Congenital Cervical Spine Stenosis in a Multicenter Global Cohort of Patients With Degenerative Cervical Myelopathy: An Ambispective Report Based on a Magnetic Resonance Imaging Diagnostic Criterion

Gait Function Outcomes and Prognostic Factors Following Laminoplasty for Cervical Spondylotic Myelopathy in Patients Who Were Nonambulatory But Were Ambulatory Before Symptom Progression

STUDY DESIGN

Retrospective study.

OBJECTIVE

To investigate gait function outcomes following laminoplasty and related prognostic factors in nonambulatory patients with cervical spondylotic myelopathy (CSM).

SUMMARY OF BACKGROUND DATA

The extent to which gait functional improvement can be expected after surgery in nonambulatory patients with CSM remains poorly understood.

METHODS

We included 83 nonambulatory patients (48 men and 35 women; mean age: 77.2 y) with a baseline Japanese Orthopedic Association motor function subscore of the lower extremity (JOA-LE) of 0 or 1. JOA-LE and total scores assessed clinical outcomes preoperatively and at 1 year postoperatively. Multivariate logistic regression analysis was performed to identify predictors of favorable gait function outcomes (achievement of postoperative JOA-LE ≥2).

RESULTS

Overall, 34 patients (41.0%) had favorable outcomes and 49 had unfavorable outcomes, with postoperative JOA-LE ≤1. Significantly more patients with baseline JOA-LE of 1 achieved favorable outcomes than those with baseline JOA-LE of 0 (52.9% vs. 21.9%, P<0.001). The mean JOA recovery rate was 37.4±23.7%, and the minimum clinically important difference in success rate was 26.5%. Patients with favorable outcomes had a significantly lower body mass index, shorter symptom duration, better baseline JOA-LE, and less frequent grade 2 increased intramedullary signal intensity on magnetic resonance imaging than those with unfavorable outcomes. Favorable outcomes were significantly and independently predicted by shorter symptom duration, with an optimal threshold of 3 months, and better baseline JOA-LE. Only 41.2% of patients with a baseline JOA-LE of 0 achieved a favorable outcome, despite them undergoing surgery within 3 months of symptom onset.

CONCLUSIONS

Laminoplasty may improve gait function and alleviate myelopathy in nonambulatory patients with CSM. Surgical intervention within 3 months of symptom exacerbation is recommended to mitigate walking disability; however, it presents limitations and challenges, particularly in patients who could not ambulate, even with support, before surgery.

LEVEL OF EVIDENCE

Level III.

Predictive role of preoperative parameters in LAMP outcomes for myelopathy caused by COPLL

OBJECTIVES

This study aims to assess the predictive value of preoperative parameters on recovery outcomes in patients with myelopathy caused by cervical ossification of the posterior longitudinal ligament (COPLL) undergoing laminoplasty (LAMP).

METHODS

A retrospective analysis was performed on myelopathy patients caused by COPLL who underwent LAMP between 2017 and 2020. Preoperative variables, including basic epidemiological characteristics, comorbidities, functional scores, K-line-related parameters, Torg-Pavlov ratio, maximal SCOR and COPLL shape, were analyzed for their predictive influence on postoperative outcomes in cervical spine function, upper and lower extremity function, bladder function, and quality of life (QOL). Binary logistic regression model analyses were used to evaluate predictive accuracy.

RESULTS

A total of 84 patients were included in the study. Preoperative parameters were significant predictors of postoperative improvement following LAMP surgery for myelopathy caused by COPLL. K-line-related factors, including K-line (-) (AUC = 0.80) and K-line on sagittal T1WI (-) (AUC = 0.76), were important predictors of cervical spine function improvement. Preoperative QOL scores (AUC = 0.78) also played a significant role in predicting cervical spine function improvement. For upper extremity function, preoperative upper extremity scores were a key predictor (AUC = 0.79), while C4-C6 K-line (-) (AUC = 0.81) was also a relevant factor. Similarly, preoperative lower extremity scores were crucial for predicting lower extremity function improvement (AUC = 0.85), and preoperative QOL scores were significant predictors of QOL improvement (AUC = 0.78). Other parameters, such as the Torg-Pavlov ratio, maximal SCOR, and the shape of COPLL, provided supplementary predictive value, though their influence was secondary to JOACMEQ scores and K-line parameters. Bladder function showed minimal postoperative improvement, with preoperative bladder status and the Torg-Pavlov ratio at C5 being the primary predictors for bladder improvement. Overall, preoperative K-line findings, JOACMEQ scores, and spinal canal measurements provided valuable guidance for postoperative expectations and surgical planning.

