Superficial Inferior Epigastric Vessels Research Articles

Assessing the prophylactic use of the superficial inferior epigastric vessels (SIEV) for the super – Drainage of deep inferior epigastric perforator flaps (DIEPS), correlated to patient demographic, anatomical and operative risk factors

Assessing the prophylactic use of the superficial inferior epigastric vessels (SIEV) for the super – Drainage of deep inferior epigastric perforator flaps (DIEPS), correlated to patient demographic, anatomical and operative risk factors

Strategic Approaches to Intraflap Anastomosis: Navigating Conjoined DIEP Flap Reconstruction-A Comprehensive Roadmap.

For patients desiring autologous breast reconstruction without adequate abdominal tissue volume, the deep inferior epigastric perforator (DIEP) flap may be stacked or combined with other flaps for bilateral reconstruction. Various combinations of anastomoses have been described in the literature. We sought to describe a framework for intraflap anastomoses. A retrospective review of 17 patients who underwent conjoined DIEP flaps with intraflap anastomoses with a single surgeon was performed. Patient demographics, comorbidities, operative details, and complications were reviewed. A framework scheme was developed for the type of intraflap anastomosis performed. Between 2016 and 2020, 17 patients underwent conjoined DIEP flaps for unilateral breast reconstruction. Fourteen patients had delayed reconstruction. Eleven patients underwent an intraflap anastomosis in which a medial perforator on the left hemiabdomen flap was anastomosed with a distal lateral row perforator in the right hemiabdomen flap (type A). Four patients underwent an intraflap anastomosis in which a left lateral perforator was anastomosed to a right distal lateral row perforator (type B). Two patients underwent an intraflap anastomosis in which the left superficial inferior epigastric vessel was anastomosed to a right lateral row perforator (type C). Complications included reoperation (11.8%), partial flap loss (5.9%), seroma (23.5%), and hematoma (11.8%). We report a detailed framework for intraflap anastomoses of conjoined DIEP flap reconstruction including superficial inferior epigastric artery/superficial inferior epigastric vessel options. Knowledge of this comprehensive framework will allow surgeons to identify the type of intraflap anastomoses required for the anatomy they encounter and will standardize reporting of surgical technique in the literature.

Genitourinary vascularized composite allotransplantation for gender affirmation in trans men: An anatomical feasibility study

Gender affirmation in trans men requires multiple staged procedures. The final masculinizing step involves phalloplasty or metoidioplasty and further incorporation of penile and testicular prostheses. However, these are functionally suboptimal and associated with high complication rates. Therefore, we sought to investigate the anatomical feasibility of one-stage genitourinary vascularized composite allotransplantation (GUVCA) for such gender-affirming surgeries. Twenty fresh cadaveric dissections were performed to delineate the neurovascular anatomy of the proposed GUVCA. Specifically, in donors (n=14), besides the penis and scrotum, the GUVCA included an inferior bladder patch with the urinary sphincter, prostate, seminal vesicles, as well as a strip of the pubic bone. In trans men recipients, osteotomies of the pubic bone to match that of the donor GUVCA were required. Five cadaveric GUVCA transplants were then performed to simulate one-stage gender affirmation surgery. The GUVCA required (1) vascular anastomoses between the recipient's deep inferior epigastric, external pudendal, and superficial circumflex iliac (or superficial inferior epigastric) vessels to the donor's internal pudendal, external pudendal and genitofemoral vessels respectively; (2) neurosynthesis between the recipient pudendal and dorsal clitoral nerves to the donor pudendal and genitofemoral nerves; and (3) urinary bladder anastomosis at the bladder neck, upstream of the urinary sphincter. Average donor measurements (length (cm), diameter (mm)) were: external pudendal artery (2.5, 2.0) and vein (2.0, 3.5), internal pudendal artery (15.0, 4.0), pudendal (15.0, 3.0) and genitofemoral nerves (8.0, 2.0). We have described the anatomical basis for a one-stage GUVCA in trans masculine genitourinary reconstruction.

