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

Updates in current concepts in degenerative cervical myelopathy: a systematic review

Background

The incidence of degenerative cervical myelopathy (DCM) has increased over the years due to an increasing aging population, yet there is a dearth of recent comprehensive data evaluating the multiple facets of this degenerative condition. Recent publications have highlighted the biochemistry and biomechanics of DCM, which are paramount to understanding the degenerative nature of the condition and selecting the most optimal treatment options for improved patient outcomes. In addition, there have been recent studies establishing the superiority of surgical to non-surgical treatments for DCM, which until now was a poorly substantiated claim that has permeated the medical field for decades. The authors of this systematic review sought to collect and assess available high quality peer reviewed data to analyze the nature of DCM and gain a better understanding for its treatment choices.

Methods

PubMed and Cochrane Central Register of Controlled Trials were systematically searched on January 19, 2023 with date restrictions of 2015-2023 imposed. For initial data collection, five independent searches were completed using the following keywords: pathogenesis, pathophysiology, and epidemiology of DCM; cervical spondylotic myelopathy (CSM) and DCM recent developments; management and treatment for CSM and DCM; diagnosis and management of DCM; and pathophysiology of DCM. The results were screened for their application to DCM; any study that did not directly address DCM were identified and removed through abstract assessment, such studies included those pertaining to alternative fields including cardiology and psychiatry. Studies found relevant through full-text assessment and those published in English were included in this study and unpublished studies and studies found irrelevant based on titles and keywords were excluded from this study. The 115 articles that met criteria were critically appraised independently by the 2 reviewers and the principles of Grading of Recommendations, Assessment, Development, and Evaluations (GRADE) were applied to assess the quality of evidence from each study.

Results

A total of 352 studies resulted from the original search. There were 71 duplicate articles that were removed and a total of 281 articles were screened. 166 articles were then removed based on the exclusion/inclusion criteria, title, and abstract. Of the 138 articles that remained, a final list of 115 articles was created based on the reporting measures.

Conclusions

DCM is a multifactorial disease that has the potential to impair neurological function and cause significant paralysis. Although the multiple facets of this disease have not been fully elucidated, there have been significant breakthroughs in understanding the mechanisms involved in this disease process. The use of complex imaging modalities, genetic sequencing, biomarkers, and pharmacological agents has provided insight into the factors involved in the progression of DCM, which has consequently cultivated more refined approaches for diagnosis and treatment of DCM.

Dynamic Flexion-Extension Magnetic Resonance Imaging of the Cervical Spine: An Evolutionary Tool for Diagnosis and Management of Cervical Spondylotic Myelopathy

Dynamic problems need dynamic solutions. High motility of the cervical spine causes a common age-related degenerative condition called cervical spondylotic myelopathy (CSM), manifested by neurological impairments. An accurate and reliable diagnosis of CSM is crucial for determining appropriate management strategies. Traditional static magnetic resonance imaging (MRI) has been the gold standard for imaging CSM; however, it may not fully capture dynamic changes during neck movement. Dynamic flexion-extension (DFE) MRI is an innovative imaging technique that allows for real-time visualization of cervical spine motion. This review article aims to scrutinize the role of DFE MRI in assessing CSM, its added value to clinical implementations, and its limitations. Finally, by addressing the knowledge gaps, this survey sheds light on the road ahead to incorporate DFE MRI into a standard version of the practice.

T2-weighted Imaging Hyperintensity and Transcranial Motor-evoked Potentials During Cervical Spine Surgery: Effects of Sevoflurane in 150 Consecutive Cases

BACKGROUND

There is debate on the impact of inhalational esthetic agents on transcranial motor evoked potentials (TcMEPs) during intraoperative neuromonitoring. Current guidelines advise their avoidance, which contrasts with common clinical practice.

METHODS

This retrospective cohort study of 150 consecutive cervical spine surgeries at a single institution compared stimulation voltages and TcMEP amplitudes in patients who did and did not receive sevoflurane as part of a balanced anesthetic technique. Patients were divided into 3 groups stratified by the presence or absence of increased signal intensity within the cervical spinal cord on T2-weighted magnetic resonance imaging (indicative or myelopathy/spinal cord injury [SCI]) and sevoflurane use.

RESULTS

Patients with no magnetic resonance imaging evidence of myelopathy/SCI that received sevoflurane (n=80) had the lowest stimulation voltages and largest TcMEP amplitude responses in the lower extremities compared with those with no magnetic resonance imaging evidence of myelopathy/SCI (n=30). In patients with evidence of myelopathy/SCI who did not receive sevoflurane (n=19), lower extremity TcMEP amplitudes were similar to patients with a myelopathy/SCI that received sevoflurane. Six of these 19 patients had initial low-dose sevoflurane discontinued because of concerns of low/absent baseline TcMEP amplitudes.

