased incidence of deep SSI did not reach statistical significance (0.6% vs. 0.2%).

CONCLUSIONS

From 2008 to 2017, there were trends toward increasing age at surgery and surgeons' preference for refined open-door laminoplasty. The 30-day complication rate remained stable, but the C5 palsy rate halved.

Quantitatively biomechanical response analysis of posterior musculature reconstruction in cervical single-door laminoplasty

BACKGROUND AND OBJECTIVE

The current trend of laminoplasty is developing toward the goal of muscle preservation and minimum tissue damage. Given this, muscle-preserving techniques in cervical single-door laminoplasty have been modified with protecting the spinous processes at the sites of C2 and/or C7 muscle attachment and reconstruct the posterior musculature in recent years. To date, no study has reported the effect of preserving the posterior musculature during the reconstruction. The purpose of this study is to quantitatively evaluate the biomechanical effect of multiple modified single-door laminoplasty procedures for restoring stability and reducing response level on the cervical spine.

METHODS

Different cervical laminoplasty models were established for evaluating kinematics and response simulations based on a detailed finite element (FE) head-neck active model (HNAM), including ① C3 - C7 laminoplasty (LP_C37), ② C3 - C6 laminoplasty with C7 spinous process preservation (LP_C36), ③ C3 laminectomy hybrid decompression with C4 - C6 laminoplasty (LT_C3 + LP_C46) and ④ C3 - C7 laminoplasty with unilateral musculature preservation (LP_C37 + UMP). The laminoplasty model was validated by the global range of motion (ROM) and percentage changes relative to the intact state. The C2 - T1 ROM, axial muscle tensile force, and stress/strain levels of functional spinal units were compared among the different laminoplasty groups. The obtained effects were further analysed by comparison with a review of clinical data on cervical laminoplasty scenarios.

RESULTS

Analysis of the locations of concentration of muscle load showed that the C2 muscle attachment sustained more tensile loading than the C7 muscle attachment, primarily in flexion-extension (FE) and in lateral bending (LB) and axial rotation (AR), respectively. Simulated results further quantified that LP_C36 primarily produced 10% decreases in LB and AR modes relative to LP_C37. Compared with LP_C36, LT_C3 + LP_C46 resulted in approximately 30% decreases in FE motion; LP C37 + UMP also showed a similar trend. Additionally, when compared to LP_C37, LT_C3 + LP_C46 and LP C37 + UMP reduced the peak stress level at the intervertebral disc by at most 2-fold as well as the peak strain level of the facet joint capsule by 2-3-fold. All these findings were well correlated with the result of clinical studies comparing modified laminoplasty and classic laminoplasty.

CONCLUSIONS

Modified muscle-preserving laminoplasty is superior to classic laminoplasty due to the biomechanical effect of the posterior musculature reconstruction, with a retained postoperative ROM and loading response levels of the functional spinal units. More motion-sparing is beneficial for increasing cervical stability, which probably accelerates the recovery of postoperative neck movement and reduces the risk of the complication for eventual kyphosis and axial pain. Surgeons are encouraged to make every effort to preserve the attachment of the C2 whenever feasible in laminoplasty.

Changes of improvement in upper limb function predict surgical outcome after laminoplasty in 1 year in patients with cervical spondylotic myelopathy: a retrospective study

BACKGROUND

Cervical spondylotic myelopathy preoperative prognostic factors include age, preoperative severity, and disease duration. However, there are no reports on the relationship between changes in physical function during hospitalization and postoperative course, and in recent years, the length of hospital stay has shortened. We aimed to investigate whether changes in physical function during hospitalization can predict the postoperative outcome.

METHODS

We recruited 104 patients who underwent laminoplasty for cervical spondylotic myelopathy by the same surgeon. Physical functions, including Simple Test for Evaluating Hand Function (STEF), grip strength, timed up and go test, 10-m walk, and time to stand on one leg, were assessed at admission and discharge. Patients with the Japanese Orthopaedic Association (JOA) score improvement rate of 50% or more were defined as the improved group. Decision tree analysis was investigated factor for identifying improvement in the JOA score. According to this analysis, we divided into two groups using age. Then, we conducted a logistic regression analysis to identify factors that improve the JOA score.

RESULTS

The improved and non-improved groups had 31 and 73 patients, respectively. The improved group was younger (p = 0.003) and had better improved Δgrip strength (p = 0.001) and ΔSTEF (p < .0007). Age was significantly positively correlated with disease duration (r = 0.4881, p =  < .001). Disease duration exhibited a significant negative correlation with the JOA score improvement rate (r = - 0.2127, p = 0.031). Based on the decision tree analysis results, age was the first branching variable, with 15% of patients ≥ 67 years showing JOA score improvement. This was followed by ΔSTEF as the second branching factor. ΔSTEF was selected as the factor associated with JOA improvement in patients ≥ 67 years (odds ratio (OR) 0.95, 95% confidence interval (CI) 0.90-0.99, p = .047); in patients < 67 years, Δgrip strength was identified (OR 0.53, CI 0.33‒0.85, p = .0086).

CONCLUSIONS

In the improved group, upper limb function improved more than lower limb function from the early postoperative period. Upper limb function changes during hospitalization were associated with outcomes one year postoperatively. Improvement factors in upper extremity function differed by age, with changes in grip strength in patients < 67 years and STEF in patients ≥ 67 years, reflecting the outcome at one year postoperatively.

Comparison of clinical outcomes of modified laminoplasty with preservation of muscle group inserted into C2 and C7 spinous processes versus conventional C3-C7 laminoplasty: a prospective, randomized, controlled, noninferiority trial

BACKGROUND

The efficacy and noninferior of performing modified double-door laminoplasty (MDDL) (C4-C6 laminoplasty plus C3 laminectomy, alongside a dome-like resection of the inferior part of the C2 lamina and the superior part of the C7 lamina) in patients with multilevel cervical spondylotic myelopathy (MCSM) is equivocal. A randomized, controlled trial is warranted.

OBJECTIVE

The objective was to evaluate the clinical efficacy and noninferior of MDDL compared with traditional C3-C7 double-door laminoplasty.

STUDY DESIGN

A single-blind, randomized, controlled trial.

METHODS

A single-blind, randomized, controlled trial was conducted in which patients who with MCSM with greater than or equal to 3 levels of spinal cord compression from the C3 to the C7 vertebral levels were enrolled and assigned to undergo either MDDL group or conventional double-door laminoplasty (CDDL) group in a 1:1 ratio. The primary outcome was the change in the Japanese Orthopedic Association score from baseline to 2-year follow-up. The secondary outcomes included changes in the Neck Disability Index (NDI) score, the Visual Analog Scale (VAS) for neck pain, and imaging parameters. Operative complications were also collected and reported. The outcome measures were compared between the groups at 3 months, 1 year, or 2 years after surgery.

RESULTS

A total of 96 patients (mean age 67 years, 39.8% women) underwent randomization. Of these patients, 93 completed 3-month follow-up, 79 completed 1-year follow-up, and 66 completed 2-year follow-up. The changes in the Japanese Orthopedic Association score did not differ significantly between the study groups at the three time points after surgery. With respect to amelioration of neck pain and disability related to neck pain, patients in the MDDL group had a significantly greater decrease in the VAS and NDI component summary score than did those in the CDDL group at 1-year (VAS: -2.5 vs. -3.2, difference -0.7, 95% CI -1.1 to -0.2, P =0.0035; NDI: -13.6 vs. -19.3, difference -5.7, 95% CI -10.3 to -1.1, P =0.0159) and 2-years (VAS: -2.1 vs. -2.9, difference -0.8, 95% CI -1.4 to -0.2, P =0.0109; NDI: -9.3 vs. -16.0, difference -6.7, 95% CI -11.9 to -1.5, P =0.0127). The changes in the range of motion (ROM), the C2-C7 Cobb angle, and the cervical sagittal vertical axis in the MDDL group were significantly less than those in the CDDL group (ROM: -9.2±6.4 vs. -5.0±6.0, P =0.0079; C2-C7 Cobb angle: -7.9±7.8 vs. -4.1±6.2, P =0.0345; cervical sagittal vertical axis: 0.6±0.9 vs. 0.2±0.6, P =0.0233). The MDDL group had less blood loss (428.1 vs. 349.1, P =0.0175) and a lower rate of axial symptoms (27.3 vs. 6.1%, P =0.0475) than the CDDL group.

CONCLUSIONS

Among patients with MCSM, the MDDL produced similar cervical cord decompression compared with the conventional C3-C7 double-door laminoplasty. The modified laminoplasty was associated with meaningful improvement in amelioration of neck discomfort, maintaining a better cervical ROM and sagittal alignment, decreasing blood loss, and reducing the incidence of axial symptoms.

Neurological Survivorship Following Surgery for Degenerative Cervical Myelopathy: A Longitudinal Study on 195 Patients

BACKGROUND

Long-term data on postoperative neurological survivorship for patients with degenerative cervical myelopathy (DCM) undergoing decompressive surgery are limited. The purposes of this study were to assess neurological survivorship after primary decompressive surgery for DCM and to identify predictors for postoperative deterioration.

METHODS

A longitudinal clinical data set containing surgical details, medical comorbidities, and radiographic features was assembled for 195 patients who underwent a surgical procedure for DCM between 1999 and 2020, with a mean period of observation of 75.9 months. Kaplan-Meier curves were plotted, and a log-rank test was performed for the univariate analysis of factors related to neurological failure. Lasso regression facilitated the variable selection in the Cox proportional hazards model for multivariate analysis.

