Laparoscopically harvested omental flap for chest wall and intrathoracic reconstruction

Bioengineering of vascularized porcine flaps using perfusion-recellularization

Large volume soft tissue defects greatly impact patient quality of life and function while suitable repair options remain a challenge in reconstructive surgery. Engineered flaps could represent a clinically translatable option that may circumvent issues related to donor site morbidity and tissue availability. Herein, we describe the regeneration of vascularized porcine flaps, specifically of the omentum and tensor fascia lata (TFL) flaps, using a tissue engineering perfusion-decellularization and recellularization approach. Flaps were decellularized using a low concentration sodium dodecyl sulfate (SDS) detergent perfusion to generate an acellular scaffold with retained extracellular matrix (ECM) components while removing underlying cellular and nuclear contents. A perfusion-recellularization strategy allowed for seeding of acellular flaps with a co-culture of human umbilical vein endothelial cell (HUVEC) and mesenchymal stromal cells (MSC) onto the decellularized omentum and TFL flaps. Our recellularization technique demonstrated evidence of intravascular cell attachment, as well as markers of endothelial and mesenchymal phenotype. Altogether, our findings support the potential of using bioengineered porcine flaps as a novel, clinically-translatable strategy for future application in reconstructive surgery.

Laparoscopic harvest and free transplantation of great omentum flap for extensive tissue defects in complex wounds

INTRODUCTION

The repair of extensive tissue defects remains a challenge, although great progress has been made in reconstructive surgery. The transplantation of a single huge flap or several flaps in combination will inevitably result in donor-site morbidity. Here we report our experience in the repair of these wounds with laparoscopically harvested great omentum flaps.

METHODS

Twelve patients with extensive tissue defects caused by deep burn injury, avulsion injury, and open fracture underwent free omental flap transplantation and split-thickness skin grafting. The patient demographics, wound characteristics, and complications postsurgical operation were recorded. Prior to omentum flap transplantation, these patients underwent debridement, vacuum sealing drainage treatment, and/or fixation of fractures. All omentum flaps harvested using laparoscopic technique were anastomosed to recipient vessels, and split-thickness skin grafting was performed 14 days after omental flap transplantation.

RESULTS

The mean defect size was 471 cm2 and the mean omental flap size was 751.1 cm2. Among all 12 cases, the omental flaps survived well except for distal partial necrosis in one case. Skin grafting was also achieved in all cases, and all patients achieved complete wound coverage. All donor sites achieved primary healing without major complications. The mean follow-up time was 30 months with satisfactory appearance and functional outcome.

CONCLUSION

For the reconstruction of extensive tissue defects in complex wounds, the free transfer of an omental flap may be an ideal option because of its well-vascularized and pliable tissue with reliable vascular anatomy, as well as minimized donor-site morbidity.

Anterior Chest Wall Reconstruction After Separation of Thoraco-Omphalopagus Conjoined Twins With Cadaveric Rib Grafts and Omental Flap

BACKGROUND

Anterior chest wall defects have a wide range of etiologies in the pediatric population, ranging from infection, tumor, and trauma to congenital diseases. The reconstructive goals include restoring skeletal stability, obliterating dead space, preserving cardiopulmonary mechanics, and protecting vital underlying mediastinal organs. Although various reconstructive methods have been described in the literature, selecting the optimal method is challenging for the growing pediatric skeleton. Here, we report a case of previously thoraco-omphalopagus twins who underwent successful separation and reconstruction and presented for definitive anterior chest wall reconstruction.

METHODS

A pair of previously thoraco-omphalopagus conjoined twins underwent definitive anterior chest wall defect reconstruction using cadaveric ribs and omental flap. Twin A received 2 cadaveric ribs, whereas twin B had a much larger sternal defect that required 3 cadaveric ribs combined with an omental flap for soft tissue chest coverage. Both twins were followed up for 8 months.

RESULTS

Twin A's postoperative course was uneventful, and she was discharged on postoperative day 6. Twin B's course was complicated, and she was discharged on supported ventilation on postoperative day 10. At 8 months postoperatively, both twins healed well, and chest radiographs confirmed the stability of the chest reconstructions. The rib grafts in the twin with a tracheostomy were not mobile, and the patient had a solid sternum with adequate pulmonary expansion. The construct initially did not facilitate pulmonary functioning, but after a healing process, it eventually allowed for the twin with the tracheostomy who required pulmonary assistance to no longer need this device.

