Muscle-Preserving Selective Laminectomy Maintained the Compensatory Mechanism of Cervical Lordosis After Surgery

Efficacy and safety of laminoplasty combined with C3 laminectomy for patients with multilevel degenerative cervical myelopathy: a systematic review and meta-analysis

PURPOSE

Laminoplasty (LP) combined with C3 laminectomy (LN) can effectively achieve spinal cord decompression while maintaining the integrity of the posterior ligament-muscle complex, thereby minimizing cervical muscle damage. However, its necessity and safety remain controversial. This study aimed to compare the safety and efficacy of LP and LP combined with C3 LN in the treatment of patients with multilevel degenerative cervical spondylotic myelopathy (DCM).

METHODS

A systematic review and meta-analysis of the literature was performed. A search of PubMed, Web of Science, Embase, and the Cochrane Library databases was conducted from inception through December 2023 and updated in February 2024. Search terms included laminoplasty, laminectomy, C3 and degenerative cervical spondylosis. The literature search yielded 14 studies that met our inclusion criteria. Outcomes included radiographic results, neck pain, neurologic function, surgical parameters, and postoperative complications. We also assessed methodologic quality, publication bias, and quality of evidence.

RESULTS

Fourteen studies were identified, including 590 patients who underwent LP combined with C3 LN (modified group, MG) compared to 669 patients who underwent LP (traditional group, TG). The results of the study indicated a statistically significant improvement in cervical range of motion (WMD = 3.62, 95% CI: 0.39 to 6.85) and cervical sagittal angle (WMD = 2.07, 95% CI: 0.40 to 3.74) in the MG compared to the TG at the last follow-up (very low-level evidence). The TG had a higher number of patients with complications, especially C2-3 bone fusion. There was no significant difference found in improvement of neck pain, JOA, NDI, cSVA, T1 slope at latest follow-up.

CONCLUSION

LP combined with C3 LN is an effective and necessary surgical method for multilevel DCM patients to maintain cervical sagittal balance. However, due to the low quality of evidence in existing studies, more and higher quality research on the technology is needed in the future.

Clinical and Radiological Outcomes in C2 Recapping Laminoplasty for the Pathologies in the Upper Cervical Spine

OBJECTIVE

To evaluate C2 muscle preservation effect and the radiological and clinical outcomes after C2 recapping laminoplasty.

METHODS

Fourteen consecutive patients who underwent C2 recapping laminoplasty around C1-2 level were enrolled. To evaluate muscle preservation effect, the authors conducted a morphological measurement of extensor muscles between the operated and nonoperated side. Two surgeons measured the cross-sectional area (CSA) of obliquus capitis inferior (OCI) and semispinalis cervicis (SSC) muscle before and after surgery to determine atrophy rates (ARs). Additionally, we examined range of motion (ROM), sagittal vertical axis (SVA), neck visual analogue scale (VAS), Neck Disability Index (NDI), and Japanese Orthopaedic Association (JOA) score to assess potential changes in alignment and consequent clinical outcomes following posterior cervical surgery.

RESULTS

We measured the CSA of OCI and SSC before surgery, and at 6 and 12 months postoperatively. Based on these measurements, the AR of the nonoperated SSC was 0.1% ± 8.5%, the AR of the operated OCI was 2.0% ± 7.2%, and the AR of the nonoperated OCI was -0.7% ± 5.1% at the 12 months after surgery. However, the AR of the operated side's SSC was 11.2% ± 12.5%, which is a relatively higher value than other measurements. Despite the atrophic change of SSC on the operated side, there were no prominent changes observed in SVA, C0-2 ROM, and C2-7 ROM between preoperative and 12 months postoperative measurements, which were 11.8 ± 10.9 mm, 16.3° ± 5.9°, and 48.7° ± 7.7° preoperatively, and 14.1 ± 11.6 mm, 16.1° ± 7.2°, and 44.0° ± 10.3° at 12 months postoperative, respectively. Improvement was also noted in VAS, NDI, and JOA scores after surgery with JOA recovery rate of 77.3% ± 29.6%.

CONCLUSION

C2 recapping laminoplasty could be a useful tool for addressing pathologies around the upper cervical spine, potentially mitigating muscle atrophy and reducing postoperative neck pain, while maintaining sagittal alignment and ROM.

Incidence and Risk Factors for the Development of Axial Symptoms Following Posterior Single-Door Laminoplasty: A Retrospective Analysis

OBJECTIVE

Posterior single-door laminoplasty is a widely practiced clinical procedure, but the occurrence of postoperative axial syndrome (AS) remains a significant concern. The aim of this study was to identify risk factors associated with AS and develop a risk prediction model.

METHODS

Clinical data from 226 patients who underwent posterior single-door laminoplasty between June 2017 and June 2022 were collected. Through Logistic model analysis, the risk factors of AS are clarified and the intensity of each risk factor is explained in the form of forest plot. Subsequently, we constructed a predictive model and plotted receiver operating characteristic curves to assess the model's predictive value.

RESULTS

In the end, 87 cases were diagnosed with AS, resulting in an incidence rate of 38.5%. Logistic regression analysis revealed that preoperative encroachment rate of anterior spinal canal (pre-op ERASC), intraoperative facet joints destruction, intraoperative open-door angle, postoperative loss of cervical curvature, and postoperative loss of cervical range of motion were independent risk factors for AS. Conversely, preoperative cervical curvature (pre-op CC) and postoperation early function training were protective factors against AS. The Youden index indicated that the cutoff values for pre-op ERASC and pre-op CC were 26.6°and 16.5, respectively. The risk prediction model for AS was constructed and a nomogram was plotted. The model has high clinical value.

CONCLUSIONS

Pre-op ERASC, pre-op CC, intraoperative facet joints destruction, intraoperative open-door angle, postoperative loss of cervical curvature, postoperative loss of cervical range of motion, and postoperation early function training are independent influencing factors for AS occurrence. The risk model has good practicability.

Comparative effectiveness and functional outcome of C3 & C7 dome-hybrid open-door laminoplasty with traditional unilateral open-door laminoplasty for cervical spondylotic myelopathy

OBJECTIVE

The C3 & C7 dome-hybrid open-door laminoplasty was proven to be an effective treatment for multi-levels cervical spondylotic myelopathy (CSM). However, its superiority over traditional unilateral open-door laminoplasty (UOLP) remains questionable, and no studies have compared the efficacy of this technique with traditional UOLP. This study aimed to compare the effectiveness of C3 & C7 dome-hybrid open-door laminoplasty with traditional UOLP in treating multi-levels CSM.

METHODS

A retrospective study of multi-levels CSM with laminoplasty was performed, including 35 cases of traditional UOLP and 27 cases of C3 & C7 dome-hybrid open-door laminoplasty. Radiographic evaluation parameters and clinical outcomes were recorded to evaluate the surgical effectiveness.

RESULTS

There was no significant difference in demographic baseline parameters. At the final follow-up, the C2-C7 Cobb angle of the modified group was significantly greater than that of the traditional group (p = 0.026). Meanwhile, the C2-C7 SVA of the modified group was significantly smaller than that of the traditional group (p = 0.009). Clinical outcomes such as VAS, NDI, and SF-12 scores, improved significantly in the modified group compared to the traditional group, while the JOA scores had no significant difference in both groups. There was no significant difference in the overall rate of complications between the two groups.

CONCLUSION

Both techniques have satisfactory outcomes in treating multi-levels CSM. Comparing with traditional UOLP, C3 & C7 dome-hybrid open-door laminoplasty has a greater superiority in reducing postoperative neck pain and maintaining the cervical sagittal alignment. It is proven to be a feasible management for patients with multi-levels CSM.

