Effect of suture material on tensile strength and complication rate in abdominal fascial defects repaired with acellular dermal matrix.

BACKGROUND: Repair of ventral hernias represents a challenging problem for surgeons. AlloDerm (LifeCell, Branchburg, NJ, USA), an acellular dermal matrix (ADM) product derived from cadaveric human skin, has gained in popularity in the management of abdominal hernias because of its ability to support neovascularization and therefore resist infection. Surgeons have traditionally used nonabsorbable suture when using ADM in this setting, perhaps because of concerns regarding wound strength. This study was undertaken to examine the influence of suture material on wound breaking strength and complication rates in abdominal wall defects closed with ADM. METHODS: Full-thickness abdominal defects were created in athymic rats and immediately repaired with an ADM interposition graft using either interrupted Prolene or Maxon suture. Complications were recorded over time and the animals were sacrificed at 1 month intervals. The abdominal repair complex was harvested and wound strength was measured using a tensiometer. RESULTS: There were no hernias in any of the groups. There were also no cases of major adhesions to the AlloDerm. Two rats in the Prolene group developed a stitch extrusion through the ventral skin. Wound breaking strength increased significantly from the second to third month after surgery in both suture groups (p=0.0000, LSD test). The breaking strength of the abdominal fascia-ADM complex increased over the course of the experiment in both test groups, but no significant difference was found between the groups at any time point (p=0.3157). At 3 months, the breaking strength of the Prolene group and Maxon group was nearly identical (27.1 N +/- SD 7.4 and 29.7 N +/- SD 9.6, respectively). CONCLUSIONS: We were unable to identify a significant difference in breaking strength at the interface between ADM and normal, native fascia when using permanent versus resorbable sutures.

A technique for determining E rosette levels by cytofluorographic analysis.

A method is described for determining the percentage of rosettes formed by sheep erythrocytes and human peripheral lymphocytes (ER) using cytofluorographic analysis (CFGA). The technique utilizes acridine orange dye for differentially staining nucleus and cytoplasm of the lymphocytes to distinguish them from erythrocytes, and glutaraldehyde for fixation of the rosettes. This technique was compared with light microscope counting (LMC) or ER. CFGA gave similar results with better reproducibility than LMC, entailed less time for counting, and markedly reduced operator fatigue.

Experimental repair of ventricular septal defects using autologous right ventricular muscle flaps: preliminary report.

Survival after repair of postinfarction ventricular septal defects remains poor, often due to extensive loss of contractile muscle in the septum or left ventricle. We evaluated whether a contractile flap of right ventricular muscle could be used to repair a similar ventricular septal defect to augment left ventricular performance in 7 fully instrumented mongrel dogs (weight, 23 to 28 kg). By using hypothermic bypass and cold fibrillatory arrest, a trapezoidal right ventricle flap was fashioned from the free wall of the mid to lower right ventricle, basing its widest portion anteriorly on the septum and left ventricle. A large, 2-cm-diameter core of septum was excised beneath this flap to simulate a postinfarct ventricular septal defect. The right ventricular flap was then invaginated through the defect and sewn to the left ventricular side of the septum with pledgeted sutures taken full thickness through the flap and septum in a "vest-over-pants" fashion. Contraction of the right ventricular flap was confirmed visually and by postbypass multiple gated acquisition scans. The right ventricular defect was closed with fascia lata. All dogs were weaned from bypass without inotropes. Precardiac and postcardiac outputs of 2.5 +/- 0.5 versus 2.3 +/- 0.4 L/min and left ventricular end-diastolic pressures of 4 +/- 2 versus 4 +/- 3 mm Hg were identical. No shunts were detected by oxygen saturation. Autopsies confirmed the integrity of the repair. We conclude that septal defects can be repaired by using contractile right ventricular muscle, thus preserving left ventricular function. This technique offers promise for repair of postinfarction ventricular septal defects by using autologous, already conditioned to contract, cardiac muscle, but its application in humans must await long-term testing.

Ventral hernia repair using allogenic acellular dermal matrix in a swine model.

