Outcome Measures and Variables Affecting Prognosis of Cervical Spondylotic Myelopathy: WFNS Spine Committee Recommendations

Is Upper Extremity or Lower Extremity Function More Important for Patient Satisfaction? An Analysis of 24-Month Outcomes from the QOD Cervical Spondylotic Myelopathy Cohort

STUDY DESIGN

Retrospective analysis of a prospective, multicenter registry.

OBJECTIVE

To assess whether upper or lower limb mJOA improvement more strongly associates with patient satisfaction after surgery for cervical spondylotic myelopathy (CSM).

SUMMARY OF BACKGROUND DATA

The modified Japanese Orthopaedic Association (mJOA) is commonly used to assess functional status in patients with CSM. Patients present with upper and/or lower extremity dysfunction, and it is unclear whether improvement in one and/or both symptoms drives postoperative patient satisfaction.

METHODS

This study utilizes the prospective Quality Outcomes Database (QOD) CSM data set. Clinical outcomes included mJOA and North American Spine Society (NASS) satisfaction. The upper limb mJOA score was defined as upper motor plus sensory mJOA, and the lower limb mJOA as lower motor plus sensory mJOA. Ordered logistic regression was used to determine whether upper or lower limb mJOA was more closely associated with NASS satisfaction, adjusting for other covariates.

RESULTS

Overall, 1141 patients were enrolled in the QOD CSM cohort. In all, 780 had both preoperative and 24-month mJOA scores, met inclusion criteria, and were included for analysis. The baseline mJOA was 12.1±2.7, and postoperatively, 85.6% would undergo surgery again (NASS 1 or 2, satisfied). Patients exhibited mean improvement in both upper (baseline:3.9±1.4 vs. 24 mo:5.0±1.1, P<0.001) and lower limb mJOA (baseline:3.9±1.4 vs. 24 mon:4.5±1.5, P<0.001); however, the 24-month change in the upper limb mJOA was greater (upper:1.1±1.6 vs. lower:0.6±1.6, P<0.001). Across 24-month NASS satisfaction, the baseline upper and lower limb mJOA scores were similar (pupper=0.28, plower=0.092). However, as satisfaction decreased, the 24-month change in upper and lower limb mJOA decreased as well (pupper<0.001, plower<0.001). Patients with NASS scores of 4 (lowest satisfaction) did not demonstrate significant differences from baseline in upper or lower limb mJOA (P>0.05). In ordered logistic regression, NASS satisfaction was independently associated with upper limb mJOA improvement (OR=0.81; 95% CI: 0.68-0.97; P=0.019) but not lower limb mJOA improvement (OR=0.84; 95% CI: 0.70-1.0; P=0.054).

CONCLUSIONS

As the magnitude of upper and lower mJOA improvement decreased postoperatively, so too did patient satisfaction with surgical intervention. Upper limb mJOA improvement was a significant independent predictor of patient satisfaction, whereas lower limb mJOA improvement was not. These findings may aid preoperative counseling, stratified by patients' upper and lower extremity treatment expectations.

LEVEL OF EVIDENCE

Level-III.

Four-level ACDF surgical series 2000-2022: a systematic review of clinical and radiological outcomes and complications

OBJECTIVE

The primary objective of this investigation is to systematically scrutinize extant surgical studies delineating Four-Level Anterior Cervical Discectomy and Fusion (4L ACDF), with a specific emphasis on elucidating reported surgical indications, clinical and radiological outcomes, fusion rates, lordosis correction, and the spectrum of complication rates.

METHODS

The literature review was conducted in adherence to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, employing the MEDLINE (PubMed), Embase, and Scopus databases. This analysis encompasses studies implementing the 4L ACDF procedure, with detailed extraction of pertinent data pertaining to surgical methodologies, types of employed interbody cages, clinical and radiological endpoints, rates of fusion, and the incidence of complications.

RESULTS

Among the 15 studies satisfying inclusion criteria, a marginal increment in the year 2022 (21.4%) was discerned, with a preponderance of study representation emanating from China (35.7%) and the United States (28.6%). 50% of the studies were single-surgeon studies. Concerning follow-up, studies exhibited variability, with 42.9% concentrating on periods of five years or less, and an equivalent proportion extending beyond this timeframe. Across the amalgamated cohort of 2457 patients, males constituted 51.6%, manifesting a mean age range of 52.2-61.3 years. Indications for surgery included radiculopathy (26.9%) and myelopathy (46.9%), with a predilection for involvement at C3-7 (24.9%). Meta-analysis yielded an overall complication rate of 16.258% (CI 95%: 14.823%-17.772%). Dysphagia (4.563%), haematoma (1.525%), hoarseness (0.205%), C5 palsy (0.176%) were the most prevalent complications of 4L ACDF. Fusion rates ranging from 41.3% to 94% were documented.

