Cervical alignment, range of motion, and instability after cervical laminoplasty

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.

The preservation of cervical flexibility helps maintain cervical sagittal alignment after laminoplasty

BACKGROUND CONTEXT

Cervical spine range of motion (ROM) is a critical factor in changes in cervical sagittal alignment (CSA) and clinical outcomes after cervical laminoplasty (LMP). However, the impact of postoperative cervical ROM on CSA after cervical LMP is still unclear.

PURPOSE

Evaluating the imaging and symptomatic data from patients with cervical spondylotic myelopathy (CSM) to identify the influence of postoperative cervical ROM on post-LMP CSA and surgical outcomes.

STUDY DESIGN

Retrospective study.

PATIENT SAMPLE

Eighty-six patients undergoing LMP due to multilevel CSM OUTCOME MEASURES: Radiographic parameters were measured before surgery and at follow-up: cervical lordosis (CL), T1 slope (T1S), cervical sagittal vertical axis (cSVA), CL in flexion (Flex CL), CL in extension (Ext CL), total cervical spine range of motion (ROM), cervical spine range of flexion (Flex ROM), and cervical spine range of extension (Ext ROM). Japanese Orthopedic Association (JOA) and visual analog score (VAS) were used to assessed clinical outcomes. Other parameters included age, gender, body mass index (BMI), follow-up time, number of surgical segments, proximal level, distalis level, and collar wear time.

METHODS

We divided patients according to the changes in CSA (loss of cervical lordosis (LCL)>10°, or ≤10°; an increase in cervical sagittal vertical axis (I-cSVA) >10mm, or ≤10mm). A receiver-operating characteristic curve (ROC) analysis was constructed to identify the optimal cut-off value to discriminate the patients with and without postoperative deterioration of CSA.

RESULTS

The postoperative total and Flex ROM were significantly lower in the LCL>10° and I-cSVA>10mm groups. Multivariate logistic regression analysis showed that low post-Flex ROM was significant risk factor for postoperative deterioration of CSA. ROC showed that the cut-off value for postoperative Flex ROM was 15.60°. Improvements in JOA recovery rate and neck pain were more significant in the flexibility group (post-Flex ROM ≥15.6°) after surgery. Patients in the stiffness group (post-Flex ROM <15.6°) wore a collar longer.

CONCLUSIONS

The preservation of cervical flexibility can maintain CSA after cervical LMP. Postoperative cervical stiffness is related to poor surgical outcomes because significant cervical kyphotic change and sagittal imbalance are likely to occur after surgery. Prolonged wearing of cervical collar is correlated with cervical stiffness following cervical LMP.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

What is the Preferable Method for the C3 and C7 Segments in Unilateral Open-Door Laminoplasty for Patients Diagnosed with Cervical Spondylotic Myelopathy?

BACKGROUND

Traditional C3-C7 unilateral open-door laminoplasty (UOLP) often leads to various postoperative complications as a result of damage of cervical posterior muscles and nuchal ligaments. We aimed to thoroughly evaluate postoperative outcomes after our modified UOLP versus traditional UOLP in treating multilevel cervical spondylotic myelopathy (MCSM).

METHODS

Seventy-six patients with MCSM who underwent the modified UOLP with C3 laminectomy and C7 upper hemilaminectomy (40 patients) or traditional C3-C7 UOLP (36 patients) were included. Preoperative and postoperative cervical radiologic parameters, as well as clinical and surgical outcomes, were evaluated.

RESULTS

Postoperatively, Japanese Orthopaedic Association scores improved significantly more in the modified UOLP group than in the traditional UOLP group (P = 0.028), whereas visual analog scale scores and Neck Disability Index improved similarly in both groups. Follow-up scores for Japanese Orthopaedic Association, Neck Disability Index, and visual analog scale were not significantly different between the 2 groups. At the final follow-up, the C2-C7 sagittal vertical axis and T1 slope increased in the traditional UOLP group and did not change in the modified UOLP group and were unchanged in the modified UOLP group. The C2-C7 Cobb angle decreased significantly in the traditional UOLP group and did not change in the modified UOLP group. The modified UOLP group lost less cervical posterior muscle area compared with the traditional UOLP group (3.72% ± 3.54% vs. 6.67% ± 2.81%; P < 0.001). The range of motion in the modified UOLP group was significantly greater than in the traditional UOLP group at the final follow-up (P < 0.001). Also, the modified UOLP group experienced a notable reduction in operative time, blood loss volume, and postoperative hospital stay.

CONCLUSIONS

We recommend performing our modified UOLP with C3 laminectomy and C7 upper hemilaminectomy instead of traditional C3-C7 UOLP.

Is laminectomy necessary for C1-C2 epidural schwannomas?

PURPOSE

Spinal schwannomas often require laminectomy for gross total resection. However, laminectomy may not be necessary due to the unique anatomy of epidural schwannomas at the C1-2 level, even with the intradural part. This study aimed to determine the need for laminectomy by comparing factors between patients who underwent laminectomy and those who did not and to identify the benefits of not performing laminectomy.

METHODS

Fifty patients with spinal epidural schwannoma confined to C1-C2 level were retrospectively collected and divided into groups based on whether laminectomy was intended and performed. In all cases where laminectomy was conducted, patients underwent laminoplasty using microplate-and-screws, which deviates from the conventional laminectomy approach. Tumor characteristics were compared, and a cut-off value for laminectomy was determined. Outcomes were compared between groups, and factors influencing laminectomy were identified. Postoperative changes in cervical curves were measured.

RESULTS

The diameter of the intradural part of the tumor was significantly longer in the laminectomy performed group, with a 14.86 mm cut-off diameter requiring laminectomy. Recurrence rates did not differ significantly between groups. Surgery time was substantially longer for the laminectomy performed group. No significant changes were observed in Cobb's angles of Oc-C2, C1-C2, and Oc-C1 before and after surgery.

CONCLUSION

The study showed that the diameter of the intradural part of the tumor influenced the decision to perform laminectomy for removing epidural schwannomas at C1-C2. The cut-off value of the diameter of the intradural part of the tumor for the laminectomy was 14.86 mm. Not performing laminectomy can be a viable option with no significant differences in removal and complication rates.

Clinical outcomes of modified versus traditional expansive open-door laminoplasty for cervical spondylotic myelopathy: A single-institution experience

PURPOSE

To compare the surgical outcomes of modified expansive open-door laminoplasty (EOL) (C4-C6) and traditional EOL (C3-C7) in patients with cervical spondylotic myelopathy (CSM).

METHODS

One hundred and two CSM patients were retrospectively recruited from Fujian Medical University Union Hospital between March 2012 and December 2019. Seventy-one patients with CSM underwent modified EOL, and 31 patients underwent traditional EOL. The primary endpoint was axial symptoms.

RESULTS

Patients who underwent modified EOL had a significantly lower incidence of axial symptoms (odds ratio: 0.273; 95% confidence interval: 0.184-0.691; p = .002). The length of hospital stay (p = .263), and intraoperative blood loss (p = .402) were not significantly different between the groups. Significantly more postoperative drainage was observed in patients who underwent modified EOL (p < .001), while the cost of hospitalization in patients treated with traditional EOL was higher (p = .011). There were significant differences between modified and traditional EOL for the changes in range of motion (p < .001), modified Japanese Orthopaedic Association score (p = .001), and the Nurick grade (p = .014), while the changes of visual analogue scale (p = .250), and the neck disability index (p = .134) were not significantly different between the groups.

CONCLUSION

This study found modified EOL may decrease the incidence of axial symptoms in patients with CSM compared to traditional EOL.

