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.     

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.     

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 the DIEP flap or the muscle-sparing (MS-2) free TRAM flap: is there a difference?

The advantages of breast reconstruction using the deep inferior epigastric perforator (DIEP) flap and the muscle-sparing free transverse rectus abdominis musculocutaneous (TRAM) flap (MS-2) are well recognized. Both techniques optimize abdominal function by maintaining the vascularity, innervation, and continuity of the rectus abdominis muscle. The purpose of this study was to compare these two methods of breast reconstruction and determine whether there is a difference in outcome. The study considered 177 women who have had breast reconstruction using muscle-sparing flaps over a 4-year period. This includes 89 women who had an MS-2 free TRAM flap procedure, of which 65 were unilateral and 24 were bilateral, and 88 women who had a DIEP flap procedure, of which 66 were unilateral and 22 were bilateral. The total number of flaps was 223. Mean follow-up was 23 months (range, 3 to 49 months). For all MS-2 free TRAM flaps (n = 113), outcome included fat necrosis in eight (7.1 percent), venous congestion in three (2.7 percent), and total necrosis in two (1.8 percent). For the women who had an MS-2 free TRAM flap, an abdominal bulge occurred in three women (4.6 percent) after unilateral reconstruction and in five women (21 percent) after bilateral reconstruction. The ability to perform sit-ups was noted in 63 women (97 percent) after unilateral reconstruction and 20 women (83 percent) after bilateral reconstruction. For all DIEP flaps (n = 110), outcome included fat necrosis in seven (6.4 percent), venous congestion in five (4.5 percent), and total necrosis in three (2.7 percent) patients. For the women who had DIEP flap reconstruction, an abdominal bulge occurred in one woman (1.5 percent) after unilateral reconstruction and in one woman (4.5 percent) after bilateral reconstruction. The ability to perform sit-ups was noted in all women after unilateral reconstruction and in 21 women (95 percent) after bilateral reconstruction. These results demonstrate that there are no significant differences in fat necrosis, venous congestion, or flap necrosis after DIEP or MS-2 free TRAM flap reconstruction. The percentage of women who are able to perform sit-ups and the percentage of women who did not develop a postoperative abdominal bulge is increased after DIEP flap reconstruction; however, this difference is not statistically significant.     

Fat necrosis in free transverse rectus abdominis myocutaneous and deep inferior epigastric perforator flaps

A series of 310 breasts reconstructed by a single surgeon using free transverse rectus abdominis myocutaneous (TRAM) and deep inferior epigastric perforator (DIEP) flaps was reviewed to see if there were any differences in the incidence of fat necrosis and/or partial flap loss between the two techniques. During the study period, 279 breasts were reconstructed with free TRAM flaps and 31 breasts were reconstructed with DIEP flaps. In the breasts reconstructed with free TRAM flaps, the incidence of partial flap loss was 2.2 percent and the incidence of fat necrosis was 12.9 percent. The DIEP flaps were divided into two groups. For the first eight flaps, patients were selected using the same criteria normally used to choose patients for free TRAM flaps. In this unselected early group, the incidence of partial flap loss was 37.5 percent and the incidence of fat necrosis was 62.5 percent. Because of the high incidence of partial flap loss and fat necrosis in the first eight flaps, subsequent selection was modified to limit the use of DIEP flaps to patients who had at least one sufficiently large perforator in each flap (a palpable pulse and a vein at least 1 mm in diameter) and who did not require more than 70 percent of the flap to create a breast of adequate size. In this later (selected) group, fat necrosis (17.4 percent) and partial flap loss (8.7 percent) were reduced to a level only moderately higher than that found in the free TRAM flap group. From these data, it can be concluded that the incidence of partial flap loss and fat necrosis is higher in DIEP flaps than in free TRAM flaps, probably because the blood flow to the former flap is less robust. This difficulty can be circumvented to some extent, however, by careful patient selection. Factors that should be considered include tobacco use, size of the perforators (especially the vein), and (in unilateral reconstructions) the amount of flap tissue across the midline needed to create an adequately sized breast. If these factors are properly considered when planning the operation, fat necrosis and partial flap loss can be reduced to an acceptable level. For selected patients, the DIEP flap is an excellent technique that can obtain a successful, autologous tissue breast reconstruction with minimal donor-site morbidity. For patients who are not good candidates for reconstruction with this flap, the free TRAM flap remains a good alternative.     

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).     

