Wednesday, September 26, 2018 7:35 AM–9:00 AM ePosters: P101. Favorable prognosis for significant preoperative upper extremity weakness following elective anterior cervical discectomy and fusion

BACKGROUND CONTEXT Cervical radiculopathy secondary to cervical spondylosis can manifest as pain, sensory disturbance, and/or motor deficit. While preoperative weakness is often used as an indication for early surgical intervention, few studies have examined the prognosis for upper extremity motor deficit following anterior cervical discectomy and fusion (ACDF). PURPOSE To determine the prognosis for motor recovery after anterior cervical discectomy and fusion in patients with preoperative motor weakness. STUDY DESIGN/SETTING Retrospective cohort. PATIENT SAMPLE Consecutive patients undergoing elective ACDF from September 2015 until June 2016. OUTCOME MEASURES Postoperative motor strength in all affected myotomes. METHODS We retrospectively examined a cohort of 618 consecutive patients that underwent elective ACDF from September 2015 until June 2016. Cases were performed by ten fellowship trained spine surgeons at our tertiary academic center. Data was collected regarding patient demographics and comorbidities. Cervical magnetic resonance imaging imaging was reviewed for the presence of cord compression, myelomalacia, and foraminal stenosis. Patients were divided into a group exhibiting significant preoperative weakness (Medical Research Council motor grade less than 4) and a group without significant weakness. Data regarding affected muscle groups and significant improvement postoperatively (to a motor grade 4 or greater) was recorded. Univariate analysis was performed to determine risk factors for failure to improve. RESULTS Overall, out of the 618 patients, 47.5% were male with an average age of 56.3years. 43.0% of patients exhibited myeloradiculopathy with 57% having exclusively cervical radiculopathy. Of those patients with myelopathy and cord compression, 40.5% demonstrated myelomalacia on cervical MRI. Average follow up was 6.2 months. Two-level fusions were most commonly performed (44.6%) followed by one-level (29.3%), three-level (21.7%), and four-level (4.4%) fusions. A total of 4.3% of patients demonstrated significant preoperative weakness. Of these patients, 57.1% of them had more than one muscle group affected. Triceps were the most commonly affected muscle group (26.9%) followed by hand intrinsics (23.1%), finger flexors (20.5%), deltoids (15.4%), and biceps (14.1%). Postoperatively, 75.3% of patients experienced an improvement in muscle strength (≥4). Despite being the most commonly weak muscle preoperatively, triceps most frequently showed improvement (95.2%) followed by finger flexors (87.5%), hand intrinsics (83.3%), and biceps (63.6%). Deltoids were much less likely to show improvement following surgery (8.3%). In a univariate analysis, myelomalacia on imaging (OR 28.9, p CONCLUSIONS This cohort's outcomes would suggest with intermediate follow up one can expect the vast majority (over 70%) of patients to show marked strength improvement postoperatively after ACDF. These results are encouraging for patients undergoing ACDF with significant preoperative motor weakness. However, patients with myelomalacia seem to be at risk for not improving, and should be counseled that their prognosis for strength improvement is more guarded.