CONCLUSIONS

Balanced anesthesia with 0.5 MAC sevoflurane in patients with and without radiological evidence of myelopathy/SCI allows reliable TcMEP monitoring. However, in communication with surgical and neuromonitoring teams, it may be advisable in a subset of patients to avoid or discontinue sevoflurane in favor of a propofol/opioid-based anesthetic to ensure adequate and reproducible TcMEPs.

Natural history of degenerative cervical myelopathy: a meta-analysis and neurologic deterioration survival curve synthesis

BACKGROUND CONTEXT

Cervical spine surgery is rapidly increasing, and our knowledge of the natural history of degenerative cervical myelopathy (DCM) is limited.

PURPOSE

To synthesize accurate time-based estimates of meaningful neurologic decline in patients with DCM managed conservatively and to provide formulae to help communicate survivorship estimates to patients.

STUDY DESIGN

Systematic review and meta-analysis.

METHODS

A systematic review and meta-analysis was conducted using Cochrane and PRISMA guidelines. A librarian-assisted search strategy using multiple databases with broad search terms and validated filter functions was used. All articles were reviewed in duplicate.

RESULTS

A total of 9570 studies were captured in the initial search, which after deletion of duplicates and manual review of abstracts and full texts revealed 6 studies for analyses. All studies were prospective cohorts or randomized controlled trials. The pooled survival estimates for neurologic stability (95% CrI) for mild DCM patients are: 91% (83%-97%) at one year; 85% (72%-94%) at 2 years; 84% (70%-94%) at 3 years; 75% (54%-90%) at 5 years; 66% (40%-86%) at 15 years; and 65% (39%-86%) at 20 years. The pooled survival estimates for neurologic stability (95% CrI) for moderate/severe DCM patients are: 83% (76%-89%) at 1 year; 72% (62%-81%) at 2 years; 71% (60%-80%) at 3 years; 55% (41%-68%) at 5 years; 44% (27%-59%) at 15 years; and 43% (25%-58%) at 20 years.

CONCLUSIONS

This is the first quantitative synthesis of the totality of published data on DCM natural history. Our review confirms a slow decline in neurologic function. We developed formulae which can be easily used by surgeons to communicate to patients their risk of neurologic deterioration. These formulae can be used to facilitate the shared decision-making process.

Cervical Spondylotic Myelopathy: From the World Federation of Neurosurgical Societies (WFNS) to the Italian Neurosurgical Society (SINch) Recommendations

Cervical spondylotic myelopathy (CSM) is a progressively growing pathology to afford by a spinal surgeon due to the aging of the population, associated with better treatment management and the best diagnosis and treatment solutions are greatly discussed. Nowadays that scientific literature is progressively increasing to identify the gold standard in diagnosis and treatment can be very challenging. This is particularly evident in spinal surgery with many different indications not only in different countries but also in the same local reality. In this scenario, many neurosurgical societies works to identify some guideline or recommendations to help spinal surgeons in daily practice. Furthermore, in an era in which legal issues are increasingly present in clinical practice to have some indications globally accepted can be very useful. World Federation of Neurosurgical Societies (WFNS) few years ago starts this process creating a list of recommendations originating from a worldwide steering committee to respect all the local reality. The spinal section of Italian Neurosurgical Society decides to adopt the WFNS recommendations with some revision basing on Italian scenario. The steering committee of the Spinal Section of Italian Neurosurgical Society identify 7 groups to review the literature of the last 10 years about different topics on CSM and to analyses the WFNS recommendations to adapt it to the Italian daily practice. The statements were discussed and voted in 2 sessions to obtain the final version. A list of recommendations on natural course and clinical presentation; diagnostic tests; conservative and surgical treatment; anterior, posterior and combined surgical treatment; role of neurophysiological monitoring and follow-up and outcome was created with only few new or revised statements respect the ones of WFNS. The Spine Section of Italian Neurosurgical Society create a list of recommendations that represent the more contemporary treatment concepts for CSM as presented in the highest quality clinical literature and best clinical practices available on this subject.

Influence of Predominant Neck versus Arm Pain on Clinical Outcomes in Cervical Disc Replacement

OBJECTIVE

We aim to compare the postoperative clinical outcomes, through patient-reported outcome measures (PROMs) and minimum clinically important difference (MCID), in patients undergoing cervical disc replacement (CDR) with preoperative predominant neck pain (pNP) or arm pain (pAP).

