- Email: [email protected]
The Extended Abdominal Wall Flap for Transplantation
The Extended Abdominal Wall Flap for Transplantation S.T. Hollenbeck, A. Senghaas, R. Turley, K.V. Ravindra, M.R. Zenn, L.S. Levin, and D. Erdmann ABSTRACT Introduction and aims. Patients with extensive loss of the abdominal wall tissue have few options for restoring the abdominal cavity. Composite tissue allotransplantation has been used for limited abdominal wall reconstruction in the setting of visceral transplantation, yet replacement of the entire abdominal wall has not been described. The purpose of this study was to determine the maximal abdominal skin surface available through an external iliac/femoral cuff– based pedicle. Materials and methods. Five human cadaveric abdominal walls were injected with methylene blue to analyze skin perfusion based on either the deep inferior epigastric artery (DIEA; n ⫽ 5) or a cuff of external iliac/femoral artery (n ⫽ 5) containing the deep circumflex iliac, deep inferior epigastric, and superficial inferior epigastric, and superficial circumflex iliac arteries. Results. Abdominal wall flaps were taken full thickness from the costal margin to the midaxillary line and down to the pubic tubercle and proximal thigh. In all specimens, the deep inferior epigastric, deep circumflex iliac, superficial inferior epigastric, and superficial circumflex iliac arteries were found to originate within a 4-cm cuff of the external iliac/femoral artery. Abdominal wall flaps injected through a unilateral external iliac/ femoral segment had a significantly greater degree of total flap perfusion than those injected through the DIEA alone (76.5% ⫾ 4% vs 57.2% ⫾ 5%; Student t test, P ⬍ .05). Conclusions. Perfusion of a large portion of the abdominal wall is possible using a single-vessel anastomosis through a short segment of the external iliac/femoral system. Perfusion is significantly greater than that based on the DIEA vessel alone. ARGE DEFECTS OF THE ABDOMINAL WALL represent a complex clinical challenge. The majority of these patients can be treated with conventional measures including mesh repairs, skin grafting, components separation, tissue expansion, and rotational and even distant flaps. For some patients, these methods may not be available or will not suffice to correct the given defect. This includes patients with extensive loss of domain or multiple enterocutaneous fistulae and those with inadequate abdominal cavity space to accommodate a needed solid organ transplant. For these patients, when tissue donor sites are not available, there are no options. Recently, transplantation of bony and soft tissues, known as composite tissue allotransplantation (CTA), has become a clinical reality for severe defects of the upper extremity, face, and abdominal wall.1– 6 Yet, the experience in abdominal wall transplantation has remained somewhat limited. Levi et al and Cipriani et al reported their outcomes with
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combined solid organ and abdominal wall transplantation in 11 total cases.2,6 In both of these series, the abdominal wall was perfused by the deep inferior epigastric system and has been used to supplement an existing, yet insufficient abdominal wall. While this approach has been useful to help expand a restricted abdominal cavity, it does not seem adequate for patients with near total loss of domain from retracted or absent abdominal wall musculature. CTA is a unique approach in that it does not produce a donor site
From Duke University, Division of Plastic and Reconstructive (S.T.H, A.S., R.T., K.V.R., M.R.Z, D.E), Surgery, Durham, NC, USA; and Penn Orthopaedics Hospital of the University of Pennsylvania (L.S.L.), Philadelphia, PA, USA. Address correspondence to Scott T. Hollenbeck, MD, Duke University Medical Center, Division of Plastic and Reconstructive Surgery, DUMC3945, Durham, NC 27710. E-mail: scott. [email protected]
© 2011 by Elsevier Inc. All rights reserved. 360 Park Avenue South, New York, NY 10010-1710
0041-1345/–see front matter doi:10.1016/j.transproceed.2011.01.176
Transplantation Proceedings, 43, 1701–1705 (2011)
1701
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defect for the living patient. As such, flap construction based on large-caliber central vessels is possible. In this study, we used well-established flap concepts to design a large abdominal wall transplant with a single reliable vessel pedicle. The deep circumflex iliac artery (DCIA), deep inferior epigastric artery (DIEA), superficial inferior epigastric artery (SIEA), and superficial circumflex iliac artery (SCIA) are all well-described flaps of the abdominal wall whose pedicles arise in close proximity (Fig 1).7–10 We hypothesized that these flaps may be combined by carrying a short segment of the external iliac/femoral vessels to provide a large abdominal wall for transplantation. METHODS Dissection Technique The entire abdominal walls of five fresh adult cadavers (three female and two male) were studied. The tissue harvested was defined by the costal margins superiorly and the mid-axillary line laterally (Fig 2). The inferior border was defined by a line 7 cm inferior