Laminoplasty and skip laminectomy for cervical compressive myelopathy: range of motion, postoperative neck pain, and surgical outcomes in a randomized prospective study

Effect of preservation of the C-6 spinous process and its paraspinal muscular attachment on the prevention of postoperative axial neck pain in C3-6 laminoplasty

OBJECT

Axial neck pain after C3-6 laminoplasty has been reported to be significantly lesser than that after C3-7 laminoplasty because of the preservation of the C-7 spinous process and the attachment of nuchal muscles such as the trapezius and rhomboideus minor, which are connected to the scapula. The C-6 spinous process is the second longest spinous process after that of C-7, and it serves as an attachment point for these muscles. The effect of preserving the C-6 spinous process and its muscular attachment, in addition to preservation of the C-7 spinous process, on the prevention of axial neck pain is not well understood. The purpose of the current study was to clarify whether preservation of the paraspinal muscles of the C-6 spinous process reduces postoperative axial neck pain compared to that after using nonpreservation techniques.

METHODS

The authors studied 60 patients who underwent C3-6 double-door laminoplasty for the treatment of cervical spondylotic myelopathy or cervical ossification of the posterior longitudinal ligament; the minimum follow-up period was 1 year. Twenty-five patients underwent a C-6 paraspinal muscle preservation technique, and 35 underwent a C-6 nonpreservation technique. A visual analog scale (VAS) and VAS grading (Grades I-IV) were used to assess axial neck pain 1-3 months after surgery and at the final follow-up examination. Axial neck pain was classified as being 1 of 5 types, and its location was divided into 5 areas. The potential correlation between the C-6/C-7 spinous process length ratio and axial neck pain was examined.

RESULTS

The mean VAS scores (± SD) for axial neck pain were comparable between the C6-preservation group and the C6-nonpreservation group in both the early and late postoperative stages (4.1 ± 3.1 vs 4.0 ± 3.2 and 3.8 ± 2.9 vs 3.6 ± 3.0, respectively). The distribution of VAS grades was comparable in the 2 groups in both postoperative stages. Stiffness was the most prevalent complaint in both groups (64.0% and 54.5%, respectively), and the suprascapular region was the most common site in both groups (60.0% and 57.1%, respectively). The types and locations of axial neck pain were also similar between the groups. The C-6/C-7 spinous process length ratios were similar in the groups, and they did not correlate with axial neck pain. The reductions of range of motion and changes in sagittal alignment after surgery were also similar.

CONCLUSIONS

The C-6 paraspinal muscle preservation technique was not superior to the C6-nonpreservation technique for preventing postoperative axial neck pain.

Mid-term results of computer-assisted cervical pedicle screw fixation

Study Design

A retrospective study.

Purpose

The present study aimed to evaluate mid-term results of cervical pedicle screw (CPS) fixation for cervical instability.

Overview of Literature

CPS fixation has widely used in the treatment of cervical spinal instability from various causes; however, there are few reports on mid-term surgical results of CPS fixation.

Methods

Record of 19 patients who underwent cervical and/or upper thoracic (C2-T1) pedicle screw fixation for cervical instability was reviewed. The mean observation period was 90.2 months. Evaluated items included Japanese Orthopaedic Association (JOA) score and C2-7 lordotic angle before surgery and at 5 years after surgery. Postoperative computerized tomography was used to determine the accuracy of screw placement. Visual analog scale (VAS) for neck pain and radiological evidence of adjacent segment degeneration (ASD) at the 5-year follow-up were also evaluated.

Results

Mean JOA score was significantly improved from 9.0 points before surgery to 12.8 at 5 years after surgery (p=0.001). The C2-7 lordotic angle of the neutral position improved from 6.4° to 7.8° at 5 years after surgery, but this was not significant. The major perforation rate was 5.0%. There were no clinically significant complications such as vertebral artery injury, spinal cord injury, or nerve root injury caused by any screw perforation. Mean VAS for neck pain was 49.4 at 5 years after surgery. The rate of ASD was 21.1%.

Conclusions

Our mid-term results showed that CPS fixation was useful for treating cervical instability. Severe complications were prevented with the assistance of a computed tomography-based navigation system.

The relationship between laminoplasty opening angle and increased sagittal canal diameter and the prediction of spinal canal expansion following double-door cervical laminoplasty

PURPOSE

To clarify the relationship between laminoplasty opening angle (LOA) and the increase in sagittal canal diameter (SCD) in double-door cervical laminoplasty (DDCL) and to predict the increase in SCD using the resulting formula.

METHODS

We analyzed 20 patients with multilevel cervical spondylotic myelopathy who underwent DDCL between September 2010 and January 2013. The pre- and post-operative parameters of the cervical spinal canal were measured by computed tomography. We deduced a formula describing the relationship between LOA and the increase in SCD and used it to predict the increase in SCD of these patients as LOA increased.

RESULTS

When the C3-C7 LOA was 25°-45°, the magnitude of the increase in SCD was notable (increases of 3.08-5.6 mm compared with the pre-operative SCD). When the C3-C7 LOA was more than 45°, the magnitude of the increase in SCD was relatively smaller; the increase in C3-C7 SCD with a 55° LOA was merely 0.4 mm more than with a 45° LOA. When LOA was 30° at C3-C6 or 40° at C7, the increase in SCD was more than 4 mm. When the C3-C6 LOA was 40°, SCD increased by more than 5 mm.

CONCLUSIONS

The formula accurately showed the relationship between LOA and the increase in SCD in DDCL. Based on the LOA, increases in SCD following C3-C7 laminoplasty can be accurately predicted using this formula. This enables DDCL based on accurate individual LOAs, which prevents inadequate or excessive opening.

Laminoplasty and laminectomy hybrid decompression for the treatment of cervical spondylotic myelopathy with hypertrophic ligamentum flavum: a retrospective study

OBJECTIVE

To report the outcomes of a posterior hybrid decompression protocol for the treatment of cervical spondylotic myelopathy (CSM) associated with hypertrophic ligamentum flavum (HLF).

BACKGROUND

Laminoplasty is widely used in patients with CSM; however, for CSM patients with HLF, traditional laminoplasty does not include resection of a pathological ligamentum flavum.

