Background: Reduced sensation frequently occurs after reduction mammaplasty. However, the degree of sensation can vary among individuals. The aim of this study is to assess how body mass index (BMI) and weight of breast tissue excised during reduction mammaplasty affects postoperative sensation.

Methods: Patients undergoing reduction mammaplasty with superomedial or superior pedicle and Wise pattern incisions were prospectively followed. One month after surgery, neurosensory testing was completed using a pressure-specified sensory device to record sensation on a scale from 0 to 100, where higher values indicate greater sensitivity. An average sensation score was calculated per breast from 9 breast regions. Patient demographics, BMI, and weight of breast tissue excised were recorded. Linear regression analysis was run to predict postoperative sensation from BMI, specimen weight, and ratio of BMI to specimen weight. Student t-test were used to detect differences between BMI groups (BMI <30 vs. BMI >30) and specimen weight (weight <1,000 g vs. weight >1,000 g).

Results: Sensory testing was completed on 28 breasts in 14 patients. Multiple linear regression analysis revealed that specimen weight (t=-2.59, p=0.02) was a significant predictor of postoperative sensation, but BMI was not (t=-0.32, p=0.75). The ratio of BMI to specimen weight was also a significant predictor of postoperative sensation (t=2.65, p=0.01). Our result is robust to the normal assumption. Even using nonparametric Spearman’s coefficient test, the results remain significant. The Spearman’s Correlation coefficient was -0.46 for specimen weight (p=0.01) and 0.49 for ratio of BMI to specimen weight (p=0.01). A t-test revealed a significant difference in average postoperative sensation between patients with less than 1,000 g excised (68.39 ± 15.47) and 1,000 g or more excised (53.17 ± 18.93) (p=0.03). There was no difference between average postoperative sensation in obese (64.97 ± 16.74) and non-obese patients (60.28 ± 20.07) (p=0.51).

Conclusions: This study revealed that specimen weight was a predictor for postoperative sensation, with more tissue excised resulting in worse sensation. The ratio of BMI to specimen weight was also found to be a significant predictor, suggesting that specimen weight is predictive of sensation irrespective of BMI. These parameters can guide preoperative counseling and may suggest a benefit for nerve reinnervation in certain groups that need a larger amount of breast tissue excised during reduction. Future work will investigate how BMI and specimen weight affect long-term sensation following mammaplasty.