Pectoralis Major Muscle Morbidity After Submuscular Silicone-based Breast Reconstruction: A Systematic Review.

Silicone implants or tissue expanders placed under the pectoralis major (PM) muscle are often used for breast reconstruction. However, the disruption of PM insertions, which is often an inevitable part of the surgical procedure, is known to cause PM morbidity and, subsequently, problems with the use of the ipsilateral arm. In this systematic review, we present current knowledge regarding the effect of submuscular silicone-based breast reconstruction on the function of PM and the ipsilateral arm. A search of the relevant English literature was performed through PubMed and ten eligible studies were identified. Articles reporting breast augmentation were accepted as the techniques of implant insertion are similar to reconstruction. Questionnaires reporting the status of the arm, analysis of the range of motion of the shoulder with 3-D video, isometric or isokinetic dynamometry, ultrasound shear-wave elastography, volumetric MRI, electromyography and light and electron microscopy of the PM fibers were used for the assessment of PM and arm status. The insertion of implants under the PM, especially when combined with dissection of some of its insertions, seems to be associated with measurable abnormal microscopic, imaging, and dynamometric findings. However, the intact part of the muscle and possibly other nearby muscular structures are able to compensate for the lost part of PM. Thus, the insertion of implants fully or partially under the PM seems to have no or little effect on the function of the ipsilateral upper limb in daily life.