Biomedical subjects
Publications and source records attributed to R L McCauley.
The use of tissue expanders in reconstructive surgery has become well established, but their use has been associated with multiple complications. Salvage of expanded tissue after traumatic extrusion of the prosthesis has not been previously reported. We have outlined the principles involved in the management of such a case, and reviewed previously reported complications of tissue expansion.
Topical antimicrobial agents are essential to optimal burn care. However, exposure of WI-38 human diploid fibroblasts (ATCC CCL 75) and fresh donor human dermal fibroblasts to silver sulfadiazine and mafenide acetate results in a significant reduction in cell proliferation, as determined by hemocytometer cell counts and total matrix protein assays, within 48 hr of exposure. Changes in cellular morphology and progressive deterioration of cytoplasmic organelles and the nucleus are seen with phase-contrast microscopy and transmission electron microscopy. These findings may explain the clinical observation of delayed wound healing after the use of topical antimicrobial agents.
Long-term follow-up of breast development in adolescent female patients with burns of the anterior chest wall is poorly documented. Between 1971 and 1976, 28 female patients with photographic documentation of burns to the anterior chest wall involving the nipple-areolar complex were reviewed. All patients were followed at least until their early teens. The mean age at the time of thermal injury was 5.9 +/- 2.5 years, with a mean follow-up time of 8.9 +/- 2.6 years. Thirteen patients (46 percent) were admitted to the Shriners Burns Institute in Galveston for acute care of their burns. Fifteen patients (54 percent) were referred for long-term follow-up or specific reconstructive procedures following care of the acute burns. In spite of significant thermal injury to the anterior chest wall with involvement of the nipple-areolar complex, no patient failed to develop breasts. Twenty patients (71 percent) required releases of the anterior chest wall to assist breast development. All anterior chest wall releases were accomplished with the use of skin grafts or local skin flaps.
Thirty patients with systemic necrotizing vasculitis (SNV) of the polyarteritis nodosa type were reviewed. Eleven patients (36%) had only gastrointestinal manifestations of the disease. Four patients (13%) had only pulmonary involvement. Seven patients (23%) had both gastrointestinal and pulmonary manifestations of SNV. With use of an approved protocol from the National Institute of Allergy and Infectious Diseases of cyclophosphamide and prednisone, remission was attained in 29 of 30 patients (96%). However, 18 patients (60%) underwent major surgical procedures for either diagnosis or complications of the disease. Six patients underwent eight thoracotomies; six operations were required for diagnosis and two for drainage of right-sided empyemas. Ten patients underwent 14 exploratory laparotomies. Six abdominal explorations were performed for diagnostic purposes, and eight were required for treatment of complications. Two patients required digital amputations because of ischemic necrosis. Two patients (11%) developed five postoperative complications, one of whom subsequently died. Arteriographic studies were performed in 16 patients (53%). Vascular abnormalities consistent with those described for SNV were demonstrated in six cases (38%). There was no correlation of clinical manifestations, subsequent therapy, and arteriographic findings with regard to the development of intra-abdominal complications. Pulmonary complications occurred only in patients who had pulmonary infiltrates secondary to SNV.
Previous research has implicated arachidonic acid metabolites in the failure of the distal dying flap. The progressive ischemic necrosis has been postulated to be secondary to excessive thromboxane A2 production, which upsets the normal balance between prostacyclin and thromboxane. We have examined the effect of continuous intraarterial prostacyclin infusion on axial skin flap survival in the pig, in an effort to reestablish homeostasis. We found prostacyclin to have a biphasic effect upon the flap survival. Low-dose locally administered prostacyclin was of benefit in flap salvage; however, the complicated pharmacological effect of the agent is emphasized.
The supraclavicular lymph nodes are known as a potential site for metastatic disease of the gastrointestinal and genitourinary cancers. The values of supraclavicular node biopsy in patients undergoing staging for testicular cancer were studied prospectively. Of 108 patients with testicular cancer undergoing therapy, 26 had supraclavicular node biopsy as part of their staging procedure. Evidence of metastatic disease to the supraclavicular nodes was found in 36% (10/26) of the patients. Ten of these patients had abnormal examinations of the supraclavicular fossa and nine of them (90%) had histologic evidence of metastatic disease. However, of the 16 patients with normal examination of the supraclavicular fossa, only one patient (6.3%) presented with clinically inapparent metastatic disease. The low yield for detection of clinically inapparent metastatic disease mitigates against indiscriminate supraclavicular node biopsy in the staging of testicular carcinoma.