METHODS

Patients undergoing primary CDR were separated into pNP or pAP cohorts. Demographic, perioperative characteristics, PROMs at preoperative and postoperative time points, and MCID were compared using inferential statistics. Assessed PROMs included Patient-Reported Outcome Measurement Information System-Physical Function (PROMIS-PF), 12-Item Short Form Physical/Mental Component Score (SF-12 PCS/MCS), visual analog scale (VAS) neck, VAS arm, and Neck Disability Index.

RESULTS

There were a total of 84 patients, with 54 patients in the pNP cohort. The pNP cohort showed significant postoperative improvement in all PROMs, except for 6-week and 1-year SF-12 PCS, 1-year SF-12 MCS, and 6-month VAS arm score (P ≤ 0.023, all). The pAP cohort showed significant postoperative improvement in all PROMs, apart from 6-month to 1-year SF-12 PCS, and all SF-12 MCS (P ≤ 0.041, all). Greater MCID achievement rates were found in the pNP cohort for SF-12 MCS (P = 0.030). The pAP cohort had higher MCID achievement rates in VAS arm score and Neck Disability Index (P ≤ 0.046, all).

CONCLUSIONS

Independent of predominant pain location, patients reported improved physical function, pain, and disability outcomes. Patients with pNP had higher MCID achievement rates in mental function. Patients with pAP had higher rates of MCID achievement in arm pain and disability outcomes. Considering the predominant location of preoperative pain may be helpful in managing expectations for patients undergoing CDR.

Surgical Strategies and Perioperative Considerations for Cervical Deformity With Cerebral Palsy: A Comprehensive Review of the Literature

The complex nature of the cervical spine makes surgical intervention challenging when treating cervical deformity in patients with cerebral palsy (CDCP). However, few studies have investigated the unique characteristics of cerebral palsy that create the need for surgery, the most effective surgical strategies, and the possible perioperative complications. The intended benefit and the potential risk of postoperative complications must be considered when deciding to operate for CDCP. Because the approach and correction strategy depend on the type of cervical deformity, as well as the patient's comorbidities and functional status, a customized strategy is needed. Perioperatively, botulinum toxin injections and muscle division techniques can help control excessive involuntary movements and improve the spinal fusion success rate. Surgical intervention for CDCP requires a multidisciplinary approach, and the information presented in this article is intended to help in the perioperative management and surgical treatment of CDCP.

Provision and Perception of Physiotherapy in the Nonoperative Management of Degenerative Cervical Myelopathy (DCM): A Cross-Sectional Questionnaire of People Living With DCM

STUDY DESIGN

Cross-sectional survey.

OBJECTIVES

Degenerative cervical myelopathy (DCM) is a common syndrome of acquired spinal cord impairment caused by canal stenosis secondary to arthritic changes of the spine. International guidelines consider physiotherapy an option for mild, stable DCM; however, few studies have been conducted on nonoperative management. The objective was to determine current usage and perceptions of nonoperative physiotherapy for DCM.

METHODS

Persons with DCM were recruited to a web-based survey. Participants with complete responses that had not received surgery were included (n = 167). Variables included symptom duration, treatment history, current disability, and demographic characteristics.

RESULTS

Disease and demographic characteristics were equivalent between those who did and did not receive physiotherapy. In all, 19.5% of physiotherapy recipients reported subjective benefit from physiotherapy. Those perceiving benefit had significantly higher mJOA (modified Japanese Orthopaedic Association) scores, lower neck pain scores, and shorter symptom duration. In multivariate logistic regression analysis, those with mild DCM were more likely to perceive benefit than those with severe DCM, as were those with moderate DCM (to a lesser extent). Individuals whose diagnosis was delayed 1 to 2 years were less likely to perceive benefit than those that waited 0 to 6 months.

CONCLUSIONS

The provision of nonoperative physiotherapy in the management of DCM is inconsistent and appears to differ from international guidelines. Few patients perceived benefit from physiotherapy; however, this was more likely in those with mild DCM and in those with shorter symptom durations. Further work is needed to establish the appropriate role of physiotherapy for this population.

Improving Awareness Could Transform Outcomes in Degenerative Cervical Myelopathy [AO Spine RECODE-DCM Research Priority Number 1]

STUDY DESIGN

Literature Review (Narrative).

OBJECTIVE

To introduce the number one research priority for Degenerative Cervical Myelopathy (DCM): Raising Awareness.