METHODS

This study retrospectively reviewed 116 CSM patients with HLF who underwent hybrid decompression with a minimum of 12 months of follow-up. The procedure consisted of reconstruction of the C4 and C6 laminae using CENTERPIECE plates with spinous process autografts, and resection of the C3, C5, and C7 laminae. Surgical outcomes were assessed using Japanese Orthopedic Association (JOA) score, recovery rate, cervical lordotic angle, cervical range of motion, spinal canal sagittal diameter, bone healing rates on both the hinge and open sides, dural sac expansion at the level of maximum compression, drift-back distance of the spinal cord, and postoperative neck pain assessed by visual analog scale.

RESULTS

No hardware failure or restenosis was noted. Postoperative JOA score improved significantly, with a mean recovery rate of 65.3 ± 15.5%. Mean cervical lordotic angle had decreased 4.9 degrees by 1 year after surgery (P<0.05). Preservation of cervical range of motion was satisfactory postoperatively. Bone healing rates 6 months after surgery were 100% on the hinge side and 92.2% on the open side. Satisfactory decompression was demonstrated by a significantly increased sagittal canal diameter and cross-sectional area of the dural sac together with a significant drift-back distance of the spinal cord. The dural sac was also adequately expanded at the time of the final follow-up visit.

CONCLUSION

Hybrid laminectomy and autograft laminoplasty decompression using Centerpiece plates may facilitate bone healing and produce a comparatively satisfactory prognosis for CSM patients with HLF.

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.

Impact of diabetes on the outcomes of cervical laminoplasty: a prospective cohort study of more than 500 patients with cervical spondylotic myelopathy

STUDY DESIGN

A prospective cohort study.

OBJECTIVE

This study aimed to compare the outcome of cervical laminoplasty between diabetic patients and nondiabetic patients with cervical spondylotic myelopathy.

SUMMARY OF BACKGROUND DATA

A few retrospective studies have investigated the outcomes of cervical myelopathy in diabetic patients; therefore, our large-scale cohort study was designed to assess these outcomes in cervical spondylotic myelopathy.

METHODS

In total, 505 consecutive patients with cervical spondylotic myelopathy (311 males, 194 females; mean age, 66.6 yr; range, 41-91 yr) who underwent double-door laminoplasty were prospectively enrolled. They were followed up for more than 12 months after surgery (mean follow-up period, 25.6 ± 12.6 mo). The patients were divided on the basis of diabetic criteria for glucose intolerance into 2 groups: the diabetic group (n = 105) and nondiabetic group (n = 400). We evaluated differences in pre- and postoperative Japanese Orthopaedic Association (JOA) scores, recovery rate, achieved JOA scores (postoperative JOA score - preoperative JOA score), and complications between both groups.

RESULTS

The mean JOA scores in the diabetic and nondiabetic groups were 10.1 and 10.8 points before surgery and 13.1 and 13.9 points after surgery, respectively. The diabetic group showed significantly low pre- and postoperative JOA scores and low recovery rate of JOA scores compared with the nondiabetic group (47.3% vs. 53.6%, P < 0.05). However, mean achieved JOA scores in the diabetic and nondiabetic groups were 3.0 and 3.1 points respectively, with no significant difference between both groups (P = 0.343). The groups showed no significant difference in the postoperative complication rate.

CONCLUSION

Pre- and postoperative JOA scores and recovery rates were lower in the diabetic group than the nondiabetic group. However, the achieved JOA scores were not significantly different between both groups. Diabetic and nondiabetic patients experienced similar benefits from laminoplasty.

LEVEL OF EVIDENCE

3.

Laminoplasty versus skip laminectomy for the treatment of multilevel cervical spondylotic myelopathy: a systematic review

INTRODUCTION

Laminoplasty and skip laminectomy are two specific posterior surgical approaches for multilevel cervical spondylotic myelopathy. The objective of this study was to perform a systematic review comparing the clinical results and complications of laminoplasty and skip laminectomy in the treatment of multilevel cervical spondylotic myelopathy.

MATERIALS AND METHODS

We reviewed and analyzed papers published from January 1969 to December 2012 through the Mediline, Embase, Cochrane review library, and other databases regarding the comparison between laminoplasty and skip laminectomy for multilevel cervical spondylotic myelopathy.

RESULTS

One randomized controlled trial and three non-randomized controlled trials were included in this systematic review. In three studies, the preoperative and postoperative JOA score was similar in both laminoplasty and skip laminectomy groups. In addition, for recovery rate, there was no significant difference between the groups. One study reported that, regarding SF12 scores, there was no significant difference in physical health and mental health after surgery. However, regarding cervical pain, the skip laminectomy group was better than the laminoplasty group significantly. No difference was presented in postoperative ROM and the cervical lordosis between the groups. But the ROM % (post/pre) was reported to be significantly better in the skip laminectomy group in three studies. Less blood loss and shorter operation time were observed in skip laminectomy rather than laminoplasty.

CONCLUSIONS

Based on the results above, the skip laminectomy group presented better outcomes in a variety of aspects: ROM % (post/pre), complication rate, surgical trauma, etc. However, as limited study samples were included in the paper, a claim of superiority of the two approaches could not be justified. Further studies are required on the comparison between laminoplasty and skip laminectomy.

Effect of type II odontoid fracture nonunion on outcome among elderly patients treated without surgery: based on the AOSpine North America geriatric odontoid fracture study

STUDY DESIGN

Subgroup analysis of a prospective multicenter study.

OBJECTIVE

Outcome analysis of nonoperatively treated elderly patients with type II odontoid fractures, including assessment of consequence of a fracture nonunion.

SUMMARY OF BACKGROUND DATA

Odontoid fractures are among the most common fractures in the elderly, and controversy exists regarding treatment.

METHODS

Subgroup analysis of a prospective multicenter study of elderly patients (≥65 yr) with type II odontoid fracture. Neck Disability Index and Short-Form 36 (SF-36) version 2 were collected at baseline and 6 and 12 months. Fifty-eight (36.5%) of the 159 patients were treated nonoperatively.

