Weighing the Merits of the Tri-Ponderal Mass Index for Predicting Complications after Mastectomy for Gynecomastia in Adolescents

Goals/Purpose: Pubertal gynecomastia is the abnormal enlargement of male glandular breast tissue during adolescence. Although pubertal gynecomastia may resolve spontaneously, it can also persist and cause psychological distress in young men. Obesity is a known risk factor for persistent gynecomastia; however, it is unclear if increasing body mass index (BMI) is associated with complications following mastectomy for gynecomastia in adolescents. The tri-ponderal mass index (kg/m³) has been reported as a better indicator of adiposity, cardiometabolic disease risk, and general physical fitness than BMI. Therefore, we conducted an analysis of adolescent patients to determine the relationship between tri-ponderal mass index, BMI, and postoperative complications. We hypothesized that tri-ponderal mass index was more closely associated with postoperative morbidity.

Methods/Technique: National Surgical Quality Improvement Project pediatric data was obtained from years 2012 – 2021. Included were male patients over 10 years old undergoing cosmetic mastectomy for gynecomastia designated by the following common procedural terminology codes: 19101, 19120, 19300, 19304, and/or 19318. Patients with a history of cancer, gender dysphoria, or congenital deformity were excluded.

Patient demographic data, intraoperative details, and 30-day postoperative complications were extracted. BMI was transformed into z-scores by age and sex. Surgical complications included surgical site infections and wound dehiscence. Readmission and reoperation details were also collected.

Descriptive statistics, Fisher’s exact tests, and multiple linear regression to predict odds of any complication were performed. Spearman correlations were calculated for BMI z-scores, tri-ponderal mass index, and the occurrence of medical and/or surgical complications, unplanned readmission, and unplanned reoperation. Obesity was classified as BMI ≥ 30.0 kg/m². Statistical analysis was conducted in RStudio 4.1.2.

Results/Complications: We included 504 patients undergoing cosmetic mastectomy for gynecomastia in our analysis. Mean age was 15.9 years (SD 1.5), mean BMI was 25.0 kg/m² (SD 7.1), and mean tri-ponderal mass index was 13.3 kg/m³ (SD 7.0). Patients undergoing mastectomy for gynecomastia were predominantly non-Hispanic (n=367, 72.8%) and White (n=223, 44.2%) or Black/African American (n=165, 32.5%). ASA Class II or higher was encountered in 243 patients (47.8%), and obesity was encountered in 110 patients (21.7%). Patients experienced 2 (0.4%) superficial surgical site infections, 6 (1.2%) unplanned readmissions, and 11 (2.2%) unplanned reoperations.

Patients with obesity were more likely to be Black/African American (p<0.001) or non-Hispanic (p=0.049), have clean/contaminated wounds (p<0.011), longer operative times (p<0.001), and higher rates of unplanned reoperation (p=0.031). Further details are summarized in Table 1.

Multiple linear regression showed that neither BMI [multivariate OR 1.05 (95%CI 0.95-1.15), p=0.355] nor tri-ponderal mass index [multivariate OR 1.09 (95%CI 0.96-1.25), p=0.226] were associated with higher odds of any complication. Spearman correlations showed that neither BMI z-score nor tri-ponderal mass index were correlated with medical or surgical complications, unplanned readmissions, or unplanned reoperations (p>0.05).

Conclusion: In the largest retrospective review of postoperative complications following mastectomy for gynecomastia in adolescents, we found no significant association between BMI, tri-ponderal mass index, and the development of any postoperative complication. Although the same findings are not generalizable to adults, our study suggests that neither obesity nor a high tri-ponderal mass index in an adolescent should be considered an exclusion criterion for operation based on risk of complications.