and parallel to the inguinal ligament connected in the midline at the level of the pubic tubercle. The dissection was begun at the superior aspect of the flap by transecting the superior portion of the rectus abdominus, external oblique, internal oblique, and transversus muscle layers off the costal margin. The peritoneal cavity was entered and the falciform ligament was divided. This allowed for complete access to the abdominal cavity while maintaining primary perfusion of the abdominal wall flap. The flap was further mobilized along the lateral margins toward the iliac crest. At this point, the iliac crest could theoretically be harvested with the flap; however, this was not done in our dissections. The deep circumflex iliac vessels were elevated with the flap at the level of the iliacus muscle toward the posterior aspect of the external iliac vessels. At this point, the dissection continued below the inguinal ligament at the level of the thigh muscle fascia. The superficial circumflex iliac vessels were elevated with the flap at the level of the sartorious muscle and further dissected toward the femoral vessels. Next the inferior and central aspect of the flap was elevated off the pubic tubercle and inferiorly toward the femoral vessels, with care taken to preserve the superficial inferior epigastric vessels. This was
Fig 1. (Left) A schematic representation of the skin paddles associated with the deep circumflex iliac artery flap (blue), deep inferior epigastric artery flap (red), superficial inferior epigastric artery flap (green), and the superficial circumflex iliac artery flap (yellow). (Right) The skin paddles of the four flaps superimposed on one another and the abdominal wall.
HOLLENBECK, SENGHAAS, TURLEY ET AL ensured by keeping the dissection directly over the pubic tubercle and connecting the lower incisions by making a right angle off the pubis bone down into the medial thigh. The medial thigh incision met with the lower lateral incision well below the takeoff of either superficial vessel system. At this point, the femoral vessels were controlled in the proximal thigh at the level of the profundus femoris vessels. From an intra-abdominal approach, the external iliac vessels were controlled 4 to 5 cm proximal to the inguinal ligament. This location ensured that the deep circumflex iliac and deep inferior epigastric vessels were elevated with the flap. Once this has been completed bilaterally, further intra-abdominal dissection and organ harvest could proceed. Once the flap was ready to be harvested, the external iliac vessels and femoral vessels were divided. This gave a segment of external iliac/femoral artery and vein containing the deep circumflex iliac, deep inferior epigratric, superficial inferior epigastric, and superficial circumflex iliac vessels. The remaining attachments to the pelvic wall and bladder were dissected free. Finally, the round ligament (in females) or spermatic cord (in males) were divided intra- and extra-abdominally to completely release the flap.
Tissue Perfusion and Analysis Perfusion comparison studies were performed within each cadaveric abdominal wall (Fig 3). On one side, the external iliac/femoral cuff was cannulated, and on the contralateral side, the deep inferior epigastric artery was cannulated. For the external iliac/femoral side, the presence and location of the deep circumflex iliac, deep inferior epigastric, superficial inferior epigastric, and superficial circumflex iliac artery was noted. Prior to dye injection, the flaps were flushed with tap water and leaking vessels were ligated. This was followed by complete flap encasement in paraffin wax. The injection studies were performed with methylene blue dye, diluted 1:10 in tap water. Dye (50 mL) was injected with a handheld syringe through a 16-gauge angiocath intra-arterial cannula. Following injection, the dye was allowed to sit in the tissue for 12 hours, after which time the paraffin was removed and the skin surface was examined. Digital images were obtained and analyzed using Adobe Photoshop CS5 (Adobe Systems Inc, San Jose, Calif, USA). For each specimen, the extent of perfusion was considered for each half of the abdominal wall. A ratio of total perfusion was calculated for each half of the abdominal wall as follows: area stained in blue/total
EXTENDED ABDOMWAL WALL FLAP
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Fig 2. (Left) Schematic representation of the extended abdominal wall flap outlined with the deep circumflex iliac artery (blue), deep inferior epigastric artery (red), superficial inferior epigastric artery (green), and superficial circumflex iliac artery (yellow) superimposed. (Right) Cadaver shown with the extended abdominal wall flap outlined. The superior aspect of the flap is defined by the subcostal margins. The lateral aspect of the flap is defined by the midaxillary line, and the inferior aspect of the flap is defined by a line that is 7-cm inferior and parallel to the inguinal ligament. The lower central aspect of the flap is defined by the pubic symphysis. area. Comparisons were made between groups using the Student t test, and P ⬍ .05 was considered a significant difference.
