Neurovascular anatomy of sartorius muscle flaps: implications for local transposition and facial reanimation.

BACKGROUND: The sartorius muscle is a superficial muscle of the thigh that possesses highly suitable qualities for many uses in local transposition and free muscle transfer. However, a paucity of description of the neurovascular anatomy of the sartorius has contributed to its infrequent use in these roles. METHODS: Both human and canine studies were undertaken to delineate the neurovascular anatomy of the sartorius and to determine the role for surgical delay clinically. Fifty-five human cadaveric sartorius muscles and 30 canine cadaveric sartorius muscles underwent angiographic and dissection studies, and the location and course of the vessels and nerves supplying sartorius are described. A subsequent study was undertaken in two live canines in which the vascular supply to the sartorius was evaluated before and after surgical delay. RESULTS: The sartorius is supplied by an average of six or seven vascular pedicles, the size, location, and course of which are described. The nerve supply to the sartorius enters at its proximal end and uniformly arises from a branch of the femoral nerve. Variations in branching patterns and course of nerves and vessels are described. Living canine studies demonstrated the dilatation of intramuscular vessels following surgical delay, with the contrast injection of a single remaining vascular pedicle shown to vascularize the entire length of the sartorius muscle. CONCLUSIONS: The sartorius is highly suitable for local transposition and free muscle transfer for facial reanimation. The neurovascular anatomy is reliable, and the use of surgical delay can augment its vascular supply and increase the arc of rotation for local transposition.

The DIEA branching pattern and its relationship to perforators: the importance of preoperative computed tomographic angiography for DIEA perforator flaps.

BACKGROUND: Abdominal donor-site flaps based on the deep inferior epigastric artery (DIEA) are the most common flaps used in autologous breast reconstruction. With significant variation in the vascular anatomy of the DIEA, preoperative imaging is desirable. Computed tomographic angiography, recently described for this purpose, uniquely demonstrates the branching pattern of the DIEA. The authors sought to correlate the DIEA branching pattern to the location and course of perforators as a preoperative planning tool for perforator flaps. METHODS: Forty-five cadaveric hemi-abdominal walls were used for contrast injection of the DIEA with subsequent radiographic imaging. The branching pattern on radiography was thus correlated to the location and intramuscular course of perforators, from the main DIEA trunk to the point of the penetrating rectus sheath. RESULTS: The DIEA branching pattern correlated closely with the course of perforators. A bifurcating (type II) branching pattern demonstrated a reduced transverse distance traversed by each perforator, whereas a trifurcating (type III) branching pattern demonstrated significantly greater transverse distances (p = 0.0002). Type I vessels were intermediate. Vessel branching type, however, displayed no significant correlation with the number of perforators (p = 0.56). CONCLUSIONS: The distances traversed by perforators were significantly reduced with a bifurcating branching pattern of the DIEA, particularly those originating from the lateral branch, and were greatest with a trifurcating branching pattern. Increased transverse distances correlate with greater rectus muscle sacrificed during perforator flap surgery. As computed tomographic angiography is the optimal modality for demonstrating this pattern preoperatively, the authors suggest its use for preoperative assessment in transverse rectus abdominis musculocutaneous and DIEA perforator flaps.

Raising perforator flaps for breast reconstruction: the intramuscular anatomy of the deep inferior epigastric artery.

BACKGROUND: The deep inferior epigastric artery (DIEA) perforator flap is used increasingly for breast reconstruction, preferred as a muscle-sparing operation over traditional transverse rectus abdominis musculocutaneous (TRAM) flaps. Complications related to the inclusion of rectus abdominis include abdominal wall weakness and a predisposition to ventral abdominal wall hernias. DIEA perforator flaps still present this complication, with clinical experience demonstrating frequent transection of rectus fibers during dissection of perforators. Despite this, published descriptions of the DIEA in the literature describe a "direct" course through rectus abdominis. This study interprets these clinical findings by analyzing the intramuscular course of the perforators. METHODS: The investigation was performed on 31 hemiabdominal walls from both fresh and embalmed cadavers, using a combination of dissection and radiography of multiple cross-sectional planes. Intramuscular distances were measured using the distances between entry and exit points of perforators from rectus abdominis muscle, allowing characterization of the intramuscular course. RESULTS: Substantial longitudinal (mean, 1.52 cm; range, 0.2 to 4.1 cm) and transverse (mean, 1.32 cm; range, 0.3 to 3.5 cm) distances were traversed by each of the 76 perforators within the muscle. CONCLUSIONS: A significant transverse distance was shown to be traversed by perforators, confirming the need for division of rectus abdominis fibers during operation. This information may help explain the clinical findings of abdominal wall morbidity following perforator flaps, and may pave the way for improved preoperative selection of patients for DIEA perforator flaps.