Unilateral biportal endoscopic supralaminar, posterior spinous process sparing approach for en bloc cervical laminectomy in case of cervical osteochondroma causing myelopathy: A case report

Background Context

Cervical osteochondroma is a rare cause of myelopathy. Traditional treatment is open laminectomy with or without fusion. There is limited literature on unilateral bi-portal endoscopic en-bloc resection of cervical osteochondroma.

Study Design

We describe a case of a 39-year-old male diagnosed with cervical compressive myelopathy. The pathologic site is located on the ventral surface of C4 lamina. Herein we describe a step-by-step method of unilateral biportal endoscopy (UBE) en-bloc resection of extra-dural sublaminar osteochondroma for patient who had cervical myeloradiculopathy. Spinous process sparing osteotomy was performed to conserve the spinous process and supraspinous ligament..

Outcome Measures

The patient was successfully treated via UBE and the operative time was 50 minutes with no intra-operative complications. Patient symptoms improved in the immediate postoperative period and by 3 months he regained fine motor functions of hand.

Conclusions

Unilateral biportal endoscopic en bloc cervical laminectomy can effectively decompress cervical spine and remove posterior benign cervical tumor. UBE preserves musculature and posterior ligamentous complex and thus reduces postoperative neck pain and postlaminectomy kyphosis.

Comparison of posterior muscle-preserving selective laminectomy and laminectomy with fusion for treating cervical spondylotic myelopathy: study protocol for a randomized controlled trial

BACKGROUND

Cervical spondylotic myelopathy (CSM) is the predominant cause of spinal cord dysfunction in the elderly. The patients are often frail and susceptible to complications. Posterior surgical techniques involving non-fusion are complicated by postlaminectomy kyphosis and instrumented fusion techniques by distal junction kyphosis, pseudarthrosis, or implant failure. The optimal surgical approach is still a matter of controversy. Since anterior and posterior fusion techniques have been compared without presenting any superiority, the objective of this study is to compare stand-alone laminectomy with laminectomy and fusion to determine which treatment has the lowest frequency of reoperations.

METHODS

This is a multicenter randomized, controlled, parallel-group non-inferiority trial. A total of 300 adult patients are allocated in a ratio of 1:1. The primary endpoint is reoperation for any reason at 5 years of follow-up. Sample size and power calculation were performed by estimating the reoperation rate after laminectomy to 3.5% and after laminectomy with fusion to 7.4% based on the data from the Swedish spine registry (Swespine) on patients with CSM. Secondary outcomes are the patient-derived Japanese Orthopaedic Association (P-mJOA) score, Neck Disability Index (NDI), European Quality of Life Five Dimensions (EQ-5D), Numeric Rating Scale (NRS) for neck and arm pain, Hospital Anxiety and Depression Scale (HADS), development of kyphosis measured as the cervical sagittal vertical axis (cSVA), and death. Clinical and radiological follow-up is performed at 3, 12, 24, and 60 months after surgery. The main inclusion criterium is 1-4 levels of CSM in the subaxial spine, C3-C7. The REDcap software will be used for safe data management. Data will be analyzed according to the modified intention to treat (mITT) population, defined as randomized patients who are still alive without having emigrated or left the study after 2 and 5 years.

DISCUSSION

This will be the first randomized controlled trial comparing two of the most common surgical treatments for CSM: the posterior muscle-preserving selective laminectomy and posterior laminectomy with instrumented fusion. The results of the myelopathy randomized controlled (MyRanC) study will provide surgical treatment recommendations for CSM. This may result in improvements in surgical treatment and clinical practice regarding CSM.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04936074 . Registered on 23 June 2021.

Does the asymmetry and extension function of the preoperative cervical paraspinal extensor predict postoperative cervical sagittal deformity in patients who undergo modified laminoplasty?

BACKGROUND CONTEXT

A previous study found that the cross-sectional area (CSA) of the preoperative cervical paraspinal extensors (CPEs) was associated with loss of cervical lordosis after laminoplasty, while a recent study found that CPE asymmetry was associated with symptoms of degenerative cervical myelopathy. Whether preoperative CPE asymmetry can predict cervical sagittal deformity (CSD) after laminoplasty is unknown.

PURPOSE

To assess whether asymmetry, degree of degeneration, and extension function of the CPE can be used as predictors of postoperative CSD in patients who undergo laminoplasty.

STUDY DESIGN

A retrospective study.

PATIENT SAMPLE

From January 2017 to December 2019, 55 patients with multilevel cord compression and myelopathic symptoms were enrolled.

OUTCOME MEASURES

The visual analog scale (VAS), neck disability index (NDI), and modified Japanese Orthopedic Association (mJOA) were used to assess cervical spinal function and quality of life.

METHODS

From January 2017 to December 2019, 55 patients undergoing modified laminoplasty were included. The following parameters were measured preoperatively and 24 months postoperatively on X-ray: (1) C0-C2 Cobb angle; (2) C2-C7 Cobb angle (CL); (3) T1 slope (T1S); (5) C2-C7 sagittal vertical axis (SVA); (6) T1S minus CL; (7) Preoperative extension function: Extension CL minus Neutral CL (EF). Preoperative global alignment parameters: (8) spino cranial angle, (9) C7-S1 sagittal vertical axis (C7 SVA), (10) pelvic incidence, (11) lumbar lordosis, (12) thoracic kyphosis. (13) Preoperative CPE parameters: Summation of bilateral total cross-sectional area (STCSA), summation of bilateral total cross-sectional area ratio (STCSAR), total cross-sectional area asymmetry, summation of bilateral functional cross-sectional area of muscle (SFCSA), summation of bilateral functional cross-sectional area of muscle ratio (FCSAR), and functional cross-sectional area of muscle asymmetry (FCSAA). The VAS, mJOA, and NDI were used to evaluate cervical spine function and quality of life. Patients were divided into the CSD group and the non-deformed group (N-CSD) group postoperatively, and the parameters between the two groups were compared. The Pearson correlation coefficient was used to evaluate the relationship between the parameters, and multiple regression analysis and ROC curve analysis were used to determine the predictors and key values.

RESULTS

Compared with functional scores, mJOA in the CSD group was significantly lower than that in the N-CSD group, while NDI and VAS were significantly higher. Postoperative CL was significantly correlated with EF, SFCSA/STCSA (C3-C6), SFCSAR (C4 and C6), STCSAR (C6), and FSCAA (C6). T1S minus CL was significantly correlated with EF, SFCSA/STCSA (C3-4 and C6), SFCSAR (C4 and C6), STCSAR (C6) and FSCAA (C6). C2-7 SVA was significantly correlated with EF, SFCSAR (C4 and C6), STCSAR (C6), and FSCAA (C6). Multiple regression analysis showed that FCSAA (C6), SFCSAR (C6), SFCSAR (C4), and EF were significant predictors of postoperative CSD. ROC curve analysis showed that the optimal cutoff points were 18.405, 2.95, 4.47, and 11.96.

CONCLUSIONS

The present study found that preoperative extension dysfunction of CPEs, asymmetry at the C6 level cervical extensors, and cervical extensor CSAs without fatty infiltration at the C4 and C6 levels were associated with cervical sagittal imbalance after modified laminoplasty. These factors can be considered when future spine surgeons formulate surgical plans.

Evaluating a paradigm shift from anterior decompression and fusion to muscle-preserving selective laminectomy: a single-center study of degenerative cervical myelopathy

OBJECTIVE

Muscle-preserving selective laminectomy (SL) is an alternative to conventional decompression surgery in patients with degenerative cervical myelopathy (DCM). It is less invasive, preserves the extensor musculature, and maintains the range of motion of the cervical spine. Therefore, the preferred treatment for DCM at the authors' institution has changed from anterior decompression and fusion (ADF), including anterior cervical discectomy and fusion (ACDF) and anterior cervical corpectomy and fusion (ACCF), toward SL. The aim of this study was to evaluate surgical outcomes before and after this paradigm shift with patient-reported outcome measures (PROMs), complications, reoperations, and cost-effectiveness.