CONCLUSIONS

Preoperative K-line parameters and JOACMEQ scores are robust predictors of functional recovery in myelopathy patients caused by COPLL undergoing LAMP. While Torg-Pavlov ratio, maximal SCOR, and the shape of COPLL offer additional predictive value for overall recovery, they remain useful for preoperative surgical planning. These findings emphasize the importance of comprehensive preoperative assessment to optimize outcomes.

The Prevalence of Congenital Cervical Stenosis Differs based on Race

BACKGROUND

Congenital cervical stenosis (CCS) is a rare condition involving a narrowed spinal canal due to developmental anomalies. CCS heightens the risk of neurologic deficits and acute spinal cord injury post-trauma, influencing return-to-play decisions for contact athletes. Additionally, CCS patients are prone to cervical myelopathy as degenerative changes progress with age. Limited evidence-based literature exists addressing the epidemiology of CCS, including the effects of race.

PURPOSE

To investigate the anatomical differences and prevalence of CCS as it pertains to race and ethnicity.

STUDY DESIGN

Single center retrospective cross-sectional study.

PATIENT SAMPLE

A total of 343 patients with cervicalgia between the years of 1999-2023.

OUTCOME MEASURES

Radiographic measurements of anatomical parameters were collected and CCS was defined as a sagittal canal diameter (SCD) of less than 10 mm at 2 or more vertebral levels (C3-7) at the pedicle.

METHODS

We screened 5395 cervical MRIs from a single institution. Exclusion criteria included patients under 18 and over 50 years, prior cervical spine surgery, congenital fusions, spinal malignancy, or active smoking history. For each patient, axial measurements were taken at each level, including coronal vertebral body length, anteroposterior vertebral body length, pedicle width, pedicle length, laminar length, anteroposterior lateral mass length, posterior canal distance, apex-to-vertebral body, lamina-disc angle (LDA), lamina-pedicle angle, and anteroposterior spinal cord diameter.

RESULTS

CCS prevalence varied significantly among ethnic groups; Black (39.3%), Asian (33.6%), and Hispanic (22%) patients demonstrated significantly higher CCS rates than White patients (7.5%) [x2 (3, N=343) = 30.04, p <0.05)]. Blacks and Asians showed consistently smaller SCDs at all pedicle levels compared to Whites, who had the largest SCDs overall (p<0.001). Average SCDs were 11.4 mm (White), 10.4 mm (Black), 10.5 mm (Asian), and 11 mm (Hispanic). Additionally, LDAs were larger in Asians, Blacks, and Hispanics compared to Whites, leading to a significantly decreased cross-sectional canal area (p<0.001).

CONCLUSIONS

Our study indicates a statistically significant correlation between race/ethnicity and CCS prevalence. Black and Asian patients had the highest CCS rates, smallest SCDs, and largest LDAs. These anatomical differences may predispose these subjects to the development of cervical myelopathy compared to those with normal spinal canal diameters. Increased knowledge base of the epidemiology of this condition may lead to personalized clinical management and possibly early intervention to prevent spinal cord injuries in these patients.

Does Spinal Cord-Canal Mismatch Adversely Affect the Clinical Outcomes of Anterior Cervical Discectomy and Fusion for the Treatment of Cervical Myelopathy?

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

To clarify whether clinical outcomes of anterior cervical discectomy and fusion (ACDF), is affected by presence of spinal canal-cord mismatch (SCCM).

SUMMARY OF BACKGROUND DATA

SCCM is considered a factor that would moderately influence surgeons to perform posterior surgery since it could widen the spinal canal, while an anterior approach could only remove degenerative pathologies grown into the spinal canal.

MATERIALS AND METHODS

We retrospectively reviewed 186 patients who underwent ACDF and had been followed-up for more than two years. Patients with spinal cord occupation ratio (SCOR) of ≥0.7 were classified into the SCCM group, while those with a SCOR of <0.7 were included in the no-SCCM group. Patient demographics, cervical sagittal parameters, neck pain visual analog scale (VAS), arm pain VAS, and Japanese Orthopedic Association (JOA) score were assessed. JOA score was the primary outcome of the study.

RESULTS

One hundred and forty-seven patients (79.0%) were included into the no-SCCM group, while 39 patients (21.0%) were classified into the SCCM group. Postoperative radiographic parameters including C2-C7 lordosis, C2-C7 sagittal vertical axis, and range of motion did not significantly differ between the two groups. Neck pain VAS, arm pain VAS, and JOA score (no-SCCM group, from 13.7±2.5 to 14.6±2.3, P <0.001; SCCM group, from 13.8±1.6 to 15.0±2.0, P <0.001) significantly improved after the operation in both groups, and results were not significantly different between the two groups. Furthermore, SCOR was not significantly associated with JOA recovery rate at two years postoperatively in linear regression analysis.