CONCLUSION

The 4L ACDF is commonly performed to address mylopathy and radiculopathy. While the surgery carries a complication rate of around 16%, its effectiveness in achieving bone fusion can vary considerably.

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.

Influence of Blood Pressure on Acute Cervical Spinal Cord Injury Without Fracture and Dislocation: Results From a Retrospective Analysis

OBJECTIVE

The objective of this study was to investigate the influence of blood pressure on the severity and functional recovery of patients with acute cervical spinal cord injury (SCI) without fracture and dislocation.

METHODS

A retrospective case control study analyzed the data of 40 patients admitted to our orthopedics department (Beijing Tiantan Hospital, Capital Medical University) from January 2013 to February 2021. They were diagnosed as acute cervical SCI without fracture and dislocation. Gender, age, height, weight, history of hypertension, postinjury American Spinal Injury Association grade, postinjury modified Japanese Orthopaedic Association (mJOA) score, postoperative mJOA score, 1-year follow-up mJOA score, preoperative mean arterial pressure (MAP), intramedullary T2 hyperintensity, and hyponatremia were collected. The patients were divided into groups and subgroups based on their history of hypertension and preoperative MAP. The effects of history of hypertension and preoperative MAP on the incidence of T2 hyperintensity, hyponatremia, the improvement rate of the postoperative mJOA and 1-year follow-up mJOA scores were analyzed.

RESULTS

Patients with history of hypertension had a lower incidence of intramedullary T2 hyperintensity than patients without history of hypertension (P < 0.05). Patients with history of hypertension and patients with a higher preoperative MAP had better neurological recovery at 1 year of follow-up (P < 0.05).

CONCLUSIONS

Blood pressure has great influence on acute cervical SCI without fracture and dislocation. Maintaining a higher preoperative MAP is advantageous for better recovery after SCI. Attention should be paid to the dynamic management of blood pressure to avoid the adverse effects of hypotension after SCI.

Development of the cervical myelopathy severity index: a new patient reported outcome measure to quantify impairments and functional limitations

BACKGROUND CONTEXT

Existing degenerative cervical myelopathy (DCM) severity scales have significant shortcomings, creating a strong impetus for the development of a practical measurement tool with sound psychometric properties.

PURPOSE

This work reports the item generation and reduction of the Cervical Myelopathy Severity Index (CMSI), a new DCM patient-reported outcome measure of symptoms and functional limitations.

DESIGN

Prospective observational study.

PATIENT SAMPLE

Adult DCM patients belonging to one of three distinct treatment groups: (1) observation cohort, (2) preoperative surgical cohort, (3) 6 to 12 months postoperative cohort.

OUTCOME MEASURES

Patient-reported outcome measure of symptoms and functional limitations.

METHODS

Item generation was performed using semi-structured patient focus groups emphasizing symptoms experienced and functional limitations. Readability was assessed through think-aloud patient interviews. Item reduction involved surveys of DCM patients with a spectrum of disease severity and board-certified spine surgeons experienced in the treatment of DCM. A priori criteria for item removal included: patient median importance/severity <2 (of 4), 30% or more no severity (response of zero), item severity correlations ≤ 0.80 (Spearman), item severity reliability (weighted kappa <0.60) based on a 2-week interval and clinician median importance <2 with retention of items with very high clinical importance.

RESULTS

There were 42 items generated from a combination of specialist input and patient focus groups. Items captured sensorimotor symptoms and limitations related to upper and lower extremities as well as sphincter dysfunction. Ninety-eight patients (43, 30, 25 observation, pre- and postsurgery respectively) and 51 surgeons completed the assessment. Twenty-three items remained after application of median importance and severity thresholds and weighted kappa cutoffs. After elimination of highly correlated (>0.80) items and combining two similar items, the final CMSI questionnaire list included 14 items.

CONCLUSIONS

The CMSI is a new DCM patient-reported clinical measurement tool developed using patient and clinician input to inform item generation and reduction. Future work will evaluate the reliability, validity, and responsiveness of the CMSI in relation to existing myelopathy measurement indices.

Classification and prognostic factors of patients with cervical spondylotic myelopathy after surgical treatment: a cluster analysis

Identifying potential prognostic factors of CSM patients could improve doctors' clinical decision-making ability. The study retrospectively collected the baseline data of population characteristics, clinical symptoms, physical examination, neurological function and quality of life scores of patients with CSM based on the clinical big data research platform. The modified Japanese Orthopedic Association (mJOA) score and SF-36 score from the short-term follow-up data were entered into the cluster analysis to characterize postoperative residual symptoms and quality of life. Four clusters were yielded representing different patterns of residual symptoms and quality of patients' life. Patients in cluster 2 (mJOA RR 55.8%) and cluster 4 (mJOA RR 55.8%) were substantially improved and had better quality of life. The influencing factors for the better prognosis of patients in cluster 2 were young age (50.1 ± 11.8), low incidence of disabling claudication (5.0%) and pathological signs (63.0%), and good preoperative SF36-physiological function score (73.1 ± 24.0) and mJOA socre (13.7 ± 2.8); and in cluster 4 the main influencing factor was low incidence of neck and shoulder pain (11.7%). We preliminarily verified the reliability of the clustering results with the long-term follow-up data and identified the preoperative features that were helpful to predict the prognosis of the patients. This study provided reference and research basis for further study with a larger sample data, extracting more patient features, selecting more follow-up nodes, and improving clustering algorithm.