METHODS

This study was a retrospective register-based cohort study. All patients with DCM who underwent ADF or SL at the authors' institution from 2008 to 2019 were reviewed. Using ANCOVA, changes in PROMs from baseline to the 2-year follow-up were compared between the two groups, adjusting for clinicodemographic parameters, baseline PROMs, number of decompressed levels, and MRI measurements (C2-7 Cobb angle, C2-7 sagittal vertical axis [SVA], and modified K-line interval [mK-line INT]). The PROMs, including the European Myelopathy Score (EMS), the Neck Disability Index (NDI), and the EQ-5D, were collected from the national Swedish Spine Register. Complications, reoperations, and in-hospital treatment costs were also compared between the two groups.

RESULTS

Ninety patients (mean age 60.7 years, 51 men [57%]) were included in the ADF group and 63 patients (mean age 68.8 years, 41 men [65%]) in the SL group. The ADF and SL groups had similar PROMs at baseline. The preoperative MR images showed similar C2-7 Cobb angles (10.7° [ADF] vs 14.1° [SL], p = 0.12) and mK-line INTs (4.08 vs 4.88 mm, p = 0.07), but different C2-7 SVA values (16.2 vs 19.3 mm, p = 0.04). The comparison of ANCOVA-adjusted mean changes in PROMs from baseline to the 2-year follow-up presented no significant differences between the groups (EMS, p = 0.901; NDI, p = 0.639; EQ-5D, p = 0.378; and EQ-5D health, p = 0.418). The overall complication rate was twice as high in the ADF group (22.2% vs 9.5%, p = 0.049), while the reoperation rate was comparable (16.7% vs 7.9%, p = 0.146). The average in-hospital treatment cost per patient was $6617 (USD) for SL, $7046 for ACDF, and $12,000 for ACCF.

CONCLUSIONS

SL provides similar PROMs after 2 years, a significantly lower complication rate, and better cost-effectiveness compared with ADF.

A comparative study of surgical outcomes between anterior cervical discectomy with fusion and selective laminoplasty for cervical spondylotic myelopathy

BACKGROUND

Few studies have directly compared anterior and posterior surgical approaches in cervical spondylotic myelopathy (CSM) patients with short-segment disease. We aimed to examine and compare surgical outcomes of anterior cervical discectomy with fusion (ACDF) and selective laminoplasty (S-LAMP) in CSM patients with 1- or 2-level disease.

METHODS

Forty-six patients, who received surgeries for CSM, were prospectively investigated; 24 underwent ACDF and 22 underwent S-LAMP. Average follow-up was 3.5 years. The following pre- and postoperative radiographic measurements were recorded: (1) C2-7 angle, (2) local angle (lordotic Cobb angle at operative level), (3) cervical sagittal vertical axis (SVA) (center of gravity of the head-C7 SVA), and (4) C7 slope. Outcomes were evaluated using the Japanese Orthopedic Association scoring system for cervical myelopathy (C-JOA score), neck pain visual analog scale, and neck disability index (NDI).

RESULTS

There were no significant differences in patient demographics between the two groups. Postoperatively, C2-7 angle, local angle, cervical SVA, C7 slope, C-JOA score, and neck pain and NDI scores were not significantly different between the two groups; however, the recovery rate of the C-JOA score was superior in the ACDF group (57.5%) compared to the S-LAMP group (42.1%). The recovery rate of the C-JOA score in the local lordosis subgroup (local angle ≥ 0°) showed no significant difference between the two surgical groups. However, in the local kyphosis subgroup (local angle < 0°), C-JOA score recovery rate was worse after S-LAMP (20.4%) than ACDF (57.9%); local angle also worsened postoperatively after S-LAMP.

CONCLUSIONS

In patients with local lordosis at the segments of cervical spondylosis and spinal cord compression, S-LAMP showed equivalent surgical outcomes (neurological recovery, neck pain and NDI scores, and cervical alignment) to ACDF. However, in patients with local kyphosis, S-LAMP worsened the kyphosis and resulted in worse neurological recovery.

Impact of C3 Involvement on Postoperative Kyphosis Following Cervical Laminoplasty: A Comparison Between High and Low T1 Slope

BACKGROUND

The goal of the present study was to investigate the impact of C3 involvement on the postoperative kyphosis following cervical laminoplasty in patients with high and low T1S.

METHODS

The data from ossification of the posterior longitudinal ligament patients who had undergone laminoplasty between January 2016 and December 2019 were retrospectively reviewed. Patients were divided into low-and high-T1S groups according to preoperative T1S, and the postoperative alignment change was compared between the groups. The relationships between postoperative cervical kyphosis and preoperative variables, including gender, C3 laminoplasty, T1S, cervical lordosis (CL), C2-7 Sagittal Vertical Axis, and T1S minus CL (T1S-CL) were investigated.

RESULTS

Eighty-six patients were divided into 2 groups above and below median preoperative T1S (23.70). There were thirty-three patients (38.3%) in low-T1S group and fifty-three patients (61.7%) in high-T1S group. Twenty-three patients (26.7%) were performed with C3 involved laminoplasty. C3 laminoplasty (odds ratio [OR], 9.67; 2.82-33.16; P = 0.000), high T1S (OR, 4.89; 1.54-15.49; P = 0.007), and mismatched T1S-CL (OR, 5.96; 1.83-19.43; P = 0.003) were significantly associated with postoperative kyphosis. In high-T1S group, the loss of CL was significant (P = 0.017) when C3 laminoplasty was performed, whereas, in low-T1S group, the C3 laminoplasty did not show the statistically significant difference. (P = 0.194).

CONCLUSIONS

C3 laminoplasty, mismatched T1S-CL, and high T1S were found to increase the risk of postoperative kyphosis following cervical laminoplasty. Patients with high T1 slope tended to exhibit a greater loss of CL when the laminoplasty was performed extending to C3 segment.

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 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.

K-line (-) in the neck-flexed position negatively affects surgical outcome of expansive open-door laminoplasty for cervical spondylotic myelopathy

BACKGROUND

The K-line in the neck-flexed position (FK-line) on radiography reflects dynamic factors and cervical alignment. Although the FK-line has been reported to affect the neurological recovery after muscle-preserving selective laminectomy for cervical spondylotic myelopathy (CSM), its influence on surgical outcomes after expansive open-door laminoplasty (ELAP) has not been investigated.

METHODS

We reviewed the surgical outcomes in 81 patients with multilevel CSM who underwent C4-C6 ELAP combined with C3 and C7 partial laminectomy using a laminoplasty plate and were followed up for at least 2 years. We defined the K-line (-) as some portion of a bony spur or the vertebral body crossing the FK-line, whereas the FK-line (+) was defined as that never crossing the FK-line. Patients were divided into the FK-line (+) (n = 61) and FK-line (-) groups (n = 20), and the surgical outcomes were compared between the groups. A multivariate analysis was performed to identify the factors that influenced the neurological outcomes.

RESULTS

The FK-line (-) group had a smaller C2-C7 angle, smaller C7 slope, greater postoperative increase in the C2-C7 sagittal vertical axis, greater kyphosis in cervical flexion and less lordosis in cervical extension, and higher incidence of postoperative residual spinal cord compression. The preoperative-to-postoperative changes in the Japanese Orthopedic Association (JOA) score and JOA score recovery rate (RR) were lower in the FK-line (-) group. The multiple linear regression analysis revealed that the K-line (-) (β = -0.327, P = 0.011) and high signal intensity (SI) changes on T2-weighted imaging (WI) combined with the low SI changes on T1-WI in the spinal cord (β = -0.320, P = 0.013) negatively affected the JOA score RR.

