Risk Prediction for Development of Traumatic Cervical Spinal Cord Injury without Spinal Instability

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 and Prognosis for Acute Progression of Myelopathic Symptoms in Patients Ossification of the Posterior Longitudinal Ligament After Minor Trauma

STUDY DESIGN

A retrospective cohort study.

OBJECTIVE

The aim of this study was to identify the risk factors for acute progression of myelopathic symptoms (PMS) associated with ossification of the posterior longitudinal ligament (OPLL) after minor trauma and to compare the prognosis between an acute PMS group and a chronic PMS group.

SUMMARY OF BACKGROUND DATA

Although the prevalence of OPLL among patients with cervical myelopathy is high, few studies have been published regarding the risk factors for acute PMS associated with OPLL after minor trauma.

METHODS

Patients with OPLL who had histories of minor trauma and had undergone surgery were divided according to clinical course into an acute (within 48 hours, n = 38) and a chronic PMS group (n = 32). The type of trauma and the clinical and radiologic characteristics were compared. The clinical outcomes were also compared at admission and at 1 and 2 years postoperatively.

RESULTS

The types of trauma were significantly different between the two groups (P < 0.05). Univariate analysis revealed that older age, a narrower space available for the cord, and a higher rate of stenosis in the spinal canal were associated with acute PMS after minor trauma (P = 0.014, 0.020, and 0.006, respectively). However, the rate of stenosis in the spinal canal was the only risk factor that was identified in a multivariate analysis (P = 0.023; odds ratio, 0.872; 95% confidence interval, 0.774-0.982). The Japanese Orthopedic Association scores at the initial visit and at postoperative years 1 and 2 were significantly lower in the acute PMS group than in the chronic PMS group (P < 0.001, P < 0.001, and P < 0.001, respectively).

CONCLUSION

One risk factor for acute PMS in patients with OPLL after minor trauma is a higher rate of stenosis of the spinal canal. Patients with acute PMS exhibited unfavorable neurologic outcomes. Preventive surgical treatment may be recommended for patients with significant OPLL with mild cervical myelopathy.

LEVEL OF EVIDENCE

3.

Kinematic analysis of cervical spine canal diameter and its association with grade of degeneration

OBJECTIVES

To investigate the cervical spinal canal diameters variance under positional MRI, and also the relationship between cervical canal diameter variance rate and grade of degeneration.

METHODS

From January 2013 to January 2015, a consecutive of 273 symptomatic patients (166 males and 207 females) with an average age of 44.6 years (range 21-89 years) underwent positional cervical MRI. T2-weighted sagittal images of 1638 cervical intervertebral discs from 273 subjects were classified into five grades. The canal diameter and canal diameter variance rate at three positions and their comparison among five grade of degeneration were evaluated. The measurements were tabulated and analyzed using SPSS. 13.0. p values less than 0.05 were considered to indicate a statistically significant difference.

RESULTS

The sagittal cervical canal diameter at the C5/6 level were the smallest compared with the other levels regardless of neutral, flexion or extension positions, C5/6 level had the largest canal diameter variance rate in both flexion and extension (8.14 ∓ 0.38 and 7.81 ∓ 0.31 %, respectively), second was C4/5 level (7.65 ∓ 0.39 and 7.67 ∓ 0.32 %, respectively). A total of 1638 discs were classified into 5 groups, each level showed the similar tendency that no matter what position, with the increasing grade of degenerative disc degree, spine canal diameter decreased gradually. For C5/6 under extension and flexion position, significant difference was also noted between grade 2 and 3; For C4/5 under extension position, significant difference existed between grade 1 and 2, grade 1 and 3, while under flexion position, significant difference existed between grade 2 and 4, and the results also showed no significant difference at the same degree of degeneration on both levels between extension and flexion position.

CONCLUSIONS

C5/6 and C4/5 is of higher risk of suffering SCI than other levels, C4/5 level predispose SCI at earlier stage than C5/6, patients presenting with intermediate signal and slight decreased disc height on T2 weighted MRI at C4/5 level should be paid attention.