Venous interruption is unnecessary to achieve an adequate delay in the rat TRAM flap model

Staged division of any or all inferior dominant pedicles to the human lower transverse rectus abdominis musculocutaneous (TRAM) flap has previously been attempted to invoke the delay phenomenon to enhance the rate of success with the superior-pedicled version, especially for patients at high risk for complications. Regardless of the specific vessels ligated, this has usually been accomplished by division of the source artery and its accompanying vein. Whether division of both vessels is essential remains unclear, however. This issue was investigated by using the authors' standard rat TRAM flap model in 43 female Sprague-Dawley rats, which were randomly assigned to four groups. In group A, both the predominant ipsilateral cranial epigastric artery and the cranial epigastric vein were divided 2 weeks before elevation of the TRAM flap. In group B, only the artery was divided; in group C, only the vein was divided. In an undelayed control group, the TRAM flap was elevated immediately, with no prior pedicle division. The percentages of flap survival in group A (89.3 +/- 7.0 percent) and group B (88.8 +/- 6.5 percent) (both with division of the predominant artery) were significantly greater than that in the control group (64.6 +/- 20.5 percent) (p < 0.001) or that in the group in which the vein alone was divided (73.9 +/- 11.3 percent) (p < 0.01). There was no significant difference between the group that underwent vein division only and the control group (p = 0.102). The clinical implication is that arterial division is critical for TRAM flap delay and that arbitrary venous interruption is unnecessary.     

Augmentation of transmidline skin perfusion and viability in transverse rectus abdominis myocutaneous (TRAM) flaps in the pig.

The aim of this experiment was to design a clinically relevant TRAM flap in the pig and to use this flap model to study the effectiveness of preoperative ligation of the dominant vascular pedicle in augmentation of muscle and skin capillary blood flow and skin viability in the TRAM flap. This TRAM flap model was based on the deep inferior epigastric vascular pedicle, with the center of the transverse skin paddle attached to the underlying rectus abdominis muscle at the superior end of the muscle and extending bilaterally from its attached muscle. The transverse skin paddle (8 x 30 cm) included a contralateral and ipsilateral random portion of skin. This flap model was based on the deep inferior epigastric rather than the superior epigastric vascular pedicle because the deep inferior epigastric vascular pedicle is the smaller of the two in the pig and augmentation of its blood supply by ligation of the dominant superior epigastric vascular pedicle resembles more closely the clinical situation. It was observed that ligation of the dominant superior epigastric vascular pedicle 14 days prior to raising the TRAM flap significantly (p less than 0.05; n = 5) increased the total muscle and skin capillary blood flow and skin viability in the transverse skin paddle compared with the sham-operated control (n = 5).(ABSTRACT TRUNCATED AT 250 WORDS)     

Surgical augmentation of skin blood flow and viability in a pig musculocutaneous flap model

A porcine rectus abdominis musculocutaneous (TRAM) flap model was designed and validated in nine pigs. This TRAM flap was based on the deep inferior epigastric (DIE) vessels with an 8 x 18 cm transverse skin paddle at the superior end of the rectus abdominis muscle. The model was subsequently used to test our hypothesis of surgical augmentation of flap viability by vascular territory expansion. Specifically, we observed that ligation of the superior epigastric (SE) vessels at 4, 7, 14, and 28 days (N = 6 to 8) prior to raising the TRAM flaps significantly increased (p less than 0.05) the length and area of the viable skin in the transverse skin paddles of the treatment flaps compared with the contralateral shammanipulated control flaps. This significant increase in skin viability was seen to be accompanied by a significant increase (p less than 0.05) in skin and muscle capillary blood flow in the treatment TRAM flaps compared with the controls (N = 9). The mechanism of vascular territory expansion is unclear. We postulate that hypoxia resulting from the ligation of the superior epigastric vessels prior to the flap surgery may play a role in the triggering of the deep inferior epigastric artery to take over some of the territory previously perfused by the superior epigastric artery. This would then increase the skin and muscle capillary blood flow in the transverse paddle when the TRAM flap was raised on the deep inferior epigastric vascular pedicle.     