RESULTS

Of the 58 patients initially treated nonoperatively, 8 died within 90 days and were excluded. Of the remaining 50 patients, 11 (22.0%) developed nonunion, with 7 (63.6%) requiring surgery. Four of the 39 (10.3%) patients classified as having "successful union" required surgery due to late fracture displacement. Thus, 15 (30.0%) patients developed primary or secondary nonunion and 11 (22.0%) required surgery. The overall 12-month mortality was 14.0% (nonunion = 2, union = 5; P= 0.6407). For union and nonunion groups, Neck Disability Index and SF-36 version 2 declined significantly at 12 months compared with preinjury values (P< 0.05), except for SF-36 version 2 Physical Functioning (P= 0.1370). There were no significant differences in outcome parameters based on union status at 12 months (P> 0.05); however, it is important to emphasize that the 12-month outcomes for the nonunion patients reflect the status of the patient after delayed surgical treatment in the majority of these cases.

CONCLUSION

Nonoperative treatment for type II odontoid fracture in the elderly has high rates of nonunion and mortality. Patients with nonunion did not report worse outcomes compared with those who achieved union at 12 months; however, the majority of patients with nonunion required delayed surgical treatment. These findings may prove useful for patients who are not surgical candidates or elect for nonoperative treatment.

LEVEL OF EVIDENCE

2.

Laminoplasty versus laminectomy for multi-level cervical spondylotic myelopathy: a systematic review of the literature

Background

There is considerable controversy as to which posterior technique is best for the treatment of multi-level cervical spondylotic myelopathy. The aim of this study was to compare the clinical and radiographic results and complications of laminoplasty (LAMP) and laminectomy (LAMT) in the treatment of multi-level cervical spondylotic myelopathy.

Methods

We reviewed and analyzed papers published from January 1966 and June 2013 regarding the comparison of LAMP and LAMT for multi-level cervical spondylotic myelopathy. Statistical comparisons were made when appropriate.

Results

Fifteen studies were included in this systematic review. There was no significant difference in the incidence of surgical complications between LAMP and LAMT. Compared to conventional LAMT and skip LAMT, postoperative ROM was more limited in LAMP, but this was still superior to postoperative ROM following LAMT with fusion. Postoperative kyphosis occurred in 8/180 (4.44%) in LAMP and 13/205 (6.34%) in LAMT, whereas no cases of kyphosis were reported for skip LAMT. Skip LAMT appears to have better clinical outcomes than LAMP, while the outcome was similar between LAMP and LAMT with fusion.

Conclusions

Based on these results, a claim of superiority for laminoplasty or laminectomy was not justified. In deciding between the two procedures, the risks of surgical and neurological complications, and radiologic and clinical outcome, must be taken into consideration if both options are available in multi-level cervical spondylotic myelopathy.

Modified double-door laminoplasty in managing multilevel cervical spondylotic myelopathy: surgical outcome in 520 patients and technique description

STUDY DESIGN

This is a prospective study on surgical outcomes of double-door laminoplasty in patients with cervical spondylotic myelopathy (CSM).

OBJECTIVE

The purpose of this study was to report the efficacy and safety of modified double-door laminoplasty in a large series of patients with CSM.

SUMMARY OF BACKGROUND DATA

Laminoplasty is an established procedure for the decompression of multisegmental CSM. However, no report has described the clinical outcomes of laminoplasty for a large number of patients with CSM (>500 patients).

METHODS

Between April 1995 and December 2006, 520 consecutive patients (331 male and 189 female) with CSM who underwent double-door laminoplasty and were followed-up for more than 1 year were enrolled in this study. The mean age was 62.2 years (23 to 93 y), and the mean duration of disease was 20.1 ± 32.0 months. The severity of myelopathy before and after surgery was evaluated according to a scoring system proposed by the Japanese Orthopedic Association for cervical myelopathy (JOA score). Functional improvement was expressed by the recovery rate (RR) of the JOA score.

RESULTS

The average surgery time for laminoplasty was 75.2 ± 23.3 minutes, and the average blood loss was 72.6 ± 84.6 mL. The average follow-up period was 33.3 ± 15.7 months. The mean JOA score was 10.4 ± 2.8 points preoperatively and 13.6 ± 2.5 points at final follow-up. The mean RR was 51.2 ± 2 9.0%. On the basis of RR, we found that the conditions of 493 patients (94.8%) improved (RR, >1%), 20 patients (3.8%) showed no change (RR, 0%), and 7 patients (1.3%) in worse condition (RR, < 0%). The 7 patients deteriorated for reasons (lumbar spinal canal stenosis and cerebral infarction) that were unrelated to CSM.

CONCLUSIONS

Modified double-door laminoplasty is a safe, reliable, and effective procedure for patients with CSM.

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.

A less-invasive cervical laminoplasty for spondylotic myelopathy that preserves the semispinalis cervicis muscles and nuchal ligament

Object

Modified cervical laminoplasty techniques have been developed to reduce postoperative axial neck pain and preserve function in patients with cervical spondylotic myelopathy (CSM). However, the previous studies demonstrating satisfactory surgical outcomes had a retrospective design. Here, the authors aimed to prospectively evaluate the 2-year outcomes of a modified cervical laminoplasty technique for CSM that preserves the paravertebral muscles.

Methods

Outcomes were analyzed for 40 patients (22 men and 18 women; mean age, 66.6 years; age range 44–92 years) with CSM who underwent C4–6 laminoplasty with C-3 and C-7 partial laminectomies or C-3 total and C-7 partial laminectomies and received hydroxyapatite spacers. Neurological, pain severity, and spinal radiographic evaluations were performed preoperatively and at 3, 6, 12, 18, and 24 months postoperatively. Plain radiography and MRI of the cervical spine were performed to evaluate the range of motion (ROM), sagittal alignment, and cross-sectional areas of the deep extensor muscles. The extent of bone–spacer bonding and bony union at the gutter was assessed by CT.

Results

The mean preoperative Japanese Orthopaedic Association CSM score was 10.2, but it increased to 14.4 by 24 months after surgery. Eleven patients had axial neck pain preoperatively, but only 3 reported mild pain at 24 months, and in all 3 cases the pain was mild. The mean angle of lordosis was 11.7° preoperatively and 12.0° 2 years postoperatively. Although the ROM at the C2–7 levels was significantly reduced 3 months postoperatively, an increasing trend was observed up to 12 months, and 86% of the preoperative ROM was achieved by 2 years postoperatively. The mean paravertebral muscle cross-sectional areas were 833 ± 215 mm2 preoperatively and 763 ± 197 mm2 24 months postoperatively, but the difference was not statistically significant. The rates of bone–spacer bonding and bony union at the gutter were low during the early stages but increased to 90% and 93%, respectively, by 2 years after surgery.