Step By Step Free Flap Training Based on Inferior Superficial Epigastric Vessels in Rats

Introduction: Skill, knowledge and experience are essential in the field of microsurgery. The repetitive practice of free flaps on reliable models represents a valuable asset for each young surgeon, simulating the challenges of a free flap, before attempting human complex reconstructions. Microsurgery free-flap training is a demanding challenge, with limited options depending on local and regional programs, therefore we comprised a practice system that would add and reinforce microsurgical skills of each aspiring surgeon. Materials and Methods: Wistar rats, weighing 300-400 grams were used, the epigastric flap presenting the advantage of low morbidity with possibility of primary closure, while the donor cervical site represents a recipient area with one of the lowest chances of post-surgical self-mutilation areas in murine models. Results: The aim of this paper is to present a step-wise approach on a reliable training model, using living Wistar rats specimens. Microsurgery and super-microsurgery techniques are trained by harvesting a fascio-cutaneous free flap and transferring it to the cervical area. The aforementioned flap presents a pedicle based on the superficial inferior epigastric vessels at the emergence from the femoral vessels which will be anastomosed to an anterior cervical created defect to the carotid artery end-to-side and to the external jugular vein end-to-end, the epigastric vein presenting a diameter of 0.7-0.8 mm and the epigastric artery a diameter of 0.5-0.6 mm. They can be harvested with patches or stumps of femoral vessels for microsurgical training as an easier entry-level option, or directly for super-microsurgical training. Conclusion: This flap represents a reliable living training model, which can develop microsurgical skills involving raising, transferring and in-setting free flaps, providing ample and valuable knowledge and practice, simulating the challenges of a real-life either microsurgical or super-microsurgical intervention.

Heterogeneous Maturation of Arterio-Venous Fistulas and Loop-Shaped Venous Interposition Grafts: A Histological and 3D Flow Simulation Comparison.

Vascular graft maturation is associated with blood flow characteristics, such as velocity, pressure, vorticity, and wall shear stress (WSS). Many studies examined these factors separately. We aimed to examine the remodeling of arterio-venous fistulas (AVFs) and loop-shaped venous interposition grafts, together with 3D flow simulation. Thirty male Wistar rats were randomly and equally divided into sham-operated, AVF, and loop-shaped venous graft (Loop) groups, using the femoral and superficial inferior epigastric vessels for anastomoses. Five weeks after surgery, the vessels were removed for histological evaluation, or plastic castings were made and scanned for 3D flow simulation. Remodeling of AVF and looped grafts was complete in 5 weeks. Histology showed heterogeneous morphology depending on the distribution of intraluminal pressure and WSS. In the Loop group, an asymmetrical WSS distribution coincided with the intima hyperplasia spots. The tunica media was enlarged only when both pressure and WSS were high. The 3D flow simulation correlated with the histological findings, identifying “hotspots” for intimal hyperplasia formation, suggesting a predictive value. These observations can be useful for microvascular research and for quality control in microsurgical training.

Engineering of axially vascularized bone tissue using natural coral scaffold and osteogenic bone marrow mesenchymal stem cell sheets

IntroductionBlood supply remains one of the obstacles to large bone tissue engineering. This study aimed to generate vascularized bone tissue by inducing axial vascularization into a construct combining natural coral scaffold and a bone marrow mesenchymal stem cells (BMSCs) sheet. Material and methodsIsolated BMSCs were cultured to form an osteogenic cell sheet using a continuous culture method. Natural coral scaffolds were prepared into customized shape with a cylinder of 20 mm length, 8 mm in outer diameter and 5 mm in inner diameter. Then, the freed superficial inferior epigastric vessel of rabbits was first wrapped with a cell sheet, and then inserted into the central passage of the scaffold, after being wrapped with another cell sheet, the complexes were implanted subcutaneously into a rabbit groin area. In contrast, the sheet-scaffold construct that implanted into groin subcutaneous area of the other side of the same rabbit with the distal end of the blood vessel was ligated, which was considered as control. New bone and vascularization formation were evaluated at 12 weeks postoperatively. ResultsThe volume of new bone formation and amount of capillary infiltration in the vascular circulation group were significantly greater than that in the vascular ligation group, which suggested that insertion of axial vessels could significantly promote angiogenesis and osteogenesis of the tissue-engineered bone. ConclusionsThese findings indicate that inserting an arteriovenous bundle into the constructs of mesenchymal stem cell sheet and coral has great potential for clinical applications to repair large bone defects.

