- Email: [email protected]
Perforasomes of the upper abdomen: An anatomical study
Journal of Plastic, Reconstructive & Aesthetic Surgery (2014) 67, 42e47
Perforasomes of the upper abdomen: An anatomical study* Manfred Schmidt a,b,*, Ines Tinhofer c, Dominik Duscher c, Georg M. Huemer a,b a
Section of Plastic and Reconstructive Surgery, Department of General Surgery, General Hospital Linz, Krankenhausstrasse 9, 4020 Linz, Austria b maz e Microsurgical Training and Research Center, Industriezeile 36/7, 4020 Linz, Austria c Center for Anatomy and Cell Biology, Medical University of Vienna, Waehringer Strasse 13, 1090 Vienna, Austria Received 24 June 2013; accepted 22 August 2013
KEYWORDS Perforator flap; Propeller flap; Superior epigastric artery perforator; Deep inferior epigastric perforator; Reconstruction; Anatomy
Summary Introduction: Pedicled perforator flaps in the trunk such as the DIEAP or the IMAPflap have increasingly been used for reconstructive purposes. However, perforator flaps of the upper abdominal wall derived from the SEA and DIEA have not been widely reported in literature. The aim of this study was to investigate the vascular basis of perforator flaps of the upper abdominal wall based on the epigastric vascular axis and to describe the location and size of the individual flaps. Methods: The superior and deep inferior epigastric artery perforators (SEAPs and DIEAPs) of the supraumbilical abdominal wall of ten fresh anatomical specimens were selectively injected with Methylene blue solution or India ink. The location and size of the labeled skin area was observed. Finally, the arterial perforators were dissected and the length, diameter and the distance of the perforation point to the midline, xiphoid process and umbilicus were recorded. Results: The SEAPs and DIEAPs supplied the ventromedial skin of the lower thoracic and supraumbilical abdominal wall in a sequential order. The mean size of all injected skin areas was 65 31.4 cm2 (10.2 8.8 cm). A mean number of 9.7 4.2 perforators per specimen was i dentified. The me an ex tern al diamete r of the d iss ecte d per f or ators w as 0.82 0.32 mm. The perforator length until arborization averaged 3.44 1.07 cm. Most perforators were located in an area 2e6 cm from the midline and 0e10 cm below the xiphoid process. Discussion: Through selective injection of perforators, a reliable anatomy of SEAP- and DIEAPflaps of the upper abdominal wall could be demonstrated. From a clinical point of view,
* The results of this study were presented at the 50th Meeting of the Austrian Society of Plastic, Reconstructive and Aesthetic Surgery, October 18e20, 2012 in Linz, Austria and at the 17th IPRAS world congress, February 24eMarch 1, 2013 in Santiago, Chile. * Corresponding author. Section of Plastic & Reconstructive Surgery, Department of General Surgery, General Hospital Linz, Krankenhausstrasse 9, 4020 Linz, Austria. Tel.: þ43 732 7806 73005; fax: þ43 732 7806 3190. E-mail address: [email protected] (M. Schmidt).
1748-6815/$ - see front matter ª 2013 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.bjps.2013.08.017
Upper abdominal wall perforators
43 subcostal SEAP-flaps are of special interest. These flaps may be rotated cranially for lower chest wall or breast reconstruction or deflected caudally for abdominal wall reconstructive purposes. The harvest site can be closed directly or via a reverse abdominoplasty procedure. ª 2013 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.
Introduction Defects of the anterior thoracic and abdominal wall represent a challenging problem in reconstructive surgery.1,2 Pedicled perforator flaps in the trunk have increasingly been used for reconstructive purposes.3 The deep inferior epigastric artery perforator (DIEAP-) flap has become a workhorse for reconstructive surgery especially in free flap breast reconstruction,4 but also as a pedicled flap for defect coverage of the lower trunk and pelvis.5e8 Recently, the internal mammary artery perforator- (IMAP) flap has been reported as an option in covering defects of the ventral neck and thoracic region.9e11 However, perforator flaps derived from the superior epigastric artery (SEA) have not been widely reported in literature. In 1980, Bohmert12 reported on a medially-based thoracoepigastric flap for breast reconstruction, whereas Lejour13 described a pedicled epigastric rectus flap including proximal rectus abdominis muscle and epigastric skin as a technical advancement of the thoracoepigastric flap three years later. In the same year, Boyd14 defined the vascular territories of the superior epigastric and deep inferior epigastric system. Hallock15 was the first to describe a perforator flap based on the superior epigastric artery. Since then a few case series have been published.16e19 To date, only two authors have investigated the vascular basis of the SEAPflap by means of CT-angiography scans.20,21 However, the precise anatomical basis of perforator flaps from the upper abdominal wall supplied by the SEA and supraumbilical DIEA has not been studied in detail. Therefore, the purpose of this study was to determine the vascular basis, location and sizes of skin flaps supplied by the individual perforators of the SEA and supraumbilical DIEA in the upper abdominal wall, and discuss their possible clinical applications.
