Surgical treatment for ossification of the posterior longitudinal ligament of the cervical spine

The Clinical Implications and Complications of Anterior Versus Posterior Surgery for Multilevel Cervical Ossification of the Posterior Longitudinal Ligament; An Updated Systematic Review and Meta-Analysis

OBJECTIVE

Theoretically, the optimal approach is determined by the status of ossification of the posterior longitudinal ligament (OPLL) and sagittal alignment. However, there have long been disputes about the optimum surgical approach of OPLL. This study is to compare risk-effectiveness between anterior decompression and fusion (ADF) and laminoplasty and laminectomy with fusion (LP/LF) for the patient with cervical myelopathy due to multilevel cervical OPLL.

METHODS

We searched core databases, and compared complication and outcomes between ADF and LP/LF for patients with multiple OPLL for the cervical spine. The incidence of complications such as neurologic deterioration, C5 palsy, and dura tear was assessed. Changes in JOA score between baseline and final evaluations were assessed for 2 groups. The minimal clinically important difference (MCID) was utilized for evaluating clinical significance. We calculated Peto odds ratio (POR) and mean difference for the incidence and continuous variables, respectively.

RESULTS

We included data from 21 articles involving 3,872 patients with cervical myelopathy with OPLL. Major neurologic deficits such as paraplegia, quadriplegia developed 2.17% in the ADF group and 1.11% in the LP/LF group, and POR was 2.16. Mean difference of JOA score improvement of 2 groups was 1.30, and the mean difference showed a statistical significance. However, 1.3 points of JOA improvement cannot reach 2.5 points of the MCID.

CONCLUSION

Anterior surgery often led to rare but critical complications, and the difference of neurological improvement between 2 groups was below a clinically meaningful level. Posterior surgeries may be appropriate in the treatment of multilevel cervical myelopathy with OPLL.

Influence of spinous process spacers on surgical outcome of laminoplasty for OPLL

Expansive laminoplasty for ossification of the posterior longitudinal ligament (OPLL) has had favorable outcomes. Many modifications of expansive laminoplasty have been developed, including expansive laminoplasty with and without spinous process spacers (SPS). The purpose of this study was to determine whether surgical outcomes were similar between expansive laminoplasty surgeries with and without SPS.Of 109 consecutive patients undergoing surgery for OPLL, 68 patients undergoing expansive laminoplasty were included in the study after excluding patients with other conditions affecting their functional status. The patients were divided into 2 groups based on their K-line, which connects the midpoints of the spinal canal at C2 and C7. Patients were further divided into 2 subgroups: those undergoing expansive laminoplasty without SPS (without SPS group) and those undergoing expansive laminoplasty with SPS (with SPS group). Surgical outcomes were evaluated between K-line (+) and K-line (-) groups. After dividing those groups further into the with SPS and without SPS groups, the differences in surgical outcomes were evaluated again.No significant difference existed in the recovery rate between the with SPS and without SPS groups and between the K-line (+) and K-line (-) groups. When the surgical outcome was only evaluated in the K-line (+) group, the recovery rate 1 year postoperatively was higher in patients without SPS than in those with SPS. Therefore, for patients with K-line (+), the possibility exists that SPS can restrict the posterior shift of the spinal cord and affect the surgical outcome.

Five-year follow-up evaluation of surgical treatment for cervical myelopathy caused by ossification of the posterior longitudinal ligament: a prospective comparative study of anterior decompression and fusion with floating method versus laminoplasty

STUDY DESIGN

Prospective, comparative clinical study.

OBJECTIVE

To compare the clinical outcome of anterior decompression and fusion with floating method and laminoplasty in the treatment of cervical myelopathy caused by ossification of the posterior longitudinal ligament (OPLL).

SUMMARY OF BACKGROUND DATA

There have been no reports that have accurately and prospectively compared surgical outcomes after anterior decompression and posterior decompression.

METHODS

For cervical myelopathy caused by OPLL, we performed anterior decompression and fusion with floating method (ADF) in 1997, 1999, 2001, 2003, and 2004 and French-door laminoplasty (LAMP) in 1996, 1998, 2000, and 2002 at one institution. Twenty patients in the ADF group and 22 patients in the LAMP group were evaluated for 5 years' follow-up. The following criteria were evaluated: operation time, blood loss, complications, and Japanese Orthopedic Association score. For radiographic evaluation, canal narrowing ratio of OPLL, lordotic angle at C2-C7, and postoperative progression of the ossified lesion were measured.