Conclusions

The modified laminoplasty technique used in this study ensured very good neurological status and ROM after 2 years and was associated with low incidences of axial neck pain and serious complications. This simple and easy operative method could benefit future laminoplasty protocols.

Laminoplasty and laminectomy for cervical sponydylotic myelopathy: a systematic review

BACKGROUND

Cervical spondylotic myelopathy is frequently encountered in neurosurgical practice. The posterior surgical approach includes laminectomy and laminoplasty.

OBJECTIVE

To perform a systematic review evaluating the effectiveness of posterior laminectomy compared with posterior laminoplasty for patients with cervical spondylotic myelopathy.

METHODS

An extensive search of the literature in Pubmed, Embase, and Cochrane library was performed by an experienced librarian. Risk of bias was assessed by two authors independently. The quality of the studies was graded, and the following outcome measures were retrieved: pre- and postoperative (m)JOA, pre- and postoperative ROM, postoperative VAS neck pain, and Ishira cervical curvature index. If possible data were pooled, otherwise a weighted mean was calculated for each study and a range mentioned.

RESULTS

All studies were of very low quality. Due to inadequate description of the data in most articles, pooling of the data was not possible. Qualitative interpretation of the data learned that there were no clinically important differences, except for the higher rate of procedure-related complications with laminoplasty.

CONCLUSION

Based on these results, a claim of superiority for laminoplasty or laminectomy was not justified. The higher number of procedure-related complications should be considered when laminoplasty is offered to a patient as a treatment option. A study of robust methodological design is warranted to provide objective data on the clinical effectiveness of both procedures.

Localization of the medial branches of the cervical dorsal rami during cervical laminoplasty

STUDY DESIGN

Observational anatomic study.

OBJECTIVE

To give precise information on the surgical anatomy of the medial branches of the cervical dorsal rami.

SUMMARY OF BACKGROUND DATA

The anatomy of the medial branches has not been sufficiently described.

METHODS

We recorded the location of the medial branches in 94 consecutive patients who underwent laminoplasty for cervical compression myelopathy. A posterior cervical approach was made along the edge of the nuchal ligament, and, after carefully detaching the trapezius muscle from the nuchal ligament; we identified the right-side branches around the semispinalis capitis muscle. We recorded the location of the branches with reference to the spinous processes and the semispinalis capitis and trapezius muscles. In 52 patients, we electrically stimulated the branches and observed the contraction of these muscles.

RESULTS

Branches were identified between C3 and C6 spinous process levels in 92 patients. A single branch was identified in 56 patients, 2 branches were identified in 35 patients, and 3 branches were identified in the remaining 1 patient. Branches were located between C3 and C4 (n = 12), between C4 and C5 (n = 80), between C5 and C6 (n = 2), and at C6 (n = 35). There were 4 patterns of final course: 52 branches passed through the medial side of the semispinalis capitis and trapezius muscles and terminated in a subcutaneous area; 50 branches penetrated the semispinalis capitis and trapezius muscles and terminated in a subcutaneous area; 12 branches terminated in the semispinalis capitis muscle; and 15 branches penetrated the semispinalis capitis and terminated at the nuchal ligament. In 19 of 52 patients tested, the semispinalis capitis muscle contracted after electrical stimulation.

CONCLUSION

Medial branches of the cervical dorsal rami were discernible in cervical posterior approach laminoplasty and were frequently found adjacent to C4 and C5 spinous processes. The medial branches sometimes supplied motor fibers to the semispinalis capitis muscle. Knowledge of the course of these branches might be helpful for avoiding injury during laminoplasty.

Radiographical risk factors for major intraoperative blood loss during laminoplasty in patients with ossification of the posterior longitudinal ligament

STUDY DESIGN

A retrospective multi-institutional study.

OBJECTIVE

To clarify the distribution of intraoperative blood loss during cervical laminoplasty for ossification of the posterior longitudinal ligament (OPLL), and to identify the radiographical risk factors for the occurrence of major blood loss in patients with OPLL undergoing laminoplasty.

SUMMARY OF BACKGROUND DATA

The incidence of major intraoperative blood loss during laminoplasty for OPLL is unknown.

METHODS

All patients who underwent cervical laminoplasty for OPLL between April 2005 and March 2008 at 27 institutions across Japan were included in this analysis. We investigated the patients' characteristics and surgical data, and compared the radiographical characteristics of OPLL in patients with and without major blood loss.

RESULTS

The estimated intraoperative blood loss was reported for 545 patients (429 male and 116 female; mean age, 62.7 yr). The mean intraoperative blood loss was 223 g (median, 130 g; range, minimal to 3350 g). Excluding 1 patient with intraoperative vertebral artery injury, major blood loss greater than 500 g was reported in 45 patients (8.3%). Patients with major blood loss were more likely to have neurological complications (5/45 vs. 12/499) and a longer hospital stay (29.5 d vs. 28.8 d) in comparison with those without major blood loss. The occupying ratio of OPLL was greater in the major blood loss group (48.3% vs. 42.2%; P = 0.02). A multivariate analysis revealed an occupying ratio of 60% or greater to be associated with an increased risk of major intraoperative blood loss (odds ratio, 2.4; 95% confidence interval, 1.1-5.3).

CONCLUSION

Laminoplasty for OPLL is associated with a risk of major intraoperative blood loss, which can potentially give rise to devastating postoperative complications. An occupying ratio of 60% or greater is a risk factor for major blood loss during laminoplasty in patients with OPLL.

Cervical laminectomy vs laminoplasty: is there a difference in outcome and postoperative pain?

BACKGROUND

Cervical laminoplasty is often used for the decompression of multilevel cervical spondylotic myelopathy without creating spinal instability and kyphosis.

OBJECTIVE

To assess the axial pain, quality of life, sagittal alignment, and extent of decompression after standard cervical laminectomy or laminoplasty. We further evaluate whether the sagittal alignment changes over time after both procedures and whether axial pain depends on sagittal alignment.

