General Session: MIS - Hall F
Presented by: K. Cardinal
B. Basques(1), B. Haws(1), B. Khechen(1), P. Louie(1), K. Movassaghi(1), K. Cardinal(1), J. Guntin(1), K. Singh(1)
(1) Rush University Medical Center, Orthopaedic Surgery, Chicago, IL, United States
Introduction: There is considerable debate regarding the appropriate duration of nonoperative treatment before surgery is considered for a lumbar disk herniation. Moreover, it is unknown if extended nonoperative treatment has implications for long term clinical outcomes even after surgery is performed.
Aims: To characterize the effect of preoperative symptom duration on postoperative outcomes following minimally invasive lumbar microdiscectomy (MIS LD).
Methods: A prospectively-maintained surgical registry of patients undergoing MIS LD by a single surgeon between 2013-2016 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 was 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< 0.05.
Results: After exclusion of those with incomplete data, a total of 87 patients were identified, 34 with symptom duration ≤6 months and 43 with symptom duration >6 months. No differences in baseline or perioperative characteristics were found (p>0.05). When comparing patient reported outcomes, patients with shorter symptom duration had significantly lower ODI scores preoperatively (p=0.044). Additionally, a significantly greater improvement in ODI scores at 6 weeks (p = 0.011), 12 weeks (p = 0.024), and 6 months (p = 0.003) was found for patients with shorter preoperative symptom duration. Patients with shorter symptom duration also obtained MCID for ODI at a significantly greater rate than those with longer duration of symptoms (p=0.003). Additionally, patients with a shorter duration of symptoms had significantly greater improvement in VAS leg pain at 6-months (p=0.037), though this was not statistically significant at earlier time points. For VAS back pain, no differences were found between groups.
Conclusion: Patients that underwent MIS LD within 6 months of symptom onset had similar baseline characteristics but increased preoperative disability 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 non-operative treatment in the setting of lumbar disk herniations particularly as it may potentially impair functional recovering following delayed surgical intervention.