20 - The Safety and Clinical Effectiveness of Biportal Endoscopic Lumbosacral Decompression in the Outpatient ASC vs. Inpatient Hospital Setting

Introduction
Endoscopic spine surgery has grown in popularity recently due to its potential benefits, including reduced pain and faster recovery. Endoscopic spine surgery is increasingly utilized to treat lumbar disc herniation and lumbar spinal stenosis. There is little evidence to demonstrate the safety and clinical effectiveness of employing the biportal spinal endoscopy for lumbosacral decompression in the outpatient ambulatory surgical center (ASC) setting.

Methods:
This is a retrospective review of prospectively collected data of patients undergoing biportal endoscopic discectomy for lumbar disc herniation and unilateral laminotomy, decompression for lumbar stenosis in the ASC setting as compared to the inpatient setting. Demographic data, surgical complications, and patient-reported outcomes were reviewed. Postoperative complications included reoperation, readmission, inflammatory radiculitis, postoperative weakness, symptom recurrence, wound infection or dehiscence, or recurrent disc herniation. Demographic data, Visual Analog Scale (VAS) back and leg pain scores, and Oswestry Disability Index (ODI) scores, postoperative complications (reoperation, readmission, inflammatory radiculitis, postoperative weakness, symptom recurrence, wound infection or dehiscence, or recurrent disc herniation) were collected and analyzed. Statistics were calculated amongst treatment groups using unpaired t test and chi square analysis where appropriate. Statistical significance was determined as p< 0.05.

Results: 62 patients were identified. 41 cases (66%) were performed an ASC, while 21 (34%) were performed in the inpatient setting. Statistically significant differences in age, ASA score, Charlson Comorbidity Index were seen between cohorts (Table 1). There were no significant differences in intraoperative blood loss but there were significantly lower drain duration and output in the outpatient ASC cohort (Table 2). No significant difference was found between postoperative complications of outpatient vs inpatient cohorts (Table 2). There were no reoperations or readmissions during the follow-up period. VAS Back scores significantly improved from 5.85 ± 2.20 and 5.57 ± 2.06 preoperatively in the outpatient and inpatient cohorts respectively to 0.67 ± 1.15 and 3 ± 2.94 in the outpatient and inpatient cohorts respectively at final follow up (p < 0.0001). VAS Leg scores significantly improved from 6.87 ± 1.54 and 6.95 ± 2.33 preoperatively in the outpatient and inpatient cohorts respectively to 1.67 ± 1.53 and 1.25 ± 2.5 in the outpatient and inpatient cohorts respectively at final follow up (p < 0.0001). ODI scores significantly improved from 38.6% ± 12.6% and 49.7% ± 16.3% preoperatively in the outpatient and inpatient cohorts respectively to 13% ± 1.41% and 33% ± 22.3% in the outpatient and inpatient cohorts respectively at final follow up (p < 0.0001). No significant differences amongst VAS or ODI scores were determined between the outpatient and inpatient cohorts.

Conclusions: While the safety and efficacy of biportal endoscopic spine surgery is increasingly documented in the literature, there is no evidence to date on the use of the technique in the outpatient ASC setting. This study demonstrates that biportal endoscopic lumbosacral decompression can be successfully performed in the outpatient and inpatient settings with similar clinical effectiveness and low rates of complications in the early follow-up period. Longer term follow-up is necessary.