RESULTS
In all dissections, the DCIA, DIEA, SIEA and SCIA were identified on both sides. In all cadavers, the vessels had independent origins and were found within a 4-cm span of the external iliac/femoral cuff specimen (Fig 4). Injection with methylene blue demonstrated a wider distribution through the external iliac/femoral cuff system as compared to the DIEA vessel alone (Fig 5). The mean hemiabdominal area perfused through the external iliac/femoral system was
significantly greater than the mean hemiabdominal area perfused through the DIEA vessel alone (76.5% ⫾ 4% vs 57.2% ⫾ 5%; Student t test, P ⬍ .05, Fig 6). DISCUSSION
Based on these studies, we are encouraged that a larger abdominal wall flap may be devised using the external iliac/femoral cuff. The advantage is that in addition to the DIEA, the DCIA, SIEA, and SCIA may also be included in the flap design. This appears to result in a 34% greater perfusion of the abdominal wall than the DIEA system
Fig 3. (Left) Cadaveric dissection showing the outline of the extended abdominal wall flap from the anterior perspective. (Right) Same cadaveric dissection showing the fully mobilized extended abdominal wall flap from the posterior perspective.
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Fig 4. Cadaveric dissection of the external iliac/femoral segment demonstrating the position of the deep circumflex iliac artery (DCIA), deep inferior epigastric artery (DIEA), superficial inferior epigastric artery (SIEA), and superficial circumflex iliac artery (SCIA). The origin of these four vessels lies within a 4-cm segment of the external iliac/femoral artery.
alone. Clinically, this would be most useful in scenarios where a large portion (50%–75%) of the abdominal wall must be replaced. Additionally, incorporating the DCIA vessel allows for iliac crest harvest, which may be beneficial for osteosynthesis and delivery of a donor bone marrow site. While we did observe an improvement in overall abdominal wall skin perfusion, several questions remain. First regards the finding that perfusion in the upper lateral portion of the abdominal wall was limited in both external iliac/femoral injections and DIEA injection studies. This is consistent with the notion that this area of the abdominal wall skin is perfused mainly by branches from the intercostal vessels.11,12 It would seem that in order to capture the entire abdominal wall, at least one intercostal vessel would need to be reattached to antegrade flow. Furthermore, in this study we did not evaluate muscle perfusion. Based on the branches we have used in the extended abdominal wall flap, we suspect that the external oblique muscle would be the most poorly perfused of the abdominal wall muscula-
Fig 5. (Left) Cadaveric dissection of the extended abdominal wall flap injected with 50 mL of dilute methylene blue through the external iliac/femoral system. The midline is marked with a black line. The area stained with methylene blue is shaded with a yellow line. (Right) Same cadaveric specimen injected with 50 mL of methylene blue through the deep inferior epigastric artery. The midline is marked with a black line. The area stained with methylene blue is shaded with a yellow line.
HOLLENBECK, SENGHAAS, TURLEY ET AL
Fig 6. Bar graph demonstrating the mean perfusion area of five hemiabdomen dissections with either the external iliac/femoral (EI/Fem) segment injection or the deep inferior epigastric artery (DIEA) injection. Mean perfusion is represented as a percentage of the entire hemiabdomen that has stained blue.
