Outcome and Predictive Factors in Rapid Progressive Cervical Spondylotic Myelopathy: A Retrospective Case-Control Study

Abstract

Background: To evaluate epidemiological, clinical and radiographic features in the development and prognosis of rapid progressive cervical spondylotic myelopathy (rp-CSM).Methods: A retrospective study of 175 patient records was performed between March 2011 and January 2017. Patients were divided into rp-CSM group and chronic CSM (c-CSM) group according to the deterioration time and severity of preoperative neurological dysfunction. After selection, 25 rp-CSM patients were matched to a control group of 75 patients with c-CSM. The clinical outcomes were assessed by the Modified Japanese Orthopaedic Association (mJOA) score at six different follow-up time points. The imaging parameters including Torg-Pavlov Ratio (TPR) on conventional lateral x-ray and magnetic resonance images (MRI), intervertebral disc level compression ratio and increased signal intensity (ISI) on T2W1 were analyzed between the two groups, and predictors for rapid neurological dysfunction in CSM patients were evaluated using multivariate analysis.Results: Twenty-five patients experienced rp-CSM (18 males; median age 59.04 ± 12.81 years) and were matched with Seventy-five control subjects that with CSM without rapid progression (54 males; median age 56.88 ± 12.31 years). The average time to develop severe neurological deterioration was 0.8 month in rp-CSM group and 24 month in c-CSM group (p=0.001), preoperative mJOA were 6 in rp-CSM patients and 12 in c-CSM patients (p=0.014) and rp-CSM patients demonstrated worse outcomes than the controls in one year after surgery (mJOA improvement rate 54.5% and 80%, p=0.021). There were no differences between the two groups except the history of diabetes and the long-term smoking in basic condition, radiographic measurements signified that TPR MRI, intervertebral disc level compression ratio and increased signal intensity (ISI) on T2W1 were inferior in patients with rp-CSM than patients with c-CSM. Regression analysis verified that the history of diabetes, TPR MRI < 0.4, compression ratio ≥50%, the sagittal diameter of ISI ≥50% of spinal canal diameter on T2W1 have significant correlations with the rapid progressive neurological dysfunction in patients with CSM. Conclusion: The prognosis of rapid progressive CSM is worse than that of common chronic CSM. The rapid neurological deterioration can be identified by TPR MRI (< 0.4), compression ratio (≥50%), sagittal diameter of ISI (≥50% of spinal canal diameter). Besides, a history of diabetes was also a negative factor for these patients.