Single-door cervical laminoplasty using titanium miniplates alone

Impact of the K-line in patients with ossification of the posterior longitudinal ligament: Analysis of sagittal cervical curvature changes and surgical outcomes

Objective

This study aimed to investigate the relationship of the K-line with sagittal cervical curvature changes and surgical outcomes in patients with cervical ossification of the posterior longitudinal ligament (OPLL).

Methods

We retrospectively reviewed 84 patients with OPLL who underwent posterior cervical single-door laminoplasty. The patients were divided into a K-line-positive (+) group and a K-line-negative (-) group. Perioperative data, radiographic parameters, and clinical outcomes were compared between the two groups.

Results

Of 84 total patients, 50 patients were in the K (+) group and 29 patients were in the K (-) group. Neurological function improved in both groups after laminoplasty. The C2-7 Cobb angle, T1 slope, and C2-7 sagittal vertical axis were significantly changed in the K(-) group compared with those in the K (+) group before the operation and at the 3-month and final follow-ups.

Conclusion

Neurological function was recovered in both groups, and the clinical effect on the K (+) group was better than that on the K (-) group. The cervical curvature in patients with OPLL tends to be anteverted and kyphotic after laminoplasty and is an important factor in reducing the clinical effect.

Relationship between spinocranial angle and clinical outcomes after laminoplasty in patients with ossification of the posterior longitudinal ligament

Background

The aims of this study were to identify the relationship between the spinocranial angle (SCA) and clinical outcomes and to explore whether the SCA is a suitable indicator to predict clinical outcomes for patients with ossification of the posterior longitudinal ligament (OPLL).

Methods

Sixty-five patients with cervical OPLL who underwent laminoplasty with at least 24 months of follow-up were selected for the current study and were divided into two groups according to whether the SCA was greater than or less than the mean preoperative SCA. Sagittal alignment changes were compared between the groups. The Pearson correlation coefficient was applied to assess the relationship among sagittal parameters. Univariate and multiple linear regression analyses were applied to identify the relationship between the recovery rate (RR) and radiological parameters.

Results

Patients were classified into two groups based on the mean value of preoperative SCA (85.1°). SCA was negatively correlated with T1 slope (T1s) and cervical lordosis (CL) and positively correlated with the C2–7 sagittal vertical axis (cSVA) (p < 0.001). Patients with lower SCA had larger T1s and CL preoperatively and at the follow-up (T1s: p < 0.001; CL: p < 0.001) and showed greater loss of cervical lordosis after laminoplasty (p < 0.001). However, no significant differences in the incidence of kyphosis, Japanese Orthopaedic Association (JOA) or RR were noted between the two groups. Although Pre-SCA, Pre-CL, F/U-CL and Pre-T1sCL were significantly associated with RR, these indicators were not associated with RR in the multivariate regression analysis.

Conclusion

Patients with lower SCA tended to have higher T1s and CL before surgery and greater loss of cervical lordosis at the follow-up visit but still maintained a greater lordosis angle. Although preoperative SCA is significantly related to RR, the relationship is not sufficient to indicate that preoperative SCA can be used to predict clinical outcomes. Therefore, further research is needed to confirm the impact of SCA on clinical outcomes for OPLL.

The opening size of the laminoplasty is dependent on the groove size: A numerical study

BACKGROUND

The expansion of the cervical vertebrae lamina appears to be crucial to related surgical procedures. The dimensions of the groove influence the strain concentration within the lamina of the vertebra and, thus, the potential success or failure of respective surgical procedure. The aim of this computational study is to clarify both the role of the size of the groove with concern to both the open door and the double door laminoplasty techniques.

METHODS

Finite element models were created via computer tomography with varying lamina groove dimensions. Displacements were applied to the models at the open side of the vertebral arch and the vertebral body was constrained prior to movement along all the axes. The maximal opening size measured on the inner side of the lamina and the percentage increase in the initial spinal areas were subsequently analyzed.

