171. Postoperative recovery of motor strength and patient-reported physical function following anterior cervical discectomy and fusion

Abstract

BACKGROUND CONTEXT While anterior cervical discectomy and fusion (ACDF) reportedly decreases neurological deficits, pain frequency and pain intensity, the functional outcomes are less clearly elucidated in the spine literature. Though consistent improvements from baseline in upper extremity strength have been noted following ACDF, the timeline of these improvements needs further evaluation. This study identifies the motor strength recovery timeline and further elaborates on the association between clinically-appreciable motor and patient-reported physical function recovery following ACDF. METHODS Patients undergoing elective, primary ACDF were identified from a single academic institution between 01/01/2013 – 09/01/2018. PROMIS computer adaptive test (CAT) data was prospectively obtained and retrospectively analyzed. Inclusion criteria included ages >18 years-old, clinical diagnosis of cervical radiculopathy and/or myelopathy confirmed on radiographic imaging, the ability to read/write English and provide informed consent. Exclusion criteria included revision surgery, combined anterior/posterior surgery, tumor, trauma, or infectious diagnoses. All surgeries were performed by one of three fellowship-trained spine surgeons. Demographic and surgical data, including the degree of motor weakness, were obtained from the hospital chart. In order to grade the degree of weakness, points were given for each strength deficit (eg, +1 points for each 4/5 muscle group). The minor preoperative weakness group was defined as total strength deficit RESULTS A total of 107 patients were identified. Baseline PROMIS physical function (PF) T-scores showed a statistically significant difference based on level of preoperative motor weakness (p=0.01). O patients with minor preoperative weakness, 62.5% achieved full strength recovery 1.5 months postoperatively compared to 38.5% of those with major preoperative weakness. PF T-scores increased throughout the postoperative period regardless of the level of preoperative weakness. However, the timeline of these gains in physical functioning differed. The majority of physical function recovery for minor weakness patients occurred in the first 1.5 months postoperatively while the physical function recovery for major weakness patients occurred over the course of 3 months postoperatively. CONCLUSIONS Our results indicate that the severity of the preoperative motor weakness influences the rate and degree of recovery. We highlight important features of both postoperative motor and patient-reported physical function recovery. While both weakness groups improved with treatment, patients with major preoperative motor weakness demonstrated longer time for recovery, poorer improvement to full strength, and worse functional results. Spine providers may use these results to better counsel ACDF patients on the general milestones of strength and functional recovery in the postoperative period. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.