METHODS

We reviewed 268 patients with cervical radiculopathy or myelopathy who had undergone standard cervical laminectomy or laminoplasty between January 1999 and January 2009. The clinical outcome was analyzed by visual analog scale for neck pain. The quality of life was analyzed by EQ-5D questionnaire. The degree of deformity and extent of decompression were assessed using the Ishihara index and Pavlov's ratio, respectively.

RESULTS

Laminoplasty was associated with more neck pain and worse quality of life when 4 or more levels were decompressed compared with the laminectomy group. For operations of 3 or fewer levels, there was no difference. Interestingly, the radiological effectiveness of decompression was greater in the laminoplasty group.

CONCLUSION

Laminoplasty for 4 or more cervical levels was associated with more axial pain and consequently poorer quality of life than laminectomy. There was a similar loss of sagittal alignment in both the laminectomy and laminoplasty groups over time. Our results suggest there is no clear benefit of laminoplasty over laminectomy in patients who do not have spinal instability.

The prevalence of pre- and postoperative symptoms in patients with cervical spondylotic myelopathy treated by cervical laminoplasty

STUDY DESIGN

A retrospective single-center study.

OBJECTIVE

To investigate the prevalence of symptoms before and after surgery in a large series of patients with cervical spondylotic myelopathy (CSM).

SUMMARY OF BACKGROUND DATA

No study has elucidated the epidemiological data regarding the prevalence of pre- and postoperative symptoms in patients with CSM.

METHODS

Five hundred twenty consecutive patients with CSM (331 male and 189 female; mean age, 62.2 yr) treated by laminoplasty were enrolled. The average follow-up period was 33.3 months. Severity of myelopathy was evaluated according to a scoring system proposed by the Japanese Orthopedic Association for CSM, and prevalence was determined by the presence or absence of a full Japanese Orthopedic Association score for each function. The persistence rate (%) (postoperative prevalence/preoperative prevalence × 100) of each function impairment was also assessed after surgery.

RESULTS

The preoperative prevalence of motor function impairment in the upper and lower extremities was 77.7% and 80.4%, respectively, whereas that of sensory function impairment in the upper and lower extremities and trunk was 88.6%, 56.5%, and 48.3%, respectively. The preoperative prevalence of urinary bladder function impairment was 41.2%. The persistence rate of motor function impairment in the upper and lower extremities was 52.7% and 71.5%, respectively, whereas that of sensory function impairment in the upper and lower extremities and trunk was 72.0%, 56.8%, and 61.4%, respectively. The persistence rate of urinary bladder function impairment was 49.1%.

CONCLUSION

The preoperative prevalence of motor function impairment in the upper and lower extremities and that of sensory function impairment in the upper extremity is higher than that of other function impairments, and impairments in lower extremity motor function and upper extremity sensory function often persist after surgery. These findings provide baseline data that may allow clinicians to accurately assess preoperative impairment and postoperative outcomes in patients with CSM.

Cervical alignment and range of motion after laminoplasty: radiographical data from more than 500 cases with cervical spondylotic myelopathy and a review of the literature

STUDY DESIGN

A large-scale analysis of radiographical results of patients with cervical spondylotic myelopathy and a review of the literature.

OBJECTIVE

To identify changes in sagittal alignment and range of motion (ROM) after cervical laminoplasty.

SUMMARY OF BACKGROUND DATA

Cervical laminoplasty is an effective procedure for decompressing multilevel spinal cord compression. It often induces postoperative complications such as loss of lordotic alignment and restriction of neck motion. Although numerous studies have reported the loss of flexion-extension ROM after laminoplasty, no large-scale study has been reported.

METHODS

Five hundred twenty consecutive patients with cervical spondylotic myelopathy (331 male and 189 female; mean age, 62.2 yr) who underwent modified double-door laminoplasty were enrolled. The average follow-up period was 33.3 months. All patients were allowed to sit up and walk on the first postoperative day using an orthosis, which could be removed within the first 2 weeks, even if long. Early cervical ROM exercises were performed as a part of the rehabilitation schedule. Radiography was performed before surgery and at the final follow-up. Cervical alignment in the neutral and flexion-extension view were measured by the Cobb method at C2-C7. The ROM was assessed by measuring the difference in alignment between flexion and extension.

RESULTS

The mean C2-C7 alignment in the neutral position was 11.9° lordotic preoperatively and 13.6° lordotic postoperatively; the alignment increased by 1.8° in lordosis. The mean total ROM decreased from a preoperative value of 40.1° to 33.5° at the final follow-up, showing a significant difference of 6.6°. The mean total ROM preservation after laminoplasty was 87.9%.

CONCLUSION

Sagittal alignment was slightly changed, with only a 1.8° increase in lordosis. The ROM of the cervical spine was preserved by 87.9%. This preservation of alignment and ROM might be attributable to improvements including early removal of the cervical orthosis, postoperative neck exercises, and some surgical modifications.

Morphological features and clinical significance of epidural membrane in the cervical spine

STUDY DESIGN

A prospective clinical study.

OBJECTIVE

To elucidate the histomorphological features and clinical significance of the epidural membrane (EM) in the cervical spine based on operative and histological findings.

SUMMARY OF BACKGROUND DATA

The anatomical features of the EM have been mostly discussed on the basis of cadaver studies in the whole spine. However, the histomorphological features and clinical significance of the EM in the cervical spine based on operative findings have never been reported.

METHODS

Eighty-seven patients with cervical spondylotic myelopathy who had undergone an expansive open-door laminoplasty under microscopy were evaluated with a more than 2-year follow-up period. The most damaged spinal segment was determined in each patient from the preoperative neurological and image findings along with the remaining symptoms at follow-up. The morphological features of the EM were observed and recorded in each patient during decompression. For histology, specimens of common and remarkable types of the EM obtained from 16 patients were examined.

RESULTS

The age at surgery averaged 64.5 years; there were 58 men and 29 women. With regard to the most damaged spinal segment, there were 14 cases at the C3-C4 level, 37 at the C4-C5 level, 32 at the C5-C6 level, and 4 at the C6-C7 level. The EM was an adipo-fibro-vascular tissue with various histomorphologies, blending with the periradicular sheath. Some EMs showed notable findings: obstructing dural tube expansion (13 cases, 14.9%), compressing a nerve root or disturbing its mobility (4 cases, 4.6%), and the combined type (1 case, 1.1%). All of them were located at approximately the most damaged spinal segment. In addition, some EMs had interesting histological features, such as harboring many small arteries, calcified debris, and metaplastic bone fragments.