FINDINGS

The elastic strain concentration value was observed for the groove in all cases, while the maximal principal elastic strain concentration value was observed at the opposite side to the groove cut into the lamina, also in all cases. The maximal area increase related to the 4 mm groove accompanied by the preservation of the ventral cortex of the bone.

INTERPRETATION

The study suggested three conclusions a) the wider the groove, the greater is the opening potential, b) the maximal opening size following laminoplasty is not dependent on the depth of the bone cut for this type of groove, c) no benefit accrues in terms of the opening size following the cutting of a supplementary groove at the beginning of the lamina.

Treatment of spinal cord compression caused by C2 osteochondroma with reconstruction and fusion after total resection: Case report and literature review

Context: Osteochondroma is the most common benign tumor of the bone, but spinal osteochondroma is rare. We report a case of cervical osteochondroma in multiple exostoses arising from the lamina of the C2 vertebra, presenting with features of compressive myelopathy in a 22-year-old male. Total resection of the tumor and atlantoaxial fixation and fusion after reconstruction of the C1 posterior arch were performed.Findings: The patient recovered significantly. He was asymptomatic and no sign of recurrence was observed after one-year follow-up.Conclusions: Osteochondroma should be considered as a rare cause of spinal cord compression. Entire removal of the tumor will result in complete decompression and can reduce the risk of recurrence. We provide a new approach to reconstruct after resection.

Effect of K-line on posterior cervical surgery in patients with posterior longitudinal ligament ossification

PURPOSE

To evaluate the effect of K-line on posterior single-door decompression with fusion fixation (PFF) and posterior single-door decompression with non-fusion fixation (PNF) for patients with ossification of posterior longitudinal ligament (OPLL).

METHODS

A total of 65 patients with OPLL were analyzed retrospectively. They consisted of 44 patients with positive K-line, designated as the K ( +) group, and 21 patients with negative K-line, designated as K (-). The patients were also divided into a PFF group (38 patients) and a PNF group (27 patients). The Japanese Orthopaedic Association (JOA) score, C2-C7 Cobb angle, improvement rate of JOA score, and complications were calculated and statistically analyzed between the groups.

RESULTS

In the K ( +) group, there were no significant differences in the incidence of C5 nerve root palsy and C2-C7 Cobb angle between the two groups of surgical patients, but there were significant differences in the improvement rate of JOA score and the incidence of axial pain. In the K (-) group, there were no significant differences in the incidence of axial pain, the incidence of C5 nerve root palsy, and preoperative C2-C7 Cobb angle between the two groups, but significant differences were observed in the improvement rate of JOA score and C2-C7 Cobb angle at the last follow-up.

CONCLUSION

In the K ( +) group, the improvement rate of JOA score was higher and the incidence of axial pain was lesser in the PNF group than in the PFF group. In the K (-) group, the improvement rate of JOA score was higher in the PFF group than in the PNF group, and there was significant loss of C2-C7 Cobb angle in the PNF group.

Postoperative Rigid Cervical Collar Leads to Less Axial Neck Pain in the Early Stage After Open-Door Laminoplasty-A Single-Blinded Randomized Controlled Trial

BACKGROUND

Cervical collars are used after laminoplasty to protect the hinge opening, reduce risks of hinge fractures, and avoid spring-back phenomena. However, their use may lead to reduced range of motion and worse neck pain.

OBJECTIVE

To investigate the clinical, radiological, and functional outcomes of patients undergoing single-door laminoplasty with or without collar immobilization.

METHODS

This was a prospective, parallel, single-blinded randomized controlled trial. Patients underwent standardized single-door laminoplasty with mini-plates for cervical myelopathy and were randomly allocated into 2 groups based on the use of collar postoperatively. Clinical assessments included cervical range of motion, axial neck pain (VAS [visual analogue scale]), and objective scores (short-form 36-item, neck disability index, and modified Japanese Orthopaedic Association). All assessments were performed preoperatively and at postoperative 1, 2, 3, and 6 wk, and 3, 6, and 12 mo. Comparative analysis was performed via analysis of variance adjusted by baseline scores, sex, and age as covariates.