Serum albumin concentration is commonly used as an index of nutritional status and as an indicator of nutritional response in hospitalized patients receiving total parenteral nutrition (TPN). One hundred thirty-nine cancer patients receiving TPN for at least two weeks were studied. Albumin intake, serum albumin, fluid balance, and weight change was monitored from 14 to 100 days of TPN. Patients were classified into three groups: A) patients receiving no exogenous albumin; B) patients receiving less than 25 grams of exogenous albumin; and C) patients receiving at least 25 grams of exogenous albumin during their course of TPN. Linear regression analysis of serum albumin levels vs. time on TPN showed a minimal positive correlation for patients in groups B and C (r = 0.154 and r = 0.183, respectively). Further analysis showed a significant elevation of serum albumin levels only in patients in group C (p less than or equal to 0.05). Contingency table analysis showed statistically significant increase in the incidence of sepsis in patients treated with exogenous albumin (X2 = 10.50, df = 2, p less than 0.01). There was no relationship between the change in serum albumin concentrations and the number of patient deaths. In addition, no relationship between tumor burden and subsequent response of serum albumin levels were identified. Serum albumin levels do not increase in cancer patients receiving TPN, unless exogenous albumin is given. Serum albumin appears to be a poor index of nutritional response in cancer patients receiving TPN.
The breakdown products of arachidonic acid have been implicated as mediators of progressive dermal ischemia in both cold and thermal injuries. Increased tissue survival can be demonstrated experimentally with the preservation of the dermal microcirculation by using antiprostaglandin agents and thromboxane inhibitors. Thirty-eight consecutive patients (28 males and 10 females aged 2 mo to 46 yr) with frostbite injuries were treated at the University of Chicago's Burn Center in January 1982 with a protocol designed to decrease the production of thromboxane locally and prostaglandins systemically. All patients recovered without significant tissue loss. The average hospital stay was 5.6 days for acute injuries and 6.9 days for subacute injuries.
Essential to the success of optimized thermal treatment during hyperthermia is accurate modelling. Advection of energy due to blood perfusion significantly affects the temperature. Without accurate estimates of the magnitude of the local tissue blood perfusion, accurate estimates of the temperature distribution can not be made. It is shown here that the blood mass flow rate per unit volume of tissue in the Pennes' bio-heat equation can be modelled using a relative perfusion index (RPI) determined with dynamic-enhanced magnetic resonance imaging (DE-MRI). Temperature distributions in two patients treated with hyperthermia at Duke University Medical Center for high-grade leg tissue sarcomas are modelled, and the resultant temperatures are compared to measured temperatures using a non-invasive MR thermometry technique. Significant correlations are found between the DE-MRI perfusion images, the MR temperature images, and the numerical simulation of the temperature field. The correlation between DE-MRI measured values and advective heat loss in tissue is used to scale the perfusion distribution, thereby allowing the continuum model to account for the local thermal impact of vasculature in the tumour. Large vessels in tumour and neighbouring healthy tissue need to be taken into account in order to accurately describe the complete temperature distribution.
The rehabilitation and reconstruction of patients who survive large burns is an arduous task. To facilitate it we have devised an inventory form to accurately record the somatic abnormalities caused by burns and also the severity and location of burns. This form was used in the assessment of 25 pediatric patients with massive burns. It was found to be a very useful tool that allowed the identification of more specific functional and esthetic deformities than is possible with currently available forms. It also served as a template for the systematic planning of reconstructive procedures.
Burns to the buttocks are rare. Gluteal pouching, a complication of burn scar contractures of the buttocks, with total effacement of the gluteal folds and hooding of the rectum is described. A barium enema is helpful for preoperative evaluation. Recreation of the gluteal folds and unhooding of the rectum can be performed effectively without skin grafting.
Between 1966 and 1986, fifty-seven pediatric patients with partial and/or full-thickness perineal and genital burns with a minimum of 1-year follow-up were identified. Fifty percent of the patients with genital burns and 20% of the patients with perineal and/or buttock burns required skin grafting in the acute stage. No patient required suprapubic cystostomies, diverting colostomies, or local flap coverage of exposed testicles. Burn scar contractures were the most frequent complications. Thirty-two patients (56%) required contracture release of the perineum and coverage with either skin grafts or local skin flaps. In three patients (6%) contracture required release of the penis and scrotum. One patient lost a testicle. Three patients developed rectal prolapse and were treated without surgery. Four patients developed rectal stenosis with fecal incontinence because of burn scar contracture and were treated by anal dilatation, local transposition flaps, and/or excision of the scar and primary closure. Acute management of pediatric patients with such injuries can be conservative. Delayed complications of contractures of the perineum and genitals can be easily corrected with scar excisions, skin grafts, or the use of local skin flaps.
The role of soluble inflammatory mediators in the wound healing process is under investigation. Interleukin 2 (IL2), an immune modulator produced by T lymphocytes, was tested in vitro for its effects on human diploid fibroblasts. Human diploid fibroblasts (1.0 x 10(4)) were incubated for 24 hours in Alpha minimal essential media (Gibco Laboratories, Gaithersburg, Md.) at 37 degrees C in 5% CO2 in air with 500 U/ml of IL2 (Cetus Corp., Emeryville, Calif.). Cells were then pulsed with 3 mu Ci/ml of tritiated thymidine overnight. The mean increase in the incorporation of tritiated thymidine of the cells treated with IL2 over control cells was 38% (p value less than 0.05). Interleukin 2 has a significant effect on the metabolism of human dermal fibroblasts and may accelerate the wound healing process.
