Abdominal wall reconstruction after temporary abdominal wall closure in trauma patients

The temporary abdominal closure techniques used for trauma patients: a systematic review and meta-analysis

Purpose

The choice of temporary abdominal closure (TAC) method affects the prognosis of trauma patients. Previous studies on TAC are challenging to extrapolate due to data heterogeneity. We aimed to conduct a systematic review and comparison of various TAC techniques.

Methods

We accessed web-based databases for studies on the clinical outcomes of TAC techniques. Recognized techniques, including negative-pressure wound therapy with or without continuous fascial traction, skin tension, meshes, Bogota bags, and Wittman patches, were classified via a method of closure such as skin-only closure vs. patch closure vs. vacuum closure; and via dynamics of treatment like static therapy (ST) vs. dynamic therapy (DT). Study endpoints included in-hospital mortality, definitive fascial closure (DFC) rate, and incidence of intraabdominal complications.

Results

Among 1,065 identified studies, 37 papers comprising 2,582 trauma patients met the inclusion criteria. The vacuum closure group showed the lowest mortality (13%; 95% confidence interval [CI], 6%-19%) and a moderate DFC rate (74%; 95% CI, 67%-82%). The skin-only closure group showed the highest mortality (35%; 95% CI, 7%-63%) and the highest DFC rate (96%; 95% CI, 93%-99%). In the second group analysis, DT showed better outcomes than ST for all endpoints.

Conclusion

Vacuum closure was favorable in terms of in-hospital mortality, ventral hernia, and peritoneal abscess. Skin-only closure might be an alternative TAC method in carefully selected groups. DT may provide the best results; however, further studies are needed.

Management of the Open Abdomen after Liver Transplantation

INTRODUCTION

The optimal management of the open abdomen (OA) after liver transplantation (LT) is unclear. The negative pressure wound therapy (NPWT) has been shown to be safe and can increase the chance for early fascial closure in trauma or septic patients. However, little data are available on the specific setting of LT. We aimed to report our experience of OA after LT, marked by the recent use of NPWT.

METHODS

All patients with postponed wall closure after LT, from 2002 to 2014, in a single institution were included and retrospectively analyzed. Our management of OA after LT has shifted from skin-only closure (SOC) followed by abdominal wall reconstruction at a distance to the use of NPWT with early fascial closure.

RESULTS

Of the 1559 LTs performed during the study period, immediate abdominal wall closure at the end of transplantation could not be achieved in 46 (2.9%) patients. Of them, SOC was performed in 22 (47.8%) patients, whereas vacuum-assisted closure (VAC) therapy was used in 24 (52.1%) patients. The comprehensive complication indexes (CCI) were similar [CCI: 66 (0-100) in the SOC group vs. 56 (0-100) in the VAC group; p = 0.55]. No evisceration or fistula occurred in both groups. One (4.2%) postoperative bleeding case was reported in the VAC group. Early fascial closure was achieved within a median of 5.5 days (1-12) for the 24 patients (100%) of the VAC group. In four of them, a biological mesh was necessary. Only nine patients (52.9%) of the survivors in the SOC group underwent abdominal reconstruction.

CONCLUSION

The NPWT in patients with OA after LT enables early fascial closure with limited morbidity provided a specific attention is given to the risk of bleeding. These results support the use of NPWT as the first option in OA patients after LT.

Complications and Mortality Associated with Temporary Abdominal Closure Techniques: A Systematic Review and Meta-Analysis