BACKGROUND: This study was designed to assess the long-term efficacy of allogenic acellular dermal matrix (ADM) used as an interpositional graft for ventral hernia repair in a swine model. METHODS: We created 12x4-cm full-thickness abdominal wall defects in 22 Yucatan miniature pigs. The defect was repaired with either two 6x4-cm pieces of AlloDerm (acellular dermal matrix processed from pig skin in order to avoid a xenogenic response, LifeCell Corporation, Branchburg, NJ USA) (n = 12), or expanded polytetrafluoroethylene mesh (ePTFE) (Gore-Tex, W.L. Gore & Associates, Inc., Newark, DE USA) (n = 10). In six pigs, a separate 3-cm fascial incision was made, which was then suture repaired as a control for tensiometry testing. The surgical sites were evaluated at either 3 months or 9 months for the presence of a hernia, stretching of the implant, adhesions, vascularity, and biomechanical strength. RESULTS: Two hernias occurred in both the ADM and the ePTFE groups. There was minimal stretching of the implants and minimal adhesions in both groups. Fluorescein testing and histology indicated vascular ingrowth into the ADM. There was no statistical difference between the mean breaking strengths of the ADM-fascial interface (106.5 N +/- SD 40.1), the interface between two pieces of ADM (149.1 N +/- SD 76.7), and the primary fascial repair (108.1 N +/- SD 20.9) at 9 months. The ADM-fascial interface had a significantly higher breaking strength than that of the ePTFE-fascia interface (66.1 N +/- SD 30.1) (P = 0.017, t-test, P = 0.043 Wilcoxon rank sum test). CONCLUSIONS: In this study, we were unable to demonstrate a difference between ADM and ePTFE in their ability to repair ventral hernias at 9 months in a swine model. The ADM additionally supports vascular ingrowth and exhibits increased breaking strength at the fascia-implant interface.

Soft-tissue masses of the temporal fossa.

An unusual problem, a soft-tissue mass of the left temporal fossa, is described. Differential diagnoses and pertinent studies for identifying the mass are reviewed. Our patient had a temporalis fascia defect with herniation of the temporal muscle causing his mass and associated symptoms. Surgical exploration, necessary for diagnosis, afforded us the opportunity for definitive treatment.

An experimental model to determine the effects of adjuvant therapy on the incidence of postoperative wound infection: II. Evaluating preoperative chemotherapy.

A study was performed in 110 rats to investigate the effect of an LD50 dose of MTX, rescued with leucovorin treatment in 24 hours, on the ability of surgical wounds to tolerate bacterial contamination. The results of this study would indicate that the optimal time to ensure normal wound healing would be an interval of 10 to 14 days following the administration of large doses of this drug. This information would suggest that the use of methotrexate as a preoperative adjuvant, and radiation therapy following the surgical removal of the tumor, might be a reasonable approach to the adjuvant treatment of head and neck cancer without increasing the risk of wound infections.

A comparison of obsidian and surgical steel scalpel wound healing in rats.

There are several anecdotal clinical articles claiming wound healing and scar superiority using obsidian (volcanic glass) scalpels. In order to determine if skin incisions made with obsidian were superior to those made with standard surgical steel, wound tensile strength, scar width, and histology were assessed in 40 adult male Sprague-Dawley rats. Each rat received two parallel 8-cm dorsal skin incisions, one with an obsidian scalpel and the other with a surgical steel scalpel (no. 15 blade). Data were analyzed by ANOVA. Tensile strength of the two wound types was not different at 7, 14, 21, and 42 days. Scar width, however, was significantly less in the obsidian wounds at 7, 10, and 14 days (p < 0.005). At 21 days, scar width was not different in the two groups. At 42 days, all wounds were barely detectable, thus precluding scar width analysis. A blinded histologic review suggested that obsidian wounds contained fewer inflammatory cells and less granulation tissue at 7 days.

Update on the anatomy of the pulley system in the chicken foot long digit.

The pulley system in the flexor sheath of the long toe of the white leghorn chicken foot was studied. Histologic sections of the pulleys were prepared, and the mechanics of flexion of the long toe was analyzed. An annular flexor pulley that attached to the third phalanx was identified. This pulley, which has not been described previously, was found to be essential for proper flexion of the third interphalangeal joint.

Efficacy of operative cure in pressure sore patients.

The advent of air flotation-type beds and purified growth factors that may accelerate open wound contraction, coupled with very high recurrence rates and decreasing health resources, suggests that surgical reconstruction of pressure sores may not be indicated in all patients. In an effort to define which patients might benefit from operation, we reviewed the data from 40 consecutive patients with 68 pressure sores operated on under the direction of a single surgeon between 1981 and 1989. Patients were categorized on the basis of the presence or absence of paraplegia and its etiology. Sixty-six operations were performed, 55 muscle or fasciocutaneous flaps and 11 cutaneous flaps. There was a 36 percent operative complication rate, with no operative mortalities. Follow-up ranged from 1 to 71 months, with a mean of 21 months. Despite an 80% healed rate at the time of discharge, 61% of sores and 69% of patients had recurrent ulceration within a mean of 9.3 months. Analysis of these data indicates that surgical reconstruction of pressure sores does not appear to be efficacious in young posttraumatic paraplegics or cerebrally compromised elderly patients. Further review of the data failed to identify those patients likely to remain healed after operative repair of their pressure sores.