RESULTS

A total of 35 patients were recruited and randomized to collar use (n = 16) and without (n = 19). There were no dropouts or complications. There were no differences between groups at baseline. Subjects had comparable objective scores and range of motion at postoperative time-points. Patients without collar use had higher VAS at postoperative 1 wk (5.4 vs 3.5; P = .038) and 2 wk (3.5 vs 1.5; P = .028) but subsequently follow-up revealed no differences between the 2 groups.

CONCLUSION

The use of a rigid collar after laminoplasty leads to less axial neck pain in the first 2 wk after surgery. However, there is no additional benefit with regards to range of motion, quality of life, and complication risk.

Clinical outcome and radiological findings after cervical open door laminoplasty with titanium basket

OBJECT

Cervical laminoplasty, which is well described in the Japanese literature, is the gold standard for decompressing multilevel spinal cord compression. Several spacers have been introduced to provide enough decompression of the spinal canal and reconstruct the stable posterior elements. The purpose of this study was to retrospectively evaluate radiological outcomes after open door laminoplasty using the titanium spacer (Laminoplasty Basket: L-Basket; Ammtec, Tokyo).

METHODS

Between July 2014 and June 2016, 31 patients with cervical spondylotic disease, including OPLL, were underwent open door laminoplasty with this device. All patients were clinically assessed by JOA score. The average follow-up period was 48.9 months with a range of 37-60 months. Postoperative radiological evaluation revealed bone union on both the open side and the gutter side from 12 months to 36 months after surgery on computed tomography.

RESULTS

The clinical outcome improved from 10.9 points on the Japanese Orthopaedic Association scale to 15.8 points at 3 months after surgery and there were no significant major complications such as the implant failure. The bone union rate of the gutter side was 85.9% (85/99) at 1 year, 96.0% (95/99) at 3 years after surgery and of the open side was 57.6% (57/99) at 1 year, 89.9% (89/99) at 3 years after surgery. Circumferential fusion was confirmed 85.9% (85/99) of the time.

CONCLUSION

This titanium spacer seemed to have the potential of promoting bone union between the spacer and both lamina, and lateral mass in cervical laminoplasty which is a safe procedure with satisfactory clinical results.

Comparing clinical outcomes of using 3 versus 5 titanium miniplates in laminoplasty for multilevel cervical myelopathy: A prospective cohort study

STUDY DESIGN

Prospective cohort study.

OBJECTIVE

The aim of this study was to compare clinical outcomes, radiographic changes, and complications of cervical expansive open-door laminoplasty（EOLP）for cervical multilevel myelopathy, using either 3 or 5 titanium miniplates.

SUMMARY OF BACKGROUND DATA

Cervical EOLP is a common and effective operation for cervical myelopathy. Standard procedures utilise either 3 or 5 titanium miniplates; however, no definite conclusion has been given yet on the relationship between clinical outcomes and the quantity of titanium miniplates.

METHOD

We performed a prospective study of 92 patients who underwent EOLP with either 3 (n ​= ​34) or 5 (n ​= ​58) titanium miniplates at our institution from March 2012 to June 2016. Clinical and radiologic outcomes and complications were compared.

RESULT

Compared with the 5 titanium miniplates group, the 3 titanium miniplates group had shorter operation times and less blood loss (P ​< ​0.05) and needed fewer costs (P ​< ​0.01) during index hospitalisation. The preoperative cervical curvature angle decreased in both groups and revealed no significant differences. There was no significant difference between the two groups in the Japanese Orthopedic Association (JOA) score, JOA recovery rate, loss of range of motion (ROM), anteroposterior diameter (APD), or spinal canal complications (P ​> ​0.05).