Non-invasive postoperative monitoring of pedicled rat skin flap using laser speckle contrast imaging

This study used non-invasive laser speckle contrast imaging (LSCI) modality to evaluate the blood flow changes in murine flap model and to investigate the clinical feasibility of the LSCI for postoperative monitoring. Ten of 6-8weeks old Spraque-Dawley rats with superficial inferior epigastric vessel based pedicled skin flaps were used in this experiment. The color changes of skin flap were evaluated by naked eyes and the LSCI modality 6, 24, and 48h after surgery. In vessel ligated region of skin flap, skin color began to change to a bluish color immediately postoperatively. At 24h postoperatively, skin necrosis was detectable with the naked eye and total necrosis occurred at 48h postoperatively. Changes in laser speckle signal were consistent with changes observed with the naked eye, and blood flow index also presented significant differences between the ligated and non-ligated region. These correlated laser speckle signal patterns suggest that non-invasive monitoring of perfusion by LSCI is a useful technology that may be used to identify the ischemic skin flap.

Abstract P4-14-11: Prolonged survival of mice bearing HER2 positive breast cancer with a therapeutic cancer vaccine via intra-reconstructed abdominal flap administration

Abstract Background: Previously we reported a porous silicon micro-particle based cancer vaccine, which stimulated robust CD8+ T cell-dependent anti-tumor immunity in mice bearing HER2-positive breast cancer. In this study we evaluated the efficacy of the vaccine via single injection into reconstructed abdominal flap after primary tumor mastectomy. Method: To generate murine model of HER2 positive breast cancer murine, 1 × 105 TUBO/luciferase cells were injectedinto both mammary gland fat pad and left ventricle of each 6-8 weeks old female Balb/c mice. Primary and systemic metastatic tumor growth were monitored with a IVIS-200 imaging system. Four days after tumor inoculation, mammary gland fat pad with primary tumor was resected by mastectomy, and superficial inferior epigastric(SIE) vessels based abdominal flap was used for abdominal reconstruction. During the surgery, mice also received one of the three treatments below: 1) negative control without treatments; 2) single intra-flap vaccination of cancer vaccine; and 3) single injection of cancer vaccine via footpad injection. Therapeutic efficacy were monitored with IVIS system weekly. To analyze immune response, popliteal and inguinal lymph nodes were collected one day and seven days post vaccination, and activation of dendritic cells and T cells was evaluated with a flow cytometry. HER2 specific T cells in splenocytes which highly expressed interferon-gamma (IFNγ) were counted by ELISpot. CD3+ T cell infiltration in brain metastatic nodules were analyzed by immunohistochemical assay. Result: Prolonged survival of mice bearing HER2-positive breast cancer was achieved by both intra-flap and intra-dermal vaccination of cancer vaccine. Mice vaccinated via intra-flap injection extended median survival by 9 days (p=0.025), although not as long as intra-dermal treatment (15 days, p=0.034), comparing to control group. In lymph nodes, activated dendritic cells increased in both two vaccinated groups. Interestingly, intra-flap vaccination induced higher response in inguinal lymph node, which considered as the major draining lymph node of this route. Meanwhile, intra-dermal vaccination raised higher immune response in popliteal lymph node. In ELISpot assay, IFNγ secreted T cells were found abundant in splenocytes from both two vaccination groups. Furthermore, efficient infiltration of T cells inside the brain metastatic nodules was found in intra-dermal injection group, which provided potential protection from distal recurrence after mastectomy. Conclusion: Cancer vaccine administrated via intra-flap injection effectively stimulated systemic immune response, and slowed down tumor progression in murine HER2 positive breast cancer model. Citation Format: Xiaoling Liu, Junhua Mai, Chaoyang Meng, Wei Wei, Haifa Shen. Prolonged survival of mice bearing HER2 positive breast cancer with a therapeutic cancer vaccine via intra-reconstructed abdominal flap administration [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P4-14-11.

