Long-Term, Prospective, Multicenter Study of Poly-4-Hydroxybutyrate Mesh (Phasix Mesh) for Hernia Repair in Cohort at Risk for Complication: 60-Month Follow-Up.

BACKGROUND: Long-term resorbable mesh represents a promising technology for ventral and incisional hernia repair (VIHR). This study evaluates poly-4-hydroxybutyrate mesh (P4HB; Phasix Mesh) among comorbid patients with CDC class I wounds. STUDY DESIGN: This prospective, multi-institutional study evaluated P4HB VIHR in comorbid patients with CDC class I wounds. Primary outcomes included hernia recurrence and surgical site infection. Secondary outcomes included pain, device-related adverse events, quality of life, reoperation, procedure time, and length of stay. Evaluations were scheduled at 1, 3, 6, 12, 18, 24, 30, 36, and 60 months. A time-to-event analysis (Kaplan-Meier) was performed for primary outcomes; secondary outcomes were reported as descriptive statistics. RESULTS: A total of 121 patients (46 male, 75 female) 54.7 ± 12.0 years old with a BMI of 32.2 ± 4.5 kg/m 2 underwent VIHR with P4HB Mesh (mean ± SD). Fifty-four patients (44.6%) completed the 60-month follow-up. Primary outcomes (Kaplan-Meier estimates at 60 months) included recurrence (22.0 ± 4.5%; 95% CI 11.7% to 29.4%) and surgical site infection (10.1 ± 2.8%; 95% CI 3.3 to 14.0). Secondary outcomes included seroma requiring intervention (n = 9), procedure time (167.9 ± 82.5 minutes), length of stay (5.3 ± 5.3 days), reoperation (18 of 121, 14.9%), visual analogue scale-pain (change from baseline -3.16 ± 3.35 cm at 60 months; n = 52), and Carolinas Comfort Total Score (change from baseline -24.3 ± 21.4 at 60 months; n = 52). CONCLUSIONS: Five-year outcomes after VIHR with P4HB mesh were associated with infrequent complications and durable hernia repair outcomes. This study provides a framework for anticipated long-term hernia repair outcomes when using P4HB mesh.

Prospective, multicenter study of P4HB (Phasix™) mesh for hernia repair in cohort at risk for complications: 3-Year follow-up.

BACKGROUND: This study represents a prospective, multicenter, open-label study to assess the safety, performance, and outcomes of poly-4-hydroxybutyrate (P4HB, Phasix™) mesh for primary ventral, primary incisional, or multiply-recurrent hernia in subjects at risk for complications. This study reports 3-year clinical outcomes. MATERIALS AND METHODS: P4HB mesh was implanted in 121 patients via retrorectus or onlay technique. Physical exam and/or quality of life surveys were completed at 1, 3, 6,12, 18, 24, and 36 months, with 5-year (60-month) follow-up ongoing. RESULTS: A total of n = 121 patients were implanted with P4HB mesh (n = 75 (62%) female) with a mean age of 54.7 ± 12.0 years and mean BMI of 32.2 ± 4.5 kg/m2 (±standard deviation). Comorbidities included: obesity (78.5%), active smokers (23.1%), COPD (28.1%), diabetes mellitus (33.1%), immunosuppression (8.3%), coronary artery disease (21.5%), chronic corticosteroid use (5.0%), hypo-albuminemia (2.5%), advanced age (5.0%), and renal insufficiency (0.8%). Hernias were repaired via retrorectus (n = 45, 37.2% with myofascial release (MR) or n = 43, 35.5% without MR), onlay (n = 8, 6.6% with MR or n = 24, 19.8% without MR), or not reported (n = 1, 0.8%). 82 patients (67.8%) completed 36-month follow-up. 17 patients (17.9% ± 0.4%) experienced hernia recurrence at 3 years, with n = 9 in the retrorectus group and n = 8 in the onlay group. SSI (n = 11) occurred in 9.3% ± 0.03% of patients. CONCLUSIONS: Long-term outcomes following ventral hernia repair with P4HB mesh demonstrate low recurrence rates at 3-year (36-month) postoperative time frame with no patients developing late mesh complications or requiring mesh removal. 5-year (60-month) follow-up is ongoing.