CONCLUSION

Clinical and radiographic outcomes of ACDF were not affected by the presence of SCCM. Furthermore, SCOR was not significantly associated with neurological recovery at two years of follow-up. Therefore, ACDF can be safely and effectively applied for treating cervical myelopathy, regardless of the presence of SCCM, when other factors favor the anterior approach.

LEVEL OF EVIDENCE

Level III.

Reliability and validity of the pediatric adaptation of the mJOA scale for evaluating cervical spine disorders

PURPOSE

The study aimed to evaluate the validity and reliability of the pediatric adaptation of the Japanese Orthopedic Association (mJOA) scale in pediatric patients with various cervical spine pathologies.

METHODS

Initial assessments were performed by a neurosurgeon, followed by an independent evaluation by a neurologist within 1-2 days to test inter-rater reliability. The same clinician assessed the same group of children using the adapted mJOA scale at different point in time (between 1 month and 1 year after the initial assessment) to test intra-rater reliability. For known-groups validity, the pediatric mJOA scale assessments were compared between two groups of pathologies with different prognosis. Concurrent validity was assessed against the McCormick scale, and convergent validity was tested by reassessing patients using the adult mJOA scale two or more years after the initial assessment by pediatric one.

RESULTS

A cohort of 169 pediatric patients aged 6 months to 18 years (mean age: 10 ± 4.6 years) with various cervical spine pathologies was recruited. Pathologies included atlanto-axial rotatory fixation (AARF), Chiari type I anomaly, congenital cervical spine scoliosis, atlanto-axial dislocation (AAD) and instability (AAI), cervical spine stenosis and trauma, and congenital cervicothoracic dislocations. The majority of patients underwent cervical spine surgery and were followed up for an average of 6.9 ± 2.97 years. The pediatric mJOA scale demonstrated high inter-rater reliability (r = 0.99, p < 0.0001) and strong intra-rater reliability (r = 0.82, p < 0.0001). Significant differences in pediatric mJOA scores were observed between patients with expected-intact neurological status and those with expected-pathological neurological status (p < 0.0001). The pediatric mJOA scale showed a strong correlation with the McCormick grading system (r = 0.97, p < 0.001) and good correlation with the adult mJOA scale during long-term follow-up (r = 0.82, p < 0.0001).

CONCLUSIONS

The pediatric version of the mJOA scale is a reliable and valid tool for assessing pediatric patients with cervical spine disorders. Its high reliability and validity support its use in both clinical practice and research.

Impact of congenital spinal stenosis on the outcome of three-level anterior cervical discectomy and fusion in patients with cervical spondylotic myelopathy: a retrospective study

PURPOSE

To investigate whether congenital cervical spinal stenosis (CCSS) affects the outcome of three-level anterior cervical discectomy and fusion (ACDF) in patients with cervical spondylotic myelopathy (CSM).

METHODS

One hundred seventeen patients with CSM who underwent three-level ACDF between January 2019 and January 2023 were retrospectively examined. Patients were grouped according to presence of CCSS, which was defined as Pavlov ratio ≤ 0.75. The CCSS and no CCSS groups comprised 68 (58.1%) and 49 (41.9%) patients, respectively.

RESULTS

The Japanese Orthopaedic Association (JOA) score did not significantly differ between the two groups at any postoperative time point (p > 0.05). The JOA improvement rate was lower in the CCSS group 1 month after surgery (41.7% vs. 45.5%, p < 0.05), but showed no difference at any follow-up time point after one month. Multivariate logistic regression identified preoperative age (OR = 10.639), JOA score (OR = 0.370), increased signal intensity (ISI) in the spinal cord on T2-weighted MRI (T2-WI) (Grade 1: OR = 6.135; Grade 2: OR = 29.892), and degree of spinal cord compression (30-60%: OR = 17.919; ≥60%: OR = 46.624) as independent predictors of a poor one year outcome (JOA recovery rate < 50%).

CONCLUSION

Although early JOA improvement is slower in the CCSS group, it does not affect the final neurological improvement at 1 year. Therefore, CCSS should not be considered a contraindication for three-level ACDF in patients with CSM. The main factors influencing one year outcome were preoperative age, JOA score, ISI grade, and degree of spinal cord compression.

Defining multilevel developmental cervical spinal stenosis using MRI

Aims

Developmental cervical spinal stenosis (DcSS) is a well-known predisposing factor for degenerative cervical myelopathy (DCM) but there is a lack of consensus on its definition. This study aims to define DcSS based on MRI, and its multilevel characteristics, to assess the prevalence of DcSS in the general population, and to evaluate the presence of DcSS in the prediction of developing DCM.