Effect of T1 Slope on Disappearance of Cervical Lordosis after Posterior Cervical Double-Door Laminoplasty Based on Medical Informatics

Cervical sagittal balance plays a pivotal role in spine surgeries as it has a significant impact on the clinical outcomes in cervical spine surgery. Image processing techniques have significantly improved the accuracy and precision of cervical surgical techniques. This study aims to investigate the effects of T1 slope (T1s) on the disappearance of cervical lordosis after posterior cervical double-door laminoplasty using medical informatics and radiographic measures. To do so, we determined and measured the loss of T1s and cervical lordosis during the postoperative follow-up period in patients with double-door posterior cervical laminoplasty. Patients (n = 40) who underwent posterior cervical double-door laminoplasty participated in this study. For all patients, the difference between the preoperative T1s (angle between the upper edge of T1 and the horizontal line) and preoperative and postoperative cervical lordosis (Cobb method) was estimated, and the linear relationship between the two was statistically analyzed to observe the influence of preoperative T1s on postoperative cervical lordosis disappearance. The average preoperative T1s was 23.54°, and the average preoperative cervical lordosis angle was 8.50°. After 1-20 months of follow-up (mean = 9.53 months), the average postoperative cervical lordosis was 8.50°, and the average loss of cervical lordosis was 0.22°. Twenty cases had different degrees of lordosis angle loss after the operation, with an average loss of 9.31°. All patients were divided into groups A and B, according to a mean value of T1s = 23.54°, of which T1S > 23.54° was group A and T1s < 23.54 was group B. Cervical lordosis was quantified by the C2-C7 Cobb angle. The Cobb angle difference of cervical lordosis was measured before and after the operation, and its correlation with preoperative T1s was assessed. The preoperative Cobb angle and cervical curvature changes in the two groups were statistically compared, and the difference between the two groups was statistically significant (p < 0.05). The group with a T1s > 23.54° had greater loss of preoperative Cobb angle and cervical curvature. In group A, the mean preoperative cervical disability index (NDI) was 32.4 ± 3.4, and the mean postoperative NDI score was 16.5 ± 2.1. The mean preoperative VAS scores of neck pain and neck pain were 5.41 ± 1.1 and 5.55 ± 0.3, respectively, and the improvement in neck pain was -0.2%. The mean preoperative NDI in group B was 30.1 ± 2.9, and the mean postoperative NDI score was 11.5 ± 3.1. The mean VAS score for preoperative neck pain was 5.11 ± 1.2, that for postoperative neck pain was 4.18 ± 0.7, and that for neck pain improved by 18%. There was a significant difference between the two groups (p < 0.05). The disappearance of cervical lordosis after posterior cervical double-door laminoplasty is an important cause of postoperative cervical spine pain. The T1s is meaningful for predicting the loss of postoperative curvature in patients undergoing posterior cervical double-door laminoplasty. This is especially true for patients with good preoperative cervical curvature without ankylosis and kyphosis but with a wide T1s.

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

BACKGROUND CONTEXT

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

PURPOSE

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

STUDY DESIGN

A retrospective study.

PATIENT SAMPLE

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

OUTCOME MEASURES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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.

Kinematics after cervical laminoplasty: risk factors for cervical kyphotic deformity after laminoplasty

BACKGROUND CONTEXT

Laminoplasty of the cervical spine is widely used as an effective surgical method to treat compressive myelopathy of the cervical spine; however, there is an adverse effect of kyphosis after surgery. The risk factors or predictors of kyphosis have not been sufficiently evaluated.

PURPOSE

To assess the risk factors for kyphosis following laminoplasty.

STUDY DESIGN

Retrospective study.

PATIENT SAMPLE

Patients diagnosed with cervical spondylotic myelopathy (CSM) or ossification of the posterior longitudinal ligament (OPLL) who underwent laminoplasty between May 2011 and October 2018 were enrolled.

OUTCOME MEASURES

Changes in lordosis and range of motion (ROM).

METHODS

Radiological imaging data were collected from simple neutral and flexion-extension radiographs at baseline and at 2-year follow-up. The ROM from the neutral position to complete flexion was defined as the flexion capacity, and the ROM from the neutral position to complete extension was defined as the extension capacity.

RESULTS

This study included 53 patients (mean age, 59.3 years). Multivariate linear regression analysis revealed that, the smaller the preoperative extension capacity, the greater was the decrease in lordosis (p=.025), while the larger the T1 slope, the greater was the decrease in lordosis following laminoplasty (p= .008). Correlation analysis revealed that C2-7 lordosis increased with increasing baseline T1 slope before surgery (p< .01). In patients with large preoperative C2-7 lordosis, the postoperative decrease in ROM tended to be greater (p= .028). However, the degree of lordosis and ROM reduction did not demonstrate a clear correlation with the clinical outcomes at 2 years after surgery.

CONCLUSIONS

Kyphotic changes in the cervical spine following laminoplasty were related to preoperative radiological parameters. The greater the preoperative extension capacity, the lower was the decrease in lordosis, and the greater the T1 slope, the greater was the decrease in lordosis.

Changes in cervical sagittal alignment and the effects on cervical parameters in patients with cervical spondylotic myelopathy after laminoplasty

Objective:

To monitor changes in cervical parameters before and after laminoplasty surgery. Cervical parameters and health-related quality-of-life (HRQOL) values that may be affected after laminoplasty were examined before and after surgery. The clinical and radiological course of these values was monitored, and their interaction with all spinal radiological parameters was revealed.

Materials and Methods:

Nineteen patients who underwent clinical and radiological evaluation for 2 years were followed in this study. Neck disability index, visual analog scale, and short form 36 scores were determined to evaluate HRQOL. For radiological parameters, the C0-C2 angle, C2-C7 angle, cervical sagittal vertical axis, T1 slope angle, neck tilt (NT) and thoracic inlet angle were used. The results of the 4-month, 1 year and 2-year follow-ups were statistically evaluated.

Results:

Both the HRQOL and cervical radiological parameters deteriorated in the first 4 months and returned to normal in the 2^nd year. Statistically, all parameters were meaningful (P < 0.05), except for NT.

Conclusion:

Cervical parameters and HRQOL values, which deteriorated in the early period, recovered in the late period in the long-term follow-up of patients undergoing laminoplasty. The important point is that preoperative cervical parameters suitable for laminoplasty should be present, and spinopelvic parameters should be normal.

Preoperative Parameters for Predicting the Loss of Lordosis After Cervical Laminoplasty

STUDY DESIGN

Retrospective study.

OBJECTIVE

The preoperative parameters for predicting the loss of lordosis after cervical laminoplasty were investigated in the present study.

SUMMARY OF BACKGROUND DATA

Cervical laminoplasty is an effective surgical method to decompress the cervical spinal cord. Maintaining cervical lordosis after laminoplasty is an important factor to ensure the successful surgical treatment. To know the preoperative parameters for predicting loss of lordosis after cervical laminoplasty is important for better outcome after laminoplasty.

METHODS

In this retrospective study, 106 patients who underwent cervical laminoplasty from 2011 to 2015 were reviewed. The preoperative parameters; T1 slope (TS), Cobb lordotic angle (CLA) and sagittal vertical axis (SVA) at C2-C7, relative cross-sectional area (RCSA), and fatty degeneration of deep extensor muscles (DEMs) were measured. Visual analogue scale (VAS) and modified Japanese Orthopedic Association (mJOA) scores were used for clinical assessment. Correlation analysis was performed between the postoperative CLA change and preoperative parameters. The patients were divided into the decreased- or maintained-lordosis groups based on the difference between postoperative and preoperative CLA. All preoperative parameters were compared between groups.

RESULTS

Based on correlation analysis, preoperative TS (P = 0.001), TS-CLA (P = 0.046), RCSA at C7-T1 (P < 0.001), and fatty degeneration of DEMs (P < 0.001) were correlated with loss of lordosis. Among the 106 patients, 68 showed decreased-lordosis and 38 maintained-lordosis. Preoperative TS (P = 0.003), SVA (P = 0.014), TS-CLA (P = 0.015), and RCSA at C7-T1 (P = 0.005) were significantly different between groups. In both correlation and comparative analyses, higher TS and TS-CLA and less RCSA at C7-T1 were associated with loss of lordosis. Neck pain VAS (P < 0.001) and mJOA scores (P < 0.001) were significantly improved in the maintained-lordosis group.

CONCLUSION

Maintaining cervical lordosis is important for clinical outcomes after laminoplasty. Preoperative higher TS, TS-CLA, and less RCSA at C7-T1 were considered as predictors for loss of lordosis. These characteristics should be considered when choosing the surgical method to help maintain cervical lordosis.

LEVEL OF EVIDENCE

3.