RESULTS

The operation time in the ADF group was longer than that in the LAMP group. The average blood loss showed no statistical difference between the 2 groups. Complications occurred in 5 cases in the ADF group, but none occurred in the LAMP group. The mean Japanese Orthopedic Association score system for cervical myelopathy and the recovery rate in the ADF group were superior to those in the LAMP group, especially for cases with greater than 50% of the spinal canal compromised by OPLL or kyphotic alignment of the cervical spine, preoperatively. Postoperative progression of OPLL was observed in 5% of the ADF group and 50% of the LAMP group.

CONCLUSION

ADF is considered especially suitable for cases with massive OPLL and preoperative kyphotic alignment of the cervical spine, although it leads to a higher incidence of surgery-related complications compared with LAMP.

Systematic review of cohort studies comparing surgical treatment for multilevel ossification of posterior longitudinal ligament: anterior vs posterior approach

There have been no standards or guidelines for the treatment of ossification of posterior longitudinal ligament, especially multilevel ossification of posterior longitudinal ligament. The purpose of this study was to compare results of major surgical treatment for multilevel ossification of posterior longitudinal ligament. Databases including MEDLINE, EMBASE, the Cochrane library, and bibliographies of identified and review articles were searched to find randomized, controlled trials or retrospective cohort studies comparing anterior and posterior approach from 1980 to December 2010. Approximately 1375 articles were found initially, 92 abstracts were screened, 23 articles were retrieved in full; 3 studies were included in the review. No randomized, controlled studies were identified. Because all the studies included in this study are cohort studies with disparity of surgical interventions, heterogeneity of outcome measures and different qualities, we were unable to perform a meta-analysis. All comparison studies are retrospective cohort studies, comparing surgical outcomes of anterior approach (corpectomy and fusion) with that of posterior approach (laminoplasty or laminectomy) for the treatment of multilevel ossification of posterior longitudinal ligament in the cervical spine. A systematic review of retrospective cohort studies was performed to determine which surgical treatment is the most effective in patients with multilevel ossification of posterior longitudinal ligament. Definitive conclusions regarding the surgical treatment of multilevel ossification of posterior longitudinal ligament could not be made in this article. Multilevel corpectomy and fusion are more technical and have a significantly higher rate of cerebrospinal fluid leakage and graft, instrumentation related complications. A well-designed, prospective, randomized controlled, multicenter trial is needed.

A prospective randomized study of clinical outcomes in patients with cervical compressive myelopathy treated with open-door or French-door laminoplasty

STUDY DESIGN

A prospective randomized clinical study.

OBJECTIVE

To compare the clinical outcomes of open-door and French-door laminoplasties.

SUMMARY OF BACKGROUND DATA

Expansive laminoplasty for cervical compressive myelopathy is well established and a variety of modifications procedures have been developed. The procedures are mainly classified into open-door and French-door. It has never been prospectively investigated as to which surgical procedure, open-door or French-door laminoplasty, results in a more favorable outcome.

METHODS

After informed consent was obtained from 40 patients, they were randomized into 2 surgical groups A and B. Patients in group A had open-door laminoplasty, and patients in group B underwent French-door laminoplasty with reattachment of the spinous process and extensor musculatures. The following criteria were evaluated: operation time, blood loss, perioperative complications, Japanese Orthopedic Association (JOA) scores, recovery rates, axial pain, and short-form 36 (SF-36). For radiographic evaluation, cervical lordosis was reviewed as lordotic angles, which were measured at C2-C7.

RESULTS

Although the operation time was significantly less in group A as compared with group B, the mean blood loss in group A was significantly more than group B. Perioperative complications occurred more frequently in group A than in group B. Although there were no significant differences in postoperative JOA scores and recovery rates between the 2 groups, axial pain was significantly decreased in group B at final follow-up. The scores of every subscale of the SF-36 were higher in group B than group A.

