The vacuum-assisted closure device as a bridge to sternal wound closure.

Sixteen patients were treated for sternal wound infections after undergoing cardiac procedures. Their management involved prompt surgical debridement and quantitative wound biopsies. At the time of the initial debridement, the Vacuum-Assisted Closure Device (V.A.C.) was placed in the open sternal wound. A subatmospheric environment was maintained by the device at a level of 75 to 150 mmHg. The V.A.C. sponge was changed every 2 to 3 days, and operative debridement was performed until quantitative biopsies showed resolution of infection or until systemic signs of sepsis had resolved. At this time the sternal wounds were closed with regional muscle flaps. Patients were excluded from the use of the device if the pleural cavity was entered during operative debridement. Fifteen of the 16 patients survived and went on to complete wound healing and discharge from the hospital (average length of stay, 16.7 days). One patient sustained a cardiac dysrhythmia during the muscle flap procedure and died. There were no complications related directly to the use of the V.A.C. It is the opinion of the authors that the V.A.C. offers several advantages over their traditional methods of treatment. They noted improvement in sternal wound stabilization during the perioperative period and a decreased need for paralysis and mechanical ventilation. Wound management was improved by avoiding the need to perform debridement or to make desiccating dressing changes to an open sternum. Moreover, they also think that this device may lessen the risk for ventricular rupture because of better control of the wound environment and markedly improved stabilization of the debrided sternal elements.

Quantitative swab culture versus tissue biopsy: a comparison in chronic wounds.

Soft tissue infection present a significant obstacle to the healing of chronic wounds. Historically, the gold standard for determining wound bacterial bioburden has been the quantitative tissue biopsy. Nevertheless, tissue biopsies are not universally used in today's healthcare setting. Likely reasons include damage to healing tissue, the lack of facilities to process tissue biopsies, significant pain in sensate soft tissue, and increased expense with this modality. More recently, quantitative tissue swab culture has been suggested as a means to determine the wound bioburden. The authors prospectively studied 38 patients with chronic wounds of various etiologies to evaluate the correlation between quantitative wound biopsy and swab culture. Of the 38 biopsies performed, 74% indicated infection. Simultaneous swab culture of these 28 biopsies indicated infection in 22 of the 28 cases for a correlation of 79%. The authors concluded that quantitative swab culture provides a valuable adjunct in the management of chronic wounds.

Thrombogenic effects of a nonthrombin-based fibrin sealant compared with thrombin-based fibrin sealant on microvenous anastomoses in a rat model.

The efficacy and safety of tissue adhesives needs to be clearly defined. A thrombin-based preparation of fibrin sealant has recently been shown to have deleterious effects on microvascular anastomoses in an animal model. The authors found that fibrin sealant constructed with a high concentration of bovine thrombin (1,000 IU per milliliter) was detrimental to microvascular patency when applied to the anastomosis in a rat free flap model. The microvenous anastomosis had the highest rate of thrombosis and failure in this model. A nonthrombin-based fibrin sealant has recently become available for experimental investigation. This study examined the thrombogenic effect of this nonthrombin-based fibrin sealant on microvenous anastomoses in a rat free flap model compared with the effect of traditionally prepared fibrin sealant with varying concentrations of thrombin. The conclusions reveal that flap survival with application of the nonthrombin-based fibrin sealant to the anastomosis was comparable with flap survival of the control animals. Flap survival with application of the traditionally prepared thrombin-based fibrin sealant was also comparable with flap survival of the control animals when a concentration of 500 IU per milliliter of thrombin was used. However, flap survival decreased significantly (p <0.005) when a concentration of 1,000 IU per milliliter of thrombin was used in the construct of the fibrin adhesive. These results support the previous findings of the harmful effects of thrombin when used in high concentrations and applied to the microvenous anastomosis of this free flap model. Moreover, this initial investigation with a nonthrombin-based fibrin sealant did not show any deleterious effects on the microvenous anastomosis compared with control animals.

Isolated musculocutaneous neuropathy caused by a proximal humeral exostosis.

We report an isolated musculocutaneous neuropathy caused by a proximal humeral osteochondroma that became symptomatic after the patient played recreational basketball. Lesion resection resulted in complete deficit resolution. Mass lesions involving the musculocutaneous nerve should be considered in patients with atraumatic, isolated musculocutaneous neuropathies that are recurrent or fail to recover, even in the setting of strenuous exercise.

A pilot study of short- and long-term sequelae to rigid fixation across metacarpal physes in a baboon model.