Advantages of autologous fascia versus synthetic patch abdominal reconstruction in experimental animal defects.

Although prosthetic patches (i.e., expanded polytetrafluoroethylene) are commonly used to repair abdominal fascial defects, autologous tissue is preferred in the presence of wound contamination. This study was undertaken to discover (1) whether fascial grafts are revascularized and incorporated as living tissue, and (2) whether fascial grafts are more resistant to bacterial contamination than prosthetic patches. In the first experiment, 18 New Zealand White rabbits underwent full-thickness resection of the central abdominal wall preserving only panniculus carnosus and skin. Six control animals had only skin repaired, and all developed large ventral hernias. Twelve animals had the defect repaired with thoracodorsal fascia patches. At 3- and 6-week intervals, no hernias were present and all patches were incorporated with minimal contraction. Fluorescein angiography verified revascularization from the surrounding abdominal wall. Next, 36 rabbits underwent similar resection followed by repair with either autologous fascia (n=18) or expanded polytetrafluoroethylene (n=17). Six rabbits of each repair group were inoculated with 10(4) Staphylococcus aureus and twelve rabbits with each repair were inoculated with 10(9) S. aureus. All rabbits receiving 10(4) S. aureus were infection-free survivors. Seven of the twelve expanded polytetrafluoroethylene-repaired animals receiving 10(9) S. aureus developed necrotizing wound infections and died. Only 2 of 12 rabbits with autologous fascia repairs died from wound sepsis and 1 died of diarrhea with a healed wound. Differences in wound infection rates achieved statistical significance, whereas survival differences approached significance (Fisher's exact test), suggesting that revascularized fascial grafts may be more resistant to bacterial contamination than expanded polytetrafluoroethylene patches at this concentration (10(9) S. aureus).

Improved reliability in tumor diagnosis by fine needle aspiration.

A simple but useful modification of sample preparation of fine needle aspirates of soft tissue masses is presented, in conjunction with its assessment by a controlled study. The modification, employing routine histologic techniques, reduces the requirement for cytopathologic expertise. The potential utility of fine needle aspiration is thereby significantly expanded. In addition, this modification allows the pathologist to use special tissue strains or electron microscopy as options, when necessary, to enhance diagnostic accuracy.

Prevention of adriamycin-induced full-thickness skin loss using hyaluronidase infiltration.

Full-thickness skin ulceration after extravasation of the commonly used vesicant chemotherapeutic agent doxorubicin hydrochloride (Adriamycin) is a significant source of morbidity in cancer patients. Controversy exists regarding the appropriate management of this extravasation injury. Current therapy includes local hypothermia, local clysis with hyaluronidase, and surgical excision of the involved tissue. Experimental data supporting local clysis with hyaluronidase are limited despite its current use clinically. The purpose of this study was to determine the efficacy of local infiltration with heparin sodium, hyaluronidase, and saline in the prevention of extravasation ulcers in a rat model. One hundred fifty male Sprague-Dawley rats (Upjohn, Milan, Italy) weighing 240 to 260 g, anesthetized with sodium pentobarbital, were used in this study. One hundred thirty rats received a 0.3-ml subcutaneous flank injection of doxorubicin (1.5 mg/ml) followed 15 minutes later by local infiltration with saline (n = 10), 25 to 100 units of heparin (n = 30), or 2.5 to 10.0 units of hyaluronidase (n = 90). Control animals received either subcutaneous doxorubicin (n = 10) or subcutaneous saline alone (n = 10). Volumes of the infiltration solution were less than 1 ml in all groups. All animals were sacrificed at 4 weeks; presence and size of ulcers at the injection site were quantified. Statistical analysis was performed using the two-sided Fisher's exact test and Student's t test. Control rats injected with saline alone did not develop ulceration in any case. All rats injected with doxorubicin alone developed ulcers with an average size of 33 mm2. Heparin infiltration decreased ulcer rate by 20 to 40 percent and decreased ulcer size by up to 67 percent. Local infiltration with hyaluronidase decreased ulcer rate by 50 to 60 percent (p < 0.05, two-sided Fisher's exact test) and decreased ulcer size by up to 50 percent ( p < 0.05, Student's t test). In this rat extravasation injury model, local infiltration with saline, heparin, or hyaluronidase decreased ulcer size after doxorubicin extravasation. This effect may be secondary to dilution of the extravasant. Additionally, local infiltration with hyaluronidase decreased ulcer rate by at least 50 percent. The mechanism of this phenomenon presumably relates to the ability of hyaluronidase to temporarily decrease the viscosity of the hyaluronic acid component of ground substance, thus allowing greater diffusion of doxorubicin into the surrounding tissue and therefore decreasing its local concentration.