CONCLUSION

Perioperative complications occurred more frequently in open-door laminoplasty than in French-door laminoplasty. JOA scores and recovery rates suggested that both open-door and French-door laminoplasties could be similarly effective in decompressing the spinal cord. Axial pain was improved in French-door laminoplasty but became worse in open-door laminoplasty. SF-36 suggested that French-door laminoplasty could be more beneficial than open-door laminoplasty for patients with cervical compressive myelopathy.

Cervical spondylosis: ventral or dorsal surgery

Cervical spondylosis is a result of degenerative changes of the cervical spine. Neurological symptoms of myelopathy result from the narrowing of the spinal canal, causing spinal cord compression. Surgical management of cervical stenosis requires an understanding of the interplay between multiple pathological and biomechanical factors contributing to this disease process. Surgical decompression can be addressed from a ventral, dorsal, or combined approach. The authors discuss the technical aspects of the surgical decision making process regarding the decision to approach the spine from a ventral or dorsal orientation.

An analysis of factors causing poor surgical outcome in patients with cervical myelopathy due to ossification of the posterior longitudinal ligament: anterior decompression with spinal fusion versus laminoplasty

OBJECTIVE

We compared the surgical outcome of anterior decompression with spinal fusion (ASF) with the surgical outcome of laminoplasty for patients with cervical myelopathy due to ossification of the posterior longitudinal ligament.

METHODS

The study group comprised 19 ASF patients (A-group) and 40 laminoplasty patients (P-group) treated from 1993 to 2002 with 1 year or longer follow-up. The Japanese Orthopedic Association scoring system was used to evaluate cervical myelopathy, and the recovery rate calculated 1 year after surgery.

RESULTS

The mean recovery rate was 68.4% in the A-group and 52.5% in the P-group (P<0.05). Fifteen patients had a recovery rate less than 40%: 2 in the A-group and 13 in the P-group. One P-group patient and none of the A-group patients developed postoperative aggravation of their neurologic status. The P-group was divided into 2 subgroups: a good outcome group comprising patients whose recovery rate was 40% or higher (n=27) and a poor outcome group comprising patients whose recovery rate was less than 40% (n=13). The mean age at surgery was 59.9 years in the good outcome group and 68.0 years in the poor outcome group (P<0.05). The mean range of intervertebral mobility at maximum cord compression level before surgery was 6.9 degrees in the good outcome group and 10 degrees in the poor outcome group (P<0.05).

CONCLUSIONS

These results demonstrated that the surgical outcome of ASF was superior to the surgical outcome of laminoplasty. Elderly patients treated with laminoplasty showed an especially poor surgical outcome. We suggest that hypermobility of vertebrae at the cord compression level is a risk factor for poor surgical outcome after laminoplasty. Based on these results, we recommend that ASF should be the first choice of treatment for patients with significant ossification of the posterior longitudinal ligament and a hypermobile cervical spine. When laminoplasty is used for such cases, the addition of posterior instrumented fusion would be desirable for stabilizing the spine and decreasing damage to the spinal cord.

Long-term results of expansive open-door laminoplasty for ossification of the posterior longitudinal ligament of the cervical spine

OBJECT

Numerous surgical procedures have been developed for treatment of ossification of the posterior longitudinal ligament (OPLL) of the cervical spine, and these can be performed via three approaches: anterior, posterior, or combined anterior-posterior. The optimal approach in cases involving OPLL-induced cervical myelopathy, however, remains controversial. To address this issue, the authors assessed the benefits and limitations of expansive open-door laminoplasty for OPLL-related myelopathy by evaluating mid- and long-term clinical results.

METHODS

Clinical results obtained in 72 patients who underwent expansive open-door laminoplasty between 1983 and 1997 and who were followed for at least 5 years were assessed using the Japanese Orthopaedic Association (JOA) scoring system. The mean preoperative JOA score was 9.2 +/- 0.4; at 3 years postoperatively, the JOA score was 14.2 +/- 0.3 and the recovery rate (calculated using the Hirabayashi method) was 63.1 +/- 4.5%, both having reached their highest level. These favorable results were maintained up to 5 years after surgery. An increase in cervical myelopathy due to progression of the ossified ligament was observed in only two of 30 patients who could be followed for more than 10 years. Severe surgery-related complications were not observed. Preoperative JOA score, age at the time of surgery, and duration between onset of initial symptoms and surgery affected clinical results.