Prospective evaluation of poly-4-hydroxybutyrate mesh in CDC class I/high-risk ventral and incisional hernia repair: 18-month follow-up.

BACKGROUND: Long-term resorbable mesh represents a promising technology for complex ventral and incisional hernia repair (VIHR). Preclinical studies indicate that poly-4-hydroxybutyrate (P4HB) resorbable mesh supports strength restoration of the abdominal wall. This study evaluated outcomes of high-risk subjects undergoing VIHR with P4HB mesh. METHODS: This was a prospective, multi-institutional study of subjects undergoing retrorectus or onlay VIHR. Inclusion criteria were CDC Class I, defect 10-350 cm2, ≤ 3 prior repairs, and ≥ 1 high-risk criteria (obesity (BMI: 30-40 kg/m2), active smoker, COPD, diabetes, immunosuppression, coronary artery disease, chronic corticosteroid use, hypoalbuminemia, advanced age, and renal insufficiency). Physical exam and/or quality of life surveys were performed at regular intervals through 18 months (to date) with longer-term, 36-month follow-up ongoing. RESULTS: One hundred and twenty-one subjects (46M, 75F) with an age of 54.7 ± 12.0 years and BMI of 32.2 ± 4.5 kg/m2 (mean ± SD), underwent VIHR. Comorbidities included the following: obesity (n = 95, 78.5%), hypertension (n = 72, 59.5%), cardiovascular disease (n = 42, 34.7%), diabetes (n = 40, 33.1%), COPD (n = 34, 28.1%), malignancy (n = 30, 24.8%), active smoker (n = 28, 23.1%), immunosuppression (n = 10, 8.3%), chronic corticosteroid use (n = 6, 5.0%), advanced age (n = 6, 5.0%), hypoalbuminemia (n = 3, 2.5%), and renal insufficiency (n = 1, 0.8%). Hernia types included the following: primary ventral (n = 17, 14%), primary incisional (n = 54, 45%), recurrent ventral (n = 15, 12%), and recurrent incisional hernia (n = 35, 29%). Defect and mesh size were 115.7 ± 80.6 and 580.9 ± 216.1 cm2 (mean ± SD), respectively. Repair types included the following: retrorectus (n = 43, 36%), retrorectus with additional myofascial release (n = 45, 37%), onlay (n = 24, 20%), and onlay with additional myofascial release (n = 8, 7%). 95 (79%) subjects completed 18-month follow-up to date. Postoperative wound infection, seroma requiring intervention, and hernia recurrence occurred in 11 (9%), 7 (6%), and 11 (9%) subjects, respectively. CONCLUSIONS: High-risk VIHR with P4HB mesh demonstrated positive outcomes and low incidence of hernia recurrence at 18 months. Longer-term 36-month follow-up is ongoing.

Seroma Formation in Rat Latissimus Dorsi Resection in the Presence of Biologics: The Role of Quilting.