CONCLUSIONS

The FK-line can be used for patients with CSM as a simple indicator of neurological outcomes after ELAP.

Atlantoaxial stenosis after muscle-preserving selective laminectomy

There are few reports of degenerative atlantoaxial stenosis and new stenosis after cervical decompression. We experienced four cases of atlantoaxial stenosis after muscle-preserving selective laminectomy. We compared these four cases with no stenosis cases after long-term follow-up of selective laminectomy, as well as healthy subjects. A total of 1205 patients who underwent muscle-preserving selective laminectomy due to cervical disorders were included in this study. Postoperative atlantoaxial stenosis, which needed decompression, appeared in 4 cases, and 30 patients did not have radiological stenosis for more than 10 years after surgery. Twenty healthy volunteers were also used as controls. The radiographic parameters measured were C2-C7 angle, C2-C7 sagittal vertical axis (SVA), C2 slope, C7 slope, C2-C5 angle, C5-C7 angle, C1-C2 angle, and atlantodental interval (ADI). We measured the anterior-posterior (AP) diameters of the spinal cord (SC) and dural tube (Dura) at C1/C2 with sagittal MRI. In the cases of atlantoaxial stenosis, the AP of SC and Dura at C1/C2 were smaller preoperatively, and the residual space for SC (SAC) was also smaller. The preoperative ADI was significantly higher in patients with atlantoaxial stenosis, suggesting preoperative instability at C1/C2. Analysis of the ROC curve showed that patients with a preoperative SAC of less than 3.6 mm and an ADI of more than 1.35 mm were more likely to develop postoperative atlantoaxial stenosis. When we perform a muscle-preserving selective laminectomy, decompression of C1/C2 is suggested when the SAC at C1/C2 is less than 3.6 mm and the ADI is more than 1.35 mm.

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.

Effect of Minimally Invasive Selective Laminectomy for Cervical Spondylotic Myelopathy on Degenerative Spondylolisthesis

STUDY DESIGN

Retrospective analysis of prospectively collected observational data.

OBJECTIVE

This study aimed to evaluate the slippage, sagittal alignment, and range of motion (ROM) after selective laminectomy (SL) in patients who had cervical spondylotic myelopathy (CSM) with degenerative spondylolisthesis (DS).

SUMMARY OF BACKGROUND DATA

Clinical outcomes have been reported for both decompression and fusion surgeries for DS of the lumbar spine. However, only a few reports have examined cervical spine spondylolisthesis.

MATERIALS AND METHODS

This study included 178 patients who underwent SL for CSM. Those with ossification of the posterior longitudinal ligament were excluded. Slippage >2 mm was defined as spondylolisthesis, and spondylolisthesis progression was defined as an additional displacement >2 mm on a neutral radiograph. The slippage, translational motion, C2-C7 angle, local kyphosis, and ROM were examined before and ≥2 years after surgery. Radiologic parameters were evaluated according to the slip direction and the number of laminae removed.

RESULTS

DS was observed in 29 patients (16.3%); 24 patients, comprising 9 and 15 in the anterolisthesis and retrolisthesis groups, respectively, were successfully followed up for more than 2 years. Preoperative and postoperative radiologic changes in slippage, translational motion, C2-C7 angle, local kyphosis, and ROM were not remarkable in either group regardless of the number of laminae removed. Revision surgery for the progression of DS and alignment deterioration was not required in any patient of either group.

CONCLUSIONS

SL does not affect DS, sagittal alignment, or ROM irrespective of the slip direction and the number of laminae removed, even after >2 years after surgery. Given the preservation of the posterior elements, SL may be an effective treatment for CSM with DS.

LEVEL OF EVIDENCE

Level IV.

Surgical and Functional Outcomes of Expansive Open-Door Laminoplasty for Patients With Mild Kyphotic Cervical Alignment

Objective

To evaluate the cervical dynamics, neurological function, pain, and quality of life in patients with mild cervical kyphotic alignment who underwent expansive unilateral open-door laminoplasty (ELAP).

Methods

In this retrospective single-center study, we reviewed the surgical outcomes of 80 patients with cervical spondylotic myelopathy who were followed for at least 2 years. The patients were categorized into the preoperative kyphotic group (C2–7 angle < 0°) and nonkyphotic group (angle ≥ 0°). We compared clinical information, radiographic parameters, Japanese Orthopaedic Association Cervical Myelopathy Evaluation Questionnaire (JOACMEQ) scores, and cervical Japanese Orthopaedic Association (JOA) scores between the groups.

Results

The kyphotic and nonkyphotic groups comprised 17 and 63 patients, respectively. The preoperative C2–7 angles were -3.7° in the kyphotic group and 15.4° in the nonkyphotic group (p<0.01). In the kyphotic group, kyphotic alignment improved to lordosis at the final follow-up (2.6°, p=0.01). The preoperative (16.4° vs. 24.1°, p<0.01) and final-follow-up (17.8° vs. 24.5°, p<0.01) C7 slopes were significantly smaller in the kyphotic group. ELAP reduced pain in the arms or hands (p=0.02) and improved the JOA scores (p<0.01) in the kyphotic group. Patient-reported outcomes assessed using the JOACMEQ showed comparable effective rates in both groups.

Conclusion

Patients with mild cervical kyphosis showed smaller C7 slopes as a compensatory mechanism. Kyphotic angles significantly improved to lordosis after ELAP, resulting in favorable clinical outcomes. ELAP is a useful surgical option for patients even if they present mild kyphotic cervical angles.

Laminectomy alone versus laminectomy with fusion for degenerative cervical myelopathy: a long-term study of a national cohort

PURPOSE

To compare patient-reported 5-year clinical outcomes between laminectomy alone versus laminectomy with instrumented fusion in patients with degenerative cervical myelopathy in a population-based cohort.

METHODS

All patients in the national Swedish Spine Register (Swespine) from January 2006 until March 2019, with degenerative cervical myelopathy, were assessed. Multiple imputation and propensity score matching based on clinicodemographic and radiographic parameters were used to compare patients treated with laminectomy alone with patients treated with laminectomy plus posterior-lateral instrumented fusion. The primary outcome measure was the European Myelopathy Score, a validated patient-reported outcome measure. The scale ranges from 5 to 18, with lower scores reflecting more severe myelopathy.

RESULTS

Among 967 eligible patients, 717 (74%) patients were included. Laminectomy alone was performed on 412 patients (mean age 68 years; 149 women [36%]), whereas instrumented fusion was added for 305 patients (mean age 68 years; 119 women [39%]). After imputation, the propensity for smoking, worse myelopathy scores, spondylolisthesis, and kyphosis was slightly higher in the fusion group. After imputation and propensity score matching, there were on average 212 pairs patients with a 5-year follow-up in each group. There were no important differences in patient-reported clinical outcomes between the methods after 5 years. Due to longer hospitalization times and implant-related costs, the mean cost increase per instrumented patient was approximately $4700 US.

CONCLUSIONS

Instrumented fusions generated higher costs and were not associated with superior long-term clinical outcomes. These findings are based on a national cohort and can thus be regarded as generalizable.

Etiology and treatment of cervical kyphosis: state of the art review-a narrative review

Objective

To provide state of the art review regarding cervical kyphosis.

Background

Cervical spine kyphosis has been increasingly common due to the growing elderly population. Clinicians should comprehensively understand its symptoms, biomechanics, etiology, radiographic evaluation, classification, and treatment options and complications of each treatment. Comprehensive review will help clinicians improve the management for patients with cervical kyphosis.