RESULTS

The overall neurological survivorship was 89.3% at 5 years and 77.3% at 10 years. Cox multivariate analysis following lasso regression identified elevated hazard ratios (HRs) for suture laminoplasty (HR, 4.76; p < 0.001), renal failure (HR, 4.43; p = 0.013), T2 hyperintensity (HR, 3.34; p = 0.05), and ossification of the posterior longitudinal ligament (OPLL) (HR, 2.32; p = 0.032). Subgroup analysis among subjects with OPLL demonstrated that the neurological failure rate was significantly higher in the absence of fusion (77.8% compared with 26.3%; p = 0.019).

CONCLUSIONS

Overall, patients who underwent a surgical procedure for DCM exhibited an extended period with neurological improvement. Cervical fusion was indicated in OPLL to reduce neurological failure. Our findings on predictors for early deterioration facilitate case selection, prognostication, and counseling as the volume of primary cervical spine surgeries and reoperations increases globally.

LEVEL OF EVIDENCE

Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Initial clinical experiences of the muscle-preserving double door cervical laminoplasty with adjustable mini plates

Shirashi's double door laminoplasty method was a popular decompression procedure for cervical myelopathy. In this paper, we introduced a modified double door laminoplasty based on Shirashi's method with preliminary results. This study retrospectively analyzed 22 patients who underwent modified double door laminoplasty. During procedure, a single segment of the unilateral lamina was separated from the cervical semispinalis muscle and the multifidus muscle space for the preparation of lamina groove. A self-developed mini titanium plate was used to fix the inner side of the spinous process to complete the fixation after open-door process. The VAS, JOA scores and QoL scale were recorded for pain assessment, neurological and functional recovery. The overall curvature and range of motion of C2-C7 were measured with x-ray images. Changes in sagittal diameter of spinal canal were measured by CT scans. MRI was used to measure the cross-sectional area of cervical paravertebral muscles. All 22 patients successfully recovered with this procedure. The mean operation time, blood loss and follow-up durations were 117 ± 25 min, 149 ± 32 ml and 16.1 ± 3.6 months respectively. The preoperative, 3-month postoperative and 12-month postoperative JOA scores were 9.35 ± 3.25, 13.74 ± 4.86 and 15.73 ± 5.19 respectively. with improvement rates of 57.4% and 83.4%. Mean VAS scores before, 3 months after and 12 months after surgery were 1.81 ± 0.79, 2.82 ± 1.56 and 2.18 ± 1.34 respectively. The C2-7 lordotic angle and overall range of motion shows no statistical difference preoperatively and 12 post-surgery. The average sagittal diameter of the cervical spinal canal was enlarged from 9.15 ± 1.55 mm to 14.25 ± 1.46 mm. The average area of cervical paravertebral volume measured preoperatively and 3 months post operation was 84% of pre-operative value respectively. This value was improved to 93% of the preoperative value at 12 months post-surgery. This paper introduced initial experience on a modified posterior cervical double-door laminoplasty that was based on Shirashi's method, featuring creating bilateral laminar grooves on both sides and fixing central gap with self-developed mini plates. This procedure prevented obvious axial symptoms and improved patients' quality of life, which provided a baseline for further research with larger cohorts.

Change in Physical and Mental Quality-of-Life between the Short- and Mid-Term Periods after Cervical Laminoplasty for Cervical Spondylotic Myelopathy: A Retrospective Cohort Study with Minimum 5 Years Follow-up

The mid-term surgical outcomes of cervical spondylotic myelopathy (CSM), evaluated using the cervical Japanese Orthopedic Association (cJOA) score, are reported to be satisfactory. However, there remains room for improvement in quality-of-life (QOL), especially after short-term follow-up. We aimed to demonstrate changes in mental and physical QOL between short- and mid-term follow-ups and determine the predictive factors for deterioration of QOL. In this retrospective cohort study, 80 consecutive patients underwent laminoplasty for CSM. The outcome measures were Short Form-36 Physical Component Summary (PCS), Mental Component Summary (MCS), and cJOA scores. PCS and MCS scores were compared at the 2- and 5-year postoperative time points. Additionally, a multivariate logistic regression model was used to identify the predictive factors for deterioration. Significant factors in the logistic regression analysis were analyzed using receiver-operating characteristic curves. The results showed that MCS scores did not deteriorate after 2 years postoperatively (p = 0.912). Meanwhile, PCS significantly declined between 2 and 5 years postoperatively (p = 0.008). cJOA scores at 2 years postoperatively were significantly associated with PCS deterioration at 2-year follow-up. In conclusion, only physical QOL might show deterioration after short-term follow-up. Such deterioration is likely in patients with a cJOA score <13.0 at 2 years postoperatively.

Different standing postures are the influencing factors for the efficacy of laminoplasty in the treatment of K-Line (-) patients with ossification of the posterior longitudinal ligament

OBJECTIVE

To investigate the relationship between different standing postures and surgical outcomes of K-Line (-) ossification of the posterior longitudinal ligament (OPLL) patients after laminoplasty with a titanium basket. There is a lack of data evaluating the relationship between the postoperative satisfaction of K-Line (-) patients and their standing postures.

METHODS

OPLL patients enrolled in the study were divided into a K-Line (+) group (Group A) and a K-Line (- group (Group B) in natural and relaxed standing positions. We compared the postoperative outcomes after cervical laminoplasty with titanium basket surgery using the Japanese Orthopaedic Association score (JOA), recovery rate and the degree of improvement in the six JOA score items. The degree of satisfaction with the outcome was assessed at the 1-year follow-up using a 7-point numerical rating scale.

RESULTS

A total of 34 K-Line (+) patients with OPLL (age 61.9 ± 2.9 years) in Group A and 40 K-Line (-)patients with OPLL (age 60.4 ± 3.5 years) in Group B in natural and relaxed standing positions were recruited. In Group A, the mean preoperative and postoperative JOA scores were 10.1 ± 1.4 and 13.1 ± 0.8 points, respectively, and in Group B, the mean preoperative and postoperative JOA scores were 9.7 ± 1.3 and 11.1 ± 0.9 points, respectively. A significant improvement in the JOA score was seen in both groups postoperatively, but the recovery rate of the patients' JOA scores was significantly lower in Group B. In Group A, significant improvements were seen in all JOA score items, but in Group B, improvements were seen only in upper- and lower-extremity sensory functions.

CONCLUSION

Different standing postures are risk factors in the treatment of K-Line (-) patients, and therefore, natural and relaxed standing positions should be given more attention before devising the surgical plan.

Comparison of surgical outcomes of posterior surgeries between cervical spondylotic myelopathy and ossification of the posterior longitudinal ligament

STUDY DESIGN

Retrospective multicenter study.

OBJECTIVE

To compare the surgical outcomes and complications of posterior decompression between individuals with cervical spondylotic myelopathy (CSM) and those with ossification of the posterior longitudinal ligament (OPLL).

SETTING

Seventeen medical institutions in Japan.

METHODS

This study included 814 individuals with CSM (n = 636) and OPLL (n = 178) who underwent posterior decompression. Propensity score matching of the baseline characteristics was performed to compare surgical outcomes and perioperative complications between the CSM and OPLL groups.

RESULTS

Before propensity score matching, the OPLL group had higher percentage of male individuals, body mass index, and number of stenosis levels and longer duration of symptoms (P < 0.01, P < 0.01, P < 0.01, and P < 0.01, respectively). After matching, the baseline characteristics were comparable between the CSM (n = 98) and OPLL (n = 98) groups. The postoperative Japanese Orthopaedic Association (JOA) scores, preoperative-to-postoperative changes in the JOA scores, and JOA score recovery rates were not significantly different between the groups (P = 0.42, P = 0.47, and P = 0.09, respectively). The postoperative visual analog scale (VAS) score for neck pain and preoperative-to-postoperative changes in the VAS score for neck pain were not significantly different between the groups (P = 0.25 and P = 0.50, respectively). The incidence of perioperative complications was comparable between groups.

CONCLUSION

Neurological improvement and complication rates after surgery were comparable between individuals with CSM and those with OPLL, suggesting similar effectiveness and safety of posterior decompression for both conditions.

Cervical foraminal stenosis as a risk factor for cervical kyphosis following cervical laminoplasty

BACKGROUND CONTEXT

Cervical laminoplasty (CLP) is an effective spinal cord decompression method for patients with cervical myelopathy. However, cervical kyphosis after CLP may cause insufficient decompression of the spinal cord. Thus, prevention of cervical kyphosis after CLP and identification of its risk factors are essential.

PURPOSE

This study aimed to investigate the relationship between preoperative cervical foraminal stenosis and kyphotic changes after CLP.

STUDY DESIGN

A retrospective study.

PATIENT SAMPLE

We reviewed 108 patients who underwent CLP for cervical myelopathy between May 2014 and May 2019 and who were followed up for at least 24 months.

OUTCOME MEASURES

For clinical assessments, neck pain, arm pain, neck disability index, Japanese Orthopedic Association scores, EuroQol 5-Dimension, and subjective improvement rate reported by the patients were evaluated. For radiologic parameters, C2-7 Cobb lordotic angle (CLA), C2-7 sagittal vertical axis, T1 slope (TS), TS minus CLA (TS-CLA), and cervical range of motion were assessed preoperatively and postoperatively for 24 months. Cervical foraminal stenosis was evaluated by magnetic resonance imaging and computed tomography.

METHODS

The study population was divided into the kyphosis group (n = 25 patients) and the lordosis group (n = 83 patients) according to the CLA at 24 months postoperatively. Preoperative risk factors related to postoperative kyphosis were analyzed. Statistical analyses were performed using independent two-sample t test, Chi-square test, logistic regression analysis, and linear mixed model.

RESULTS

Preoperative foraminal stenosis, CLA, TS, and TS-CLA were significantly different between the kyphosis and lordosis groups. In multivariate logistic regression analysis, foraminal stenosis (odds ratio [OR], 4.471; p = .0242) significantly increased the risk of kyphosis. The probability of developing kyphosis decreased with an increase in the CLA (OR, 0.840; p = .0001), while the probability of developing kyphosis increased with an increase in the TS-CLA (OR, 1.104; p = .0044).