Material & methods Ten fresh anatomical specimens taken from body donators were dissected bilaterally (six female, four male specimens). Specimens with previous cardiac, thoracic or abdominal surgery were excluded. For the investigation the entire ventral thoracic and abdominal wall was removed en bloc. The SEA was identified at its branching point from the IMA and the DIEA was localized distally. Then, the posterior rectus sheath was opened longitudinally and the rectus abdominis muscle was dissected away from the anterior rectus sheath. Branches perforating the anterior rectus sheath superior to the umbilicus with an external diameter 0.5 mm were carefully preserved and their branching
point from the source vessel identified in a retrograde manner. Subsequently the source vessel was divided proximally and a 22-gauge venous catheter with a 0.9-mm diameter (BD Insyte; Becton Dickinson, S.A., Madrid, Spain) inserted. After clamping of side branches, the perforator was injected selectively with 10 ml of 0.1% Methylene blue solution or India ink. Small leaks were identified and sealed, through either bipolar cautery or small vascular clamps. To visualize overlapping of neighboring perforator territories, alternating injections of methylene blue and India ink were performed. Immediately after injection the specimen was turned around, the labeled skin area was marked by pen and the extent and location of the marked island was recorded. The following parameters of the stained skin area were measured: width and length, distance to the xiphoid process, umbilicus and midline. These parameters were recorded on a datasheet. Representative photographs including a ruler were taken with a digital camera for further morphometric analysis. Then the individual perforators were identified through a midline incision ventrally and followed into the marked area. The length until arborization, external diameter, distance from the midline, xiphoid process and umbilicus to the perforation point and the presence of any accompanying veins were documented. Finally the extent of the labeled skin areas and the angulations of their horizontal axis in relation to a horizontal line perpendicular to the midline were measured using computer aided image analysis software (ImageJ, Version 1.45s, National Institute of Health, USA).
Results The supraumbilical perforators of the SEA and DIEA segmentally supplied the ventromedial skin of the lower thorax and the supra- and periumbilical abdominal wall. The supplied area reached 8 cm above the tip of the xiphoid process to 4 cm below the umbilicus. There was an overlap of supplied skin zones between consecutive perforators. Various injected areas extended over the midline to the contralateral side (see Figures 1 and 2). A total number of 44 perforasomes (on average 4.4 perforasomes per specimen) were successfully injected (range: 1e8). The mean size of all injected skin areas was 65 31.4 cm2 (mean dimension 10.2 8.8 cm). However, skin areas as big as 17 10 cm (Area 130 cm2) were detected (see Table 1). The mean distance of the injected skin areas to the midline averaged 0.5 2.2 cm, but various areas extended up to 3 cm over the midline to the contralateral side (see Table 1). The horizontal long axes of the injected perforasomes were oriented in a moderate laterocaudal direction for
44
M. Schmidt et al. A total number of 97 perforators with a diameter of 0.5 mm or bigger (9.7 4.2 perforators per specimen) were dissected. The mean external diameter of the dissected perforators was 0.82 0.32 mm (range: 0.5e2 mm). The perforator length until arborization averaged 3.44 1.07 cm (range 1.5e7 cm, see Table 2). The vast majority of perforators were located in an area 2e6 cm from the midline and 0e10 cm below the xiphoid process. In particular, the highest frequency of perforators was found 5e5.9 cm from the midline and 0e4.9 cm below the xyphoid in this area (see Table 3). 28 out of the 97 dissected perforators were classified as major (1 mm external diameter21) with 18 out of 20 hemiabdomens exhibiting at least one major perforator. The major perforators were equally distributed along the vertical axis with a tendency of highest concentration in an area 0e4.9 cm below the xiphoid process (8 out of 28 major perforators) (see Table 3). There was no difference in distribution of perforators between left and right hemiabdomens. Every dissected perforator was accompanied by a minimum of one single vein. Two accompanying veins were present in 11% of perforators.
Figure 1 Specimen demonstrating SEA and DIEA perforasomes after selective perforator injection with methylene blue or India ink solution. Note the overlapping of perforasomes.
Figure 2 Female specimen after selective injection of SEA and DIEA-perforators. Note the orientation of subcostal SEAP perforasomes in relation to the costal margin.