Temporary abdominal closure (TAC) techniques are routinely used in the open abdomen. Ideally, they should prevent evisceration, aid in removal of unwanted fluid from the peritoneal cavity, facilitate in achieving safe definitive fascial closure, as well as prevent the development of intra-abdominal complications. TAC techniques used in the open abdomen were compared with negative pressure wound therapy (NPWT) to identify which was superior. A systematic review was conducted using the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines involving Medline, Excerpta Medica, Cochrane Central Register of Controlled Trials, Cumulative Index to Nursing and Allied Health Literature, and Clinicaltrials.gov. All studies describing TAC technique use in the open abdomen were eligible for inclusion. Data were analyzed per TAC technique in the form of a meta-analysis. A total of 225 articles were included in the final analysis. A meta-analysis involving only randomized controlled trials showed that NPWT with continuous fascial closure was superior to NPWT alone for definitive fascial closure [mean difference (MD): 35% ± 23%; P = 0.0044]. A subsequent meta-analysis involving all included studies confirmed its superiority across outcomes for definitive fascial closure (MD: 19% ± 3%; P < 0.0001), perioperative (MD: -4.0% ± 2.4%; P = 0.0013) and in-hospital (MD: -5.0% ± 2.9%; P = 0.0013) mortality, entero-atmospheric fistula (MD: 22.0% ± 1.8%; P = 0.0041), ventral hernia (MD: -4.0% ± 2.4%; P = 0.0010), and intra-abdominal abscess (MD: -3.1% ± 2.1%; P = 0.0044). Therefore, it was concluded that NPWT with continuous fascial traction is superior to NPWT alone.

Abdominal Wall Reconstruction After Temporary Abdominal Closure: A Ten-Year Review

Abdominal wall reconstruction (AWR) is often required for hernias created after temporary abdominal closure (TAC). Demographic and clinical data from patients undergoing TAC and AWR between January 1, 1992, and December 31, 2002, were collected and univariate analysis performed. Temporary abdominal closure and AWR were performed in 21 patients. Complications developed in 12 patients (57.1%) after TAC; associated risk factors were mesh placement ( P = .04) and skin grafting ( P = .04). Successful AWR included mesh (n = 6), component separation (n = 6), primary repair (n = 4), and 3 combination techniques. Six patients (28.6%) developed intraoperative complications, and 14 (66.7%) developed postoperative complications. Intraoperative complications were increased in patients with tissue expanders ( P = .01). Postoperative complications ( P = .04) were less likely with component separation. The complication rate with TAC and AWR is high. Tissue expanders are associated with an increased risk of intraoperative complications with AWR, whereas component separation is associated with a reduction in postoperative complications.

Comparison of Outcomes between Early Fascial Closure and Delayed Abdominal Closure in Patients with Open Abdomen: A Systematic Review and Meta-Analysis

Up to the present, the optimal time to close an open abdomen remains controversial. This study was designed to evaluate whether early fascial abdominal closure had advantages over delayed approach for open abdomen populations. Medline, Embase, and Cochrane Library were searched until April 2013. Search terms included “open abdomen,” “abdominal compartment syndrome,” “laparostomy,” “celiotomy,” “abdominal closure,” “primary,” “delayed,” “permanent,” “fascial closure,” and “definitive closure.” Open abdomen was defined as “fail to close abdominal fascia after a laparotomy.” Mortality, complications, and length of stay were compared between early and delayed fascial closure. In total, 3125 patients were included for final analysis, and 1942 (62%) patients successfully achieved early fascial closure. Vacuum assisted fascial closure had no impact on pooled fascial closure rate. Compared with delayed abdominal closure, early fascial closure significantly reduced mortality (12.3% versus 24.8%, RR, 0.53, P < 0.0001) and complication incidence (RR, 0.68, P < 0.0001). The mean interval from open abdomen to definitive closure ranged from 2.2 to 14.6 days in early fascial closure groups, but from 32.5 to 300 days in delayed closure groups. This study confirmed clinical advantages of early fascial closure over delayed approach in treatment of patients with open abdomen.

[Abdominal wall closure by incisional hernia and herniation after laparostoma]

As hernias and abdominal wall defects have a variety of etiologies each with its own complications and comorbidities in various constellations, efficient treatment requires patient-oriented management. There is no recommended standard treatment and the very different clinical pictures demand an individualized interdisciplinary approach. Particularly in the case of complicated hernias, the planning of the operation should focus on the problems posed by the individual patient. Treatment mainly depends on the etiology of the hernia, immediate or long-term complications and the efficiency of individual repair techniques. Abdominal wall repair for recurrent herniation requires direct closure of the fascia generally using the sublay technique with a lightweight mesh. It is still unclear whether persistent inflammation, mesh dislocation, fistula formation or other long-term complications are due to certain materials or to the surgical technique. With mesh infections it has been shown to be advantageous to remove a polytetrafluoroethylene (PTFE) mesh, while the combination of systemic and local treatment appears to suffice for a polypropylene or polyester mesh. Heavier meshes in the sublay position or plastic reconstruction with autologous tissue are indicated as substitutes for the abdominal wall for giant hernias, repeated recurrences and large abdominal wall defects. A laparostoma is increasingly more often created to treat septic intra-abdominal processes but is very often responsible for a complicated hernia. If primary repair of the abdominal wall is not an option, resorbable material or split skin is used for coverage under the auspices of a planned hernia repair.