CONCLUSIONS

Cryopreserved cadaveric ribs and omental flaps offer safe and reliable reconstructive methods to successfully reconstruct congenital anterior chest wall skeletal defects in the growing pediatric population. The involvement of multidisciplinary team care is key to optimizing the outcomes.

Comorbidity Trends in Patients Requiring Sternectomy and Reconstruction: Updated Data Analysis From 2005 to 2020

INTRODUCTION

Comorbidity trends after median sternectomy were studied at our institution by Vasconze et al (Comorbidity trends in patients requiring sternectomy and reconstruction. Ann Plast Surg. 2005;54:5). Although techniques for sternal reconstruction have remained unchanged, the patient population has become more complex in recent years. This study offers insight into changing trends in this patient population.

METHODS

A retrospective review was performed of patients who underwent median sternectomy followed by flap reconstruction at out institution between 2005 and 2020. Comorbidities, reconstruction method, average laboratory values, and complications were analyzed.

RESULTS

A total of 105 patients were identified. Comorbidities noted were diabetes (27%), immunosuppression (16%), hypertension (58%), renal insufficiency (23%), chronic obstructive pulmonary disease (16%), and tobacco utilization (24%). The most common reconstruction methods were omentum (45%) or pectoralis major flaps (34%). Thirty-day mortality rates were 10%, and presence of at least 1 complication was 34% (hematoma, seroma, osteomyelitis, dehiscence, wound infection, flap failure, and graft exposure). Univariate analysis demonstrated that sex (P = 0.048), renal insufficiency, surgical site complication, wound dehiscence, and flap failure (P < 0.05) had statistically significant associations with mortality. In addition, body mass index, creatinine, and albumin had a significant univariate association with mortality (P < 0.05).

CONCLUSIONS

Similar to the original study, there is an association between renal insufficiency and mortality. However, the mortality rate is decreased to 10%, likely because of improved medical management of patients with increasing comorbidities (80% with greater than one comorbidity). This has led to the increased use of omentum as a first-line option. Subsequent wound dehiscence and flap failure demonstrate an association with mortality, suggesting that increasingly complex patients are requiring a method of reconstruction once used a last resort as a first-line option.

Robotic omental flap harvest for near-total anterior chest wall coverage: a potential application of robotic techniques in plastic and reconstructive surgery

We present the robotic harvest of a pedicled omentum flap for reconstruction of a near-total anterior chest wall defect. The patient was a 68-year-old woman with recurrent secondary chest wall angiosarcoma after previous mastectomy and radiation therapy. She underwent neoadjuvant chemotherapy and radiation, followed by wide radical chest wall resection with a final defect size of 15×35 cm. A one-stage reconstruction was performed with an omentum flap harvested by robotic technique and split-thickness skin grafts from thigh donor sites. The patient healed with minimal complications. Our case supports more widespread application of robotics in plastic and reconstructive surgery.

Omental Flap Coverage for Management of Thoracic Aortic Graft Infection

BACKGROUND

Since the first reported use of prosthetic aortic grafts, infection has remained a feared complication. Pedicled omentum is the preferred flap in managing thoracic aortic graft infection (TAGI); however the literature is sparse. The authors present their experience with TAGI managed with pedicled omental flaps.

METHODS

A single-institutional review from 2007 to 2018 was performed to analyze postoperative outcomes of omental flap reconstruction, performed by 2 surgeons, after a confirmed diagnosis of TAGI. The primary outcomes of overall complication rate, 30-day mortality, and in-hospital mortality were evaluated with univariate analysis.

RESULTS

Twenty patients requiring omental flap reconstruction after TAGI met inclusion criteria. The patient cohort included 14 men and 6 women with a mean age of 60.6 ± 12.9 years and a mean Charlson comorbidity index of 3.3 ± 2.1. Nine patients (45%) received omental flap reconstruction at the time of incipient TAGI surgical management by the cardiothoracic surgery team, whereas 11 patients received delayed reconstruction (mean, 6.22 days [range, 1-27]). The most common complications were graft leak (20%) and pseudoaneurysm (25%), with only 1 patient developing recurrent infection. Overall 30-day mortality was 20%. Chronic obstructive pulmonary disease and delayed omental flap reconstruction were associated with 30-day mortality (P = .04). Four of 11 patients (36.4%) who received delayed omental flap reconstruction died within 30 days, whereas 0 of 9 patients (0%) in the immediate omental coverage group died within 30 days (P = .043).