subcostal SEAP perforators (mean 9.7 9.6 ) and in a lateral direction for supraumbilical DIEAP perforators (mean 1.1 5.6 ) and in relation to a horizontal line perpendicular to the midline (see Figure 2). Table 1
Discussion The cutaneous blood supply of the anterior trunk is vastly derived from the ventral vascular railroad formed by the internal mammary, superior epigastric and deep inferior epigastric system.14 This vascular system and its branches provide the basis for numerous flaps, which offer a versatile toolbox for the reconstructive surgeon. The deltopectoral flap, the thoracoepigastric flap and the TRAM flap represent early utilization of flaps based on these vessels.22e24 Bohmert12 and Lejour13 both described the use of pedicled epigastric flaps based on branches from the SEA. Concerning perforator flaps of the ventral vascular axis of the trunk only the DIEAP flap has been used widely. The recently described IMAP-flap has been increasingly applied for reconstruction of defects in the ventral neck and thoracic region.9e11 However, perforator flaps derived from the SEAsystem have not been widely reported in literature. Hallock15 was the first to describe a clinical case utilizing a superior epigastric rectus abdominis muscle perforator flap for defect coverage in this region. In addition to clinical case reports,16e19,25 further insight into the anatomic basis of the SEAP-flap was provided by means of computed tomographic angiography studies.20,21 In the present anatomical study, almost 10 perforators with a diameter of 0.5 mm or bigger were found in each specimen. Consequently 4e5 perforators per hemiabdomen can be expected on average in the area between the
Data of injected SEA- and DIEA-perforasomes of the upper abdominal wall.
Perforasomes Range
Total number
Number per specimen
Dimensions [cm]
Area [cm2]
Distance to midline [cm]
44
4.4 1e8
10.2 3.3 8.8 2.2 6.5 5e17 10
65 31.4 19e130
0.5 2.2 5.5 to 3a
Means are given standard deviation. a Minus sign indicating extension of skin area over midline.
Upper abdominal wall perforators
45
Table 2 Data of SEA- and DIEA-perforators of the upper abdominal wall. Total Number External number per diameter specimen [mm] Perforators 97 Range
9.7 4e17
Dissectible lengtha [cm]
0.82 0.32 3.44 1.07 0.5e2 1.5e7
Means are given standard deviation. a Suprafascial course until arborization.
xyphoid process and the umbilicus. Emerging significant perforators >0.5 mm were most frequently encountered in an area 2e6 cm from the midline and 0e10 cm below the xiphoid process (see Table 3). This is in correspondence with Hamdi et al.,20 who found the dominant perforators mainly localized in an area 1.5 and 6.5 cm from the X-axis on both sides and between 3 and 16 cm below the Y-axis. Taking into account that the reference point of their coordinate system was situated more cranially (namely, at the junction between sternal body and the xyphoid bone), both results were even more comparable. The mean external diameter of the perforators in our current study was 0.82 0.32 mm (range 0.5e2 mm) with 29% of dissected perforators being 1 mm of external diameter. This is somewhat smaller in diameter compared to what Hamdi et al.20 and Mah et al.21 found, who studied SEAP anatomy by using multidetector row CT scans. Hamdi judged perforator diameters to be ‘good’ to ‘very good’ in 82.5% of the cases, with a “good” vessel diameter being “around” 1 mm. Mah found a mean of six to seven perforators greater than 0.5 mm per hemiabdomen and over two perforators greater than 1 mm per hemiabdomen. In CT scans, however, vessel diameter is very often overestimated due to the partial volume effect as they state.20 Furthermore, the veins could not be visualized. Due to the observed variability in perforator numbers, location of perforation and external diameter, preoperative Doppler ultrasound or CT-angiography seems mandatory to ensure surgical outcome. In our study, the suprafascial perforator length until arborization averaged 3.4 cm. However, range of flap transposition might be increased by additional transfascial and intramuscular dissection and mobilization of the pedicle. We found, that the mean size of all injected skin areas was 65 31.4 cm2 (10.2 8.8 cm). Skin areas as big as 17 10 cm (Area 130 cm2) were detected. However it has to be taken into account that the flap dimensions may vary considerably in vivo from results after anatomical injection. In vivo, dynamic perforasomes might
Table 3
be even larger (21 12 cm) as demonstrated by Ziegler et al.18 Controversy exists in the current literature concerning preferable SEAP-flap orientation. Distal flap necrosis has been reported especially in vertically designed SEAPflaps.15,17,20 Our findings corroborate that a mediolateral orientation of subcostal SEAP angiosomes yields better outcomes than a craniocaudal direction. This is in agreement with Boyd et al.,14 who studied the vascular territory of the SEA and DIEA in detail in 1983. A transverse band of staining from below the xyphoid process extending laterally across the ribs was seen after injection of the SEA. The SEA connects to the DIEA in a watershed area midway between the xyphoid process and the umbilicus.14 A vertical subcostal SEAP-flap design reaching supraumbilical skin will include neighboring DIEAP angiosomes supplied by at least 2 choke anastomoses, thus predisposing for distal flap vascular compromise. Consequently, a vertical SEAP-flap design extending into the periumbilical region with the nourishing perforator located far proximally in the substernal region might lead to distal flap necrosis. Thus, a vertical flap design might be safer for more caudally located perforators or reduced vertical flap length. A similar situation is found with the skin paddle of the musculocutaneous gracilis flap. Whereas in the initial description of this flap the vertically oriented skin island was prone to tip necrosis, the change to a transverse orientation led to much more safety and a wider field of application.26 Thus, a transversely oriented SEAP-flap based on infraxyphoidal/ subcostally emerging perforators seems of special clinical interest. These flaps may be designed laterally as far as the anterior axillary line and rotated cranially for breast, sternal or chest wall reconstruction15,17e21,25 (see Figure 3). Although a V-Y-advancement of the SEAP-flap has been described,20 a propeller-style movement of the flap tissue appears to have the most advantageous clinical impact. The donor site might be closed directly or via a reversed abdominoplasty procedure. Most often there is a surplus of soft tissue available at the thoracoepigastric junction and the resulting scar lies well concealed in the inframammary fold, especially in female patients. Even if there is the need for a skin graft, it may be excised in a later stage. Recently, Hallock proposed a new algorithm for abdominal wall reconstruction employing mainly pedicled or free perforator flaps.27 These flaps mostly stem from the epigastric inferior and superior vascular axis. Hence, we believe that this anatomical study is important information for the reconstructive surgeon in order to plan and execute pedicled perforator flaps from the upper abdominal region with more safety and confidence. We see a great potential of these flaps in local and regional reconstruction of defects seen in breast surgery, sternal and abdominal wall reconstruction.