Diagnostic and prognostic significance of preoperative evoked potential tests in degenerative cervical myelopathy

BACKGROUND CONTEXT

Decompression surgery is a treatment option for patients with degenerative cervical myelopathy (DCM). Surgical decisions primarily depend on clinical symptoms and radiological examinations. The diagnostic and prognostic significance of evoked potential tests for surgical outcomes in patients with DCM has not been thoroughly examined.

PURPOSE

To identify the diagnostic and prognostic significance of preoperative evoked potential tests in patients with DCM who underwent decompression surgery.

STUDY DESIGN

This was a retrospective observational study.

PATIENT SAMPLE

One hundred two consecutive patients who underwent evoked potential tests and surgical treatment between January 2016 and December 2020 in a single spine center and had a minimum follow-up of 6 months.

OUTCOME MEASURES

Japanese Orthopedic Association (JOA) scores obtained preoperatively and 6 months after surgery.

METHODS

This study evaluated the preoperative central motor conduction time (CMCT), somatosensory evoked potentials, and Japanese Orthopedic Association (JOA) scores obtained preoperatively and 6 months after surgery.

RESULTS

Abnormal CMCT findings were observed in 94 patients (92.2%). Abnormal somatosensory evoked potentials were observed in 77 patients (75.5%). There was a statistically significant correlation between preoperative JOA score and abductor pollicis brevis (APB)-CMCT (r=-0.546, p=.001), tibialis anterior (TA)-CMCT (r=-0.517, p<.001), median nerve (MN)-SSEP (r=-0.353, p=.001), and tibial nerve (TN)-SSEP (r=-0.349, p=.003). There were significant differences in recovery rates associated with diabetes mellitus (DM), preoperative severity of myelopathy, TA-CMCT, MN-SSEP, and TN-SSEP. Stepwise multiple regression analysis showed that the major factors affecting the clinical outcomes were TN-SSEP (β=0.327, p=.004), preoperative JOA score (β=0.278, p=.012), and DM (β=0.241, p=.025).

CONCLUSIONS

Evoked potential testing is a functional diagnostic tool that can indicate the severity of myelopathic symptoms in patients with DCM. Additionally, preoperative TN-SSEP may have significant prognostic value in predicting postoperative clinical outcomes. Thus, preoperative evoked potential tests could be helpful for determining suitable surgical treatment candidates and forecasting postoperative prognosis.

Clinical outcome of surgical management of mild cervical compressive myelopathy based on minimum clinically important difference

BACKGROUND CONTEXT

Cervical compressive myelopathy (CCM), caused by cervical spondylosis (cervical spondylotic myelopathy [CSM]) or ossification of the posterior longitudinal ligament (OPLL), is a common neurological disorder in the elderly. For moderate/severe CCM, surgical management has been the first-line therapeutic option. Recently, surgical management is also recommended for mild CCM, and a few studies have reported the surgical outcome for this clinical population. Nonetheless, the present knowledge is insufficient to determine the specific surgical outcome of mild CCM.

PURPOSE

To examine the surgical outcomes of mild CCM while considering the minimum clinically important difference (MCID).

STUDY DESIGN

Retrospective study.

PATIENT SAMPLE

Patients who underwent subaxial cervical surgery for CCM caused by CSM and OPLL between 2013 and 2022 were enrolled.

OUTCOME MEASURES

The Japanese Orthopedic Association score (JOA score) was employed as the clinical outcomes. Based on previous reports, the JOA score threshold to determine mild myelopathic symptoms was set at ≥14.5 points, and the MCID of the JOA score for mild CCM was set at 1 point.

METHODS

The patients with a JOA score of ≥14.5 points at baseline were stratified into the mild CCM and were examined while considering the MCID. The mild CCM cohort was dichotomized into the improvement group, including the patients with an achieved MCID (JOA score ≥1 point) or with a JOA score of 17 points (full mark) at 1 year postoperatively, and the nonimprovement group, including the others. Demographics, symptomatology, radiographic findings, and surgical procedure were compared between the two groups and studied using the receiver operating characteristic (ROC) curve.

RESULTS

Of 335 patients with CCM, 43 were stratified into the mild CCM cohort (mean age, 58.5 years; 62.8% male). Among them, 25 (58.1 %) patients were assigned to the improvement group and 18 (41.9 %) were assigned to the nonimprovement group. The improvement group was significantly younger than the nonimprovement group; however, other variables did not significantly differ. ROC curve analysis showed that the optimal cutoff point of the patient's age to discriminate between the improvement and nonimprovement groups was 58 years with an area under the curve of 0.702 (p=.015).