Intra-arterial injection of human adipose-derived stem cells improves viability of the random component of axial skin flaps in nude mice

Skin flap necrosis is a common postoperative complication in reconstructive surgery. Recent evidence suggests that subcutaneously injected adipose-derived stem cells (ASCs) increase the viability of random skin flaps. Here, we examined whether intra-arterial human ASC administration could improve random component survival of axial skin flaps in nude mice. Human ASCs isolated from a healthy volunteer by liposuction were injected into nude mice through the right femoral artery at a low (1 × 103 cells), medium (1 × 104 cells), or high (1 × 105 cells) dose. After ASC infusion, right superficial inferior epigastric vessels were ligated to create unipedicled superficial inferior epigastric artery (SIEA) flap with random extension. Flap survival was higher in mice from all three ASC-treated groups, and particularly the medium-dose group was 30% better, than in the control group. Histological examination demonstrated a significantly higher vascular density in the axial skin flap in nude mice treated with the medium ASC dose than in control mice. PKH26-labeled ASCs were identified in skin flaps of ASC-treated mice; some endothelial cells exhibited positive staining for human HLA-A. Compared to the control group, mice in ASC-treated groups had higher vascular endothelial growth factor levels and lower tumor necrosis factor α, interferon γ, and interleukin-6 levels. Intra-arterial human ASC administration increased the survival of axial skin flaps by attenuating inflammatory reactions and enhancing neovascularization. Intra-arterial ASC administration might yield a higher rate of these cells and of engraftment in the skin flaps. This approach may have a therapeutic role in increasing flap survival.

A unidirectional porous beta-tricalcium phosphate promotes angiogenesis in a vascularized pedicle rat model

BackgroundVarious types of artificial bone have been developed as alternatives to autologous bone grafts. In designing artificial bone, a porous structure is essential for the infiltration of blood and cells, which promotes angiogenesis within the bone matrix and ultimately ossification. However, it remains unclear what kind of pore system best promotes ossification. Here, we investigated angiogenesis in three different types of porous β-tricalcium phosphate (β-TCP) in a vascularized pedicle rat model. MethodsThree types of porous β-TCP—β-TCP60 (60% porosity), β-TCP75 (75% porosity), and unidirectional porous β-tricalcium phosphate (UDPTCP; 57% porosity)—were examined. A cylindrical piece of artificial bone was implanted beneath the superficial inferior epigastric (SIE) vessels in the groin of rats and angiogenesis was allowed to occur. Two weeks after surgery, India ink or lectin was systemically injected to detect newly formed blood vessels originating from the SIE vessels. Immunohistochemistry for von Willebrand factor, α-smooth muscle actin, or type IV collagen was performed to clarify the structural features of the newly formed capillaries within the vascularized UDPTCP. ResultsThe vascularity of the UDPTCP was superior to that of β-TCP60 and β-TCP75. The UDPTCP pore structure was completely filled with capillaries at 3 weeks after implantation. Immunohistochemistry showed that the walls of the capillaries contained endothelial cells, pericytes, and basement membrane originating from the SIE vessels, and that the cells proliferated and the basement membrane formed simultaneously as the newly formed capillaries extended through the unidirectional pore structure of the UDPTCP. ConclusionsUDPTCP had greater angiogenic potential than β-TCP60 and β-TCP75 in a vascularized pedicle rat model. Vascularized UDPTCP grafts may be an alternative to vascularized autologous bone grafts.