Comparison of cost for DIEP and free TRAM flap breast reconstructions

A recent article by Kaplan and Allen suggested that deep inferior epigastric perforator (DIEP) flap breast reconstruction was less expensive than reconstruction performed with free transverse rectus abdominis musculocutaneous (TRAM) flaps. To test that hypothesis, a series of patients who had undergone unilateral breast-mound reconstruction by the first author using DIEP or free TRAM flaps between November 1, 1996, and March 30, 2000, were reviewed. Bilateral reconstructions and reconstructions performed by other surgeons in the department were excluded to eliminate all variables except the choice of flap. All hours in the operating room and days in the hospital until discharge were included. Early readmissions for the treatment of complications were included, as were the costs of the mastectomy in the case of immediate reconstructions, but late revisions and nipple reconstructions were not. The totals were then converted into resource costs in 1999 dollars, and the DIEP and free TRAM flap groups compared. There were 21 DIEP flaps and 24 free TRAM flaps in the series. In this series, there was no significant difference between the cost of DIEP and free TRAM flap breast reconstruction.     

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.     

Postoperative morphine requirements of free TRAM and DIEP flaps

In a review of the charts of 158 patients who had undergone breast reconstruction with free transverse rectus abdominis musculocutaneous (TRAM) or deep inferior epigastric perforator (DIEP) flaps and who were treated for postoperative pain with morphine administered by a patient-controlled analgesia pump, the total dose of morphine administered during hospitalization for the flap transfer was measured. Patients whose treatment was supplemented by other intravenous narcotics were excluded from the study. The mean amount of morphine per kilogram required by patients who had reconstruction with DIEP flaps (0.74 mg/kg, n = 26) was found to be significantly less than the amount required by patients who had reconstruction with TRAM flaps (1.65 mg/kg; n = 132; p < 0.001). DIEP flap patients also remained in the hospital less time (mean, 4.73 days) than did free TRAM flap patients (mean, 5.21 days; p = 0.026), but the difference was less than one full hospital day. It was concluded that the use of the DIEP flap does reduce the patient requirement for postoperative pain medication and therefore presumably reduces postoperative pain. It may also slightly shorten hospital stay.     

Comparison of the deep inferior epigastric perforator flap and free transverse rectus abdominis myocutaneous flap in postmastectomy reconstruction: a cost-effectiveness analysis

This study compared the deep inferior epigastric perforator (DIEP) flap and the free transverse rectus abdominis myocutaneous (TRAM) flap in postmastectomy reconstruction using a cost-effectiveness analysis. A decision analytic model was used. Medical costs associated with the two techniques were estimated from the Ontario Ministry of Health Schedule of Benefits for 2002. Hospital costs were obtained from St. Joseph's Healthcare, a university teaching hospital in Hamilton, Ontario, Canada. The utilities of clinically important health states related to breast reconstruction were obtained from 32 "experts" across Canada and converted into quality-adjusted life years. The probabilities of these various clinically important health states being associated with the DIEP and free TRAM flaps were obtained after a thorough review of the literature. The DIEP flap was more costly than the free TRAM flap ($7026.47 versus $6508.29), but it provided more quality-adjusted life years than the free TRAM flap (28.88 years versus 28.53 years). The baseline incremental cost-utility ratio was $1464.30 per quality-adjusted life year, favoring adoption of the DIEP flap. Sensitivity analyses were performed by assuming that the probabilities of occurrence of hernia, abdominal bulging, total flap loss, operating room time, and hospital stay were identical with the DIEP and free TRAM techniques. By assuming that the probability of postoperative hernia for the DIEP flap increased from 0.008 to 0.054 (same as for TRAM flap), the incremental cost-utility ratio changed to $1435.00 per quality-adjusted life year. A sensitivity analysis was performed for the complication of hernia because the DIEP flap allegedly diminishes this complication. Increasing the probability of abdominal bulge from 0.041 to 0.103 for the DIEP flap changed the ratio to $2731.78 per quality-adjusted life year. When the probability of total flap failure was increased from 0.014 to 0.016, the ratio changed to $1384.01 per quality-adjusted life year. When the time in the operating room was assumed to be the same for both flaps, the ratio changed to $4026.57 per quality-adjusted life year. If the hospital stay was assumed to be the same for both flaps, the ratio changed to $1944.30 per quality-adjusted life year. On the basis of the baseline calculation and sensitivity analyses, the DIEP flap remained a cost-effective procedure. Thus, adoption of this new technique for postmastectomy reconstruction is warranted in the Canadian health care system.     