CONCLUSIONS

High mortality rates associated with TAGI exemplify the challenges associated with this disease process and patient population. Pedicled omentum is a safe adjunct with promising results to the management of TAGI while significantly reducing the risk of reinfection.

Robotic harvesting of the omental flap: a case report and mini-review of the use of robots in reconstructive surgery

This study describes the robotic harvesting of a free omental flap. The patient was a 58-year-old man who had undergone several previous operations due to osteomyelitis caused by trauma. There was a non-healing wound and purulent discharge in the distal pretibial region. The flap was harvested based on the right gastroepiploic artery using robotic facilities only. The flap was then transferred to the debrided defect in the pretibial region. Anastomoses were performed between the posterior tibial vessels and the pedicle of the flap. A split thickness skin graft was used to cover the omental flap. The operation lasted 2.5 h in total, including flap harvesting, microvascular anastomoses, inset and skin grafting. The postoperative period was uneventful and the patient was discharged on the 12th day postoperatively. The reliability of the technique is discussed in this report, together with a brief review of the use of robot surgery in reconstructive surgery in the literature.

Electron microscopic observation of human auricular chondrocytes transplanted into peritoneal cavity of nude mice for cartilage regeneration

Restoration of damaged cartilage tissue has been deemed futile with current treatments. Although there have been many studies on cartilage regeneration thus far, there is no report that chondrocytes were completely re-differentiated in vitro. The clarification of cellular composition and matrix production during cartilage regeneration must be elucidated to fabricate viable mature cartilage in vitro. In order to achieve this aim, the chondrocytes cultured on coverslips were transplanted into the peritoneal cavities of mice. At different time points post-transplantation, the cartilage maturation progression and cells composing the regeneration were examined. Cartilage regeneration was confirmed by hematoxylin & eosin (HE) and toluidine blue staining. The maturation progression was carefully examined further by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). At the first and second week time points, various cell shapes were observed using SEM. Chronologically, by the third week, the number of fibers increased, suggesting the progression of extracellular matrix (ECM) maturation. Observation through TEM revealed the chondrocytes located in close proximity to various cells including macrophage-like cells. On the second week, infiltration of lymphocytes and capillary vessels were observed, and after the third week, the chondrocytes had matured and were abundantly releasing extracellular matrix. Chronological observation of transplanted chondrocytes by electron microscopy revealed maturation of chondrocytes and accumulation of matrix during the re-differentiation process. Emerging patterns of host-derived cells such as macrophage-like cells and subsequent appearance of lymphocytes-like cells and angiogenesis were documented, providing crucial context for the identification of the cells responsible for in vivo cartilage regeneration.

Vascularisation for cardiac tissue engineering: the extracellular matrix

Cardiovascular diseases present a major socio-economic burden. One major problem underlying most cardiovascular and congenital heart diseases is the irreversible loss of contractile heart muscle cells, the cardiomyocytes. To reverse damage incurred by myocardial infarction or by surgical correction of cardiac malformations, the loss of cardiac tissue with a thickness of a few millimetres needs to be compensated. A promising approach to this issue is cardiac tissue engineering. In this review we focus on the problem of in vitro vascularisation as implantation of cardiac patches consisting of more than three layers of cardiomyocytes (> 100 μm thick) already results in necrosis. We explain the need for vascularisation and elaborate on the importance to include non-myocytes in order to generate functional vascularised cardiac tissue. We discuss the potential of extracellular matrix molecules in promoting vascularisation and introduce nephronectin as an example of a new promising candidate. Finally, we discuss current biomaterial- based approaches including micropatterning, electrospinning, 3D micro-manufacturing technology and porogens. Collectively, the current literature supports the notion that cardiac tissue engineering is a realistic option for future treatment of paediatric and adult patients with cardiac disease.

Sternal reconstruction after post-sternotomy mediastinitis

Background

Deep sternal wound complications are uncommon after cardiac surgery. They comprise sternal dehiscence, deep sternal wound infections and mediastinitis, which will be treated as varying expressions of a singular pathology for reasons explained in the text.