CONCLUSIONS

Preoperative cervical foraminal stenosis is an independent risk factor for cervical kyphosis following CLP. Thus, CLP may not be a suitable surgical option for cervical myelopathy combined with foraminal stenosis.

Cervical Spinous Process and Its Attached Muscles Maintain Lower Disk Lordosis: A Retrospective Study of 155 Patients Who Underwent Muscle-Preserving Double Laminectomies

Study Design

A retrospective study conducted at a single academic institution.

Purpose

This study compared the postoperative alignment of consecutive double laminectomies according to their decompression levels and investigated the influence of the extension unit of the spinous process and its attached muscles on postoperative alignment.

Overview of Literature

Many reports have investigated bony and soft tissue factors as the causes of postoperative cervical alignment disorders. To-this-date, no other article has clarified the importance of the attached muscles between the spinous processes of C3 and C6 to maintain local cervical alignment.

Methods

In total, 155 consecutive patients who underwent muscle-preserving consecutive double laminectomies for cervical spondylotic myelopathy from 2005 to 2013 were included in this study. The imaging parameters included the C2–C7 angle, range of motion, C2–C7 sagittal vertical axis (SVA), C7 slope, C2–C5 angle, C5–C7 angle, local disk angle caudal to the decompression level, and the disk height between C2/C3 and C7/Th1.

Results

The caudal disk angle of the decompression level decreased after consecutive double laminectomies, thus suggesting that the extension unit maintained the local lordosis at the lower disk of the decompression level. Postoperatively, in the C3–4 decompression cases, the C2–C7 angle decreased by 7.3°, and the C2–C7 SVA increased by 8.6 mm, thus indicating the appearance of an alignment disorder. Multivariate logistic regression analysis showed that cephalad laminectomy was a risk factor for C2–C7 angle decreases >10°. However, the postoperative recovery rate of Japanese Orthopedic Association scores after consecutive double laminectomies was reasonable, and the overall cervical alignment was well maintained in all decompression levels except C3–C4.

Conclusions

The cervical extension unit maintained lordosis at the disk caudal to it. The extension unit was found to contribute more to the maintenance of lordosis of the entire cervical spine at the cephalad side.

Long-term functional outcome of surgical treatment for degenerative cervical myelopathy

OBJECTIVE

Degenerative cervical myelopathy (DCM) is a major global cause of spinal cord dysfunction. Surgical treatment is considered a safe and effective way to improve functional outcome, although information about long-term functional outcome remains scarce despite increasing longevity. The objective of this study was to describe functional outcome 10 years after surgery for DCM.

METHODS

A prospective observational cohort study was undertaken in a university-affiliated neurosurgery department. All patients who underwent surgery for DCM between 2008 and 2010 as part of the multicenter Cervical Spondylotic Myelopathy International trial were included. Participants were approached for additional virtual assessment 10 years after surgery. Functional outcome was assessed according to the modified Japanese Orthopaedic Association (mJOA; scores 0-18) score at baseline and 1, 2, and 10 years after surgery. The minimal clinically important difference was defined as 1-, 2-, or 3-point improvement for mild, moderate, and severe myelopathy, respectively. Outcome was considered durable when stabilization or improvement after 2 years was maintained at 10 years. Self-evaluated effect of surgery was assessed using a 4-point Likert-like scale. Demographic, clinical, and surgical data were compared between groups that worsened and improved or remained stable using descriptive statistics. Functional outcome was compared between various time points during follow-up with linear mixed models.

RESULTS

Of the 42 originally included patients, 37 participated at follow-up (11.9% loss to follow-up, 100% response rate). The mean patient age was 56.1 years, and 42.9% of patients were female. Surgical approaches were anterior (76.2%), posterior (21.4%), or posterior with fusion (2.4%). The mean follow-up was 10.8 years (range 10-12 years). The mean mJOA score increased significantly from 13.1 (SD 2.3) at baseline to 14.2 (SD 3.3) at 10 years (p = 0.01). A minimal clinically important difference was achieved in 54.1%, and stabilization of functional status was maintained in 75.0% in the long term. Patients who worsened were older (median 63 vs 52 years, p < 0.01) and had more comorbidities (70.0% vs 25.9%, p < 0.01). A beneficial effect of surgery was self-reported by 78.3% of patients.

CONCLUSIONS

Surgical treatment for DCM results in satisfactory improvement of functional outcome that is maintained at 10-year follow-up.

Cervical Myelopathy: Diagnosis, Contemporary Treatment, and Outcomes

Cervical myelopathy is a clinical syndrome caused by compression of the spinal cord between the levels of the C1 and T1 vertebrae. Its clinical presentation can mimic other degenerative and neurological pathologies, making diagnosis challenging. Diagnosis is confirmed with appropriate imaging studies carefully correlated with history and physical examination. Treatment options are focused on decompression of the spinal canal from an anterior, posterior, or combined anterior and posterior surgical approach depending on the location of compression and patient factors. Outcomes are favorable if treatment is performed prior to severe symptom onset.

Adjacent Segment Stenosis after Muscle-Preserving Selective Laminectomy: A Retrospective Study of Patients with a Minimum 10-Year Follow-Up

Introduction

The present study aimed to understand the characteristics of adjacent segment stenosis post-surgery by examining the status of adjacent segment stenosis in patients with long-term follow-up after muscle-preserving selective laminectomy (SL).

Methods

We examined 43 patients who underwent muscle-preserving SL at a single academic institution and were followed up for >10 years. The C2-C7 angle, C2-C7 sagittal vertical axis, range of motion, and C7 slope were measured using an X-ray lateral view. The anterior-posterior diameter of the spinal cord (AP of SC) and anterior-posterior diameter of the dural tube (AP of dura) at adjacent segment were measured using magnetic resonance imaging T2-weighted sagittal section. Residual space for the spinal cord at the adjacent segment (SAC) was calculated as the difference between AP of SC and AP of dura.

Results

Four cases had cephalad adjacent segment stenosis at the last follow-up (upper stenosis (US) group), 9 cases had caudal adjacent segment stenosis ( lower stenosis (LS) group), and 30 cases had no stenosis (none (N) group). AP of SC, AP of dura, and SAC at the upper adjacent segment were significantly lower in the US group. AP of dura and SAC at the lower adjacent segment were significantly lower in the LS group. Multivariate logistic regression analysis revealed that the small AP of dura in the upper adjacent segment and small SAC in the lower adjacent segment were risk factors for developing a new stenosis.

Conclusions

Decompression should be considered beforehand in adjacent segments with small AP of SC and small AP of dura when performing cervical decompression.

Influence of Intervertebral Level of Stenosis on Neurological Recovery and Reduction of Neck Pain After Posterior Decompression Surgery for Cervical Spondylotic Myelopathy: A Retrospective Multicenter Study with Propensity Scoring

STUDY DESIGN

Retrospective multicenter study.

OBJECTIVE

To identify the impact of the intervertebral level of stenosis on surgical outcomes of posterior decompression for cervical spondylotic myelopathy (CSM).

SUMMARY OF BACKGROUND DATA

As the upper affected cervical levels in elderly patients result from degenerative changes in the lower cervical levels with aging, it is usually difficult to determine the influence of the upper affected cervical levels on surgical outcomes after posterior decompression for CSM in older age.

METHODS

This study involved 636 patients with CSM who underwent posterior decompression. According to the most stenotic intervertebral level, patients were divided into upper (n = 343, the most stenotic intervertebral level was C2/3, C3/4, or C4/5) and lower (n = 293, the most stenotic intervertebral level was C5/6, C6/7, or C7/T1) cervical stenosis groups. Propensity score matching of the baseline factors (characteristics, comorbidities, and neurological function) was performed to compare surgical outcomes, the Japanese Orthopaedic Association (JOA) scores, and visual analog scale (VAS) for neck pain between the upper (n = 135) and lower (n = 135) cervical stenosis groups.

RESULTS

Before propensity score matching, age at surgery was older and pre- and postoperative JOA scores were lower in the upper cervical stenosis group (P < 0.001, P < 0.001, and P < 0.001, respectively). Following matching, baseline factors were comparable between the groups. Postoperative JOA scores, preoperative-to-postoperative changes in the JOA scores, and the JOA score recovery rate were not significantly different between the groups (P = 0.866, P = 0.825, and P = 0.753, respectively). No differences existed in postoperative VAS for neck pain and preoperative-to-postoperative changes in VAS for neck pain between the groups (P = 0.092 and P = 0.242, respectively).

CONCLUSION

The intervertebral level of stenosis did not affect surgical outcomes after posterior decompression for CSM.Level of Evidence: 3.

Usefulness of Percutaneous Ultrasonography for Deciding the Need of Surgical Evacuation of Epidural Hematoma After Cervical Double-door Laminoplasty

STUDY DESIGN

This was a retrospective study.

OBJECTIVE

The objective of this study was to investigate the diagnostic utility of percutaneous ultrasonography (PUS) for postoperative epidural hematoma (EH) as a postoperative complication.

SUMMARY OF BACKGROUND DATA

We investigated the usefulness of PUS for determining the need of surgical evacuation of postoperative EH by comparing the postoperative magnetic resonance imaging (MRI) and PUS of the spinal cord.

MATERIALS AND METHODS

This study included patients who underwent cervical laminoplasty using suture anchors. Regular MRI and PUS were performed 1 week postoperatively. Whenever the patients exhibited neurological deterioration, MRI and PUS were performed. The spinal cord decompression status was classified into 3 grades using MRI and PUS. The existence of spinal pulsation was determined by PUS.

