Clinical Equipoise and Treatment Decisions in Cervical Spondylotic Myelopathy

Value of Surgery and Nonsurgical Approaches for Cervical Spondylotic Myelopathy: WFNS Spine Committee Recommendations

Cervical spondylotic myelopathy (CSM) is a common cause of adult spinal cord dysfunction. Although the therapeutic options for moderate to severe CSM patients have been established well, the existing guidelines for therapeutic decisions in mild cases of CSM are unclear. We present a review of literature on conservative treatment and surgery for CSM and suggest general recommendations applicable in various clinical presentations and in different geographic locations across the globe, with due considerations to available resources and locally prevalent practices.

Commentary : The value of intraoperative neurophysiological monitoring: evidence, equipoise and outcomes

The use of intraoperative neurophysiological monitoring (IONM) has grown despite an absence of randomized controlled trials that might unequivocally demonstrate improved outcomes. At issue is how to demonstrate value when other evidence indicates patient harms (opportunity cost) if IONM is withheld for the sake of randomization. In this article we review other non-randomized methods to assess the effects of IONM on post-operative outcomes. We also examine how clinical equipoise may resolve whether (or not) an anticipated controlled study is ethical. We conclude that the value of IONM in a particular surgical setting should be determined by a benefits/harms analysis based on all the available evidence.

Functional outcome instruments used for cervical spondylotic myelopathy: interscale correlation and prediction of preference-based quality of life

BACKGROUND CONTEXT

There is limited literature comparing different functional outcome measures used for cervical spondylotic myelopathy (CSM).

PURPOSE

To determine the correlation among five functional outcome measures used in CSM patient assessment and their ability to predict preference-based quality of life (QOL).

STUDY DESIGN/SETTING

Prospective observational study.

PATIENT SAMPLE

Patients, aged 40 to 85 years, with CSM and cervical spinal cord compression at two or more levels from degenerative spondylosis were enrolled from seven sites over a 2-year period.

OUTCOME MEASURES

The modified Japanese Orthopedic Association scale, Oswestry neck disability index (Oswestry NDI or Oswestry), Nurick scale, norm-based short-form 36 physical component summary, and EuroQol-5D (EQ-5D) were collected.

METHODS

The Jean and David Wallace foundation provided funding for this study. Cervical spondylotic myelopathy patients undergoing either anterior or posterior surgery were prospectively followed with five different functional outcome measures over 1 year. Correlations among scales were tested using the Spearman rank correlation test. The sensitivity and specificity of each scale for predicting the global index of the EQ-5D were determined, and receiver-operating characteristic analysis was used to compare each scale's ability to discriminate QOL.

RESULTS

A total of 106 patients were initially enrolled; 103 were operated on for CSM and followed for 1 year. Their ages ranged from 40 to 82 years (mean 61.9), and 61.3% were men. Correlations among the various functional outcome instruments were all highly significant (p<.001), but the degree of correlation varied greatly. Correlation between the EQ-5D scale and the Nurick scale was the least (Spearman rho 0.5539); correlation was the highest with the Oswestry NDI (Spearman rho 0.8306). The Oswestry NDI also had the greatest ability to discriminate favorable from adverse QOL compared with the other outcome instruments (p=.023).

CONCLUSIONS

Preference-based quality-of-life instruments, such as the EQ-5D, are important measures for studying spinal disorders. Among the various commonly used outcome instruments for CSM, the Oswestry NDI is the most predictive of preference-based QOL.

Preoperative evaluation of the cervical spondylotic myelopathy with flexion-extension magnetic resonance imaging: about a prospective study of fifty patients

STUDY DESIGN

The authors evaluated preoperative modifications of the cervical spinal canal in flexion and extension in 50 patients with cervical spondylotic myelopathy (CSM) and looked for impingement of the spinal cord not diagnosed in the neutral position.

OBJECTIVE

To evaluate the usefulness of preoperative flexion-extension magnetic resonance imaging (MRI) for patients with CSM.

SUMMARY OF BACKGROUND DATA

Dynamic factors contribute to CSM. Although the clinical manifestations and spinal or spinal cord morphology in patients with myelopathy have been reported, to our knowledge, there are no studies that include the cervical spinal cord length, sagittal diameter, and available space in patients with CSM in flexion, extension, and the neutral position.