Effect of posterior cervical expansive open-door laminoplasty on cervical sagittal balance

PURPOSE

Posterior cervical expansive open-door laminoplasty (LAMP) is a mature surgical procedure for the treatment of cervical spondylotic myelopathy (CSM), but there are few studies on the changes in cervical sagittal balance. This study aimed to analyze the imaging and clinical data of patients who underwent LAMP and to explore the effect of this procedure on the cervical sagittal balance.

METHODS

This was a retrospective study of the patients who underwent LAMP between 01/2014 and 12/2017. The C0-C2 Cobb angle, sagittal vertical angle (SVA), C2-C7 Cobb angle, and T1-slope were measured. The Japanese Orthopaedic Association (JOA) score, neck disability index (NDI), and visual analog scale (VAS) were used.

RESULTS

There were 69 males and 39 females. The mean age was 61.3 ± 5.3 years. The C0-C2 Cobb angle increased from 11.3 ± 5.5° to 26.8 ± 4.8° (P = 0.186). The C2-C7 Cobb angle decreased from 13.9 ± 8.6° to 10.65 ± 10.7° P = 0.016). SVA increased from 21.0 ± 5.8 mm to 25.4 ± 11.5 mm (P = 0.001). The preoperative average JOA score was 11.1 ± 2.2 points, and the postoperative score was 14.0 ± 2.1 points, with an average improvement rate of JOA of 46.5 ± 3.8%. The NDI score decreased from preoperative 15.6 ± 5.4 points to 11.3 ± 7.9 points, and the VAS score was decreased from 4.6 ± 1.8 points to 3.3 ± 1.6 points (all P < 0.05).

CONCLUSION

LAMP improved the neurological function and quality of life of patients with CSM. The cervical vertebrae show a tendency of tilting forward, suggesting that overextension of the upper cervical vertebra might be used to maintain the center of gravity of the skull and horizontal vision.

Motion Preservation at All Costs? Multilevel Hinge Nonunion, Plate Breakage, and Intradural Plate Migration After Cervical Laminoplasty: A Case Report and Literature Review

BACKGROUND

Cervical laminoplasty is a motion-preserving procedure that addresses spinal cord compression and avoids postlaminectomy kyphosis associated with cervical laminectomy. The most common complications include C5 nerve palsy, axial neck pain, hinge nonunion, and premature closure. Plating is a relatively newer method of laminoplasty fixation that may provide greater stabilization postoperatively and reduce the risk of laminoplasty closure compared with less rigid (e.g., suture) fixation techniques. Although prior studies have reported low rates of laminar/lateral mass screw back out, plate breakage and migration have not been previously described in the literature. The purpose of this paper is to present a case of multilevel hinge nonunion, plate breakage, and plate fragment migration. Although rare, plate failure may result in a dural tear and spinal cord injury/compression.

CASE DESCRIPTION

In this case, a 61-year-old man with a history of cervical spondylotic myelopathy treated with C3-7 laminoplasty 7 years prior presented to our hospital with severe headaches and electrical-type pain through the left upper and lower extremities. Imaging studies revealed several broken laminoplasty plates and intradural migration of a fragment of the C7 plate.

CONCLUSIONS

We provide recommendations for preventing hinge nonunion because resultant micromotion likely contributed to the plate breakages observed in this patient.

Cervical rotation before and after hinge-door cervical laminoplasty for cervical spondylotic myelopathy

Background:

Hinge-Door Cervical laminoplasty is commonly performed procedure in patients with cervical spondylotic myelopathy. Most available studies have established restriction of flexion and extension motion post laminoplasty but the literature on post-laminoplasty axial rotation is sparse.

Objective:

To study the axial neck rotation on either side following hinge door cervical laminoplasty.

Materials and Methods:

Twenty consecutive patients of cervical spondylotic myelopathy planned for cervical laminoplasty were included in the study. Preoperative and postoperative radiological data was recorded for each patient and analysed by an experienced neuroradiologist. The clinical and radiological follow-up was recorded at 6 months post surgery. All patients underwent standard hinge door C3-C6 laminoplasty preserving the muscle attachments to C2 and C7 vertebra.

Results:

There were 13 men and 7 women with a mean age of 60.5 years, age range 58-70 years. The mean preop C1 C2 rotation was 46.5 degrees and mean post-operative C1-C2 rotation was 44.3 degrees. The average subaxial cervical spine rotation was 11.66 degrees preoperatively and 12.47 degrees postoperatively. The global cervical spine rotation was 80.95 degrees preoperatively and 76.82 degrees postoperatively. There is no significant change in segmental, subaxial and global cervical spine rotation following hinge door C3-C6 laminoplasty preserving the muscle attachments to C2 and C7 vertebra.

Conclusion:

Cervical laminoplasty preserves cervical ROM and is a motion-preserving surgery as far as axial rotation is concerned.

Impact of global spine balance and cervical regional alignment on determination of postoperative cervical alignment after laminoplasty

The aim of this study is to analyze the combined impact of preoperative T1 slope (T1S) and C2-C7 sagittal vertical axis (C2-C7 SVA) on determination of cervical alignment after laminoplasty.Forty patients undergoing laminoplasty for cervical spondylotic myelopathy (CSM) with more than 2 years follow-up were enrolled. Three parameters, including cervical lordosis, T1S, and C2-C7 SVA, were measured by preoperative and postoperative radiographs. Receiver operating characteristics (ROC) curve analysis was used to determine the optimal cut-off values of preoperative T1S and C2-C7 SVA for predicting postoperative loss of cervical lordosis. Patients were classified into 4 categories based on cut-off values of preoperative T1S and C2-C7 SVA. The primary outcome was postoperative C2-C7 SVA. Change in radiographic parameters between 4 groups were compared and analyzed.Optimal cut-off values for predicting loss of cervical lordosis were T1S of 20 degrees and C2-C7 SVA of 22 mm. Patients with small C2-C7 SVA, no matter what the value of T1S, got slight loss of cervical lordosis and increase in C2-C7 SVA. Patients with low T1S and large SVA (T1 ≤20° and SVA >22 mm) got postoperative correction of kyphosis and decrease of C2-C7 SVA. However, patients with high T1S and large SVA (T1 >20° and SVA >22 mm) got mean postoperative C2-C7 SVA value of 37.06 mm, close to the threshold value of 40 mm.Determination of cervical alignment after laminoplasty relies on the equilibrium between destruction of cervical structure, kyphotic force, and adaptive compensation of whole spine, lordotic force. Lower T1S means bigger compensatory ability to adjust different severity of cervical sagittal malalignment, and vice versa.

Cervical sagittal balance parameters after single-level anterior cervical discectomy and fusion: Correlations with clinical and functional outcomes

Background:

Normal sagittal cervical alignment has been associated with improved outcome after anterior cervical discectomy and fusion (ACDF).

Objective:

The aim of this study is to identify alterations of cervical sagittal balance parameters after single-level ACDF and assess correlations with postoperative functionality.

Methods:

A retrospective chart review was performed between January 2010 and January 2014 to identify adult patients with no previous cervical spine surgery who underwent ACDF at any one level between C2 and C7 for the single-level degenerative disease. Tumor, infection, and trauma cases were excluded from the study. For the included cases, the following data were recorded preoperatively and 6 months–1 year after surgery: sagittal balance-marker measurements of the C1–C2 angle, C2–C7 angle, C7 slope, segmental angle at the operated level, and sagittal vertical axis (SVA) distance between C2 and C7, as well as the neck disability index and visual analog scale of pain.

Results:

The present study included 47 patients (average age: 51.2 years; range: 28–86 years). A moderate negative correlation between a smaller C2–C7 angle and the presence of right arm pain before treatment was found (P = 0.0281). Postoperatively, functionality scores significantly improved in all patients. C1–C2 angle increased with statistical significance (P = 0.0255). C2–C7 angle, segmental angle, C7 slope, and SVA C2–C7 distance did not change with statistical significance after surgery. C7 slope significantly correlated with overall cervical sagittal balance (P < 0.05).

Conclusions:

Single-level ACDF significantly increases upper cervical lordosis (C1–C2) without significantly changing lower cervical lordosis (C2–C7). The C7 slope is a significant marker of overall cervical sagittal alignment (P < 0.05).