CONCLUSIONS

In the present study, the majority of patients with mild CCM experienced improvement reaching the MCID of JOA score at 1 year postoperatively. The present study suggests that for younger patients with mild CCM, especially those aged below 58 years, subjective neurological recovery is more likely to be obtained. Meanwhile, the surgery takes on a more prophylactic significance to halt disease progression for older patients. The results of this study can help in the decision-making process for this clinical population.

Spinal Cord Signal Intensity Predicts Functional Outcomes in the Operative Management of Degenerative Cervical Myelopathy

STUDY DESIGN

Prospective single institutional cohort study on degenerative cervical myelopathy (DCM) from 2009 to 2022.

OBJECTIVE

This study aims to assess the relationship among preoperative spinal cord signal change, postoperative signal change evolution, and functional outcome in patients undergoing surgery for DCM.

SUMMARY OF BACKGROUND DATA

There is conflicting evidence on whether spinal cord signal intensity influences functional outcomes in patients with DCM.

PATIENTS AND METHODS

This prospective study investigated 104 patients with DCM that underwent both preoperative and routine postoperative cervical spine magnetic resonance imaging (MRI) as part of a research protocol. Signal intensity/grade, modified Japanese Orthopedic Association (mJOA) scores, signal resolution, and patient demographics were assessed.

RESULTS

Sixty-eight of the subjects were found to have abnormal T2 spinal cord signal intensity changes on their preoperative MRI. The total mean preoperative mJOA score was 13.6, increasing postoperatively to 16 (P < 0.001). The presence or absence of preoperative spinal cord signal change was not associated with the change in mJOA score or neurological recovery rate after surgery. Of the 68 patients with preoperative T2 signal change, 36 were found to have an improvement in the T2-weighted signal grade after surgery and 32 had no change in postoperative signal grade. The mean improvement in mJOA score (3.7) and neurological recovery rate (70.3%) was significantly higher in the patients with preoperative signal change whose postoperative MRI signal change grade improved by at least one point compared with those that did not (2.0, 50.5%), (P < 0.001, P < 0.003).

CONCLUSIONS

The presence of preoperative T2-weighted signal change was associated with lower preoperative mJOA scores, but no change in mJOA after surgery or postoperative neurological recovery rate. However, improvement in T2-weighted spinal cord signal grade on postoperative MRI was significantly associated with a degree of neurological improvement after surgery.

Investigation of the Efficacy of Bilateral Osteoligamentous Decompression via Hemilaminectomy in Cervical Spondylotic Myelopathy: A Clinical Study

OBJECTIVE

Cervical stability may deteriorate and kyphotic spinal deformities may develop in cervical spondylotic myelopathy (CSM) after laminectomy or laminoplasty. This study aimed to investigate the therapeutic efficacy of the "bilateral osteoligamentous decompression via unilateral hemilaminectomy approach (UHBOLD)" technique in CSM patients.

METHODS

The study included 34 adult patients who underwent UHBOLD surgery for CSM between 2016 and 2022. A record was made for all patients of age, gender, number of operated levels, preoperative and postoperative long-term follow-up VAS scores, Nurick grade values and mJOA scores, kyphosis angles measured on X-ray, and spinal canal areas measured on T2-weighted MR axial images.

RESULTS

Preoperative VAS scores of the patients were 6 (4-9), Nurick grade values were 3 (2-5), mJOA scores were 10.50 ± 3.42, kyphosis angles were -13.34 ± 13.69° and spinal canal areas were 87.11 ± 28.30 mm2. In postoperative long-term follow-up of these patients, VAS scores were 2 (1-5), Nurick grade values were 1 (0-5), mJOA scores were 13.94 ± 3.09, kyphosis angles were -15.07 ± 12.78° and spinal canal areas were 149.65 ± 42.57 mm2. A statistically significant difference was determined between the preoperative and the postoperative long-term follow-up VAS scores, Nurick grade values, mJOA scores, and spinal canal areas (P < 0.001). Kyphosis angles were not different (P = 0.198), and no instability was observed in any patient in long-term follow-up.

CONCLUSIONS

The UHBOLD technique performed in multilevel CSM patients did not cause any change in cervical lordosis angle in long-term follow-up, did not cause cervical kyphotic deformity or cervical instability, and significantly improved Nurick grade values, and VAS and mJOA scores.

Cervical muscle morphometry and composition demonstrate prognostic value in degenerative cervical myelopathy outcomes

Objectives

This study aimed to examine whether preoperative cervical muscle size, composition, and asymmetry from magnetic resonance imaging (MRI) can predict post-operative outcomes in patients with degenerative cervical myelopathy (DCM).

