Radiculopathy of C-5 after anterior decompression for cervical myelopathy

Object. The authors conducted a study to examine the incidence and causes of postoperative C-5 radiculopathy, and they suggest preventive methods for C-5 palsy after anterior corpectomy and fusion. Methods. The authors included in the study 18 patients with postoperative C-5 radiculopathy from 563 patients who underwent anterior decompression and fusion for cervical myelopathy. There were 10 cases of ossification of the posterior longitudinal ligament (OPLL) and eight cases of cervical spondylotic myelopathy (CSM). All patients received conservative treatment. Posttreatment full recovery was present in eight patients, and Grade 3/5 strength was documented in six in whom some weakness remained. Radiographic evaluation revealed that the C3-4 and C4-5 cord compression was significantly more severe in patients with paralysis than in those without paralysis. The incidence of paralysis was higher in patients with OPLL than in those with CSM (chi-square test, p = 0.03). The incidence of paralysis increased in parallel with the number of fusion levels (correlation coefficient r = 0.94). Multivariate analysis revealed that the final manual muscle testing (MMT) value was closely related to the preoperative MMT value (computed t value 4.17; p < 0.01) and preoperative Japanese Orthopaedic Association (JOA) score for cervical myelopathty (computed t value, 2.75; p < 0.05). Conclusions. Preexisting severe stenosis at C3-4 or C4-5 in patients with OPLL is a risk factor for paralysis. Preoperative muscle weakness and a low JOA score are factors predictive of poor recovery.