Comparison of three different supercharging procedures in a rat skin flap model

A significant clinical problem in reconstructive surgery is partial loss of a pedicled flap. To resolve this problem, various methods of vascular augmentation have been developed; "supercharging" is one of those techniques. A new rat flap model was developed for investigation of the supercharging procedure, and the efficacy of the arterial supercharging method was examined. The purpose of this study was to investigate how an arterial supercharging procedure could generate large flap survival areas with different supercharging positions in rats. On the basis of the vascular anatomical features of rats, a circumferential skin flap from the lower abdomen to the back, measuring 4 x 12 cm, was marked. The flap was divided along the dorsal midline. Forty rats were divided into four experimental groups, as follows: group 1 (control), flaps based only on the deep circumflex iliac artery and vein; group 2, flaps supercharged with the ipsilateral superficial inferior epigastric artery; group 3, flaps supercharged with the contralateral superficial inferior epigastric artery; group 4, flaps supercharged with the contralateral deep circumflex iliac artery. On the fourth postoperative day, the flaps were evaluated with measurements of necrosis and survival areas. Microfil (Flow Tech, Inc., Carver, Mass.) was then injected manually throughout the body, and the vascular changes produced by supercharging were angiographically evaluated. Compared with group 1 (control), the flap survival areas were significantly greater in distally supercharged flaps in groups 3 and 4 (mean flap survival, 91.2 +/- 5.2 percent and 90.5 +/- 10.6 percent, respectively; p < 0.001) and in proximally supercharged flaps in group 2 (45.9 +/- 4.1 percent, p < 0.05). Angiographic assessment of the flaps that survived completely revealed marked dilation of the choke veins among the territories and reorientation of dilated veins along the axes of the flaps. This study suggests that distal arterial supercharging (contralateral superficial inferior epigastric artery or contralateral deep circumflex iliac artery) is more effective than proximal arterial supercharging (ipsilateral superficial inferior epigastric artery) in increasing flap survival. Although the rat skin flap may not be analogous to human flaps, distal arterial supercharging might have useful therapeutic potential in increasing flap survival in clinical practice.     

The vascular anatomy of rectus abdominis musculocutaneous flaps based on the deep superior epigastric system

Radiographic studies of the deep superior epigastric artery (DSEA) and its connections within the soft tissues of the abdominal wall were performed in 64 fresh cadavers. The patterns of anastomosis between the deep superior epigastric artery and the deep inferior epigastric artery (DIEA) were noted. Type I (29 percent) revealed a single deep superior epigastric artery and deep inferior epigastric artery, type II (57 percent) revealed a double-branched system of each vessel, and type III (14 percent) revealed a system of three or more major branches. In each case, the two systems were united by choke vessels in the segment of muscle above the umbilicus. The supply to the various transverse and vertical skin flaps from the deep superior epigastric artery was defined as a series of captured anatomic territories bounded by choke vessels. The upper transverse and vertical flaps had the best supply, and the TRAM flap had the most tenuous supply. Midline crossover occurs predominantly in the subdermal plexus and on the surface of the rectus sheath. Modifications of the design of the TRAM flap, the case for a delay procedure, the wisdom of including a strip of anterior rectus sheath, and the risks of splitting the muscle with respect to its nerve supply and vascular patterns are discussed on an anatomic basis.     

Extended transverse rectus abdominis musculocutaneous flap

Blood circulation within the conventional TRAM flap is not generous, and the contralateral random portion of the flap may result in fat or skin necrosis. However, this random portion can be extended safely and used for reconstruction by including the superficial epigastric vessels and the superficial circumflex iliac vessels and by anastomosing either of these to the recipient vessels. We have experienced this extended TRAM flap in two patients without any complications.     

Clinical results of TRAM flap delay by selective embolization of the deep inferior epigastric arteries