METHODS

Raising awareness has been recognized by AO Spine RECODE-DCM as the number one research priority. This article reviews the evidence that awareness is low, the potential drivers, and why this must be addressed. Case studies of success from other diseases are also reviewed, drawing potential parallels and opportunities for DCM.

RESULTS

DCM may affect as many as 1 in 50 adults, yet few will receive a diagnosis and those that do will wait many years for it. This leads to poorer outcomes from surgery and greater disability. DCM is rarely featured in healthcare professional training programs and has received relatively little research funding (<2% of Amyotrophic Lateral Sclerosis or Multiple Sclerosis over the last 25 years). The transformation of stroke and acute coronary syndrome services, from a position of best supportive care with occasional surgery over 50 years ago, to avoidable disability today, represents transferable examples of success and potential opportunities for DCM. Central to this is raising awareness.

CONCLUSION

Despite the devastating burden on the patient, recognition across research, clinical practice, and healthcare policy are limited. DCM represents a significant unmet need that must become an international public health priority.

Effectiveness of Surgical Decompression in Patients With Degenerative Cervical Myelopathy: Results of the Canadian Prospective Multicenter Study

BACKGROUND

Conflicting evidence exists regarding the effectiveness of surgery for degenerative cervical myelopathy (DCM), particularly in mild DCM.

OBJECTIVE

To prospectively evaluate the impact of surgery on patient-reported outcomes in patients with mild (modified Japanese Orthopaedic Association [mJOA] ≥ 15), moderate (mJOA 12-14), and severe (mJOA < 12) DCM.

METHODS

Prospective, multicenter cohort study of patients with DCM who underwent surgery between 2015 and 2019 and completed 1-yr follow-up. Outcome measures (mJOA, Neck Disability Index [NDI], EuroQol-5D [EQ-5D], Short Form [SF-12] Physical Component Score [PCS]/Mental Component Score [MCS], numeric rating scale [NRS] neck, and arm pain) were assessed at 3 and 12 mo postoperatively and compared to baseline, stratified by DCM severity. Changes in outcome measures that were statistically significant (P < .05) and met their respective minimum clinically important differences (MCIDs) were deemed clinically meaningful. Responder analysis was performed to compare the proportion of patients between DCM severity groups who met the MCID for each outcome measure.

RESULTS

The cohort comprised 391 patients: 110 mild, 163 moderate, and 118 severe. At 12 mo after surgery, severe DCM patients experienced significant improvements in all outcome measures; moderate DCM patients improved in mJOA, NDI, EQ-5D, and PCS; mild DCM patients improved in EQ-5D and PCS. There was no significant difference between severity groups in the proportion of patients reaching MCID at 12 mo after surgery for any outcome measure, except NDI.

CONCLUSION

At 12 mo after surgery, patients with mild, moderate, and severe DCM all demonstrated improved outcomes. Severe DCM patients experienced the greatest breadth of improvement, but the proportion of patients in each severity group achieving clinically meaningful changes did not differ significantly across most outcome measures.

Preoperative Radiological Parameters to Predict Clinical and Radiological Outcomes after Laminoplasty

Many studies have focused on pre-operative sagittal alignment parameters which could predict poor clinical or radiological outcomes after laminoplasty. However, the influx of too many new factors causes confusion. This study reviewed sagittal alignment parameters, predictive of clinical or radiological outcomes, in the literature. Preoperative kyphotic alignment was initially proposed as a predictor of clinical outcomes. The clinical significance of the K-line and K-line variants also has been studied. Sagittal vertical axis, T1 slope (T1s), T1s-cervical lordosis (CL), anterolisthesis, local kyphosis, the longitudinal distance index, and range of motion were proposed to have relationships with clinical outcomes. The relationship between loss of cervical lordosis (LCL) and T1s has been widely studied, but controversy remains. Extension function, the ratio of CL to T1s (CL/T1s), and Sharma classification were recently proposed as LCL predictors. In predicting postoperative kyphosis, T1s cannot predict postoperative kyphosis, but a low CL/T1s ratio was associated with postoperative kyphosis.

Perioperative Outcomes in 17,947 Patients Undergoing 2-Level Anterior Cervical Discectomy and Fusion Versus 1-Level Anterior Cervical Corpectomy for Treatment of Cervical Degenerative Conditions: A Propensity Score Matched National Surgical Quality Improvement Program Analysis

Objective

To compare the perioperative morbidity of 2-level anterior cervical discectomy and fusion (ACDF) with that of 1-level anterior cervical corpectomy and fusion (ACCF) for the treatment of cervical degenerative conditions.