Methods

The available literature relevant to cervical kyphosis was reviewed. PubMed, Medline, OVID, EMBASE, and Cochrane were used to review the literature.

Conclusions

This article summarizes current concepts regarding etiology, evaluation, surgical treatment, complications and outcomes of cervical kyphosis. Major etiologies of cervical kyphosis include degenerative, post-laminectomy, and ankylosing spondylitis. Clinical presentations include neck pain, myelopathy, radiculopathy, and problems with horizontal gaze, swallowing and breathing. Cervical lordosis, C2-7 sagittal vertical axis, chin-brow to vertical angle, and T1 slope should be evaluated from upright lateral 36-inch film. The most widely used classification system includes a deformity descriptor and 5 modifiers. A deformity descriptor provides a basic grouping of the deformity consisting of five types, cervical, cervicothoracic, thoracic, coronal cervical deformity, and cranio-vertebral junction deformity. The 5 modifiers include C2-7 sagittal vertical axis, chin-brow to vertical angle, T1 slope minus cervical lordosis, myelopathy based on modified Japanese Orthopaedic Association score, and SRS-Schwab classification for thoracolumbar deformity. Current treatment options include anterior discectomy and fusion, anterior osteotomy, Smith-Peterson osteotomy, pedicle subtraction osteotomy, or a combination of these based on careful preoperative evaluation.

Relationship between cervical curvature and spinal cord drift distance after laminectomy via lateral mass screw fixation and its effect on clinical efficacy

BACKGROUND

Laminectomy with lateral mass screw fixation (LCS) is considered an effective surgical procedure for cervical spondylotic myelopathy. However, varying degrees of loss of the cervical curvature were noted in some patients postoperatively. The aim of this study was to observe the relationship between cervical curvature and spinal drift distance after LCS and to determine its effect on neurological function, axial symptoms, and C5 palsy.

METHODS

A total of 117 consecutive cervical spondylotic myelopathy patients with normal cervical curvature underwent LCS from April 2015 to May 2017 in our institution. Of these patients, 90 patients who accepted to undergo an integrated follow-up were enrolled in this study. The patients were divided into 3 groups based on their postoperative cervical curvature. In group A (28 patients), the cervical curvature became straight postoperatively (0°≤cervical spine angle≤5°); in group B (36 patients), the cervical curvature decreased (5°<cervical spine angle≤16.5°); and in group C (26 patients), the cervical curvature remained normal (cervical spine angle>16.5°). Spinal drift distance, neurological recovery, axial symptoms, and C5 palsy in the patients were recorded and analyzed.

RESULTS

Postoperative measurements showed that there was no significant difference in laminectomy width between the groups (P > .05). The cervical spine angle was 2.7° ± 0.5° in group A, 11.2° ± 2.6° in group B, and 20.8° ± 4.1° in group C (P < .05), while the spinal drift distance was 1.2 ± 0.2 mm, 1.8 ± 0.4 mm, and 3.0 ± 0.5 mm, respectively (P < .05). The postoperative Japanese Orthopedic Association score was significantly increased in all groups (P < .05), and there was no significant difference between the groups at different time points (P > .05). However, significant differences were noted between the groups in axial symptoms (P < .05), which were analyzed via the visual analog scale score. The occurrence of C5 palsy in groups A, B, and C was 7.1% (2/28), 8.3% (3/36), and 11.5% (3/26), respectively (P > .05).

CONCLUSION

In LCS, the cervical curvature should be maintained at the normal angle to obtain a good spinal cord drift distance and a lower incidence of axial symptoms.

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.

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 Extensor Muscles Play the Role on Malalignment of Cervical Spine: A Case Control Study With Surface Electromyography Assessment

STUDY DESIGN

A case control study.

OBJECTIVE

The aim of this study was to identify the potential impact of cervical spine malalignment on muscle parameters.

SUMMARY OF BACKGROUND DATA

Muscular factors are associated with cervical alignment. Nevertheless, only muscle dimensions or imaging changes have been evaluated, function of cervical muscles has scarcely been investigated.

METHODS

Thirty-four patients diagnosed as cervical spine degeneration associated with cervical malalignment and 32 control subjects were included in this case control study. Visual analogue scale (VAS) and the neck disability index (NDI) were used. The sagittal alignment parameters and cervical range of motion (ROM) were measured on cervical spine lateral radiographs, included C2-C7 lordosis, C2-C7 sagittal vertical axis (C2-C7 SVA), cervical gravity-sagittal vertical axis (CG-SVA), T1-Slope, and spinal canal angle (SCA). Surface electromyography (SEMG)-based flexion-relaxation ratio (FRR) was measured.

RESULTS

The result showed VAS score of the neck significantly lower in controls (P<0.05), C2-C7 lordosis, C2-C7 SVA, CG-SVA, T1-Slope and ROM showed significantly different (P<0.001) between malalignment group and control group, FRR of splenius capitis (FRRSpl) and upper trapezius (FRRUTr) of the malalignment group were lower than in the control group, which correlated well with NDI (rSpl = -0.181 rUTr = -0.275), FRRSpl correlated well with VAS (rSpl = -0.177). FRRSpl correlated strongly with C2-C7 SVA (r = 0.30), CG-SVA (r = 0.32), T1-Slope (r = 0.17), ROM (r = 0.19), FRRUTr correlated with C2-C7 lordosis (r = -0.23), CG-SVA (r = 0.19), T1-Slope (r = 0.28), ROM (r = 0.23).

CONCLUSION

Cervical malalignment patients had more tensional posterior cervical muscle and poor muscle functions. CG-SVA showed advantages in evaluating cervical malalignment.Level of Evidence: 3.

Does K-line (-) in the Neck-flexed Position Predict Surgical Outcome of Cervical Spondylotic Myelopathy?: Results of a Multivariate Analysis After Muscle-preserving Selective Laminectomy

STUDY DESIGN

A retrospective single-center study.

OBJECTIVE

The aim of this study was to investigate the influence of the K-line in the neck-flexed position (flexion K-line) on the surgical outcome after muscle-preserving selective laminectomy (SL) for cervical spondylotic myelopathy (CSM).

SUMMARY OF BACKGROUND DATA

Development of CSM is associated with dynamic factors and cervical alignment. The flexion K-line, which reflects both dynamic and alignment factors, provides an indicator of surgical outcome after posterior decompression surgery for patients with ossification of the posterior longitudinal ligament. However, the value of the flexion K-line for patients with CSM has not been evaluated.

METHODS

Our study group included 159 patients treated with SL for CSM. Patients were divided into a flexion K-line (+) group and a flexion K-line (-) group. The influence of the flexion K-line on radiological and surgical outcomes was analyzed, with multivariate analysis conducted to identify factors affecting the surgical outcome.

RESULTS

Patients in the flexion K-line (-) group were younger (P = 0.003), had a less lordotic cervical alignment (pre-and postoperatively, P < 0.001), a smaller C7 slope (pre-and postoperatively, P < 0.001), and a greater mismatch between the C7 slope and the C2-C7 angle (preoperatively, P = 0.047; postoperatively, P = 0.001). The postoperative increase in Japanese Orthopedic Association (JOA) score and the JOA score recovery rate (RR) were lower for the flexion K-line (-) than for the K-line (+) group (P < 0.001 and P < 0.001, respectively). On multivariate regression analysis, the flexion K-line (-) (β = -0.282, P < 0.001), high signal intensity (SI) changes on T2-weighted image (WI) combined with low SI changes on T1-WI in the spinal cord (β = -0.266, P < 0.001), and older age (β= -0.248, P = 0.001) were predictive of a lower JOA score RR.