Preoperative selective embolization of the deep inferior epigastric arteries constitutes a new technique in TRAM flap delay. Whereas surgical ligation of these vessels has proved to be an effective delay procedure in experimental and clinical settings, it requires an additional operative step under general anesthesia. Despite the introduction of the free TRAM leading to improved flap perfusion, this microsurgical technique is not always available because of the requirements of specialized equipment and staff, longer operating hours, and subsequently higher expenses. The search for a minimally invasive, easy, and inexpensive technique to improve perfusion of the pedicled TRAM flap led us to selective embolization of the deep inferior epigastric arteries by an angiographic procedure. After 4 years of experience with this technique, we now present the first clinical results. Breast reconstruction by a delayed pedicled TRAM flap was performed in 40 patients with a mean age of 48.4 years (range, 31 to 66 years). The mean interval between embolization and surgery was 3.6 months. Postoperative data concerning flap survival and complications were available for all patients. Embolization of the deep inferior epigastric arteries was performed bilaterally in 35 patients (87.5 percent) and unilaterally in 5 patients (12.5 percent). Radiotherapy had been applied in 21 patients (52.5 percent) before surgery. Postoperative flap complications consisted of partial necrosis in three (7.5 percent), fat necrosis in one (2.5 percent), impaired wound healing in five (12.5 percent), and postoperative bleeding in two patients (5 percent). Abdominal wound healing complications occurred in six patients (15 percent), abdominal wall weakness in eight (20 percent), and hernia formation in four (10 percent). Surgical corrections were performed at the breast (TRAM flap) in 22 patients (55 percent) and at the abdomen (donor site) in 9 (22.5 percent). Preoperative selective embolization of the deep inferior epigastric arteries constitutes an alternative delay procedure for the pedicled TRAM flap. It is superior to the conventional procedure without delay, offers several advantages compared with surgical ligation of these vessels, and represents an alternative to the free TRAM flap in selected cases.     

Basic fibroblast growth factor expression following surgical delay of rat transverse rectus abdominis myocutaneous flaps

Partial transverse rectus abdominis myocutaneous (TRAM) flap loss in breast reconstruction can be a devastating complication for both patient and surgeon. Surgical delay of the TRAM flap has been shown to improve flap viability and has been advocated in "high-risk" patients seeking autogenous breast reconstruction. Despite extensive clinical evidence of the effectiveness of surgical delay of TRAM flaps, the mechanisms by which the delay phenomenon occurs remain poorly understood. To examine whether angiogenic growth factors such as basic fibroblast growth factor (bFGF) may play a role in the delay phenomenon, the authors studied the expression of bFGF in rat TRAM flaps subjected to surgical delay. Thirty-five female Sprague-Dawley rats were randomly assigned to one of four TRAM flap groups: no delay (n = 6), 7-day delay (n = 12), 14-day delay (n = 10), or 21-day delay (n = 7). Surgical delay consisted of incising skin around the perimeter of the planned 2.5 x 5.0-cm TRAM flap followed by ablation of both superior epigastric arteries and the left inferior epigastric artery, thus preserving the right inferior epigastric artery (the nondominant blood supply to the rectus abdominis muscle of the rat). TRAM flaps were then elevated after 7, 14, and 21 days of delay by raising zones II, III, and IV off the abdominal wall fascia. Once hemostasis was assured, the flaps were sutured back in place. All flaps were designed with the upper border of the flap 1 cm below the xiphoid tip. Three days after the TRAM procedure, postfluorescein planimetry was used to determine percent area viability of both superficial and deep portions of TRAM flaps. All rats were euthanized and full-thickness TRAM specimens were taken from zones I, II, III, and IV for enzyme-linked immunoabsorbent assay analysis of bFGF levels. Statistical testing was done by t test (percent viability) and two-way analysis of variance (bFGF levels). All delayed flaps had significantly higher bFGF levels when compared with all nondelayed control flaps (p < 0.05). The bFGF levels were not different in the rats that received TRAM flaps 7, 14, or 21 days after delay surgery. There was also no significant difference in bFGF levels among zones I through IV. Control rats had more peripheral zone necrosis compared with all delayed TRAM rats. All delayed flaps had a significantly higher area of flap viability superficially than nondelayed control flaps (p < 0.05). There was no difference in deep flap viability. Surgical delay of rat TRAM flaps is associated with improved flap viability and significantly elevated levels of bFGF over nondelayed TRAM flaps at postoperative day 3 after TRAM surgery. The increases in bFGF noted at this time point suggests that bFGF may play a role in the improved TRAM flap viability observed after delay surgery. Further investigation is needed to evaluate the role bFGF may play in the delay phenomenon.     