Adipose mesenchymal stem cell-derived exosomes stimulated by hydrogen peroxide enhanced skin flap recovery in ischemia-reperfusion injury

BackgroundMesenchymal stem cell (MSC)-derived exosomes have been recognized as new candidates for the treatment of ischemic disease or injury and may be an alternative treatment for cell therapy. This aim of the study was to evaluate whether exosomes derived from adipose mesenchymal stem cell (ADSC) can protect the skin flap during ischemia-reperfusion (I/R) injury and induce neovascularization. MethodsTo investigate the effects of exosomes in the I/R injury of flap transplantation in vivo, flaps were subjected to 6 h of ischemia by ligating the left superficial inferior epigastric vessels (SIEA) followed by blood perfusion. Exosomes derived from normal ADSC (ADSC-exos) and exosomes derived from ADSC preconditioned with H2O2 (H2O2-ADSC-exos) were injected into the flaps. Then, the blood perfusion unit (BPU) of the flaps was measured by Laser Doppler Perfusion Imaging (LDPI) and microvessel density was determined by the endothelial with cell marker CD31 with Immunohistochemistry (IHC) staining. Inflammatory cell infiltration of the skin flap and apoptosis were detected by hematoxylin & eosin staining (H&E) and the TdT-mediated biotinylated dUTP nick end-labeling (TUNEL) technique. ResultsIn vivo, exosomes significantly increased flap survival and capillary density compared to I/R on postoperative day 5, and decreased the inflammatory reaction and apoptosis in the skin flap (P < 0.05). Furthermore, H2O2-ADSC-exos had better outcomes compared to normal exosomes (P < 0.05). ADSC-exos could significantly increase human umbilical vein endothelial cell (HUVEC) proliferation (P < 0.05), but no statistic difference was found in exosomes derived from different microenvironments (P > 0.05). HUVEC co-cultured with H2O2-ADSC-exos increased the migration ratio and generated more cord-like structures compared to ADSC-exos and the control group (P < 0.05). ConclusionADSC-exos can enhance skin flap survival, promote neovascularization and alleviate the inflammation reaction and apoptosis in the skin flap after I/R injury. The use of a specific microenvironment for in vitro stem cell culture, such as one containing a low concentration of H2O2, will facilitate the development of customized exosomes for cell-free therapeutic applications in skin flap transplantation.

The rat groin flap model redesigned for evaluating treatment effects on ischemia-reperfusion injury

BackgroundAlthough there is a wide application of the rat extended groin flap (epigastric skin flap) in studying different clinical issues, inconsistency arises between studies because many parameters of the extended groin flap have not been well defined. Materials and methodsThe flap is based on the superficial inferior epigastric vessels, which give into a lateral and a medial branch distally. Herein, three steps were taken to redesign this model: First, the ventral vascular anatomy was visualized through an imaging study to determine the flap borders. Second, different ischemic durations were induced on five groups of Lewis rats (n = 5 in each group) by clamping the femoral artery; group 1 (sham group) received no ischemic insult after elevation and was immediately repositioned, and groups 2, 3, 4, and 5 received 12-, 14-, 16-, and 18-hour ischemia, respectively. Percentage of necrosis area was measured after 5 days. Third, the redesigned groin flap model was tested with the ischemic postconditioning for validation. ResultsThe flap borders were determined such that both branches of the superficial inferior epigastric vessels were always included to ensure blood supply consistency. As the 14-hour ischemia induced the least variation in necrotic area on rats, it was chosen for further studies. In addition, ischemic postconditioning after 14-hr ischemia resulted in significant reduction of necrosis in this model. ConclusionsWe have redesigned the extended groin flap model with better-defined borders and consistent vascular anatomy. The ischemia duration was calibrated with predictable necrosis pattern and the practicality was demonstrated. With this model, precise assessment of treatment efficacies on ischemia-reperfusion injury could be achieved in future studies.