Longitudinal assessment of the long-term effects of pediatric circumferential truncal burns on subsequent pregnancies is poorly documented. Between December 1967 and August 1985, 75 female pediatric patients with circumferential truncal injuries were admitted to our institution. Twenty-two of these patients were available for long-term follow-up into early adulthood. Seven of these 22 patients had conceived. All seven patients had sustained flame-burn injuries. Mean age at injury was 7.66 +/- 2.12 years. Mean total body surface area of burns was 63.21% +/- 16.69%, with 44.21% +/- 17.54% of the injuries full thickness. Each patient was treated with excision and split-thickness skin grafting during initial hospitalization. In the group of seven patients there were 14 pregnancies. All infants were full term. There were 13 vaginal deliveries and one elective cesarean section. Prenatal complications were limited to one case in which a patient had sustained breakdown of scar tissue during the third trimester of pregnancy. There were no labor and delivery complications in this patient population. Circumferential truncal burns appear to have no impact on prenatal or labor and delivery complications.
Toxic effects of sodium hypochlorite on wound healing elements have been confined to a restricted range of sodium hypochlorite concentrations. We investigated concentrations of sodium hypochlorite for antibacterial activity and tissue toxicity at varying time intervals. We attempted to find the efficacious therapeutic concentration that was both microbicidal and nontoxic. Gram-negative and gram-positive isolates (0.1/ml of 1 x 10(8)/ml) were introduced into various concentrations of buffered and unbuffered sodium hypochlorite solutions for determinations of bactericidal activity at 5-, 10-, 15-, and 30-minute intervals. Concentrations of sodium hypochlorite were 0.25%, 0.025%, and 0.0125%. In vitro assays with fibroblasts at the same concentrations were also performed to determine toxicity at the same time intervals. An in vivo incisional model was also used to determine the effects of sodium hypochlorite therapy on wound healing. Bactericidal effects were observed for concentrations as low as 0.025%. Tissue toxicity, both in vitro and in vivo, was observed at concentrations of 0.25% but not at a concentration of 0.025%. Although concentrations below this level were nontoxic, they were not bactericidal. Therefore a modified "Dakin's" solution at a concentration of 0.025% is therapeutically efficacious as a fluid dressing, since it preserves bactericidal properties and eliminates the detrimental potential on wound healing.
Cultured epithelial autografts have been advocated for permanent closure of skin surfaces after massive thermal injuries. A 10-year-old boy sustained a nearly 100% total body surface area burn (98% full-thickness) in an explosion accident. Cultured epithelial autograft was used to cover 70% of the total body surface area on postburn day 26. In spite of early success of coverage, 60% of cultured epithelial autograft areas blistered and sloughed over the ensuing weeks. Electron microscopic examination of a biopsy specimen of the healed cultured epithelial autograft (80 days after placement) revealed a lack of dermal attachments of the anchoring fibrils. Additionally, blister fluid that was taken from the bullae of the cultured epithelial autograft revealed levels of 18 ng/ml thromboxane and 24 ng/ml prostaglandin E2. These levels are significantly higher than those seen in acute burn blister fluid and indicate an ongoing inflammatory process. Cultured keratinocytes, although they provide early wound closure, may not provide adequate long-term coverage for patients with massive burns.
The cardiopulmonary performance levels in children who are convalescing from thermal injury are unknown. This investigation was designed to evaluate cardiopulmonary function in children with and without inhalation injury. Forty children with a mean time since burn injury of 2.6 +/- 1.9 years and a mean burn size of 44% +/- 22% total body surface area were selected for the study and divided into two groups: inhalation injury (group 1) and non-inhalation injury (group 2). Pulmonary function studies and cardiopulmonary stress testing were completed on all patients. Both groups reached the same endurance level on the treadmill; however, patients in group 1 did so with an increased expired volume, respiratory rate, and ratio of dead space ventilation to total ventilation which indicated that there were greater demands on the respiratory system. Spirometry and lung volumes at rest showed that 64% of patients in group 1 had abnormal lung function compared with only 27% of patients in group 2.
Burn scar contractures of the foot cause significant morbidity. We reviewed 68 children in regard to number and rates of burn scar contracture recurrence, surgical techniques, and functional and aesthetic results. Two surgical techniques of foot burn scar contracture release have been used. Originally, an incision over the metatarsal heads perpendicular to the line of the metatarsals, which releases the longitudinal arch of the foot was used. More recently, additional releasing incisions parallel to the plane of the metatarsals to release the transverse metatarsal arch have been used. The time between burn injury and primary burn scar contracture release was 4.18 +/- 0.76 years, and the time until the first recurrence was 3.44 +/- 0.46 years. With release of only the longitudinal arch, recurrence of burn scar contractures occurred in 3.5 +/- 0.41 years and in 4.29 +/- 1.27 years in six patients who also received release of the transverse arch. Wound closure at the time of acute burn with split-thickness skin graft expansion ratios of 1:2 and 1:4 had burn scar contractures that required release in 4.21 +/- 0.70 and 2.29 +/- 0.52 years, respectively.