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

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.