Abstract
BACKGROUND: Previous lumbar spine surgery is a frequent exclusion criterion for studies evaluating lumbar surgery outcomes. In real-life clinical settings, this patient population is important, as a notable proportion of patients evaluated for lumbar spine surgery have undergone prior lumbar surgery already previously. Knowledge about the long-term outcomes after microdiscectomy on patients with previous lumbar surgery and how they compare to those of first-time surgery is lacking. METHODS: The original patient cohort for screening included 615 consecutive patients who underwent surgery for lumbar disc herniation, with a median follow-up time of 18.1 years. Of these patients, 89 (19%) had undergone lumbar spine surgery prior to the index surgery. Propensity score matching (based on age, sex, and follow-up time) was utilized to match two patients without prior surgery with each patient with a previous surgery. The primary outcome measure was the need for further lumbar spine surgery during the follow-up period, and the secondary outcome measures consisted of present-time patient-reported outcome measures (Oswestry Disability Index, EuroQol-5D) and present-time ability to carry out employment. RESULTS: Patients who received previous lumbar surgeries had a higher need for further surgery (44% vs. 28%, p = 0.009) and had a shorter time to further surgery than the propensity score-matched cohort (mean Kaplan-Meier estimate, 15.7 years vs. 19.8 years, p = 0.008). Patients with prior surgery reported inferior Oswestry Disability Index scores (13.7 vs. 8.0, p = 0.036). and EQ-5D scores (0.77 vs. 0.86, p = 0.01). In addition, they had a higher frequency of receiving lumbar spine-related disability pensions than the other patients (12% vs. 1.9%, p = 0.01). CONCLUSIONS: Patients with previous lumbar surgery had inferior long-term outcomes compared to patients without prior surgery. However, the vast majority of these patients improved quickly after the index surgery. Furthermore, the difference in the patients' reported outcomes was small at the long-term follow-up, and they reported high satisfaction with the results of the study surgery. Hence, surgery for these patients should be considered if surgical indications are met, but special care needs must be accounted for when deliberating upon their indications for surgery.