Temporary closure of the open abdomen: a systematic review on delayed primary fascial closure in patients with an open abdomen

Background

This study was designed to systematically review the literature to assess which temporary abdominal closure (TAC) technique is associated with the highest delayed primary fascial closure (FC) rate. In some cases of abdominal trauma or infection, edema or packing precludes fascial closure after laparotomy. This “open abdomen” must then be temporarily closed. However, the FC rate varies between techniques.

Methods

The Cochrane Register of Controlled Trials, MEDLINE, and EMBASE databases were searched until December 2007. References were checked for additional studies. Search criteria included (synonyms of) “open abdomen,” “fascial closure,” “vacuum,” “reapproximation,” and “ventral hernia.” Open abdomen was defined as “the inability to close the abdominal fascia after laparotomy.” Two reviewers independently extracted data from original articles by using a predefined checklist.

Results

The search identified 154 abstracts of which 96 were considered relevant. No comparative studies were identified. After reading them, 51 articles, including 57 case series were included. The techniques described were vacuum-assisted closure (VAC; 8 series), vacuum pack (15 series), artificial burr (4 series), Mesh/sheet (16 series), zipper (7 series), silo (3 series), skin closure (2 series), dynamic retention sutures (DRS), and loose packing (1 series each). The highest FC rates were seen in the artificial burr (90%), DRS (85%), and VAC (60%). The lowest mortality rates were seen in the artificial burr (17%), VAC (18%), and DRS (23%).

Conclusions

These results suggest that the artificial burr and the VAC are associated with the highest FC rates and the lowest mortality rates.

The Wittmann Patch s a temporary abdominal closure device after decompressive celiotomy for abdominal compartment syndrome following burn

BACKGROUND

Abdominal compartment syndrome is frequently the result of aggressive fluid resuscitation after burn. Management of the open abdomen following decompressive celiotomy is a major problem.

METHODS

From 2004 to mid-2005, six patients required decompressive celiotomy after developing abdominal compartment syndrome as a result of burn. A Wittmann Patch as used to close the abdominal wound. Patients were re-explored when clinical parameters improved and the abdomen was closed, with long-term follow-up for the abdominal wound.

RESULTS

Of the six patients, five had thermal injury and one had electrical injury. The mean total body surface area affected for thermal burn was 78% and for electrical burn was 37%. Diagnosis of abdominal compartment syndrome was based on elevated bladder pressure and organ dysfunction. The patients were treated with decompressive celiotomy and Wittmann Patch closure. Survivors subsequently underwent primary abdominal closure, with no evidence of ventral hernia at long-term follow-up.

CONCLUSION

In burn cases with abdominal compartment syndrome, a Wittmann Patch ay prove a helpful method of temporary abdominal closure, followed by primary closure with no complications.