Erratum: Prefabricated Flaps: Identification of Microcirculation Structure and Supercharging Technique Improving Survival Area.

Background Microcirculation is an important factor frequently overlooked when studying the survival of prefabricated flaps. In the current study, we use different prefabrication techniques for characterizing microcirculation within the flap, with the goal of finding an effective way to improve its survival area. Methods An abdominal prefabricated flap rodent model was created using a two-stage operation. All rats were randomly divided into six groups ( n = 10/group): group A, prefabricated femoral vessels; group B, prefabricated femoral artery with a connected superficial inferior epigastric vein (SIEV); group C, connected superficial inferior epigastric artery (SIEA) with a prefabricated femoral vein; group D was similar to group A along with a prefabricated SIEA, and group E was similar to group A along with a prefabricated SIEV; and group F acted as a control group and consisted of an axial flap nourished by superficial inferior epigastric vessels. Flaps were assessed for survival area, blood perfusion area, and capillary density using macroscopic analysis, near-infrared fluorescence imaging (NIFI), and histology. Results The survival area was not significantly different when comparing groups B to C, and D to E. The survival area of groups D and E was larger than that of groups B and C. Groups B through E had a smaller survival area in comparison to group F and a larger survival area than group A. NIFI were consistent with the macroscopic outcomes. The capillary density was not significantly different between groups A to C and groups D to F. Conclusion Both arterial and venous supercharging could potentially improve the survival area of prefabricated flaps.

Pedicled Transfer of the Superficial Inguinal Lymph Node Flap for Lymphedema

Background Vascularized lymph node transfer is performed for select patients with lymphedema who remain refractory to nonsurgical therapies. Typically, this involves a microvascular free tissue transfer of donor lymph nodes to the affected area. We describe our experience with the transfer of a pedicled adipofascial flap containing the superficial inguinal lymph nodes for lower extremity lymphedema or penoscrotal lymphedema. Methods In eight patients, a unilateral pedicled superficial inguinal lymph node flap was harvested. The flap consisted of subscarpal adipofascial tissue between the level of the inguinal ligament and the groin crease. Blood supply was from either the superficial circumflex iliac vessels or the superficial inferior epigastric vessels. In certain patients, concurrent lymphaticovenular anastomosis was attempted as well. Results Four patients underwent pedicled superficial inguinal lymph node flap transfer for lower extremity lymphedema and for the other four patients the indication was penoscrotal lymphedema. Seven of the eight study patients reported improvements in their lymphedema symptoms. Postoperative complications included cellulitis in one patient and hematoma in another patient; neither patient required reoperation. Conclusion The pedicled superficial inguinal lymph node flap is a feasible and safe treatment option for either lower extremity lymphedema or genital lymphedema. This case series provides the basis for additional studies regarding the potential use of this vascularized lymph node flap in select patients.

Prefabricated Flaps: Identification of Microcirculation Structure and Supercharging Technique Improving Survival Area.

Background Microcirculation is an important factor frequently overlooked when studying the survival of prefabricated flaps. In the current study, we use different prefabrication techniques for characterizing microcirculation within the flap, with the goal of finding an effective way to improve its survival area. Methods An abdominal prefabricated flap rodent model was created using a two-stage operation. All rats were randomly divided into six groups (n = 10/group): group A, prefabricated femoral vessels; group B, prefabricated femoral artery with a connected superficial inferior epigastric vein (SIEV); group C, connected superficial inferior epigastric artery (SIEA) with a prefabricated femoral vein; group D was similar to group A along with a prefabricated SIEA, and group E was similar to group A along with a prefabricated SIEV; and group F acted as a control group and consisted of an axial flap nourished by superficial inferior epigastric vessels. Flaps were assessed for survival area, blood perfusion area, and capillary density using macroscopic analysis, near-infrared fluorescence imaging (NIFI), and histology. Results The survival area was not significantly different when comparing groups B to C, and D to E. The survival area of groups D and E was larger than that of groups B and C. Groups B through E had a smaller survival area in comparison to group F and a larger survival area than group A. NIFI were consistent with the macroscopic outcomes. The capillary density was not significantly different between groups A to C and groups D to F. Conclusion Both arterial and venous supercharging could potentially improve the survival area of prefabricated flaps.