BACKGROUND: Seroma formation is a well-recognized complication associated with many operative procedures. Despite its ubiquity, a lack of definitive scientific understanding of the etiology, natural history, and biochemistry of seromas remains. We endeavored to create and examine seromas in a rat model in the setting of commonly used biologic implants and to examine the role of quilting sutures/mechanical fixation in mitigating seroma development. METHODS: Female Sprague-Dawley rats were assigned to either Quilting or Nonquilting groups then subdivided into one of 3 porcine dermal implant groups (Permacol Surgical Implant, Strattice Reconstructive Tissue Matrix, or XCM Biologic Tissue Matrix) or control group. A 5-cm midline back incision was made, the skin reflected and the latissimus dorsi muscle resected bilaterally. Implants were sutured into the surgical bed using a running suture. The skin of nonquilted rats was closed with a running subcuticular suture. Quilted rats underwent placement of absorbable quilting sutures spaced 2 cm apart between the skin and underlying implant or muscle before skin closure. Postoperatively, rats were monitored for seroma formation with fluid aspirated as needed. At 28 or 90 days, rats were euthanized. Seroma and implants were examined grossly and under light microscopy. RESULTS: Of nonquilted rats, 42/54 (78%) developed seromas compared with 19/46 (41%) of quilted rats (P < 0.05), defined by bursa cavity present at necropsy. When a biologic implant was present, 28/35 (80%) of nonquilted rats developed seromas compared with 12/33 (36%) of quilted rats (P < 0.05). In the control group, 14/19 (74%) of nonquilted rats developed seromas compared with 7/13 (54%) of quilted rats. This difference was not statistically significant. Bursa presence was confirmed histologically in all cases, with no difference in bursa character seen between groups. CONCLUSIONS: This study confirms a reliable rat model of seroma formation, with most of the rats exhibiting at least subclinical seromas. There was no difference in seroma formation rate in the presence of biologic implants, and no differences in bursa character between implants. Mechanical fixation with quilting sutures decreased seroma rate significantly in all subgroups. All rats with seromas at necropsy had histological evidence of a bursa with no difference in appearance between groups.

Cross-linking in biomaterials: a primer for clinicians.

The purpose of this primer is to provide the clinical surgeon with a survey overview of the basic biochemistry of collagen and the methods and rationale of collagen cross-linking in the processing and preparation of bioprosthetics for surgical implantation. The author highlights the critical biologic factors, such as strength over time, integration, and rate, and type of remodeling, that are to an extent controllable by the cross-linking of collagen tissues so that clinicians may be better capable of understanding differences among the devices, which may be more applicable to their clinical indications.

Fleur-de-lis panniculectomy after bariatric surgery: our experience.

BACKGROUND: Plastic surgeons are faced with increasing numbers of patients presenting for insurance-covered skin excision procedures following bariatric surgery. Panniculectomy for symptomatic relief of rashes is commonly performed, but an isolated infraumbilical amputation-type panniculectomy is a highly unaesthetic procedure, leaving many patients deeply dissatisfied. It may be also fraught with complications due to large incisions and potential for dead-space. In these patients, many surgeons avoid the fleur-de-lis panniculectomy, despite the body contour aesthetic advantage, because of increased time, more scarring, and a perceived increase in complications. METHODS: This is a retrospective chart review of 130 consecutive postbariatric surgery patients who had panniculectomy over a 2-year period at our institution. RESULTS: A total of 30 patients underwent a traditional panniculectomy and 100 patients had a fleur-de-lis panniculectomy. Mean weight loss from bariatric surgery to panniculectomy was 58.2 kg, with an average body mass index (BMI) of 30. Fifty-seven patients had additional procedures performed at the time of panniculectomy. Twenty-two patients (17%) had complications, with 5 in the traditional group (17%) and 17 in the fleur-de-lis group (17%) (P = 1.0). Six males (40%) had more complications compared with 18 females (15.7%) (P = 0.034). Patients with BMI <30 had 10 complications compared with patients with BMI ≥30 had 15 complications. CONCLUSIONS: There are many benefits of fleur-de-lis over traditional panniculectomy, even for medical necessity cases. There is limited undermining of tissue which minimizes/eliminates skin necrosis. Our experience with primarily fleur-de-lis panniculectomies shows a complication rate lower than most published data. Fleur-de-lis potentially creates a better symptom correction and cosmetic outcome by resecting maximal skin in both vertical and horizontal directions. These findings must be balanced against a potentially longer operation.

Frontal sinus repair through a frontalis rhytid approach.

Frontal sinus fractures have traditionally been repaired through a bicoronal approach. This incision provides a wide exposure, but is not without complications, particularly in the patient with or at risk for hairline recession. We present a series of 15 patients who underwent open reduction and internal fixation of anterior table frontal sinus fractures through a frontalis rhytid forehead incision and their results based on the scar appearance, forehead contour, frontalis function, sensation and fracture reduction. Paresthesias cranial to the incision in the supraorbital or supratrochlear distribution were noted in 12 of the 15 patients with resolution in all except 1 patient who did not regain sensation at 4 months follow-up. In all patients, satisfactory forehead contour and fracture reduction were achieved, as were scar appearance and frontalis function at 4 months follow-up. We thus recommend this approach in the treatment of anterior table frontal sinus fractures, with special consideration for the patient with or at risk for anterior hairline recession.