Methods

A total of 171 patients with DCM were included. Relative total cross-sectional area (RCSA), functional CSA (fat-free area, FCSA), ratio of FCSA/CSA (fatty infiltration) and asymmetry of the multifidus (MF) and semispinalis cervicis (SCer) together (MF + SCer), and cervical muscle as a group (MF, SCer, semispinalis capitis, and splenius capitis) were obtained from T2-weighted axial MR images at the mid-disk, at the level of maximum cord compression and the level below. Univariate and multivariate linear regression analyses were used to assess the relationship between baseline cervical muscle measurements of interest with the modified Japanese Orthopedic Association (mJOA), Nurick Classification, Neck Disability Index (NDI), and SF-36 health survey at 6-month and 12-month post-surgery.

Results

Lower RCSA of MF + SCer, less CSA MF + SCer asymmetry and greater FCSA/CSA for the cervical muscle group (e.g., less fatty infiltration), and younger age were significant predictors of higher mJOA scores (e.g., less disability) at 6-month and 12-month post-surgery (all p < 0.05). Greater CSA asymmetry in MF + SCer and lower FCSA/CSA (e.g., more fatty infiltration) for the cervical muscle group were significant predictors of higher Nurick scores (e.g., more disability) at 6-month and 12-month post-surgery (all p < 0.05). Lower FCSA MF + Scer asymmetry, lower FCSA/CSA asymmetry of the muscle group, and greater RCSA MF + SCer were significant predictors of higher NDI scores at 6-month and 12-month post-surgery. Finally, greater FCSA/CSA asymmetry of the MF + SCer, greater FCSA asymmetry of the muscle group, greater RCSA of the muscle group, and greater CSA asymmetry of MF + SCer were significant predictors of lower post-operative SF-36 scores at 6- and 12-month post-surgery.

Conclusion

Our result suggested that cervical paraspinal muscle morphology, specifically greater asymmetry, and fatty infiltration may be important predictors of functional recovery and post-surgical outcomes in patients with DCM.

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.

Utility of MRI in Quantifying Tissue Injury in Cervical Spondylotic Myelopathy

Cervical spondylotic myelopathy (CSM) is a progressive disease that worsens over time if untreated. However, the rate of progression can vary among individuals and may be influenced by various factors, such as the age of the patients, underlying conditions, and the severity and location of the spinal cord compression. Early diagnosis and prompt treatment can help slow the progression of CSM and improve symptoms. There has been an increased use of magnetic resonance imaging (MRI) methods in diagnosing and managing CSM. MRI methods provide detailed images and quantitative structural and functional data of the cervical spinal cord and brain, allowing for an accurate evaluation of the extent and location of tissue injury. This review aims to provide an understanding of the use of MRI methods in interrogating functional and structural changes in the central nervous system in CSM. Further, we identified several challenges hindering the clinical utility of these neuroimaging methods.

A Comparison Between Somatosensory Evoked Potentials and Spine MRI in the Diagnosis of Non-compressive Myelopathy: Which Is More Accurate?

INTRODUCTION

Non-compressive myelopathy is a neurological disorder due to pathological processes affecting the spinal cord in the absence of clinical and radiological evidence of spinal cord compression. Two commonly used diagnostic tools for non-compressive myelopathy are somatosensory evoked potentials (SSEPs) and magnetic resonance imaging (MRI). SSEPs are a neurophysiological tool used to assess the functional integrity of the spinal cord. MRI, on the other hand, is the mainstay imaging modality used for identifying compressive lesions and other structural abnormalities in the spinal cord. The aim of this study was to test the diagnostic accuracy of SSEPs versus spine MRI in the diagnosis and assessment of the severity of non-compressive myelopathy using the Modified Japanese Orthopaedic Association (mJOA) clinical severity score.

METHODS

Our study included 63 subjects. Whole spine MRI and SSEPs (median and tibial SSEP bilaterally) were done for all subjects; their results were compared according to their relation to the mJOA score and classified into mild, moderate, and severe. The control group was examined to establish normative data for SSEP results and compared with cases. Blood investigations such as complete blood count, thyroid function test, A1C, HIV tests, venereal disease research laboratory test, erythrocyte sedimentation rate, C-reactive protein, and antinuclear antibody tests were done. Blood tests for vitamin B12 levels were done for patients who were suspected of sub-acute combined degeneration of the spinal cord; cerebrospinal fluid (CSF) analysis was done for patients suspected of multiple sclerosis (MS), acute transverse myelitis (ATM), or other inflammatory/infectious diseases. CSF was analyzed for cell count, cytology, protein, and oligoclonal bands (if indicated).