Restoring abdominal wall integrity in contaminated tissue-deficient wounds using autologous fascia grafts.

Necrotizing abdominal wall infections, enteric fistulae, or exposed prosthetic material after ventral hernia repair often results in a loss of abdominal wall integrity. Further surgical reconstruction with prosthetic material is usually contraindicated in the contaminated wound because of the high infection rate necessitating prosthetic removal and further abdominal wall debridement. Consequently, for the past 9 years, we have been using free grafts of autologous fascia lata to replace deficient abdominal wall fascia and muscle in situations where prosthetic material is contraindicated and local tissue rearrangement (i.e., component separation) would be inadequate. Thirty-two patients (mean age 59 years) underwent abdominal wall reconstruction with autologous fascia lata grafts. Indications included exposed mesh (31 percent), enteric fistulae (28 percent), enteric contamination (22 percent), wound infection (13 percent), and immunosuppression alone (6 percent); 31 percent of all patients were immunosuppressed secondary to either a solid organ transplant or a systemic inflammatory disorder. Fascia grafts (mean size 10 x 17 cm) were sutured to the surrounding abdominal wall and covered by local skin flap advancement and/or myocutaneous flap rotation. All abdominal reconstructions were initially successful. Subsequent local abdominal wall complications included cellulitis (n = 3), seroma (n = 2), and skin dehiscence with exposed fascia grafts (n = 7). Five of seven patients with skin dehiscence healed by secondary intention, whereas two had split-thickness skin grafts successfully applied to the granulating fascia. Thigh donor site complications included hematoma (n = 1), skin dehiscence (n = 1), and seroma (n = 2). There have been no cases of lateral knee instability. The average follow-up period is 27 months (range 3 to 106 months). Recurrent hernia has been seen in three patients (9 percent). Interestingly, laparotomy has been performed through an intact fascia lata patch in three patients for unrelated intra-abdominal conditions. In each case, the graft was intact and revascularized, confirming experimental animal data performed in our laboratory. Recurrent hernia has not been observed through the laparotomy site. Our 9-year experience has demonstrated that in the face of large, contaminated abdominal wounds where prosthetic material is contraindicated and local tissue rearrangement would be inadequate, fascia lata autografts are a reliable adjuvant to abdominal wall reconstruction.

Human acellular dermal matrix for ventral hernia repair reduces morbidity in transplant patients.

PURPOSE: Organ transplantation is widely accepted as the treatment of choice for native organ failure. Due to required immunosuppression, however, organ recipients are prone to wound infections, incisional hernias, and fascial dehiscence. These complications are especially dangerous in this patient population, as they can compromise the survival of the transplanted organ. Various methods have been employed to repair ventral and incisional hernias in these patients. These include primary repair, synthetic mesh, biologic mesh, tensor fascia lata grafts (TFL), component separation, flaps from the thighs, or a combination of these. The goal of this study was to review the experience at our institution with ventral hernia repair in transplant patients and to compare outcomes of the various repair techniques. METHODS: Patients with liver, renal, or pancreas transplants requiring immunosuppression who underwent a ventral or incisional hernia repair at the University of Maryland from 2000-2005 were reviewed retrospectively. Factors examined include type and location of hernia, type of repair, post operative infection, hernia recurrence, reoperation, mesh removal, and length of follow up. Complication rates were compared using odds ratio and chi-square. RESULTS: A total of 104 patients met the criteria with a mean length of follow up of 26 months. Of these, 34 patients had repair with human acellular dermal matrix (HADM), 26 had synthetic mesh, 25 had primary repair, and 9 had TFL. Rates of wound infection in these groups were 15, 65, 8, and 11% respectively (χ (2) = 28, P < 0.001). Rates of recurrence were 24, 77, 36, and 11% respectively (χ (2) = 22, P < 0.001). The rate of mesh removal with HADM and synthetic mesh were 12 and 69%, respectively (χ (2) = 14, P < 0.001). When comparing HADM and synthetic mesh, the odds ratio for wound infection is 11 (95% CI 3.2-38) and for mesh removal is 8.7 (95% CI 2.6-28). CONCLUSION: When repairing ventral or incisional hernias in immunosuppressed transplant patients, HADM provides significantly reduced morbidity from reduced rates of infection, recurrence, and need for operative removal of mesh.