Cervical Paraspinal Muscle Atrophy Rates Following Laminoplasty and Laminectomy with Fusion for Cervical Spondylotic Myelopathy

BACKGROUND

Cervical spondylotic myelopathy (CSM) is a disorder that can cause neurologic deterioration. Studies on paraspinal muscular atrophy (PMA) in the lumbar spine have shown that these changes are caused by several perioperative factors. It is possible that PMA in the cervical spine could behave similarly. In this retrospective study, we compared the degree of PMA after laminoplasty versus laminectomy and fusion (LF) using a standard posterior approach to the cervical spine.

METHODS

18 laminoplasty and 43 LF patients were included in this study. For each patient, preoperative and postoperative MRI files were obtained and transferred into OsiriX imaging software. Atrophy rate was obtained and reported as percentage change in cross-sectional area of the cervical paraspinal muscles from preoperative to postoperative imaging.

RESULTS

Mean cross-sectional cervical muscle atrophy rates were 6% and 13.1% for laminoplasty and LF, respectively, representing a 2.19 times increase in the degree of atrophy (P < 0.001). Independently, LF was associated with a 5.84% increase in the rate of PMA (P = 0.03). Involvement of C3 as the cephalad surgical level was associated with a 5.78% decrease in the rate of PMA (P = 0.03). For each degree increase in postoperative Cobb angle, there was a 0.66% decrease in the rate of PMA (P = 0.02).

CONCLUSION

PMA should be part of the decision making process when a posterior approach is considered, inasmuch as this study demonstrates that cervical laminoplasty was associated with significantly lower rates of PMA compared with cervical laminectomy and fusion. Additionally, these results suggest that minimizing PMA may help preserve cervical lordosis.

540° Cervical Realignment Procedure for Extensive Cervical OPLL With Kyphotic Deformity

STUDY DESIGN

A retrospective study.

OBJECTIVE

The aim of this study was to present a novel, two-stage [posterior and anterior-posterior (P-AP) 540°] procedure for extensive cervical ossification of the longitudinal ligament (OPLL) with kyphotic deformity.

SUMMARY OF BACKGROUND DATA

The optimal surgical strategy for extensive cervical OPLL remains a controversial issue. Neurological injury and dural defect are complications of anterior surgery, while a posterior surgery can lead to poor clinical outcomes related to incomplete decompression.

METHODS

We analyzed consecutive cases of patients who underwent procedure described herein, which consists of two stages: the first (P: laminectomy and facet release with segmental screw fixations without rod assembly) and the second 1 week later (AP: multilevel anterior cervical discectomy with fusions (ACDFs) at the apex of the deformity without decompression, placement of lordotic grafts, and posterior fusion). To assess the radiographic parameters, extent of OPLL, maximal canal occupying ratio (%), the distances from the maximal compression to the K-line, and C2-7 angle were analyzed. Clinically, we analyzed visual analog scale of neck and arm pain, neck disability index (NDI), Japanese Orthopedic Association (JOA) score, and complications.

RESULTS

A total of 18 patients were enrolled (M:F = 15:3, mean age 64.5 yrs, mean follow-up was 30 months). The mean extent of the OPLL was 3.8 vertebral body levels. Posterior fusion was performed on a mean 4.5 segments and anterior fusion was on a mean 2.4 segments. The mean C2-7 Cobb angle was improved from 10.5° to -12.2° at follow-up. The K-line distance to the maximal compression and canal occupying ratio were improved from -3.3 mm, 73.5% to 3.8 mm, 38.4%, respectively. Preoperative NDI and JOA scores were significantly improved (18.5 to 9.4 and 8.2 to 14.8) at the last follow-up.

CONCLUSION

The 540° P-AP procedure could provide safe decompression, cervical realignment, and favorable outcomes without the disadvantages of the conventional anterior and/or posterior surgery for extensive cervical OPLL with kyphotic deformity.

LEVEL OF EVIDENCE

4.

Effect of Mini-plate Fixation on Hinge Fracture and Bony Fusion in Unilateral Open-door Cervical Expansive Laminoplasty

STUDY DESIGN

This was a retrospective study.

OBJECTIVE

The aim of this study was to investigate the effect of Centerpiece mini-plate fixation on the complete fracture and bony fusion of the hinge side in unilateral open-door cervical expansive laminoplasty.

SUMMARY OF BACKGROUND DATA

Cervical laminoplasty is an effective and safe surgery for cervical canal stenosis. The Centerpiece mini-plate is an instrument used to secure the laminae and maintain the cervical canal expansion. Stability of the new laminae is largely dependent on healing of the hinge side bone fracture and the degree of bony fusion. To date, few studies have reported on the effects of mini-plate fixation on these 2 important factors.

MATERIALS AND METHODS

Between September 2009 and March 2011, 58 patients received unilateral open-door cervical expansive laminoplasty at the authors' hospital. The group included 47 male and 11 female patients, with a mean age of 61 (range, 35-81) years. Two hundred twenty-five laminae were fixed using the Centerpiece mini-plate (group A), whereas 62 laminae were fixed using suture suspension (group B). The rates of fracture and bony fusion of the hinge were observed using computed tomography scan and compared between the 2 groups. The complete fractures were subdivided into 4 groups based on the degree of displacement of the fractured ends: type I (no displacement), type II (mild to moderate displacement), type III (complete displacement or separation), or type IV (the hinge had collapsed into the cervical canal).

RESULTS

The number of incomplete fractures and type I to IV fractures in group A were 95, 93, 25, 8, and 4 and 29, 25, 4, 2, 2 in group B, respectively. There were no significant differences between the 2 groups in terms of complete fracture rates (P=0.309) and complete fracture type distribution (P=0.694). Group A had a significantly higher rate of bony fusion of the hinge 3 months after surgery (82% vs. 70%, P=0.042); however, this rate was not statistically significant 6 months after surgery (P=0.141). For type I complete hinge fracture, group A had higher bony fusion rates, both 3 months (86% vs. 57%, P=0.004) and 6 months (92% vs. 85%, P=0.048) postoperatively. The rates of bony fusion were also significantly different among all complete fracture types 3 months (P<0.001) and 6 months (P<0.001) postoperatively.

CONCLUSIONS

Centerpiece mini-plate fixation in unilateral open-door cervical expansive laminoplasty might not increase the complete fracture rate compared with suture suspension and might promote bony fusion of type I complete hinge fractures.

En Bloc Cervical Laminoplasty Using Translaminar Screws (T-laminoplasty): Novel Procedure for Preserving Midline Ligamentous Structures

STUDY DESIGN

Prospectively maintained and retrospectively analyzed study.

OBJECTIVE

The authors have newly developed an en bloc cervical laminoplasty using translaminar screws (T-laminoplasty) to preserve the posterior midline structures so as to maintain spinal stability and prevent postoperative axial pain and deformity.

SUMMARY OF BACKGROUND DATA

Cervical laminoplasty is a popular surgical procedure for patients with multilevel compressive cervical lesions. However, several reports have noted its limitations and shortcomings.

METHODS

After exposure of the posterior cervical spine with preservation of the midline ligamentous structure, en bloc laminotomy was performed and made a laminectomized block. While the laminotomized block was being lifted, the translaminar trajectory from the lamina to the contralateral lateral mass was prepared. Then a translaminar screw was inserted with suspension of the laminotomized block to expand the spinal canal, passed through the laminar spacer, and finally fixed in the contralateral lateral mass. Next, another screw was inserted into the adjacent segment from the opposite side, and further screw fixations were made in this alternating manner.

RESULTS

Twenty patients underwent T-laminoplasty and 83 segments were operated upon. Clinical outcomes were statistically improved during the mean follow-up period of 19.7 months. Radiologic outcomes of cervical lordosis and range of motion were preserved with the expansion of the cross-sectional area of the spinal canal. In addition, no restenosis or laminar settlement was observed at the last follow-up.

CONCLUSIONS

T-laminoplasty can be one of the surgical options for multilevel compressive cervical lesions. With midline ligamentous structures preserving the procedure, it was possible to get enough canal decompression and foraminal decompression, while obtaining good clinical and radiologic outcomes.