RESULTS

No mild categories were registered in this study; 30% of patients were moderate and 70% were severe. Causes for non-compressive myelopathy in this study were hereditary degenerative ataxias in 12 (38.71%), ATM in 8 (25.81%), and MS in 5 (16.13%); other causes included vitamin B12 deficiency in 2 (6.45%), ischemia in 2 (6.45%), and an unknown cause in 2 (6.45%). SSEPs showed abnormal results in all patients (31; 100%) whereas MRI showed abnormality in only seven patients (22.6%). SSEP sensitivity for detecting severe cases was around 63.6% while that for MRI was 27.3%.

CONCLUSION

The study concluded that SSEPs were more reliable for the detection of non-compressive myelopathies rather than MRI and correlated better with clinical severity. Performing SSEPs is recommended for all patients with non-compressive myelopathy, especially those with negative imaging.

Neurological Survivorship Following Surgery for Degenerative Cervical Myelopathy: A Longitudinal Study on 195 Patients

BACKGROUND

Long-term data on postoperative neurological survivorship for patients with degenerative cervical myelopathy (DCM) undergoing decompressive surgery are limited. The purposes of this study were to assess neurological survivorship after primary decompressive surgery for DCM and to identify predictors for postoperative deterioration.

METHODS

A longitudinal clinical data set containing surgical details, medical comorbidities, and radiographic features was assembled for 195 patients who underwent a surgical procedure for DCM between 1999 and 2020, with a mean period of observation of 75.9 months. Kaplan-Meier curves were plotted, and a log-rank test was performed for the univariate analysis of factors related to neurological failure. Lasso regression facilitated the variable selection in the Cox proportional hazards model for multivariate analysis.

RESULTS

The overall neurological survivorship was 89.3% at 5 years and 77.3% at 10 years. Cox multivariate analysis following lasso regression identified elevated hazard ratios (HRs) for suture laminoplasty (HR, 4.76; p < 0.001), renal failure (HR, 4.43; p = 0.013), T2 hyperintensity (HR, 3.34; p = 0.05), and ossification of the posterior longitudinal ligament (OPLL) (HR, 2.32; p = 0.032). Subgroup analysis among subjects with OPLL demonstrated that the neurological failure rate was significantly higher in the absence of fusion (77.8% compared with 26.3%; p = 0.019).

CONCLUSIONS

Overall, patients who underwent a surgical procedure for DCM exhibited an extended period with neurological improvement. Cervical fusion was indicated in OPLL to reduce neurological failure. Our findings on predictors for early deterioration facilitate case selection, prognostication, and counseling as the volume of primary cervical spine surgeries and reoperations increases globally.

LEVEL OF EVIDENCE

Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Clinically meaningful improvement in disabilities of arm, shoulder, and hand (DASH) following cervical spine surgery

BACKGROUND CONTEXT

Patients with cervical spine disease suffer from upper limb disability. At present, no clinical benchmarks exist for clinically meaningful change in the upper limb function following cervical spine surgery.

PURPOSE

Primary: to establish clinically meaningful metrics; the minimal clinically important difference (MCID) and substantial clinical benefit (SCB) of upper limb functional improvement in patients following cervical spine surgery. Secondary: to identify the prognostic factors of MCID and SCB of upper limb function following cervical spine surgery.

STUDY DESIGN

Retrospective cohort study.

PATIENT SAMPLE

Adult patients ≥18 years of age who underwent cervical spine surgery from 2012 to 2016.

OUTCOME MEASURES

Patient-reported outcomes: Neck disability index (NDI) and Disabilities of Arm, Shoulder, and Hand (DASH).

METHODS

MCID was defined as minimal improvement and SCB as substantial improvement in the DASH score at last follow-up. The anchor-based methods (ROC analyses) defined optimal MCID and SCB thresholds with area under curve (AUC) in discriminating improved vs. non-improved patients. The MCID was also calculated by distribution-based methods: half standard-deviation (0.5-SD) and standard error of the mean (SEM) method. A multivariable logistic regression evaluated the impact of baseline factors in achieving the MCID and SCB in DASH following cervical spine surgery.

RESULTS

Between 2012 and 2016, 1,046 patients with average age of 57±11.3 years, 53% males, underwent cervical spine surgery. Using the ROC analysis, the threshold for MCID was -8 points with AUC of 0.73 (95% CI: 0.67-0.79) and the SCB was -18 points with AUC of 0.88 (95% confidence interval [CI]: 0.85-0.91). The MCID was -11 points by 0.5-SD and -12 points by SEM-method. On multivariable analysis, patients with myelopathy had lower odds of achieving MCID and SCB, whereas older patients and those with ≥6 months duration of symptoms had lower odds of achieving DASH MCID and SCB respectively.

CONCLUSIONS

In patients undergoing cervical spine surgery, MCID of -8 points and SCB of -18 points in DASH improvement may be considered clinically significant. These metrics may enable evaluation of minimal and substantial improvement in the upper extremity function following cervical spine surgery.

Diffusion Basis Spectrum Imaging Provides Insights Into Cervical Spondylotic Myelopathy Pathology

BACKGROUND

Diffusion basis spectrum imaging (DBSI) is a noninvasive quantitative imaging modality that may improve understanding of cervical spondylotic myelopathy (CSM) pathology through detailed evaluations of spinal cord microstructural compartments.