Vertical distribution of significant (>0.5 mm) supraumbilical SEA- and DIEA-perforators.
Distance from xiphoid [cm]
5 to 0.1a
0e4.9
5e9.9
10e14.9
15e19.9
Number (%) n Z 97 Major perforators (1 mm, n Z 28)
7 (7.2) 1
34 (35.1) 8
27 (27.8) 6
17 (17.5) 7
12 (12.4) 6
a
Minus sign indicating perforation point cranial to tip of xiphoid.
46
M. Schmidt et al. The upper abdominal wall continues to evolve as a new and exciting donor site for locally and regionally transposed pedicled perforator flaps. In our study, we delineated the pertinent perforator and perforasome anatomy relevant to this region. We are convinced that this information helps in planning these flaps with more safety and confidence. Flaps from this area will definitely become a further milestone as a reconstructive tool in restoration of the breast, sternum and abdomen.
Conflict of interest statement None. No funding was received for this work. The authors have no financial interest in any of the products, devices, or drugs mentioned in this manuscript.
Acknowledgments The authors thank Gernot Autzinger for providing the vivid illustrations.
References
Figure 3 aþb: Artists drawing of a possible clinical application of the inframammary positioned SEAP-flap for defect coverage of the caudal sternal region. Due to the tissue surplus in this region, the donor site can be closed directly in most of the cases. Especially in female patients this donor site is advantageous since the resulting scar might be concealed in the inframammary fold.
1. Matros E, Disa JJ. Uncommon flaps for chest wall reconstruction. Semin Plast Surg 2011;25:55e9. 2. Skoracki RJ, Chang DW. Reconstruction of the chestwall and thorax. J Surg Oncol 2006;94:455e65. 3. Hamdi M, Stillaert FB. Pedicled perforator flaps in the trunk. Clin Plast Surg 2010;37:655e65. 4. Gill PS, Hunt JP, Guerra AB, et al. A 10-year retrospective review of 758 DIEP flaps for breast reconstruction. Plast Reconstr Surg 2004;113:1153e60. 5. Schoeller T, Huemer GM, Otto-Schoeller A, Wechselberger G. Correction of contour deformities of the hip region with a pedicled DIEP flap. Plast Reconstr Surg 2007;119:212e5. 6. Seyhan T, Borman H. Pedicled deep inferior epigastric perforator flap for lower abdominal defects and genital reconstructive surgery. J Reconstr Microsurg 2008;24:405e12. 7. Ang GG, Rozen WM, Chauhan A, Acosta R. The pedicled ‘propeller’ deep inferior epigastric perforator (DIEP) flap for a large abdominal wall defect. J Plast Reconstr Aesthet Surg 2011;64:133e5. 8. Zeng A, Xu J, Yan X, You L, Yang H. Pedicled deep inferior epigastric perforator flap: an alternative method to repair groin and scrotal defects. Ann Plast Surg 2006;57:285e8. 9. Yu P, Roblin P, Chevray P. Internal mammary artery perforator (IMAP) flap for tracheostoma reconstruction. Head Neck 2006; 28:723e9. 10. Vesely MJ, Murray DJ, Novak CB, Gullane PJ, Neligan PC. The internal mammary artery perforator flap: an anatomical study and a case report. Ann Plast Surg 2007;58:156e61. 11. Schmidt M, Aszmann OC, Beck H, Frey M. The anatomic basis of the internal mammary artery perforator flap: a cadaver study. J Plast Reconstr Aesthet Surg 2010;63:191e6. 12. Bohmert H. Experience in breast reconstruction with thoracoepigastric and advancement flaps. Acta Chir Belg 1980;79: 105e10. 13. Lejour M, De MA. Experience with 33 epigastric rectus flaps in breast reconstruction. Handchir Mikrochir Plast Chir 1983;15: 257e60. 14. Boyd JB, Taylor GI, Corlett R. The vascular territories of the superior epigastric and the deep inferior epigastric systems. Plast Reconstr Surg 1984;73:1e16.