Investigation of TRAM flap oxygenation and perfusion by near-infrared reflection spectroscopy and color-coded duplex sonography

Near-infrared reflection spectroscopy, used experimentally for investigation of tissue hemoglobin content and oxygenation in various flaps, was tested in the pedicled transverse rectus abdominis musculocutaneous (TRAM) flap, chosen as a simple clinical model because of its well-known vascular anatomy and clinical relevance. The study intended to answer the following questions: Does the near-infrared reflection spectroscopy system used in this study measure tissue hemoglobin content and oxygenation in the superficial skin layers only, as proposed by the manufacturer? Is near-infrared reflection spectroscopy able to detect differences of tissue hemoglobin content and oxygenation in distinct zones of the TRAM flap skin before, early, and late after surgery? Does tissue hemoglobin content and oxygenation correspond to blood flow in the supplying superior epigastric artery and to clinical signs of TRAM flap perfusion and viability? In 11 patients, tissue hemoglobin content and oxygenation in the lower abdomen/TRAM flap, mastectomy skin flap, and contralateral breast were measured by a new near-infrared reflection spectroscopy system preoperatively, early postoperatively, and late postoperatively. Simultaneously, systolic peak flow in the ipsilateral superior epigastric artery was obtained by color-coded duplex sonography. Routine clinical monitoring was performed throughout the early postoperative period. Tissue hemoglobin content and oxygenation in the lower abdomen, mastectomy skin flap, and contralateral breast were similar before surgery but varied considerably between different patients. There were no significant differences among preoperative, early postoperative, and late postoperative values of tissue hemoglobin content and oxygenation in the mastectomy skin flap and contralateral breast. However, near-infrared reflection spectroscopy measurements of the TRAM flap revealed significant differences between preoperative and early postoperative values of tissue hemoglobin content and oxygenation and among zones I, II, and III early after surgery. Tissue hemoglobin content in the TRAM flap skin increased and oxygenation decreased early after surgery. Near-infrared reflection spectroscopy values corresponded to clinical signs of venous congestion predominantly in zone III. Late postoperative return of hemoglobin content and oxygenation in the TRAM flap toward preoperative values can be attributed to improved venous return by reversed flow across regurgitant valves and development of collateral circulation. Finally, there was a significant increase of systolic peak flow in the ipsilateral superior epigastric artery early after surgery. This could be related to the opening of small-caliber choke arteries between the superior and deep inferior epigastric arteries following ligation of the dominant deep inferior epigastric artery and TRAM flap transfer to the chest. Systolic peak flow returned to preoperative values late after surgery. The near-infrared reflection spectroscopy system used in this study appeared to measure hemoglobin content and oxygenation in the superficial skin layers only. Near-infrared reflection spectroscopy was able to detect differences of tissue hemoglobin content and oxygenation in the TRAM flap between preoperative and postoperative measurements and between distinct zones of the TRAM flap early postoperatively. Postoperative changes in near-infrared reflection spectroscopy values corresponded to clinical observations and blood flow in the superior epigastric artery measured by color-coded duplex sonography. Further experience is needed before near-infrared reflection spectroscopy can be advocated for routine clinical flap monitoring.     

Venous congestion and blood flow in free transverse rectus abdominis myocutaneous and deep inferior epigastric perforator flaps

A series of 240 deep inferior epigastric perforator (DIEP) flaps and 271 free transverse rectus abdominis myocutaneous (TRAM) flaps from two institutions was reviewed to determine the incidence of diffuse venous insufficiency that threatened flap survival and required a microvascular anastomosis to drain the superficial inferior epigastric vein. This problem occurred in five DIEP flaps and did not occur in any of the free TRAM flaps. In each of these cases, the presence of a superficial inferior epigastric vein that was larger than usual was noted. It is therefore suggested that if an unusually large superficial inferior epigastric vein is noted when a DIEP flap is elevated, the vein should be preserved for possible use in flap salvage. Anatomical studies with Microfil injections of the superficial venous system of the DIEP or TRAM flap were also performed in 15 cadaver and 3 abdominoplasty specimens to help determine why venous circulation (and flap survival) in zone IV of the flaps is so variable. Large lateral branches crossing the midline were found in only 18 percent of cases, whereas 45 percent had indirect connections through a deeper network of smaller veins and 36 percent had no demonstrable crossing branches at all. This absence of crossing branches in many patients may explain why survival of the zone IV portion of such flaps is so variable and unpredictable.     