Analysis of the morphometric characteristics of the cervical spine and its association with the development of temporomandibular disorders

OBJECTIVES

Temporomandibular disorders (TMD) are frequently observed in various populations. They affect both the temporomandibular joints and several associated structures such as the cervical spine. In this observational, descriptive, cross-sectional study, the authors assessed possible relationships between various cranio-cervical parameters and TMD.

METHOD

The study group consisted of 102 patients who were diagnosed with TMD and were treated at the Faculty of Dentistry of the University of Concepción, Chile. The control group was composed of 99 subjects without TMD, treated at other clinics of the University of Concepción.

RESULTS

The following relationships between TMD and cranio-cervical parameters were found to be statistically significant: TMD and inversion of the hyoid triangle (p = 0.0060); TMD and depth of cervical curvature (p = 0.0302); TMD and deformity of the cervical vertebrae (p = 0.0001).

DISCUSSION

The findings suggest a significant relationship between TMD findings and both cephalometric and morphometric parameters of the cervical spine.

Effect of lamina open angles in expansion open-door laminoplasty on the clinical results in treating cervical spondylotic myelopathy

STUDY DESIGN

A retrospective study.

OBJECTIVE

To evaluate and compare the relation of the efficacy and clinical results of expansion open-door laminoplasty (EOLP) with different angles in lamina open-door.

SUMMARY OF BACKGROUND DATA

EOLP is currently the most widely adopted surgical treatment for cervical spondylotic myelopathy. Although many long-term clinical follow-up studies have reported that most patients recover satisfactorily after EOLP, there have been numerous reports regarding postoperative complications, such as stubborn axial symptoms (AS) and C5 palsy. The lamina open-door angles in EOLP play a decisive role in determining the openness of the door that affects clinical outcomes. Nonetheless, no thorough studies on different angles in EOLP have been published.

METHOD

A total of 198 cervical spondylotic myelopathy patients who underwent posterior cervical EOLP and at least 24 months follow-up treatment between July 2006 and January 2009 were selected as case studies. Among the 198 cases used, there were 39 double-segment cases with the location being C3-C5 in 11 cases and C4-C6 in 28 cases, 97 three-segments (C4-C7) and 62 four segments (C3-C7). All of the patients underwent x-ray, computed tomography, and magnetic resonance imaging images for evaluation of the cervical spine. According to different opening angles, measured by computed tomography scan after operation 1 week, the patients were divided into 2 groups, group A (>30 degrees, 76 patients including 44 males and 32 females) and group B (15-30 degrees, 122 patients including 71 males and 51 females). All patients were followed up for over 24 months, clinical results including operative duration, intraoperative bleeding volume, postoperative complications, C2-C7 Cobb angle, cervical curvature index (CI), range of motion (ROM), and values after the spinal cord backward shift were analyzed statistically, evaluating the neurological function at final follow-up and calculating the improvement rate of nerve function recovery.

RESULTS

There was no statistically significant difference (P>0.05) between the 2 groups in the following areas: the Japanese Orthopedic Association scores, C2-C7 Cobb angle, cervical CI, and ROM. In addition, operative duration and intraoperative bleeding volume between A group and B group showed no significant differences (P>0.05). After surgery, 51 patients (67.1%) in group A had AS, 8 patients (10.4%) had C5 palsy, and 1 patient had mild cervical kyphosis. Whereas postoperatively group B contained 37 cases (10.5%) with AS, 3 (2.4%) with C5 palsy, and in 4 cases (3.28%) the lamina open-door had reclosed. The rate of patients with AS and C5 palsy in group A was higher than group B. The incidence of postoperative complications between the 2 groups have a significant difference (P<0.05). The rate of improvement of Japanese Orthopedic Association scores in last follow-up between group A and group B did not reach statistical significance (P>0.05). At the 1-month follow-up the range of the value of spinal cord backward shift was 0-7.95 mm with the average being 2.41±0.46 mm. C2-C7 Cobb angle, CI, and ROM between the 2 groups revealed no statistical significance (P>0.05). ROM comparisons preoperatively and postoperatively between the 2 groups were significantly different (P<0.05).

CONCLUSIONS

In different angles of lamina open-door, the improvement rate of neurological function after surgery had no statistically significant difference between 2 groups. When the open-door angle is maintained between 15 and 30 degrees, it can reduce the incidence of C5 palsy in the hinge side and AS, but we should prevent reclosure of the lamina open-door.

Combined expansive open-door laminoplasty with short-segment lateral mass instrumented fusion for multilevel cervical spondylotic myelopathy with short segment instability

OBJECTIVES

Expansive open-door laminoplasty (EOLP) is an effective procedure for multilevel cervical spondylotic myelopathy (MCSM). It preserves a higher range of cervical motion than laminectomy with fusion and reserves more posterior elements than laminectomy alone. MCSM with short-segment instability or correctable local kyphosis often requires long-segment decompression and adequate segment fusion.

MATERIALS AND METHODS

We retrospectively reviewed 20 patients who received EOLP with short-segment posterior lateral mass instrumented fusion at our institution from 2008 to 2011. The follow-up period was at least 36 months. Postoperative functional and radiographic outcomes were collected and analyzed.

RESULTS

Japanese Orthopedic Association scores improved significantly 36 months after surgery and the average recovery ratio was 85.3 ± 14.7%. Nurick disability scores and neck pain visual analog scale scores considerably decreased 3 years after surgery. No patients had aggravated neck pain or C5 nerve palsy during follow-up. The preservation of range of motion was approximately 60% after 36 months. No implant loosening or laminar collapse was reported on radiographic follow-up.

CONCLUSION

EOLP with concomitant lateral mass instrumented fusion yields favorable short-term clinical results for MCSM with short segment instability.

Cervical Laminoplasty: The History and the Future

Cervical laminoplasty was developed as an alternative to cervical laminectomy for treatment of cervical myelopathy, in which hinges are created to lift the lamina. Various techniques of laminoplasty have since been developed after two prototype techniques: Hirabayashi’s open-door laminoplasty and Kurokawa’s spinous process splitting (double-door) laminoplasty. Several in vitro studies report superior biomechanical stability of the cervical spine after laminoplasty compared with laminectomy. In clinical situation, randomized control studies are scarce and superiority of one procedure over another is not uniformly shown. Lack of hard evidence supporting the purported advantages of laminoplasty over laminectomy, that is, reduced rate of postoperative instability and kyphosis development, while preserving range of motion (ROM), has been a weak selling point. Currently, laminoplasty is performed by majority of spine surgeons in Japan, but is rarely performed in the United States and Europe. Recent development in laminoplasty is preservation of muscle attachment, which enabled dynamic stabilization of the cervical spine by neck extensor muscles. After treatment with new laminoplasty techniques with active postoperative neck ROM exercises, postoperative instability, kyphosis, axial neck pain, and loss of ROM seems minimal. Well-designed clinical trials to show the effectiveness and long-term outcome of this surgical procedure are warranted.

Does preoperative T1 slope affect radiological and functional outcomes after cervical laminoplasty?

STUDY DESIGN

Retrospective comparative study.

OBJECTIVE

To analyze changes in the clinical and radiological factors related to cervical sagittal balance, relative to preoperative T1 slope, in patients with cervical myelopathy after laminoplasty (LP).

SUMMARY OF BACKGROUND DATA

T1 slope is an important factor that should be considered before LP. However, until now, there have been no studies on how preoperative T1 slope affects the sagittal balance of cervical spine and various functional outcomes after LP.

METHODS

Seventy-six patients with cervical myelopathy (M:F ratio = 50:26; mean age = 64.7 ± 9.1 yr) underwent a cervical LP and were followed for more than 2 years. Radiological measurements were performed to analyze the following parameters: (1) C2-C7 sagittal vertical axis; (2) T1 slope; (3) C2-C7 lordosis; and (4) thoracic kyphosis. The visual analogue scale, Japanese Orthopedic Association, neck disability index, and 36-Item Short-Form Health Survey were also investigated. Patients were divided into 2 groups according to preoperative T1 slope, with the cutoff value being the median preoperative T1 slope. Changes in clinical and radiological parameters were compared between the preoperative evaluation and final visit.

