Dynamic rectus abdominis muscle sphincter for stoma continence: an acute functional study in a dog model

Fecal stomal incontinence is a problem that continues to defy surgical treatment. Previous attempts to create continent stomas using dynamic myoplasty have had limited success due to denervation atrophy of the muscle flap used in the creation of the sphincter and because of muscle fatigue resulting from continuous electrical stimulation. To address the problem of denervation atrophy, a stomal sphincter was designed using the most caudal segment of the rectus abdominis muscle, preserving its intercostal innervation as well as its vascular supply. The purpose of the present study was to determine whether this rectus abdominis muscle island flap sphincter design could maintain stomal continence acutely. In this experiment, six dogs were used to create eight rectus abdominis island flap stoma sphincters around a segment of distal ileum. Initially, the intraluminal stomal pressures generated by the sphincter using different stimulation frequencies were determined. The ability of this stomal sphincter to generate continence at different intraluminal bowel pressures was then assessed. In all cases, the rectus abdominis muscle sphincter generated peak pressures well above those needed to maintain stomal continence (60 mmHg). In addition, each sphincter was able to maintain stomal continence at all intraluminal bowel pressures tested.     

Breast reconstruction with a transverse abdominal island flap

A rectus abdominis musculocutaneous island flap for breast reconstruction following mastectomy is presented. The vascular anatomy of the abdominal wall has been clinically studied in patients undergoing abdominal lipectomy. Cadaver dissections are shown, demonstrating the anatomy, arc of rotation, and design alternatives of the rectus abdominis flap. The surgical technique is demonstrated and representative patients are shown.     

Vaginal and pelvic reconstruction with distally based rectus abdominis myocutaneous flaps

This report introduces a new method of vaginal reconstruction using a single rectus abdominis myocutaneous flap based distally. Applications of this flap in reconstruction of major abdominal wall and pelvic defects, such as hemipelvectomies, are also described. The flap is designed to carry a paddle of upper abdominal skin on a distally based muscle and vascular pedicle. Advantages of this flap design are (1) the technique is straightforward and rapid, (2) flap viability is reliable, (3) the epigastric skin-fascial donor defect preserves the anterior rectus fascia distal to the linea semicircularis, which prevents hernia, (4) a large arc of rotation is provided, and (5) the epigastric donor site does not interfere with colostomy and urinary conduit stomas in the pelvic exenteration patient. We have done 11 vaginal reconstructions and 9 major pelvic defect reconstructions with this flap during the last 3 1/2 years. In these 20 patients, the only complications were two partial flap losses. No major flap losses or ventral hernias occurred.     

Skin recycling following neovascularization using the rat musculocutaneous flap model.

The recycling of a skin territory as part of a musculocutaneous flap despite prior division of existing musculocutaneous perforators or vice versa within an axial cutaneous flap using skin from a previous musculocutaneous flap may sometimes be done safely if an adequate time period has been allotted to permit sufficient neovascularization from adjacent tissues. In order to test this clinically observed phenomenon, a musculocutaneous flap model based on perforators from the rat rectus abdominis muscle was developed and observed to have complete reliability. Groups of five Sprague-Dawley rats each were sequentially utilized to prove that by a single week following creation of a rectus abdominis musculocutaneous flap adequate peripheral neovascularization would evolve to permit total viability of secondary axial epigastric cutaneous flaps incorporating the same skin that initially was the cutaneous portion of the muscle flap. The converse was also confirmed possible, again using sequential groups of five rats each, in that by 2 weeks the skin of an initial abdominal cutaneous flap could instead be safely transposed and nourished as part of a rectus abdominis musculocutaneous flap. The proposition concerning the reliable reuse of identical skin territories as part of disparate metachronous flap configurations appears to be valid.     