Adductor magnus perforator flap revisited: an anatomical review and clinical applications.

BACKGROUND: The adductor magnus musculocutaneous perforator flap is a medial thigh flap whose utility is often overshadowed by that of its anatomic neighbor, the gracilis flap. It has a large, reliable pedicle and associated skin paddle. Few reports have been published describing the use of this flap as a local or free tissue transfer. The purpose of this study is to revisit and further characterize the anatomy of this extremely versatile yet underutilized flap. MATERIALS/METHODS: A total of 13 cadavers (n = 26 thighs) were dissected to identify the musculocutaneous perforators that supply the skin of the posteriomedial thigh. The vascular anatomy was studied using multiple modalities. Based on the anatomic data, a local V-Y advancement flap was designed. A total of 8 patients (n = 10 flaps) underwent reconstruction of locoregional defects. RESULTS: Our anatomic studies confirmed the presence of multiple parallel musculocutaneous perforators that travel through the adductor magnus muscle and course obliquely in a posterior-inferior direction. We found that the primary perforator is reliably found approximately 8 cm distal to the groin crease and 2 cm posterior to the posterior border of the gracilis muscle. We discovered that it is consistently accompanied by a separate perforator located 2 cm distally. Minimal dissection into the muscle revealed a Y-configuration of these 2 perforators. This configuration was present in 100% of the cadaveric dissections and is supplied by the first medial branch of the profunda femoris artery. Computed tomography angiograms depicted vascular arborization of the perforators supplying the flap. Clinical experience showed that complete flap survival was achieved in all of the cases. CONCLUSION: The adductor magnus perforator flap is a reliable flap that offers robust blood supply, through a consistent vascular pedicle, to an extensive skin territory. Our anatomic studies revealed the consistent presence of 2 proximal perforators in the medial thigh that are linked by an intramuscular Y-configuration that provides enhanced blood supply to a local V-Y advancement flap design. The location of the skin paddle on the proximal medial thigh allows for minimal donor-site morbidity as it can be closed primarily with a V-Y advancement flap design, obviating the need for skin grafting.

Assessment of gauze-based negative pressure wound therapy in the split-thickness skin graft clinical pathway-an observational study.

OBJECTIVES: Negative pressure wound therapy (NPWT) is a useful therapy in the preparation of wounds prior to application of a split-thickness skin graft (STSG) both "pregraft" and "postgraft" on top of the STSG. Customarily, a foam-based NPWT has been used, but gauze-based therapy is finding an increasing use. Gauze is easy to apply and forgiving of complicated wound geometries so it can be an ideal material in this indication. The aim of this study was to quantitatively assess the clinical efficacy of gauze-based NPWT as an adjunctive therapy to STSG procedures. METHODS: A prospective, noncomparative, multicenter evaluation was carried out to assess the performance of gauze-based NPWT. Twenty-one patients had NPWT applied prior to definitive closure by STSG or flap techniques (pregraft group). A further 21 patients underwent an STSG procedure and had gauze-based NPWT placed immediately on top of the STSG (postgraft group). Negative pressure was applied at -80 mm Hg. RESULTS: In the pregraft group, NPWT was used for a median of 12 days. Improvement in quality of wound bed with decreased nonviable tissue (from 20% to 0% median wound area) and increased granulation tissue (from 20% to 90% median wound area) was observed. In the postgraft group, median duration of therapy was 5 days at which point median percentage skin graft-take was 96%. CONCLUSIONS: Gauze-based NPWT appears to be an effective addition to the care and management of wounds intended for definitive closure by STSG.

Femur flap for tibial reconstruction: percent circumference required to convey a mechanical advantage over the fibula.

