Analyzing the prognostic value of the 5-factor Modified Frailty Index in Patients Undergoing Deformity Correction Surgery for Adult Spinal Deformity

Introduction: The 5-factor modified frailty index (mFI-5) is used as a measure of frailty and as an independent predictor of adverse outcomes. Our study aims to validate the mFI-5 and analyze its effectiveness in predicting adverse outcomes in patients undergoing surgery for adult spinal deformity (ASD).

Methods: A retrospective review was performed for patients who underwent thoracolumbar ASD surgery (≥4 levels). Preoperative, intraoperative, and postoperative parameters were collected and analyzed by Chi-square test, Fisher's exact test, and linear regression.

Results: 215 patients including 70 males (32.6%) were included in the final analysis. The mean age of the cohort was 69.6 ± 8.20 years, and the average number of levels fused was 9.3 ± 2.77. Significant correlations between mFI-5 and comorbidity factors such as obesity class 2 (OR: 6.7, CI: 0.98-290, p< 0.05) and American Society of Anesthesiologists’ class 3 (OR: 3.2, CI: 1.36-7.55, p< 0.005) provided validation for the frailty index in assessing frailty. For intraoperative parameters, each unit increase in mFI-5 score was associated with a 13.0 minute increase in anesthesia duration (CI: 3.67-22.4, p< 0.01), as well as a 164 mL increase in estimated blood loss (CI: 35.3-292, p< 0.05). For postoperative parameters, each unit score increase in the mFI-5 was associated with a 7.34 hour increase in ICU length of stay (CI: 1.94-12.7, p< 0.01), 0.53 day increase in total length of stay (CI: 0.09-0.96, p< 0.05), and 0.42 day delay in initiation of walking following surgery (CI: 0.12-0.81, p< 0.01).

Conclusion : The mFI-5 is an effective indicator of frailty. It can be utilized to predict adverse outcomes which can assist in identifying ideal surgical and post-surgical management for frail patients undergoing ASD surgery.