Upper abdominal wall perforators 15. Hallock GG. The superior epigastric (RECTUS ABDOMINIS) muscle perforator flap. Ann Plast Surg 2005;55:430e2. 16. Woo KJ, Pyon JK, Lim SY, Mun GH, Bang SI, Oh KS. Deep superior epigastric artery perforator ‘propeller’ flap for abdominal wall reconstruction: a case report. J Plast Reconstr Aesthet Surg 2010;63:1223e6. 17. Uemura T. Superior epigastric artery perforator flap: preliminary report. Plast Reconstr Surg 2007;120:1ee5e. 18. Ziegler K, Schmidt M, Huemer GM. A pedicled superior epigastric artery perforator (SEAP-) propeller flap for 2-cavity reconstruction after oncologic rib resection. Microsurgery 2011;31:335e6. 19. Oni G, Sharma R, Rao R, Unger J, Saint-Cyr M. Bilateral superior epigastric pedicle perforator flaps for total chest wall coverage. J Plast Reconstr Aesthet Surg 2011;64:1104e7. 20. Hamdi M, Van LK, Ulens S, Van HE, Roche N, Monstrey S. Clinical applications of the superior epigastric artery perforator (SEAP) flap: anatomical studies and preoperative perforator mapping with multidetector CT. J Plast Reconstr Aesthet Surg 2009;62: 1127e34. 21. Mah E, Rozen WM, Ashton MW, Flood S. Deep superior epigastric artery perforators: anatomical study and clinical
47
22.
23.
24.
25.
26.
27.
application in sternal reconstruction. Plast Reconstr Surg 2009; 123:1719e23. Bakamjian VY. A two-stage method for pharyngoesophageal reconstruction with a primary pectoral skin flap. Plast Reconstr Surg 1965;36:173e84. Hartrampf CR, Scheflan M, Black PW. Breast reconstruction with a transverse abdominal island flap. Plast Reconstr Surg 1982;69:216e25. Cronin TD, Upton J, McDonough JM. Reconstruction of the breast after mastectomy. Plast Reconstr Surg 1977;59: 1e14. Szychta P, Anderson WD. Islanded pedicled superior epigastric artery perforator flaps for bilateral breast augmentation with mastopexy after massive weight loss. J Plast Reconstr Aesthet Surg 2011;64:1677e81. Schoeller T, Huemer GM, Wechselberger G. The transverse musculocutaneous gracilis flap for breast reconstruction: guidelines for flap and patient selection. Plast Reconstr Surg 2008;122:29e38. Hallock GG. A paradigm shift for soft-tissue coverage of the zones of the abdominal wall using perforator flaps. Plast Reconstr Surg 2012;130:590e9.
Perforasomes of the upper abdomen: An anatomical study* Manfred Schmidt a,b,*, Ines Tinhofer c, Dominik Duscher c, Georg M. Huemer a,b a
Section of Plastic and Reconstructive Surgery, Department of General Surgery, General Hospital Linz, Krankenhausstrasse 9, 4020 Linz, Austria b maz e Microsurgical Training and Research Center, Industriezeile 36/7, 4020 Linz, Austria c Center for Anatomy and Cell Biology, Medical University of Vienna, Waehringer Strasse 13, 1090 Vienna, Austria Received 24 June 2013; accepted 22 August 2013
KEYWORDS Perforator flap; Propeller flap; Superior epigastric artery perforator; Deep inferior epigastric perforator; Reconstruction; Anatomy
Summary Introduction: Pedicled perforator flaps in the trunk such as the DIEAP or the IMAPflap have increasingly been used for reconstructive purposes. However, perforator flaps of the upper abdominal wall derived from the SEA and DIEA have not been widely reported in literature. The aim of this study was to investigate the vascular basis of perforator flaps of the upper abdominal wall based on the epigastric vascular axis and to describe the location and size of the individual flaps. Methods: The superior and deep inferior epigastric artery perforators (SEAPs and DIEAPs) of the supraumbilical abdominal wall of ten fresh anatomical specimens were selectively injected with Methylene blue solution or India ink. The location and size of the labeled skin area was observed. Finally, the arterial perforators were dissected and the length, diameter and the distance of the perforation point to the midline, xiphoid process and umbilicus were recorded. Results: The SEAPs and DIEAPs supplied the ventromedial skin of the lower thoracic and supraumbilical abdominal wall in a sequential order. The mean size of all injected skin areas was 65 31.4 cm2 (10.2 8.8 cm). A mean number of 9.7 4.2 perforators per specimen was i dentified. The me an ex tern al diamete r of the d iss ecte d per f or ators w as 0.82 0.32 mm. The perforator length until arborization averaged 3.44 1.07 cm. Most perforators were located in an area 2e6 cm from the midline and 0e10 cm below the xiphoid process. Discussion: Through selective injection of perforators, a reliable anatomy of SEAP- and DIEAPflaps of the upper abdominal wall could be demonstrated. From a clinical point of view,
* The results of this study were presented at the 50th Meeting of the Austrian Society of Plastic, Reconstructive and Aesthetic Surgery, October 18e20, 2012 in Linz, Austria and at the 17th IPRAS world congress, February 24eMarch 1, 2013 in Santiago, Chile. * Corresponding author. Section of Plastic & Reconstructive Surgery, Department of General Surgery, General Hospital Linz, Krankenhausstrasse 9, 4020 Linz, Austria. Tel.: þ43 732 7806 73005; fax: þ43 732 7806 3190. E-mail address: [email protected] (M. Schmidt).