The use of rigid fixation for fractures of the extremities has become commonplace. The short- and long-term effects of rigid fixation on the growing hand, however, have not been studied thoroughly. In this project, the use of rigid fixation across metacarpal growth plates (physes) in growing primate hands was examined. The hypothesis to be tested was that long-term placement of rigid fixation devices across physes during stabilization of mid-shaft osteotomies will cause the physes to close prematurely. Fixation devices with screws placed in the epiphysis and left in place for 4 months or 1 year resulted in open physes, in support of the null hypothesis. However, in physes plated for 1 year, biochemical changes associated with increased bone differentiation were apparent. Findings suggest that rigid fixation across physes for as long as 1 year can be used appropriately in growing individuals when necessary. However, until additional investigation establishes whether the open physes are still capable of producing bone-lengthening hypertrophic chondrocytes, caution should be used in long-term placement of rigid fixation devices.

Repair of a rodent nasal critical-size osseous defect with osteoblast augmented collagen gel.

OBJECTIVES/HYPOTHESIS: Facial skeletal defects are a common challenge for the otolaryngologist. Type I collagen gels have shown promise in the repair of nonhealing critical size defects (CSDs) of facial bone by providing scaffolding for new bone growth by osteoblasts at the defect perimeter. The objective of the present study was to evaluate the effect that suspending osteoblasts within a type I collagen gel has on the repair of a rodent facial CSD. STUDY DESIGN: Randomized controlled trial using a rodent model. METHODS: A previously described facial CSD was created by removing the nasalis bones with a cutting burr to the level of the nasal mucosal membranes on 18 Sprague-Dawley rats. Groups of six animals were treated with an implant containing either 300 microg of type I collagen gel, 12 x 10(5) osteoblasts suspended within type I collagen gel, or 12 x 10(5) fibroblasts suspended within type I collagen gel for comparison. After 30 days the animals-were examined at necropsy with planimetry, histological analysis of new bone growth, and radiodensitometric analysis of bone thickness. RESULTS: All animals had complete coverage with a thin layer of bone. Histological sectioning revealed an increased thickness in the osteoblast augmented group. Radiodensitometric measurements revealed a statistically significant increase in bone repair in the osteoblast group compared with the collagen-only group (P < or = .0005) and the fibroblast group (P < or = .04). CONCLUSION: Type I collagen gels augmented with an osteoblastic suspension significantly enhance the repair of nasal CSDs in a rodent model. The use of cultured bone precursor cells represents a leap forward in osteoengineering.

Insulinlike growth factor 1- and 2-augmented collagen gel repair of facial osseous defects.

BACKGROUND: Defects of the facial bone structure are common problems for the facial plastic surgeon. Native type 1 collagen gels (T1CGs) have been shown to mediate repair of facial critical-size defects in rat models. OBJECTIVE: To evaluate the efficacy of T1CG augmented with insulinlike growth factor (IGF) 1, IGF-2, and a combination of IGF-1 and IGF-2 on the repair of facial critical-size defects in a rodent model. METHODS: Twenty-four retired male breeder Sprague-Dawley rats were divided into 4 groups of 6 animals. Facial critical-size defects were created by removing the nasalis bones with a bone-cutting drill. Defects were treated with 300 pg of type 1 collagen gel (T1CG), T1CG augmented with 3 microg of IGF-1, T1CG augmented with 3 microg of IGF-2, or T1CG augmented with a combination of 3 microg of IGF-1 and 3 microg of IGF-2. After 30 days the animals were examined at necropsy with precise planimetry, histological analysis of new bone growth, and radiodensitometric analysis of bone thickness. RESULTS: Radiodensitometric measurements showed that IGF-2 augmentation resulted in greatest osseous healing, with measurements being statistically significant over those of all other groups (P< or = .03). Combination IGF-1 and IGF-2 had osseous healing that was intermediate between IGF-1 augmentation and IGF-2 augmentation alone, with measurements being statistically significant over those of unaugmented gels (P<.001) and IGF-1 augmentation (P< or = .03). Augmentation with IGF-1 resulted in healing that was significant over that of unaugmented gels (P< or = .04). CONCLUSION: Collagen gels augmented with IGF significantly enhance the osteoconductive repair of nasal critical-size defects in a rodent model, with IGF-2 showing highest efficacy.

Wound complications of abdominoplasty in obese patients.

