No surgical site infections observed after lumbar unilateral biportal endoscopy: a multicenter retrospective series of 1566 patients

Background: Surgical site infection (SSI) remains a concern in spinal surgery despite advances in minimally invasive techniques. Unilateral biportal endoscopy (UBE) may reduce infection risk via limited tissue trauma and continuous saline irrigation, but its true SSI incidence remains unknown. Research question: This study aimed to assess the incidence of SSI after lumbar UBE procedures. Material and methods: This retrospective multicenter study included consecutive patients who underwent lumbar UBE for degenerative conditions between March 2022 and January 2025 in four French spine centers. Secondary outcomes included other complications and functional recovery. Results: Among 1566 patients (mean age 58 ± 16 years; 53 % male), indications included disc herniation (59 %) and spinal stenosis (39 %). Half received perioperative antibiotic prophylaxis. No SSI occurred within 90 days after UBE. One SSI was observed after a subsequent open revision with fusion, unrelated to the initial procedure. Other complications occurred in 15 % of patients, including dural tears (5 %) and reoperations (4 %), mainly for recurrent herniation. At 3 months, ODI improved from 46 ± 19 to 20 ± 18, with a minimal clinically important difference achieved in 72 % of cases. Discussion and conclusion: No SSI was identified after lumbar UBE in this large multicenter series. Continuous irrigation and minimal tissue trauma may confer a protective effect, supporting UBE as a safe minimally invasive approach with extremely low infection risk.