Surgical management of cervical myelopathy: indications and techniques for laminectomy and fusion

Current trends in demographics, practice, and in-hospital outcomes in cervical spine surgery: a national database analysis between 2002 and 2011

STUDY DESIGN

Retrospective database analysis.

OBJECTIVE

To investigate national trends of cervical spine surgical procedures from 2002 to 2011.

SUMMARY OF BACKGROUND DATA

There is a paucity of literature assessing the current practice trends and outcomes of cervical spine surgery following the 2008 Food and Drug Administration public health notifications regarding bone morphogenetic protein (BMP) utilization in cervical spine surgical procedures.

METHODS

The National Inpatient Sample database was accessed for each year across 2002 to 2011. Patients undergoing anterior cervical fusion, posterior cervical fusion, and posterior cervical decompression were identified. Patient and hospitalization parameters including demographics, BMP utilization, costs, early postoperative outcomes, and mortality were assessed for each surgical cohort. A Pearson correlation coefficient with a 95% confidence interval (P < 0.05) was used to analyze trends in patient and hospital outcome parameters during this 10-year period.

RESULTS

A total of 307,188 cervical spine procedures were performed from 2002 to 2011. Both the anterior cervical fusion and posterior cervical fusion cohort demonstrated a statistically significant increase in the number of procedures performed over time (r = +0.9, P < 0.001). A significant uptrend in patient age (r = +1.0, P < 0.001) and comorbidity burden (r = +0.9, P < 0.001) was demonstrated during the studied decade. Overall, BMP utilization (r = +0.7, P = 0.02) also demonstrated a significant increase during this time period, but demonstrated a decline after peaking in 2007. The posterior cervical fusion cohort demonstrated the greatest comorbidity, length of stay, costs, and mortality.

CONCLUSION

This study demonstrates that the number of cervical spine procedures has increased between 2002 and 2011, irrespective of the change in BMP utilization after the 2008 Food and Drug Administration warning. Despite an older patient population with greater comorbidities undergoing cervical spine surgeries, hospital length of stay and mortality has not significantly changed. However, we did note a significant increase in costs during this time period. These findings may be related to advances in surgical technology and instrumentation that may be associated with rising hospital costs.

Surgical management of cervical spondylotic myelopathy - indications for anterior, posterior or combined procedures for decompression and stabilisation

BACKGROUND

The authors describe their experience with the choice of anterior, posterior and combined approaches for the surgical treatment of spondylotic myelopathy.

METHODS

Description of surgical anatomy, surgical technique, indications, limitations, complications, specific perioperative considerations and specific information to give to the patient about surgery and potential risks and a summary of 10 key points is given.

CONCLUSIONS

If the disease extends behind the posterior vertebral body and if reestablishing spinal sagittal and coronal balance is an aim, then the anterior approach is the best choice. In cases of predominant posterior spinal cord compression and lordotic configuration the posterior approach should be preferred. Decompression of three or more levels, especially in combination with poor bone quality, requires a combined approach.

Spinal stenosis

Narrowing of the spinal canal or foramina is a common finding in spine imaging of the elderly. Only when symptoms of neurogenic claudication and/or cervical myelopathy are present is a spinal stenosis diagnosis made, either of the lumbar spine, cervical spine or both (only very rarely is the thoracic spine involved). Epidemiological data suggest an incidence of 1 case per 100 000 for cervical spine stenosis and 5 cases per 100 000 for lumbar spine stenosis. Cervical myelopathy in patients over 50 years of age is most commonly due to cervical spine stenosis. Symptomatic spinal narrowing can be congenital, or, more frequently, acquired. The latter may be the result of systemic illneses, namely endocrinopathies (such as Cushing disease or acromegaly), calcium metabolism disorders (including hyporarthyroidism and Paget disease), inflammatory diseases (such as rheumathoid arthritis) and infectious diseases. Physical examination is more often abnormal in cervical spondylotic myeloptahy whereas in lumbar spinal stenosis it is typically normal. Therefore spinal stenosis diagnosis relies on the clinical picture corresponding to conspicuous causative changes identified by imaging techniques, most importantly CT and MRI. Other ancillary diagnostic tests are more likely to be yielding for establishing a differential diagnosis, namely vascular claudication. Most patients have a progressive presentation and are offered non operative management as first treatment strategy. Surgery is indicated for progressive intolerable symptoms or, more rarely, for the neurologically catastrophic initial presentations. Surgical strategy consists mainly of decompression (depending on the anatomical level and type of narrowing: laminectomy, foraminotomy, discectomy, corporectomy) with additional instrumentation should spinal stability and sagittal balance be at risk. For cervical spine stenosis the main objective of surgery is to halt disease progression. There is class 1b evidence that surgery is of benefit for lumbar stenosis at least in the short term.