The records of 90 patients who underwent an abdominoplasty at the University of Virginia Health Sciences Center were analyzed to determine the effect of obesity on the incidence of complications after this surgery. The study patients were divided into three groups-obese, borderline, and nonobese-based on the degree to which their preoperative weights varied from their ideal body weight. A history of previous bariatric surgery was also analyzed to determine what impact that might have on subsequent abdominoplasty. Results showed that 80% of obese patients had complications compared with the borderline and nonobese patients, who had complication rates of 33% and 32.5% respectively (p = 0.001). Previous gastric bypass surgery had no significant effect on the incidence of postabdominoplasty complications. Based on these findings the authors conclude that obesity at the time of abdominoplasty has a profound influence on the wound complication rate following surgery, regardless of any previous weight reduction surgery.

A new technique for the treatment of flexor digitorum profundus tendon avulsion.

Current treatment of flexor digitorum profundus (FDP) avulsion with complex external wire or button fixation is associated with significant morbidity. A new method of internal fixation avoids the complications that are associated with previous techniques. Through a volar Bruner incision, the profundus tendon is retrieved. A transverse dorsal incision is made and two holes are drilled. A double-arm suture is passed through the tendon and bone, and is tied dorsally. Both incisions are closed, leaving the repair entirely internal. This simple technique produces a solid reinsertion of the FDP tendon and avoids damage to the nail bed and matrix. Internal fixation eliminates nail plate deformities, reduces cost, speeds recovery, and produces a stable reconstruction.

Acute thrombogenic effects of fibrin sealant on microvascular anastomoses in a rat model.

Topically applied bioadhesives and hemostatic agents have gained wide acceptance in various surgical endeavors. However, the effect of thrombin-based fibrin sealant (fibrin glue) when applied to microvascular anastomoses has not been evaluated thoroughly. Although fibrin sealant has been used directly on vascular anastomoses in macrovascular surgery, there has been little exploration into the utility and potential complications when used in the microsurgical setting. This study explored the influence of fibrin sealant containing increasing concentrations of bovine thrombin on microvascular anastomoses in a rat epigastric free flap model. The survival of the free flap in this model appeared to be inversely proportional to the concentration of thrombin in the fibrin sealant. When thrombin alone was applied to the anastomoses, the rate of thrombosis was the highest. Venous anastomosis was the most sensitive to the deleterious effects of topically applied thrombin.

Treatment of adolescent gynecomastia using a bipedicle technique.

Many methods have been described for the treatment of gynecomastia. Eleven adolescent boys have been managed with a bipedicle technique. These patients were evaluated for nipple-areolar viability, scarring, patient satisfaction, and hematoma or seroma formation. The pedicles providing blood supply to the nipple-areolar complex are reliable and are derived from the dermis and glandular breast tissue, thus minimizing nipple-areolar necrosis and hypopigmentation as a complication of the procedure. A periareolar incision provides adequate exposure for safe dissection and excision of the breast tissue, and facilitates reduction in the complex if needed. Good to excellent results were reported in all 11 patients at 2 weeks to 13 months of follow-up. There was no evidence of nipple-areolar necrosis and only one case of postoperative seroma formation. This approach utilizes a safe and reliable method of breast reduction that is particularly effective in the male adolescent group.

Asymptomatic jaundice after fasting: a diagnostic dilemma.

An 18-year-old female with asymptomatic jaundice presented to the emergency department after fasting. She was referred to the regional medical center for evaluation and treatment. The diagnosis of Gilbert's syndrome was made by fractionation of serum unconjugated and conjugated bilirubin fraction by alkaline methanolysis, followed by thin-layer chromatography and analysis of fasting-state levels of cholyl conjugated bile acids. Methods for diagnosing this disorder are discussed.

Surgical glove lubricants: from toxicity to opportunity.

In most emergency departments, surgical gloves are coated with surface powders that act as lubricants to facilitate donning. Cornstarch powder is an absorbable powder employed as a donning agent on most powdered gloves. Talcum powder, a nonabsorbable powder, is used as a mold release agent in glove manufacture and is still commonly found on the surfaces of modern surgical gloves. These powders are foreign bodies that elicit inflammatory responses, leading to a wide number of symptoms and complications. The best method of preventing clinical complications from glove powder is to use powder-free gloves.

Accidental hypothermia: a potential life-threatening hazard of automobile platform lifts.

The wheelchair/scooter of a patient with a relapsing-remitting form of multiple sclerosis was immobilized after inadvertent slippage of the rear wheels of his scooter off an automobile platform lift during travel. While waiting 45 min for the rescue squad, he developed mild hypothermia that responded to passive external rewarming techniques. This potentially life-threatening injury could have been prevented by using a platform lift equipped with full inboard and outboard roll-stop barriers on the platform.