CONCLUSION

The flexion K-line may be a useful predictor of surgical outcomes after SL in patients with CSM.

LEVEL OF EVIDENCE

4.

C3 laminectomy combined with modified unilateral laminoplasty and in situ reconstruction of the midline structures maintained cervical sagittal balance: a retrospective matched-pair case-control study

BACKGROUND CONTEXT

Open-door laminoplasty often results in postoperative complications such as loss of cervical lordosis, limitations of cervical motion, and axial symptoms. However, current modified laminoplasty techniques such as muscle-sparing type or spinous process splitting technique are not as effective as expected.

PURPOSE

To evaluate the radiological and clinical outcomes of C3 laminectomy combined with modified unilateral laminoplasty (preservation of posterior muscle-ligament complex and reconstruction of the midline structures) versus traditional open door laminoplasty in treating cervical spondylotic myelopathy or ossification of the posterior longitudinal ligament.

STUDY DESIGN

Retrospective case-control study.

PATIENT SAMPLE

One hundred and eleven patients with multilevel cord compression and myelopathic symptoms.

OUTCOME MEASURES

The outcome parameters were operation time, blood loss volume, complications, osseous fusion status, C0-C2 and C2-C7 Cobb angles, T1 slope, cervical sagittal vertical axis (cSVA), cervical curvature index (CCI), range of motion (ROM), cross-sectional area (CSA) of the semispinalis cervicis, axial symptoms, visual analog scale (VAS) score, Japanese Orthopedic Association (JOA) score, and neck disability index (NDI).

METHODS

We matched 37 patients who underwent modified laminoplasty with 74 patients treated by traditional open door laminoplasty (ratio, 1:2) according to age, sex, body mass index, compromised level, and radiographic characteristics. Preoperative and postoperative cervical parameters, namely, the C2-C7 Cobb angle, ROM, and CCI were measured on X-ray films. The CSA of the semispinalis cervicis was assessed on magnetic resonance images, and osseous fusion status of the hinge side and the osteotomy site was evaluated by computed tomography. We used the JOA and VAS scores, and the NDI to evaluate clinical outcomes.

RESULTS

The average follow-up period in the modified group was 24.1 months (range, 18-37 months) compared with 24.7 months (range, 18-38 months) in the control group. At the final follow-up, C0-C2 Cobb angle, T1 slope, and cSVA increased in the control group and were unchanged in the modified group. The C2-C7 Cobb angle decreased significantly in the control group and did not change in the modified group. ROM and CCI loss rate did not change in the modified group but decreased significantly in the control group. The CSA loss in the semispinalis cervicis was 222.90±79.56 mm² in the control group and 49.11±75.93 mm² in the modified group, with a significant difference (p<.001). The final CSA of the semispinalis cervicis at C2 and C4-C7 levels showed no significant difference in the modified group and decreased significantly in the control group compared with preoperation. Changes in the C2-C7 Cobb angle and cSVA were both correlated with the CSA loss of the semispinalis cervicis (r=0.282, p=.003; r=0.267, p=.005, respectively). Moreover, the CSA loss of the semispinalis cervicis also correlated with the CCI loss rate and the changes in ROM (r=0.312, p=.001; r=0.287, p=.002, respectively). Clinical outcomes such as VAS and NDI scores, improved significantly more in the modified group versus the controls (p<.001 and p=.005, respectively), while JOA scores improved similarly in both groups (p=.132). The incidence of axial symptoms was significantly lower in the modified group versus controls (5.4% vs 9.5%, respectively; p=.023).

CONCLUSIONS

C3 laminectomy combined with modified unilateral laminoplasty is effective for treating patients with multilevel cord compression. This modified technique reconstructs the midline structures and may lead to improved alignment and less axial pain.

K-line (-) in the neck-flexed position affects surgical outcomes in patients with ossification of the posterior longitudinal ligament after muscle-preserving selective laminectomy

BACKGROUND

Posterior cervical decompression results in favorable outcomes for K-line (+) ossification of the posterior longitudinal ligament (OPLL) patients. However, even for patients with K-line (+) in the neck neutral position, K-line (-) in the neck-flexed position (flexion K-line (-)) may affect surgical outcomes. We investigated the influence of flexion K-line (-) on surgical outcomes after muscle-preserving selective laminectomy using multivariate analysis.

METHODS

This study involved 113 OPLL patients with K-line (+) in the neck neutral position who underwent muscle-preserving selective laminectomy. Patients were divided into flexion K-line (+) (n = 90) and flexion K-line (-) (n = 23) groups. We analyzed the influence of a flexion K-line (-) on radiological and surgical outcomes. We conducted a multivariate analysis to analyze the factors affecting surgical outcomes.

RESULTS

The patients with a flexion K-line (-) had a larger C2-C7 sagittal vertical axis (preoperatively, P = 0.042; postoperatively, P = 0.021), narrower postoperative clearance of the spinal cord (P = 0.003), a smaller proportion of segmental-type OPLL (P < 0.001), and a greater OPLL occupancy ratio (P < 0.001). The recovery rate measured by the Japanese Orthopedic Association (JOA) score was poorer in patients with a flexion K-line (-) (17.6 ± 32.2%) than in those with a flexion K-line (+) (35.3 ± 29.5%) (P = 0.013). Multiple linear regression analysis revealed that the flexion K-line (-) affected the recovery rate of the JOA score (β = -0.233, P = 0.013).

CONCLUSIONS

Even for patients with K-line (+) OPLL, the flexion K-line (-) affects surgical outcomes. The flexion K-line (-) is a useful predictor of poor surgical outcomes after posterior decompression surgery.

Surgical Outcomes in Selective Laminectomy and Conventional Double-Door Laminoplasty for Cervical Spondylotic Myelopathy

Several postoperative problems have been reported in conventional cervical laminoplasty (C-LAMP), such as loss of cervical curvature, sagittal imbalance, and loss of range of motion (ROM). Selective laminectomy (S-LAM) is a less invasive procedure that may prevent the problems associated with conventional C-LAMP. In this study, the authors prospectively compared neurological outcomes and radiological parameters in C-LAMP and S-LAM for the treatment of cervical spondylotic myelopathy. Fifty-three patients were enrolled, with 25 patients receiving conventional double-door C-LAMP and 28 patients receiving S-LAM. Measured outcomes included operative time, intraoperative blood loss, Japanese Orthopaedic Association score for neurological recovery, cervical sagittal alignment at C2-7, cervical sagittal vertical axis from occiput to C7, C7 slope, and cervical ROM at C2-7. No difference was found in operative time, whereas intraoperative blood loss was significantly less in the S-LAM group (P<.05). No significant difference in neurological recovery was found between the 2 groups. The postoperative C2-7 angle was significantly smaller (P<.05) and cervical sagittal vertical axis greater (P<.01) in the C-LAMP group. Postoperative ROM at C2-7 was greater (P<.01) in the S-LAM group. In the CLAMP group, postoperative kyphotic change was greater in patients with high C7 slope. However, in the S-LAM group, postoperative sagittal alignment was preserved even in patients with high C7 slope. Postoperative cervical alignment, sagittal balance, and cervical ROM were better preserved in the S-LAM group compared with the C-LAMP group. Selective laminectomy is an effective, minimally invasive method for cervical spondylotic myelopathy with spinal cord compression at limited levels. [Orthopedics. 2020;43(4);e311-e315.].

Factors associated with postoperative axial symptom after expansive open-door laminoplasty: retrospective study using multivariable analysis

PURPOSE

The aim of the present study was to investigate the factors associated with axial symptom using multivariable analysis.

