Raymond F. Morgan

Analysis of the kinetics of peritoneal adhesion formation in the rat and evaluation of potential antiadhesive agents

BACKGROUND Peritoneal adhesions continue to be a significant cause of postoperative complications. Elucidating the origin of these adhesions has been hampered by the lack of a reproducible animal model. The purpose of this study was to create a standardized model in which a single, specific adhesion could be objectively measured. With this model the kinetics of adhesion formation were then evaluated. A variety of potential antiadhesive agents were then tested and compared. METHODS In this study a reproducible, quantitative rat model was developed that used uniform defects on the peritoneal wall and cecal surface. The resulting adhesions were subsequently scored, and their strength was measured with a tensiometer. An evaluation of the kinetics of peritoneal adhesion formation was obtained by using a timed removal of silicone elastomer sheeting held between the two injured surfaces. The following antiadhesive agents were evaluated: Ringers lactate solution; dextran 70 (32%); modified carboxymethylcellulose (1.0% and 2.0%); an absorbable barrier of specially knitted material composed of oxidized regenerated cellulose; fibrin sealant; silicone elastomer film; and expanded polytetrafluoroethylene membrane. RESULTS Evaluation of the kinetics of peritoneal adhesion formation indicated that the susceptibility for adhesion formation was significantly decreased or eliminated after the first 36 hours. Evaluation of antiadhesion agents indicated that the magnitude of adhesion prevention was directly proportional to the agents ability to remain at the site of injury during the critical period of adhesion formation. Permanent barriers (silicone elastomer film, expanded polytetrafluoroethylene membrane) provided the greatest antiadhesion effect but were not believed to be ideal agents because they remained at the site of injury well after the critical period of adhesion formation. The incidence of adhesion formation for the other agents was as follows: control (34 of 34), Ringers lactate (12 of 12), absorbable barrier of knitted cellulose (10 of 10), 32% dextran 70 (8 of 12), 1% carboxymethylcellulose (6 of 12), fibrin sealant (4 of 9), and 2% carboxymethylcellulose (4 of 12). CONCLUSIONS The efficacy of antiadhesion agents appears to be related to the agents viscosity, ability to coat the wound surface, and residence time at the site of injury. In this rat model an agent that remained on the injured surfaces for at least 36 hours after injury appeared to be more effective in reducing adhesion formation than an agent with a shorter residence time.

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.

Pelvic recurrence of rectal cancer. Options for curative resection.

Pelvic recurrence is an ominous event after curative resection of rectal cancer and is rarely amenable to re-resection by conventional methods. A method to permit a composite resection of these using the abdominal sacral approach has been described previously. This report updates that experience with resection of pelvic recurrence of rectal cancer in 28 patients. Of these, 24 were done with curative intent, and four were done for palliation (mainly for infected or fungating tumor). All patients had extensive preoperative evaluation by clinical and radiologic tests, and most patients had a long free interval period of approximately 18 months, after their primary resection. Although 47 patients had exploratory surgery, only 29 had local disease amenable to resection and four had palliative resections. About half the patients had had an abdominoperineal resection, half had had an anterior resection, and one third had had previous efforts to resect the recurrence. All but one patient had been irradiated with 3000-11,000 cGy. All but two patients (of the 24 curative efforts) required a formal abdominosacral resection (through S1-2 in 12, S2-3 in 9, and S4-5 in 1). Over half the patients also required a bladder resection. There were three operative deaths (12%); one patient had a cardiac death immediately after operation and two were septic deaths at 35 and 60 days. The survivors generally had relief of sacral root pain and good motor function; most of those previously employed could return to work. The actuarial 5-year survival rate is 25% and median survival is 36 months. Long-term survival over 48 months was recorded in five of 21 surgical survivors (23.8%). Survival in a historic comparative group of 30 patients treated for local recurrence only (mainly by radiation) was 15 months median, and at 5 years the survival rate was 3% (p less than 0.001). In conclusion, selected patients with pelvic recurrence of rectal cancer may be retrieved by and returned to functional life with the composite abdominosacral resection.

vascular Anomalies: Hemangiomas

Mulliken and Glowacki categorized vascular anomalies as either hemangiomas or malformations, with the former being the most common tumor of infancy. Despite distinct clinical, radiologic, and histologic findings, the two major types of vascular lesions are often confused. This complicates both patient care and interpretation of the medical literature. A thorough understanding of the presentation, natural history, treatment, and complications of vascular tumors (hemangiomas) and vascular malformations is essential to their proper management. A comprehensive review outlining the diagnosis and treatment of hemangiomas in presented.