Immediate breast reconstruction: why the free TRAM over the conventional TRAM flap?

Use of the transverse rectus abdominis myocutaneous (TRAM) flap for immediate breast reconstruction is controversial because of fear of flap loss and concern that a high complication rate could interfere with adjuvant therapy. One common complication of the TRAM, partial flap necrosis, can interfere with both institution of postoperative therapy and evaluation for recurrence. In an attempt to minimize this problem, we began using the free TRAM flap based on the inferior deep epigastric vessels. This study compares our experience with conventional superior-pedicled (cTRAM) flaps and free TRAM (fTRAM) flaps. A total of 68 breasts were reconstructed in 63 patients, of which 48 of 68 (71 percent) were conventional TRAM flaps and 20 of 68 (29 percent) were free TRAM flaps. Of the 48 conventional TRAM flaps, 26 (54 percent) were unipedicled and 22 (46 percent) were bipedicled. There were 39 of 48 (81 percent) conventional TRAM flaps and 17 of 20 (85 percent) free TRAM flaps with T1 or T2 lesions. Node-positive patients occurred in 14 of 48 (29 percent) conventional TRAM flaps and 2 of 20 (10 percent) free TRAM flaps. One-fourth of patients in both groups smoked cigarettes. Twenty-one of 48 patients (44 percent) with conventional TRAM flaps required postoperative chemotherapy, and 6 of 21 (29 percent) were delayed because of complications of the TRAM flap. Of the 7 of 20 (35 percent) free TRAM flap patients who required post-operative chemotherapy, only 1 of 7 (14 percent) was delayed because of TRAM flap complications.(ABSTRACT TRUNCATED AT 250 WORDS)     

The deep inferior epigastric perforator flap for breast reconstruction in overweight and obese patients

The authors retrospectively reviewed the computerized records of 71 women undergoing 80 deep inferior epigastric perforator (DIEP) flap reconstructions after mastectomy over a 1-year period. There were 33 normal, 26 overweight, and 12 obese patients. No statistically significant difference in flap complications was found between groups. Overall fat necrosis rates were 11.4 percent for the normal-weight patients, 6.7 percent for the overweight patients, and 6.7 percent for the obese patients. Postoperative hospital time was similar for all groups. The occurrence of abdominal wall fascial laxity was uncommon and similar for all groups. Large (>900 g) reconstructions were completed without prohibitive complications in the reconstruction flap. The DIEP flap represents a significant advance in autologous breast tissue reconstruction. Although concerns regarding fat necrosis rates in DIEP flaps have been voiced, the authors did not see an increasing rate of fat necrosis in their overweight and obese patients, and their overall rate of fat necrosis is comparable to rates reported for free transverse rectus abdominis myocutaneous (TRAM) flaps. Also, increasing body mass index did not seem to affect the rate of delayed complications of the abdominal wall, such as abdominal wall hernia or bulging. Although it was not statistically significant, the authors did observe a trend toward increased wound-healing complications with increasing body mass index. Their data also support the claim that the complete sparing of the rectus abdominis muscles afforded by the DIEP flap avoids abdominal wall fascial bulging or defects often seen in obese TRAM reconstruction patients. Because flap and wound complication rates are similar or superior to those of other autologous tissue reconstruction techniques and the occurrence of abdominal wall defects is all but eliminated, the DIEP flap likely represents the preferred autologous breast reconstruction technique for overweight and obese patients.     

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.     

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.     

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 role of the large superficial vein in survival of proximally based versus distally based sural veno-neuro-fasciocutaneous flaps in a rabbit model