Anterior versus posterior surgical approaches to treat cervical spondylotic myelopathy: outcomes of the prospective multicenter AOSpine North America CSM study in 264 patients

STUDY DESIGN

A prospective observational multicenter study.

OBJECTIVE

To help solve the debate regarding whether the anterior or posterior surgical approach is optimal for patients with cervical spondylotic myelopathy (CSM).

SUMMARY OF BACKGROUND DATA

The optimal surgical approach to treat CSM remains debated with varying opinions favoring anterior versus posterior surgical approaches. We present an analysis of a prospective observational multicenter study examining outcomes of surgical treatment for CSM.

METHODS

A total of 278 subjects from 12 sites in North America received anterior/posterior or combined surgery at the discretion of the surgeon. This study focused on subjects who had either anterior or posterior surgery (n = 264, follow-up rate, 87%). Outcome measures included the modified Japanese Orthopedic Assessment scale, the Nurick scale, the Neck Disability Index, and the Short-Form 36 (SF-36) Health Survey version 2 Physical and Mental Component Scores.

RESULTS

One hundred and sixty-nine patients were treated anteriorly and 95 underwent posterior surgery. Anterior surgical cases were younger and had less severe myelopathy as assessed by mJOA and Nurick scores. There were no baseline differences in Neck Disability Index or SF-36 between the anterior and posterior cases. Improvement in the mJOA was significantly lower in the anterior group than posterior group (2.47 vs. 3.62, respectively, P < 0.01), although the groups started at different levels of baseline impairment. The extent of improvement in the Nurick Scale, Neck Disability Index, SF-36 version 2 Physical Component Score, and SF-36 version 2 Mental Component Score did not differ between the groups.

CONCLUSION

Patients with CSM show significant improvements in several health-related outcome measures with either anterior or posterior surgery. Importantly, patients treated with anterior techniques were younger, with less severe impairment and more focal pathology. We demonstrate for the first time that, when patient and disease factors are controlled for, anterior and posterior surgical techniques have equivalent efficacy in the treatment of CSM.

LEVEL OF EVIDENCE

3.

Cervical spinous process reconstruction

Posterior neck deformity with an unsightly crater-like defect may result after cervicothoracic laminectomies. The authors present a new technique, spinous process reconstruction, to address this problem. A 64-year-old man presented with progressive quadriparesis secondary to cervical spondylotic myelopathy. Previously he had undergone multiple neck surgeries including cervicothoracic decompressive laminectomy. Postoperatively, he developed severe craniocervical spinal deformity and a large painful concave surgical defect in the neck. The authors performed craniocervical decompression and craniocervicothoracic instrumented stabilization. At the same time, cervicothoracic spinous process reconstruction was performed using titanium mesh to address the defect. Cervicothoracic decompressive laminectomy results in varying degrees of neck defect with resulting unsightly and an often painful surgical wound defect despite an appropriate multilayer closure. The presented spinous process reconstruction is a simple technique to address this problem with good clinical outcome.