ture. This is consistent with the fact that this muscle has blood supply primarily derived from branches of the interoastal vessels.12 So again, we conclude that at least one intercostal vessel would need to be reattached to reliably capture the external oblique muscle. An additional concern that must be considered is the potential advantage of creating a functional abdominal wall over a static reconstruction. This principle has been shown in abdominal wall reconstruction using innervated free flaps.13,14 To achieve this, intercostal neurhorraphy would need to be performed to some degree. It remains to be determined if one, two, three, or more intercostal nerves are needed to establish functional recovery of an abdominal wall transplant. However, this should not be overlooked as we move forward with this technique, especially in light of the fact that tacrolimus (a common immunosuppressive drug) has been shown to improve nerve regeneration.15 Still, ethical questions remain in the field of CTA. At this time, we must balance the risks of lifelong immunosuppression with the potential clinical benefits of tissue transplantation. For abdominal wall defects, there are numerous alternative methods for reconstruction and transplantation
EXTENDED ABDOMWAL WALL FLAP
that would seem appropriate for a very limited number of patients. Until improvements in immunomodulation can be shown in other CTA models, abdominal wall transplantation may only be indicated for those patients already on immunosuppression. This would include those receiving a solid organ transplant, in which the abdominal cavity is insufficient for closure. Moreover, while models exist to study its impact,16 the interactions between a tissue transplant and a solid organ transplant remain to be fully elucidated. Finally, the exit strategy for abdominal wall CTA failure must be considered. At this time, emerging biologic materials are being used to reconstitute the fascial layers of the abdominal wall, yet they require vascularized tissue support for ingrowth and incorporation. Moreover, long-term outcome regarding repair durability with these materials has yet to be determined. In most cases, if all other options have failed, skin grafting directly onto the bowel may be performed as a bailout for abdominal wall CTA failure. REFERENCES 1. Francois C, Breidenbach W, Maldonado C, et al: Hand transplantation: comparisons and observations of the first four clinical cases. Microsurgery 20:360, 2000 2. Levi D, Tzakis A, Kato T, et al: Transplantation of the abdominal wall. The Lancet 361:2173, 2003 3. Lanzetta M, Petruzzo P, Margreiter R, et al: The International Registry on Hand and Composite Tissue Transplantation. Transplantation 79:1210, 2005 4. Devauchelle B, Badet L, Lengelé B, et al: First human face allograft: early report. Lancet 368:203, 2006
1705 5. Dubernard J, Lengelé B, Morelon E, et al: Outcomes 18 months after the first human partial face transplantation. N Engl J Med 357:2451, 2007 6. Cipriani R, Contedini F, Santoli M, et al: Abdominal wall transplantation with microsurgical technique. Am J Transplant 7:1304, 2007 7. Bergeron L, Tang M, Morris S: The anatomical basis of the deep circumflex iliac artery perforator flap with iliac crest. Plast Reconstr Surg 120:252, 2007 8. Ohmori K, Harii K: Free groin flaps: their vascular basis. Br J Plastic Surgery 28:238, 1975 9. Taylor G, Corlett R, Boyd J: The versatile deep inferior epigastric (inferior rectus abdominis) flap. Br J Plastic Surgery 37:330, 1984 10. Reardon C, O’Ceallaigh S, O’Sullivan S: An anatomical study of the superficial inferior epigastric vessels in humans* 1. Br J Plast Surg 57:515, 2004 11. Holmstroem H, Lossing C: Lateral thoracodorsal flap: an intercostal perforator flap for breast reconstruction. Semin Plast Surg 16:43, 2002 12. Fisher J: External oblique fasciocutaneous flap for elbow coverage. Plast Reconstr Surg 75:51, 1985 13. Koshima I, Nanba Y, Tutsui T, et al: Dynamic reconstruction of large abdominal defects using a free rectus femoris musculocutaneous flap with normal motor function. Ann Plast Surg 50:420, 2003 14. Williams J, Carlson G, Howell R, et al: The tensor fasciae latae free flap in abdominal-wall reconstruction. J Reconstr Microsurg 13:83, 1997 15. Grand A, Myckatyn T, Mackinnon S, et al: Axonal regeneration after cold preservation of nerve allografts and immunosuppression with tacrolimus in mice. J Neurosurg 96:924, 2002 16. Yang J, Erdmann D, Chang J, et al: A model of sequential heart and composite tissue allotransplant in rats. Plast Reconstr Surg 126:80, 2010
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combined solid organ and abdominal wall transplantation in 11 total cases.2,6 In both of these series, the abdominal wall was perfused by the deep inferior epigastric system and has been used to supplement an existing, yet insufficient abdominal wall. While this approach has been useful to help expand a restricted abdominal cavity, it does not seem adequate for patients with near total loss of domain from retracted or absent abdominal wall musculature. CTA is a unique approach in that it does not produce a donor site