RESULTS

Overall, C2-C7 sagittal vertical axis increased from 21.2 to 24.5 mm (P = 0.004) and C2-C7 lordosis decreased from 13.9° to 10.3° (P = 0.007) postoperatively. The T1 slope did not show any postoperative differences. Preoperative C2-C7 lordosis was larger in the high-T1 group (19.1°) than in the low-T1 group (9.0°). However, postoperative changes in C2-C7 sagittal vertical axis and C2-C7 lordosis did not show any between-group differences. Clinical outcomes (except neck pain) demonstrated overall improvement in both groups. Comparing changes in both groups showed no differences in neck pain, arm pain, neck disability index, or 36-Item Short-Form Health Survey physical component score between groups.

CONCLUSION

Cervical sagittal balance is compromised after cervical LP. However, the degree of aggravation does not correlate with the preoperative T1 slope. Most clinical parameters demonstrate overall improvement regardless of preoperative T1 slope.

LEVEL OF EVIDENCE

3.

In vivo 3D kinematic changes in the cervical spine after laminoplasty for cervical spondylotic myelopathy

Object

Cervical laminoplasty is an effective procedure for decompressing the spinal cord at multiple levels, but restriction of neck motion is one of the well-known complications of the procedure. Although many authors have reported on cervical range of motion (ROM) after laminoplasty, they have focused mainly on 2D flexion and extension on lateral radiographs, not on 3D motion (including coupled motion) nor on precise intervertebral motion. The purpose of this study was to clarify the 3D kinematic changes in the cervical spine after laminoplasty performed to treat cervical spondylotic myelopathy.

Methods

Eleven consecutive patients (6 men and 5 women, mean age 68.1 years, age range 57–79 years) with cervical spondylotic myelopathy who had undergone laminoplasty were included in the study. All patients underwent 3D CT of the cervical spine in 5 positions (neutral, 45° head rotation left and right, maximum head flexion, and maximum head extension) using supporting devices. The scans were performed preoperatively and at 6 months after laminoplasty. Segmental ROM from Oc–C1 to C7–T1 was calculated both in flexion-extension and in rotation, using a voxel-based registration method.

Results

Mean C2–7 flexion-extension ROM, equivalent to cervical ROM in all previous studies, was 45.5° ± 7.1° preoperatively and 35.5° ± 8.2° postoperatively, which was a statistically significant 33% decrease. However, mean Oc–T1 flexion-extension ROM, which represented total cervical ROM, was 71.5° ± 8.3° preoperatively and 66.5° ± 8.3° postoperatively, an insignificant 7.0% decrease. In focusing on each motion segment, the authors observed a statistically significant 22.6% decrease in mean segmental ROM at the operated levels during flexion-extension and a statistically insignificant 10.2% decrease during rotation. The most significant decrease was observed at C2–3. Segmental ROM at C2–3 decreased 24.2% during flexion-extension and 21.8% during rotation. However, a statistically insignificant 37.2% increase was observed at the upper cervical spine (Oc–C2) during flexion-extension. The coupling pattern during rotation did not change significantly after laminoplasty.

Conclusions

In this first accurate documentation of 3D segmental kinematic changes after laminoplasty, Oc–T1 ROM, which represented total cervical ROM, did not change significantly during either flexion-extension or rotation by 6 months after laminoplasty despite a significant decrease in C2–7 flexion-extension ROM. This is thought to be partially because of a compensatory increase in segmental ROM at the upper cervical spine (Oc–C2).

Anterior decompressive surgery after cervical laminoplasty in patients with ossification of the posterior longitudinal ligament

BACKGROUND CONTEXT

Two surgical procedures, posterior decompressive surgery (PDS) and anterior decompressive surgery (ADS), are the treatment options for cervical ossification of the posterior longitudinal ligament (OPLL). Each procedure has advantages and disadvantages. Cervical laminoplasty, a type of PDS, is relatively easy to perform and can be used for patients with multilevel cord compression. ADS can often be more technically demanding.

OBJECTIVE

The purpose of this study was to clarify the clinical characteristics and surgical results of the patients for whom ADS was necessary after PDS.

STUDY DESIGN

Retrospective study.

METHODS

A total of 144 patients, followed for more than 3 years after cervical laminoplasty, were included. The neurologic status was graded using the Japanese Orthopedic Association (JOA score). Eleven patients underwent ADS after PDS. The clinical background and surgical outcomes were evaluated. Radiological findings of the 11 patients requiring ADS after PDS (PA group) and the 133 PDS patients not requiring ADS (P group) were compared.

RESULTS

In the PA group, the JOA score was slightly deteriorated during follow-up after cervical laminoplasty. Severe pain in the unilateral upper extremity and deterioration of cervical myelopathy were the most typical symptoms necessitating ADS. The incidence of the mixed type of OPLL was significantly higher in this group. The JOA score improved in all patients after ADS as a second surgery.

CONCLUSIONS

In our strategy for the surgical treatment of cervical OPLL, PDS with laminoplasty remains as the initial treatment, and in patients with neurological deterioration and newly developed clinical symptoms during follow-up, ADS is considered as a salvage procedure.

Is there a difference in range of motion, neck pain, and outcomes in patients with ossification of posterior longitudinal ligament versus those with cervical spondylosis, treated with plated laminoplasty?

OBJECT

There are little data on the effects of plated, or plate-only, open-door laminoplasty on cervical range of motion (ROM), neck pain, and clinical outcomes. The purpose of this study was to compare ROM after a plated laminoplasty in patients with ossification of posterior longitudinal ligament (OPLL) versus those with cervical spondylotic myelopathy (CSM) and to correlate ROM with postoperative neck pain and neurological outcomes.

METHODS

The authors retrospectively compared patients with a diagnosis of cervical stenosis due to either OPLL or CSM who had been treated with plated laminoplasty in the period from 2007 to 2012 at the University of California, San Francisco. Clinical outcomes were measured using the modified Japanese Orthopaedic Association (mJOA) scale and neck visual analog scale (VAS). Radiographic outcomes included assessment of changes in the C2-7 Cobb angle at flexion and extension, ROM at C2-7, and ROM of proximal and distal segments adjacent to the plated lamina.

RESULTS

Sixty patients (40 men and 20 women) with an average age of 63.1 ± 10.9 years were included in the study. Forty-one patients had degenerative CSM and 19 patients had OPLL. The mean follow-up period was 20.9 ± 13.1 months. The mean mJOA score significantly improved in both the CSM and the OPLL groups (12.8 to 14.5, p < 0.01; and 13.2 to 14.2, respectively; p = 0.04). In the CSM group, the mean VAS neck score significantly improved from 4.2 to 2.6 after surgery (p = 0.01), but this improvement did not reach the minimum clinically important difference (MCID). Neither was there significant improvement in the VAS neck score in the OPLL group (3.6 to 3.1, p = 0.17). In the CSM group, ROM at C2-7 significantly decreased from 32.7° before surgery to 24.4° after surgery (p < 0.01). In the OPLL group, ROM at C2-7 significantly decreased from 34.4° to 20.8° (p < 0.01). In the CSM group, the change in the VAS neck score significantly correlated with the change in the flexion angle (r = - 0.31) and the extension angle (r = - 0.37); however, it did not correlate with the change in ROM at C2-7 (r = - 0.1). In the OPLL group, the change in the VAS neck score did not correlate with the change in the flexion angle (r = 0.03), the extension angle (r = - 0.17), or the ROM at C2-7 (r = - 0.28). The OPLL group had a significantly greater loss of ROM after surgery than did the CSM group (p = 0.04). There was no significant correlation between the change in ROM and the mJOA score in either group.

CONCLUSIONS

Plated laminoplasty in patients with either OPLL or CSM decreases cervical ROM, especially in the extension angle. Among patients who have undergone laminoplasty, those with OPLL lose more ROM than do those with CSM. No correlation was observed between neck pain and ROM in either group. Neither group had a change in neck pain that reached the MCID following laminoplasty. Both groups improved in neurological function and outcomes.