Reconstrução abdominal tardia sem tensão após laparostomia: uma nova técnica

OBJETIVO: A reconstrução abdominal tardia após laparostomia é sempre um procedimento desafiador para o cirurgião devido à necessidade de se corrigir um grande defeito na parede abdominal anterior, o que habitualmente demanda a lise de extensas aderências entre alças intestinais e o tecido cicatricial, sem que a hérnia incisional seja o resultado final. Neste trabalho, propomos uma técnica simples e inédita para esta reconstrução abdominal, sem tensão, utilizando tela de polipropileno sobre o tecido de granulação, sem necessidade de qualquer dissecção intra-peritoneal. MÉTODO: Descrição da técnica e estudo prospectivo de 17 pacientes submetidos à mesma entre 1998 e 2005. Foram analisados; a causa da laparostomia, o tempo entre a laparostomia e a reconstrução, o tempo operatório e a evolução pós-operatória imediata e tardia incluindo a incidência de hérnias incisionais. RESULTADOS: A idade média dos pacientes foi de 41 anos. As indicações da laparostomia foram; peritonite em oito pacientes, trauma abdominal em outros oito e pancreatite necrotizante em um. O tempo médio até a reconstrução abdominal foi de 14 meses. O tempo médio do procedimento cirúrgico foi de 130 minutos. O período médio de internação hospitalar foi de 2,6 dias para os 15 pacientes sem complicações pós-operatórias. Não houveram óbitos ou ocorrência de síndrome de compartimento abdominal relacionados à técnica. A média do período de acompanhamento pós-operatório é de 24 meses e até o momento não há ocorrência de hérnia incisional em todo o grupo. CONCLUSÕES: A técnica aqui proposta é de fácil execução e reprodutibilidade, torna desnecessária a manipulação da cavidade abdominal com conseqüente diminuição do risco de lesão de vísceras abdominais e proporciona o fechamento definitivo da laparostomia sem tensão. Esta técnica não acarretou síndrome de compartimento abdominal e nenhum paciente desenvolveu hérnia incisional até o momento.

Temporary abdominal closure followed by definitive abdominal wall reconstruction of the open abdomen

BACKGROUND

Inability to close the abdominal wall after laparotomy for trauma may occur as a result of visceral edema, retroperitoneal hematoma, use of packing, and traumatic loss of tissue. Often life-saving, decompressive laparotomy and temporary abdominal closure require later restoration of anatomic continuity of the abdominal wall.

METHODS

The trauma registry, open abdomen database, and patient medical records at a level 1 university-based trauma center were reviewed from January 1988 to December 2001.

RESULTS

During the study period, more than 15,000 trauma patients were admitted, with 88 patients (0.6%) requiring temporary abdominal closure (TAC). Patients ages ranged from 12 to 75 years with a mean injury severity score (ISS) of 28 (range 5 to 54). Forty-five patients (51%) suffered penetrating injuries, and 43 (49%) were victims of blunt trauma. Indications for TAC included visceral edema in 61 patients (70%), abdominal compartment syndrome in 10 patients (11%), traumatic tissue loss in 9 patients (10%), and wound sepsis and fascial necrosis in 8 patients (9%). Fifty-six patients (64%) underwent TAC at admission laparotomy, whereas 32 patients (36%) required TAC at reexploration. Seventy-one patients (81%) survived and 17 (19%) died. Of the survivors, 24 patients (34%) underwent same-admission direct fascial closure, and 47 patients (66%) required visceral skin grafting and readmission closure. Reconstructive procedures in the patients requiring skin graft excision included direct fascial repair (20 patients, 44%), components separation closure with or without subfascial tissue expansion (18 patients, 40%), pedicled or free-tissue flaps (4 patients, 8%), and mesh repair (4 patients, 8%). One patient refused closure. The mean follow-up was 48 months (range 6 to 144), with an overall recurrence rate of 15% (range 10% to 50%), highest in the mesh repair group.

CONCLUSIONS

Silicone sheeting TAC provides a safe and reliable temporary abdominal closure allowing for later definitive reconstruction. Direct fascial repair or components separation closure with or without tissue expansion can be utilized in the majority of patients for definitive reconstruction with low recurrence rate.

Repair of Giant Abdominal Hernias: Does the Type of Prosthesis Matter?