Intraoperative physiologic blood flow studies in the TRAM flap.

An intraoperative study was done to establish the functional and quantitative properties of the blood supply to the TRAM flap through the assessment and manipulation of blood flow through the deep epigastric arterial system. Seventeen patients undergoing unilateral postmastectomy breast reconstruction with lower transverse rectus abdominis myocutaneous (TRAM) flaps were studied. The study is divided into two parts: (1) ultrasonic measurement of blood flow in the deep inferior epigastric artery (DIEA), and (2) direct measurement of blood pressure in the deep epigastric arterial system, after division of the deep inferior epigastric artery. With occlusion of the superior epigastric artery at the level of the upper edge of the skin flap, 71 percent of the patients had a decrease in the blood flow through the deep inferior epigastric artery, with an average decrease of 23 percent. This implies that the area of watershed perfusion in the lower TRAM flap is superior to the umbilicus, and therefore, survival of all lower TRAM flap tissues requires reversal in the normal direction of arterial flow to the flap. The blood pressure in the proximal stump of the deep inferior epigastric arterial system averaged 46 percent of the mean systemic blood pressure. Occlusion of the medial and lateral thirds of the isolated rectus muscle decreased the mean arterial blood pressure in the flap an average of 19 percent in 80 percent of the individuals studied. These data support the technique of harvesting the entire rectus muscle, avoiding muscle-splitting maneuvers that may compromise axial blood flow.     

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.     

Contour abnormalities of the abdomen after breast reconstruction with abdominal flaps: the role of muscle preservation.

The purpose of the present study was to determine whether contour abnormalities of the abdomen after breast reconstruction with abdominal flaps are related to the harvest of the rectus abdominis muscle. Abdominal contour was analyzed in 155 women who had breast reconstruction with abdominal flaps; 108 women had free transverse rectus abdominis muscle (TRAM) flaps, 37 had pedicled TRAM flaps, and 10 had deep inferior epigastric perforator (DIEP) flaps. The reconstruction was unilateral in 110 women and bilateral in 45 women. Three methods of muscle-sparing were used; they are classified as preservation of the lateral muscle, preservation of the medial and lateral muscle, or preservation of the entire muscle. One of these three methods of muscle-sparing was used in 91 women (59 percent) and no muscle-sparing was used in 64 women (41 percent). Postoperative contour abnormalities occurred in 15 woman and included epigastric fullness in five, upper bulge in three, and lower bulge in 10. One woman experienced two abnormalities, one woman experienced three, and no woman developed a hernia. Of these abnormalities, 11 occurred after the free TRAM flap, seven after the pedicled TRAM flap, and none after the DIEP flap. Bilateral reconstruction resulted in 11 abnormalities in nine women, and unilateral reconstruction resulted in seven abnormalities in six women. chi2 analysis of the free and pedicled TRAM flaps demonstrates that muscle-sparing explains the observed differences in upper bulge and upper fullness (p = 0.02), with a trend toward significance for lower bulge (p = 0.06). chi2 analysis of the free TRAM and DIEP flaps does not explain the observed difference in abnormal abdominal contour. Analysis of muscle-sparing and non-muscle-sparing methods demonstrates that the observed difference between the techniques is only explained for a lower bulge after the bilateral free TRAM flap (p = 0.04).     