Methodology and review

This article reviews the definition, prevalence, risk factors, prevention, diagnosis, microbiology and management of deep sternal wound infections and mediastinitis after cardiac surgery. The role of negative pressure wound therapy and initial and delayed surgical management is discussed with special emphasis on plastic techniques with muscle and omental flaps. Recent advances in reconstructive surgery are presented.

Conclusions

Deep sternal wound complications no longer spell debilitating morbidity and high mortality. Better understanding of risk factors that predispose to deep sternal wound complications and general improvement in theatre protocols for asepsis have dramatically reduced the incidence of deep sternal wound complications. Negative pressure wound therapy and appropriately timed and staged muscle or omental flap reconstruction have transformed the outcomes once these complications occur.

[Laparoscopic-assisted harvesting of omental flap in chest wall reconstruction for deep sternal wound infection]

AIM

To present an experience of laparoscopic-assisted harvesting of omental flap in chest wall reconstruction for deep sternal wound infection.

MATERIAL AND METHODS

It was made a prospective analysis of 14 patients aged 39-85 years after laparoscopic-assisted harvesting of omental flap in chest wall reconstruction for the period December 2014 - November 2016. Men/women ratio was 10/4. All patients had deep sternal wound infection grade IV (Oakley-Wright classification).

RESULTS

Postoperative complications were observed in 2 (14.3%) of 14 (95% CI: 4.0-39.9%) cases that did not require re-operation. There were no 30-day postoperative mortality and significant complications as acute intestinal obstruction, postoperative ventral herniation and transplant rejection. Mean postoperative hospital-stay was 10.5 (9; 13) days.

CONCLUSION

Laparoscopic-assisted harvesting of omental flap is safe method for chest wall reconstruction in patients with severe sternal wound infection associated with soft tissue deficiency and high risk of local complications (bleeding, etc.). Laparoscopy significantly reduces incidence of postoperative complications after omental flap transposition and is feasible in majority of patients.

Chest wall reconstruction after extended resection

Extensive chest wall resection and reconstruction is a challenging procedure that requires a multidisciplinary approach, including input from thoracic surgeons, plastic surgeons, neurosurgeons, and radiation oncologists. The primary goals of any chest wall reconstruction is to obliterate dead space, restore chest wall rigidity, preserve pulmonary mechanics, protect intrathoracic organs, provide soft tissue coverage, minimize deformity, and allow patients to receive adjuvant radiotherapy. Successful chest wall reconstruction requires the re-establishment of skeletal stability to prevent chest wall hernias, avoids thoracoplasty-like contraction of the operated side, protects underlying viscera, and maintain a cosmetically-acceptable appearance. After skeletal stability is established, full tissue coverage can be achieved using direct closure, skin grafts, local advancement flaps, pedicled myocutaneous flaps, or free flaps. This review examines the indications for chest wall reconstruction and describes techniques for establishment of chest wall rigidity and soft tissue coverage.

Comprehensive review of vascularized lymph node transfers for lymphedema: Outcomes and complications

INTRODUCTION

Lymphedema remains a challenging clinical problem. A new field of lymphatic surgery using micro and super microsurgery techniques is a rapidly advancing field aimed to treat recalcitrant cases. The objective of this study was to evaluate outcomes and complications of vascularized lymph node transfer (VLNT). Several early preliminary studies have reported promising outcomes, but they are limited by small numbers, short follow-up, and are inconsistent in addressing the origin and recipient site of the transferred lymph nodes as well as the donor site morbidity.

METHODS

A review of literature was conducted using PubMed-MEDLINE, EMBASE for key words vascularized lymph node transfer (also autologous, lymph node transplant). Only human studies were included.

RESULTS

A total 24 studies encompassing 271 vascularized lymph node transfers were included. The inguinal nodes were the most commonly used donor site followed by the lateral thoracic lymph nodes. The lateral thoracic lymph nodes were the least effective and had the highest complication rates (27.5%) compared to other lymph node donor sites (inguinal: 10.3% and supraclavicular: 5.6%). Upper extremity lymphedema responded better compared to lower extremity (74.2 vs. 53.2%), but there was no difference in placing the lymph nodes more proximally versus distally on the extremity (proximal: 76.9% vs. distal: 80.4%).

CONCLUSION

Vascularized lymph node transfer for lymphedema treatment is a promising operative technique showing beneficial results in early but also in advanced stage lymphedema. This physiologic surgical procedure should be included in a modern reconstructive concept for lymphedema treatment. © 2016 Wiley Periodicals, Inc. Microsurgery 38:222-229, 2018.

