Surgical site infection following isolated lumbar discectomy increases odds of revision lumbar surgery within first 6 months, but not beyond

Abstract

BACKGROUND CONTEXTLumbar discectomy is a commonly performed surgery following which surgical site infection (SSI) may occur. Prior literature has suggested that, following SSI related to lumbar fusion, the rate of subsequent lumbar surgeries is increased over prolonged periods of time. This has not been studied specifically for lumbar discectomy. PURPOSETo define factors associated with SSI following lumbar discectomy and determine if subsequently matched cohorts with and without SSI have differential rates of subsequent lumbar surgery beyond irrigation and debridement (I&Ds) over time. STUDY DESIGN/SETTINGRetrospective cohort study. PATIENT SAMPLEAdult patients undergoing isolated primary lumbar laminotomy/discectomy were identified from the 2010-2021 M157PearlDiver database. Exclusion criteria included: age<18 years, preoperative diagnosis of infection, neoplastic, or traumatic diagnoses within 90 days prior to index surgery, additional spinal surgeries on the same day as lumbar discectomy, and not being active in the database for at least 90 days postoperative.From this study population, those who developed SSI were identified based on undergoing I&D within 90 days after surgery. Those with versus without SSI were then matched 1:4 based on age, sex, Elixhauser Comorbidity Index (ECI), and obesity. OUTCOME MEASURESFollowing initial I&D, incidence of revision lumbar surgery (revision lumbar discectomy, lumbar laminectomy, lumbar fusion) out to 5 years after lumbar discectomy. METHODSFollowing index isolated lumbar discectomy, those with versus without SSI requiring I&D were matched and compared for incidence of secondary surgery in defined time intervals (0–6 months, 6–12 months, 1–2 years, 2–5 years) using multivariable logistic regression, controlling for patient age, sex, ECI, and obesity status. RESULTSOf 323,025 isolated lumbar discectomy patients, SSI requiring I&D was identified for 583 (0.18%). Multivariable analysis revealed several independent predictors of these SSIs: younger age (odds ratio [OR] 0.85 per decade increase), ECI (OR 1.22 per 2-point increase), and obesity (OR 1.30).Following matching of those with versus without SSI requiring I&D, rates of subsequent surgery beyond I&D were compared. Those with SSI had significantly increased odds of lumbar revision in the first six months (OR 5.26, p<.001), but not 6–12 months (p=.462), 1–2 years (p=.515), or 2–5 years (p=.677). CONCLUSIONSOverall, SSI requiring I&D is a rare postoperative complication following lumbar discectomy. If occurring, subsequent surgery beyond I&D was higher in the first six months, but then not increased at subsequent time points out to five years.