Surgical technique: Hemilaminectomy and unilateral lateral mass fixation for cervical ossification of the posterior longitudinal ligament

BACKGROUND

Surgical approaches for cervical ossification of the posterior longitudinal ligament (OPLL) include anterior, posterior, or combined decompression with or without fusion. The goal of surgery is to decompress the spinal cord while maintaining the stability and sagittal alignment of the cervical spine. C5 palsy has been reported as a postoperative complication of cervical laminectomy or laminoplasty characterized as motor weakness of the muscles supplied with C5 nerve roots. Several studies have shown this phenomenon was partially attributable to posterior shift of spinal cord.

DESCRIPTION OF TECHNIQUE

The rationale for choosing hemilaminectomy is to control postoperative posterior shift of the spinal cord and afford more stability by preserving ligamentous attachments and posterior bony elements as much as possible. After a fixation system of lateral mass screws and rods is installed unilaterally, laminae are removed from the underlying dura using a high-speed burr and Kerrison laminectomy rongeur on the other side. The spinous processes are preserved.

PATIENTS AND METHODS

Patients with multilevel continuous/mixed cervical OPLL are good candidates for this technique. We retrospectively reviewed 146 patients who had multilevel continuous/mixed cervical OPLL and underwent surgery from January 2006 to January 2010. Neurologic condition was evaluated using the improvement ratio (IR) of the Japanese Orthopaedic Association (JOA) score for cervical myelopathy.

RESULTS

The mean JOA score increased from 10 points before surgery to 14 points at last followup. The mean IR of neurologic function (JOA score) was 59%. C5 palsy was not observed in any patient after decompression, and cervical lordosis changed from 8.7° preoperatively to 9.1° at last followup.

CONCLUSIONS

For patients with multilevel continuous/mixed cervical OPLL without fixed kyphosis, multilevel hemilaminectomy with unilateral lateral mass fixation is an effective alternative technique.

LEVEL OF EVIDENCE

Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Is posterior fusion necessary with laminectomy in the cervical spine?

Background:

Cervical decompressive laminectomy is a common procedure for addressing multilevel cervical spine pathology. The most common reasons for performing simultaneous posterior cervical fusion include the prevention of progressive postlaminectomy kyphotic deformity or other types of instability which can contribute to late neurological deterioration.

Methods:

The medical literature (Pub Med with MeSH) concerning cervical laminectomy, posterior cervical fusion, and complications of laminectomy/fusion was reviewed. Additionally, references from the articles were queried to find additional literature.

Results:

Multiple studies concluded that cervical laminectomy versus laminectomy and fusion produced similar short-term postoperative outcomes. Careful patient selection was warranted to minimize the complications associated with cervical laminectomy alone; these included postoperative kyphosis (6–46%) and late deterioration (10–37%). The addition of a posterior cervical fusion was associated with relatively low complication rates, and avoided the evolution of late deformity or delayed neurological deterioration.

Conclusion:

Although the short-term results of cervical laminectomy versus laminectomy and fusion are similar, there appear to be more complications associated with performing laminectomy alone over the long term. Here, we reviewed the pros and cons of posterior cervical decompression alone versus decompression with fusion/instrumentation to treat cervical pathology, highlighting the complications associated with each surgical alternative.

Adjacent-level range of motion and intradiscal pressure after posterior cervical decompression and fixation: an in vitro human cadaveric model

STUDY DESIGN

This in vitro human cadaveric study measured adjacent-level kinematics after posterior cervical decompression and fixation.

OBJECTIVE

Quantify adjacent-level changes in range of motion (ROM) and intradiscal pressure after posterior cervical decompression and fixation.

SUMMARY OF BACKGROUND DATA

Optimal length of instrumentation after posterior decompression is unclear. Longer posterior cervical fixation constructs may increase the risk of adjacent-segment degeneration.

METHODS

Eight cervicothoracic spines were evaluated intact, with C3-C6 laminectomy, C3-C6 laminectomy + C3-C6 fixation, C3-C6 laminectomy + C3-C7 fixation, C3-C7 laminectomy, C3-C7 laminectomy + C3-C7 fixation, C3-C7 laminectomy + C2-C7 fixation, C3-C7 laminectomy + C3-T2 fixation, and C3-C7 laminectomy + C2-T2 fixation. Testing included intact moments (± 2.0 N·m) in flexion/extension, axial rotation, and lateral bending, with quantification of ROM at C2-C3, C6-C7, and C7-T1 normalized to the intact spine. Intradiscal pressures were also measured at each level.