1748-6815/$ - see front matter ª 2013 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.bjps.2013.08.017
Upper abdominal wall perforators
43 subcostal SEAP-flaps are of special interest. These flaps may be rotated cranially for lower chest wall or breast reconstruction or deflected caudally for abdominal wall reconstructive purposes. The harvest site can be closed directly or via a reverse abdominoplasty procedure. ª 2013 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.
Introduction Defects of the anterior thoracic and abdominal wall represent a challenging problem in reconstructive surgery.1,2 Pedicled perforator flaps in the trunk have increasingly been used for reconstructive purposes.3 The deep inferior epigastric artery perforator (DIEAP-) flap has become a workhorse for reconstructive surgery especially in free flap breast reconstruction,4 but also as a pedicled flap for defect coverage of the lower trunk and pelvis.5e8 Recently, the internal mammary artery perforator- (IMAP) flap has been reported as an option in covering defects of the ventral neck and thoracic region.9e11 However, perforator flaps derived from the superior epigastric artery (SEA) have not been widely reported in literature. In 1980, Bohmert12 reported on a medially-based thoracoepigastric flap for breast reconstruction, whereas Lejour13 described a pedicled epigastric rectus flap including proximal rectus abdominis muscle and epigastric skin as a technical advancement of the thoracoepigastric flap three years later. In the same year, Boyd14 defined the vascular territories of the superior epigastric and deep inferior epigastric system. Hallock15 was the first to describe a perforator flap based on the superior epigastric artery. Since then a few case series have been published.16e19 To date, only two authors have investigated the vascular basis of the SEAPflap by means of CT-angiography scans.20,21 However, the precise anatomical basis of perforator flaps from the upper abdominal wall supplied by the SEA and supraumbilical DIEA has not been studied in detail. Therefore, the purpose of this study was to determine the vascular basis, location and sizes of skin flaps supplied by the individual perforators of the SEA and supraumbilical DIEA in the upper abdominal wall, and discuss their possible clinical applications.
Material & methods Ten fresh anatomical specimens taken from body donators were dissected bilaterally (six female, four male specimens). Specimens with previous cardiac, thoracic or abdominal surgery were excluded. For the investigation the entire ventral thoracic and abdominal wall was removed en bloc. The SEA was identified at its branching point from the IMA and the DIEA was localized distally. Then, the posterior rectus sheath was opened longitudinally and the rectus abdominis muscle was dissected away from the anterior rectus sheath. Branches perforating the anterior rectus sheath superior to the umbilicus with an external diameter 0.5 mm were carefully preserved and their branching
point from the source vessel identified in a retrograde manner. Subsequently the source vessel was divided proximally and a 22-gauge venous catheter with a 0.9-mm diameter (BD Insyte; Becton Dickinson, S.A., Madrid, Spain) inserted. After clamping of side branches, the perforator was injected selectively with 10 ml of 0.1% Methylene blue solution or India ink. Small leaks were identified and sealed, through either bipolar cautery or small vascular clamps. To visualize overlapping of neighboring perforator territories, alternating injections of methylene blue and India ink were performed. Immediately after injection the specimen was turned around, the labeled skin area was marked by pen and the extent and location of the marked island was recorded. The following parameters of the stained skin area were measured: width and length, distance to the xiphoid process, umbilicus and midline. These parameters were recorded on a datasheet. Representative photographs including a ruler were taken with a digital camera for further morphometric analysis. Then the individual perforators were identified through a midline incision ventrally and followed into the marked area. The length until arborization, external diameter, distance from the midline, xiphoid process and umbilicus to the perforation point and the presence of any accompanying veins were documented. Finally the extent of the labeled skin areas and the angulations of their horizontal axis in relation to a horizontal line perpendicular to the midline were measured using computer aided image analysis software (ImageJ, Version 1.45s, National Institute of Health, USA).