Closure of the abdominal wall after trauma or major surgery may be difficult due to visceral edema or fascial weakness; thus, the risk of developing a ventral hernia (VH) is high. Commonly, these hernias are repaired using a prosthetic mesh. Complications following mesh repair can develop. We hypothesize that the type of prosthetic material affects outcome. This is a retrospective chart review of patients admitted from 1996 to 2002 undergoing VH (≥20 x 10 cm) repair with prosthetic mesh. Data collected included age, sex, and race. Patients were stratified by prosthetic material as follows: Gore-Tex (GR), Marlex + Gore-Tex (MG), Marlex (MR), and Marlex + Vicryl (MV). For the purpose of clinical analysis, the groups were collapsed into subgroups: Gore-Tex exposure (GT) or non–Gore-Tex exposure (NG). Outcome measures were hernia recurrence (HR), wound infection (WI), and fistula formation (FF). Statistical analysis utilized χ2 test and Fisher's exact test. There were 55 VH repairs in 37 patients. The mean age was 43.9 (±16.3), males outnumbered females 22 (59.5%) to 15 (40.5%). The majority of the patients were Caucasian (29; 78.4%). There were 30 trauma patients (81.1%), and 7 general surgery patients (18.9%). The HR for the study ( n = 55) was 20 (36.4%), the WI was 17 (30.9%), and the FF was 3 (5.5%). GR group (6; 66.7%) had a significant higher wound IF rate than MR group (8; 26.7%) (Chi P = 0.02, Fisher P = 0.047). All other group comparisons (HR, WI, and FF) were N.S. The Gore-Tex versus non–Gore-Tex subgroup comparison results were as follows: GT ( n = 18) had a WI 8 (44.4%), HR 6 (33.3%), and FF 0 (0%). NG ( n = 37) had a WI 9 (24.3%), HR 14 (37.8%), and a FF 3 (8.1%). There was a trend toward a higher wound infection in the GT versus NG, but it did not reach statistical significance. We conclude that 1) the wound infection rate was higher in the Gore-Tex versus the Marlex group (Chi P = 0.02, Fisher P = 0.047). Wound infection in the presence of Gore-Tex usually mandates the removal of the mesh resulting in a hernia recurrence. 2) There was a trend toward a higher wound infection in the GT (44.4%) versus NG (24.3%), but it did not reach statistical significance.

The use of a subfascial vicryl mesh buttress to aid in the closure of massive ventral hernias following damage-control laparotomy

Damage control laparotomy for life-threatening abdominal conditions has gained wide acceptance in the management of exsanguinating trauma patients as well as septic patients with acute abdomen. Survivors considered too ill to undergo definitive abdominal wall closure are temporized, often with skin grafting on granulated viscera. These maneuvers compromise the integrity of the anterior abdominal wall and result in a subset of patients with loss of abdominal domain and massive, debilitating ventral hernias. A retrospective review was conducted of 21 such patients (16 men, five women) who underwent elective abdominal wall reconstruction at the Hospital of the University of Pennsylvania between November of 1998 and October of 2000. The purpose of this study was to report the authors' experience with these complex abdominal wall reconstructions. A double-layer, subfascial Vicryl mesh buttress was used in all repairs to aid in reestablishing abdominal wall integrity. The mean hernia size was 813 cm2 (range, 75 to 1836 cm2), and the average interval to definitive repair was 24.4 months (range, 3 weeks to 11 years). Mean follow-up was 13.5 months (range, 1 month to 40 months). Twenty patients (95 percent) had successful ventral hernia repair. Four patients with massive hernias (924 to 1836 cm2) required submuscular Marlex mesh implantation. Two patients (10 percent) developed abdominal compartment syndrome that required surgical decompression. One patient (5 percent) developed an incisional hernia at a prior colostomy site. Four patients (19 percent) had superficial skin dehiscence that healed secondarily with daily wound care. There were no mesh infections. In most cases, successful single-stage repair of large ventral hernias following damage control laparotomy can be achieved using a subfascial Vicryl mesh buttress in combination with other established reconstructive techniques. Massive defects exceeding 900 cm2 typically require permanent mesh implantation to achieve fascial closure and to minimize the risk of postoperative abdominal compartment syndrome and recurrent herniation. This technique represents an improved solution to a complicated problem and optimizes the aesthetic and functional outcome for these debilitated patients.