CONCLUSION

Cervical EOLP using 3 titanium miniplates is associated with shorter operation times, less blood loss, and lower operation costs compared with using 5 titanium miniplates.

THE TRANSLATIONAL POTENTIAL OF THIS ARTICLE

Expansive open-door laminoplasty (EOLP) is an effective procedure for treating multilevel cervical spondylotic myelopathy. The present study indicated that 3 titanium miniplates could achieve similar clinical outcomes but with shorter operation times, less blood loss and operation costs compared with 5 titanium miniplates. These findings may provide some references for clinical applications.

Comparison of clinical outcomes of expansive open-door laminoplasty with unilateral or bilateral fixation and fusion for treating cervical spondylotic myelopathy: a multi-center prospective study

Background

The present study evaluated the clinical outcomes and safety of expansive open-door laminoplasty, when securing with C4 – C6 lateral mass screw and fusion.

Methods

A total of 110 patients with cervical spondylotic myelopathy (CSM) were enrolled. There were 88 male and 22 female, with mean age at 60.55 ± 10.95 years. All of the patients underwent expansive open-door laminoplasty with unilateral or bilateral C4–6 lateral mass screws fixation and fusion. Clinical data, including age, gender, operation-related information, pre- and post-operation Japanese Orthopedic Association (JOA) scores, and cervical curvatures were collected.

Results

The mean follow-up time of the cohort was 13.61 ± 9.53 months. Among the 110 patients, 33 of them were allocated to Unilateral group, and 77 of them were in Bilateral group. The mean JOA score of the 110 patients before surgery was 10.07 ± 2.39, and the score was improved significantly to 12.85 ± 2.45 after surgery. There were no reported cases of neurological deterioration or symptom worsening. Patients in both the Unilateral group and Bilateral groups had significant improvement of JOA scores. Among all patients, the most frequently observed complications were axial symptoms (n = 7). The average preoperative cervical curvature among all patients was 15.17 ± 5.26, and the post-surgery curvature was 14.41 ± 4.29. Similar observations were found between Unilateral and Bilateral groups.

Conclusion

The modified surgical approach provided satisfactory clinical outcome in patients with CSM. The unilateral and bilateral fixation appeared to provide similar outcomes, in terms of cervical curvature maintenance and improvement of clinical symptoms. However, the examination of the exact differences between the two fixation methods await further biomechanical studies.

Development and Achievement of Cervical Laminoplasty and Related Studies on Cervical Myelopathy

Cervical laminoplasty (CL) is one of the surgical methods via the posterior approach for treating patients with multilevel affected cervical myelopathy (CM). The main purpose of CL is to decompress the cervical spinal cord by widening the narrowed spinal canal, combined with preserving the posterior anatomical structures to the degree possible and preserving the widened space stably. During the development and improvement of spine surgeries including CL, various studies on CM have progressed and useful achievements have been obtained: (1) posterior cervical spine fixation systems that can be used in combination with CL simultaneously have been developed; (2) various materials to stably maintain the enlarged spinal canal have been developed; (3) the main influential factors on the surgical results are the inner factors of the patients, such as the patient's age and the disease duration; (4) various surgical methods to preserve the function of the posterior cervical muscles have been tried to avoid postoperative kyphotic changes of the cervical spine; (5) postoperative complications, such as C5 palsy and axial pain, have been examined, and the countermeasures have been tried; (6) K-line on lateral X-ray films has been applied to evaluate the indication of CL in patients with CM due to ossification of the posterior longitudinal ligament (OPLL) preoperatively; and (7) the method and idea of CL have been adapted to surgeries at the thoracic and lumbar spine. However, some issues remain to be resolved, such as the deterioration of neurological findings, especially in patients with continuous or mixed-type OPLL, the postoperative kyphotic-directional alignment change of the cervical spine, C5 palsy, and axial pain.

