Analysis of C5 palsy in cervical myelopathy with massive anterior compression following laminoplasty.

Abstract

Little data is available about comparison of the incidence and clinical characteristics of the C5 palsy between patients of cervical myelopathy with occupying ratio greater than 50% and those with occupying ratio less than 50% following laminoplasty. One-hundred eighteen patients with cervical myelopathy who underwent open door laminoplasty were reviewed in this study. The patients were divided into two groups: group A comprising 55 patients with an anterior occupying ratio greater than 50% and group B comprising 63 patients with an anterior occupying less than 50%. Clinical and radiological outcomes were assessed between two groups. No statistically difference was found in preoperative Japanese Orthopedic Association (JOA) score of both groups (10.7 ± 1.7 in group A vs 10.9 ± 1.1 in group B, P > 0.05). Improvements in postoperative JOA score were achieved, and there was a statistical difference (14.0 ± 1.4 in group A vs 14.8 ± 0.9 in group B, P < 0.05). Group A had a lower rate of recovery than group B (P < 0.05). Totally, 12 of 118 (10.2%) patients developed the C5 palsy postoperatively. C5 palsy occurred in 3 of 63 patients in the group B compared with 9 of 55 in the group A. Statistically significant difference was found in the incidence of C5 palsy between the two groups (P < 0.05). Furthermore, patients in group A required significantly longer recovery periods than group B. Both preoperative and postoperative MRI presented more levels of T2 high-signal lesion in group A than group B. The degree of posterior shift of the cord after posterior decompression in group A was less than group B (P < 0.05). Patients with a high degree of anterior compression have higher risk of C5 palsy than those with a relative low degree of anterior compression.