Clinical and radiographic outcomes after lateral lumbar interbody fusion in patients older than 75 years

Abstract

OBJECTIVE There is an increasing need for optimal surgical techniques for older patients with degenerative spine disease. The authors evaluated perioperative complications and clinical and long-term radiographic outcomes in patients older than 75 years after lateral lumbar interbody fusion (LLIF) for degenerative spine disease. METHODS The authors conducted a single-center, retrospective case series of consecutive patients older than 75 years who underwent single-level or multilevel LLIF between January 1, 2017, and December 31, 2022. Postoperative transient neurapraxia or permanent neurological deficits were documented. Outcomes were assessed using patient-reported outcome scales. Bone density was measured at the femoral neck and L1 vertebra. Sagittal vertical axis (SVA), segmental lordosis (stratified by level), lumbar lordosis (LL), pelvic incidence–LL mismatch, sacral slope, and pelvic tilt were measured on upright radiographs. Fusion status was assessed using the Lenke classification system on CT scans obtained at least 1 year postoperatively. Clinical and radiographic outcomes were assessed using paired t-tests and multivariable regression. The values for continuous variables are expressed as the mean (SD). RESULTS Fifty-two patients (mean age 78.6 years; range 75–87 years) met the inclusion criteria; 94 levels were treated in these patients, and the mean follow-up was 12.2 (6.3) months. All outcome measures showed significant improvement at latest follow-up, including the mean changes in scores on the Oswestry Disability Index (−14.5 [17.5]); visual analog scale (VAS) for back pain (−2.2 [3.8]); and VAS for leg pain (−3.3 [3.9]) (all p < 0.001). Age was not associated with perioperative outcomes, except change in VAS score for back pain (r = 0.4, p = 0.03). One year postoperatively, 88% of levels (52 of 59 levels in 31 patients available for follow-up) demonstrated bony fusion. Patients experienced significant improvements in the mean change in SVA (−1 [2.7] cm); segmental lordosis (5.9° [4.1°]); LL (5.3° [9.8°]); and pelvic incidence–LL mismatch (−2.9° [6.4°]) (all p < 0.01). Cage subsidence was observed in 7 of 94 levels (7%). On multivariable regression analysis, increasing age was a significant predictor of reduced radiographic correction with respect to the change in SVA (β 0.43; 95% CI 0.10–0.77; p = 0.01) and the change in LL (β −1.18; 95% CI −2.12 to −0.23; p = 0.02). CONCLUSIONS This series demonstrates safe clinical outcomes and stable long-term radiographic outcomes in patients older than 75 years undergoing LLIF for degenerative lumbar spine disease.