Methods

This cross-sectional study analyzed MRI spine morphological parameters at C3 to C7 (including anteroposterior (AP) diameter of spinal canal, spinal cord, and vertebral body) from DCM patients (n = 95) and individuals recruited from the general population (n = 2,019). Level-specific median AP spinal canal diameter from DCM patients was used to screen for stenotic levels in the population-based cohort. An individual with multilevel (≥ 3 vertebral levels) AP canal diameter smaller than the DCM median values was considered as having DcSS. The most optimal cut-off canal diameter per level for DcSS was determined by receiver operating characteristic analyses, and multivariable logistic regression was performed for the prediction of developing DCM that required surgery.

Results

A total of 2,114 individuals aged 64.6 years (SD 11.9) who underwent surgery from March 2009 to December 2016 were studied. The most optimal cut-off canal diameters for DcSS are: C3 < 12.9 mm, C4 < 11.8 mm, C5 < 11.9 mm, C6 < 12.3 mm, and C7 < 13.3 mm. Overall, 13.0% (262 of 2,019) of the population-based cohort had multilevel DcSS. Multilevel DcSS (odds ratio (OR) 6.12 (95% CI 3.97 to 9.42); p < 0.001) and male sex (OR 4.06 (95% CI 2.55 to 6.45); p < 0.001) were predictors of developing DCM.

Conclusion

This is the first MRI-based study for defining DcSS with multilevel canal narrowing. Level-specific cut-off canal diameters for DcSS can be used for early identification of individuals at risk of developing DCM. Individuals with DcSS at ≥ three levels and male sex are recommended for close monitoring or early intervention to avoid traumatic spinal cord injuries from stenosis.

Three-dimensional Spinal Canal Morphometric Analysis and Relevant Spinal Cord Occupational Ratios in Congenital Cervical Spinal Stenosis: A Classification Algorithm of the Stenosis Phenotypes and Data-driven Decompression Approach

OBJECTIVES

No standardized magnetic resonance imaging (MRI) parameters have defined the 3-dimensional morphoanatomy and relevant spinal cord occupation ratios (occupation of spinal cord dimensions/similar dimensions within the spinal canal) in congenital cervical stenosis (CCS).

METHODS

A retrospective, comparative analysis was conducted on 200 patients >18 years of age with myelopathy and CCS (mean age, 52.4 years) and 200 age-matched controls with no myelopathy or radiculopathy. The variables assessed from high resolution MRI included sagittal and axial spinal canal dimensions (MRI Torg-Pavlov ratios) from C3 to C7. Morphometric dimensions from the sagittal retrodiscal and retrovertebral regions as well as axial MRI dimensions were compared. Sagittal and axial spinal cord occupation ratios were defined and correlated with spinal canal dimensions.

RESULTS

Multivariate analyses indicated reduced sagittal and axial anteroposterior (AP) spinal canal dimensions and a large reduction in transverse spinal canal dimensions at all spinal levels. There was a small significant correlation between AP sagittal spinal canal dimensions and axial transverse spinal canal dimensions at C3-C5, but not at C5-C6. Small correlations were noted between AP sagittal spinal canal dimensions and AP axial spinal cord and axial cross-sectional area occupation ratios at C3-C6, but there was no correlation with axial mediolateral spinal cord occupation ratios.

CONCLUSIONS

The stenosis effect can involve any dimension, including the transverse spinal canal dimension, independent of other dimensions. Owing to the varied observed morphoanatomies, a classification algorithm that defines CCS specific phenotypes was formulated. Objectivizing the stenosis morphoanatomy may allow for data-driven patient-focused decompression approaches in the future.

Evidence-based commentary on the diagnosis, management, and further research of degenerative cervical spinal cord compression in the absence of clinical symptoms of myelopathy

Degenerative cervical myelopathy (DCM) represents the final consequence of a series of degenerative changes in the cervical spine, resulting in cervical spinal canal stenosis and mechanical stress on the cervical spinal cord. This process leads to subsequent pathophysiological processes in the spinal cord tissues. The primary mechanism of injury is degenerative compression of the cervical spinal cord, detectable by magnetic resonance imaging (MRI), serving as a hallmark for diagnosing DCM. However, the relative resilience of the cervical spinal cord to mechanical compression leads to clinical-radiological discordance, i.e., some individuals may exhibit MRI findings of DCC without the clinical signs and symptoms of myelopathy. This degenerative compression of the cervical spinal cord without clinical signs of myelopathy, potentially serving as a precursor to the development of DCM, remains a somewhat controversial topic. In this review article, we elaborate on and provide commentary on the terminology, epidemiology, natural course, diagnosis, predictive value, risks, and practical management of this condition-all of which are subjects of ongoing debate.