The fibula flap is commonly used to reconstruct the tibia. This has risk of postoperative fracture despite long-term non-weight bearing. A flap using noncircumferential distal femur is proposed. This study is to determine the circumference of femur required to produce greater strength than the fibular flap. Femurs and fibulas were harvested from eight cadavers. The structural strength of fibula and femur flaps was assessed using three-point bend. Compression testing was performed on osteotomized and whole femurs to assess donor site morbidity. The 35% flap (mean maximum force at fracture 869 N) was not significantly stronger than the fibula flap (626 N; P > 0.05). The 40% flap (1225 N) was significantly stronger than the fibula flap ( P < 0.01). There was no significant difference between forces at fracture for whole femurs (3978 N), femurs with 35% osteotomies (3604 N), and femurs with 40% osteotomies (3493 N; P = 0.87). Change occurred in the fracture pattern of femurs following osteotomies. Whole femurs consistently fractured at the femoral neck, and osteotomized femurs consistently fractured obliquely from the osteotomy. A flap consisting of 40% of the circumference of the distal femur exceeds the structural strength of the fibular flap. Taking such a flap changes the femur's structural integrity; fixation may be prudent following harvest.

Use of gauze-based negative pressure wound therapy in a pediatric burn patient.

Negative pressure wound therapy (NPWT) is described as it is used in the treatment of an infant burn victim. This case highlights the ability and techniques used to maintain an airtight dressing seal in the perirectal region. Use of this dressing type post-skin grafting allowed for 100% graft adhesion and no bacterial contamination despite close proximity to the rectum. Favorable experience and outcome with this patient are strong indicators that NPWT should be considered as a viable treatment in pediatric populations and that situations where body contour or fluids may make NPWT difficult to administer should not be a deterrent to therapy.

Salvage of a lower extremity by microsurgical transfer of tibial bone from the contralateral extremity traumatically amputated at the ankle level.

The authors present a case of free vascularized transfer of the tibial bone as an osteomyocutaneous flap based on the posterior tibial vessels. A 42-year-old man presented with severe crush injury to bilateral legs. The left tibial bone and soft tissue defect required reconstruction with an osteomyocutaneous free flap. Since the contralateral leg was traumatically amputated at the level of the ankle, a decision was made to harvest a free tibial osteomyocutaneous flap with below-knee-amputation completed. The transfer was achieved successfully with complete survival of the flap and bony union. This report describes the technical and healing aspects of such a unique transfer which may rarely be indicated.

Characterization of forces on the sternal midline following median sternotomy in a porcine model.

The development of more effective fixation devices for reapproximating and immobilizing the sternum after open-heart surgery is limited by current methods for evaluating these devices. In particular, precise emulation of in vivo sternal loading has not been achieved in controlled model systems. The present study is an initial effort to determine the in vivo loading parameters needed to improve current in vitro and in silico (computational) models. Towards this goal, the direction, magnitude, and distribution of loading along a midline sternotomy were characterized in a porcine model. Two instrumented plating systems were used to measure the forces across the bisected sternum in four anaesthetized Yorkshire pigs during spontaneous breathing, ventilated breathing, and coughing for four treatments: live, cadaveric, embalmed, and refrigerated. Changes in forces incurred by death and embalming were also investigated to evaluate the potential applicability of cadavers as models for testing sternal fixation devices. The magnitudes of the respiratory forces in three orthogonal directions ranged from 0.4 N to 43.8 N, many fold smaller than previously estimated. Dynamic forces were highest in the lateral direction during coughing and low in all directions during normal breathing. No significant differences in force were found between the four treatments, most likely due to the unexpectedly low magnitude of forces in all groups. These results provide the first measurements of in vivo sternal forces and indicate that small cyclic fatigue loads rather than large quasistatic loads should be applied in future model systems to best evaluate the mechanical performance of fixation devices.

Management of incidental fibrous dysplasia of the maxilla in a patient with facial fractures.

We present the case of a 53-year-old man who was involved in a motor vehicle accident. A maxillofacial computed tomography scan revealed a large tumor of the left maxilla as well as multiple facial fractures. The tumor extended from the palate to the orbital floor and from the medial to the lateral wall of the maxillary sinus. We describe the surgical approach as well as the operative management of incidental fibrous dysplasia of the maxilla in a patient with facial fractures.

