Lateral and Inferior Implant Malposition in Prosthetic Breast Reconstruction: Incidence and Risk Factors

Abstract

Background: Implant malposition is one of the most common causes for revision after prosthetic breast reconstruction. There is a paucity of research on the incidence, etiology and risk factors for implant malposition in this setting. Methods: Retrospective review of a single surgeon’s prosthetic breast reconstructions was performed. Variables collected included age, BMI, radiation, chemotherapy, implant characteristics and malposition location (inferior or lateral). Binary logistic regression identified risk factors for malposition. Chi-square test assessed malposition rate as a function of implant volume to BMI subgroups. Results: Of 836 breasts, 82 (9.8%) exhibited implant malposition. Risk factors for any malposition were older age (OR 1.05, 95% CI 1.02-1.07), BMI<25 (OR 1.64, 95% CI 1.00-2.70) and bilateral reconstruction (OR 13.41, 95% CI 8.50-21.16). Risk factors for inferior malposition were older age (OR 1.04, 95% CI 1.01-1.06), BMI<25 (OR 3.43, 95% CI 1.88-6.26) and bilateral reconstructions (OR 11.50, 95% CI 6.79-19.49), while risk factors for lateral malposition were only older age (OR 1.05, 95% CI 1.02-1.08) and bilateral reconstructions (OR 7.08, 95% CI 4.09-12.26). Post-mastectomy radiation was protective against lateral malposition (OR 0.30, 95% CI 0.10-0.88). Stratification by implant volume and BMI demonstrated patient subgroups with distinct patterns of malposition (incidence 0.0% versus 10.9%, P = 0.001). Conclusions: This is the first study to identify risk factors for implant malposition after prosthetic breast reconstruction. Different risk factors contributed to malposition in different directions. The effect of implant size on malposition was mediated through BMI, highlighting the interplay of implant and patient characteristics with respect to malposition.

Patient Outcomes after Fat Grafting to the Radiated Chest Wall before Delayed Two-stage Alloplastic Breast Reconstruction

“…The rate of capsular contraction in the literature without fat grafting in the setting of PMRT and alloplastic reconstruction ranges from 12.5% to 53.3%. 22 Our reported implant malposition rate of 9.8% is similar to implant malposition rates in breast reconstruction without radiation quoted from 5% to 9.8% 23 , 24 and much lower compared with a malposition rate of 27.8% in the context of radiation. 25 …”

Commentary on: The Best Under Stress: An Analysis of Breast Tissue Expander Response to External Forces

“…Studies have demonstrated that the incidence of implant displacement in prepectoral reconstruction is ∼5.9% 2 and in subpectoral breast reconstruction is ∼9.8%. 3 As a means of overcoming these compressive forces, overfilling of tissue expanders was often necessary with subpectoral placement. These compressive forces were exacerbated following radiation therapy due to the progressive fibrosis of the pectoralis major muscle and the overlying adipocutaneous layer.…”