CONCLUSION

The EM can develop into remarkable structures with spondylosis and aging in patients with cervical spondylotic myelopathy, affecting surgical outcomes as well as successful decompression procedures. A sound understanding of the histomorphological features of the EM is required to obtain satisfactory surgical outcomes in the limited field afforded by minimally invasive surgery.

Persistent physical symptoms after laminoplasty: analysis of postoperative residual symptoms in 520 patients with cervical spondylotic myelopathy

STUDY DESIGN

A large-scale retrospective study of analysis of postoperative residual symptom in patients with cervical spondylotic myelopathy (CSM).

OBJECTIVE

The purpose of this study was to investigate which symptom remains postoperatively in a large series of patients with CSM.

SUMMARY OF BACKGROUND DATA

CSM is an increasingly common neurological disorder of the geriatric population. Cervical laminoplasty is an established procedure for the decompression of multisegmental CSM, and numerous studies have documented satisfactory surgical results. However, no report has yet elucidated the postoperative residual symptoms in patients with CSM.

METHODS

Between April 1995 and December 2006, 520 consecutive patients with CSM who underwent laminoplasty were enrolled in this study. They were 331 males and 189 females, and mean age was 62.2 years. Severity of myelopathy was evaluated according to a scoring system proposed by the Japanese Orthopedic Association for cervical myelopathy. Each functional improvement was expressed by the recovery rate (RR) of the Japanese Orthopedic Association score.

RESULTS

The average follow-up period was 33.3 months. The mean recovery rates of motor function of the upper and lower extremities were 59.6% and 44.9%, respectively. The mean recovery rates of sensory function of the upper extremity, lower extremity, and trunk were 48.1%, 56.6%, and 54.6%, respectively, and that of urinary bladder function was 59.6%.

CONCLUSION

Motor function impairments of the lower extremities and sensory function impairments of the upper extremities persist more than other symptoms after surgery. Such findings should be incorporated within treatment-planning discussions.

Can elderly patients recover adequately after laminoplasty?: a comparative study of 520 patients with cervical spondylotic myelopathy

STUDY DESIGN

This was a prospective clinical comparative study of surgical outcomes for patients with cervical spondylotic myelopathy (CSM).

OBJECTIVE

The purpose of this study was to compare the surgical outcomes between nonelderly and elderly patients with CSM who underwent laminoplasty.

SUMMARY OF BACKGROUND DATA

Age at the time of surgery influences the surgical outcome. We designed a large-scale study of the surgical outcome for CSM from a single operative procedure used exclusively in elderly patients.

METHODS

A total of 520 consecutive patients with CSM (331 men; 189 women) who underwent double-door laminoplasty were included. Mean age was 62 years (range, 23-93), and mean duration of disease was 20.1 ± 32.0 months. Average postoperative follow-up period was 33.3 ± 15.7 months. Patients were divided into 3 groups by age: nonelderly (<65 years), young-old (65-74 years), and old-old (≥75 years). The number of patients in each group was 287, 143, and 90. Pre- and postoperative neurological status was evaluated using the Japanese Orthopaedic Association scoring system for cervical myelopathy (JOA score).

RESULTS

Mean pre- and postoperative JOA scores in nonelderly, young-old, and old-old groups were 11.0 and 14.4, 10.2 and 13.2, and 8.7 and 11.8 points, respectively. The elderly group showed significantly low recovery rates of JOA scores compared with the nonelderly group (P < 0.0001). However, mean achieved JOA scores (postoperative JOA score - preoperative JOA score) were 3.4, 3.0, and 3.1 in nonelderly, young-old, and old-old groups, respectively, with no significant difference among these groups (P = 0.17).

CONCLUSION

Pre- and postoperative JOA scores were low in elderly patients. However, the achieved JOA score was almost similar among the 3 groups. Thus, elderly patients could obtain reasonable recovery after cervical laminoplasty.

Impact of deep extensor muscle-preserving approach on clinical outcome of laminoplasty for cervical spondylotic myelopathy: comparative cohort study

INTRODUCTION

This study aimed to compare patients undergoing deep extensor muscle-preserving laminoplasty and conventional open-door laminoplasty for the treatment of cervical spondylotic myelopathy (CSM). We specifically assessed axial pain, cervical spine function, and quality of life (QOL) with a minimum follow-up period of 3 years.

PATIENTS AND METHODS

Ninety patients were divided into two groups and underwent either conventional open-door laminoplasty (CL group) or laminoplasty using the deep extensor muscle-preserving approach (MP group). The latter approach was undertaken by preserving the multifidus and semispinalis cervicis attachments followed by open-door laminoplasty and resuturing of the bisected spinous processes at each decompression level. The mean follow-up period was 7.7 years (range, 36-128 months). Preoperative and follow-up evaluations included the Japanese Orthopaedic Association (JOA) score, a tentative version of the JOA Cervical Myelopathy Evaluation Questionnaire (JOACMEQ) including cervical spine function and QOL, and a visual analog scale (VAS) for axial pain. Radiological analyses included cervical lordosis and flexion-extension range of motion (C2-7), as well as deep extensor muscle areas on axial magnetic resonance imaging (MRI).

RESULTS

The mean number of decompressed laminae was 3.9 and 3.3 in CL and MP groups, respectively, which was statistically equivalent. Japanese Orthopaedic Association recovery was statistically equivalent between the two groups. The MP group demonstrated a superior QOL score (57 vs. 46%) compared with the CL group at final follow-up (p < 0.05). Mean VAS scores at final follow-up were 2.2 and 4.3 in MP and CL groups, respectively (p < 0.05). Cervical lordosis and flexion-extension range of motion were statistically equivalent. The percentage deep muscle area on MRI was significantly lesser in the CL group compared with the MP group (58 vs. 102%; p < 0.01).

CONCLUSION

We demonstrated the superiority of deep extensor muscle-preserving laminoplasty in terms of postoperative axial pain, QOL, and prevention of atrophy of the deep extensor muscles over conventional open-door laminoplasty for the treatment of CSM.

