Introduction: Many researchers have reported the outcome after surgical treatment in cervical myelopathy, however, regarding to severe gait disturbance, what extent of improvement could be obtainable has not been clarified yet. We investigated the postoperative improvement of the ambulatory level and prognostic factors in non‐ambulatory patients with cervical myelopathy.
Materials and Methods: A total of 131 non‐ambulatory patients surgically treated due to cervical myelopathy (78 males, 53 females; mean age 71.5 years) were followed for an average of 3.0 years (range 1.0 ‐ 8.6 years). Their walking ability at the follow‐up period was compared to the preoperative condition by Japanese Orthopaedic Association (JOA) scores and lower‐extremity function subscores (L/E subscores); graded “excellent” (2 points or more), “good” (1.5 points), “fair” (one point), and “poor” (0.5 or 0 points). Disease durations (from the onset of myelopathy symptoms or gait disturbance to the time of surgery) were also investigated. The data were analyzed by the Wilcoxon signed‐rank test and the chi‐squared analysis (p < 0.05).
Results: Preoperative L / E subscore was one point in 71 patients, 0.5 in 30 patients, and 0 in 30 patients. The mean L/E subscore improved significantly from 0.7 to 1.6 points (p < 0.01). Fifty patients were graded as “excellent” (38%) and 21 patients as “good” (16%), indicating 54% of the improvement of non‐ambulatory condition as to walk without support at the follow‐up period. Seventy one patients whose preoperative L/E subscores presented one point improved significantly better than the other 60 patients (preoperative L/E subscores were less than one point), where the mean L/E subscore was 1.7 and 1.4 points respectively (p < 0.05). On the assessment of the 60 non‐ambulatory patients even with any support (preoperative L/E subscore; 0.5 or 0 points), 26 patients (43%) recovered enough to walk without support and 17 patients (28%) were graded as “excellent”. Of those 60 patients, 17 patients graded as “excellent” had shorter durations of myelopathy symptoms and / or gait disturbance (7.9 and 3.8 months respectively) than the others (29.5 and 8.9 months respectively) (p < 0.05). In these 60 patients, ROC curve showed the cut‐off values of the duration of myelopathy symptoms and gait disturbance provided the improvement to “excellent” were three and two months. Twelve of 22 patients operated within three months from the onset of myelopathy were evaluated as “excellent”, which was significantly high compared to five of 38 patients operated after three months (p < 0.01). Likewise, the onset of gait disturbance influenced their recoveries significantly in the patients operated within two months (12 of 27 patients) compared to after two months (5 of 33 patients) (p < 0.01).
Conclusion: We demonstrated that 54% of non‐ambulatory patients due to cervical myelopathy recovered up to the level without need for a support after surgery. To expect better walking ability, surgery should be performed while walking ability is reserved. Also, we concluded surgical treatment should be performed within three months after the onset of myelopathy or two months after the onset of gait disturbance for obtaining improvement from non‐ambulatory condition with imperative support to stable gait (L/E subscore; 2 points or more).