New microsurgical breast reconstruction using free paraumbilical perforator adiposal flaps

Pedicled transverse rectus abdominis musculocutaneous (TRAM) flaps have generally been used for bilateral breast losses. The major disadvantages of this method are the total or partial loss of the rectus abdominis muscles and various resulting postoperative complications, such as abdominal bulging and lumbar pain. With the recent development of perforator flaps and supermicrosurgery with anastomosis of 0.5-mm caliber vessels, these serious complications can be overcome with a paraumbilical perforator adiposal flap, without sacrificing the rectus abdominis muscle. The breasts of a 57-year-old woman who had undergone a bilateral subcutaneous mastectomy, including silicone prostheses, were repaired simultaneously with this new method using free paraumbilical perforator adiposal flaps. This new method of breast augmentation with a vascularized adiposal flap and without any muscle component is minimally invasive; its advantages are the preservation of the rectus abdominis muscles and the short time elevation for the adiposal flap.     

Analysis of fiber type transformation and histology in chronic electrically stimulated canine rectus abdominis muscle island-flap stomal sphincters

Dynamic skeletal muscle flaps are designed to perform a specific functional task through contraction and relaxation of their muscle fibers. The most commonly used dynamic skeletal flaps today are for cardiomyoplasty and anal or urinary myoplasty. Low-frequency chronic stimulation of these flaps enables them to use their intrinsic energy stores in a more efficient manner through aerobic metabolic pathways for increased endurance and improved work capacity. The purpose of this study was to (1) determine whether fiber type transformation from fatigue-prone (type II) muscle fibers to fatigue-resistant (type I) muscle fibers could be demonstrated in the authors' chronic canine stomal sphincter model where the rectus abdominis muscle was used to create a functional stomal sphincter, (2) assess whether there is any correlation between the degree of muscle fiber type transformation and the continence times, and (3) examine the long-term effects of the training regimens on the skeletal muscle fibers through histologic and volumetric analysis. Eight dynamic island-flap sphincters were created from a part of the rectus abdominis muscle in mongrel dogs by preserving the deep inferior epigastric vascular pedicle and the most caudal investing intercostal nerve. The muscular sphincters were wrapped around a blind loop of distal ileum and trained with pacing electrodes. Two different training protocols were used. In group A (n = 4), a preexisting anal dynamic graciloplasty training protocol was used. A revised protocol was used in group B (n = 4). Muscle biopsy specimens were obtained before and after training from the rectus abdominis muscle sphincter. Fiber type transformation was assessed using a monoclonal antibody directed against the fatigue-prone type II fibers. Pretraining and posttraining skeletal muscle specimens were examined histologically. A significant fiber type conversion was achieved in both group A and group B animals, with each group achieving greater than 50 percent conversion from fatigue-prone (type II) muscle fibers to fatigue-resistant (type I) muscle fibers. The continence time was different for both groups. Biopsy specimens 1 cm from the electrodes revealed that fiber type transformation was uniform throughout this region of the sphincters. Skeletal muscle fibers within both groups demonstrated a reduction in their fiber diameter and volume. Fiber type transformation is possible in this unique canine island-flap rectus abdominis sphincter model. The relative design of the flap with preservation of the skeletal muscle resting length and neuronal and vascular supply are important characteristics when designing a functional dynamic flap for stomal continence.     

Acute repair of a full-thickness right ventricular defect with a composite myofascial pedicle flap.

A full-thickness defect of the right ventricle presented acutely after mediastinitis and sternal dehiscence. This developed 29 days after bilateral internal mammary artery harvest for coronary artery bypass grafting. The defect was managed successfully with a pedicled left rectus abdominis muscle flap using an attached island of the anterior rectus sheath for endocardial lining. The vascular anatomic basis for viability of the rectus abdominis muscle flap after internal mammary artery harvest is derived primarily from musculophrenic, lumbar, lower sixth intercostal, and subcostal artery communications. In addition, the advantages of a myofascial pedicle flap for reconstruction of full-thickness cardiac defects are its ready availability and a strong anterior fascial sheath that can be used as a neoendocardial lining. The patient did well and remains asymptomatic after 3 years.     