OBJECTIVE

To determine the utility of DBSI as a biomarker of CSM disease severity.

METHODS

A single-center prospective cohort study enrolled 50 patients with CSM and 20 controls from 2018 to 2020. All patients underwent clinical evaluation and diffusion-weighted MRI, followed by diffusion tensor imaging and DBSI analyses. Diffusion-weighted MRI metrics assessed white matter integrity by fractional anisotropy, axial diffusivity, radial diffusivity, and fiber fraction. In addition, DBSI further evaluates extra-axonal changes by isotropic restricted and nonrestricted fraction. Including an intra-axonal diffusion compartment, DBSI improves estimations of axonal injury through intra-axonal axial diffusivity. Patients were categorized into mild, moderate, and severe CSM using modified Japanese Orthopedic Association classifications. Imaging parameters were compared among patient groups using independent samples t tests and ANOVA.

RESULTS

Twenty controls, 27 mild (modified Japanese Orthopedic Association 15-17), 12 moderate (12-14), and 11 severe (0-11) patients with CSM were enrolled. Diffusion tensor imaging and DBSI fractional anisotropy, axial diffusivity, and radial diffusivity were significantly different between control and patients with CSM ( P < .05). DBSI fiber fraction, restricted fraction, and nonrestricted fraction were significantly different between groups ( P < .01). DBSI intra-axonal axial diffusivity was lower in mild compared with moderate (mean difference [95% CI]: 1.1 [0.3-2.1], P < .01) and severe (1.9 [1.3-2.4], P < .001) CSM.

CONCLUSION

DBSI offers granular data on white matter tract integrity in CSM that provide novel insights into disease pathology, supporting its potential utility as a biomarker of CSM disease progression.

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.

Predicting postoperative recovery in cervical spondylotic myelopathy: construction and interpretation of T2*-weighted radiomic-based extra trees models

OBJECTIVES

Conventional MRI may not be ideal for predicting cervical spondylotic myelopathy (CSM) prognosis. In this study, we used radiomics in predicting postoperative recovery in CSM. We aimed to develop and validate radiomic feature-based extra trees models.

METHODS

There were 151 patients with CSM who underwent preoperative T₂-/ T₂^*-weighted imaging (WI) and surgery. They were divided into good/poor outcome groups based on the recovery rate. Datasets from multiple scanners were randomised into training and internal validation sets, while the dataset from an independent scanner was used for external validation. Radiomic features were extracted from the transverse spinal cord at the maximum compressed level. Threshold selection algorithm, collinearity removal, and tree-based feature selection were applied sequentially in the training set to obtain the optimal radiomic features. The classification of intramedullary increased signal on T₂/T₂^*WI and compression ratio of the spinal cord on T₂^*WI were selected as the conventional MRI features. Clinical features were age, preoperative mJOA, and symptom duration. Four models were constructed: radiological, radiomic, clinical-radiological, and clinical-radiomic. An AUC significantly > 0.5 was considered meaningful predictive performance based on the DeLong test. The mean decrease in impurity was used to measure feature importance. p < 0.05 was considered statistically significant.

RESULTS

On internal and external validations, AUCs of the radiomic and clinical-radiomic models, and radiological and clinical-radiological models ranged from 0.71 to 0.81 (significantly > 0.5) and 0.40 to 0.55, respectively. Wavelet-LL first-order variance was the most important feature in the radiomic model.

CONCLUSION

Radiomic features, especially wavelet-LL first-order variance, contribute to meaningful predictive models for CSM prognosis.

KEY POINTS

• Conventional MRI features may not be ideal in predicting prognosis. • Radiomics provides greater predictive efficiency in the recovery from cervical spondylotic myelopathy.

Increased signal intensity on postoperative T2-weighted axial images in cervical spondylotic myelopathy: Patterns of changes and associated impact on outcomes

Although T2-weighted axial magnetic resonance imaging (MRI) has strength in demonstrating morphologic characteristics of the spinal cord in cervical spondylotic myelopathy (CSM), no study has investigated postoperative changes. We aimed to assess postoperative changes on T2-weighted axial MRI using the classification system based on axial imaging in cervical compressive myelopathy (Ax-CCM) and associated impact on outcome in CSM. In total, 250 patients with CSM who underwent decompressive surgery with preoperative and postoperative MRI were included. At first, we investigated the presence of increased signal intensity (SI) in cervical spinal cord on T2-weighted sagittal images. Next, the increased SI was assessed using Ax-CCM on T2weighted axial images. The classifications were type 0, no-signal abnormality; single-level type 1, diffuse; single-level type 2, fuzzy focal; single-level type 3, discrete focal; and two-level. The recovery rates (RRs) of modified Japanese Orthopaedic Association (mJOA) score were evaluated from 5 to 10 months postoperatively. Eighty-seven patients (34.8%) exhibited postoperative changes. Most of postoperative changes were in single-level type 1 and 2. Patterns of changes were resolution, reduced extent, or transition to discrete margin. The most common pattern was resolution in type 1 (23.9%) and transition to discrete margin in type 2 (46.5%). In each group, resolution showed the best RR, but insignificantly (p > 0.05).