RESULTS

One hundred thirty-one patients were investigated. The decompression status by MRI and PUS, and the pulsation status by PUS showed a correlation with neurological deterioration (P<0.001). Four cases showed postoperative neurological deterioration and required revision surgery. The decompression status in these cases was classified as "poor" by both MRI and PUS, and as "no-pulsation" by PUS pulsation. The sensitivity and specificity for neurological deterioration was 100% and 95.1% in MRI decompression, 100% and 92.9% in PUS decompression, and 100% and 99.2% in PUS pulsation, respectively.

CONCLUSIONS

This is the first report that the disappearance of spinal pulsation was associated with neurological deterioration. PUS was useful in determining the need of surgical evacuation for postoperative EH. PUS should be the first choice of examination in the event of postoperative neurological deterioration following a cervical laminoplasty. When the disappearance of pulsation is confirmed, an additional hematoma evacuation surgery should be considered immediately without undertaking MRI.

LEVEL OF EVIDENCE

Level III.

The Kappa Line as a Regional Modification of the K-line: A Predictor of Neurological Outcome and Indicator of the Adequate Level of Decompression in Selective Laminoplasty

STUDY DESIGN

This is a retrospective cohort study.

OBJECTIVE

The aim was to introduce Kappa line (modification of K-line) for the prediction of postoperative neurological recovery after selective cervical laminoplasty (LMP) and use in determining the decompression level.

SUMMARY OF BACKGROUND DATA

The K-line is a radiographic marker that can predict prognosis and aid in surgical planning for patients undergoing LMP through C3 to C7. However, its efficacy in LMP involving limited segments is unclear. Furthermore, no specific radiographic marker to predict the prognosis of selective LMP has been reported.

MATERIALS AND METHODS

Fifty-one consecutive patients with a minimum 2-year follow-up after selective LMP for cervical myelopathy caused by ossification of posterior longitudinal ligament were retrospectively reviewed. The Kappa line was defined as a straight line connecting the midpoints of the spinal canal made by remaining bony structure after decompression procedures on a plain lateral radiograph in the neutral position. Patients were classified as K-line (+) or (-) and Kappa line (+) or (-) based on whether the ossified mass crossed the indicator line.

RESULTS

The Kappa line (+) group demonstrated significantly higher Japanese Orthopaedic Association (JOA) recovery rate (P=0.01), final JOA score (P<0.01), and dural sac diameter (P<0.01) postoperatively than the Kappa line (-) group. Cord compression grade was significantly lesser in the Kappa line (+) group. However, the K-line-based classification did not demonstrate significant difference in JOA recovery rate, final JOA score, and cord compression grade between the (+) and (-) groups; the dural sac diameter was significantly higher in the K-line (+) group (P<0.01).

CONCLUSIONS

The Kappa line showed better correlation with ossification of posterior longitudinal ligament size and cervical alignment, providing better prediction of neurological recovery and remaining cord compression following selective LMP. Therefore, the Kappa line can aid in determining the level of decompression in selective LMP.

Laminoplasty Achieves Improved Outcomes Despite Leading to a More Positive Sagittal Balance: Neither Preoperative Nor Postoperative Sagittal Balance Correlated With Spine-specific Outcome Data

STUDY DESIGN

A retrospective study of prospective data.

OBJECTIVE

Determine the correlation between cervical sagittal alignment, either preoperative or postoperative, and the outcomes of laminoplasty.

SUMMARY OF BACKGROUND DATA

Cervical laminoplasty is a common surgical treatment for myelopathy. However, the effect of preoperative or postoperative cervical sagittal alignment on outcomes, such as neurological improvement and patient-reported outcomes, remains unclear.

METHODS

A total of 144 consecutive patients (2007-2017) with laminoplasty for myelopathy and a minimum of 1-year postoperative follow-up were reviewed. The severity of myelopathy was assessed by modified Japanese Orthopedic Association (mJOA) scores. Total pain was measured by the visual analog scale. Patient-reported outcome included neck disability index (NDI) and 12-item short-form survey (SF-12). Radiographic measures of cervical sagittal alignment on x-ray images consisted of C2-C7 angle, T1 slope, C2-C7 sagittal vertical axis (SVA), and C2-C7 forward pitch (FP). Patients were also divided into 2 groups based on the postoperative C2-C7 SVA (≥40 or <40 mm) for outcome comparison.

RESULTS

Laminoplasty yielded improvement in functionality as evidenced by significantly increased mJOA scores, decreased total pain scores, and improved NDI scores at final follow-up. There was a change in sagittal balance postoperatively with significantly increased C2-C7 SVA and FP (7-8 mm increase). However, there was no correlation between preoperative sagittal alignment and outcomes. There was also no correlation between postoperative sagittal alignment and most outcomes, except for a significantly negative correlation between FP and short form-physical component summary (Spearman r=-0.328, P=0.011). When those with postoperative C2-C7 SVA ≥40 mm (n=60) were compared with those with <40 mm (n=84), there was no significant difference in outcomes.

CONCLUSIONS

Cervical laminoplasty yields significant neurological and functional improvement despite a more positive sagittal balance postoperatively, with increased C2-C7 SVA and FP. However, other than a lower short form-physical component summary score, neither preoperative nor postoperative sagittal alignment measures correlated with spine-specific outcomes.

LEVEL OF EVIDENCE

Level II-a retrospective cohort study.

Double Dome Laminoplasty: A Novel Technique for C2 Decompression

Objective

To introduce a new surgical technique - double dome laminoplasty for decompression of the entire C2 lamina and preservation of an extensor muscle insertion.

Methods

Eleven consecutive cervical myelopathy patients due to ossification of the posterior longitudinal ligament involving the Axis (C2) area were contained at this study. Direct decompression was evaluated as an increasing rate in space available cord (%) and posterior cord shift (mm) at C2 level. The Japanese Orthopaedic Association (JOA) score, visual analogue scale, and C2–7 Cobb angle in a neutral lateral x-ray were analyzed.

Results

The mean increase in space available for spinal cord at the C2 level, average posterior cord shift, and JOA recovery rate were 69.7%, 5.3±0.15 mm, and 58.0%, respectively. Cervical lordotic angle was maintained in all patients. One patient reported neck pain (visual analogue scale 6) postoperatively. No specific complications such as C2 laminar fracture or insufficient decompression were observed.

Conclusion

We recommend double dome laminoplasty for treating patients with cervical myelopathy involving the C2 area to avoid C2 laminectomy, reduce postoperative neck pain, and maintain lordotic cervical spine alignment.

Long-term Clinical Outcomes of Microendoscopic Laminotomy for Cervical Spondylotic Myelopathy: A 5-Year Follow-up Study Compared With Conventional Laminoplasty

STUDY DESIGN

This was a retrospective cohort study.

OBJECTIVE

The objective of this study was to characterize the long-term clinical and radiographic results of articular segmental decompression surgery using endoscopy [cervical microendoscopic laminotomy (CMEL)] for cervical spondylotic myelopathy (CSM) and to compare outcomes to conventional expansive laminoplasty (ELAP).

SUMMARY OF BACKGROUND DATA

The spinal cord compression in CSM consists of a pincer mechanism due to bulging disk and a hypertrophied ligamentum flavum. The long-term clinical benefits of segmental decompression surgery, which removes the dorsal compressive elements of articular segment in CSM patients, have not yet been elucidated.

MATERIALS AND METHODS

Consecutive patients with CSM who required surgical treatment were enrolled. All enrolled patients (n=81) underwent CMEL or ELAP. All patients were followed postoperatively for >5 years. The preoperative and 5-year follow-up evaluation included neurological assessment [Japanese Orthopaedic Association (JOA) score], JOA recovery rates, axial neck pain (visual analog scale), and cervical sagittal alignment (C2-C7 subaxial cervical angle).

RESULTS

Sixty-four patients (CMEL group: 33, ELAP group: 31) were included for analysis. The preoperative JOA score was 10.1 points in the CMEL group and 11.1 points in the ELAP group (P=0.15). The JOA recovery rates were similar, 58.6% in the CMEL group and 55.2% in the ELAP group (P=0.55). The axial neck pain in the CMEL group was significantly lower than that in the ELAP group (P<0.01). At 5-year follow-up, cervical alignment was more favorable in the CMEL group, with an average 2.9 degrees gain in lordosis [vs. 2.3 degrees loss of lordosis in the ELAP group (P<0.05)] and lower incidence of postoperative kyphosis.

CONCLUSIONS

CMEL is a novel, less invasive, technique that allows for multilevel posterior cervical decompression for treatment of CSM. Our 5-year follow-up data demonstrates that patients after CMEL have similar neurological outcomes to conventional laminoplasty, with significantly less postoperative axial pain and improved subaxial cervical lordosis when compared with their traditional laminoplasty counterparts.

Comparison of Surgical Outcomes After Open- and Double-Door Laminoplasties for Patients with Cervical Ossification of the Posterior Longitudinal Ligament: A Prospective Multicenter Study

STUDY DESIGN

A prospective multicenter study.

OBJECTIVE

To evaluate and compare the surgical outcomes after open-door (OD) and double-door (DD) laminoplasties in subjects with cervical ossification of the posterior longitudinal ligament (OPLL).

SUMMARY OF BACKGROUND DATA

Although previous studies compared clinical results after OD and DD laminoplasties, they were performed at a single institution with a relatively small sample size targeting mixed pathologies, including cervical spondylotic myelopathy.

METHODS

This study was performed by the Japanese Multicenter Research Organization for Ossification of the Spinal Ligament. A total of 478 patients with myelopathy caused by cervical OPLL from 28 institutions were prospectively registered from 2014 to 2017 and followed up for 2 years. Of these, 41 and 164 patients received OD and DD laminoplasties, respectively. Demographic information, medical history, and imaging findings were collected. Clinical outcomes were assessed using the cervical Japanese Orthopaedic Association, Japanese Orthopaedic Association Cervical Myelopathy Evaluation Questionnaire, and visual analog scale scores.

