Clinical Course and Prognostic Factors of C5 Palsy after Cervical Spine Surgery

This retrospective multicenter cohort study investigated recovery trajectories and prognostic factors after postoperative C5 palsy (C5P) following cervical spine surgery. Sixty-three patients from 11 institutions who developed new-onset or worsened deltoid and/or biceps weakness within two months postoperatively were analyzed. Full recovery, defined as return to or beyond the preoperative manual muscle testing (MMT) grade, was achieved in 50 patients (79.4%), whereas 13 patients (20.6%) showed incomplete recovery. Multivariate logistic regression demonstrated that higher preoperative MMT grade and higher MMT grade at the onset of C5P were independently associated with a lower risk of incomplete recovery. Kaplan-Meier analysis further showed that patients with higher preoperative or postoperative MMT grades experienced significantly faster motor recovery. Subgroup analysis stratified by preoperative motor status and postoperative palsy severity suggested that preoperative motor function may be associated with greater recovery potential after postoperative C5P. However, this interpretation should be made cautiously because some subgroups included only a small number of patients. These findings indicate that both preoperative motor function and motor severity at palsy onset are clinically relevant indicators of recovery. Careful preoperative neurological assessment and early postoperative evaluation may help guide prognostic counseling, rehabilitation planning, and postoperative management for patients who develop postoperative C5P.