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.

Fusion rates for conservative and surgical management of type II odontoid fractures and its impact

BACKGROUND

Type II odontoid fractures are known to have low fusion rates following conservative management with a hard collar. However, most patients are elderly with comorbidities and are not fit for surgery. The present study identified the rates of bony fusion, complications, and clinical outcomes following conservative management of type II odontoid fractures.

METHODS

We included consecutive patients referred with a suspected odontoid fracture to a Major Trauma Centre in the UK between March 2015 and December 2017. Data including patient demographics, fracture management, complications and outcomes. Bony fusion was assessed by two neurosurgeons and one neuroradiologists. Results were analysed with simple statistics and chi-squared test.

RESULTS

102 patients were included in the study (mean age = 80.4 ± 15.3). 10 (9.8%) were managed surgically and 92 (90.2%) were managed conservatively with a hard collar, for a mean of 87 days. Patients were followed up for a mean of 28.1 months (range 1-855 days) until discharge. 37% developed collar complications, namely pain, stiffness and non-tolerance. Bony union was achieved in 37.3% of patients treated with a hard collar (versus 80% in the surgical group, p = 0.0096). Increasing age was an independent risk factor for non-union (p < 0.001). Of the patients without bony union, none reported symptoms, and 90% were discharged without a collar.

CONCLUSION

The management of type II odontoid fractures are difficult in an elderly, co-morbid population. With conservative management fusion rates are low, and collar complications are not insignificant. However, outcomes are good regardless of union.

Nine-segment laminectomy is safe for the resection of a schwannoma extending from C-2 to T-3: a rare case report

Cervical spine schwannoma, which is long and entirely intracanal, is rare to be found. Its rarity and atypical feature leads to difficulty in diagnosing and managing cases because of the scarcity of available literature. The surgical removal of this type of schwannomas via multisegment laminectomy is a great challenge because of various risks of postoperative complications. This report describes cervical spine schwannoma that was initially was not suspected as schwannoma and was subject to surgical removal via nine-segment laminectomy. In one year after surgery, motor function returned to normal strength, no new neurological deficits occurred, and no kyphotic deformity, which is a common complication of multisegment laminectomy.

Degenerative Cervical Myelopathy: Review of Surgical Outcome Predictors and Need for Multimodal Approach

Degenerative cervical myelopathy is the most common cause of spinal cord injury in the elderly population in the developed world, and it significantly affects the quality of life of patients and their caregivers. Surgery remains the only treatment option able to halt disease progression and provide neurological recovery for most patients. Although it has remained challenging to predict exactly who will experience improvement after surgery, increasingly it has been shown that clinical, imaging, and electrophysiological factors can predict, with relatively good capacity, those more likely to benefit. Clinically, the baseline neurological impairment appears to be strongly related to the outcome, and the magnetic resonance imaging findings of T1-weighted hypointensity and the length of T2-weighted hyperintensity appear to be the most prognostic. In this context, electrophysiology findings (both motor and sensory evoked potentials) have shown some predictive capacity. However, large studies are lacking. Although multivariate models have been conducted using clinical and magnetic resonance imaging data, no multimodal prediction models are available that encompass the predictive capacity of clinical, imaging, and electrophysiological data. In the present review, we examined the rationale for clinical, imaging, and electrophysiological usage in clinical practice and discussed a model of multimodal assessment for the management of degenerative cervical myelopathy.

Internet of Things, Digital Biomarker, and Artificial Intelligence in Spine: Current and Future Perspectives

Recent interest in medical artificial intelligence (AI) has increased with onset of the fourth industrial revolution. Real-time monitoring of patients is an important research area of medical AI. The medical AI is very closely related to the Internet of Things (IoT), a core element of the fourth industrial revolution. Attempts to diagnose and treat patients using IoT have been already applied to patients with chronic disease such as hypertension and arrhythmia. However, in the spine, research on IoT and digital biomarkers are still in the early stages. The digital biomarker obtained by IoT devices is objective and could represent real-time, real-world, and abundant data. Based on its characteristics, IoT and digital biomarkers can also be useful in the spine. Currently, research on real-time monitoring of physical activity or spinal posture is ongoing. Therefore, the authors introduce the basic concepts of IoT and digital biomarkers, their relationship to AI, and recent trends. Current and future perspectives of IoT and digital biomarker in spine are also discussed. In the future, it is expected that IoT, digital biomarkers, and AI will lead to a paradigm shift in the diagnosis and treatment of spinal diseases.