Anatomical and Functional Recovery of Neurotized Remnant Rectus Abdominis Muscle in Muscle-Sparing Pedicled Transverse Rectus Abdominis Musculocutaneous Flap

Abstract

Background Pedicled transverse rectus abdominis musculocutaneous flaps typically sacrificethe entire muscle. In our experience, the lateral strip of the rectus abdominis muscle can bespared in an attempt to maintain function and reduce morbidity. When the intercostal nervesare injured, muscle atrophy appearswith time. The severed intercostal nervewasreinserted intothe remnantlateralstrip ofthe rectus abdominismuscle to reducemuscle atrophy.Methods The authors retrospectively reviewed 9 neurotized cases and 10 non-neurotizedcases. Abdominal computed tomography was performed to determine the area of the rectusmuscles. Electromyography (EMG)was performed to check contractile function ofthe remnantmuscle. A single investigator measured the mean areas ofrandomly selected locations(secondlumbarspine) using ImageJsoftware in a series of 10 cross-sectionalslices. We compared theHounsfield unit(HU) pre- and postoperatively to evaluate regeneration quality.Results In the neurotization group, 7 of 9 cases maintained the mass of remnant muscle.However, in the non-neurotization group, 8 of 10 losttheir mass. The number oftotally atrophied muscles in each of the two groups was significantly different (P= 0.027). All of theremnantmusclesshowed contractile function on EMG. The 9 remaining remnantrectus abdominis muscles showed declined the HU value after surgery but also within a normal range ofmuscle.Conclusions Neurotization was found to be effective in maintaining the mass of remnantmuscle. Neurotized remnant muscle had contractile function on EMG and no fatty degeneration byHUvalue.

Keywords

• Rectus abdominis
• Nerve transfer
• Electromyography
• Multidetector computed tomography