The delay phenomenon: the story unfolds

Our previous studies have shown that when a flap is delayed, there is dilation of existing vessels within the flap not ingrowth of new vessels. The maximal anatomic effect on the arterial tree occurs at the level of the reduced-caliber "choke" anastomotic vessels that link adjacent vascular territories. To further investigate the sequence of anatomic changes that occurs during the delay phenomenon, a large series of 200 rabbits and 17 dogs underwent a flap delay procedure in either skin or muscle and the tissues were examined at postoperative periods between 1 hour and 1 year by using well-established fluorescein, angiographic, light microscopic, immunohistochemical, and electron microscopic techniques. These data in the rabbit skin consistently demonstrated an initial period of vasoconstriction that resolved within 3 hours postoperatively and was followed by an active and progressive dilation of choke vessels that was most dramatic between 48 and 72 hours. In vivo intravenous fluorescein dye testing revealed an interesting parallel in that there was a temporary barrier to the flow of fluorescein that occurred at the level of the choke vessels immediately after the flap was raised and that this temporary barrier-continued to impede the flow toward the flap tip in rabbits where flaps had been delayed for periods up to 72 hours. Thereafter, there was no obstruction to the flow of fluorescein along the flap. During this early delay period of 3 days, light microscopy revealed a decrease in vessel wall thickness associated with an increase in lumen diameter. Over the next 4 days, the luminal diameter continued to dilate to a lesser extent and the vessel wall thickened. Immunohistochemical analysis showed increased cell division, maximal between 24 and 72 hours, in all layers of the choke vessel wall. During this same postoperative interval, transmission electron microscopy revealed phenotypic changes in smooth muscle cells from contractile to synthetic cells. Hypertrophy of the smooth muscle cells was also observed. The vascular endothelium, which initially showed evidence of denudation, was restored to a healthy intact appearance within the first week after delay. When followed for longer periods, long-term studies of the delayed flap of up to 1 year demonstrated dramatically a permanent dilation of the choke vessel lumen and a thickening of the choke vessel wall. In canine studies, one rectus abdominis muscle was delayed by ligating the deep inferior epigastric artery. The time sequence of choke vessel dilation, studied by sequential angiograms in vivo, was comparable to that of the rabbit skin model. To ascertain the permanence and irreversibility of this dilation, the normal circulation of the delayed rectus abdominis muscle was restored by reanastomosing the deep inferior epigastric artery. Even after a recovery period of up to 3 months, the choke vessels remained dilated and tortuous instead of reverting to their original narrow diameters. From this work, it is suggested that the choke vessel dilation seen in the delay period is a permanent and irreversible event. It is an active process associated with both an increase (hyperplasia) and an enlargement (hypertrophy) of the cells in all layers of the choke artery wall and a resultant increase in caliber of these vessels. The time sequence for delay appears to be similar in different species and in different tissues, suggesting the possibility of a universal process for delay.     

The midabdominal TRAM flap for breast reconstruction in morbidly obese patients

The transverse rectus abdominis myocutaneous (TRAM) flap is ideal for postmastectomy reconstruction but is tenuous in morbidly obese patients. Because of their relatively high incidence of postoperative complications, morbidly obese patients are often not considered candidates for autogenous reconstruction. The midabdominal TRAM flap has a more favorable anatomy and may represent an alternative technique in this patient population. The records of 18 morbidly obese patients who underwent postmastectomy reconstruction using a mid-abdominal TRAM flap from 1998 through 2002 were retrospectively reviewed. The mid-abdominal TRAM flap territory includes more of the supraumbilical region than the traditional TRAM flap, corresponding to an area with more abundant musculocutaneous perforators and greater dependence on the superior epigastric vascular system. All patients underwent unipedicled mid-abdominal TRAM flap surgery. Four patients with previous subumbilical midline incisions had a delay procedure with ligation of the inferior epigastric vessels. Complications investigated were flap necrosis greater than 10 percent or sufficient to require surgical revision, abdominal donor-site breakdown, seroma formation, umbilical necrosis, abdominal wall bulging or hernia, deep vein thrombosis, infected mesh, surgical revisions, fat necrosis, and extended hospital stay. At a mean follow-up time of 15.6 months (range, 12 to 24 months), three patients had postoperative complications requiring surgical revision. Two of these patients had previous midline abdominal incisions. One patient had both partial flap necrosis and a donor-site complication. The second patient had partial flap necrosis, and the third had an abdominal donor-site complication. No occurrences of abdominal wall hernia, total flap loss, deep vein thrombosis, infected mesh, extensive surgical revision, or extended hospitalization were noted in this series. The mid-abdominal TRAM flap represents an alternative method for postmastectomy breast reconstruction in morbidly obese patients. Autologous reconstruction using a midabdominal TRAM flap may be considered in this patient population; however, additional research is required to conclusively demonstrate an improved outcome when compared with traditional reconstructive methods.     