Microvascular Anastomosis of Submillimeter Vessels—A Training Model in Rats

The advent of supermicrosurgery, which allows the anastomosis and dissection of small-caliber vessels ranging from 0.5 to 0.8mm in diameter, has led to the development of new reconstructive operations. Lymphaticovenous anastomosis, fingertip replantation and perforator flap surgery all require the supermicrosurgical techniques. In this paper, a rat model is described for the training of anastomosis of submillimeter vessels. Spraque-Dawley rats with the weight of 300 to 500g were used as the training models. The gender, weight and size of the femoral vessels of 20 rats were recorded. The segment of the femoral vessel which was lying on the ventral muscle group of the hind limb and distal to the origin of the superficial inferior epigastric vessels was used for the practice of microvascular anastomosis. In this study, there were 13 male and 7 female rats. The mean weight of the 20 rats was 395.6g. The mean diameters of the femoral artery and femoral vein were 0.54mm and 0.56mm respectively. The consistent size and anatomy of the femoral vessel make it a suitable training model for microvascular anastomosis of submillimeter vessels.

Is It Possible to Increase Flap Viability by Hydrostatic Dilation?: An Experimental Study in the Rat Abdominal Fasciocutaneous Flap Model.

Ergun et al previously demonstrated the efficacy of hydrostatic dilation in a TRAM flap model in an experimental study. We investigated the effect of hydrostatic dilation on a fasciocutaneous flap model. Eighteen female Wistar rats were equally divided into 3 groups, of which 1 served as a control. In the second, the abdominal fasciocutaneous flap surgical delay procedure was performed by division of the left superficial inferior epigastric (SIE) vessels. In the third, hydrostatic dilation was performed on the left SIE artery and vein, with a mean pressure of 300 mm Hg, while elevating the flap on the right-sided SIE pedicle. The groups were compared by microangiography and by the survival ratio of abdominal flaps 7 days after elevation. The mean (SD) flap necrosis rates were as follows: control group, 44.75% (4.31%); delay group, 33.32% (7.11%); and hydrostatic dilation group, 32.51% (5.03%). There was a significant difference between the control group and the other 2 groups (P < 0.05). There was no difference between the delay and hydrostatic dilation groups with respect to surface area necrosis. The microangiographies showed remarkable increased vascularity in the delay and hydrostatic dilation groups. Hydrostatic dilation is a new method of enhancing flap viability that could be used in clinical cases in place of surgical delay once further studies and clinical trials are completed.

Effect of Artificial Nerve Conduit Vascularization on Peripheral Nerve in a Necrotic Bed.

Several types of artificial nerve conduit have been used for bridging peripheral nerve gaps as an alternative to autologous nerves. However, their efficacy in repairing nerve injuries accompanied by surrounding tissue damage remains unclear. We fabricated a novel nerve conduit vascularized by superficial inferior epigastric (SIE) vessels and evaluated whether it could promote axonal regeneration in a necrotic bed. A 15-mm nerve conduit was implanted beneath the SIE vessels in the groin of a rat to supply it with blood vessels 2 weeks before nerve reconstruction. We removed a 13-mm segment of the sciatic nerve and then pressed a heated iron against the dorsal thigh muscle to produce a burn. The defects were immediately repaired with an autograft (n = 10), nerve conduit graft (n = 8), or vascularized nerve conduit graft (n = 8). Recovery of motor function was examined for 18 weeks after surgery. The regenerated nerves were electrophysiologically and histologically evaluated. The vascularity of the nerve conduit implanted beneath the SIE vessels was confirmed histologically 2 weeks after implantation. Between 14 and 18 weeks after surgery, motor function of the vascularized conduit group was significantly better than that of the nonvascularized conduit group. Electrophysiological and histological evaluations revealed that although the improvement did not reach the level of reinnervation achieved by an autograft, the vascularized nerve conduit improved axonal regeneration more than did the conduit alone. Vascularization of artificial nerve conduits accelerated peripheral nerve regeneration, but further research is required to improve the quality of nerve regeneration.