Pfannenstiel incision as an alternative approach for harvesting the rectus abdominis muscle for free-tissue transfer

The rectus abdominis muscle has been one of the most commonly used donor tissues for free-flap reconstruction of defects in the extremities and in selected head and neck patients. The rectus abdominis has provided adequate soft-tissue mass with predictable anatomy and results for the majority of its applications in free-flap reconstruction. Harvesting of this muscle has typically been done through a paramedian or midline incision, which has left a lengthy notable scar on a patient's abdomen. To avoid the late aesthetic deformity associated with this typical approach for the rectus abdominis, we began harvesting the muscle through a Pfannenstiel incision. Patients were initially selected based on young age and limited soft-tissue requirements. With additional experience, this technique was extended to include all healthy patients regardless of age. Also, soft-tissue limitations no longer became an issue, as we learned the entire rectus abdominis muscle could be harvested from this approach. An extended Pfannenstiel incision was made from the ipsilateral anterior superior iliac spine to the lateral border of the contralateral rectus abdominis. A superiorly based flap was raised to expose the full length of the anterior rectus sheath from pubis to costal margin. In our earlier patients, a periumbilical incision was made for presumed easier access, but we discovered this was an unnecessary maneuver. With the anterior sheath fully exposed, the muscle was harvested and the sheath repaired in a routine manner. The elevated abdominal flap was returned to its anatomic position and closed over a suction drain. Since 1993, 10 patients have undergone a Pfannenstiel approach for harvesting of the rectus abdominis muscle. The mean age was 16. The areas requiring coverage included a traumatic elbow defect, seven traumatic lower extremity defects, one lower extremity sarcoma defect, and one lower extremity septic joint defect. Mean follow-up for these patients was 12 months. There were no flap failures. One patient developed an arterial thrombosis on postoperative day 5 and was treated with successful revision. There were no abdominal wall complications. Cosmesis was judged as good in all patients. We would recommend avoiding this approach in heavy or moderate smokers, diabetic patients, and patients with significant obesity. The Pfannenstiel approach to the rectus abdominis muscle has allowed for complete harvest of the muscle, improved aesthetic results compared with alternative techniques, and avoidance of donor-site morbidityin healthy patients.     

TRAM flap safety optimized with intraoperative Doppler

Anatomic studies have clearly documented the variable position of the deep superior epigastric vessels in the rectus abdominis muscle. In our opinion, only that part of the rectus abdominis muscle containing the vascular pedicle should be transposed with the TRAM flap. The Doppler probe provides a simple method of identifying the dominant intramuscular vascular axis. It consistently alerts the surgeon to any unusual position of a vessel at the costal margin or within the rectus abdominis muscle. This knowledge enables a conservative yet safe dissection of the vascular pedicle, rectus abdominis muscle, and its sheath. This in turn will enable a competent abdominal closure. The Doppler technique is safe, simple, quick, noninvasive, familiar to most surgeons, and applicable to all patients.     

The external oblique flap for reconstruction of the rectus sheath.

Despite the availability of synthetic materials and distant fascial flaps, primary closure of ventral abdominal defects with contiguous tissues remains the preferred solution. Increased experience with such defects in the lower abdomen, particularly at the time of bilateral rectus muscle transposition, led in 1985 to the investigation of an external oblique abdominis flap for closure of the anterior rectus sheath. From October of 1985 to October of 1990, 33 patients underwent repair of bilateral lower rectus abdominis defects with the help of bilateral external oblique flaps. Each of the patients had undergone synchronous chest or breast reconstruction using a transverse rectus abdominis musculocutaneous flap including bilateral rectus muscle pedicles. Although all patients in this study had undergone double-pedicle rectus muscle procedures, not all patients having had double-pedicle rectus muscle procedures required this maneuver. External oblique flaps were performed at the time of rectus sheath repair only if fascia could not be approximated without tearing. After closure of the bilateral paramedian defect, synthetic mesh overlay was added only if the direct closure still appeared excessively tight. At the time of advancement of the external oblique muscle and fascia, the internal oblique abdominis muscle and lateral cutaneous nerve of the thigh were preserved. Of the 33 patients who underwent this procedure, 7 required the addition of mesh overlay. Thirty-two patients healed uneventfully with a remarkably solid ventral abdominal wall. One patient developed an early postoperative hernia subsequent to a major and prolonged abdominal-wall infection and abscess. Patient follow-up ranged from 1 to 36 months, with a mean of 12 months.(ABSTRACT TRUNCATED AT 250 WORDS)     