From Duke University, Division of Plastic and Reconstructive (S.T.H, A.S., R.T., K.V.R., M.R.Z, D.E), Surgery, Durham, NC, USA; and Penn Orthopaedics Hospital of the University of Pennsylvania (L.S.L.), Philadelphia, PA, USA. Address correspondence to Scott T. Hollenbeck, MD, Duke University Medical Center, Division of Plastic and Reconstructive Surgery, DUMC3945, Durham, NC 27710. E-mail: scott. [email protected]
© 2011 by Elsevier Inc. All rights reserved. 360 Park Avenue South, New York, NY 10010-1710
0041-1345/–see front matter doi:10.1016/j.transproceed.2011.01.176
Transplantation Proceedings, 43, 1701–1705 (2011)
1701
1702
defect for the living patient. As such, flap construction based on large-caliber central vessels is possible. In this study, we used well-established flap concepts to design a large abdominal wall transplant with a single reliable vessel pedicle. The deep circumflex iliac artery (DCIA), deep inferior epigastric artery (DIEA), superficial inferior epigastric artery (SIEA), and superficial circumflex iliac artery (SCIA) are all well-described flaps of the abdominal wall whose pedicles arise in close proximity (Fig 1).7–10 We hypothesized that these flaps may be combined by carrying a short segment of the external iliac/femoral vessels to provide a large abdominal wall for transplantation. METHODS Dissection Technique The entire abdominal walls of five fresh adult cadavers (three female and two male) were studied. The tissue harvested was defined by the costal margins superiorly and the mid-axillary line laterally (Fig 2). The inferior border was defined by a line 7 cm inferior and parallel to the inguinal ligament connected in the midline at the level of the pubic tubercle. The dissection was begun at the superior aspect of the flap by transecting the superior portion of the rectus abdominus, external oblique, internal oblique, and transversus muscle layers off the costal margin. The peritoneal cavity was entered and the falciform ligament was divided. This allowed for complete access to the abdominal cavity while maintaining primary perfusion of the abdominal wall flap. The flap was further mobilized along the lateral margins toward the iliac crest. At this point, the iliac crest could theoretically be harvested with the flap; however, this was not done in our dissections. The deep circumflex iliac vessels were elevated with the flap at the level of the iliacus muscle toward the posterior aspect of the external iliac vessels. At this point, the dissection continued below the inguinal ligament at the level of the thigh muscle fascia. The superficial circumflex iliac vessels were elevated with the flap at the level of the sartorious muscle and further dissected toward the femoral vessels. Next the inferior and central aspect of the flap was elevated off the pubic tubercle and inferiorly toward the femoral vessels, with care taken to preserve the superficial inferior epigastric vessels. This was
Fig 1. (Left) A schematic representation of the skin paddles associated with the deep circumflex iliac artery flap (blue), deep inferior epigastric artery flap (red), superficial inferior epigastric artery flap (green), and the superficial circumflex iliac artery flap (yellow). (Right) The skin paddles of the four flaps superimposed on one another and the abdominal wall.
HOLLENBECK, SENGHAAS, TURLEY ET AL ensured by keeping the dissection directly over the pubic tubercle and connecting the lower incisions by making a right angle off the pubis bone down into the medial thigh. The medial thigh incision met with the lower lateral incision well below the takeoff of either superficial vessel system. At this point, the femoral vessels were controlled in the proximal thigh at the level of the profundus femoris vessels. From an intra-abdominal approach, the external iliac vessels were controlled 4 to 5 cm proximal to the inguinal ligament. This location ensured that the deep circumflex iliac and deep inferior epigastric vessels were elevated with the flap. Once this has been completed bilaterally, further intra-abdominal dissection and organ harvest could proceed. Once the flap was ready to be harvested, the external iliac vessels and femoral vessels were divided. This gave a segment of external iliac/femoral artery and vein containing the deep circumflex iliac, deep inferior epigratric, superficial inferior epigastric, and superficial circumflex iliac vessels. The remaining attachments to the pelvic wall and bladder were dissected free. Finally, the round ligament (in females) or spermatic cord (in males) were divided intra- and extra-abdominally to completely release the flap.