The Use of Vascularized Fascia as Carrier in Cases of Prelaminated Fasciocartilaginous and Osseofascial Flaps.

Background This experimental study investigates the use of vascularized fascia as carrier for prelaminated cartilage and bone flaps. Methods A total of 30 male New Zealand white rabbits were divided into two equal groups (A and B). The fascia surrounding the inguinal fat and superficial inferior epigastric vessels was dissected. In group A, the fascia was wrapped around a template (20 × 40 mm) of cartilage harvested from the rabbit's ear. In group B, the fascia was wrapped around a 15 × 35 mm piece of rib cortical bone. After a maturation period of 4 weeks, group A was subdivided into three groups (A1, A2, and A3). In group A1 (six animals) the animals were sacrificed and the flaps were sent for histological examination, in A2 (six animals) the flaps were rotated 180 degrees and anchored at knee level, and in A3 (two animals) the flaps were transferred as free flaps to the right SIE (superficial inferior epigastric vessels). The animals of subgroups A2 and A3 were sacrificed after another maturation period of 2 weeks and the flaps were sent for histological examination. After a maturation period of 6 weeks, group B was subdivided into three subgroups (B1, B2, and B3) corresponding to the cartilage subgroups. Subgroups B2 and B3 were sacrificed after 2 weeks. Results All flaps of groups A and B demonstrated good viability apart from one specimen of subgroup B2. Angiogenesis was present in all groups. Conclusion Meticulously dissected vascularized fascia can be successfully used for prelamination of complex fasciocartilaginous or osseofascial flaps. The required maturation periods are 4 and 6 weeks, respectively.

Suprascarpal fat pad thickness may predict venous drainage patterns in abdominal wall flaps.

Abdominal wall flaps are routinely used in reconstructive procedures. In some patients inadequate venous drainage from the deep vein may cause fat necrosis or flap failure. Occasionally the superficial inferior epigastric vessels (SIEV) are of sufficient size to allow for microvascular revascularization. This study looked at the ratio of the sub- and suprascarpal fat layers, the number of deep system perforators, and SIEV diameter to determine any correlation of the fat topography and SIEV. 50 abdominal/pelvic CT angiograms (100 hemiabdomens) were examined in women aged 34-70 years for number of perforators, SIEV diameter, and fat pad thickness above and below Scarpa's fascia. Data was analyzed using multivariate model. The average suprascarpal and subscarpal layers were 18.6 ± 11.5 mm and 6.2 ± 7.2 mm thick, respectively. The average SIEV diameter was 2.06 ± 0.81 mm and the average number of perforators was 2.09 ± 1.03 per hemiabdomen. Hemiabdomens with suprascarpal thickness>23 mm had greater SIEV diameter [2.69 mm vs. 1.8 mm (P < 0.0001)] The fat layer thickness did not correlate with the number of perforators. Neither subscarpal fat thickness nor suprascarpal-to-subscarpal fat layer thickness correlated significantly with SIEV caliber or number of perforators in multivariate model. Suprascarpal fat pad thicker than 23 mm had larger SIEVs irrespective of the number of deep system perforators. This may indicate a cohort of patients at risk of venous congestion from poor venous drainage if only the deep system is revascularized. We recommend harvesting the SIEV in patients with suprascarpal fat pad >23 mm to aid in superficial drainage.