The vascular territories of the superior epigastric and the deep inferior epigastric systems

The vascular territories of the superior and the deep inferior epigastric arteries were investigated by dye injection, dissection, and barium radiographic studies. By these means it was established that the deep inferior epigastric artery was more significant than the superior epigastric artery in supplying the skin of the anterior abdominal wall. Segmental branches of the deep epigastric system pass upward and outward into the neurovascular plane of the lateral abdominal wall, where they anastomose with the terminal branches of the lower six intercostal arteries and the ascending branch of the deep circumflex iliac artery. The anastomoses consist of multiple narrow "choke" vessels. Similar connections are seen between the superior and the deep inferior epigastric arteries within the rectus abdominis muscle well above the level of the umbilicus. Many perforating arteries emerge through the anterior rectus sheath, but the highest concentration of major perforators is in the paraumbilical area. These vessels are terminal branches of the deep inferior epigastric artery. They feed into a subcutaneous vascular network that radiates from the umbilicus like the spokes of a wheel. Once again, choke connections exist with adjacent territories: inferiorly with the superficial inferior epigastric artery, inferolaterally with the superficial circumflex iliac artery, and superiorly with the superficial superior epigastric artery. The dominant connections, however, are superolaterally with the lateral cutaneous branches of the intercostal arteries. For breast reconstruction, it would appear that prior ligation of the deep inferior epigastric artery would be of advantage when elevating the lower abdominal skin on a superiorly based rectus abdominis musculocutaneous flap. The vascularity of this flap would be further increased by positioning some part of the skin paddle over the dense pack of large paraumbilical perforators. Based on these anatomic studies, the relative merits of the superior and deep inferior epigastric arteries with respect to local and distant tissue transfer using various elements of the abdominal wall are discussed in detail.     

The value of preoperative Doppler sonography for planning free perforator flaps

The individual perforating vessels have a high degree of anatomical variation, therefore it is desirable to conduct a careful examination of them before undertaking a perforator flap operation. Because locating the vessels beforehand makes performing the operative procedure much easier, the aim of the present study was to assess the value of using simple acoustic Doppler sonography to plan a perforator flap operation. The vessel examinations were carried out before taking 46 free microvascular flaps from either the lower abdominal wall or the buttock for reconstructive breast surgery. The perforating vessels located were marked, and their position relative to the umbilicus or the most cranial point of the rima ani recorded using a coordinate system. In 40 patients, a perforator flap operation (deep inferior epigastric perforator flap, n = 32; superior gluteal artery perforator flap, n = 8) was actually carried out; in six of these patients, a myocutaneous flap was used because of the insufficient availability of perforating vessels. Before the operation, perforating vessels were marked for each patient, with an average of 7.3 for the deep inferior epigastric perforator flap and 6.5 for the superior gluteal artery perforator flap. Out of 286 vessels marked for later perforator flaps, 162 were identified during the operation. A preoperatively marked vessel was used in 37 of 40 patients. In the remaining patients, a vessel was used that had not been previously marked. The vertical and horizontal distance between the perforating vessels identified during the operation and the preoperative marks averaged 0.8 cm. The results show preoperative Doppler sonography to be useful for locating the position of individual perforating vessels, making it much easier to find them during the operation.     

Comparison of TRAM and DIEP flap physiology in a rat model

Dynamic and physiologic studies objectively comparing the attributes of the transverse rectus abdominis musculocutaneous (TRAM) and deep inferior epigastric perforator (DIEP) flaps would be most practical in an animal model. This has now been accomplished using the ventral abdomen of the Sprague-Dawley rat. A conventional TRAM flap, a multiple perforator DIEP flap, and a solitary perforator DIEP flap were raised in three equal groups of five rats each. Flow studies using laser Doppler flowmetry demonstrated the highest flow in zone I in the TRAM flap group (87.6 +/- 15.4 percent), which was a statistically significant difference from the multiple perforator DIEP flap group (45.4 +/- 13.3 percent) and the solitary perforator DIEP flap group (43.4 +/- 26.4 percent) (p = 0.005). Flow in zone IV was proportionately lower for all groups, with no significant difference noted between TRAM and DIEP flaps (p = 0.736). Although ultimate flap survival was greatest for the TRAM flap group (96.1 +/- 6.7 percent) when compared with the multiple perforator DIEP flap (79.8 +/- 15.2 percent) or the solitary perforator DIEP flap groups (77.1 +/- 23.0 percent), this difference was not statistically significant (p = 0.183). In summary, relative flow to these rat ventral abdomen models was directly proportional to the number of retained musculocutaneous perforators, but a single perforator only could routinely allow near-total survival.     