Important considerations in chest wall reconstruction

Chest wall reconstruction represents one of the most challenging tasks in plastic surgery. Over the past several decades, a more profound understanding of surgical anatomy and physiology along with tremendous advances in surgical technique have resulted in substantial improvements in postoperative outcomes. Conceptually, the reconstructive goals include dead space obliteration, restoration of skeletal stability with protection of intrathoracic structures, and stable soft tissue coverage. Ideally, these goals are achieved with minimal aesthetic deformity. J. Surg. Oncol. 2016;113:913-922. © 2016 Wiley Periodicals, Inc.

Breast necrosis secondary to vasopressor extravasation: management using indocyanine green angiography and omental flap closure

Extravasation is a rare but serious complication of vasopressor administration. A 60-year-old female who underwent ascending and hemiarch repair of the aorta along with aortic valve replacement developed extensive right breast and chest wall necrosis after vasopressor extravasation from an internal jugular vein central line. The patient underwent a total mastectomy due to deep tissue necrosis detected by laser-assisted indocyanine green dye angiography, and eventually required omental flap reconstruction to obtain adequate sternal coverage. This case represents a previously unreported complication of internal jugular central line extravasation of vasopressors with resultant breast and chest wall necrosis, and highlights the utility of the omentum in chest wall reconstruction.

Sternal reconstruction with omental and pectoralis flaps: a review of 415 consecutive cases

BACKGROUND

Sternal wound infections are a life-threatening complication of cardiovascular surgery, and management can present a great challenge for the plastic surgeon. Successful treatment involves a multidisciplinary approach, immediate detection, meticulous debridement, and delivery of vascularized tissue to the infected wound bed.

METHODS

Twenty-nine years experience of a single surgeon in 415 sternal wound reconstructions is retrospectively analyzed. Flap choice was based on the amount of vascularized tissue required. Low-risk, early infections were treated with debridement and a single flap. Large, high-risk wounds were treated with multiple debridements and covered with a combination of flaps to reduce infection and eliminate dead space.

RESULTS

Immediate wound closure with aggressive debridement and flap coverage in a single-stage early in the series (first 12 patients, 1980-1981) led to a mortality rate of 25% due to sepsis and cardiovascular instability. Thereafter, treatment was altered, and patient stability and wound preparation were emphasized, often requiring multiple debridements (91% of all patients). Nine percent of patients, with early low-risk infections, underwent single-stage rewiring and coverage with pectoralis or omental flaps. Coverage of multiple debrided purulent wounds was performed using pectoralis major flap (37% of total number of patients), omentum (18%), a pectoralis/omentum combination (34%), or rectus abdominis flap (2%). A multistage approach and use of 2 flaps for coverage resulted in a 1.5% mortality due to sepsis, 2.5% infection rate, 1.5% skin necrosis rate, and 1.5% hematoma/seroma rate. The use of multiple flaps in large, complex wounds resulted in a complication rate similar to smaller wounds covered with a single flap. In all, 3.5% of the patients required a salvage operation with alternate flaps.

CONCLUSION

This large series demonstrates the importance of early detection of infection, meticulous staged debridement of nonviable tissue, and elimination of dead space with multiple vascularized flaps.

Uncommon flaps for chest wall reconstruction

The omentum, external oblique musculocutaneous, and thoracoepigastric flaps are uncommonly used for chest wall reconstruction. Nevertheless, awareness and knowledge of these flaps is essential for reconstructive surgeons because they fill specific niche indications or serve as lifeboats when workhorse flaps are unavailable. The current report describes the anatomic basis, technical aspects of flap elevation, and indications for these unusual flaps.

A difficult case: omental transposition flap reconstruction of a large radionecrotic axillary ulcer in a patient with extensive previous abdominal surgery

Radionecrotic ulcers due to breast cancer treatment is a highly morbid and disabling condition, causing pain, malodour, need for frequent dressings, reduced range of shoulder movements and an unacceptable cosmetic appearance. In patients with radiotherapy to the chest and/or axilla and general poor health the usual reconstructive options may not be suitable due to regional tissue damage and inappropriate long anaesthetic time, respectively. Described procedures include the pedicled latisimus dorsi flap, transverse rectus abdominal flap (TRAM) and omental transposition flap, as well as free tissue transfer (e.g. free TRAM, DIEP). We report a case of a morbidly obese female patient presenting with a large radionecrotic ulcer in her left axilla, following mastectomy, axillary clearance and local radiotherapy to left chest and axilla for breast cancer. She underwent reconstruction using an omental transposition flap, despite previous abdominal surgery.