Immediate reconstruction of the penis using an inferiorly based rectus abdominis myocutaneous flap

A new method for reconstruction of the penis using an inferiorly based rectus abdominis myocutaneous flap is described that seems to be particularly suitable for immediate one-stage reconstruction. Function of the residual portion of rectus muscle is preserved, and the abdominal wall is not significantly weakened.     

The extended vertical rectus abdominis myocutaneous flap for breast reconstruction

The extended vertical rectus abdominis myocutaneous flap has been used in 34 patients for breast reconstruction after radical mastectomy. This flap can reconstruct a large ptotic breast mound and fill the infraclavicular and axillary areas. The operative technique and a discussion of the method are presented. There are several advantages to the extended vertical rectus abdominis myocutaneous flap. First, the main advantage of this flap is its reliable vascular supply, which can reach to the infraclavicular and axillary areas. Second, the large volume of this flap can reconstruct the large ptotic breast, fill the infraclavicular hollow, and create an axillary fold. Third, no lower abdominal wall hernias have developed, and use of alloplastic abdominal wall reinforcement is not necessary. Finally, the simultaneous beneficial effect of horizontal abdominoplasty, which further enhances the patient's body image by narrowing the waist, is unique to this vertical abdominal flap. The disadvantages of this flap include (1) the midline abdominal scar, (2) an umbilical scar on the reconstructed breast, and (3) in principle, inappropriateness for the patient who desires pregnancy postoperatively.     

The segmental rectus abdominis free flap for ankle and foot reconstruction.

The reconstruction of soft-tissue defects of the ankle and foot usually requires free-tissue transfer. Although certain local flaps have been described for the reconstruction of these injuries, their utility may be compromised by significant crush injury or the size and location of the defect. Part of the rectus abdominis muscle, the segmental rectus abdominis free flap, is ideally suited for this use because of the muscle's versatility, reliability, and negligible donor deformity when harvested through a low transverse abdominal incision. Seven patients reconstructed with this flap are presented, and the technique is discussed. All patients have been successfully reconstructed with preservation of the ankle and foot. At present, all patients are fully or partially weight-bearing. The segmental rectus abdominis free flap is recommended for the reconstruction of such wounds.     

Arteriovenous shunting and regional blood flow in myocutaneous island flaps: an experimental study in pigs

In eight pigs, total blood flow, regional capillary blood flow distribution, and arteriovenous (AV) shunting were studied during the first 4 postoperative hours after elevation of a myocutaneous rectus abdominis island flap. Capillary blood flow and AV shunting were measured using radioactive microspheres before flap creation and 1 and 4 hours after surgery. Total blood flow, measured continuously as venous outflow, increased in the first postoperative hour (p less than 0.05). Elevation of the flap caused a slight decrease in skin capillary blood flow (p less than 0.05), whereas muscular capillary blood flow increased (p less than 0.01). AV shunting accounted for 50 percent of the total flap blood flow, whereas it was negligible in the abdominal wall prior to flap elevation. Thus stalk blood flow, skin appearance, and skin temperature may be poor indicators of nutritional capillary perfusion. However, the clinical and nutritional consequences of these findings remain to be established.     

