Age diversity among older surgically treated patients with lumbar spinal stenosis: a retrospective comparative study of early and late older adults

Background: At present, the threshold defining older adults is 65 years, and this classification has been widely accepted globally. However, with the extension of both life expectancy and healthy life expectancy, there is a need to reconsider this age-based definition. This study compared the characteristics and surgical outcomes of older patients with lumbar spinal stenosis (LSS) between the early and late stages to clarify age diversity in this population. Methods: Data collected from consecutive patients aged ≥ 65 years who underwent LSS surgery were retrospectively reviewed. All participants completed the Zurich Claudication Questionnaire, Japanese Orthopaedic Association Back Pain Evaluation Questionnaire (JOABPEQ), and 25-Question Geriatric Locomotive Function Scale preoperatively as well as 6 and 12 months postoperatively. Frailty was evaluated using the 11-point modified frailty index. Polypharmacy was defined as the concomitant use of at least six drugs. Results: In total, 311 older patients with LSS were enrolled. Among them, 136 patients younger than 75 were categorized into the E group, and 175 patients aged 75 and older were categorized into the L group. Baseline characteristics, including frailty and polypharmacy, significantly differed between the groups. The frequency of effective case of surgical treatment on JOABPEQ was significantly lower for walking ability in the L group. At 1 year after surgery, the incidence of non-improvement in locomotive syndrome stages was higher in the L group than in the E group (relative risk = 1.38, 95% confidence interval [CI] = 1.08–1.78). In addition, when the L group was further divided into three subgroups based on age, the relative risk was 1.32 (95% CI = 0.99–1.76) for patients aged 75 to < 80, 1.42 (95% CI = 1.07–1.88) for those aged 80 to < 85 years, and 1.68 (95% CI = 1.16–2.45) for those aged ≥ 85. Conclusions: Significant differences were observed in baseline characteristics and postoperative improvement of walking ability and locomotive syndrome based on age among older patients with LSS. Our findings underscore the significant age diversity among older adults, highlighting the necessity of considering each patient in a more nuanced age-specific manner rather than adopting a one-size-fits-all approach.