Reoperation rates and radiographic outcomes after short-segment standalone lateral lumbar interbody fusion for degenerative lumbar scoliosis.

BACKGROUND: Degenerative lumbar scoliosis (DLS) is a common condition in older adults, with prevalence increasing with age. When conservative measures fail, there are many surgical treatment options, from targeted decompression and fusion to long construct deformity surgery. Standalone lateral lumbar interbody fusion (SA-LLIF) may be a minimally invasive option to address discogenic pain and symptomatic foraminal stenosis at the apex levels; however, evidence regarding durability and radiographic outcomes remains limited. This study evaluated revision rates, radiographic outcomes, and predictors of revision surgery following 1- or 2-level SA-LLIF in patients with DLS.

METHODS: We retrospectively reviewed 108 patients with DLS and a preoperative lumbar Cobb angle ≥ 20° who underwent 1- or 2-level SA-LLIF at a single academic center. Radiographic parameters were assessed preoperatively, at the first postoperative radiograph (FPO), and at one year postoperatively (1YPO). Revision-free survival was analyzed using Kaplan-Meier methods, and predictors of revision surgery were evaluated using multivariable Cox regression.

RESULTS: The cohort had a mean age of 67.0 ± 11.9 years and 56.5% were female, with a mean follow-up of 4.8 ± 3.2 years. Twenty-five patients (23.1%) underwent revision surgery during follow-up, including 9 (8.3%) within the first 24 months. Among these early revisions, the most common indications were adjacent segment disease (n = 5, 55.6%) and residual stenosis (n = 4, 44.4%). Increasing age was the only independent predictor of revision (HR 1.06 per year, 95% CI 1.01-1.11; p = 0.013). Radiographically, Cobb angle improved significantly from 28.8° preoperatively to 21.9° at FPO and was maintained at 1YPO. LL increased modestly, while CVA and SVA remained largely unchanged.

CONCLUSIONS: In patients with DLS undergoing short-segment SA-LLIF, early revision rates were low, and cumulative revision rates over longer follow-up were comparable to those reported for posterior fusion procedures. Revision risk was primarily associated with age rather than radiographic parameters. These findings suggest that SA-LLIF may represent a less invasive option in carefully selected patients with DLS, providing sustained coronal correction and modest improvement in LL, without substantial changes in overall spinal balance.