Remote ischemic preconditioning modulates p38 MAP kinase in rat adipocutaneous flaps.

Ischemic preconditioning has been shown to improve survival of cutaneous flaps. The authors examined the effect of remote ischemic preconditioning (RIPC) on phosphorylation of p38 MAP kinase and related the results to flap survival. Female Wistar rats had 8 x 12-cm abdominal adipocutaneous flaps raised on the medial branch of the superficial epigastric artery. Controls (Group 1) had the flap elevated and the pedicle clamped for 3 hr, then closed with a sheet of plastic between the flap and abdominal wall. Group 2 animals had RIPC by tourniquet on the contralateral hind limb before the flap was dissected. Group 3 animals mimicked Group 2 and also had an infusion of the nitric oxide blocker, N-nitro-L-arginine methyl ester (L-NAME) 5 min prior to the RIPC. Group 4 had the flap elevated prior to the RIPC. All groups except Group 1 had 10 min of RIPC with 30 min of reperfusion, then 3 hr of ischemia. Tissue samples were taken at the distal margins of the flaps before preconditioning and 30 min after preconditioning for detection of p38 MAP kinase and phosphorylated p38 MAP kinase (pp38 MAP kinase). Group 2 flaps (RIPC before flap elevation) exhibited better flap tissue survival and had well-defined phosphorylation of p38 MAP kinase 30 min post RIPC, when compared to the other groups. Pre-infusion with the nitric oxide blocker (Group 3) before RIPC blocked the survival advantage conferred by preconditioning and diminished the phosphorylation of p38 MAP kinase. Tissue from all groups showed very little phosphorylation of p38 MAP kinase following 3 hr of ischemia. Thus, increased tissue survival is correlated with elevated levels of p38 MAP kinase phosphorylation following RIPC. This effect is inhibited by blockade of nitric oxide. Modulation of the p38 MAP kinase pathway may represent a protection pathway for ischemic preconditioning.

A mechanical study of rigid plate configurations for sternal fixation.

Rigid metal plates are a promising alternative to wires for reapproximating the sternum after open-heart surgery due to their potential ability to reduce motion at the wound site and thereby reduce the likelihood of post-operative healing complications. Despite initial clinical success, the use of plates has been limited, in part, by insufficient knowledge about their most effective placement. This study compares the ability of five plate configurations to provide stable closure by limiting sternal separation. Commercially available x-shaped and box-shaped plates were used and combinations of parameters (plate type, location, and number of plates) were investigated in vitro. Lateral distraction tests using controlled, uniform loading were conducted on 15 synthetic sterna and the distractions between separated sternum halves were measured at seven locations. Distractions at the xiphoid, a critical region clinically, varied widely from 0.03 +/- 0.53 mm to 4.24 +/- 1.26 mm depending on all three plate parameters. Of the configurations tested, three x-shaped plates and one box-shaped plate resisted sternal separation most effectively. These results provide the first comparison of plate configurations for stabilizing a sternotomy. However, basic mechanical analyses indicate that sternal loading in vivo is non-uniform; future studies will need to accurately quantify in vivo loading to improve in vitro test methods.

Venous supercharging of heterodigital artery flap.

BACKGROUND: The heterodigital artery island flap is a popular method of reconstruction for finger defects. Postoperative venous congestion is a common problem. METHODS: The authors present a technique to augment venous drainage of the flap. Briefly, the flap is harvested along with a dorsal vein that is then anastomosed to a recipient vein in an end-to-end fashion, after flap transfer and insetting. Using this technique, seven patients were operated on, ranging in age from 5 to 35 years (average age, 23 years). RESULTS: All flaps survived with no postoperative flap congestion, fully satisfying the reconstructive requirements. By this modification, skeletonization of the digital artery of the flap pedicle is safe if that approach is preferred, since there is no need to harvest periarterial fat for venous drainage. CONCLUSIONS: Providing good harmony with conventional methods and microsurgery, inclusion of a vein with the heterodigital artery island flap allows a more reliable and safer reconstructive choice for finger defects. Such a modification converts the unconventional venous circulation of the heterodigital artery island flap to a more physiologic one.