METHODS

The authors retrospectively assessed 249 patients treated by open-door laminoplasty. The patients were classified into two groups: axial symptom and no axial symptom group. The possible factors included demographic variables (age, sex, BMI, smoking, heart disease, diabetes, preoperative neck pain, preoperative JOA scores, preoperative NDI, course of disease and pathogenesis) and surgical and radiological variables [operation time, intraoperative blood loss, collar wear time, preoperative cervical curvature, postoperative cervical curvature, T1 slope, preoperative and postoperative C2 sagittal vertical axis (C2 SVA)].

RESULTS

The prevalence of axial symptom was 34.9% (89/249). The collar wear time, preoperative and postoperative C2 SVA were risk factors for axial symptom. A cutoff value of 22.6 mm for preoperative C2 SVA and 3.5 weeks for collar wear time predicted the development of axial symptom.

CONCLUSIONS

The longer collar wear time, larger preoperative and postoperative C2 SVA were positively correlated with the higher incidence of axial symptom.

Sagittal Alignment After Laminectomy Without Fusion as Treatment for Cervical Spondylotic Myelopathy: Follow-up of Minimum 4 Years Postoperatively

OBJECTIVES

The aims of this study were to evaluate the incidence of sagittal malalignment including kyphosis following cervical laminectomy without fusion as treatment for cervical spondylotic myelopathy and to assess any correlation between malalignment and clinical outcome.

STUDY DESIGN

Retrospective cohort study.

METHODS

In all, 60 patients were followed up with conventional radiography at an average of 8 years postoperatively. The cervical lordosis (C2-C7 Cobb angle), C2-C7 sagittal vertical axis (cSVA) and C7 slope were measured on both preoperative and postoperative images. Patients completed a questionnaire covering Neck Disability Index (NDI), visual analogue scale for neck pain, and general health (EQ-5D).

RESULTS

Mean C2-C7 Cobb angle was 8.6° (SD 9.0) preoperatively, 3.4° (10.7) postoperatively and 9.6° (14.5) at follow-up. Ultimately, 3 patients showed >20° cervical kyphosis. Mean cSVA was 16.3 mm (SD 10.2) preoperatively, 20.6 mm (11.8) postoperatively, and 31.6 mm (11.8) at follow-up. Mean C7 slope was 20.4° (SD 8.9) preoperatively, 18.4° (9.4) postoperatively, and 32.6° (10.2) at follow-up. The preoperative to follow-up increase in cSVA and C7 slope was statistically significant (both P < .0001), but not for cervical lordosis. The preoperative to follow-up change in cSVA correlated moderately with preoperative cSVA (r = 0.43, P = .002), as did the corresponding findings regarding C7 slope (r = 0.52, P = .0001). A comparison of radiographic measurements with clinical outcome showed no strong correlations.

CONCLUSIONS

No preoperative to follow-up change in cervical lordosis was found in this group; 5.0% developed >20° kyphosis. No clear correlation between sagittal alignment and clinical outcome was shown.

Correlation between C7 slope and cervical lordosis in patients after expansive open-door laminoplasty

Purpose of the article: To investigate the correlation between C₇ slope and cervical lordosis in patients after expansive open-door laminoplasty (EOLP).Material and methods: We retrospectively analyzed 57 patients who underwent EOLP between June 2013 and January 2017 in the Department of Spinal Surgery of our hospital. The operation time, intraoperative blood loss and follow-up time were recorded. The C₇ slope, C_2-7 sagittal vertical axis, and C_2-7 Cobb angle were measured anteroposterior radiograph of the cervical spine preoperatively and postoperatively. All patients were divided into two groups according to the preoperative C₇ slope (C₇ slope ≤20° group and C₇ slope >20° group).Results: The amount of intraoperative bleeding was 220.2 ± 180.9ml, and the operation time was 143.4 ± 51.2min. The average follow-up time was 24.9 ± 10.3months (range12-48 months). The C_2-7 Cobb angle was 13.49 ± 10.46°at the final follow-up, which was significantly lower than that preoperatively (p = .026). But, The C₇ slope and C_2-7 sagittal vertical axis showed no significant difference between preoperatively and postoperatively. Preoperative and postoperative C₇ slope and C_2-7 Cobb angle were positively correlated to age and significant difference was observed. In the group of C₇ slope >20°, significant difference was observed in term of the change of the C_2-7 Cobb angle and C_2-7SVA postoperatively (p = .009 and p= .020). However, there was no statistically significant difference detected in these two parameters in the group of C₇ slope ≤20°.Conclusion: This study indicated that C₇ slope could be used as an indicator of the change in the curvature of the cervical spine after EOLP. The loss of cervical curvature after surgery was prone to occur when C₇ slope was greater than 20°, which should be noted in clinical practice.

Extensor muscle-preserving laminectomy in treating multilevel cervical spondylotic myelopathy compared with laminoplasty

Background

Laminectomy and laminoplasty are popularly used in posterior cervical spine surgery but still have involved complications. We aimed to compare the clinical outcomes of microscope-assisted extensor muscle-preserving laminectomy (MA-EMPL) and open-door laminoplasty (ODLP) in treating multilevel cervical spondylotic myelopathy (MCSM).

Methods

A prospective study was designed to enroll twenty patients with MCSM underwent MA-EMPL, and recruit twenty-four patients with MCSM received ODLP (control). Radiographic measurements, outcome indicators including Japanese Orthopedic Association (JOA) score and visual analogue score (VAS) were used to evaluate technical effectiveness. Surgical complications were documented to assess technical safety.

Results

Postoperative cervical curvature index and range of neck motion (ROM) were not significantly changed except ROM in ODLP group. Postoperative JOA score and VAS in both groups showed improvements at final follow-up. There was no statistical difference in postoperative neurological recovery rates between two groups (67.6%±17.8% vs. 70.15%±19.6%, P=0.632). However, VAS was significantly lower at postoperative 1 month in MA-EMPL group compared with ODLP group (P<0.001). The incidences of C5 palsy were 0 vs. 16.7% between MA-EMPL group and ODLP group. There was no axial symptom occurred in MA-EMPL group while six patients in ODLP group (0 vs. 25%, P=0.049). In addition, the mean blood loss and hospital stay were lesser in MA-EMPL group compared with ODLP group (P<0.001, P=0.002, respectively).

Conclusions

MA-EMPL is an effective, safe and minimally invasive method in treatment of MCSM. Compared with ODLP, MA-EMPL has advantage to decrease intraoperative blood loss, hospital stay, postoperative VAS and axial symptom, as well as preserve postoperative ROM.

Posterior Cervical Muscle-Preserving Interspinous Process Approach and Decompression: More Minimally Invasive and Modified Shiraishi's Selective Laminectomy

OBJECTIVE

The cervical extensor musculature is important in cases of neck pain and loss of cervical lordosis after laminoplasty. Therefore, various surgical methods have been developed to preserve the muscle during laminoplasty. We have developed a posterior cervical muscle-preserving interspinous process (MIS) approach and decompression method. We have described the operation details and clinical outcomes of selected patients who have undergone this procedure.

METHODS

The MIS approach and decompression method were performed in 20 consecutive patients who had only required central decompression for cervical stenosis. This procedure includes an approach to the interspinous space that is similar to Shiraishi's method but includes decompression without fracturing the spina bifida.

RESULTS

The patients had no complications and did not require conversion to conventional laminoplasty. The mean operative time and mean blood loss was 53.0 minutes and 63.0 mL per level, respectively, and the mean hospital stay was 4.0 days. The mean preoperative and 3-month postoperative modified Japanese Orthopedic Association scores were 12.6 and 16.2, and the mean preoperative and 3-month postoperative neck disability index scores were 15.4 and 2.5, respectively. The postoperative neck visual analog scale score was 0.8. The mean preoperative and postoperative sagittal vertical axis was 1.6 and 1.8 cm, respectively. The mean loss of lordosis was 1.0°, and the mean cervical range of motion did not change from preoperatively to postoperatively.