Small intestinal submucosa in abdominal wall repair after TRAM flap harvesting in a rat model

The strength of porcine small intestinal submucosa in abdominal wall repair after transverse rectus abdominis myocutaneous flap harvesting was examined in a rat model. Changes in the levels of selected molecular markers of inflammation after small intestinal submucosa implantation were also studied. Eighty-three rats were divided into three groups. In experimental group I, an abdominal wall defect created by removal of the rectus abdominis muscle was repaired with placement of a 1.5 x 5-cm2 patch of small intestinal submucosa. In experimental group II, the muscle defect was repaired with a combination of small intestinal submucosa patch placement and fascial closure. In the control group, the defect was repaired with direct fascial closure. At postoperative times of 3 days, 2 weeks, 1 month, and 2 months, the muscle tissues adjacent to the abdominal wall repair site were subjected to biopsies for assessment of inflammation markers. Full-thickness sections of the abdominal wall from the repair site in each animal were removed for tensile strength testing and histological examinations. The results demonstrated that interleukin-6 and interferon-gamma levels were increased in the two experimental, small intestinal submucosa-treated groups at 3 days and 2 weeks postoperatively. The results of mechanical testing demonstrated that the average tensile strength of the repaired abdominal wall in the repair model with combined small intestinal submucosa placement and fascial repair was significantly greater than the values for repairs with fascial closure or small intestinal submucosa placement alone. The use of small intestinal submucosa placement in combination with fascial repair can significantly improve the strength of the repaired abdominal wall after transverse rectus abdominis myocutaneous flap harvesting.     

Electromyographic assessment of rectus abdominis muscle function after deep inferior epigastric perforator flap surgery

SUMMARY: The authors evaluated rectus abdominis muscle function after deep inferior epigastric perforator (DIEP) flap elevation. Fifteen consecutive patients who were operated on for breast reconstruction with a free DIEP flap were included in the study. A turn-amplitude electromyographic analysis was used. For each patient, the muscle activity was recorded in the portion of the muscle that was split for the epigastric perforator vessel dissection, and also in the similar portion of the contralateral nondissected muscle. A first electromyographic examination was carried out soon after surgery (mean follow-up, 9 weeks), and a second electromyographic examination was carried out at a later date (mean follow-up, 15 months). The mean activity of the dissected muscles was 50 percent of the activity of the nondissected muscles at the first electromyographic examination and 70 percent at the second electromyographic examination. The authors suggest that the DIEP flap procedure induces a partial denervation of the rectus abdominis muscle in the area of dissection and that reinnervation occurs over time because the entire width of the muscle and sufficient segmental motor innervation are preserved.     

Breast Reconstruction with the free TRAM or DIEP flap: patient selection,choice of flap,and outcome

Recent reports of breast reconstruction with the deep inferior epigastric perforator (DIEP) flap indicate increased fat necrosis and venous congestion as compared with the free transverse rectus abdominis muscle (TRAM) flap. Although the benefits of the DIEP flap regarding the abdominal wall are well documented, its reconstructive advantage remains uncertain. The main objective of this study was to address selection criteria for the free TRAM and DIEP flaps on the basis of patient characteristics and vascular anatomy of the flap that might minimize flap morbidity. A total of 163 free TRAM or DIEP flap breast reconstructions were performed on 135 women between 1997 and 2000. Four levels of muscle sparing related to the rectus abdominis muscle were used. The free TRAM flap was performed on 118 women, of whom 93 were unilateral and 25 were bilateral, totaling 143 flaps. The DIEP flap procedure was performed on 17 women, of whom 14 were unilateral and three were bilateral, totaling 20 flaps. Morbidities related to the 143 free TRAM flaps included return to the operating room for 11 flaps (7.7 percent), total necrosis in five flaps (3.5 percent), mild fat necrosis in 14 flaps (9.8 percent), mild venous congestion in two flaps (1.4 percent), and lower abdominal bulge in eight women (6.8 percent). Partial flap necrosis did not occur. Morbidities related to the 20 DIEP flaps included return to the operating room for three flaps (15 percent), total necrosis in one flap (5 percent), and mild fat necrosis in two flaps (10 percent). Partial flap necrosis, venous congestion, and a lower abdominal bulge were not observed. Selection of the free TRAM or DIEP flap should be made on the basis of patient weight, quantity of abdominal fat, and breast volume requirement, and on the number, caliber, and location of the perforating vessels. Occurrence of venous congestion and total flap loss in the free TRAM and DIEP flaps appears to be independent of the patient age, weight, degree of muscle sparing, and tobacco use. The occurrence of fat necrosis is related to patient weight (p < 0.001) but not related to patient age or preservation of the rectus abdominis muscle. The ability to perform a sit-up is related to patient weight (p < 0.001) and patient age (p < 0.001) but not related to preservation of the muscle or intercostal nerves. The incidence of lower abdominal bulge is reduced after DIEP flap reconstruction (p < 0.001). The DIEP flap can be an excellent option for properly selected women.     