RESULTS

Age, sex, symptom duration, and comorbidities were not significantly different between the groups. Segmental ossification was the most frequent in both the groups. No significant differences in K-line type, canal occupying ratio, C2 to C7 angles, and range of motion were found. Both the procedures reduced the cervical range of motion postoperatively. A comparable frequency of perioperative complications was observed between the groups. The cervical Japanese Orthopaedic Association scores showed a similar improvement at 2 years postopera- tively. The reduction in visual analog scale score for neck pain was favorable in the OD group (P = 0.02), while other pain assessments did not show any significant differences between the groups. The functional outcomes assessed using the Japanese Orthopaedic Association Cervical Myelopathy Evaluation Questionnaire presented equivalent effective rates.

CONCLUSION

The results demonstrated almost comparable surgical outcomes between OD and DD laminoplasties. Lamino- plasty is a valuable technique as a therapeutic option for cervical OPLL.Level of Evidence: 2.

Biomechanical Analysis of Posterior Ligaments of Cervical Spine and Laminoplasty

Cervical laminoplasty is a valuable procedure for myelopathy but it is associated with complications such as increased kyphosis. The effect of ligament damage during cervical laminoplasty on biomechanics is not well understood. We developed the C2–C7 cervical spine finite element model and simulated C3–C6 double-door laminoplasty. Three models were created (a) intact, (b) laminoplasty-pre (model assuming that the ligamentum flavum (LF) between C3–C6 was preserved during surgery), and (c) laminoplasty-res (model assuming that the LF between C3–C6 was resected during surgery). The models were subjected to physiological loading, and the range of motion (ROM), intervertebral nucleus stress, and facet contact forces were analyzed under flexion/extension, lateral bending, and axial rotation. The maximum change in ROM was observed under flexion motion. Under flexion, ROM in the laminoplasty-pre model increased by 100.2%, 111.8%, and 98.6% compared to the intact model at C3–C4, C4–C5, and C5–C6, respectively. The ROM in laminoplasty-res further increased by 105.2%, 116.8%, and 101.8% compared to the intact model at C3–C4, C4–C5, and C5–C6, respectively. The maximum stress in the annulus/nucleus was observed under left bending at the C4–C5 segment where an increase of 139.5% and 229.6% compared to the intact model was observed for laminoplasty-pre and laminoplasty-res model, respectively. The highest facet contact forces were observed at C4–C5 under axial rotation, where an increase of 500.7% and 500.7% was observed compared to the intact model for laminoplasty-pre and laminoplasty-res, respectively. The posterior ligaments of the cervical spine play a vital role in restoring/stabilizing the cervical spine. When laminoplasty is performed, the surgeon needs to be careful not to injure the posterior soft tissue, including ligaments such as LF.

Impacts of postoperative changes of segmental mobility on neurological improvement after laminoplasty for cervical ossification of the posterior longitudinal ligament

Several studies have demonstrated that the dynamic factor at the mobile segment affects the severity of myelopathy in patients with cervical ossification of the posterior longitudinal ligament (C-OPLL), and posterior decompression supplemented with posterior instrumented fusion at the mobile segment provides good neurological improvement. However, there have been few reports of changes in range of motion at the mobile segment (segmental ROM) after laminoplasty (LP). The aim of this study was thus to retrospectively investigate changes in segmental ROM after LP and the impacts of these changes on neurological improvement in patients with C-OPLL.A total of 51 consecutive patients who underwent LP for C-OPLL since May 2010 and were followed for at least 2 years after surgery were included in this study. Neurological status was assessed using the Japanese Orthopaedic Association (JOA) score before surgery and at 2-year follow-up. Segmental ROM at the responsible level for myelopathy was measured preoperatively and at 2-year follow-up using lateral flexion-extension radiographs of the cervical spine.The mean JOA score improved significantly from 10.7 points preoperatively to 13.5 points at 2 years after surgery (mean recovery rate, 45.0%). The mean segmental ROM decreased significantly from 6.5 degrees before surgery to 3.2 degrees at 2 years after surgery. In the good clinical outcome group (recovery rate of the JOA score ≥50%; n = 22), the mean segmental ROM decreased significantly from 5.8 degrees preoperatively to 3.0 degrees postoperatively. It also decreased significantly from 7.1 degrees to 3.4 degrees in the poor clinical outcome group (recovery rate of the JOA score <50%; n = 29).This study showed that segmental ROM was stabilized after LP in most patients with C-OPLL. Neither preoperative nor postoperative segmental ROM showed significant differences between the good and poor clinical outcome groups and neither a postoperative increase nor decrease of segmental ROM significantly affected the recovery rate of the JOA score.

Spino cranial angle as a predictor of loss of cervical lordosis after laminoplasty in patients with cervical myelopathy

Background

To explore the relationship between spino cranial angle (SCA) and loss of cervical lordosis (LOCL), and to determine whether SCA has the ability to predict LOCL for patients with cervical myelopathy.

Methods

A total of 68 consecutive patients with cervical myelopathy who received laminoplasty (LAMP) were selected to the current study. C2–C7 lordosis was defined as a representation of the cervical alignment. Alignment change > 0° was considered LOCL. Multiple linear regression analysis was applied to evaluate the association between LOCL and various sagittal parameters at preoperative, such as SCA, CL, T1s and cSVA. Linear regression analysis was applied to evaluate the relationships between LOCL and preoperative SCA in each subgroup.

Results

Patients were assigned to three groups depending on the quartile of preoperative SCA. The first quarter of patients were defined as the low SCA group, the last quarter were defined as the high SCA group and the middle half were defined as the middle SCA group. There was no statistically significant difference in age, sex and the type of OPLL among the three groups. Patients in the low SCA group showed more cervical lordosis before surgery and more LOCL after LAMP (p < 0.001). After linear regression analysis for SCA and LOCL, preoperative SCA was negatively correlated with LOCL in the low SCA group (r = − 0.857, p < 0.001) and high SCA group (r = − 0.515, p = 0.034). However, there was no significant correlation between preoperative SCA and LOCL in the middle SCA group (r = 0.027, p = 0.881).

Conclusions

Patients with lower SCA had more lordosis preoperatively and performed more LOCL after LAMP at 2 years of follow-up. Both too high or low preoperative SCA were negatively correlated with the degree of LOCL, while when the SCA fluctuates in a suitable range, it is easier to compensate for the changes of cervical sagittal alignment.

Expansion of Spinal Canal with Lift-Open Laminoplasty: A New Method for Compression Cervical Myelopathy

OBJECTIVE

This study is to introduce lift-open laminoplasty and verify the increase of the spinal canal area following this surgical technique according to the preoperative anatomical measurement.

METHODS

There are 82 patients (43 male and 39 female) analyzed in our study from January 2019 to December 2020. The average age was 63.2 ± 3.21 years (from 41 to 84 years). All of them were treated with open-door laminoplasty, with a decompression segment range from C3 to C6. The increase of the spinal canal area after open-door laminoplasty was measured on postoperative CT images of the patients, and the distances between both lamina-facet junctions and lamina length was measured on preoperative CT images. Using the Pythagorean theorem for the equation of calculation area after the expansile open-door laminoplasty. Based on previous measurement parameters, spinous process length, lateral mass width, distance between osteotomy line and lamina-facet junctions line were additionally measured on preoperative CT images. Pythagorean theorem was used for calculating the area after the expansile lift-open laminoplasty. The results were recorded and a statistical analysis was undertaken. Then, there were six patients (five male and one female) treated with lift-open laminoplasty on C6, open-door on C3-C5, who suffer from cervical spondylotic myelopathy from December 2020 to January 2021. The average age was 60.3 ± 1.7 years (from 56 to 71 years). Operation time, blood loss, and Japanese Orthopaedic Association (JOA) score recovery rate were recorded. Intraoperative and postoperative complications were observed.

RESULTS

The increase of the spinal canal area after open-door laminoplasty measured on postoperative CT images was 123.01 ± 17.06 mm² and the calculation of the increase of the spinal canal areausing the Pythagorean theorem after open-door laminoplasty was 122.86 ± 15.86 mm² . A comparison of the actual value with calculative value showed no significant difference (T value = 0.057, P value = 0.955). The calculation of the increase of the spinal canal area after lift-open laminoplasty was 183.57 ± 62.99 mm² , which was larger than that after open-door laminoplasty (T value = 8.462, P value < 0.001). Mean operation time was 153.3 min and operative blood loss was 600 mL of the six patients treated with lift-open laminoplasty. At 1 month follow-up, all patients had recovered well. JOA score recovery rate was 37.6% and no intraoperative and postoperative complications occurred.

CONCLUSION

Lift-open laminoplasty could preserve nearly 100% of extensor muscle, avoid damaging C7 paraspinal muscles and C6-7 posterior muscle-ligament complex, reconstruct the spinous process firmly in the midline, and expand adequate spinal canal area after operation. These advantages could reduce the incidence rate of complications and bring better clinical results than traditional laminoplasty.

Preoperative Radiological Parameters to Predict Clinical and Radiological Outcomes after Laminoplasty

Many studies have focused on pre-operative sagittal alignment parameters which could predict poor clinical or radiological outcomes after laminoplasty. However, the influx of too many new factors causes confusion. This study reviewed sagittal alignment parameters, predictive of clinical or radiological outcomes, in the literature. Preoperative kyphotic alignment was initially proposed as a predictor of clinical outcomes. The clinical significance of the K-line and K-line variants also has been studied. Sagittal vertical axis, T1 slope (T1s), T1s-cervical lordosis (CL), anterolisthesis, local kyphosis, the longitudinal distance index, and range of motion were proposed to have relationships with clinical outcomes. The relationship between loss of cervical lordosis (LCL) and T1s has been widely studied, but controversy remains. Extension function, the ratio of CL to T1s (CL/T1s), and Sharma classification were recently proposed as LCL predictors. In predicting postoperative kyphosis, T1s cannot predict postoperative kyphosis, but a low CL/T1s ratio was associated with postoperative kyphosis.