Abdominoplasty repair for abdominal wall hernias

The objectives of abdominal hernial repair are to reconstruct the structural integrity of the abdominal wall while minimizing morbidity. Current techniques include primary closure, staged repair, and the use of prosthetic materials. Techniques for abdominoplasty include the use of the transverse lower abdominal incision and the resection of excess skin. By incorporating these aspects into hernial repairs, the procedures are made safer and the results are improved. The medical records were reviewed of 123 consecutive patients who underwent hernial repair. Seventy-six of these patients underwent a total of 82 herniorrhaphies using an abdominoplasty approach. This included using a transverse lower abdominal incision with or without extending it into an inverted-T incision. The hernial defect was then identified and isolated. Repair was obtained with primary fascial closure and plication, primary fascial approximation and reinforcement with absorbable Vicryl mesh, or placement of permanent mesh with or without fascial approximation. Overall, 8 of 82 hernias recurred. Most complications were minor and could be managed with local wound care only. Major complications included one enterocutaneous fistula, one occurrence of skin flap necrosis requiring operative debridement and skin grafting, and one delayed permanent mesh extrusion 2 years after repair. The abdominoplasty approach isolates the incision from the hernial defect and repair. This technique is safe with a low risk of complications and a low rate of recurrence. It is particularly helpful in obese patients, in patients with multiple hernias, and in those patients with recurrent hernias.

Risks associated with "components separation" for closure of complex abdominal wall defects

The reconstruction of complex abdominal wall defects can often pose a significant challenge to surgeons and their patients. Complex ventral hernias may result from large tumor resections, trauma from gunshot wounds, or infections following routine abdominal surgery. "Components separation" of the abdominal musculature uses advancement of local autologous tissue, when available, to close large ventral wall defects. The authors report on a retrospective chart review of 30 patients who underwent components separation for the closure of complex abdominal defects. The study group was 50 percent female, with a mean age of 45 years, body mass index of 33.2 kg/m2, and abdominal defect size of 240 cm2. On average, 20 percent of patients had preoperative wound infections, 30 percent had intraoperative bowel enterotomies, and 33 percent required prosthetic mesh for closure. Total surgery time averaged 4.8 hours, with a mean postoperative stay of 12.5 days and follow-up of 9.5 months. The recurrence rate was 10 percent; postoperative complications included midline ischemia, infection, and dehiscence occurring at rates of 20, 40, and 43 percent, respectively. This study provides a comprehensive review of the risks and complications associated with the treatment of complex ventral hernias and those associated with abdominal "components separation."

Skin only or silo closure in the critically ill patient with an open abdomen

BACKGROUND

The morbidity and mortality of various open abdominal techniques remains unclear.

METHODS

A retrospective review was made of all trauma or general surgery patients who underwent an open abdominal closure from January 1997 to December 2000, at a large urban acute care hospital. Data are mean +/- SD.

RESULTS

From 1997 to 2000, 181 patients (aged 39.8 +/- 16.5 years) had an open abdomen for abdominal infection, planned reexploration, abdominal compartment syndrome, inability to reapproximate fascia, or as part of a "damage control" procedure. Twenty-three patients went on to develop an abdominal compartment syndrome. Gastrointestinal fistulas occurred in 26 patients, and 9 patients had a dehiscence. The overall mortality was 44.7%. Of the survivors, 52% went on to fascial closure, requiring 1 to 7 additional abdominal operations.

CONCLUSIONS

The morbidity of the open abdomen varies with the particular indication. Gastrointestinal fistulas are the most common acute complication and an abdominal wall hernia, the most common chronic complication.

Antibody neutralization of vascular endothelial growth factor inhibits wound granulation tissue formation

OBJECTIVE

The goal of this work was to test the functional role of vascular endothelial growth factor (VEGF) in promoting the vigorous granulation tissue formation, wound fluid accumulation, and angiogenic responses characteristic of this wound model.

BACKGROUND

Formation of vessel-rich granulation tissue is central to wound repair and is thought to be regulated by locally liberated angiogenic factors. Despite the clinical importance of granulation tissue formation in the early stage of wound healing, surprisingly little is known about the molecular identity of signals leading to granulation tissue invasion of a wound space. Methods. A ventral hernia, surgically created in the abdominal wall of 15 swine, was repaired using silicone sheeting and skin closure. An osmotic minipump, inserted in a remote subcutaneous pocket, delivered saline (n = 5), an irrelevant control antibody (n = 5), or neutralizing anti-VEGF antibody (n = 5) into the wound environment. Serial ultrasonography on Days 2, 4, 7, 9, 11, and 14 was used to determine the dimensions of the subcutaneous granulation tissue and wound fluid compartment. VEGF and transforming growth factor beta1 (TGF-beta1) levels in serial wound fluid samples were quantitated by ELISA. On Day 14, animals were sacrificed and the abdominal wall was harvested for histologic, biochemical, and molecular analyses.