Results The supraumbilical perforators of the SEA and DIEA segmentally supplied the ventromedial skin of the lower thorax and the supra- and periumbilical abdominal wall. The supplied area reached 8 cm above the tip of the xiphoid process to 4 cm below the umbilicus. There was an overlap of supplied skin zones between consecutive perforators. Various injected areas extended over the midline to the contralateral side (see Figures 1 and 2). A total number of 44 perforasomes (on average 4.4 perforasomes per specimen) were successfully injected (range: 1e8). The mean size of all injected skin areas was 65 31.4 cm2 (mean dimension 10.2 8.8 cm). However, skin areas as big as 17 10 cm (Area 130 cm2) were detected (see Table 1). The mean distance of the injected skin areas to the midline averaged 0.5 2.2 cm, but various areas extended up to 3 cm over the midline to the contralateral side (see Table 1). The horizontal long axes of the injected perforasomes were oriented in a moderate laterocaudal direction for
44
M. Schmidt et al. A total number of 97 perforators with a diameter of 0.5 mm or bigger (9.7 4.2 perforators per specimen) were dissected. The mean external diameter of the dissected perforators was 0.82 0.32 mm (range: 0.5e2 mm). The perforator length until arborization averaged 3.44 1.07 cm (range 1.5e7 cm, see Table 2). The vast majority of perforators were located in an area 2e6 cm from the midline and 0e10 cm below the xiphoid process. In particular, the highest frequency of perforators was found 5e5.9 cm from the midline and 0e4.9 cm below the xyphoid in this area (see Table 3). 28 out of the 97 dissected perforators were classified as major (1 mm external diameter21) with 18 out of 20 hemiabdomens exhibiting at least one major perforator. The major perforators were equally distributed along the vertical axis with a tendency of highest concentration in an area 0e4.9 cm below the xiphoid process (8 out of 28 major perforators) (see Table 3). There was no difference in distribution of perforators between left and right hemiabdomens. Every dissected perforator was accompanied by a minimum of one single vein. Two accompanying veins were present in 11% of perforators.
Figure 1 Specimen demonstrating SEA and DIEA perforasomes after selective perforator injection with methylene blue or India ink solution. Note the overlapping of perforasomes.
Figure 2 Female specimen after selective injection of SEA and DIEA-perforators. Note the orientation of subcostal SEAP perforasomes in relation to the costal margin.
subcostal SEAP perforators (mean 9.7 9.6 ) and in a lateral direction for supraumbilical DIEAP perforators (mean 1.1 5.6 ) and in relation to a horizontal line perpendicular to the midline (see Figure 2). Table 1
Discussion The cutaneous blood supply of the anterior trunk is vastly derived from the ventral vascular railroad formed by the internal mammary, superior epigastric and deep inferior epigastric system.14 This vascular system and its branches provide the basis for numerous flaps, which offer a versatile toolbox for the reconstructive surgeon. The deltopectoral flap, the thoracoepigastric flap and the TRAM flap represent early utilization of flaps based on these vessels.22e24 Bohmert12 and Lejour13 both described the use of pedicled epigastric flaps based on branches from the SEA. Concerning perforator flaps of the ventral vascular axis of the trunk only the DIEAP flap has been used widely. The recently described IMAP-flap has been increasingly applied for reconstruction of defects in the ventral neck and thoracic region.9e11 However, perforator flaps derived from the SEAsystem have not been widely reported in literature. Hallock15 was the first to describe a clinical case utilizing a superior epigastric rectus abdominis muscle perforator flap for defect coverage in this region. In addition to clinical case reports,16e19,25 further insight into the anatomic basis of the SEAP-flap was provided by means of computed tomographic angiography studies.20,21 In the present anatomical study, almost 10 perforators with a diameter of 0.5 mm or bigger were found in each specimen. Consequently 4e5 perforators per hemiabdomen can be expected on average in the area between the
Data of injected SEA- and DIEA-perforasomes of the upper abdominal wall.
Perforasomes Range
Total number
Number per specimen
Dimensions [cm]
Area [cm2]
Distance to midline [cm]
44
4.4 1e8
10.2 3.3 8.8 2.2 6.5 5e17 10
65 31.4 19e130
0.5 2.2 5.5 to 3a
Means are given standard deviation. a Minus sign indicating extension of skin area over midline.
Upper abdominal wall perforators
45
Table 2 Data of SEA- and DIEA-perforators of the upper abdominal wall. Total Number External number per diameter specimen [mm] Perforators 97 Range
9.7 4e17
Dissectible lengtha [cm]
0.82 0.32 3.44 1.07 0.5e2 1.5e7
Means are given standard deviation. a Suprafascial course until arborization.