CONCLUSIONS

Mid-term and long-term results of expansive open-door laminoplasty were satisfactory. Considering factors that affected surgical results, early surgery is recommended for OPLL of the cervical spine.

Cervical laminoplasty: a critical review

OBJECT

The technique of cervical laminoplasty was developed to decompress the spinal canal in patients with multi-level anterior compression caused by ossification of the posterior longitudinal ligament or cervical spondylosis. There is a paucity of data confirming its superiority to laminectomy with regard to neurological outcome, preserving spinal stability, preventing postlaminectomy kyphosis, and the development of the "postlaminectomy membrane."

METHODS

The authors conducted a metaanalysis of the English-language laminoplasty literature, assessing neurological outcome, change in range of motion (ROM), development of spinal deformity, and complications. Seventy-one series were reviewed, comprising more than 2000 patients. All studies were retrospective, uncontrolled, nonrandomized case series. Forty-one series provided postoperative recovery rate data in which the Japanese Orthopaedic Association Scale was used for assessing myelopathy. The mean recovery rate was 55% (range 20-80%). The authors of 23 papers provided data on the percentage of patients improving (mean approximately 80%). There was no difference in neurological outcome based on the different laminoplasty techniques or when laminoplasty was compared with laminectomy. There was postlaminoplasty worsening of cervical alignment in approximately 35% and with development of postoperative kyphosis in approximately 10% of patients who underwent long-term follow-up review. Cervical ROM decreased substantially after laminoplasty (mean decrease 50%, range 17-80%). The authors of studies with long-term follow up found that there was progressive loss of cervical ROM, and final ROM similar to that seen in patients who had undergone laminectomy and fusion. In their review of the laminectomy literature the authors could not confirm the occurrence of postlaminectomy membrane causing clinically significant deterioration of neurological function. Postoperative complications differed substantially among series. In only seven articles did the writers quantify the rates of postoperative axial neck pain, noting an incidence between 6 and 60%. In approximately 8% of patients, C-5 nerve root dysfunction developed based on the 12 articles in which this complication was reported.

CONCLUSIONS

The literature has yet to support the purported benefits of laminoplasty. Neurological outcome and change in spinal alignment are similar after laminectomy and laminoplasty. Patients treated with laminoplasty develop progressive limitation of cervical ROM similar to that seen after laminectomy and fusion.

Long-term results of expansive laminoplasty for ossification of the posterior longitudinal ligament of the cervical spine: more than 10 years follow up

Object. The authors report the long-term (more than 10-year) results of cervical laminoplasty for ossification of the posterior longitudinal ligament (OPLL) of the cervical spine as well as the factors affecting long-term postoperative course.

Methods. The authors reviewed data obtained in 92 patients who underwent cervical laminoplasty between 1982 and 1990. Three patients were lost to follow up, 25 patients died within 10 years of surgery, and 64 patients were followed for more than 10 years. Results were assessed using the Japanese Orthopaedic Association (JOA) scoring system for cervical myelopathy. The recovery rate was calculated using the Hirabayashi method. The mean neurological recovery rate during the first 10 years after surgery was 64%, which declined to 60% at the last follow-up examination (mean follow up 12.2 years). Late neurological deterioration occurred in eight patients (14%) from 5 to 15 years after surgery. The most frequent causes of late deterioration were degenerative lumbar disease (three patients), thoracic myelopathy secondary to ossification of the ligamentum flavum (two patients), or postoperative progression of OPLL at the operated level (two patients). Postoperative progression of the ossified lesion was noted in 70% of the patients, but only two patients (3%) were found to have related neurological deterioration. Additional cervical surgery was required in one patient (2%) because of neurological deterioration secondary to progression of the ossified ligament. The authors performed a multivariate stepwise analysis, and found that factors related to better clinical results were younger age at operation and less severe preexisting myelopathy. Younger age at operation, as well as mixed and continuous types of OPLL, was highly predictive of progression of OPLL. Postoperative progression of kyphotic deformity was observed in 8% of the patients, although it did not cause neurological deterioration.

