Biceps involvement and degree of motor deficit at diagnosis are independently predictive of timing of postoperative C5 palsy recovery.

Background Context: C5 palsy is a debilitating complication following cervical spine surgery. This is the largest single-institution study evaluating C5 palsy and is specifically aimed at risk factors predictive of recovery timing.

Purpose: To assess the impact of demographic, radiographic, and surgical factors on C5 palsy recovery timing.

Study Design: Retrospective cohort study.

Patient Sample: Adult patients with postoperative C5 palsy following anterior cervical discectomy and fusion (ACDF), posterior cervical decompression and fusion (PCDF), combined ACDF/PCDF, or laminoplasty between 2010 and 2023.

Outcome Measures: C5 palsy recovery at 6 months and 1 year after surgery, postoperative opioid consumption, cervical alignment measurements including (1) C2-C7 cobb angle, (2) C2-C7 sagittal vertical axis, (3) C2 slope, (4) C2 tilt, and (5) T1slope.

Methods: Demographics, surgical and radiographic variables were recorded. Patients were divided based on resolution of symptoms to the level of their preoperative strength versus persistence of symptoms at 6 months and 1 year after surgery. Appropriate statistical analysis was performed with alpha <0.05.

Results: 93 patients had postoperative C5 palsy (63-PCDF, 21-ACDF, 6-ACDF/PCDF, 3-laminoplasty). Patients whose C5 palsy persisted at 6 months were more likely to be male, older, and have higher Charlson Comorbidity Index. At 1 year, those with persistent symptoms were demographically similar to those with resolution. Preoperative radiographic variables (C2-C7 Cobb angle and SVA, C2 tilt and slope, and T1 slope) were not associated with recovery timing at either timepoint. Multivariable logistic regression identified biceps involvement at C5 palsy diagnosis as independently predictive of persistence of symptoms at 6 months, and degree of both biceps and deltoid weakness as predictive at both timepoints (6 months: odd ratio=1.92; p=0.005; 1 year: estimate-1.90; p=0.011). 71% of all patients recovered within 1 year.

Conclusions: The presence of biceps involvement independently predicted persistence of C5 palsy at 6 months. The severity of biceps and deltoid motor deficit independently predicted persistence of C5 palsy both timepoints. Identifying these risk factors can help to inform patient counseling regarding the recovery dynamics of C5 palsy.