[Myosonographic and electromyographic (EMC) evaluation of donor-site morbidity after microsurgical TRAM flap]

Due to improved microsurgical techniques the role of autologous breast reconstruction is expanding. One reason is the decreased donor-site morbidity compared to other techniques. Perforator based flaps (DIEP flaps) seemingly decrease the damage of the abdominal wall due to flap harvesting. However, complication rate in perforator flaps is still considered to be higher than in TRAM flaps. Additionally, operating time is increased due to the meticulous microsurgical dissection of perforators. To evaluate whether donor-site morbidity is caused by harvesting a part of the rectus muscle (as TRAM flaps), 15 patients after unilateral muscle sparing TRAM flap underwent EMG and myosonographic examination of the rectus muscle. EMG is the only technique to assess the muscle functionally, as the electrical activity of the muscle is recorded, and motor unit recruitment can be shown. EMG examination clearly revealed that harvesting of a muscle sparing TRAM flap did not impair the rectus muscle compared to the intact contralateral muscle. However, motor units were enlarged. Myosonography (in contrast to MRI) detected particular damage of isolated muscle fibres indicating nerve-related muscle changes. Taking all findings together, harvesting of a part of the rectus muscle shows a distinct damage to the muscle. The muscle however still acts functionally. This indicates that problems after harvesting a TRAM flap (bulging, hernias etc.) are not due to the partial removal of muscle, but due to the general dissection of the abdominal wall, as seen in other abdominal operations.