A sural veno-neuro-fasciocutaneous flap in the New Zealand White rabbit was developed, and the role of the large subcutaneous lesser saphenous vein was investigated in proximally based versus distally based flaps. Retrograde dye injection showed that the lesser saphenous vein in rabbits has many valves with strong resistance against reflux. Twenty rabbits were randomly allocated into four groups of 10 flaps each. Group I consisted of proximally based flaps with the lesser saphenous vein intact (outflow) in the veno-neuro-adipofascial pedicle. Group II also consisted of proximally based flaps but the lesser saphenous vein was ligated at 1 cm proximal to the pedicle. Group III consisted of distally based flaps with the lesser saphenous vein intact (inflow) in the veno-neuro-adipofascial pedicle. Group IV also consisted of distally based flaps, but the lesser saphenous vein was ligated at 1 cm distal to the pedicle. The results showed that the mean flap survival area in group I (88.8 percent) was statistically higher than that in group II (62.6 percent, p < 0.001), and was higher in group IV (55.5 percent) than in group III (22.7 percent, p < 0.01). However, group II and group IV had no significant difference (p > 0.05). This experiment demonstrated that flap viability is determined by its intrinsic vascularization, both arterial and venous. The large superficial subcutaneous vein has a positive role (venous outflow) in proximally based flaps but a negative role (venous inflow) in distally based flaps. If the effect of the large subcutaneous vein is excluded, distally based flaps are not inherently inferior to proximally based flaps.     

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.     

Perforator flap breast reconstruction using internal mammary perforator branches as a recipient site: an anatomical and clinical analysis

A variety of useful recipient sites exist for breast reconstruction with free flaps, and correct selection remains a significant decision for the surgeon. Among the main pedicles, the disadvantages of the internal mammary vessels are the necessity of costal cartilage resection and the impairment of future cardiac bypass. This study was designed to reduce morbidity and to seek alternative recipient vessels. In the anatomical part of the study, 32 parasternal regions from 16 fresh cadavers were used. The locations and components of internal mammary perforator branches were measured and a histomorphometric analysis was performed. In the clinical part of the study, 36 patients underwent 38 deep inferior epigastric perforator (DIEP) flap and two superior gluteal artery perforator flap breast reconstructions (31 immediate and four bilateral). The recipient vessels were evaluated. In the anatomical study, there were 22 perforating vessels, with 14 (63.6 percent) on the second intercostal space and 11 (50 percent) with one artery and vein. The average (+/-SD) internal and external perforator artery diameters were 598.48 +/- 176.68 microm and 848.97 +/- 276.68 microm, respectively. In the clinical study, 13 successful anastomoses (32.5 percent) were performed at the internal mammary perforator branches (second and third intercostal spaces) with 12 DIEP flaps and one superior gluteal artery perforator flap (all performed as immediate reconstructions). One case of intraoperative vein thrombosis and one case of pedicle avulsion during flap molding were observed. The anatomic and clinical studies demonstrated that the internal mammary perforator branch as a recipient site is a further refinement to free flap breast reconstruction. However, it is neither a reproducible technique nor potentially applicable in all patients. Preoperative planning between the general surgeon and the plastic surgeon is crucial to preserve the main perforator branches during mastectomy. The procedure was not demonstrable in late reconstructions. The main advantages of internal mammary perforator branches used as recipient sites are sparing of the internal mammary vessels for a possible future cardiac surgery, prevention of thoracic deformities, and reduction of the operative time by limited dissection. Despite this, limited surgical exposure, caliber incompatibility, and technical difficulties have to be considered as the main restrictions.     

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.     

The relative importance of the deep and superficial vascular systems for delay of the transverse rectus abdominis musculocutaneous flap as demonstrated in a rat model

The use of some form of delay maneuver for "high-risk" patients before transfer of the superior pedicled lower transverse rectus abdominis musculocutaneous (TRAM) flap for breast reconstruction has augmented the rate of success in both the experimental and clinical arenas. A common method of vascular delay has been the bilateral division of both the superficial inferior epigastric and deep inferior epigastric vessels. Whether all of these must be divided to adequately effect the delay is unknown. For that matter, the relative importance of the superficial versus the deep vascular systems is unclear. To investigate this uncertainty, a delay was attempted in 61 Sprague-Dawley rats by division of either the superficial inferior epigastric or deep cranial epigastric vessels (the latter is the homologue to the human deep inferior epigastric) in unilateral or bilateral fashion. Division of the contralateral superficial inferior epigastric vessel resulted in significantly greater TRAM flap survival than either ipsilateral or bilateral superficial inferior epigastric vessel division (p = 0.0034 or p = 0.0093, respectively). Division of the ipsilateral or bilateral deep cranial epigastric vessel resulted in significantly greater flap survival than just contralateral deep cranial epigastric vessel division (p = 0.0034 or p = 0.006, respectively). No significant difference was observed between the group having contralateral superficial inferior epigastric or groups with ipsilateral deep cranial epigastric division, implying that either alone would be efficacious to achieve the desired delay effect. This would allow the other vascular system to be retained intact for later potential salvage maneuvers as needed.