Modified K-line for Making Decisions Regarding the Surgical Approach in Patients with K-line (-) OPLL

Objective

To investigate whether the modified K‐line can be used to predict the clinical outcome and to determine the surgical approach for K‐line (−) patients with cervical ossification of the posterior longitudinal ligament (OPLL).

Methods

A new modified K‐line was defined as the line connecting the midpoints of the spinal cord at C₄ and C₆ on the lateral cervical radiographs. A total of four consecutive patients (three men and one woman) with cervical myelopathy due to OPLL were included in this research. The patients were diagnosed with OPLL with K‐line (−) while they were also classified as modified K‐line (+). Preoperative modified K‐line was used to predict the surgical outcome in K‐line (−) patients with OPLL according to the original K‐line. And a modified laminoplasty with C₃ laminectomy and C_4‐6 bilateral open‐door laminoplasty was adopted to perform on all the patients. The Japanese Orthopaedic Association scores before surgery and at 1‐year follow‐up after surgery were evaluated and the recovery rate was calculated. The visual analogue scale (VAS) scores were also evaluated before surgery and after surgery. Furthermore, cervical plain radiographs in neutral position before surgery and after surgery were obtained to measure C₂–C₇ angles for assessing the cervical sagittal alignment.

Results

The results showed that good neurological improvement could be achieved in all K‐line (−) patients who underwent C₃ laminectomy with C₄–C₆ bilateral open‐door laminoplasty. The Postoperative JOA scores improved from 13.5 to 16.5, from 11 to 16.5, from 13 to 16, and from 12.5 to 13, respectively. The mean recovery rate was 65.4% in the K‐line (−) patients. And the VAS scores dropped from 3 to 1, 5 to 2, 5 to 3, and 4 to 2, respectively. The JOA and VAS scores showed satisfaction in all patients at the 1‐year follow‐up. Relatively satisfactory and stable cervical sagittal alignment was observed on postoperative lateral radiography in all patients at the 3‐month follow‐up period. There were no postoperative complications associated with this technique found in all the patients.

Conclusions

Modified K‐line may predict the clinical outcome of this modified laminoplasty and offer guidance regarding the choice of surgical method for K‐line (−) patients with OPLL. Additionally, C₃ laminectomy with C₄–C₆ bilateral open‐door laminoplasty should be recommended for the use in patients with K‐line (−) OPLL, who were also classified as modified K‐line (+). However, further studies with more cases will be required to reveal its generalizability and availability.

Simultaneous or Staged Decompressions for Patients with Tandem Spinal Stenosis

Objective

To compare the clinical effects of cervical decompression first, lumbar decompression first, or simultaneous decompression of both lesions in the treatment of tandem spinal stenosis (TSS).

Methods

This is a retrospective analysis. From January 2013 to December 2018, 51 TSS patients underwent our surgery and postoperative investigation. Among the 51 subjects, 27 females and 24 males, aged 49–77 years with an average age of 66.3 ± 6.8, were selected. According to the different operation sequences, all patients were divided into three groups. In simultaneous operation group, five patients underwent cervical and lumbar vertebrae surgery at the same time. In first cervical surgery group, 28 patients underwent cervical vertebra surgery first, followed by lumbar spine surgery after a period of recovery. And in first lumbar surgery group, 18 patients underwent lumbar vertebrae surgery first. The choice for neck surgery is posterior cervical single‐door vertebroplasty, the surgery of lumber is plate excision and decompression needle‐rod system internal fixation. The outcome measures are visual analogue scale (VAS), Japanese Orthopaedic Association cervical (JOA‐C) and lumbar (JOA‐L) scores, which were assessed at 3 months and 1 year after the operation by telephone interview. In addition, operative time, estimated blood loss, and hospital stay were also recorded.

Results

All the patients in the study had surgery performed successfully by the same group of orthopaedic surgeons. The preoperative VAS scores of simultaneous operation group, first cervical surgery group, and first lumbar surgery group were 8.00 ± 1.00, 8.36 ± 0.68, and 8.17 ± 0.71 (P > 0.05). The preoperative JOA‐C scores were 7.00 ± 2.35, 6.54 ± 1.53, and 7.83 ± 1.04 (P < 0.05). And the preoperative JOA‐L scores were 7.20 ± 2.17, 4.64 ± 2.36, and 5.78 ± 1.22 respectively (P < 0.05). During the final 1‐year follow‐up, the JOA‐C improvement rates of simultaneous operation group, first cervical surgery group, and first lumbar surgery group were 85.68% ± 5.44%, 84.27% ± 5.02%, and 83.34% ± 10.25%, respectively (P > 0.05), and the JOA‐L improvement rates were 80.04% ± 3.35%, 81.65% ± 3.74%, and 80.21% ± 4.76% (P > 0.05). The difference among them was not statistically significant. In addition, operation time (OP), blood loss (BL), and hospital stay (HS) in the simultaneous operation group were 245.00 ± 5.00 min, 480.00 ± 27.39 mL, and 16.60 ± 0.55 days, respectively. While those parameters in the first cervical surgery group were 342.50 ± 18.18 min, 528.21 ± 43.97 mL, and 22.75 ± 2.15 days, and in the first lumbar surgery group they were 346.11 ± 24.77 min, 519.44 ± 43.99 mL, and 22.89 ± 1.64 days. The average blood loss in simultaneous operation group was less (P > 0.05); meanwhile, the operation time and hospital stay time were significantly shorter in the simultaneous operation group than in the first cervical surgery group and first lumbar surgery group (P < 0.05). Only one case of fat liquefaction occurred in first cervical surgery group, which healed spontaneously after a regular change of dressing for 1 month.

Conclusions

Under the condition of ensuring the surgical effect, the choice of staged surgery or concurrent surgery according to the patients' own symptoms of cervical and lumbar symptoms could both obtain satisfactory results, and the damage of simultaneous surgery was less than that of staged surgery.

A Multicenter Observational Study on the Postoperative Outcomes of C3 Laminectomy in Cervical Double-door Laminoplasty

STUDY DESIGN

Multicenter retrospective observational study.

OBJECTIVE

To determine the differences between C3 laminectomy (LN) and C3 laminoplasty (LP) in cervical LP.

SUMMARY OF BACKGROUND DATA

Interlaminar bony fusion after cervical LP is reported to be related to a decrease in postoperative range of motion (ROM) or neurological disorder. However, it remains uncertain whether C3 LN affects patient-reported outcomes, especially after double-door LPs. Therefore, this study aimed to investigate the effect of C3 LN compared with C3 LP in cervical double-door LP.

PATIENTS AND METHODS

Using our prospective database, consecutive patients with degenerative cervical myelopathy undergoing cervical double-door LP in 7 hospitals between April 2017 and May 2018 were enrolled. Before and 1 year after the surgeries, we collected the details of patient background data, operative factors, radiologic findings such as C2-C7 ROM angle and C2-C3 interlaminar bony fusion, the Japanese Orthopaedic Association (JOA) score, postoperative satisfaction, neck pain, and patient-reported outcomes such as Short Form-12 (SF-12), EuroQol 5 Dimension (EQ-5D), Neck Disability Index (NDI), and the Core Outcome Measures Index (COMI) for the neck.

RESULTS

In all, 152 patients were enrolled, including 97 undergoing C3 LP and 55 undergoing C3 LN. There were no significant differences in patient background data, complications, and operative factors. C2-C3 interlaminar bony fusion occurred more often in the C3 LP group (22.6% vs. 5.7%). There were also no differences in the C2-C7 angle, C2-C7 ROM angle, the JOA score, patient satisfaction, neck pain, SF-12, EQ-5D, NDI, and COMI between the groups.

CONCLUSIONS

C2-C3 bony fusion after cervical double-door LP occurred more often in the C3 LP group than in the C3 LN group. C3 LN resulted in similar outcomes in complication rate, radiographic outcomes, and clinical outcomes compared with those of C3 LP.

LEVEL OF EVIDENCE

Level III.

Diabetes Does Not Adversely Affect Neurological Recovery and Reduction of Neck Pain After Posterior Decompression Surgery for Cervical Spondylotic Myelopathy: Results From a Retrospective Multicenter Study of 675 Patients

STUDY DESIGN

Retrospective multicenter study.

OBJECTIVE

The aim of this study was to identify the impact of diabetes on surgical outcomes of posterior decompression for cervical spondylotic myelopathy (CSM).

SUMMARY OF BACKGROUND DATA

Although some previous studies have reported surgical outcomes of posterior decompression for CSM in diabetic patients, their results were inconsistent.

METHODS

We included 675 patients with CSM who underwent posterior decompression. Patients were divided into diabetic (n = 140) and nondiabetic (n = 535) groups according to the diabetic criteria for glucose intolerance. Surgical outcomes as assessed by the Japanese Orthopedic Association (JOA) scores and visual analog scale (VAS) for neck pain were compared between groups. Subsequently, the functional outcomes of diabetic patients were compared between the mild (n = 131) and moderately severe (n = 9) groups. All patients were followed up for at least 1 year after surgery.

RESULTS

Compared with the nondiabetic group, the diabetic group showed lower pre- and postoperative JOA scores (P = 0.025 and P = 0.001, respectively) and a lower JOA score recovery rate (RR) (P = 0.009). However, the preoperative-to-postoperative changes in JOA scores in the diabetic and nondiabetic groups were not significantly different (P = 0.988). Pre- and postoperative VAS for neck pain and postoperative reduction of neck pain were comparable between groups (P = 0.976, P = 0.913 and P = 0.688, respectively). Although statistical analysis was not performed due to the small underpowered sample size, functional outcomes assessed by the JOA score RR (43.3 ± 37.1% vs. 45.3 ± 33.9%) and preoperative-to-postoperative changes in JOA scores (3.0 ± 2.2 vs. 2.7 ± 2.5) were similar between the mild and moderately severe diabetes groups.

