Extent of Fatty Infiltration of Lumbar Paraspinal Muscles as a Proxy for Frailty and Its Relationship with Perioperative Outcomes in Patients Undergoing Elective Spinal Surgery.

Study DesignRetrospective Cohort Study.ObjectivesThe purpose of this study was to identify the role of lumbar paraspinal muscle fatty infiltration using the Goutallier classification in predicting perioperative outcomes following elective lumbar surgery.MethodsA retrospective review was conducted on patients who underwent elective one- or two-level lumbar decompressions or instrumented fusions for degenerative pathology at a single institution over a 3 year period. Patients were stratified by procedure type. Data included demographics, perioperative outcomes, and the 5-item Modified Frailty Index (MFI-5). Fatty infiltration was graded at L4-5 using the Goutallier classification (intraclass correlation coefficient = 0.908). Opportunistic osteoporosis screening used computed tomography-based Hounsfield units (HU) at L1-2. The relationships between Goutallier grade, demographics, MFI-5 score, and postoperative outcomes were analyzed using Chi-squared analyses, Fisher's exact test, Analysis of Variance, and multivariable logistic and linear regression.ResultsIn total, 314 patients met the inclusion criteria. Mean age was 68.9 ± 8.6 years; mean Goutallier score was 2.2 ± 1.1 and MFI-5 was 1.3 ± 1.0. Goutallier score significantly correlated with age, American Society of Anesthesiologists grade, steroid use, MFI-5, discharge disposition, and 180 day complications and reoperation. Subgroup analyses revealed differing associations between Goutallier score and comorbidities/outcomes across procedure types. Multivariable regression confirmed Goutallier score as predictive of 180 day complications, reoperation, non-home discharge, and frailty.ConclusionGoutallier score is a predictive marker of frailty and postoperative outcomes in lumbar spine surgery. Goutallier classification is an effective tool that can aid in risk stratification for patients undergoing lumbar spinal surgery.