Tissue Perfusion and Analysis Perfusion comparison studies were performed within each cadaveric abdominal wall (Fig 3). On one side, the external iliac/femoral cuff was cannulated, and on the contralateral side, the deep inferior epigastric artery was cannulated. For the external iliac/femoral side, the presence and location of the deep circumflex iliac, deep inferior epigastric, superficial inferior epigastric, and superficial circumflex iliac artery was noted. Prior to dye injection, the flaps were flushed with tap water and leaking vessels were ligated. This was followed by complete flap encasement in paraffin wax. The injection studies were performed with methylene blue dye, diluted 1:10 in tap water. Dye (50 mL) was injected with a handheld syringe through a 16-gauge angiocath intra-arterial cannula. Following injection, the dye was allowed to sit in the tissue for 12 hours, after which time the paraffin was removed and the skin surface was examined. Digital images were obtained and analyzed using Adobe Photoshop CS5 (Adobe Systems Inc, San Jose, Calif, USA). For each specimen, the extent of perfusion was considered for each half of the abdominal wall. A ratio of total perfusion was calculated for each half of the abdominal wall as follows: area stained in blue/total
EXTENDED ABDOMWAL WALL FLAP
1703
Fig 2. (Left) Schematic representation of the extended abdominal wall flap outlined with the deep circumflex iliac artery (blue), deep inferior epigastric artery (red), superficial inferior epigastric artery (green), and superficial circumflex iliac artery (yellow) superimposed. (Right) Cadaver shown with the extended abdominal wall flap outlined. The superior aspect of the flap is defined by the subcostal margins. The lateral aspect of the flap is defined by the midaxillary line, and the inferior aspect of the flap is defined by a line that is 7-cm inferior and parallel to the inguinal ligament. The lower central aspect of the flap is defined by the pubic symphysis. area. Comparisons were made between groups using the Student t test, and P ⬍ .05 was considered a significant difference.
RESULTS
In all dissections, the DCIA, DIEA, SIEA and SCIA were identified on both sides. In all cadavers, the vessels had independent origins and were found within a 4-cm span of the external iliac/femoral cuff specimen (Fig 4). Injection with methylene blue demonstrated a wider distribution through the external iliac/femoral cuff system as compared to the DIEA vessel alone (Fig 5). The mean hemiabdominal area perfused through the external iliac/femoral system was
significantly greater than the mean hemiabdominal area perfused through the DIEA vessel alone (76.5% ⫾ 4% vs 57.2% ⫾ 5%; Student t test, P ⬍ .05, Fig 6). DISCUSSION
Based on these studies, we are encouraged that a larger abdominal wall flap may be devised using the external iliac/femoral cuff. The advantage is that in addition to the DIEA, the DCIA, SIEA, and SCIA may also be included in the flap design. This appears to result in a 34% greater perfusion of the abdominal wall than the DIEA system
Fig 3. (Left) Cadaveric dissection showing the outline of the extended abdominal wall flap from the anterior perspective. (Right) Same cadaveric dissection showing the fully mobilized extended abdominal wall flap from the posterior perspective.
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Fig 4. Cadaveric dissection of the external iliac/femoral segment demonstrating the position of the deep circumflex iliac artery (DCIA), deep inferior epigastric artery (DIEA), superficial inferior epigastric artery (SIEA), and superficial circumflex iliac artery (SCIA). The origin of these four vessels lies within a 4-cm segment of the external iliac/femoral artery.
alone. Clinically, this would be most useful in scenarios where a large portion (50%–75%) of the abdominal wall must be replaced. Additionally, incorporating the DCIA vessel allows for iliac crest harvest, which may be beneficial for osteosynthesis and delivery of a donor bone marrow site. While we did observe an improvement in overall abdominal wall skin perfusion, several questions remain. First regards the finding that perfusion in the upper lateral portion of the abdominal wall was limited in both external iliac/femoral injections and DIEA injection studies. This is consistent with the notion that this area of the abdominal wall skin is perfused mainly by branches from the intercostal vessels.11,12 It would seem that in order to capture the entire abdominal wall, at least one intercostal vessel would need to be reattached to antegrade flow. Furthermore, in this study we did not evaluate muscle perfusion. Based on the branches we have used in the extended abdominal wall flap, we suspect that the external oblique muscle would be the most poorly perfused of the abdominal wall muscula-
Fig 5. (Left) Cadaveric dissection of the extended abdominal wall flap injected with 50 mL of dilute methylene blue through the external iliac/femoral system. The midline is marked with a black line. The area stained with methylene blue is shaded with a yellow line. (Right) Same cadaveric specimen injected with 50 mL of methylene blue through the deep inferior epigastric artery. The midline is marked with a black line. The area stained with methylene blue is shaded with a yellow line.