Conclusions. When the incidence of surgery-related complications and the strong possibility of postoperative growth of OPLL are taken into consideration, the authors recommend expansive and extensive laminoplasty for OPLL.

A comparative study of surgical approaches for cervical compressive myelopathy

Since 1986, the authors have used anterior decompression and fusion to treat patients with one- or two-level lesions without spinal canal stenosis (Group A) and laminoplasty for patients with more than three-level lesions or spinal canal stenosis (Group P). The aim of this study was to compare surgical outcomes of anterior and posterior approaches for patients with cervical myelopathy because of spondylosis and disc herniation and to determine the cause of poor neurologic recovery after surgery. One hundred thirty-six patients were followed up for an average of 5.6 years. There were no significant differences in gender, preoperative neurologic deficits, axial symptoms, or duration of symptoms before surgery between the two groups. Mean recovery rates for disc herniations were 71.1% and 71.9% in Groups A and P, respectively. For spondylosis, mean recovery rates were 49.0% and 58.6% in Groups A and P, respectively. There were no differences in recovery rate for patients with either spinal disorder between Groups A and P. The neurologic recovery of patients with kyphotic spinal cord was inferior to that of patients with lordotic or straight spinal cord. It is possible that acquisition and maintenance of lordosis result in improvement of clinical outcomes after surgery for patients with myelopathy.

A new surgical technique: open-window corpectomy in the treatment of ossification of the posterior longitudinal ligament and advanced cervical spondylosis: technical note

OBJECTIVE

To achieve satisfactory cervical spinal cord decompression with minimal removal of bone.

METHODS

The open-window corpectomy technique is designed to remove a minimal amount of bone and achieve satisfactory decompression. With the use of a high-speed drill under a surgical microscope, only the dorsal surface of the corpus is removed after appropriate microdiscectomies. This leaves the anterior and the lateral portions of the vertebral corpus intact.

RESULTS

In a 15-month period, a total of 11 patients were treated with this technique. Five patients improved, and the remaining six patients remained the same neurologically during a mean follow-up period of 8.3 months. No complications were observed in any patients.

CONCLUSION

The open-window corpectomy provides satisfactory spinal cord decompression in a biomechanically sound manner.

Expansive laminoplasty for myelopathy in ossification of the longitudinal ligament

Laminectomy, which had long been used for treatment of cervical spondylotic myelopathy, including ossification of the longitudinal ligament in the cervical spine, had numerous complications such as postoperative malalignment of the cervical spine and vulnerability of the spinal cord caused by total removal of the posterior structures. In 1977 Hirabayashi devised an open door expansive laminoplasty, which is a relatively easier and safer procedure than laminectomy, that eliminated such problems by preserving the posterior elements. The decompression effect of the expansive laminoplasty against a compressed spinal cord is comparable with that of laminectomy and anterior decompression followed by fusion, whereas the expansive laminoplasty has no structural problems and adverse effects on adjacent disc levels that often are associated with anterior decompression followed by fusion. Average recovery rate of expansive laminoplasty for cervical spondylotic myelopathy has been reported to be approximately 60% (Japanese Orthopaedic Association score) and with long term stability. At present, authors consider all patients with cervical spondylotic myelopathy candidates for expansive laminoplasty except for those having preoperative kyphosis and single level lesion without canal stenosis. Two remaining problems of expansive laminoplasty to be solved are prevention of C5,C6 radicular pain and/or paresis, the most frequent complication that occurs in approximately 5% to 10% of the patients, although most complications resolve spontaneously within 2 years, and correction of nonlordotic alignment to lordosis which are essential for posterior decompression effect of expansive laminoplasty by allowing the spinal cord to shift dorsally.

[Ossification of the posterior longitudinal ligament in the cervical spine: case report]

Ossification of the posterior longitudinal ligament (OPLL) is an uncommon cause of compressive myelopathy in the Caucasian population. A case of spastic paraparesis in a Caucasian man whose radiological investigation showed OPLL is presented. The radiographs of the cervical spine showed a strip of bony density posterior to the vertebral bodies, extending from C2 to T1. Computerized tomography (CT) and CT myelography showed OPLL at the same level. Magnetic resonance showed an area of increased signal on T2-weighted sequences at C7-T1 level suggestive of myelomalacia. The patient underwent an open-door laminoplasty (C2 to C7) with improvement of the paraparesis. OPLL should be included in the differential diagnosis of cervical myelopathy. It can be easily detected by plain radiographs and CT of the cervical spine. A review of the clinical and radiological features and the treatment of OPLL is presented.