CONCLUSION

CSM patients with diabetes experienced improvements in neurological function and neck pain as a result of posterior decompression to the same extent seen in patients without diabetes.Level of Evidence: 3.

Ten-Year Long-term Results of Modified Cervical Double-door Laminoplasty With C3 Laminectomy Preserving the Semispinalis Cervicis Inserted Into the Axis Compared With Those of Conventional Cervical Laminoplasty

STUDY DESIGN

A retrospective study.

OBJECTIVE

To compare long-term clinical and radiologic outcomes between conventional double-door laminoplasty (LP) (group A) and cervical LP with C3 laminectomy (group B).

SUMMARY OF BACKGROUND DATA

Cervical LP with C3 laminectomy preserving the semispinalis cervicis inserted into the axis decreased the patients' postoperative axial pain and muscle atrophy, prevented interlaminar bony fusion, decreased limitations of daily living activity, including reduced postoperative neck mobility, and maintained the cervical range of motion (ROM) more effectively than conventional cervical LP reattaching the semispinalis cervicis in the short-term.

MATERIALS AND METHODS

Group A included 14 patients with an average age of 56.6 years at the time of surgery (follow-up rate 58.1%), and group B included 21 patients with an average age of 56.3 years at the time of surgery (follow-up rate 29.1%). We evaluated the clinical results, which included the Japanese Orthopaedic Association (JOA) score, JOA Cervical Myelopathy Evaluation Questionnaire (JOACMEQ), and radiologic results, including C2-C7 ROM, number of interlaminar bony fusions and presence of new spondylolisthesis at C3.

RESULTS

There were no significant differences in preoperative and postoperative JOA scores, recovery rate of JOA score, and JOACMEQ. Significantly fewer patients in group B experienced interlaminar bony fusion at C2-C3 compared with those in group A. There was no significant difference in the presence of new spondylolisthesis at C3. In patients with cervical spondylotic myelopathy, the rate of decrease of C2-C7 ROM was significantly less in group B than in group A. In patients with ossification of the posterior longitudinal ligament, there was no significant difference in the rate of decrease of C2-C7 ROM between the groups.

CONCLUSIONS

C3 laminectomy prevented interlaminar bony fusion at C2-C3. C3 laminectomy maintained cervical ROM in patients with cervical spondylotic myelopathy. There were no adverse events due to C3 laminectomy at 10 years postsurgery.

Time Course of Physical and Mental Well-being Improvements After Cervical Surgery

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

To elucidate the postoperative time course of improvements in physical and mental well-being in patients with cervical spondylotic myelopathy (CSM).

SUMMARY OF BACKGROUND DATA

Spinal surgeons should understand the postoperative course in detail. However, data are still needed regarding the time course of improvements in well-being, a fundamental aspect of human life, after cervical surgery for CSM.

METHODS

One hundred consecutive patients who underwent laminoplasty for CSM, with complete clinical data preoperatively and 3 months and 2 years postoperatively, were enrolled. The Short Form-36 physical component summary (PCS) and mental component summary (MCS) scores were used as parameters of physical and mental well-being, respectively, and 4.0 was defined as the minimal clinically important difference (MCID) for both parameters.

RESULTS

On average, PCS and MCS scores were significantly improved after surgery (P < 0.001, P=0.004, respectively). Moreover, 64 and 48 patients achieved meaningful improvement (>MCID) in PCS and MCS scores at 3 months postoperatively, with maintained improvement (to 2 yr) in 46/64 (71.9%) and 34/48 patients (70.8%), respectively (PCS vs. MCS: P = 0.912). Additionally, 15 of 36 patients (41.7%) and 8 of 52 patients (15.4%) achieved late improvement (meaningful improvement at 2 yr but not at 3 months) in PCS and MCS scores, respectively (PCS vs. MCS: P = 0.007). In multivariate regression analysis, improvement in cJOA score was significantly associated with PCS improvement, but not MCS improvement, at both 3 months and 2 years (P = 0.001, P > 0.001, respectively).

CONCLUSION

The overall outcome of physical well-being improvement is decided within 3 months postoperatively, in proportion to the recovery in myelopathy, with a relatively high chance of meaningful improvement over the next 21 months. The outcome of improvement in mental well-being is decided within 3 months postoperatively, independently from the recovery in myelopathy, with a low chance of meaningful improvement over the next 21 months.Level of Evidence: 3.

Risk Factors for Poor Outcome of Cervical Laminoplasty: Multivariate Analysis in 505 Patients with Cervical Spondylotic Myelopathy

The risk factors for poor outcome after cervical laminoplasty in patients with cervical spondylotic myelopathy (CSM) were demonstrated. These findings suggest that advanced age, long-term CSM symptoms, and lower score of preoperative 10-second step test are risk factors for poor cervical laminoplasty outcomes in patients with CSM.

Study Design..

A prospective study.

Objective..

The aim of this study was to characterize the risk factors for poor outcome following cervical laminoplasty in patients with cervical spondylotic myelopathy (CSM).

Summary of Background Data..

Previous research has identified a variety of potential predictive factors that might affect outcomes after cervical laminoplasty. However, no study till date has assessed the effects of such risk factors, including internal medicine comorbidity and quantitative performance tests, on the outcome of laminoplasty in a large series of patients with CSM.

Methods..

A total of 505 consecutive patients with CSM (311 males; 194 females; mean age, 66.6 years; age range, 41–91 years) who underwent double-door laminoplasty were prospectively included. The average postoperative follow-up period was 26.5 months (range, 12–66 months). We evaluated the recovery rate (RR) on the basis of the Japanese Orthopaedic Association score. Logistic regression analysis was performed to identify the risk factors for poor outcome, which was defined as a postoperative RR of <50%. Relationship between outcome and various clinical and imaging predictors was examined.

Results..

Two hundred ninety-five patients had good outcomes with RR >50%, whereas 210 patients had poor outcomes with RR <50%. Compared with the good-outcome group, the poor-outcome group had a significantly higher prevalence of diabetes and hypertension and use of anticoagulant/antiplatelet agent and smoking history (P < 0.05). Multivariate logistic regression analysis showed independent risks associated with increased age (odds ratio [ORs]  = 1.029, 95% confidence interval [CI] = 1.004–1054, P = 0.023). Logistic regression analysis determined that symptom duration of CSM (OR = 1.017, 95% CI = 1.008–1.026, P < 0.001) and preoperative 10-second step test (OR = 0.922, 95% CI = 0.865–0.983, P = 0.013) were significant risk factors for poor outcome.

Conclusion..

These findings suggest that advanced age, long-term CSM symptoms, and lower score of preoperative 10-second step test are risk factors for poor outcome in patients with CSM.

Level of Evidence: 2

Baseline severity of myelopathy predicts neurological outcomes after posterior decompression surgery for cervical spondylotic myelopathy: a retrospective study

STUDY DESIGN

Retrospective multicenter study.

OBJECTIVES

To identify the usefulness of the baseline severity of myelopathy for predicting surgical outcomes for cervical spondylotic myelopathy (CSM).

SETTING

Seventeen institutions in Japan.

METHODS

This study included 675 persons with CSM who underwent posterior decompression. According to baseline severity, the individuals were divided into the mild (Japanese Orthopaedic Association [JOA] score ≥ 14.5), moderate (JOA score = 10.5-14), and severe (JOA score ≤ 10) groups. Surgical outcomes and clinical variables were compared between the groups. Logistic regression analysis was used to develop a prediction model for unsatisfactory symptom state (postoperative JOA score ≤ 14, residual moderate or severe myelopathy).

RESULTS

The mean (±standard deviation) age was 67 ± 12 years. The participants in the severe group were older than those in the mild group. Postoperative JOA scores were higher in the mild group than in the severe group. According to multivariate logistic regression analysis, the prediction model included preoperative JOA scores (odds ratio [OR] 0.60; 95% confidence interval [CI] 0.55-0.67) and age (OR 1.06, 95% CI 1.04-1.08). On the basis of the model, a representative combination of the thresholds to maximize the value of "sensitivity - (1 - specificity)" demonstrated a preoperative JOA score of 11.5 as a predictor of postoperative unsatisfactory symptom state in people around the mean age of the study cohort (67 years).

CONCLUSIONS

The combination of the baseline severity of myelopathy and age can predict postoperative symptom states after posterior decompression surgery for CSM.

Cervical Lordosis Ratio as a Novel Predictor for the Loss of Cervical Lordosis After Laminoplasty

Objective

Maintaining cervical lordosis (CL) after laminoplasty is important for indirect decompression of the spinal cord. This study aimed to identify preoperative dynamic radiographic predictors for the loss of CL after laminoplasty.

Methods

We retrospectively analyzed 141 consecutive patients who underwent cervical laminoplasty for cervical myelopathy. The following radiographic parameters were measured before surgery and at 1 year of follow-up: CL, C7 slope, C2–7 sagittal vertical axis (SVA), C2–7 range of motion (ROM), CL in flexion, CL in extension, ROM of flexion (Flex ROM), and ROM of extension. The CL ratio (CLR) was defined as 100 × Flex ROM/C2–7 ROM. ΔCL was defined as postoperative CL minus preoperative CL. Patients were classified into 2 groups: group K (kyphotic change group, ΔCL ≤ -10) and group C (control group, ΔCL > -10).