Posterior surgery for cervical myelopathy: indications, techniques, and outcomes

This article details the controversies associated with the different treatment strategies in patients with cervical spondylotic myelopathy. The natural history, incidence, pathophysiology, physical examination, and imaging findings are discussed followed by the indications, techniques, and outcomes of patients treated with posterior cervical decompression via decompressive laminectomy, laminectomy and instrumented fusion, and laminoplasty.

Laminotomy in adults: technique and results

The objective of this study was to describe step by step our surgical technique of laminotomy and analyze our series with regard to spinal deformities (risk and predisposing factors), postoperative pain and rate of postoperative contusions. Data regarding patients who underwent our technique of laminotomy (N = 40, mean follow-up: 52 ms) (N = 40) between 2002 and 2006 were retrospectively evaluated. The technique used is illustrated in depth. Chronic pain was present in 30% with a mean score of 3/10 cm (Graphic Rating Scale). Postoperative kyphoses occurred in three patients, all below 35 years of age and with laminotomies which involved C2 and/or C7. None of these deformities required further surgical treatment because they were self-limiting or asymptomatic at a mean follow-up of 52 months. Based on the results, our technique proved to be safe and effective in terms of late deformities, blood loss, early and chronic postoperative pain and protection from postoperative accidents over the surgical site.

Preserving the C7 spinous process in laminectomy combined with lateral mass screw to prevent axial symptom

BACKGROUND

Preserving the C7 spinous process during cervical laminoplasty has been reported to prevent axial symptom. Some patients underwent laminectomy and fixation developed the symptom. The objective of this article was to investigate whether axial symptom can be reduced by preserving the C7 spinous process during cervical laminectomy and fixation with lateral mass screw.

METHODS

Between 2005 and 2008, data of 53 patients who underwent laminectomy and lateral mass-screw fixation for multilevel cervical myelopathy were reviewed. Analysis consisted of the incidence of axial symptom, Japan Orthopaedic Association (JOA) scores, recovery rate, cervical lordotic angle, and atrophy rate of cervical posterior muscle. Axial symptom severity was quantified by a visual analog scale (VAS). Twenty-five patients were decompressed from C3 to C7 (group A) and 28 from C3 to C6 with dome-shape removal of the C7 superior lamina (group B).

RESULTS

Analysis of final follow-up data showed improvement in clinical outcome for both groups. No difference in recovery rate, cervical lordotic angle and atrophy rate was observed between groups. Postoperative axial-neck pain was significantly rarer in group B than in group A. Axial symptom severity was correlated with cervical posterior muscle atrophy rate; correlation coefficient was 0.665.

CONCLUSION

The C7 spinous process might play an important role in preventing axial symptom, but there is a need for randomized, control studies with long-term follow-up to clarify the results.

Is decompressive surgery effective for spinal cord sarcoidosis accompanied with compressive cervical myelopathy?

STUDY DESIGN

A retrospective multicenter study of series of 12 patients with spinal cord sarcoidosis who underwent surgery.

OBJECTIVE

To evaluate the postoperative outcomes of patients with cervical spinal cord sarcoidosis accompanied with compressive myelopathy and effect of decompressive surgery on the prognosis of sarcoidosis.

SUMMARY OF BACKGROUND DATA

Sarcoidosis is a chronic, multisystem noncaseating granulomatous disease. It is difficult to differentiate spinal cord sarcoidosis from cervical compressive myelopathy. There are no studies regarding the coexistence of compressive cervical myelopathy with cervical spinal cord sarcoidosis and the effect of decompressive surgery.

METHODS

Nagoya Spine Group database included 1560 cases with cervical myelopathy treated with cervical laminectomy or laminoplasty from 2001 to 2005. A total of 12 patients (0.08% of cervical myelopathy) were identified spinal cord sarcoidosis treated with decompressive surgery. As a control subject, 8 patients with spinal cord sarcoidosis without compressive lesion who underwent high-dose steroid therapy without surgery were recruited.

RESULTS

In the surgery group, enhancing lesions on magnetic resonance imaging (MRI) were mostly seen at C5-C6, coincident with the maximum compression level in all cases. Postoperative recovery rates in the surgery group at 1 week and 4 weeks were -7.4% and -1.1%, respectively. Only 5 cases had showed clinical improvement, and the condition of these 5 patients had worsened again at averaged 7.4 weeks after surgery. Postoperative oral steroid therapy was initiated at an average of 6.4 weeks and the average initial dose was 54.0 mg in the surgery group, while 51.3 mg in the nonsurgery group. The recovery rate of the Japanese Orthopedic Association score, which increased after steroid therapy, was better in the nonsurgery group (62.5%) than in the surgery group (18.6%) with significant difference (P < 0.01).

CONCLUSION

The effect of decompression for spinal cord sarcoidosis with compressive myelopathy was not evident. Early diagnosis for sarcoidosis from other organ and steroid therapy should be needed.

Axial pain after posterior cervical spine surgery: a systematic review

Posterior operative approach has been the standard treatment for cervical compressive myelopathy, and axial pain after laminoplasty or laminectomy as a postoperative complication is now gradually receiving more and more attention. The objective of this study was to provide a systematic review of the current understanding of axial pain after cervical laminoplasty and laminectomy, and summarize clinical features, influence factors and preventive measures of axial pain after posterior decompressive surgery based on a review of literature published in the English language. Axial pain distributes over nuchal, periscapular and shoulder regions. Posterior surgery is not the major cause of axial pain, but axial pain can be worsened by the procedure. There are many clinical factors that influence postoperative axial pain such as age, preoperative axial pain, different surgical technique and postoperative management, but most of them are still controversial. Several surgical modifications have been innovated to reduce axial pain. Less invasive surgery, reconstruction of the extensor musculature, avoiding detachment of the semispinalis cervicis muscle and early removal of external immobilization have proved to be effective. Axial pain is under the influence of multiple factors, so comprehensive methods are required to reduce and avoid the postoperative axial pain. Because of methodological shortcomings in publications included in this systematic review, different results from different studies may be produced due to differences in study design, evaluation criteria, sample size, and incidence or severity of axial pain. More high-quality studies are necessary for drawing more reliable and convincing conclusions.

Neck muscle strength before and after cervical laminoplasty: relation to axial symptoms

STUDY DESIGN

A prospective study to investigate serial changes in neck muscle strength before and after cervical laminoplasty.