Magnetic resonance imaging findings in ossification of the posterior longitudinal ligament of the cervical spine

OBJECT

Because of the lack of magnetic resonance (MR) signal from cortical bones, MR imaging is inadequate for diagnosing ossified lesions in the spinal canal. However, MR imaging provides important information on spinal cord morphology and associated soft-tissue abnormality. The purpose of this study is to determine the role of MR imaging in the diagnosis and treatment of patients with ossification of the posterior longitudinal ligament (OPLL) of the cervical spine.

METHODS

The authors reviewed MR imaging findings in 42 patients with cervical OPLL who were examined with a superconducting MR imaging system. The types of OPLL reviewed included eight cases of continuous, 21 cases of segmental, and 13 cases of the mixed type. All patients were treated surgically either by anterior (26 cases) or posterior decompression (16 cases).

CONCLUSIONS

The T1-weighted images clearly demonstrated the spinal cord deformity caused by OPLL. Associated disc protrusion was found to be present at the maximum compression level in 60% of the patients in this series. The highest incidence of disc protrusion (81%) was found in patients with segmental OPLL. Intramedullary hyperintensity on T2*-weighted imaging was noted in 18 patients (43%). The neurological deficits observed in these 18 patients were significantly more severe than those observed in the other 24 patients. Postoperative MR imaging revealed improvement in the spinal cord deformity, although the intramedullary hyperintensity was still observed in most cases. The present study demonstrates the importance of associated disc protrusion in the development of myelopathy in patients with cervical OPLL. Magnetic resonance imaging findings may be used to help determine the actual levels of spinal cord compression and to suggest the method of surgical treatment.

Anterior decompression and fusion using bone grafts obtained from cervical vertebral bodies for ossification of the posterior longitudinal ligament of the cervical spine: technical note

OBJECTIVE

To describe a surgical technique of anterior decompression and fusion using bone grafts obtained from cervical vertebral bodies with ossification of the posterior longitudinal ligament of the cervical spine. This technique seeks to avoid complications associated with an anterior approach of decompression and bone fusion, which widely uses autogenous bone from the iliac crest.

METHODS

Forty patients with cervical myelopathy were studied. The ossified ligament was localized to one, two, three, four, five, six, and seven vertebral bodies in 10, 18, 5, 4, 1, 1, and 1 patients, respectively. The ossified area of all posterior longitudinal ligament was completely removed using microsurgical techniques, and 11 patients were operated on at one level, 21 at two levels, and 8 at three levels.

RESULTS

The symptoms of all patients improved after the operation. Postoperative x-ray films showed solid bone fusion in all patients at a mean follow-up time of 3 years (range, 1-5.25 yr). Anterior angulation was found in one of eight patients (13%) who underwent three-level fusion.

CONCLUSION

Two major advantages were as follows: 1) no complications related to the iliac donor site occurred, and 2) early mobilization of patients was possible with a soft cervical collar. Anterior decompression and fusion should be used for cases with ossification of up to three consecutive vertebrae needing either one- or two-level fusions.

Anterior decompressive surgery for cervical ossified posterior longitudinal ligament causing myeloradiculopathy

This paper reviews 88 patients (74 males and 14 females) who underwent anterior decompression and fusion for symptomatic ossified posterior longitudinal ligament of the cervical spine. Follow up averaged 8.5 years. Eighteen patients underwent one-vertebra, 59 two-vertebra, and 11 three-vertebra decompression with interbody fusion. The preoperative severity of symptoms significantly affected neurological recovery. Patients with three-vertebra spondylectomy showed significantly little neurological improvement. The return of patients to their previous activities as monitored at follow up was related to their preoperative neurological status. MRI findings appeared to be relevant to neurological recovery. Our findings suggest that anterior decompression is to be recommended for patients with less advanced preoperative symptoms and the involvement of one or two vertebrae.