Seroma prevention in a rat mastectomy model: use of a light-activated fibrin sealant.

Seroma formation following mastectomy and axillary dissection remains a common and significant problem contributing to patient morbidity and health-care costs. Previous data have suggested that fibrin sealant (FS), a biological adhesive, is capable of controlling lymphatic leakage and assisting with skin graft adhesion. In this study, the use of an experimental, light-activated FS under development by CryoLife (CFS) was evaluated in a rat mastectomy model in order to reduce seroma formation. CFS is a premixed form of FS, containing an inactivator that is reversed in the presence of light, causing sealant to form. In this model, rats underwent mastectomy and extensive dissection of the axillary lymphovasculature. Next, 1 ml of saline or FS was applied to the operative site and the wound was closed. Three groups of animals were evaluated 5 days postoperatively by measuring the volume (in milliliters) of seroma able to be aspirated from the surgical site. The saline control group (N = 20) had a seroma volume (mean +/- standard deviation [SD]) of 4.2 +/- 2.9 ml, while a form of CFS containing human fibrinogen (80 to 100 mg per milliliter) and human thrombin (20 U per milliliter) (N = 20) had a significantly smaller seroma volume of 1.1 +/- 1.6 ml (p < 0.001 analysis of variance). University of Virginia (UVA) FS, containing human fibrinogen (20 mg per milliliter) and bovine thrombin (500 U per milliliter) (N = 20), had a seroma volume of 2.0 +/- 1.6 ml (p < 0.01, compared to control; p > 0.2, compared to CFS). Thus, this form of CFS significantly reduced seroma formation compared to saline control and also appeared to result in a smaller fluid accumulation than with UVA FS, although this trend was not statistically significant. These data suggest that the use of CFS may help to reduce seroma formation in humans.

Effect of fibrinogen and thrombin concentrations on mastectomy seroma prevention.

Seroma formation remains a significant clinical problem which increases morbidity and hospital costs in patients undergoing mastectomy operations. This study evaluated the effect of varying the concentrations of fibrinogen and thrombin in fibrin sealant on successfully preventing seroma formation in a rat model. After axillary dissection, control animals (Groups I and II) had 1 ml of either normal saline or thrombin (100 U/ml) applied to the axilla while treated animals (Groups III-VIII) had increasing concentrations of 0.5 ml of fibrinogen (25, 50, or 100 mg/ml) and 0.5 ml of thrombin (10 or 100 U/ml) applied. Seroma volumes (means +/- standard deviation) were measured on Postoperative Day 5. They were largest in Group I (3.1 +/- 1.9 ml, n = 13) and Group II (3.9 +/- 2.7 ml, n = 15) and then decreased from a high in Group III (2.5 +/- 2.4 ml, n = 15) using fibrinogen, 25 mg/ml, and thrombin, 10 mg/ml, to a low in Group VIII (0.8 +/- 1.0 ml, n = 15) using fibrinogen, 100 mg/ml, and thrombin, 100 U/ml. Analysis of variance revealed a statistically significant difference in the mean seroma fluid volumes between the groups (P = 0.0021), while Scheffe's comparison showed a specific significant difference (P = 0.028) between the thrombin control (Group II) and the highest concentration fibrin sealant (Group VIII). The difference in seroma volumes for all control animals (Groups I and II), 3.5 +/- 2.4 ml, and all treated animals (Groups III-VIII), 1.7 +/- 2.1 ml, was highly significant by unpaired t test. (P < 0.0001). Thus, fibrin sealant was useful in reducing seroma formation in this rat model with the highest concentration of fibrinogen and thrombin appearing most effective. These data may be useful in guiding future clinical trials in humans.

Nasal reconstruction using an osteoconductive collagen gel matrix.

