The Influence of Frailty and Biological Age on Outcomes of Adult Spinal Deformity Surgery in Elderly Adults: A Systematic Review and Meta-analysis

Introduction: Adult spinal deformities (ASDs) present a growing healthcare challenge due to their high prevalence and significant impact on quality of life. Surgical intervention in elderly populations introduces unique risks due to age-associated comorbidities and the complexity of deformity correction. Recent evidence suggests that frailty and biological age could offer more accurate predictors of postoperative outcomes than chronological age alone, yet the specific roles of these factors remain inadequately examined in the context of spinal deformity surgeries. This study aims to review the influence of frailty and biological age on outcomes of ASD surgery.

Methods: Based on the PRISMA guideline, a systematic search was conducted across Embase, Scopus, Web of Science, and PubMed up until September 15th, 2024, using the relevant key terms.

Results: Among 611 recruited records, 11 studies met the inclusion criteria. This study includes 4042 patients aged 59-81 years, using different frailty indexes such as Miller, Edmonton, and modified frailty index and follow-up ranges were from one month to three years. Frail patients had significantly more blood loss and complications (P = 0.0001). There were no significant differences regarding surgery time, length of ICU stay and hospitalization, and ambulation day between frail and non-frail patients. In addition, there were no significant differences regarding surgery outcomes such as sagittal and coronal vertical axis, lumbar lordosis, pelvic tilt, and T1 pelvic angle between frail and non-frail patients. The mean difference of the after surgery and before surgery in Oswestry Disability Index and Scoliosis Research Society 22 questionnaire, were not statitstically significant in frail vs non-frail patients.

Conclusion : While frailty significantly increases perioperative risks, including blood loss and complication rates, it does not appear to impact key surgical or functional outcomes such as spinal alignment, hospital stay, or recovery milestones in elderly patients undergoing ASD surgery. These findings underscore the need to consider frailty as a predictor of short-term surgical risk rather than long-term outcomes, highlighting the potential for a more nuanced approach in managing and counseling frail patients in this population.