xyphoid process and the umbilicus. Emerging significant perforators >0.5 mm were most frequently encountered in an area 2e6 cm from the midline and 0e10 cm below the xiphoid process (see Table 3). This is in correspondence with Hamdi et al.,20 who found the dominant perforators mainly localized in an area 1.5 and 6.5 cm from the X-axis on both sides and between 3 and 16 cm below the Y-axis. Taking into account that the reference point of their coordinate system was situated more cranially (namely, at the junction between sternal body and the xyphoid bone), both results were even more comparable. The mean external diameter of the perforators in our current study was 0.82 0.32 mm (range 0.5e2 mm) with 29% of dissected perforators being 1 mm of external diameter. This is somewhat smaller in diameter compared to what Hamdi et al.20 and Mah et al.21 found, who studied SEAP anatomy by using multidetector row CT scans. Hamdi judged perforator diameters to be ‘good’ to ‘very good’ in 82.5% of the cases, with a “good” vessel diameter being “around” 1 mm. Mah found a mean of six to seven perforators greater than 0.5 mm per hemiabdomen and over two perforators greater than 1 mm per hemiabdomen. In CT scans, however, vessel diameter is very often overestimated due to the partial volume effect as they state.20 Furthermore, the veins could not be visualized. Due to the observed variability in perforator numbers, location of perforation and external diameter, preoperative Doppler ultrasound or CT-angiography seems mandatory to ensure surgical outcome. In our study, the suprafascial perforator length until arborization averaged 3.4 cm. However, range of flap transposition might be increased by additional transfascial and intramuscular dissection and mobilization of the pedicle. We found, that the mean size of all injected skin areas was 65 31.4 cm2 (10.2 8.8 cm). Skin areas as big as 17 10 cm (Area 130 cm2) were detected. However it has to be taken into account that the flap dimensions may vary considerably in vivo from results after anatomical injection. In vivo, dynamic perforasomes might
Table 3
be even larger (21 12 cm) as demonstrated by Ziegler et al.18 Controversy exists in the current literature concerning preferable SEAP-flap orientation. Distal flap necrosis has been reported especially in vertically designed SEAPflaps.15,17,20 Our findings corroborate that a mediolateral orientation of subcostal SEAP angiosomes yields better outcomes than a craniocaudal direction. This is in agreement with Boyd et al.,14 who studied the vascular territory of the SEA and DIEA in detail in 1983. A transverse band of staining from below the xyphoid process extending laterally across the ribs was seen after injection of the SEA. The SEA connects to the DIEA in a watershed area midway between the xyphoid process and the umbilicus.14 A vertical subcostal SEAP-flap design reaching supraumbilical skin will include neighboring DIEAP angiosomes supplied by at least 2 choke anastomoses, thus predisposing for distal flap vascular compromise. Consequently, a vertical SEAP-flap design extending into the periumbilical region with the nourishing perforator located far proximally in the substernal region might lead to distal flap necrosis. Thus, a vertical flap design might be safer for more caudally located perforators or reduced vertical flap length. A similar situation is found with the skin paddle of the musculocutaneous gracilis flap. Whereas in the initial description of this flap the vertically oriented skin island was prone to tip necrosis, the change to a transverse orientation led to much more safety and a wider field of application.26 Thus, a transversely oriented SEAP-flap based on infraxyphoidal/ subcostally emerging perforators seems of special clinical interest. These flaps may be designed laterally as far as the anterior axillary line and rotated cranially for breast, sternal or chest wall reconstruction15,17e21,25 (see Figure 3). Although a V-Y-advancement of the SEAP-flap has been described,20 a propeller-style movement of the flap tissue appears to have the most advantageous clinical impact. The donor site might be closed directly or via a reversed abdominoplasty procedure. Most often there is a surplus of soft tissue available at the thoracoepigastric junction and the resulting scar lies well concealed in the inframammary fold, especially in female patients. Even if there is the need for a skin graft, it may be excised in a later stage. Recently, Hallock proposed a new algorithm for abdominal wall reconstruction employing mainly pedicled or free perforator flaps.27 These flaps mostly stem from the epigastric inferior and superior vascular axis. Hence, we believe that this anatomical study is important information for the reconstructive surgeon in order to plan and execute pedicled perforator flaps from the upper abdominal region with more safety and confidence. We see a great potential of these flaps in local and regional reconstruction of defects seen in breast surgery, sternal and abdominal wall reconstruction.
Vertical distribution of significant (>0.5 mm) supraumbilical SEA- and DIEA-perforators.
Distance from xiphoid [cm]
5 to 0.1a
0e4.9
5e9.9
10e14.9
15e19.9
Number (%) n Z 97 Major perforators (1 mm, n Z 28)
7 (7.2) 1
34 (35.1) 8
27 (27.8) 6
17 (17.5) 7
12 (12.4) 6
a
Minus sign indicating perforation point cranial to tip of xiphoid.
46
M. Schmidt et al. The upper abdominal wall continues to evolve as a new and exciting donor site for locally and regionally transposed pedicled perforator flaps. In our study, we delineated the pertinent perforator and perforasome anatomy relevant to this region. We are convinced that this information helps in planning these flaps with more safety and confidence. Flaps from this area will definitely become a further milestone as a reconstructive tool in restoration of the breast, sternum and abdomen.
Conflict of interest statement None. No funding was received for this work. The authors have no financial interest in any of the products, devices, or drugs mentioned in this manuscript.
Acknowledgments The authors thank Gernot Autzinger for providing the vivid illustrations.
References
Figure 3 aþb: Artists drawing of a possible clinical application of the inframammary positioned SEAP-flap for defect coverage of the caudal sternal region. Due to the tissue surplus in this region, the donor site can be closed directly in most of the cases. Especially in female patients this donor site is advantageous since the resulting scar might be concealed in the inframammary fold.
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