Methods

A retrospective study of the 2005–2016 National Surgical Quality Improvement Program database for patients undergoing 2-level ACDF and 1-level ACCF was performed. Patient data included: age, sex, body mass index (BMI), functional status, and American Society of Anesthesiologists (ASA) physical status (PS) classification. Hospital data included: operative time and length of hospital stay (LOS). Thirty-day outcome data included: any, serious, and minor adverse events, return to the operating room, readmission, and mortality. After propensity matching for age, sex, ASA PS classification, functional status, and BMI, multivariate logistic regression analysis was used to compare outcomes between the 2 propensity-matched subcohorts. Finally, multivariate logistic regression that additionally controlled for operative time was performed to compare the 2 propensity-matched subcohorts.

Results

A total of 17,497 cases were identified, with 90.20% undergoing 2-level ACDF and 9.80% undergoing 1-level ACCF. Patients undergoing 2-level ACDF were younger, more likely to be female, had higher functional status, and had shorter operative time and LOS (p < 0.001). After propensity score matching, cases undergoing 1-level ACCF had a statistically significant higher rate of serious adverse events (p = 0.005). This difference was no longer significant after controlling for operative time.

Conclusion

While there was noted to be additional morbidity in 1-level ACCF cases relative to 2-level ACDF cases, the lack of difference once controlling for the surgical time supports using the procedure that best accomplishes the surgical objectives.

Clinical and radiological outcomes of multilevel cervical laminoplasty versus three-level anterior cervical discectomy and fusion in patients with cervical spondylotic myelopathy

Background

Cervical spondylotic myelopathy (CSM) is one of the most common causes of spinal cord impairment in elderly patients. However, a consensus has yet to be reached on the ideal method of surgical intervention. In this study, we investigated serial changes of radiological findings after three-level anterior cervical discectomy and fusion (ACDF) and multilevel laminoplasty and attempted to identify the radiological parameters affecting long-term clinical outcomes in CSM.

Methods

Of the 152 patients with multilevel CSM treated with three-level ACDF and multilevel laminoplasty, 42 had complete radiological parameters both before and 2 years after surgery (three-level ACDF, 22 patients; multilevel laminoplasty, 20 patients). Radiological parameters included spinal cord signal intensity (SI) changes on magnetic resonance imaging (MRI). Clinical outcomes including the Japanese Orthopaedic Association (JOA) score, neck disability index (NDI), Oswestry disability index (ODI), and 36-Item Short Form Health Survey score were measured.

Results

The ACDF group showed significant restoration of segmental lordosis postoperatively (preoperatively: 2.21°, 6 months: 8.37°, P=0.026), and segmental and cervical range of motion (ROM) was markedly reduced and well maintained until the final follow-up (preoperatively: 25.48°, 24 months: 4.35°, P<0.001; preoperatively: 41.71°, 24 months: 20.18°, P<0.001). The recovery rates of the JOA score were 42.85% and 57.40% in the ACDF and laminoplasty groups, respectively, although this difference was not statistically significant. Multivariate regression analysis demonstrated that signal change on MRI significantly affected the recovery rate (P=0.003). The visual analog scale (VAS) score and NDI decreased considerably only in the laminoplasty group, and device complications were confirmed only in the ACDF group (incidence rate =36.5%).

Conclusions

Multilevel laminoplasty showed better radiological and similar clinical outcomes. ACDF had more surgical complications. Spinal cord SI change on preoperative MRI was the independent risk factor for poor clinical outcomes. We recommend laminoplasty instead of three-level ACDF to treat multilevel CSM.

Surgical Strategies for Cervical Deformities Associated With Neuromuscular Disorders

Neuromuscular disorders (NMDs) are diseases involving the upper and lower motor neurons and muscles. In patients with NMDs, cervical spinal deformities are a very common issue; however, unlike thoracolumbar spinal deformities, few studies have investigated these disorders. The patients with NMDs have irregular spinal curvature caused by poor balance and poor coordination of their head, neck, and trunk. Particularly, cervical deformity occurs at younger age, and is known to show more rigid and severe curvature at high cervical levels. Muscular physiologic dynamic characteristics such as spasticity or dystonia combined with static structural factors such as curvature flexibility can result in deformity and often lead to traumatic spinal cord injury. In addition, postoperative complication rate is higher due to abnormal involuntary movement and muscle tone. Therefore, it is important to control abnormal involuntary movement perioperatively along with strong instrumentation for correction of deformity. Various methods such as botulinum toxin injection, physical therapy, muscle division technique, or intrathecal baclofen pump implant may help control abnormal involuntary movements and improve spinal stability. Surgical management for cervical deformities associated with NMDs requires a multidisciplinary effort and a customized strategy.