Body Mass Index Versus Body Composition for Risk Stratification in Craniofacial Surgery.

Accurate preoperative risk stratification is essential in craniofacial surgery, where complex procedures and prolonged recovery place significant physiological demands on patients. Body mass index (BMI) is commonly used in clinical practice due to its simplicity; however, its ability to predict surgical outcomes remains inconsistent. BMI does not distinguish between fat and lean mass, account for adipose distribution, or reflect functional and metabolic reserve. This can lead to variability in risk assessment. This is particularly evident in craniofacial surgery, where operative fields contain relatively limited adipose tissue, and outcomes may be more closely tied to wound healing capacity, nutritional status, and overall physiological resilience. Body composition offers a more detailed characterization of these underlying factors by quantifying skeletal muscle mass, adiposity, and their distribution. Emerging evidence demonstrates that body composition phenotypes, including sarcopenia, sarcopenic obesity, and metabolically abnormal normal-weight states, may be more consistently associated with perioperative complications, delayed recovery, and adverse functional outcomes than BMI alone. These relationships are especially relevant in vulnerable craniofacial populations. These consist of pediatric patients with high metabolic demands and oncologic patients at risk for malnutrition and muscle depletion. This review examined the limitations of BMI, outlines methods for assessing body composition, and synthesizes current evidence linking body composition to surgical outcomes, with a focus on its application in craniofacial surgery.