Evaluation of Cervical Spine Posture After Functional Therapy with FR-2: A Longitudinal Study

The authors compared postural changes produced in 20 Caucasian female children treated with the Frankel Functional Regulator appliance (FR-2) (Frankel Industries, Morangis Cedex, France) using cephalometric tracings and comparing the tracings to 20 untreated Class II controls from the University of Chieti. Each patient in the study group was treated for exactly two years by the same operator using the FR-2 appliance and a standardized design and clinical technique, including prefunctional orthodontics where indicated. The average starting age was 8.4 yrs. (SD+/-2.1). At the end of the therapy, the average age was 10.3 yrs. (SD+/-2.4). Two teleradiographs were made of each patient: the first one at the beginning of treatment and the second one after six months. The radiographs were taken with the subjects standing in the ortho-position with no ear rods in the cephalostat; mirror position was carried out. In order to detect errors due to landmark identification, duplicate measurements were made using ten radiographs, and the error variance was calculated using Dahlberg's formula. Thirty-seven variables were studied. The cervical lordosis angle (CVT/EVT) was significantly higher in the study group as compared to the control group (p<0.05) at the end of treatment, probably due to a significant backward inclination of the upper segment of the cervical column (OPTNer and CVTNer) in the treated group (p<0.001 and p<0.01) from pre- to posttreatment. There was no significant change in the lower segment of the cervical column inclination (EVT/Ver). The changes resulted in a weak association in the multiple regression model to an increasing of maxillary base length and mandibular protrusion (R2=0.272; p<0.05). Other variables in the multiple regression were not significant.

C-5 palsy after cervical laminoplasty with instrumented posterior fusion

Object

Postoperative C-5 palsy is known as a common complication after cervical laminoplasty. The authors of this article have encountered postoperative C-5 palsy more often when laminoplasty was combined with instrumented posterior spinal fusion than when it was performed alone. The purpose of this clinical study was to examine the incidence of fifth cervical nerve root palsy (C-5 palsy) and surgical results in patients with cervical myelopathy who had undergone laminoplasty with or without instrumented spinal fusion.

Methods

The authors retrospectively studied patients with cervical myelopathy who had undergone laminoplasty with or without instrumented posterior spinal fusion.

Results

Clinical data on 58 patients were evaluated and analyzed. Preoperative diagnoses were cervical spondylotic myelopathy or ossification of the posterior longitudinal ligament of the cervical spine. Twenty-four patients with spondylolisthesis or kyphosis underwent laminoplasty combined with posterior spinal fusion using instrumented lateral mass fixation (fusion group), while the remaining 34 patients underwent laminoplasty without posterior spinal fusion (no-fusion group). In the fusion group, C-5 palsy developed in 6 patients; in the no-fusion group, it occurred in only 1 patient. There was a significant difference in the rate of this complication between the 2 groups. In the fusion group, local kyphosis and spondylolisthesis level were reduced at the fusion level, and all patients with C-5 palsy underwent C4–5 spinal fusion.

Conclusions

The incidence of postoperative C-5 palsy is significantly higher after laminoplasty when it is combined with spinal fusion. Correction of kyphosis and spondylolisthesis using posterior instrumentation may be a risk factor for iatrogenic intervertebral foraminal stenosis leading to C-5 palsy.

T1 slope as a predictor of kyphotic alignment change after laminoplasty in patients with cervical myelopathy

STUDY DESIGN

Prospective study.

OBJECTIVE

To analyze the effect of T1 slope on kyphotic alignment change after cervical laminoplasty in patients with cervical myelopathy.

SUMMARY OF BACKGROUND DATA

Laminoplasty is a posterior method, and maintenance of both preoperative and postoperative lordotic alignment is prerequisite for the successful surgery. Unfortunately, patients who underwent laminoplasty tend to have kyphotic alignment change after operation despite sufficient preoperative lordosis, and such kyphotic alignment change after cervical laminoplasty can reduce surgical outcome and require additional surgery.

METHODS

Consecutive patients who underwent cervical laminoplasty for cervical myelopathy were enrolled. Cervical spine lateral radiography in neutral, flexion, and extension were taken before surgery and at 2-year follow-up. Patients were divided into 2 groups according to the preoperative T1 slope, and postoperative cervical alignment change was compared according to the preoperative T1 slope.

RESULTS

A total of 51 patients were enrolled in this study. The mean age was 57.2 years (range, 39-88 yr). There were 39 male patients and 12 female patients. There were no differences in age, sex, the presence and type of ossification of posterior longitudinal ligament, and operation level between the patients with higher and lower preoperative T1 slope. Patients with higher preoperative T1 slope had more lordotic preoperative cervical alignment; however, they had more kyphotic alignment changes after laminoplasty (P < 0.001). After univariate logistic regression, only higher preoperative T1 slope was associated with significantly increased odds ratio for postoperative kyphotic alignment changes.

CONCLUSION

We hypothesized that kyphotic alignment change by posterior structural injury after cervical laminoplasty would be more marked in patients with high T1 slope, and demonstrated that patients with cervical myelopathy with high T1 slope had more kyphotic alignment changes after cervical laminoplasty at 2-year follow-up.

Full-endoscopic cervical arcocristectomy for the treatment of spinal stenosis: results of a cadaver study

PURPOSE

Cervical spondylotic myelopathy is a multifactorial disease that is directly correlated by the degree of spinal stenosis. Surgery remains the best therapy. A posterior approach is often recommended in patients with multilevel dorsal cervical compression. Aim of the present experimental study was to evaluate the feasibility of a full-endoscopic arcocristectomy in a cadaver study.

METHODS

We performed full-endoscopic arcocristectomy on ten formalin-fixed human cervical specimens. Before and after decompression we obtained high-resolution computerized tomography (CT) data to evaluate the diameter of the cervical spinal canal.

RESULTS

Overall, surgery was possible on 55 segments in ten cadaver specimens. A mean increase of 4.1 mm (±1.2 mm) in the sagittal diameter of the cervical spinal canal could be achieved (p < 0.05, t test).

CONCLUSIONS

The full-endoscopic arcrocristectomy is feasible and achieves a sufficient decompression. This minimal invasive technique protects most of the dorsal structures and therefore probably preserves biomechanical functions, which has to be proven in future studies.

Expansive open-door laminoplasty and selective anterior cervical decompression and fusion for treatment of multilevel cervical spondylotic myelopathy

OBJECTIVE

To evaluate the clinical results of combined expansive open-door laminoplasty by splitting of spinous processes and selective anterior cervical decompression and fusion in treatment of multilevel severe cervical spondylotic myelopathy (CSM).

METHODS

Twenty-eight patients (16 men and 12 women) underwent one-stage combined expansive open-door laminoplasty and selective anterior decompression and fusion for severe CSM; the average patient age was 51.3 years (range, 32-63 years). Clinical results were assessed by Japanese Orthopaedic Association (JOA) scores, number of finger grip and releases (G and R) in ten seconds, hand-grip strength, visual analog scale (VAS) of axial pain, and C2-C7 angle.

RESULTS

  There was no worsening of neurological symptoms due to cord injury, cerebrospinal fluid leakage, or wound infection. All cases completed one-year follow-up. The JOA scores, number of G and R in ten seconds, and hand-grip strength were all significantly improved (P < 0.05). Satisfactory decompression was shown by MRI or CT to have been achieved in all cases. The C2-C7 angle did not differ significantly from that found pre-operatively. The axial neck pain score was 2.0 ± 0.1 on VAS.

CONCLUSION

Combined expansive open-door laminoplasty by splitting of spinous processes and selective anterior decompression and fusion achieves complete spinal canal decompression with minimal morbidity; this strategy is effective in improving the surgical outcomes of CSM in one-year follow-up.

Changes in the range of motion of the cervical spine and adjacent segments at ≥24 months after uninstrumented corpectomy for cervical spondylotic myelopathy

BACKGROUND

Few clinical studies have described the changes in the range of motion (ROM) of the cervical spine and adjacent segments following central corpectomy. We aimed to quantify the changes in range of motion (ROM) of the cervical spine and the adjacent segments at ≥24 months following uninstrumented central corpectomy (CC) for cervical spondylotic myelopathy (CSM) and to determine the contribution of the adjacent segments to the compensation for loss of motion of the cervical spine following CC.

METHODS

Preoperative and follow-up lateral cervical spine radiographs of 36 patients who underwent CC for CSM between 2001 and 2007 were compared for the ROM of the subaxial cervical spine, superior and inferior adjacent segment. Anterior osteophytes as seen on the radiographs were classified according to Nathan's grading system.