In vitro comparison of wire and plate fixation for midline sternotomies.

BACKGROUND: The incidence of severe sternal wound complications in high-risk cardiac patients presents a significant need for more stabile sternal fixation techniques after median sternotomy procedures. Rigid metal plates, a potential alternative to wire fixation, are thought to promote faster sternal healing by reducing motion at the wound site. The goal of this study was to compare the stability provided by commercially available sternal plates with standard wires using an in vitro model. METHODS: Lateral distraction tests were conducted on bisected polyurethane sternal models fixed with either a standard 7 wire configuration (n = 5) or a 3 plate configuration (n = 3). To assure controlled loading, the sternal models were attached to a computer-controlled test machine by a novel tethering system that distributes the total force (180N) equally to eight locations on the sternum. Stability was defined as the ability to restrict sternal separation at seven locations along the midline quantified using digital image analysis. RESULTS: Our results indicate that rigid plate fixation significantly reduced lateral motion relative to wire fixation. The lower sternal region most noticeably benefited from plate fixation as the splaying observed for wire fixation was reduced. CONCLUSIONS: Under these loading conditions, plating increased stability at the midline compared to wires; this increased stability may facilitate the recovery of high-risk patients undergoing cardiac operation. To enhance in vitro testing methods, future studies should incorporate additional in vivo loading conditions applied to the sternum. Alternate plating configurations should also be examined to further increase stability.

The penile flap in the rat: description and autotransplantation.

Considering both its unique structural and functional properties, the reconstruction of the penis is still a challenging problem in reconstructive surgery. Reconstruction may be required in many situations, including traumas, congenital abnormalities, and female-to-male transsexual surgery. Currently, the only natural reconstructive method for the penis is its microvascular reattachment in amputation cases. In all other situations, and in nonreplantable amputations, there is no alternative but to reconstruct the penis using autologous tissues to create the most similar substitute, hoping for a possible allogeneic transplantation in the future. There are many unresolved issues and unanswered questions related to functional recovery after replantation of the penis. In this study, to overcome these drawbacks and to guide and show the feasibility of allogeneic transplantation of the penis in humans in the future, we describe a penile composite tissue flap based on the internal pudendal artery and its autotransplantation in an economical animal species. Fifty adult male Sprague-Dawley rats weighing 400 to 500 g were used. In 20 rats, the vascular anatomy of the male perineal region was determined by anatomic dissections. Based on this anatomic study, the penile composite flap was created based on the internal pudendal vessels. In 10 rats, the penile flap was raised as an island flap based on its vascular pedicle and replaced in situ. In 10 rats, distant flap transfer was accomplished to determine the feasibility of the flap being transferred as a free flap and to demonstrate the viability of the flap components in a heterotopic region. For this purpose, the flap was transferred to the groin region performing anastomoses between internal pudendal vessels and superficial epigastric vessels. In the control group (n=10), while the same surgical procedure was performed, the flap was transferred to the groin region but no anastomosis was performed. The procedure required approximately 3 to 4 hours of operating time in the free flap group. Five of the animals died in the early postoperative days, while all others survived. Direct observation and microangiography were used to assess the viability of the flaps. On the basis of direct observation on the seventh postoperative day, all the pedicled flaps survived completely. In the free-flap group, all but 1 of the vascularized flaps showed complete survival, whereas all the nonvascularized flaps completely necrosed. The authors conclude that the penile flap of the rat offers the following advantages: (1) the composite tissue flap is harvested from a small animal species, (2) the flap is an exact representation of the clinical original penile composition, (3) it can be transferred as a free flap without the need for an isogeneic animal, (4) the vascular pedicle is consistent and allows for microvascular anastomoses. The flap will provide a means for future physiological studies, especially for replantation cases. The feasible autotransplantation of the penile flap with successful results will also guide researchers towards the future allogeneic transfer of the penis in humans.