Tetraparesis following thoracic spine surgery in a patient with Klippel-Feil syndrome and ABCB4 mutation: a case report

BACKGROUND

Klippel-Feil syndrome is a rare condition described in 1912 by Maurice Klippel and André Feil. It is defined as a congenital cervical fusion of at least two vertebrae, associated with a classical triad of clinical signs: short neck, low posterior hairline, and limited range of movement. However, Klippel-Feil syndrome manifests with a vast spectrum of phenotypes, ranging from no symptoms to complete triad, with or without other associated malformations. Most commonly, CCF results from sporadic mutations, even though autosomal recessive, autosomal dominant, or even X-linked inheritance can be detected. The ATP-binding cassette subfamily B member 4 is only expressed in the liver and is involved in biliary phospholipid secretion. The clinical spectrum includes various hepatobiliary pathologies, including low phospholipid-associated cholelithiasis, and has never been associated with musculoskeletal anomalies.

CASE PRESENTATION

A 55-year-old male Caucasian patient presenting with low phospholipid-associated cholelithiasis syndrome with ATP-binding cassette subfamily B member 4 mutation and liver cirrhosis was referred to our clinic for a liver transplant. A period of 6 months before, the patient underwent a T7-T9 posterior fixation for a T8 osteoporotic fracture. Postoperatively, he was tetraparetic, whereas he was neurologically intact before the operation. At admission to our hospital, he was still tetraparetic and presented with clinical signs of cervical myelopathy. Moreover, he suffered a limitation of cervical range of motion in all directions, short neck, and low posterior hairline. Imaging showed multiple cervical and thoracic vertebral bodies fusion, as well as cervical spine stenosis. Based on the available data, we diagnosed a type 3 Klippel-Feil syndrome according to Samartzis' classification.

CONCLUSIONS

The heterogeneity of KFS and the various potential hereditary links that are known indicate that it is important to highlight all potential cases related to known genetic defects. At present, no association between ATP-binding cassette subfamily B member 4 mutation and congenital cervical fusions has been reported. The other important clinical focus of this case is the appearance of spontaneous tetraparesis after thoracic spine surgery. This mechanism remains unclear, but considering different spinal anatomy it might have been due to difficult intubation and patient's positioning during his previous operation.

The imaging of cervical spondylotic myeloradiculopathy

This review provides a detailed description of the imaging features of cervical spondylotic myelopathy and radiculopathy, with a focus on MRI. Where relevant, we will outline grading systems of vertebral central canal and foraminal stenosis. Whilst post-operative appearances of the cervical spine are outside the scope of this paper, we will touch on imaging features recognised as predictors of clinical outcome and neurological recovery. This paper will serve as a reference for both radiologists and clinicians involved in the care of patients with cervical spondylotic myeloradiculopathy.

Is the type and/or co-existence of degenerative spinal pathology associated with the occurrence of degenerative cervical myelopathy? A single centre retrospective analysis of individuals with MRI defined cervical cord compression

BACKGROUND

Degenerative cervical myelopathy (DCM) arises from spinal degenerative changes injuring the cervical spinal cord. Most cord compression is incidental, referred to as asymptomatic spinal cord compression (ASCC). How and why ASCC differs from DCM is poorly understood. In this paper, we study a local cohort to identify specific types and groups of degenerative pathology more likely associated with DCM than ASCC.

METHODS

This study was a retrospective cohort analysis (IRB Approval ID: PRN10455). The frequency of degenerative findings between those with ASCC and DCM patients were compared using network analysis, hierarchical clustering, and comparison to existing literature to identify potential subgroups in a local cohort (N = 155) with MRI-defined cervical spinal cord compression. Quantitative measures of spinal cord compression (MSCC and MCC) were used to confirm their relevance.

RESULTS

ELF (8.7 %, 95 % CI 3.8-13.6 % vs 35.7 %, 95 % CI 27.4-44.0 %) Congenital Stenosis (3.9 %, 95 % CI 0.6-7.3 % vs 25.0 %, 95 % CI 17.5-32.5 %), and OPLL (0.0 %, 95 % CI 0.0-0.0 % vs 3.6 %, 95 % CI 0.3-6.8 %) were more likely in patients with DCM. Comparative network analysis indicated loss of lordosis was associated with ASCC, whilst ELF with DCM. Hierarchical Cluster Analysis indicated four sub-groups: multi-level disc disease with ELF, single-level disc disease without loss of lordosis and OPLL with DCM, and single-level disc disease with loss of lordosis with ASCC. Quantitative measures of cord compression were higher in groups associated with DCM, but similar in patients with single-level disc disease and loss of lordosis.

CONCLUSIONS

This study identified four subgroups based on degenerative pathology requiring further investigation.