RESULTS

In animals receiving saline or an irrelevant antibody, a nearly linear 4-fold increase in granulation tissue thickness and 7-fold increase in wound fluid volume were measured over the 14-day study interval. In contrast, in animals receiving anti-VEGF neutralizing antibody, Day 14 granulation tissue thickness and wound fluid volume measurements were essentially unchanged from Day 2 values. Moreover, in the anti-VEGF animals, ultrasonography was unable to resolve the "angiogenic zone" typical of both controls, and correspondingly, wound vessel count and vascular surface area estimates derived from image analysis of histological sections were 3-fold lower in the anti-VEGF animals compared with the saline and antibody controls. Finally, VEGF levels in wound fluid detectable by ELISA analysis were strikingly (10-fold) reduced in anti-VEGF animals on Postsurgery Days 7-14. In contrast, TGF-beta1 levels were unaffected by the anti-VEGF treatment.

CONCLUSION

Functional VEGF is a key mediator in wound angiogenesis, fluid accumulation, and granulation tissue formation.

Cloning, expression and immunological reactivity of two mammalian cell entry proteins encoded by the mce1 operon of Mycobacterium tuberculosis

The DNA segments corresponding to two members of the mammalian cell entry operon 1 (mce1) encoding Mce1A and Mce1E proteins were amplified from Mycobacterium tuberculosis genomic DNA by polymerase chain reaction, cloned and subcloned into pGEM-T and pGEX-4T-3 vectors, respectively, and expressed in Escherichia coli as fusion proteins with glutathione-S-transferase (GST) of Schistosoma japonicum as the fusion partner. The recombinant proteins appeared as major cellular proteins in SDS-PAGE gels at the expected molecular mass of 68 kDa and 64 kDa for GST-Mce1A and GST-Mce1E, respectively. The identity of each fusion protein was confirmed by reactivity with anti-GST antibodies in Western immunoblots. The fusion proteins were purified to near homogeneity by affinity chromatography, and purified Mce1A and Mce1E, free of the fusion partner, were recovered following specific proteolytic cleavage of the GST portion by thrombin protease. Purified Mce1E appeared as a single band of 38 kDa, whereas purified Mce1A tended to exist in degraded as well as aggregated forms of different sizes. The fusion proteins, free GST and monomeric Mce1A and Mce1E reacted in Western immunoblots with antibodies in pools of human sera from six to 11 tuberculosis patients. Similar analysis showed the presence of antibodies to GST and Mce1A, in pools of human sera from M. bovis BCG-vaccinated healthy subjects. When pure Mce1E was blotted against individual sera, antibodies in 4/10 sera from tuberculosis patients reacted, whereas no reaction was seen with 10 individual sera from M. bovis BCG-vaccinated healthy subjects. However, when the same sera were tested for reactivity to the purified preparation of Mce1A, 8/10 sera from both tuberculosis patients and M. bovis BCG-vaccinated healthy subjects showed positive reactivity. These findings demonstrate that both Mce1A and Mce1E are expressed and immunogenic during natural infection with M. tuberculosis.

Optimal prosthetic for acute replacement of the abdominal wall

OBJECTIVE

To compare two prostheses for use in acute abdominal wall replacement in the presence and absence of peritonitis.

MATERIALS AND METHODS

Forty male Sprague-Dawley rats underwent full-thickness removal of a 2 x 3 cm portion of their anterior abdominal wall. Twenty rats had intraperitoneal contamination with stool slurry. Ten rats in each group (contaminated and noncontaminated) had a 2 x 3 cm piece of Gore-Tex dual-mesh expanded polytetrafluoroethylene (PTFE) sewn full-thickness to cover the abdominal wall defect. The remaining 10 rats in each group had replacement with a 2 x 3 cm piece of Dexon polyglycolic acid mesh (PGA). The rats were then awakened and returned to their cages. Rats were humanely killed at the end of a 3-week observation period or at the time of fistula formation or evisceration. At necropsy, the density of intraabdominal adhesions was graded on a scale of 0 to 3, and the extent of reepithelialization was noted. Results were analyzed with the Student's t test or Fisher's exact method of chi2 test as indicated.