BACKGROUND: Congenital malformations, granulomatous diseases, and trauma can all cause destruction of the nasal structural framework, resulting in functional nasal obstruction and altered facial cosmesis. Current methods of nasal reconstruction include cartilaginous and bony grafts, Silastic implants, and homograft only materials. However, these techniques have significant functional and cosmetic drawbacks and are not risk free. Native, isotonic, neutral-pH, space-filling type I collagen gels have been shown to mediate total repair of critical-size collagen grafts provide a framework for rapid intramembranous ossification and osteoconduction of bone from the perimeter of a defect, resulting in total bony coverage. OBJECTIVE: To evaluate a novel approach to nasal reconstruction using a major defect of the bony nasal dorsum with a type I collagen gel matrix. DESIGN: Sixteen retired male breeder Sprague-Dawley rats were divided into control and experimental groups. The nasal bones were exposed through a dorsal incision and completely removed with a bone-cutting drill to the level of the mucosal membranes of the nasal vestibule. Defects in the experimental animals were then implanted with 200 micrograms of type I collagen gel, with control animals receiving no inlay. After 6 weeks, the animals were examined with three-dimensional computed tomography before necropsy, at which time the defects were photographed, measured by planimetry, and sectioned for histologic analysis. RESULTS: Experimental defects were observed to manifest 100% surface area healing with a thin layer of bone using a type I collagen gel osteoconductive implant for nasal reconstruction. Conversely, control animals showed only a 5.7% (+/- 3.7% SD) healing by area. Histologic sections of the collagen gel implant revealed restoration of the anatomy with a thin plate of immature bone spanning the defect in continuity with the cartilage of the nasal septum and with apparent preservation of maxillonasalis suture lines. CONCLUSIONS: Native, isotonic, neutral-pH, space-filling collagen gels positively influenced the repair of large nasal defects, which showed minimal bone closure in untreated animals. Their use in this role merits further investigation.

Needle puncture resistance of surgical gloves, finger guards, and glove liners.

New puncture resistant materials are being developed for health professional use as protection against disease and needle stick injuries. The needle puncture resistance of protective gloves and glove liners from DePuy DuPont Orthopaedics and of finger guards from Zimmer was evaluated using a computerized needle penetration system to determine maximal penetration forces and the penetration work required for taper point and for cutting edge needles to penetrate these membranes. The Medak portion of the Life Liner glove liner and the Spectra portion of the FingGuard finger guard offered remarkable resistance against needle penetration as compared to the other glove liners and gloves tested. The cutting edge needles required considerably less penetration force and work to penetrate the FingGuard and Life Liner than that required with comparable size taper point needles. Because these unique protective materials had a limited distribution over the hand, the surgeon's hand remained susceptible to inadvertent needle puncture. While this protection against needle penetration in the Life Liner and the FingGuard represents an exciting advance in surgery, it is important to emphasize that this development is only one consideration in the selection of surgical gloves.

Secondary ischemic tolerance improved by administration of L-NAME in rat flaps.

Nitric oxide (NO) under basal conditions is an important regulator of vascular tone. Under ischemic conditions, however, NO can combine with superoxide anion to produce the damaging hydroxyl free radical. The current project observes the effect of inhibiting NO production (L-Nitro-amino-methyl-arginine, L-NAME) on flaps rendered ischemic by secondary (2 degrees) venous obstruction. Eighty rats had 3 x 6 cm skin flaps based on the epigastric vessels. Primary (1 degree) ischemia was produced by arteriovenous occlusion for 2 hours; (2 degrees) venous ischemia was induced by clamping the vein, alone for either 3 or 5 hours. Thirty minutes prior to 2 degrees ischemia, rats received either L-NAME (30 mg/kg) or saline buffer. Flap survival was assessed 7 days later and Chi-square analysis was used. At 3 hours of ischemia, treatment improved survival from 55% to 85% (P < 0.05). Treatment also improved survival at 5 hours of ischemia from 5% to 35% (P < 0.04). Although under resting conditions, NO is a potent vasodilator, during 2 degrees venous obstruction it may contribute to flap necrosis.

A rapid in vitro assay of cellular chemomigration in an epithelial carcinoma cell line.

We have studied the chemomigration activity of an epithelial carcinoma cell line using a modified 96-well Boyden chamber apparatus consisting of upper and lower wells separated by an 8-microns pore polycarbonate filter. Cells from the malignant squamous carcinoma cell line A-431 were plated in the upper wells over a collagen IV-coated filter. In chemokinesis assays, the cells were allowed to migrate toward NIH 3T3 fibroblast-conditioned medium or control media in the lower wells for 6 hours at 37 degrees C with 10% CO2. A-431 cells preferentially migrate across the barrier toward conditioned media but not control media. Control normal keratinocytes showed no migration. A highly metastatic melanoma cell line and poorly metastatic melanoma cell line, in which chemomigration has been shown previously to correlate with metastatic potential, were used as positive and negative cellular controls. This system provides a rapidly quantifiable method by which the invasion characteristics of multiple cell lines can be studied simultaneously in a single assay using the 96-well format.