Management of Cervical Spinal Cord Injury without Major Bone Injury in Adults

The incidence of cervical spinal cord injury (CSCI) without major bone injury is increasing, possibly because older people typically have pre-existing cervical spinal canal stenosis. The demographics, neurological injury, treatment, and prognosis of this type of CSCI differ from those of CSCI with bone or central cord injury. Spine surgeons worldwide are debating on the optimal management of CSCI without major bone injury. Therefore, this narrative review aimed to address unresolved clinical questions related to CSCI without major bone injury and discuss treatment strategies based on current findings. The greatest divide among spine surgeons worldwide hinges on whether surgery is necessary for patients with CSCI without major bone injury. Certain studies have recommended early surgery within 24 h after injury; however, evidence regarding its superiority over conservative treatment remains limited. Delayed MRI may be beneficial; nevertheless, reliable factors and imaging findings that predict functional prognosis during the acute phase and ascertain the necessity of surgery should be identified to determine whether surgery/early surgery is better than conservative therapy/delayed surgery. Quality-of-life assessments, including neuropathic pain, spasticity, manual dexterity, and motor function, should be performed to examine the superiority of surgery/early surgery to conservative therapy/delayed surgery.

Congenital Cervical Stenosis: a Review of the Current Literature

PURPOSE OF REVIEW

Congenital cervical stenosis (CCS) is a phenomenon in which an individual has a narrow canal due to abnormal anatomy which can present with earlier degenerative symptoms due to a reduced sagittal diameter. The diagnosis of CCS is important to individual treatment and preventative measures. Often, athletes are warned against sport participation that may cause damage to the cervical spine. There may be a predisposition in certain populations, but lack of data limits conclusions. The current review investigates recent literature on the definition, pathoanatomy, clinical presentation, and management of CCS. It specifically interrogates potential populations predisposed to this condition.

RECENT FINDINGS

The current literature reveals a potential predisposition for CCS in the black population when compared to the white population; however, many studies do not report race when discussing CCS patients. The lack of data limits a consensus on specific populations with a congenitally narrow canal. CCS may be more prevalent in specific populations. With knowledge of populations more at risk for this condition, physicians and teams can be alert when evaluating players and young adults. Furthermore, this may provide insight into risk for symptoms with degenerative disease. These findings introduce an avenue for further research into CCS.

Degenerative Cervical Myelopathy: Development and Natural History [AO Spine RECODE-DCM Research Priority Number 2]

STUDY DESIGN

Narrative review.

OBJECTIVES

To discuss the current understanding of the natural history of degenerative cervical myelopathy (DCM).

METHODS

Literature review summarizing current evidence pertaining to the natural history and risk factors of DCM.

RESULTS

DCM is a common condition in which progressive arthritic disease of the cervical spine leads to spinal cord compression resulting in a constellation of neurological symptoms, in particular upper extremity dysfunction and gait impairment. Anatomical factors including cord-canal mismatch, congenitally fused vertebrae and genetic factors may increase individuals' risk for DCM development. Non-myelopathic spinal cord compression (NMSCC) is a common phenomenon with a prevalence of 24.2% in the healthy population, and 35.3% among individuals >60 years of age. Clinical radiculopathy and/or electrophysiological signs of cervical cord dysfunction appear to be risk factors for myelopathy development. Radiological progression of incidental Ossification of the Posterior Longitudinal Ligament (OPLL) is estimated at 18.3% over 81-months and development of myelopathy ranges between 0-61.5% (follow-up ranging from 40 to 124 months between studies) among studies. In patients with symptomatic DCM undergoing non-operative treatment, 20-62% will experience neurological deterioration within 3-6 years.

CONCLUSION

Current estimates surrounding the natural history of DCM, particularly those individuals with mild or minimal impairment, lack precision. Clear predictors of clinical deterioration for those treated with non-operative care are yet to be identified. Future studies are needed on this topic to help improve treatment counseling and clinical prognostication.

A New Framework for Investigating the Biological Basis of Degenerative Cervical Myelopathy [AO Spine RECODE-DCM Research Priority Number 5]: Mechanical Stress, Vulnerability and Time

STUDY DESIGN

Literature Review (Narrative).

OBJECTIVE

To propose a new framework, to support the investigation and understanding of the pathobiology of DCM, AO Spine RECODE-DCM research priority number 5.

METHODS

Degenerative cervical myelopathy is a common and disabling spinal cord disorder. In this perspective, we review key knowledge gaps between the clinical phenotype and our biological models. We then propose a reappraisal of the key driving forces behind DCM and an individual's susceptibility, including the proposal of a new framework.

RESULTS

Present pathobiological and mechanistic knowledge does not adequately explain the disease phenotype; why only a subset of patients with visualized cord compression show clinical myelopathy, and the amount of cord compression only weakly correlates with disability. We propose that DCM is better represented as a function of several interacting mechanical forces, such as shear, tension and compression, alongside an individual's vulnerability to spinal cord injury, influenced by factors such as age, genetics, their cardiovascular, gastrointestinal and nervous system status, and time.

