Thomas L. Chung

Incisional negative-pressure wound therapy versus conventional dressings following abdominal wall reconstruction: a comparative study.

BackgroundImprovements in surgical techniques have allowed us to achieve primary closure in a high percentage of large abdominal hernia repairs. However, postoperative wound complications remain common. The benefits of negative-pressure wound therapy (NPWT) in the management of open abdominal wounds are well described in the literature. Our study investigates the effects of incisional NPWT after primary closure of the abdominal wall. MethodsA retrospective chart review was performed for the period between September 2008 and May 2011 to analyze the outcomes of patients treated postoperatively with incisional NPWT versus conventional dry gauze dressings. Patient information collected included history of abdominal surgeries, smoking status, and body mass index. Postoperative complications were analyzed using &khgr;2 exact test and logistic regression analysis. ResultsFifty-six patients were included in this study; of them, 23 were treated with incisional NPWT, whereas 33 received conventional dressings. The rates of overall wound complications in groups I and II were 22% and 63.6%, respectively (P = 0.020). The rates of skin dehiscence were 9% and 39%, respectively (P = 0.014). Both outcomes achieved statistical significance. Rates of infection, skin and fat necrosis, seroma, and hernia recurrence were 4%, 9%, 0%, and 4% for group I and 6%, 18%, 12%, 9% for group II, respectively. ConclusionsThis study suggests that incisional NPWT following abdominal wall reconstruction significantly improves rates of wound complication and skin dehiscence when compared with conventional dressings. Prospective, randomized, controlled studies are needed to further characterize the potential benefits of this therapy on wound healing after abdominal wall reconstruction.

Acellular Dermal Matrix Compared with Synthetic Implant Material for Repair of Ventral Hernia in the Setting of Peri-Operative Staphylococcus aureus Implant Contamination: A Rabbit Model

BACKGROUND Implant infection is a common clinical complication of abdominal hernia repair. Our objectives were to determine if acellular dermal matrix (ADM) grafts resisted Staphylococcus aureus infection better (as measured by ability to reduce or clear bacterial counts) than synthetic (polytetrafluoroethylene [PTFE]) mesh when used in abdominal wall reconstruction, and to determine whether vascularization of the implant occurred. We hypothesized that the ability of the ADM grafts to vascularize and allow cellular ingrowth would allow the immune system to clear the infection better in these animals. METHODS In New Zealand White rabbits (average weight, 3.0 kg), a full-thickness 3 x 3 cm(2) abdominal defect was created, then repaired with an interpositional implant (ADM, n = 62; PTFE, n = 57). Before skin closure, the epidermal surface of each implant was inoculated with 1 mL of S. aureus at various concentrations (10(4) colony-forming units [CFU]/mL, n = 82; 10(6) CFU/mL, n = 27; 10(9) CFU/mL, n = 10), and the rabbits were harvested at either day 7 or day 21. RESULTS At day 7, ADM grafts inoculated with 10(4) CFU had lower counts or no bacteria (p = 0.006), fewer adhesions (p = 0.005), and fewer abscesses (p = 0.008) than PTFE grafts. By day 21, more ADM (n = 12) than PTFE (n = 0) grafts were free of bacteria (p = 0.002). Fewer rabbits with ADM grafts formed abscesses (13 vs. 19; p = 0.03). When evaluating the 7- and 21-day 10(4) CFU groups combined, a total of 15 rabbits with ADM cleared the bacteria completely vs. none of those with PTFE grafts (p < 0.001). There was no significant difference in bacterial counts or wound complications at days 7 or 21 between PTFE and ADM implants when inoculated with 10(6) CFU. All rabbits inoculated with 10(9) CFU died of sepsis within 48 h. Herniation did not occur in any of the animals. CONCLUSIONS Our study demonstrates that ADM resists surgical site infection caused by S. aureus in an animal model without compromising the ventral hernia repair. This ability of ADM grafts to perform well in the setting of infection is most likely attributable to their capacity to vascularize and aid clearance of bacteria.

Lessons from operation Iraqi freedom: successful subacute reconstruction of complex lower extremity battle injuries.

Background: War wounds associated with Operation Iraqi Freedom have created a unique reconstructive challenge. The objective of this study was to report and analyze the timing and success rates of lower extremity reconstruction associated with devastating war wounds. Methods: A retrospective review was conducted of injured personnel requiring extremity flap reconstruction at the National Naval Medical Center over a 30-month period. Collected data included mechanism of injury, time from initial injury to closure, number of prereconstruction wound washouts, types of flap, flap failures, associated injuries, and wound culture characteristics. Results: From September of 2004 to February of 2007, 46 (36 pedicled and 10 free flaps) lower extremity flap reconstructions (10 fasciocutaneous, 34 musculocutaneous, and two adipofascial) were performed on 43 patients. Patient age ranged from 19 to 37 years. Time to reconstruction ranged from 7 to 82 days (average, 21 days). Seventy-six percent of all injuries were associated with an improvised explosive device blast. Mean number of prereconstructive washouts was five (range, two to 13). Fifty percent of all wounds cultured at admission revealed positive results, of which 57 percent were associated with Acinetobacter species. Total flap loss occurred in one flap and partial flap loss occurred in two flaps. Conclusion: Despite reconstruction in the subacute period, the high rate of antimicrobial colonization before wound closure, and the devastating nature of improvised explosive device blast injuries, early analysis of the National Naval Medical Center war extremity reconstruction cohort demonstrates low total and partial flap loss rates and acceptable infection rates.