Case study: the role of surgical debridement and dural patching in the prevention of a recurrent radiation-induced sacral ulcer.

The effects of radiation are not tissue selective. Changes are consistent with thermal injury, but evolve in a more insidious manner. Erythema, edema, itching, and osteonecrosis can occur. These changes, over the sacrum, can lead to a spinal cutaneous fistula with persistent cerebrospinal fluid (CSF) leak in association with ulceration. Soft tissue coverage alone appears to be inadequate treatment. Aggressive bony debridement with dural patching have prevented recurrence of the fistula in a recent case.

Composite toe (phalanx and epiphysis) transfers in the reconstruction of the aphalangic hand.

Twenty children with ectrodactyly have had 36 digits reconstructed with toe phalanges inserted into the existing soft tissue finger pouches or pouches constructed with local tissue. Care is taken to preserve the periosteum, epiphyseal plate, and collateral ligaments of the transfers. No surgical microvascular anastomoses are performed, and the entire procedure takes less than 30 minutes. Epiphyseal patency rates in children with a mean follow-up of 3.4 years and a median of 4 years are 90% for those operated on at 6 months to 1 1/2 years of age, 67% in those operated on at 1 1/2 to 5 years, and 50% in children operated on at 5 to 13 years of age. Radiographic growth measurements show average growths greater than 90% of the expected growth based on measurements of the contralateral donor phalanx for all transfers with open epiphyses. These reconstructed digits provide fingers that are sensate, capable of pinch and grasp, and able to tolerate heavy use.

Hypertrophy of the abductor hallicus muscle: an unusual congenital foot mass.

A rare case of an isolated congenital muscle hypertrophy involving the abductor hallicus muscle is presented. Although the entity has not been well described previously, it should be entertained in the different diagnoses of medial childhood foot masses. Presently, the diagnoses of such masses should be made more easily with the widespread availability of magnetic resonance imaging. Treatment is generally straightforward, consisting of observation alone, versus partial or total excision, as dictated by the operative findings and previous functional impairment.

Development of a synthetic replacement for flexor tendon pulleys using expanded polytetrafluoroethylene membrane.

Reconstruction or replacement of the damaged pulley is a difficult surgical problem because of the need to find suitable biological material, the bulkiness of the repair, and adhesion formation between the pulley and flexor tendons. Therefore, a method was developed to reconstruct the fibro-osseous pulleys with polytetrafluoroethylene (PTFE) membrane. Twenty White Leghorn chickens had the A3 pulley of the long digit excised; this was followed by a standard injury to the flexor profundus tendon. The A3 pulley was then reconstructed with PTFE membrane. In the opposite foot, the A3 pulley was transected laterally, the tendon injured in the same manner, and the native pulley sutured. Seven control chickens had a PTFE pulley reconstruction without tendon injury in one foot and the opposite foot did not undergo surgery. At postoperative days 0, 21, and 35, the animals were killed to evaluate the effectiveness of the PTFE pulleys. Flexor tendon function was assessed by determining the active range of motion of the digit. There was no significant difference between the PTFE pulleys and suture repair of the native pulleys at postoperative days 21 and 35. This indicates that the PTFE pulleys were capable of preventing tendon bow-stringing and did not significantly impair tendon gliding. The breaking strength of the PTFE pulley was less than that of the normal A3 pulleys, but it was sufficient to allow immediate mobilization of the digits postoperatively without fear of pulley rupture. The synthetic PTFE pulley appears to have the potential to function as an effective immediate replacement for the fibro-osseous pulleys.

Technical modifications for on-site nipple-areola reconstruction.

There have been numerous techniques and refinements for nipple-areola reconstruction described that have required the use of distant donor sites. A further modification of the skate flap is described, whereby the entire reconstruction can be performed on site, thus avoiding a second scar and any subsequent morbidity. This technique is easy to perform and has all the advantages of the skate flap as described by Little.