CONCLUSIONS

The MIS approach and decompression method was less invasive than both conventional laminoplasty and Shiraishi's selective laminectomy. It is a safe and effective minimally invasive technique for central stenosis caused by cervical spondylotic myelopathy.

Ossified Posterior Longitudinal Ligament Existing at an Intervertebral Level Limits Compensatory Mechanism of Cervical Lordosis after Muscle-Preserving Selective Laminectomy

Introduction

As C7 slope increases, lordotic change of C2-C7 angle compensates for adjustments in cervical sagittal balance. However, ossification of the posterior longitudinal ligament (OPLL) may affect the compensatory mechanism of the cervical spine. This study aims to evaluate the impact of OPLL on cervical lordotic compensation after muscle-preserving selective laminectomy (SL).

Methods

This study involved 235 patients with cervical spondylotic myelopathy (CSM) and OPLL who underwent ≥ 3 consecutive levels of SL. OPLL was classified into continuous, segmental, mixed, or localized type on the basis of the criteria previously reported. In this study, based on the motion preservation at the intervertebral level, patients were divided into CSM (n = 114), OPLL segmental type (OPLL-S; n = 44), and other types of OPLL (OPLL-O; i.e., continuous, mixed, and localized; n = 77). The cervical sagittal alignment, degree of spinal cord decompression, and surgical outcomes were compared among the three groups.

Results

The OPLL-O group had a larger postoperative C7 slope (p = 0.020), larger pre- (p = 0.021) and postoperative (p = 0.001) C2-C7 sagittal vertical axis, and greater pre- (p = 0.034) and postoperative (p = 0.002) C7 slope minus C2-C7 angle. Narrower postoperative spinal cord clearance (PSCC) from OPLL (p < 0.001) and more residual spinal cord compression (p < 0.001) were observed in the OPLL-O group. Correlation between postoperative C7 slope minus C2-C7 angle and PSCC was detected (r = −0.238, p < 0.001). The recovery rate of the Japanese Orthopedic Association score was slightly lower in the OPLL-O group (p < 0.001), and it was correlated with postoperative residual spinal cord compression (r = −0.305, p < 0.001).

Conclusions

OPLL-O limits cervical lordotic compensation, resulting in cervical sagittal balance mismatch. It affects the degree of spinal cord decompression, which might be related to surgical outcome.

Influence of the Ratio of C2–C7 Cobb Angle to T1 Slope on Cervical Alignment After Laminoplasty

PURPOSE

To assess the relationship between the ratio of C2-C7 Cobb angle to T1 slope (CL/T1S) and cervical alignment changes after laminoplasty.

METHODS

78 consecutive patients with cervical myelopathy who underwent laminoplasty were enrolled. All patients with preoperative and follow-up cervical spine lateral x-ray images available for review were recruited in this study. Imaging data included C2-C7 Cobb angle, T1 slope, and cervical sagittal vertical axis (cSVA). All patients were classified into low-ratio group (bottom 25% of CL/T1S), fair-ratio group (middle 50% of CL/T1S), and high ratio group (top 25% of CL/T1S) according to CL/T1S ratio. The recovery rate was calculated based on the Japanese Orthopedic Association score.

RESULTS

The preoperative C2-C7 Cobb angle had significant correlations with the T1 slope (r = 0.528). Kyphotic alignment changes in the group with a high ratio of CL/T1S was greater than that of the other 2 groups (P < 0.001). The incidence of postoperative kyphosis in the group with a low ratio of CL/T1S was higher than that of the other 2 groups (P < 0.001). There was no postoperative kyphosis in the fair-ratio group. The surgical outcome in the low-ratio CL/T1S group and the high-ratio CL/T1S group was poorer than that in the fair-ratio CL/T1S group (P = 0.005).

CONCLUSIONS

The cervical alignment was kept well in the mid-range CL/T1S ratio group after laminoplasty. Patients with a high CL/T1S ratio were more likely to present with kyphotic alignment changes. Patients with a low CL/T1S ratio were more likely to have postoperative kyphosis.

Upper cervical lordosis compensates lower cervical kyphosis to maintain whole cervical lordosis after selective laminectomy

After lower-cervical-level spinal-cord tumor resection, compensatory upper cervical lordosis with lower cervical kyphosis was observed. However, no studies examined this compensation following posterior decompression surgery for cervical compressive myelopathy (CCM). The purpose of this study was to evaluate the compensatory mechanism after muscle-preserving selective laminectomy (SL) and to assess the clinical outcomes following such compensation. Enrolled in the study were 125 CCM patients who underwent C6 single-level SL, C5-C6 two-level SL, C4-C6 three-level SL, and C3-C6 four-level SL. Cervical spine lateral radiography was taken before surgery and during the final followup. The C2-C5, C5-C7, and C2-C7 angles were measured and presented respectively as the patients' "upper," "lower," and "whole" cervical alignments. Patients were divided into two groups according to their postoperative C5-C7 alignment changes. We then divided the C5-C7 kyphotic-change group according to the patients' postoperative C7 slope changes. Postoperative cervical sagittal balance and surgical outcomes were compared within the groups. Postoperative C5-C7 kyphotic change was compensated for by C2-C5 lordotic change, maintaining the preoperative C2-C7 angle. Although postoperative C5-C7 kyphotic change alone did not affect cervical sagittal balance or surgical outcomes, patients with C5-C7 kyphotic changes and C7 slope increases showed greater increases in the C2-C7 sagittal vertical axis and lower recovery rates in Japanese Orthopaedic Association scores. The patients' postoperative lower cervical kyphotic changes were compensated for by upper cervical lordotic changes. Despite this compensation, increases in patients' C7 slopes adversely affected sagittal balance and functional recovery.

Catastrophic Dropped Head Syndrome Requiring Multiple Reconstruction Surgeries after Cervical Laminoplasty

Introduction

Dropped head syndrome (DHS) after cervical laminoplasty (LAMP) is a rare complication, and no etiologies or surgical strategies have been reported. We present a patient who developed catastrophic DHS after LAMP despite having preoperative cervical lordosis that is known to be suitable for LAMP. We describe a hypothesis concerning the possible mechanism responsible for the DHS and a surgical strategy for relieving it.

Case Report

A 76-year-old woman underwent LAMP for cervical spondylotic myelopathy. She achieved satisfactory improvement of neurological symptoms immediately after surgery. However, her neurological symptoms began to gradually deteriorate. She exhibited a dropped head and complained of difficulty maintaining horizontal gaze. Postoperative images showed a focal cervical kyphotic deformity causing anterior shift of the head, and recurrence of spinal cord compression was observed. She underwent additional surgeries for three times, but none of them restored her to baseline status. Retrospectively, the preoperative loading axis of the head existed anteriorly, and she also had a high T1 slope because of rigid thoracic kyphosis. Her preoperative hyper cervical lordosis was compensation for the global spinal malalignment. After LAMP, in accordance with decreases in her cervical lordosis, her head shifted anteriorly. The abnormal lever arm acting on the neck put further stress on the neck extensors, and the overstretched neck extensors possibly no longer generated enough power to raise the head. Uncompensated very high T1 slope because of marked thoracic kyphosis plus invasion of the posterior extensor mechanism by LAMP may have contributed to her catastrophic DHS development.

Conclusions

In the treatment of cervical myelopathy, posterior decompression alone should be applied carefully to elderly patients with cervical sagittal imbalance even if they have apparent cervical lordosis. Once DHS occurs because of cervical sagittal imbalance, normalization of global spinal balance through corrective osteotomy may be indispensable for a successful outcome.