OBJECTIVES

To examine the correlation between neck muscle strength and axial symptoms, and to clarify the risk factors for axial symptoms.

SUMMARY OF BACKGROUND DATA

Axial symptoms are common complications after posterior cervical spinal surgery. Although several technical considerations have reduced axial symptoms, the causes of axial symptoms are still largely unknown. Previous studies have indicated that neck muscle strength is reduced in patients with neck pain.

MATERIALS AND METHODS

Nineteen consecutive patients underwent cervical expansive laminoplasty for cervical spondylotic myelopathy. Age, sex, operative time, blood loss, clinical results, cervical curvature, range of motion, visual analog scale (VAS) for axial symptoms, and manual muscle strengths were examined before and after surgery. At 3 and 12 months, these factors were compared statistically between the no pain (NP) group (VAS <3) and the pain (P) group (VAS >or=3). The correlation between VAS and neck muscle strength, and the reduction in neck muscle strength in extension were analyzed statistically.

RESULTS

Six patients (31.5%) complained of axial symptoms at 3 months, and the symptoms continued in 3 patients (15.8%) at 12 months. At 3 months, cervical lordosis was 15.7 degrees in the NP group and 5.0 degrees in the P group, and neck strength in extension was 104.9% and 61.8%, respectively. At 12 months, neck strength in extension was 124.3% and 62.2%, respectively. These differences were statistically significant. The correlation between neck pain VAS and neck muscle strength, and the reduction in neck muscle strength in extension were statistically significant.

CONCLUSIONS

Neck muscle strength recovered to the preoperative value by 3 months and increased to 120% by 12 months in the NP group, whereas in the P group, neck muscle strength remained reduced by 60% and did not recover. Neck muscle strength and axial symptoms were strongly correlated.

Decompressive laminoplasty in multisegmental cervical spondylotic myelopathy: bilateral cutting versus open-door technique

PURPOSE

The aim of the study was to evaluate patients with multisegmental cervical spondylotic myelopathy (MCM) surgically treated via a dorsal approach. Two different laminoplasty techniques were compared by assessment of enlargement of the spinal canal and the neurological outcome.

METHODS

Thirteen patients (mean age 49 years, 11 males) underwent decompressive laminoplasty over a 7-year period. The average duration of symptoms was 21 months. The pre- and postoperative degree of myelopathy was assessed by both the Nurick grading and the Japanese Orthopaedic Association myelopathy score (JOA score). Preoperatively, the mean Nurick grade was 3.1 and the mean JOA score was 11. Two different techniques of expansive laminoplasty were used. Six patients underwent a bilateral cutting (BL) technique with retropositioning of the laminae and bilateral mini-plating (BL group). Seven patients were operated on by simple open-door (OD) laminoplasty with unilateral mini-plating (OD group). Postoperatively, CT scans were obtained for all patients to measure the sagittal diameter of the spinal canal. The mean clinical and radiological follow-up was 33 months.

RESULTS

Four to five laminae were involved in all patients.The mean operation time was 180 min. Complications occurred in two patients of BL group, with immediate postoperative neurological deterioration due to ventral displacement of the laminae. Overall, the average sagittal diameter (SD) of the spinal canal increased from 9.2 +/- 1.3 mm to 12.4 +/- 1.3 mm after surgery. The average enlargement of SD was significantly higher for the OD group (p < 0.0075 ). In total, the improvement rate was 38% according to the Nurick grading and 69% according to the JOA score. For the OD group, improvement rates were 57% (Nurick) and 71% (JOA).

CONCLUSIONS

Decompressive laminoplasty is comparable with anterior surgery in neurological outcome. The OD technique seems to be superior to our BL technique regarding both the enlargement of SD and complication rate.

Minimum 2-year outcome of cervical laminoplasty with deep extensor muscle-preserving approach: impact on cervical spine function and quality of life

In this retrospective cohort study, two surgical methods of conventional open-door laminoplasty and deep extensor muscle-preserving laminoplasty were allocated for the treatment of cervical myelopathy, and were specifically compared in terms of axial pain, cervical spine function, and quality of life (QOL) with a minimum follow-up period of 2 years. Eighty-four patients were divided into two groups and received either a conventional open-door laminoplasty (CL group) or laminoplasty using a deep extensor muscle-preserving approach (MP group). The latter approach was performed by preserving multifidus and semispinalis cervicis attachments followed by open-door laminoplasty and re-suture of the bisected spinous processes at each decompression level. The average follow-up period was 38 months (25-53 months). The preoperative and follow-up evaluations included the original Japanese Orthopaedic Association (JOA) score, the new tentative JOA score including cervical spine function and QOL, and the visual analogue scale (VAS) of axial pain. Radiological analyses included cervical lordosis and flexion-extension range of motion (flex-ext ROM) (C2-7), and deep extensor muscle areas on MR axial images. The JOA recovery rates were statistically equivalent between two groups. The MP group demonstrated a statistically superior cervical spine function (84% vs 63%) and QOL (61% vs 45%) when compared to the CL group at final follow-up (P < 0.05). The average VAS scores at final follow-up were 2.3 and 4.9 in MP and CL groups (P < 0.05). The cervical lordosis and flex-ext ROM were statistically equivalent. The percent deep muscle area on MRI demonstrated a significant atrophy in CL group compared to that in MP group (56% vs 88%; P < 0.01). Laminoplasty employing the deep extensor muscle-preserving approach appeared to be effective in reducing the axial pain and deep muscle atrophy as well as improving cervical spine function and QOL when compared to conventional open-door laminoplasty.

Clinical feasibility of minimally invasive cervical laminoplasty

Minimally invasive approaches to the cervical spine for lateral disc herniation or foraminal stenosis have recently been described. Lower rates of blood loss, decreased narcotic dependence, and less tissue destruction as well as shorter hospital stays are all advantages of utilizing these techniques. These observations can also be realized with a minimal access approach to cervical laminoplasty. Multiple levels of the cervical spine can be treated from a posterior approach with the potential to decrease the incidences of postoperative axial neck pain and kyphotic deformity. In this report the authors present a concise history of the open laminoplasty technique, provide data from previous cadaveric studies (6 cases) along with recent clinical experience for minimally invasive laminoplasty, and describe the advantages and challenges of this novel procedure.