Iatrogenic Symmastia: Causes and Suggested Repair Technique

Area of Science:

• Plastic Surgery
• Aesthetic Surgery
• Breast Augmentation Complications

Background:

• Iatrogenic symmastia, or "uniboob," can result from various factors during breast augmentation surgery.
• Commonly cited causes include over-dissection of the medial breast pocket, sternal fascia disruption, large implant diameter, and excessive dissection of pectoral muscle attachments.

Purpose of the Study:

• To investigate the primary risk factors contributing to iatrogenic symmastia.
• To test the hypothesis that subpectoral (submuscular) breast augmentation is the most frequent cause.

Main Methods:

• Retrospective chart review of 23 symmastia patients treated by a single surgeon (2008-2018).
• Survey of 91 American Society for Aesthetic Plastic Surgery (ASAPS) members regarding symmastia etiology and incidence.

Main Results:

• All 23 reviewed patients with symmastia had prior subpectoral breast augmentation.
• ASAPS survey: 91% of acquired symmastia consults involved patients with previous subpectoral augmentation.
• Most surveyed surgeons identified over-dissection of medial pectoralis muscle attachments as the main cause.

Conclusions:

• Pectoralis major sternal dehiscence during subpectoral breast augmentation is the leading cause of iatrogenic symmastia.
• Surgical repair necessitates securing Scarpa's fascia, reattaching the pectoralis major to the sternum, and avoiding further subpectoral implants.