In vitro biomechanical evaluation of a monocoque plate-spacer construct for cervical open-door laminoplasty

PURPOSE

To evaluate biomechanical differences between two surgical procedures for cervical open-door laminoplasty using human cadaveric spines.

METHODS

Twenty-four cervical vertebrae (C4-C6) from eight fresh-frozen human cervical spines were subjected to mechanical testing after being instrumented for open-door laminoplasty using a newly designed plate-spacer device with a monocoque structure (plate-spacer group; n = 12) or by conventional miniplate-alone fixation (miniplate group; n = 12). Cantilever bending testing was performed by applying a compressive load in the cranio-caudal direction to the base of the spinous process of the reconstructed laminar arch constructs until failure and strength and stiffness of the laminar arch were determined. The results are presented as mean ± standard deviation.

RESULTS

The plate-spacer group was approximately twice as strong as the miniplate group (27.6 ± 16.5 N vs. 13.5 ± 7.3 N, p < 0.05). Stiffness in the plate-spacer group exhibited the same trend (19.6 ± 9.3 N/mm vs. miniplate group: 11.4 ± 6.9 N/mm, p < 0.05).

CONCLUSION

The fixation with the monocoque plate-spacer construct for open-door laminoplasty provided higher structural properties when compared against the plate-alone fixation. The spacer in the plate-spacer construct appears to contribute by preventing large deformations of the laminar arch caused by bending in cranio-caudal direction. Future studies will be required to investigate stress/strain distribution in the laminar arch constructs.

Comparable clinical and radiological outcomes between skipped-level and all-level plating for open-door laminoplasty

PURPOSE

To compare the clinical and radiological outcomes between skipped-level and all-level plating for cervical laminoplasty.

METHODS

Patients with cervical spondylotic myelopathy (CSM) treated by open-door laminoplasty with minimum 2-year postoperative follow-up were included. All patients had opening from C3-6 or C3-7 and were divided into skipped-level or all-level plating groups. Japanese Orthopaedic Association (JOA) scores and canal measurements were obtained preoperatively, immediate (within 1 week) postoperatively, and at 2, 6 weeks, 3, 6 and 12 months postoperatively. Paired t test was used for comparative analysis. Receiver operating characteristic analysis was used to determine the canal expansion cutoff for spring-back closure.

RESULTS

A total of 74 subjects were included with mean age of 66.1 ± 11.3 years at surgery. Of these, 32 underwent skipped-level plating and 42 underwent all-level plating. No significant differences were noted between the two groups at baseline and follow-up. Spring-back closure was observed in up to 50% of the non-plated levels within 3 months postoperatively. The cutoff for developing spring-back closure was 7 mm canal expansion for C3-6. No differences were observed in JOA scores and recovery rates between the two groups. None of the patients with spring-back required reoperation.

CONCLUSIONS

There were no significant differences between skipped-level and all-level plating in terms of JOA or recovery rate, and canal diameter differences. This has tremendous impact on saving costs in CSM management as up to two plates per patient undergoing a standard C3-6 laminoplasty may be omitted instead of four plates to every level to achieve similar clinical and radiological outcomes.

LEVEL OF EVIDENCE

III. These slides can be retrieved under Electronic Supplementary Material.

Recent Surgical Methods of Double-door Laminoplasty of the Cervical Spine (Kurokawa's Method)

Introduction

Double-door laminoplasty (DDL) of the cervical spine (Kurokawa's method) was developed as one of posterior decompression surgical methods in the late 1970s and after then has been modified by adding various procedures such as the posterior muscle handling and the use of artificial spacers.

There are three principles of DDL: First, to decompress the cervical spinal cord by central splitting of the spinous processes and laminae, preserving those lengths as much as possible and widening the spinal canal space symmetrically. Second, to maintain the widened spinal canal space steadily by fixing spacers made of hydroxyapatite the contour is almost the same as the widened space. Third, to re-suture the semispinalis muscles to the C2 spinous process to restore the strength of the posterior cervical muscles.