RESULTS

Nineteen PTFE rats and 10 PGA rats survived the observation period, The PTFE rats had significantly fewer adhesions (0.10+/-0.30 vs. 1.27+/-1.49,p < 0.005) and significantly more reepithelialization of their wounds (78.2+/-23.4% vs. 43.6+/-50.4%,p < 0.05) than the PGA rats. Evisceration and fistula formation occurred more frequently in the PGA group. The mortality in the PTFE rats was significantly less than the PGA rats (5% vs. 50%,p < 0.001.) Notably, the contaminated PGA rats had a significantly higher mortality (90%,p < 0.001) than any of the other subgroups.

CONCLUSION

PTFE is superior to PGA as a replacement prosthesis for acute abdominal wall defects. There are significantly fewer adhesions, improved epithelialization of the wound, and less morbidity and mortality when PTFE is used. This finding is especially true in the presence of intraperitoneal fecal soilage.

Synthetic graft placement in the treatment of fascial dehiscence with necrosis and infection

OBJECTIVE

The objective of this study was to describe the use of synthetic grafts in repairing fascial dehiscence complicated by fascial necrosis and infection after obstetric and gynecologic operations.

STUDY DESIGN

A retrospective review of the operating room records at Hutzel Hospital (Detroit, Mich) was performed to find all cases of fascial dehiscence repaired during a 6-year period between January 1, 1991, and December 31, 1996. Patients with partial or complete disruption of the fascia with evidence of fascial necrosis and infection were included in this study. Demographic information; the initial surgical procedure, including type of incision; suture material; use of synthetic graft and closure technique for repair of dehiscence; postoperative complications, microbiologic results; antibiotic therapy; subsequent operations; length of hospital stay; and late complications were recorded.

RESULTS

During the study period 52 patients underwent repair of fascial dehiscence; 36 of these had concurrent fascial necrosis and infection, including 4 women with necrotizing fasciitis. Eighteen patients were from the obstetric service and 18 were from the benign or cancer gynecology service. Ninety-one bacterial isolates were recovered from the infected wounds. Extensive fascial resection precluded closure without tension in 18 cases and necessitated synthetic graft placement to prevent evisceration. Graft materials included polypropylene (11 cases) and polyglactin (7 cases). Late complications of graft placement included extrusion of the graft in 3 patients and incisional hernia in 1.

CONCLUSIONS

Extensive fascial débridement with resection prevents primary closure of wound dehiscence. Synthetic grafts permit primary closure of large fascial defects and can be used with extensive débridement in the presence of infection.

Normoxic wound fluid contains high levels of vascular endothelial growth factor

OBJECTIVE

To examine the temporal integration of vascular endothelial growth factor (VEGF), which has been shown to be present in wound fluid, with the putatively related processes of wound fluid oxygen content, wound angiogenesis, and granulation tissue formation.

SUMMARY BACKGROUND DATA

During cutaneous wound repair, new tissue formation starts with reepithelialization and is followed by granulation tissue formation, including neutrophil and macrophage accumulation, fibroblast ingrowth, matrix deposition, and angiogenesis. Because angiogenesis and increased vascular permeability are characteristic features of wound healing, VEGF may play an important role in tissue repair.

METHODS

A ventral hernia, surgically created in the abdominal wall of female swine, was repaired using silicone sheeting and skin closure. Over time, a fluid-filled wound compartment formed, bounded by subcutaneous tissue and omentum. Ultrasonography was performed serially to examine the anatomy and dimensions of the subcutaneous tissue and wound compartment. Serial wound fluid samples, obtained by percutaneous aspiration, were analyzed for PO2, PCO2, pH, and growth factor concentrations.

RESULTS

Three independent assays demonstrate that VEGF protein is present at substantially elevated levels in a wound fluid associated with the formation of abdominal granulation tissue. However, the wound fluid is not hypoxic at any time. Serial sampling reveals that transforming growth factor beta-1 protein appears in the wound fluid before VEGF.

CONCLUSIONS

The results suggest that VEGF is a prominent regulator of wound angiogenesis and vessel permeability. A factor other than hypoxia, perhaps the earlier appearance of another growth factor, transforming growth factor beta-1, may positively regulate VEGF appearance in the wound fluid.