Lessons from the modern battlefield: Successful upper extremity injury reconstruction in the subacute period

BACKGROUND Reconstructive techniques and protocols for limb salvage of upper extremity battlefield injuries remains poorly defined. Our study describes the types of flaps, the timing of reconstruction, and success rates of war upper extremity reconstruction during a 30-month period using the Bethesda limb salvage protocol. METHODS Soldiers with significant upper extremity injuries with complex open fractures from Operation Iraqi Freedom and Operation Enduring Freedom-Afghanistan who underwent tissue transfer flaps were reviewed (n = 26, free flaps n = 6). Data analysis included mechanism of injury, associated injuries, types of flap, postoperative complications, wound infection rates, and outcome data. RESULTS The cause of injury consisted of improvised explosive device (61%), rocket-propelled grenades (15%), motor vehicle crash (8%), land mine (8%), and gunshot wound (4%). Mean age was 25 years. Mean number of prereconstructive washouts was six (range, 3-22). Forty-six percent of wounds were culture positive at admission (75% were Acinetobacter species). All patients had other coexisting extremity, trunk or facial injuries. Average time to flap reconstruction was 31 days (range, 9-161). In 66% of the cases, a fasciocutaneous flap was used, and in the remaining cases, muscle (19%) and adipofascial (15%) flaps were performed. Flap success rate was 96%, with one flap loss because of venous congestion (managed with limb shortening). Infection rate was 8%. Complete coverage was achieved in all upper extremity wounds and early occupational therapy resulted in improved return to function. CONCLUSIONS Despite massive bone and soft tissue defects, high preoperative wound colonization, and delays in definitive reconstruction, devastating war wounds can be successfully reconstructed in the subacute period with low flap failure, infection, and amputation rates.

Comparison of acellular dermal matrix and synthetic mesh for lateral chest wall reconstruction in a rabbit model.

Background: Synthetic mesh is used for chest wall reconstruction, but infection or exposure can occur and necessitate removal. Human acellular dermal matrix (AlloDerm) has been used to reconstruct musculofascial defects in the trunk with low infection and herniation rates. AlloDerm may have advantages over synthetic mesh for chest wall reconstruction. This study compared outcomes and repair strengths of AlloDerm to expanded polytetrafluoroethylene mesh used for repair of rib cage defects. Methods: A 3 × 3-cm, full-thickness, lateral rib cage defect was created in each rabbit and repaired with expanded polytetrafluoroethylene (n = 8) or acellular dermal matrix (n = 9). At 4 weeks, the animals were euthanized and evaluated for lung herniation/dehiscence, strength of adhesions between the implant and intrapleural structures, and breaking strength of the implant materials and the implant-fascia interface. Tissue sections were analyzed with histologic and immunohistochemical staining to evaluate cellular infiltration and vascularization. Results: No herniation or dehiscence occurred with either material. The incidence and strength of adhesions was similar between materials. The mean breaking strength of the AlloDerm-fascia interface (14.5 ± 8.9 N) was greater than the expanded polytetrafluoroethylene–fascia interface (8.7 ± 4.4 N; p = 0.027) and similar to the rib-intercostal-rib interface of the contralateral native chest wall (14.0 ± 5.6 N). The AlloDerm grafts became infiltrated with cells and vascularized after implantation. Conclusions: AlloDerm used for chest wall reconstruction results in greater implant-defect interface strength than expanded polytetrafluoroethylene. The ability of AlloDerm to become vascularized and remodeled by autologous cells and to resist infection may be advantageous for chest wall reconstruction.

Prevention of microsurgical anastomotic thrombosis using aspirin, heparin, and the glycoprotein IIb/IIIa inhibitor tirofiban

Background: Recent clinical trials involving patients with acute coronary syndromes have demonstrated significant reduction in the progression of coronary artery thrombosis using a regimen of aspirin, heparin, and the glycoprotein IIb/IIIa inhibitor tirofiban. Acute coronary syndromes and free tissue transfer are similar pathophysiologically in that they both involve endothelial injury, thrombosis, and ischemia. In this study, the authors investigate tirofiban, combined with aspirin and heparin, for the prevention of microsurgical anastomotic thrombosis in a thrombogenic rat model. Methods: Using a randomized, controlled, double-blind experimental design, 80 thrombogenic anastomoses were performed on rat femoral arteries (n = 40) and veins (n = 40). Preoperatively, each rat received one of four treatment regimens: aspirin and heparin (regimen 1), aspirin and heparin plus tirofiban (regimen 2), tirofiban alone (regimen 3), or isotonic saline (control) (regimen 4). Vessels were assessed for patency at 5, 15, 30, and 120 minutes after reperfusion and then harvested for microscopic analysis. Results: At 120 minutes after reperfusion, regimen 1 had an arterial and venous patency rate of 80 percent and 70 percent, respectively, whereas the vessel patency rate for regimen 2 was 100 percent. The difference between regimens 1 and 2 was not statistically significant. Regimens 3 and 4 had vessel patency rates of 40 percent or less. The aspirin/heparin and aspirin/heparin/tirofiban groups both demonstrated significantly improved vessel patency and significantly less thrombotic occlusion compared with controls. Conclusions: Combination therapy with aspirin, heparin, and tirofiban significantly increases arterial and venous patency and decreases anastomotic thrombus formation in thrombogenic anastomoses in rats. The role of glycoprotein IIb/IIIa inhibitors in microsurgery warrants further investigation.