Omentum-wrapped scaffold with longitudinally oriented micro-channels promotes axonal regeneration and motor functional recovery in rats

Background

Tissue-engineered nerve scaffolds hold great potential in bridging large peripheral nerve defects. However, insufficient vascularization of nerve scaffolds limited neural tissues survival and regeneration, which hampered the successful implantation and clinical application of nerve scaffolds. The omentum possesses a high vascularization capacity and enhances regeneration and maturation of tissues and constructs to which it is applied. However, combined application of nerve scaffolds and omentum on axonal regeneration and functional recovery in the treatment of large peripheral nerve defects has rarely been investigated thus far.

Methods

In the present study, an omentum-wrapped collagen-chitosan scaffold was used to bridge a 15-mm-long sciatic nerve defect in rats. Rats that received nerve autografts or scaffolds alone were served as positive control or negative control, respectively. The axonal regeneration and functional recovery were examined by a combination of walking track analysis, electrophysiological assessment, Fluoro-Gold (FG) retrograde tracing, as well as morphometric analyses to both regenerated nerves and target muscles.

Findings

The results demonstrated that axonal regeneration and functional recovery were in the similar range between the omentum-wrapping group and the autograft group, which were significantly better than those in the scaffold alone group. Further investigation showed that the protein levels of vascular endothelial growth factor (VEGF), brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF) were significantly higher in the omentum-wrapping group than those in the scaffold alone group in the early weeks after surgery.

Conclusion

These findings indicate that the omentum-wrapped scaffold is capable of enhancing axonal regeneration and functional recovery, which might be served as a potent alternative to nerve autografts. The beneficial effect of omentum-wrapping on nerve regeneration might be related with the proteins produced by omentum.

Muscle and omental flaps for chest wall reconstruction

Reconstruction of the chest wall represents an important part of a patient's treatment following resection of various thoracic tumors. Many different types of flaps, including both pedicled and free flaps, have been described for use in chest wall reconstruction. These reconstructions are most effectively managed with a multidisciplinary approach involving plastic and cardiothoracic surgery. The pectoralis major, latissimus dorsi, rectus abdominis, trapezius, and external oblique muscles and the omentum are all local options that can play an important role in the reconstruction of the chest wall.

Omental transposition flap for sternal wound reconstruction in diabetic patients

In 2004, we published our 12-year experience with tissue transfer for deep sternal wound infection after median sternotomy, finding increased rates of reoperation for diabetic patients. Therefore, we decided to alter our treatment approach to diabetic patients to include sternal debridement followed by omental transposition. Eleven diabetic patients underwent omental transposition by our division during the study period. Hospital records were retrospectively reviewed to determine outcomes and complications. We found that diabetic patients treated after implementation of the new treatment approach were 5.4 times less likely to require reoperation for sternal wound management than were patients in the previous series, most of whom had been treated with pectoralis muscle flaps (95% confidence interval, 0.5- 50.5). By altering our treatment approach to use omental transposition as the initial surgical therapy, we were able to demonstrate a trend toward decreased need for flap revision in diabetic patients.

Enhancing clinical islet transplantation through tissue engineering strategies

Clinical islet transplantation (CIT), the infusion of allogeneic islets within the liver, has the potential to provide precise and sustainable control of blood glucose levels for the treatment of type 1 diabetes. The success and long-term outcomes of CIT, however, are limited by obstacles such as a nonoptimal transplantation site and severe inflammatory and immunological responses to the transplant. Tissue engineering strategies are poised to combat these challenges. In this review, emerging methods for engineering an optimal islet transplantation site, as well as novel approaches for improving islet cell encapsulation, are discussed.

Development of a Seeded Scaffold in the Great Omentum: Feasibility of an in vivo Bioreactor for Bladder Tissue Engineering

OBJECTIVES

Tissue engineering is very promising in bladder reconstruction. However, one of the main problems is to limit the development of ischaemic fibrosis during tissue maturation. We describe a model using the omentum as an in vivo bioreactor for a previously seeded scaffold.