Technical note

The important technical points in performing osteotomy are as follows: At each vertebra, osteotomy is performed from the caudal side and gradually proceeds to the cranial side because there is a space between the lamina and the dura mater at the caudal side and the osteotomy can be safely made. The surgeon must pay attention to the changes in color of the osteotomy site from red of cancellous bone, to white of the inner cortex, and finally to yellow of the yellow ligament and extradural fat tissue. Attention must be paid to the changes in sound and tactile sensation delivered from the air-drill when completing osteotomy of the inner cortex of lamina. By moving an air-drill slowly, tactile sensation can be more sensitive. During osteotomy, the process must be checked frequently by touching the inner cortex of the lamina with a probe.

Conclusion

At present, DDL is a useful surgical method for cervical myelopathy at multiple level lesions.

Initial radiological findings utilizing titanium basket for cervical open door laminoplasty

BACKGROUND

Cervical laminoplasty, utilizing different spacers to ''keep the door open,'' is the gold standard in Japan for treating ossification of the posterior longitudinal ligament (OPLL) and cervical spondylotic myelopathy (CSM). Here, we utilized a novel titanium ''basket'' spacer (Laminoplasty Basket: L-Basket; Ammtec, Tokyo) to perform open door cervical laminoplasty to keep the "door open" while also allowing for bony fusion across the open door.

METHODS

Twenty-seven patients with/without OPLL were treated with open door laminoplasty utilizing the basket spacer. Patients were analyzed with preoperative/postoperative JOA scores, and X-rays/computed tomography (CT) at least 12 months (range, 12-19 months) postoperatively.

RESULTS

Improvement from the preoperative JOA score of 10.3 points to the postoperative JOA of 14.8 points was noted 3 months postoperatively. There were no complications except one patient who had transient C5 palsy. Twelve months postoperatively, X-rays/CT documented fusion on both the open (62%) and hinge sides (90.2%); circumferential fusion was observed 59.8% of the time.

CONCLUSION

This titanium "basket" spacer (Laminoplasty Basket: L-Basket; Ammtec, Tokyo) promoted bone union between the spacer and both lamina, lateral masses following cervical laminoplasty without undue complications.

Preoperative Factors Affecting Postoperative Axial Symptoms After Single-Door Cervical Laminoplasty for Cervical Spondylotic Myelopathy: A Prospective Comparative Study

Background

Postoperative axial symptoms (post-AS) after single-door cervical laminoplasty for cervical spondylotic myelopathy (CSM) are a common and severe complication that adversely affects normal daily activities. Their etiology remains unclear. It is important to know which preoperative factors are the most predictive of post-AS. Therefore, this study aimed to elucidate the preoperative factors affecting post-AS.

Material/Methods

A total of 102 patients with CSM who underwent single-door cervical laminoplasty between 2009 and 2015 were studied. According to operation date, patients were prospectively assigned to treatment with conventional laminoplasty (CL) or modified laminoplasty (ML). Preoperative clinical and radiological parameters were recorded. The incidence of post-AS with 2 procedures was compared prospectively. Multivariate analysis was used to determine the preoperative factors affecting post-AS.

Results

The incidence of post-AS after ML was significantly lower than after CL (P=0.010). ML and preoperative cervical C2–7 Cobb angle (CCA) were significant protective factors against post-AS (ML: P=0.011, odds ratio=0.302; CCA: P=0.042, odds ratio=0.947). Patients with post-AS had a lower preoperative CCA than patients without post-AS (P=0.043). The other preoperative factors were not significantly associated with post-AS.

Conclusions

The results of this study suggest that choosing ML procedure or selecting patients with high preoperative CCA can reduce the incidence of post-AS after single-door cervical laminoplasty for CSM, and that the other preoperative clinical or radiological parameters are less critical.