CONCLUSION

Understanding the disease pathobiology is a fundamental research priority. We believe a framework of mechanical stress, vulnerability, and time may better represent the disease as a whole. Whilst this remains theoretical, we hope that at the very least it will inspire new avenues of research that better encapsulate the full spectrum of disease.

Risk factors for the development of degenerative cervical myelopathy: a review of the literature

Degenerative cervical myelopathy (DCM) encompasses various pathological conditions causing spinal cord (SC) impairment, including spondylosis (multiple level degeneration), degenerative disc disease (DDD), ossification of the posterior longitudinal ligament (OPLL), and ossification of the ligamentum flavum (OLF). It is considered the most common cause of SC dysfunction among the adult population. The degenerative phenomena of DDD, spondylosis, OPLL and OLF, is likely due to both inter-related and distinct factors. Age, cervical alignment, and range of motion, as well as congenital factors such as cervical cord-canal mismatch due to congenital stenosis, Klippel-Feil, Ehler-Danlos, and Down syndromes have been previously reported as potential factors of risk for DCM. The correlation between some comorbidities, such as rheumatoid arthritis and movement disorders (Parkinson disease and cervical dystonia) and DCM, has also been reported; however, the literature remains scare. Other patient-specific factors including smoking, participation in contact sports, regular heavy load carrying on the head, and occupation (e.g. astronauts) have also been suggested as potential risk of myelopathy development. Most of the identified DCM risk factors remain poorly studied however. Further researches will be necessary to strengthen the current knowledge on the subject, especially concerning physical labors in order to identify patients at risk and to develop an effective treatment strategy for preventing this increasing prevalent disorder.

Acute on chronic cervical myelopathy causing cervical segmental myoclonus in a high-level wheelchair athlete: a case report

INTRODUCTION

This is a 20-year-old wheelchair athlete with history of caudal regression syndrome and cervical canal stenosis who developed spinal segmental myoclonus following routine intubation for an elective procedure.

CASE PRESENTATION

This patient is a 20-year-old man with history of caudal regression syndrome and chronic cervical stenosis. He is a high-level wheelchair racer and paralympic hopeful. This patient initially presented 18 months prior with shoulder abduction weakness. He was found to have cervical stenosis at C4, C5 on MRI. Neurosurgical treatment was not needed at that time as symptoms resolved. On this encounter, he presented for an elective urologic surgical procedure. Glidescope intubation was performed with notable cervical extension. In the Post Anesthesia Care Unit, the patient began experiencing twitching movements in his pectoral muscles bilaterally as well as left deltoid and biceps. His findings were consistent with myoclonus due to his cervical myelopathy. He was initially started on levetiracetam, but experienced dizziness. His symptoms were finally controlled with clonazepam. Neurosurgery performed cord decompression and fusion with resolution of his symptoms.

DISCUSSION

There are few cases of myoclonus secondary to myelopathy documented in literature. The current recommended treatments, levetiracetam and/or benzodiazepines, were successful in managing the myoclonus in this patient. However, cord decompression is necessary to avoid progression of myelopathic symptoms. In conclusion, myoclonus can be a presenting symptom of myelopathy and warrants further investigation, especially in patients with known spinal cord or vertebral pathology.

Extent and characteristic of relationships in canal dimension and canal body ratio between cervical and lumbar spine

A known prevalence of concurrent cervical and lumbar spinal stenosis was shown to be 5–25%, but there is a lack of evidence regarding direct relationships in canal dimension and canal-body ratio between cervical and lumbar spine. Total 247 patients (mean age: 61 years, male: 135) with cervical and lumbar computed tomography scans were retrospectively reviewed. Midsagittal vertebral body and canal diameters in reconstructed images were measured at all cervical and lumbar vertebrae, and canal-body ratios were calculated. The canal diameter and ratio were also compared according to the gender and age, and correlation analysis was performed for each value. There were significant correlations between cervical (C3–C7) and lumbar (L1–L5) canal dimension (p < 0.001). C5 canal diameter was most significantly correlated with L4 canal diameter (r = 0.435, p < 0.001). Cervical canal-body ratios (C3–C7) were also correlated with those of lumbar spine (L1–L5) (p < 0.001). The canal-body ratio of C3 was most highly correlated with L3 (r = 0.477, p < 0.001). Meanwhile, mean canal-body ratios of C3 and L3 were significantly smaller in male patients than female (p = 0.038 and p < 0.001) and patient’s age was inversely correlated with C5 canal diameter (r = − 0.223, p < 0.001) and C3 canal-body ratio (r = − 0.224, p < 0.001). Spinal canal dimension and canal-body ratio have moderate degrees of correlations between cervical and lumbar spine and the elderly male patients show the tendency of small canal diameter and canal-body ratio. This relationship of cervical and lumbar spine can be an important evidence to explain to the patients.

