The Inframammary Fold As A Dynamic Structure: Identifying Changes After Weight Loss and Implications for Breast Rejuvenation Surgery

Goals/Purpose: Aesthetic enhancement of the breast by augmentation alone or in combination with mastopexy is dependent on centered placement of the prosthesis under the breast’s footprint.  Typically this is achieved by placement of the implant in a sub-pectoral position, with varying degrees of muscle coverage to allow proper positioning in relation to the inframammary fold (IMF).  This method is effective for aesthetic enhancement only when the IMF is positioned at or near the inferior insertion of the pectoral fibers.  However, the IMF is a dynamic structure that undergoes a downward-oriented migration through the process of aging, pregnancy, and massive weight loss.  Its native position in relation to the thoracic wall varies by race and body structure, but there is a distinct transformation that occurs as a direct result of these factors.  This new position relative to the fixed Pectoralis major muscle should thereby influence the decision-making process regarding plane of implant placement to achieve a properly proportioned and augmented breast.

Methods/Technique: One hundred women requesting breast lift, augmentation, or both were recruited for this study.  This cohort was divided into two groups based on maintenance of weight.  Fifty patients with absolute weight loss greater than 30 pounds were compared to fifty patients with no weight loss.  The distances from the clavicle to the IMF and clavicle to the costal margin along the mid-clavicular line were obtained by pre-operative measurement. 

Results/Complications: The IMF was recorded as a percentage of the distance from the clavicle to the costal margin along the mid-clavicular line for both groups.  The data was analyzed with an unpaired T-test with a two-tailed distribution.  The non-weight loss group (Group 1) demonstrated IMFs at 77.3% the distance from the clavicle to the costal margin.  The weight loss group (Group 2) demonstrated the IMFs at an average of 95.0% the distance.  These findings of a mean difference of 17.7% are statistically significant (p<0.0001) with a 95% Confidence Interval of 14.0% - 21.4%.  This translates to an absolute difference of 5.5 centimeters.

Conclusion: The data obtained demonstrates a clear effect of weight loss on the position of the IMF relative to the thoracic wall.  Because the Pectoralis major muscle is a fixed structure, placement of an implant in a sub-pectoral plane may not necessarily coincide with the anatomical breast footprint.  Conversely, proper implant placement in relation to the IMF may not necessarily be covered by any meaningful amount of Pectoral muscle.  Our intention is to demonstrate that the relative position of the IMF is variable and dynamic, and should strongly influence the surgical decision-making process to achieve the greatest outcomes in breast enhancement surgery.