Wednesday, September 26, 2018 7:35 AM–9:00 AM ePosters

Abstract

BACKGROUND CONTEXT There is considerable debate regarding the appropriate duration of nonoperative treatment before surgery is considered for a lumbar disc herniation. Moreover, it is unknown if extended nonoperative treatment has implications for long term clinical outcomes even after surgery is performed. PURPOSE To characterize the effect of preoperative symptom duration on postoperative outcomes following minimally invasive lumbar microdiscectomy (MIS LD). STUDY DESIGN/SETTING Retrospective cohort. PATIENT SAMPLE A total of 94 patients who underwent a MIS LD between 2013 and 2017. OUTCOME MEASURES Improvements in ODI, VAS back and VAS leg scores from preoperative to postoperative time points (6 week, 12 week and 6 month). METHODS A prospectively maintained surgical registry of patients undergoing MIS LD by a single surgeon between 2013 and 2017 was reviewed. Preoperative symptom duration was dichotomized into two groups (≤6 months, >6 months). Only patients with full clinical data at 6 months postoperative follow-up were included in the study. Clinical outcomes including Oswestry Disability Index (ODI), Visual Analog Scale (VAS) back, and VAS leg were assessed at 6 weeks, 12 weeks and 6 months postoperative. The amounts of patients obtaining a minimum clinically important difference (MCID) for each clinical outcome were also assessed. Groups were compared with chi-square analysis and student t-tests for categorical and continuous data, respectively. Statistical significance was set at p RESULTS After exclusion of those with incomplete data, a total of 94 patients were identified, 45 with symptom duration ≤6 months and 49 with symptom duration >6 months. No differences in baseline or perioperative characteristics were found (p>.05). When comparing patient reported outcomes, patients with shorter symptom duration had significantly greater improvement in ODI scores at 6 weeks (P=.004), 12 weeks (P=.022) and 6 months (P=.005) was found for patients with shorter preoperative symptom duration. Patients with shorter symptom duration also obtained MCID for ODI at a greater rate than those with longer duration of symptoms, (p=.015). Additionally, patients with a shorter duration of symptoms had greater postoperative improvements in VAS leg pain, though this was not statistically significant. For VAS back pain, no differences were found between groups. CONCLUSIONS Patients that underwent MIS LD within 6 months of symptom onset had similar baseline characteristics compared to patients who underwent surgery after 6 months. However, the patients with shorter preoperative symptom duration had greater clinical improvement postoperatively. Further studies should evaluate the efficacy of nonoperative treatment in the setting of lumbar disc herniations particularly as it may potentially impair functional recovering following delayed surgical intervention.