Sequential vascularized iliac bone graft and a superficial circumflex iliac artery perforator flap with a single source vessel for established mandibular defects

The major problems in dealing with established mandibular loss are severe soft-tissue contracture and a limited number of recipient vessels. The skin portion of the iliac osteocutaneous flap often necrotizes in cases without perforators of the deep circumflex iliac vessel. To overcome these problems, eight patients with established mandibular loss and no skin perforators of the deep circumflex iliac vessel were treated with a sequential vascularized iliac bone graft and a superficial circumflex iliac perforator flap with a single recipient vessel. Regarding the recipient vessels, the ipsilateral cervical vessels were used for four patients, and the contralateral facial and ipsilateral superficial temporal vessels were used for two cases each. The superficial circumflex iliac perforator flaps were 7 to 28 cm in length and 3 to 15 cm in width. The iliac bone grafts ranged from 7 to 13 cm in length, and three cases were repaired with the inner cortex of the iliac bone. There were no serious complications, such as flap necrosis or bone infection and resulting absorption. The advantages of this method are that both pedicles are very close to each other and of suitable diameter for anastomosis. Simultaneous flap elevation and preparation for the recipient site is possible. The skin flap and vascularized bone graft can be obtained from the same donor site. A single source vessel can nourish both the large skin area and bone sequentially. Longer dissection of the superficial circumflex iliac system to the proximal femoral division is unnecessary. A large flap can survive with a short segment of the superficial circumflex iliac system. Only the vascularized inner cortex of the iliac bone needs to be used, and the outer iliac cortex can be preserved, which results in less morbidity at the donor site.     

Choice of recipient vessels in delayed TRAM flap breast reconstruction after radiotherapy

This study compared the use of the internal mammary and thoracodorsal recipient vessels in a uniform group of patients who underwent delayed TRAM flap reconstruction after radiotherapy, focusing on usability rates and outcomes. The authors identified 123 delayed TRAM flap patients who had undergone postmastectomy radiotherapy from a prospective database (1990 to 2001). Recipient vessel unusability rates were calculated on the basis of reports of inspection of a vessel, either by direct intraoperative dissection or by findings from color Doppler examination (internal mammary vessels only). Charts were reviewed for outcomes including flap loss, vascular complications, fat necrosis, and lymphedema; t-test and chi-square analyses were performed to compare outcomes and unusability rates, and multiple regression analysis was performed to determine factors influencing outcome. Of the 123 planned free TRAM flaps, 106 were completed as free flaps and 17 were performed as pedicled flaps because of unusable recipient vessels. Of the free flaps, 45 were anastomosed to the internal mammary vessels, 55 to the thoracodorsal vessels, and six to other vessels. The internal mammary and thoracodorsal groups did not differ significantly in body mass index, abdominal scars, smoking history, time delay between irradiation and TRAM flap reconstruction, or flap ischemia time. Radiation doses to the axilla (thoracodorsal), internal mammary chain, and supraclavicular fossa were similar between the groups. The internal mammary vessels were rejected in 11 (20 percent) of 56 cases, and the thoracodorsal vessels were rejected in 19 (26 percent) of 74 cases (p = 0.42). In cases with unusable internal mammary vessels, 46 percent (n = 5) had inadequate veins, 27 percent (n = 3) had inadequate arteries, and in 27 percent (n = 3) both vessels were inadequate. In the 19 cases with unusable thoracodorsal vessels, 84 percent (n = 16) were excessively scarred, 11 percent (n = 2) had inadequate vessels, and 5 percent (n = 1) were absent. Outcomes were similar regardless of recipient vessels used (internal mammary versus thoracodorsal): total flap loss, 0 percent versus 4 percent (p = 0.20); vascular complications, 6.7 percent versus 11 percent (p = 0.46); arm lymphedema, 4.4 percent versus 9 percent (p = 0.37); partial flap loss, 9 percent versus 6 percent (p = 0.54); and fat necrosis, 18 percent versus 15 percent (p = 0.69). Multivariate analysis revealed a trend for higher complication rates in smokers and with the use of the thoracodorsal vessels as the recipients. Overall, no discernible unusability or outcome differences were detected between the internal mammary and thoracodorsal groups.