Spondylotic and Other Structural Myelopathies

PURPOSE OF REVIEW

This article highlights both common structural causes of myelopathy, such as spondylotic disease, and infrequent but treatable causes, such as syringomyelia, spinal cord herniation, arachnoid cyst, arachnoid band and web, epidural lipomatosis, Hirayama disease, and arachnoiditis.

RECENT FINDINGS

Neuroimaging improvements and availability have uncovered many structural abnormalities in the spines and spinal cords of patients who were asymptomatic or minimally symptomatic. Recent published clinical series have improved our knowledge of the natural history of structural abnormalities and the risks of intervention versus conservative management.

SUMMARY

Myelopathy from a suspected structural cause is a common reason for neurologic consultation. Correlation between the history, examination, and imaging are especially important to determine whether intervention is necessary or conservative management is the best option.

Advanced Quantitative Spine Imaging

Although advanced quantitative imaging may not be currently used to any degree in the routine reporting of spinal examinations, this situation will change in the not too distant future. Advanced quantitative imaging has already allowed us to understand a great deal more regarding spinal development, marrow physiology, and disease pathogenesis. Radiologists are ideally suited to drive this research forward. To speed up this process and optimize the impact of studies reporting spine quantitative data, we should work toward universal standards on the acquisition of spine data that will allow quantitative studies to be more easily compared, contrasted, and amalgamated.

Surgical Outcomes in Patients with Congenital Cervical Spinal Stenosis

OBJECTIVE

To evaluate the differences in surgical outcomes of patients with cervical spondylotic myelopathy with and without congenital cervical spinal stenosis (CCSS).

METHODS

Institutional review board approval was obtained to conduct a retrospective chart review of patients with cervical spondylotic myelopathy who underwent decompression and fusion surgeries from 2010-2016 at a single institution. CCSS was identified using the Torg-Pavlov ratio on lateral cervical radiographs. Pre- and postoperative outcome measures were assessed using the modified Japanese Orthopedic Association (mJOA) and the EuroQol 5-dimension questionnaire (EQ-5D).

RESULTS

Of 208 patients, Torg-Pavlov ratio identified 85 patients with CCSS. There were no significant differences between the CCSS patient and control patient groups in EuroQol 5-dimension questionnaire and mJOA scores at all 4 designated time points in the study (preoperative, earliest postoperative, 6 month postoperative, and 1 year postoperative). Although not statistically significantly, there was a notable trend for patients with CCSS to be less likely to have mJOA-defined severe myelopathy at the postoperative (odds ratio [OR], 0.75; P = 0.38), 6 month postoperative (OR, 0.66; P = 0.20), and 1 year postoperative (OR, 0.64; P = 0.14) time points.

CONCLUSIONS

Postoperatively, compared with non-CCSS patients, patients with congenital cervical stenosis reported equal quality of life for all markers. Our findings suggest that in patients with CCSS and relatively mild symptoms of myelopathy, equal consideration should be given for surgical intervention. The findings of this study warrant further large-scale, multi-institutional investigation to further understand the generalizability of these surgical outcome results.

Degenerative Cervical Myelopathy: A Brief Review of Past Perspectives, Present Developments, and Future Directions

Degenerative cervical myelopathy (DCM) is the most common cause of spinal cord injury in developed countries; its prevalence is increasing due to the ageing of the population. DCM causes neurological dysfunction and is a significant cause of disability in the elderly. It has important negative impacts on the quality of life of those affected, as well as on their caregivers. DCM is triggered by a variety of degenerative changes in the neck, which affect one or more anatomical structures, including intervertebral discs, vertebrae, and spinal canal ligaments. These changes can also lead to structural abnormalities, leading to alterations in alignment, mobility, and stability. The principle unifying problem in this disease, regardless of the types of changes present, is injury to the spinal cord due to compression by static and/or dynamic forces. This review is partitioned into three segments that focus on key elements of the past, the present, and the future in the field, which serve to introduce the focus issue on "Degenerative Cervical Myelopathy and the Aging Spine". Emerging from this review is that tremendous progress has been made in the field, particularly in recent years, and that there are exciting possibilities for further advancements of patient care.

Cervical Cord Injury Following Posterior Spinal Fusion in a Patient With Adolescent Idiopathic Scoliosis: A Case Report

CASE

We present an 11-year-old girl with adolescent idiopathic scoliosis who underwent uncomplicated posterior spinal fusion and developed transient upper extremity weakness secondary to a cervical cord injury several hours after the conclusion of the case.

CONCLUSIONS

Perioperative hypotension, positioning, and mild cervical canal stenosis contributed to cervical cord injury following posterior thoracic instrumentation. Optimal perioperative resuscitation and awareness of cervical spine anatomy along with proper positioning may prevent this rare but potentially serious complication.