Outcomes After 1- or 2-level Minimally Invasive Decompression for Patients with High 5-Item Modified Frailty Index.

Study design/setting: Retrospective review of prospectively collected data.

Objective: To evaluate the efficacy of the 5-factor modified frailty (mFI-5) index in predicting patient outcomes and recovery kinetics in minimally invasive decompression (MI-decompression) for the treatment of degenerative lumbar disorders.

Summary of background data: The mFI-5 index, which measures frailty or the age-associated decline in recovery ability following a significant stressor, has risen as a patient-specific indicator for postoperative morbidity and mortality. However, no studies have evaluated the utility of frailty in predicting outcomes after MI-decompression for degenerative lumbar pathologies.

Methods: Patients who underwent primary one- or two-level MI-Decompression for degenerative lumbar spine conditions were included. Patients were stratified into three groups: non-frail (mFI-5=0), moderately frail (mFI-5=1), and severely frail (mFI-5≥2). Outcome measures included surgical details, complications, return to activity, and patient reported outcome measures at preop and ≥6 months postop.

Results: A total of 956 patients were included, 438 non-frail, 418 moderately frail, and 100 severely frail. Frail patients (mFI-5 ≥1) were older (P<0.001), had greater BMI (P=0.047), elevated CCI (P<0.001), and greater percentages of ASA class ≥3 (P<0.001). Higher severities of frailty were associated with longer operative times (P<0.001) and lengths of stay (P<0.001), while blood loss was similar. Frail patients demonstrated worse preoperative symptoms, including ODI (P=0.019), VAS-back pain (P=0.019), and SF12-PCS (P=0.015), which continued postoperatively, including ODI (P=0.014) and SF12-PCS (P<0.001). The magnitude of improvement between outcome metrics was comparable at ≥ 6-month follow-up. Return to activities-driving, working, and discontinuation of narcotics-as well as all complication categories-intraoperative, in-hospital, and postoperative-were similar across all patients.

Conclusions: MI-decompression provides comparable symptom relief and postoperative recovery, even among patients with significant frailty that could limit their ability to withstand the stresses of spine surgery.