METHODS

Bladder biopsies were taken from five female pigs, from which both urothelial and smooth muscle cells cultures were made. These cultured cells were used to seed a sphere-shaped small intestinal submucosa (SIS) matrix, which was transferred into the omentum after 3 wk of cell growth. The grafts were harvested 3 wk later and histologic, immunohistochemical, and functional studies were performed.

RESULTS

We obtained a highly vascularized tissue-engineered construct that contracted in response to acetylcholine stimulation. The wall thickness was 4mm, on average. Histologic and immunostaining analysis of the construct confirmed the presence of a multilayer urothelium on the luminal aspect and deeper fascicles organised tissue composed of differentiated smooth muscle cells and mature fibroblasts without evidence of inflammation or necrosis. Large- and small-diameter vessels were clearly identified histologically in the tissue obtained.

CONCLUSION

The omentum permitted in vivo maturation of seeded scaffolds with the development of a dense vascularisation that is anticipated to prevent fibrosis and loss of contractility. This in vivo maturation into the omentum could be the first step before in situ implantation of the construct.

Combined Laparoscopically Harvested Omental Flap With Meshed Skin Grafts and Vacuum-Assisted Closure for Reconstruction of Complex Chest Wall Defects

BACKGROUND

Chest wall reconstruction after radiation damage is a challenge in oncologic and plastic surgery. The defect can be reconstructed with laparoscopically harvested omental flap and meshed skin grafts. Our aim was to evaluate the use of vacuum-assisted closure (V.A.C.) in combination with laparoscopically harvested omental flap and meshed skin graft for treating these complex wounds.

METHODS

Between October 2003 and December 2004, 11 patients underwent a chest wall reconstruction with laparoscopic omentoplasty and V.A.C. treatment of severe chest wall radionecrosis after breast cancer treatment (n = 10) or for locally advanced breast cancer treated first by irradiation (n = 1).

RESULTS

Laparoscopic harvesting was uneventful in 10 cases. One patient had a laparoscopic transverse colic resection because of a middle colic artery injury. Mean time of the laparoscopic procedure was 53 minutes (range: 35-120). Wound surface area averaged 360 cm (range: 80-750). The mean duration of V.A.C. treatment was 9.3 days (range: 6-16). Nine patients showed primary wound healing without adverse events. Complications occurred in 3 patients. One developed a pulmonary infection and died after healing during the postoperative course. One presented a partial flap loss, leading to delayed healing after 45 days. One patient with severe radiation damage and a complete brachial plexus paralysis required a shoulder amputation after an extensive necrosis. All but 1 patient are alive and resumed their normal daily activities.

CONCLUSIONS

Combination of laparoscopic omentoplasty and V.A.C. can successfully be used for reconstruction of complex chest wall radiation damage.

Reconstruction of the chestwall and thorax

Chest wall reconstructions can be complex and challenging procedures and may require a multidisciplinary approach. The most common indications for chest wall reconstruction are the repair of defects due to tumor ablation, infection, radiation necrosis, congenital deformities, and trauma. Flap reconstruction by plastic surgery is often required when skin is removed as part of the chest wall resection or when radiation therapy is given pre- or post-operatively. Tissue flaps may be needed to provide vascularized tissue over alloplastic materials used to stabilize the chest wall, to cover vital structures of the chest cavity, to fill dead space, and to improve cosmesis.

Laparoscopic Greater Omentum Harvesting with Split-Thickness Skin Grafting for Sternal Wound Dehiscence

Sternal wound dehiscence is a serious complication occasionally requiring soft tissue coverage. The greater omentum typically has been used as a last resort because of the underlying morbidity from a laparotomy. We present a case in which a laparoscopically created omental flap with subsequent split-thickness skin grafting was used to correct a large soft tissue defect that occurred after sternal wound dehiscence developed. A nonambulatory 49-year-old man who underwent coronary artery bypass grafting developed sternal wound dehiscence. Because a large soft tissue defect developed after multiple debridements, soft tissue coverage was required. A laparoscopically harvested omental flap spared this man's upper extremity musculature and provided a soft tissue bed for split-thickness skin grafting. This case helps to establish the role of laparoscopically harvested omentum. If the results suggested by this case are confirmed in a large series, omental flaps should be considered as options of first choice in the management of sternal wound dehiscence.