A novel reconstructive technique following central lumpectomy.

Breast conservation therapy is a wellestablished treatment method for subareolar breast cancers, provided that the nipple-areola complex is completely removed, adequate surgical margins are obtained following tumor resection, and adjuvant radiation therapy is received. After resection of the central breast and nipple-areola complex, the remaining surgical defect is commonly closed primarily. However, this frequently results in an unattractive deformity, especially with larger subareolar tumors. We describe an immediate reconstructive technique after central lumpectomy and nipple-areola complex resection that demonstrates excellent cosmesis following radiation therapy.

Improving long-term projection in nipple reconstruction using human acellular dermal matrix: An animal model

Reconstructed nipples rapidly lose projection. We describe the use of human acellular dermal matrix (ADM) to improve long-term projection of nipple flaps. Athymic rats were randomized to 3 groups; each received 2 nipples: bell flap (control, n = 16 nipples), bell flap with a cylinder of implanted ADM (n = 24), or bell flap with intraflap injection of micronized ADM (MADM) (n = 10). Seven of 24 ADM nipples extruded (30%). By 12 weeks, the control nipples maintained 44% of initial projection compared with 70% for ADM nipples (P = 0.000025). The MADM nipples maintained 49% of initial projection after 12 weeks (P = 0.55 compared with control). No MADM nipples extruded. ADM grafts maintain long-term projection better than local tissue flaps alone. We hypothesize that MADM may limit extrusion and allow for serial injection of nipples. Based on the promising results of this study, clinical trials are warranted using human ADM and/or human MADM for nipple reconstruction.

Breast-feeding, self-exam, and exercise practices before and after reduction mammoplasty

The current indications for reduction mammoplasty include the relief of painful physical symptoms of macromastia. Numerous studies have demonstrated not only improvement in physical symptoms following reduction mammoplasty, but postoperative psychological benefits as well, including increased ability to participate in physical activity as a result of pain relief and decreased breast mass. Reduction mammoplasty may have additional effects on the patients ability to breast-feed and perform breast self-exam. The present study is a retrospective study of the effects of reduction mammoplasty on breast-feeding, breast self-exam, physical symptoms, and physical activity. One-hundred and forty-one patients who underwent reduction mammoplasty at our institution between the years 1996–2005 agreed to participate in the study. Each was asked a series of questions in order to assess changes in symptoms and behaviors including breast-feeding and breast self-exam practices before and after the surgery. Patients were also asked questions regarding their pain symptoms and physical activity profiles. Ninety-seven percent of the participants claimed to have back, neck, and/or shoulder pain that was either significantly improved or completely resolved. Moreover, 100% of patients report that physical activity such as exercise was easier following reduction mammoplasty. Ninety-three percent of participants reported that performing breast self-exam following surgery was either the same (68%) or easier (25%) as a result of having less breast tissue. Eighty-nine percent of participants had no children following surgery, therefore effects on breast-feeding practices following reduction mammoplasty were not statistically significant. However, we suggest that when patients are seen in consultation or in the perioperative period, there is an opportunity to teach patients about the benefits of breast-feeding, and to assure patients that a pedicle flap reduction will likely allow breastfeeding. This is also a chance for physicians to teach patients how to perform breast self-examination and explain the importance of early breast mass detection.

Efficacy of a percutaneous A1 pulley release technique with identification of anatomic differences between genders

Background:This cadaver study investigates the efficacy and safety of the Biomet knife and technique for percutaneous A1 pulley release. We also evaluate the anatomic relationship between specific palmar surface landmarks and relevant underlying structures and identify differences between genders. Methods:Eighty percutaneous A1 pulley releases, excluding the thumb, were performed on 20 fresh human cadaver hands (10 male, 10 female). Results:Complete release was obtained in 60 of 80 fingers. Success rates for each surgeon improved markedly as the study progressed. There were no significant differences between males and females regarding the distance between a standardized incision site and the proximal edge of the A1 pulley. Conclusions:A learning curve exists for percutaneous A1 pulley release using the Biomet knife and technique. The extended distal palmar crease is a reasonable incision site for percutaneous release of the index, middle, and ring A1 pulleys in both men and women as the A1 pulley begins just distal to this surface landmark.