Breast reconstruction with superficial inferior epigastric artery flaps: a prospective comparison with TRAM and DIEP flaps

Breast reconstruction using the lower abdominal free superficial inferior epigastric artery (SIEA) flap has the potential to virtually eliminate abdominal donor-site morbidity because the rectus abdominis fascia and muscle are not incised or excised. However, despite its advantages, the free SIEA flap for breast reconstruction is rarely used. A prospective study was conducted of the reliability and outcomes of the use of SIEA flaps for breast reconstruction compared with transverse rectus abdominis musculocutaneous (TRAM) and deep inferior epigastric perforator (DIEP) flaps. Breast reconstruction with an SIEA flap was attempted in 47 consecutive free autologous tissue breast reconstructions between August of 2001 and November of 2002. The average patient age was 49 years, and the average body mass index was 27 kg/m. The SIEA flap was used in 14 (30 percent) of these breast reconstructions in 12 patients. An SIEA flap was not used in the remaining 33 cases because the SIEA was absent or was deemed too small. The mean superficial inferior epigastric vessel pedicle length was approximately 7 cm. The internal mammary vessels were used as recipients in all SIEA flap cases so that the flap could be positioned sufficiently medially on the chest wall. The average hospital stay was significantly shorter for patients who underwent unilateral breast reconstruction with SIEA flaps than it was for those who underwent reconstruction with TRAM or DIEP flaps. Of the 47 free flaps, one SIEA flap was lost because of arterial thrombosis. Medium-size and large breasts were reconstructed with hemi-lower abdominal SIEA flaps, with aesthetic results similar to those obtained with TRAM and DIEP flaps. The free SIEA flap is an attractive option for autologous tissue breast reconstruction. Harvest of this flap does not injure the anterior rectus fascia or underlying rectus abdominis muscle. This can potentially eliminate abdominal donor-site complications such as bulge and hernia formation, and decrease weakness, discomfort, and hospital stay compared with TRAM and DIEP flaps. The disadvantages of an SIEA flap are a smaller pedicle diameter and shorter pedicle length than TRAM and DIEP flaps and the absence or inadequacy of an arterial pedicle in most patients. Nevertheless, in selected patients, the SIEA flap offers advantages over the TRAM and DIEP flaps for breast reconstruction.     

Double-pedicle transverse rectus abdominis myocutaneous flap for unilateral breast and chest-wall reconstruction

Fifteen patients underwent unilateral breast and chest-wall reconstruction by a double-pedicle transverse rectus abdominis myocutaneous flap technique. Criteria for using both pedicles include (1) exceptionally large soft-tissue requirements, (2) prior abdominal operations compromising the vasculature to portions of the anterior abdominal wall, and (3) certain higher-risk patients with suspected microvascular pathology. Double pedicles allowed the transfer of the skin island as one unit or as two independent hemiellipses of tissue. Follow-up time ranges from 4 to 17 months. Complications included partial tissue loss in two patients, one abdominal flap seroma, and one patient with a hernia.