Results

The patient population comprised 94 men and 47 women (mean age, 70.9 ± 9.4 years), with 24 patients (17.0%) classified into group K. CL, C7 slope, and CLR were significantly higher in group K than in group C. The groups did not significantly differ in age, sex, C2–7 SVA, and C2–7 ROM. On multivariable analysis, the CLR was significantly associated with postoperative kyphotic changes. On receiver-operating characteristic curve analysis (area under the curve = 0.717, p < 0.001), the cutoff value for CLR was 68.9%, with sensitivity and specificity of 87.5% and 57.3%, respectively.

Conclusion

The CLR, reflecting the balance between flexion and extension mobility, was identified as a novel predictor for CL loss after laminoplasty, with a cutoff value of 68.9%.

Analysis of Cervical Spine Alignment Change after Modified Kurokawa Cervical Laminoplasty in the Patients with Cervical Myelopathy and Straight Cervical Spine

Laminoplasty is widely used to decompress the spinal cord in patients with multilevel cervical lesions. Straight cervical alignment may not be a good candidate for laminoplasty because of postoperation progression of kyphosis and loss of cervical spine range of motion (ROM). However, clinical outcomes of laminoplasty did not show a strong and consistent effect based on cervical sagittal alignment. Moreover, the kyphosis progression and ROM change after operation for the patients with preoperative strange cervical alignment are still unclear. This study is to evaluate the change of cervical alignment and ROM in patients with straight cervical alignment after modified Kurokawa cervical laminoplasty. Thirty patients with multiple-level cervical spondylosis (CSM) and straight cervical alignment were included. All patients underwent laminoplasty with the reconstruction of the spinous process-ligament-muscular complex (SPLMC). The modified JOA score was analyzed for clinical assessment. The change of cervical alignment, ROM, T1 slope, and intervertebral disc space Cobb angle were analyzed for radiological assessment. The average JOA score at preoperative and 2 years follow-up were 7.8 ± 1.4 and 13.6 ± 2.1, respectively. The recovery ratio was 63%. At the 2 years follow-up, there were 18 patients who acquired lordotic cervical alignment. 10 patients remained as straight cervical curve, and 2 patients' cervical alignment developed mild kyphosis. 28 out of 30 patients showed improvement of cervical alignment. The cervical alignment was improved from 1.29 ± 10.04° preoperative to 9.58 ± 8.65° postoperative. However, the ROM decreased from 36.8 ± 18.92 preoperative to 25.08 ± 12.10° postoperative. A positive correlation was found between the C2/4 angle change and cervical alignment change, T1 slope and cervical alignment, cervical alignment, and neutral position flexion reserved ROM. A negative correlation was found between the C1/2 angle change and cervical alignment change. Laminoplasty with a reconstruction of SPLMC followed by appropriate postoperative muscle exercises may be an encouraging way to maintain or improve physiological alignment and prevent postoperation kyphosis deformity at 2 years follow-up.

Surgical treatment of concomitant atlantoaxial instability and subaxial spondylotic stenosis in rheumatoid arthritis-a case report

INTRODUCTION

This case report details the surgical treatment of an RA patient who presented with concomitant AAI and subaxial spondylotic stenosis and was subsequently treated via a C1-2 screw-rod construct, semispinalis cervicis sparing C3 laminectomy, and C4-C7 laminoplasty. Our case report is the first to describe a surgical approach for treatment of concomitant AAI and subaxial spondylotic stenosis in a patient with RA.

CASE PRESENTATION

A 66-year-old male with a history of rheumatoid arthritis and atlantoaxial instability presented to an outpatient spine clinic with complaints of neck pain and worsening gait imbalance. A flexion-extension MRI revealed compression of the posterior aspect of the C1 ring on the back of the spinal cord during flexion, resulting in cord deformation; subaxial spondylosis with moderate associated stenosis and congenital narrowing from C3-7; and central cord compression with T2 signal change at C5-6. A C1-2 arthrodesis was performed and the subaxial spinal cord was then decompressed by performing a seminspinalis-sparing C3 laminectomy, C4-6 laminoplasties, and C7 dome laminectomy. Follow-up flexion-extension radiographs demonstrated satisfactory hardware position at C1-2 and full range of motion at C3-7.

DISCUSSION

This is the first study to describe the surgical management of an RA patient with concomitant AAS and subaxial spondylotic stenosis. Patients with these simultaneous pathologies can be considered for decompression caudal to the C1-2 arthrodesis, though they should be adequately counseled regarding the risk of developing SAS requiring subsequent fusion.

Effects of Preservation of the Semispinalis Cervicis Inserted into C2 on Craniocervical Alignment After Laminoplasty

OBJECTIVE

The preservation of nuchal musculature is essential for preventing axial pain and cervical malalignment after laminoplasty. A few studies have examined the effect of preservation of nuchal musculature on the degenerative progression after laminoplasty. We aimed to clarify the influence of preservation of the semispinalis cervicis inserted into C2 on cervical degenerative change and alignment after laminoplasty.

METHODS

We retrospectively reviewed 106 consecutive patients who underwent C3-7 laminoplasty for cervical spondylotic myelopathy during 2006-2017. Patients were classified into 2 groups according to the preservation (P-group; n = 33) or detachment (D-group; n = 73) of the Semispinalis cervicis muscles inserted into the C2 spinous process. Parameters of cervical sagittal alignment, range of motion, and progressive degenerative changes next to or within the range of laminoplasty were evaluated in cervical spine radiographs, and magnetic resonance images obtained during follow-up period.

RESULTS

In the D-group, the postoperative C2-7 Cobb angle significantly decreased (-0.06°/month), while the O-C2 Cobb angle significantly increased (0.07°/month). In addition, the C2-7 range of motion significantly decreased in the D-group (-0.12°/month). Degenerative changes in the laminoplasty range were found in 5 patients per group. Three patients from the D-group developed retroodontoid pseudotumors (P < 0.001).

CONCLUSIONS

To maintain horizontal gaze, the craniocervical segment can compensate for the loss of lordosis by increasing the Cobb angle. Excessive compensation may exert mechanical stress on the atlantoaxial junction, contributing to the development of a retroodontoid pseudotumor. Preservation of the semispinalis cervicis inserted into C2 is critical for the prevention of malalignment after laminoplasty.

Comparative Five-Year Surgical Outcomes of Open-Door versus French-Door Laminoplasty in Multilevel Cervical Spondylotic Myelopathy

Objective

To compare the five-year surgical outcomes between Open-Door laminoplasty (ODL) and French-Door laminoplasty (FDL) in the management of multilevel cervical spondylotic myelopathy (MCSM).

Methods

Sixty patients with MCSM, who were operated by ODL or FDL, were included in this study and followed up for at least 5 years. The average follow-up period was 69.2 ± 3.2 months. The modified Japanese Orthopaedic Association (mJOA) score and radiological assessments including the Cobb angle and cervical range of motion (ROM) were evaluated and compared before surgery and at the final follow-up. The incidence of postoperative complications and medical costs were also compared.

Results

Both ODL and FDL groups achieved significant improvements of the mJOA score in postoperative 5 years; the average recovery rate (RR) of the mJOA score in the ODL and FDL groups was 72.14 ± 6.97% and 69.53 ± 7.51%, respectively. No statistically significant differences regarding the pre- and postoperative mJOA score, the RR of the mJOA score, the loss and the loss rate of the Cobb angle, and the incidence of postoperative complications existed between ODL and FDL. The mean loss and the loss rate of cervical ROM in the FDL group (18.70 ± 8.91°, 41.08 ± 11.17%) were significantly higher than those of the ODL group (13.81 ± 8.62°, 31.47 ± 12.43%) (P < 0.05). FDL reduced medical costs more greatly than ODL (33014.37 ± 3424.12 China Yuan versus 82096.62 ± 7093.07 China Yuan, P < 0.001).

Conclusions

Both ODL and FDL are effective for MCSM. The 5-year neurological results are similar between the two groups. ODL trends to be superior to FDL in postoperative preservation of cervical ROM while FDL reduced medical costs more greatly.

Accuracy of the Gutter Position in Cervical Double-door Laminoplasty Using Intraoperative Computed Tomography Navigation and the Factors Associated With C5 Palsy

STUDY DESIGN

This was a prospective study.

OBJECTIVE

This study aimed to investigate the accuracy of the gutter position after cervical double-door laminoplasty (LP) using intraoperative computed tomography (CT) navigation and the factors associated with C5 palsy.

SUMMARY OF BACKGROUND DATA

There were some reports in which the gutter position and the width of decompression in cervical LP were associated with C5 palsy; however, there were few reports about the accuracy of the gutter position.

MATERIALS AND METHODS

Thirty-three patients treated with cervical LP were enrolled. We marked our targeted gutter position on the lamina with a high-speed drill using intraoperative CT navigation and performed the LP procedure. The accuracy of the gutter position was evaluated with a postoperative CT scan. We measured the angle of the opened lamina (AOL), the proportion of the distance between the gutters and the distance of transverse diameter of spinal canal (PGSC) with a postoperative CT scan and spinal cord posterior shifting (SCPS) with preoperative and postoperative magnetic resonance imaging scans. We investigated the incidence of C5 palsy and analyzed AOL, PGSC, and SCPS between the C5 palsy (+) and (-) groups.

RESULTS

The accuracy of all gutter positions was 78.4% (182/232). The accuracy of the gutter position at the right C4 and right C7 was lower than that at the other levels. The AOL in all cases was ~60 degrees. The PGSC was 90.1%-97.2%. The SCPS at C5 was the largest with 2.2 mm. C5 palsy occurred in 3 of 33 patients (9.1%). There were no significant differences in the AOL, PGSC, or SCPS between the 2 groups.

CONCLUSIONS

The accuracy of the gutter position using intraoperative CT navigation was good. The incidence of C5 palsy was higher in this study than in the previous reports.