METHODS

Dynamic MRI changes in canal stenosis during flexion-extension were evaluated in 50 patients with CSM in the supine position. The authors determined length of the cervical cord (LCC, C1-C7), cervical cord sagittal diameter (CCSD, C3-T1), cervical cord available space (CCAS, C3-T1), intramedullary high-intensity signal (IHIS) changes, number of stenosis, and severity of cord impingement in flexion, extension, and the neutral positions.

RESULTS

On both the anterior and posterior edges of the cord, mean LCC in flexion was longer than in extension or the neutral position and longer in the neutral position than in extension (P < 0.05). In all three positions, the average length of the anterior edge of the cervical cord was longer than the posterior edge (P < 0.05). The mean value of CCSD at each level in extension was greater than in flexion or the neutral position (P < 0.05). In the neutral position, CCSDs were greater than in flexion from C4 to C7 (P < 0.05), but this difference failed to reach significance at levels C3 and T1. In the neutral position, CCAS was greater than in either extension or flexion (P < 0.05), and CCAS was greater in flexion than in extension (P < 0.05) at all levels except C6, at which CCAS was greater in flexion than in either extension or the neutral position (P < 0.05). MRI demonstrated functional cord impingement (grade 3 of Mühle) in 6 of the 50 (12%) patients in flexion, in 17 patients (34%) in the neutral position, and in 37 patients (74%) in extension. IHIS was observed in flexion in 20 patients (40%), in the neutral position in 13 patients (26%), and in extension in 7 patients (14%).

CONCLUSION

Cervical spondylotic myelopathy results from the synergistic action of static and dynamic factors, the latter of which play an important role. In some patients, IHIS on T2 images is only visible with the neck in flexion. That might explain why IHIS is first detected after surgery in some patients in whom MRI was obtained before surgery only in the neutral position. Dynamic MRI is useful to determine more accurately the number of levels where the spinal cord is compromised, and to better evaluate narrowing of the canal and IHIS. New information provided by flexion-extension MRI might change our strategy for CSM management.

Trends and variations in cervical spine surgery in the United States: Medicare beneficiaries, 1992 to 2005

STUDY DESIGN

Retrospective cohort.

OBJECTIVE

To describe population-based trends and variations in surgery for degenerative changes of the cervical spine among Medicare beneficiaries, 1992 to 2005.

SUMMARY OF BACKGROUND DATA

Degenerative changes of the cervical spine are seen radiographically in over half of the population aged 55 years or greater, and rates of cervical spine surgery have increased over time. Prior studies examined anterior cervical discectomy and fusion procedures in the general population up to 1999, and showed regional variations in care, with the highest rates in the South. The purpose of this study is to explore population-based trends and variations in surgery for degenerative changes of the cervical spine in the elderly.

METHODS

From 1992 to 2005, hospital admissions associated with surgery for degenerative changes of the cervical spine were selected from Medicare Part A using ICD9 CM codes. We excluded beneficiaries under 65 years of age, in a capitated health plan, or enrolled for Social Security Disability Income. Diagnosis and type of surgery were defined using ICD9 CM codes. Rates were directly adjusted to age, sex, and race of 2005 Medicare beneficiaries.

RESULTS

Of 156,820 qualifying admissions, 52% were men, 88% were white, and 41% were aged 65 to 69 years. The most common primary diagnosis and procedure were cervical spondylosis with myelopathy (36%) and fusion (70%); of the fusions, 58% were anterior. Rates of cervical fusions rose from 1992 to 2005 even after adjustment for age, sex, and race (14.7 to 45 cervical fusions/100,000 beneficiaries). Rates of cervical fusions varied by geographic location, with the highest rates in the Northwest and South Central regions. In 2005, the highest rate of cervical fusions was 140/100,000 beneficiaries in Idaho, compared with 4/100,000 beneficiaries in Washington, DC.

CONCLUSION

In the elderly, adjusted rates of cervical spine fusions rose 206% from 1992 to 2005. Marked geographic variation was noted. Future studies should evaluate the efficacy and complications associated with these procedures in the elderly, and better define surgical indications and patient outcome.