RESULTS

The mean duration of follow-up was 48.5 months. At follow-up, the total cervical spine ROM decreased by 18.3° ± 2.2° (p < 0.001), the superior adjacent segment ROM increased by 2.3° ± 0.9° (p = 0.01) and the inferior adjacent segment ROM, measured in 20 cases, increased by 6.2° ± 1.7° (p = 0.01). The superior adjacent segment showed a 70% increase, whereas the inferior adjacent segment showed a 110% increase in mobility. Nathan's grade at the superior or inferior adjacent segment increased in 12 cases.

CONCLUSIONS

CC significantly reduces the motion of the cervical spine and increases the adjacent segment mobility at intermediate follow-up. The inferior adjacent segment shows greater compensation of motion as compared to the superior adjacent segment in our series. Adjacent segment degeneration as estimated by Nathan's grade was seen in one-third of the cases.

Multidirectional flexibility of the spine following posterior decompressive surgery after single-level cervical disc arthroplasty: an in vitro biomechanical investigation

STUDY DESIGN

In vitro human cadaveric biomechanical study.

OBJECTIVE

This study quantifies the multidirectional flexibility of the spine following laminoplasty and laminectomy after cervical disc arthroplasty.

SUMMARY OF BACKGROUND DATA

Posterior decompressive surgery may be used to treat recurrence of myeloradiculopathy following disc arthroplasty. This is the first study investigating the biomechanical effects of posterior decompressive surgery combined with cervical disc arthroplasty.

METHODS

Seven human cervical spines were biomechanically evaluated under the following conditions: (1) intact; (2) discectomy (C5-C6); (3) disc arthroplasty (C5-C6); (4) arthroplasty + 3-level laminoplasty (C3-C5); (5) arthroplasty + 4-level laminoplasty (C3-C6); (6) arthroplasty + 5-level laminoplasty (C3-C7); (7) arthroplasty + 5-level laminoplasty (C3-C7) without hydroxyapatite spacers; and (8) arthroplasty + laminectomy (C3-C7). Multidirectional flexibility testing used unconstrained pure moments of ±2 Nm for flexion-extension, axial rotation, and lateral bending. Quantification of C5-C6 and C3-C7 range of motion (ROM) and neutral zone (NZ) were normalized to the intact spine (100%).

RESULTS

Flexion-extension loading of the discectomy condition demonstrated ROM of 22.05° ± 4.17° at the operative level (P < 0.05). Implantation of the porous coated motion device restored segmental motion near the intact condition (ROM, 9.97° ± 6.44°; NZ, 5.82° ± 6.18°). There were no statistical differences between 3-level (13.79° ± 6.49°), 4-level (14.51° ± 5.76°), and 5-level (15.67° ± 5.71°) laminoplasty; however, additional levels demonstrated a trend toward increased motion at the arthroplasty level. Laminoplasty without spacers (17.45°) and laminectomy (18.27°) indicated even greater segmental motion (P > 0.05). Axial rotation and lateral bending indicated trends similar to those for flexion-extension.

CONCLUSION

Posterior decompressive surgery increased ROM and NZ in all loading modes compared to arthroplasty alone, and laminectomy markedly increased motion compared with laminoplasty. Use of hydroxyapatite spacers and minimization of the extent of laminoplasty appear to be biomechanically favorable in this in vitro model.

Axial neck pain after cervical laminoplasty

OBJECTIVE

It has been demonstrated that cervical laminoplasty is an effective and safe method of treating multi-level cervical spondylotic myelopathy and ossification of the posterior longitudinal ligament. However, recent reports have suggested that axial neck pain is frequently encountered after cervical laminoplasty. The aim of the present study was to determine clinical significance of the C7 spinous process on axial neck pain after cervical laminoplasty.

METHODS

A total of 31 consecutive patients that underwent cervical laminoplasty between March 2002 and December 2008 were reviewed. The authors evaluated and compared axial neck pain and lordotic angle in patients that underwent C7 spinous process preserving surgery (group 1, n = 16) and in patients in which the C7 spinous process was sacrificed (group 2, n = 15).

RESULTS

Severe or moderate early axial pain occurred in 56.2% of patients in group 1 and in 86.6% in group 2. Severe or moderate late axial pain occurred in 12.5% in group 1 and in 73.3% in group 2. Eighty-Six percent of patients in group 2 and 43% in group 1 experienced aggravation of their axial neck pain during the early postoperative period. Aggravation of axial neck pain during early postoperative period was less common in group 1 but not statistically significant (p = 0.073). Sixty-six percent of patients in group 2 and 12% in group 1 had aggravated axial neck pain at late postoperative period and aggravation of late axial neck pain was significantly less common in group 1 (p = 0.002).

CONCLUSION

The present study demonstrates that C7 spinous process preserving laminoplasty decreases the incidence of aggravated axial neck pain after cervical laminoplasty.

Cervical laminoplasty for the treatment of cervical degenerative myelopathy

OBJECT

The objective of this systematic review was to use evidence-based medicine to examine the efficacy of cervical laminoplasty in the treatment of cervical spondylotic myelopathy (CSM).

METHODS

The National Library of Medicine and Cochrane Database were queried using MeSH headings and keywords relevant to cervical laminoplasty and CSM. Abstracts were reviewed and studies meeting the inclusion criteria were selected. The guidelines group assembled an evidentiary table summarizing the quality of evidence (Classes I-III). Disagreements regarding the level of evidence were resolved through an expert consensus conference. The group formulated recommendations that contained the degree of strength based on the Scottish Intercollegiate Guidelines network. Validation was done through peer review by the Joint Guidelines Committee of the American Association of Neurological Surgeons and Congress of Neurological Surgeons.

RESULTS

Cervical laminoplasty has improved functional outcome in the setting of CSM or ossification of the posterior longitudinal ligament. Using the Japanese Orthopaedic Association scale score, approximately 55-60% average recovery rate has been observed (Class III). The functional improvement observed after laminoplasty may be limited by duration of symptoms, severity of stenosis, severity of myelopathy, and poorly controlled diabetes as negative risk factors (Class II). There is conflicting evidence regarding age, with 1 study citing it as a negative risk factor, and another not demonstrating this result.

CONCLUSIONS

Cervical laminoplasty is recommended for the treatment of CSM or ossification of the posterior longitudinal ligament (Class III).

Preservation of the nuchal ligament plays an important role in preventing unfavorable radiologic changes after laminoplasty

STUDY DESIGN

Prospective study.

OBJECTIVE

To examine whether preservation of the funicular section of the nuchal ligament attached to the C6 and C7 spinous processes could prevent unfavorable radiologic changes such as kyphotic deformity and destabilization at the C6/7 segment, and to investigate possible correlations between adverse radiologic changes and neurologic recovery or incidence of axial neck pain after laminoplasty in patients with cervical spondylotic myelopathy.

SUMMARY OF BACKGROUND DATA

Adverse radiologic changes after cervical laminoplasty have been reported to result from detachment of cervical extensor muscles.

METHODS

Subjects comprised 37 patients who underwent modified C3-6 laminoplasty. Our procedure preserves the funicular section of the nuchal ligament attached to the C6 and/or C7 spinous processes in addition to all muscles attached to the C2 and C7 spinous processes and the subaxial deep extensor muscles on the hinged side. The funicular section of the ligament attached only to the C7 spinous process was preserved in 18 patients (C7 group). This funicular section attaching both to the C7 and C6 spinous processes was preserved in 19 patients (C6+7 group). Radiologic and clinical data were prospectively collected.

RESULTS

Postoperative loss of lordosis and destabilization at the C6/7 segment were significantly reduced in the C6+7 group compared with the C7 group. As of final follow-up, neurologic recovery was significantly poorer in the 3 patients with kyphosis than in the 34 patients with straight spinal alignment or lordosis. Frequencies of axial pain showed no significant differences between groups. This value did not vary with the differences in sagittal alignment.

CONCLUSIONS

These results indicate that the preserved funicular section of the nuchal ligament attached both to the C6 and C7 spinous processes plays an important role in preventing undesirable radiologic changes after laminoplasty.