RESULTS

For the C3-C6 laminectomy group, there were no differences in adjacent-level flexion/extension ROM or intradiscal pressure based on construct length, except at C6-C7, where ROM was significantly decreased when fixation was extended to C7 (P < 0.05). After C3-C7 laminectomy and reconstruction, the greatest increase in C2-C3 flexion/extension ROM and intradiscal pressure occurred in the C3-T2 fixation subgroup (ROM: 348% [P < 0.05]; intradiscal pressure: 319 ± 243 psi [pounds per square inch] vs. 65 ± 41 psi intact [P < 0.05]). At C7-T1, the greatest increase in flexion/extension ROM and intradiscal pressure occurred after C2-C7 fixation (ROM: 531% [P < 0.05]; intradiscal pressure: 152 ± 83 psi vs. 21 ± 14 psi intact [P < 0.05]).

CONCLUSION

For C3-C6 laminectomy, instrumentation to C7 significantly decreased flexion/extension ROM and intradiscal pressure at C6-C7 without significantly increasing either measure at C2-C3 or C7-T1 relative to C3-C6 fixation. In the setting of a C3-C7 laminectomy, when instrumenting to either C2 or T2, consideration should be given to including both levels within these constructs.

Operative outcomes for cervical myelopathy and radiculopathy

Cervical spondylotic myelopathy and radiculopathy are common disorders which can lead to significant clinical morbidity. Conservative management, such as physical therapy, cervical immobilisation, or anti-inflammatory medications, is the preferred and often only required intervention. Surgical intervention is reserved for those patients who have intractable pain or progressive neurological symptoms. The goals of surgical treatment are decompression of the spinal cord and nerve roots and deformity prevention by maintaining or supplementing spinal stability and alleviating pain. Numerous surgical techniques exist to alleviate symptoms, which are achieved through anterior, posterior, or circumferential approaches. Under most circumstances, one approach will produce optimal results. It is important that the surgical plan is tailored to address each individual's unique clinical circumstance. The objective of this paper is to analyse the major surgical treatment options for cervical myelopathy and radiculopathy focusing on outcomes and complications.

Cervical spondylosis with spinal cord encroachment: should preventive surgery be recommended?

Background

It has been stated that individuals who have spondylotic encroachment on the cervical spinal cord without myelopathy are at increased risk of spinal cord injury if they experience minor trauma. Preventive decompression surgery has been recommended for these individuals. The purpose of this paper is to provide the non-surgical spine specialist with information upon which to base advice to patients. The evidence behind claims of increased risk is investigated as well as the evidence regarding the risk of decompression surgery.

Methods

A literature search was conducted on the risk of spinal cord injury in individuals with asymptomatic cord encroachment and the risk and benefit of preventive decompression surgery.

Results

Three studies on the risk of spinal cord injury in this population met the inclusion criteria. All reported increased risk. However, none were prospective cohort studies or case-control studies, so the designs did not allow firm conclusions to be drawn. A number of studies and reviews of the risks and benefits of decompression surgery in patients with cervical myelopathy were found, but no studies were found that addressed surgery in asymptomatic individuals thought to be at risk. The complications of decompression surgery range from transient hoarseness to spinal cord injury, with rates ranging from 0.3% to 60%.

Conclusion

There is insufficient evidence that individuals with spondylotic spinal cord encroachment are at increased risk of spinal cord injury from minor trauma. Prospective cohort or case-control studies are needed to assess this risk. There is no evidence that prophylactic decompression surgery is helpful in this patient population. Decompression surgery appears to be helpful in patients with cervical myelopathy, but the significant risks may outweigh the unknown benefit in asymptomatic individuals. Thus, broad recommendations for decompression surgery in suspected at-risk individuals cannot be made. Recommendations to individual patients must consider possible unique circumstances.