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.

Principles of emergency wound management

Every traumatic wound treated in the emergency department is a result of a finite energy source that caused tissue disruption. The dynamics of this exchange of energy will determine the magnitude of injury. Disruption of the body covering leaves the once-sterile underlying integument exposed to contamination. The contaminants are derived from either the victim (endogenous) or the exogenous energy source. The presence of a contaminant such as bacteria makes the care of the wound an exercise in microbiology. Other contaminants, such as dirt, also may reside in the recesses of the wound. Emergency physicians must understand the consequences of tissue trauma. A study of the mechanism of injury will provide a reliable indication of damages. Whether the tissue injury will be limited to the initial wounding depends on the outcome of the interaction between the contaminants and the wound. In the event that the contaminants are very reactive, a relatively insignificant wound may become a catastrophe. This circumstance can be averted by the implementation of a well-devised plan based on the biology of wound healing and infection.

Galeal-pericranial flaps in head and neck reconstruction anatomy and application

Head and neck deformities of congenital, traumatic, or neoplastic cause often require reconstruction. At the University of Virginia over the past 14 years, we have used galeal, temporalis fascial, and pericranial flaps to correct these defects in more than 150 patients. Dissection of these flaps on both cadavers and reconstructive patients had demonstrated new anatomic findings different from those reported in standard textbooks. The galea is the most superficial layer of fascia. The pericranium is the next tissue layer. It is continuous above and separate from the temporalis muscle fascia. We may, therefore, consider three separate fascial layers for reconstruction. A rich vascular plexus arises from branches of the external and internal carotid arteries. Blood flow is axial to the galea and temporalis fascia. Pericranium has a dual supply from peripheral axial vessels and from perforating vessels from the overlying galea. Galeal, temporalis fascial, and pericranial flaps are reliable, thin, and supple and have a good arc of rotation and minimal donor site morbidity. They may be used to cover bone, cartilage, or implants, may be folded for bulk, may be used to carry blood to poorly vascularized recipient sites, or may be used to nourish bone, cartilage, skin, and mucosal grafts. Their versatility permits a wide variety of potential applications in head and neck surgery.

Bioengineering principles of hydrotherapy.

Hydrotherapy is based on several important bioengineering principles that permit the design and development of aquatic exercise devices, techniques and programs. These principles involve several forces (buoyancy, drag, inertia), hydrostatic pressure and the specific heat of water. By acquiring a knowledge of these bioengineering principles, an individualized exercise program can be prescribed that will enhance physical fitness which is associated with desirable psychological changes.

Head and neck surgery in the aged

This study was carried out to determine the perioperative mortality rate of patients over the age of 65 years who are undergoing major head and neck resections under general anesthesia. The total number of patients was 810 and the perioperative mortality rate (death within 30 days of operation) was 3.5 percent (29 of 810). This rate is relatively low when compared with the rate for patients undergoing similar procedures during the same period in the 35 to 65 years age group. Since 1975 reports of other types of surgery in the elderly have given perioperative mortality rates of from 4.8 to 26 percent. Previous studies of head and neck surgery in the elderly have given perioperative mortality rates of from 1.3 to 13.6 percent. Head and neck surgery in the elderly continues to be a safe procedure when compared with other types of surgery. As the portion of patients in the population over the age of 65 continues to increase, advanced age alone should not be a deterrent to performing aggressive surgical therapy for head and neck cancer.

Bacteriologic evaluation of electric clippers for surgical hair removal

Clipper blade assemblies for electric clippers used repeatedly without sterilization demonstrated high levels of bacterial contaminations that are potential sources of infection. A technique of sterilization of the clipper blade has been reported that eliminates the exogenous bacterial contamination.