HOLLENBECK, SENGHAAS, TURLEY ET AL
Fig 6. Bar graph demonstrating the mean perfusion area of five hemiabdomen dissections with either the external iliac/femoral (EI/Fem) segment injection or the deep inferior epigastric artery (DIEA) injection. Mean perfusion is represented as a percentage of the entire hemiabdomen that has stained blue.
ture. This is consistent with the fact that this muscle has blood supply primarily derived from branches of the interoastal vessels.12 So again, we conclude that at least one intercostal vessel would need to be reattached to reliably capture the external oblique muscle. An additional concern that must be considered is the potential advantage of creating a functional abdominal wall over a static reconstruction. This principle has been shown in abdominal wall reconstruction using innervated free flaps.13,14 To achieve this, intercostal neurhorraphy would need to be performed to some degree. It remains to be determined if one, two, three, or more intercostal nerves are needed to establish functional recovery of an abdominal wall transplant. However, this should not be overlooked as we move forward with this technique, especially in light of the fact that tacrolimus (a common immunosuppressive drug) has been shown to improve nerve regeneration.15 Still, ethical questions remain in the field of CTA. At this time, we must balance the risks of lifelong immunosuppression with the potential clinical benefits of tissue transplantation. For abdominal wall defects, there are numerous alternative methods for reconstruction and transplantation
EXTENDED ABDOMWAL WALL FLAP
that would seem appropriate for a very limited number of patients. Until improvements in immunomodulation can be shown in other CTA models, abdominal wall transplantation may only be indicated for those patients already on immunosuppression. This would include those receiving a solid organ transplant, in which the abdominal cavity is insufficient for closure. Moreover, while models exist to study its impact,16 the interactions between a tissue transplant and a solid organ transplant remain to be fully elucidated. Finally, the exit strategy for abdominal wall CTA failure must be considered. At this time, emerging biologic materials are being used to reconstitute the fascial layers of the abdominal wall, yet they require vascularized tissue support for ingrowth and incorporation. Moreover, long-term outcome regarding repair durability with these materials has yet to be determined. In most cases, if all other options have failed, skin grafting directly onto the bowel may be performed as a bailout for abdominal wall CTA failure. REFERENCES 1. Francois C, Breidenbach W, Maldonado C, et al: Hand transplantation: comparisons and observations of the first four clinical cases. Microsurgery 20:360, 2000 2. Levi D, Tzakis A, Kato T, et al: Transplantation of the abdominal wall. The Lancet 361:2173, 2003 3. Lanzetta M, Petruzzo P, Margreiter R, et al: The International Registry on Hand and Composite Tissue Transplantation. Transplantation 79:1210, 2005 4. Devauchelle B, Badet L, Lengelé B, et al: First human face allograft: early report. Lancet 368:203, 2006
1705 5. Dubernard J, Lengelé B, Morelon E, et al: Outcomes 18 months after the first human partial face transplantation. N Engl J Med 357:2451, 2007 6. Cipriani R, Contedini F, Santoli M, et al: Abdominal wall transplantation with microsurgical technique. Am J Transplant 7:1304, 2007 7. Bergeron L, Tang M, Morris S: The anatomical basis of the deep circumflex iliac artery perforator flap with iliac crest. Plast Reconstr Surg 120:252, 2007 8. Ohmori K, Harii K: Free groin flaps: their vascular basis. Br J Plastic Surgery 28:238, 1975 9. Taylor G, Corlett R, Boyd J: The versatile deep inferior epigastric (inferior rectus abdominis) flap. Br J Plastic Surgery 37:330, 1984 10. Reardon C, O’Ceallaigh S, O’Sullivan S: An anatomical study of the superficial inferior epigastric vessels in humans* 1. Br J Plast Surg 57:515, 2004 11. Holmstroem H, Lossing C: Lateral thoracodorsal flap: an intercostal perforator flap for breast reconstruction. Semin Plast Surg 16:43, 2002 12. Fisher J: External oblique fasciocutaneous flap for elbow coverage. Plast Reconstr Surg 75:51, 1985 13. Koshima I, Nanba Y, Tutsui T, et al: Dynamic reconstruction of large abdominal defects using a free rectus femoris musculocutaneous flap with normal motor function. Ann Plast Surg 50:420, 2003 14. Williams J, Carlson G, Howell R, et al: The tensor fasciae latae free flap in abdominal-wall reconstruction. J Reconstr Microsurg 13:83, 1997 15. Grand A, Myckatyn T, Mackinnon S, et al: Axonal regeneration after cold preservation of nerve allografts and immunosuppression with tacrolimus in mice. J Neurosurg 96:924, 2002 16. Yang J, Erdmann D, Chang J, et al: A model of sequential heart and composite tissue allotransplant in rats. Plast Reconstr Surg 126:80, 2010