Earl W. McAllister

The role of polymeric surface smoothness of biliary stents in bacterial adherence, biofilm deposition, and stent occlusion

Bacterial adherence and biofilm deposition onto the surface of polymers used for biliary stents are the initial events that ultimately lead to stent occlusion. Vivathane is a new polymer with an ultrasmooth surface. In this study, stents made from Vivathane were compared to standard plastic stents in an in vitro model. Polyethylene, C-flex, and Vivathane stents were connected in parallel and perfused with infected bile. The surfaces of the polyethylene and C-flex stents developed exuberant bacterial growth and biliary sludge deposition. Vivathane stents were nearly free of bacteria and demonstrated no propensity for biliary sludge deposition. These results indicate that polymeric surface irregularities promote bacterial adherence, biofilm deposition, and accumulation of biliary sludge. The ultrasmooth surface of Vivathane does not allow bacterial adherence and biofilm deposition. Vivathane holds promise as a new polymer for use in biliary stents in long-term applications.

Perineal reconstruction after surgical extirpation of pelvic malignancies using the transpelvic transverse rectus abdominal myocutaneous flap

AbstractBackground: The nonhealing perineal wound is often a catastrophic complication after aggressive surgical extirpation of pelvic malignancies. Methods: Eleven patients underwent perineal reconstruction using an inferiorly based transpelvic transverse rectus abdominal myocutaneous (TRAM) flap for large nonhealing postsurgical perineal wounds. After debridement of the perineum, the rectus muscles and their skin islands were mobilized, preserving their inferior epigastric blood supply. The flap was then taken through the midline abdominal incision transpelvically into the perineal defect. The study population was composed of three men and eight women ranging in age from 43 to 76 years (mean 59). The primary diagnosis was recurrent carcinoma of the rectum or anus (n=5), recurrent squamous cell carcinoma of the vulva or cervix (n=4), and recurrent sacral chordoma (n=2). All patients had received adjuvant radiation therapy and all patients had undergone one to four previous attempts at perineal closure. The perineal defect ranged in size from 72 cm2 to 1,250 cm2 (mean 337). Results: There were no perioperative deaths. Ten of the 11 patients (91%) had primary wound healing of the TRAM flap, perineal wound, and donor site. One patient with recurrent chordoma developed recurrent tumor at the suture line 4 months postoperatively. Conclusions: The inferiorly based transpelvic TRAM flap is a safe and effective reconstructive technique for recalcitrant nonhealing perineal wounds after extirpation of pelvic malignancies.

The acute surgical abdomen after cardiac surgery involving extracorporeal circulation.

From 1972 through 1984, 7140 cardiac operations were performed at one university teaching hospital; they were reviewed to elucidate common factors in patients developing an acute surgical abdomen after cardiac surgery and extracorporeal circulation. Twenty-one patients (0.29%) developed an acute surgical abdomen in the period following cardiac surgery. The abdominal surgical complications were, in general, due to complications of peptic ulcer disease, decreased intestinal blood flow, and cholecystitis. There was no correlation between preoperative history, physical examination, cardiac function, laboratory data, and the subsequent development of an acute abdomen. Mortality rate, 24% after abdominal surgery, was increased with emergency cardiac operations, combined cardiac procedures, complications of cardiac surgery, unnecessary delay of abdominal surgery, and abdominal wound complications. Major abdominal wound complications were seen in 38%. Patients undergoing cardiac surgery may develop a variety of common abdominal surgical disorders. Patients so inclined cannot be identified prior to cardiac surgery. Ulcer prophylaxis, wound management, prompt resuscitation, and timely surgery are critical.

Prospective study of a prosthetic H-graft portacaval shunt

This study was undertaken to prospectively evaluate the 8-mm Gore-Tex interposition H-graft portacaval shunt. Thirty-six high-risk patients at the University of South Florida-affiliated hospitals received small-diameter shunts because of bleeding esophagogastric varices over a recent 2-year period. Portal vein and portal vein-inferior vena cava gradients were significantly reduced after shunting. These pressure changes were manifested clinically by the absence of variceal rebleeding and improvement of ascites; in addition, the incidence of encephalopathy was low. The 8-mm graft maintained hepatopedal flow in 67% of the patients, but reversal of flow did not result in complications commonly associated with poor portal perfusion. Graft thrombosis occurred in four (11%) patients. All grafts were successfully revised, three by operative revision and one by an interventional radiologist. Operative mortality was low (11%), and morbidity was unusual. The small-diameter H-graft portacaval shunt is a safe and effective method of treatment for bleeding esophagogastric varices.

The Gastroileoileal Pouch: An Alternative Continent Urinary Reservoir for Patients with Short Bowel, Acidosis and/or Extensive Pelvic Radiation

We report on 6 patients who underwent a new type of continent urinary diversion: the gastroileoileal reservoir. These are a select group of patients who presented with the short bowel syndrome, acidosis, borderline diarrhea and/or severe pelvic radiation, which precluded the use of terminal ileum and the ileocecal segment. Considering these factors, and based on the different functional properties of the stomach as well as the need for a large reservoir, a segment of stomach and proximal ileum was used to construct the reservoir. Four patients have been followed for at least 6 months, with the longest followup being 12 months. Temporary dysphagia requiring hydrogen blockers developed in 1 patient. Results indicate excellent function of the continent urinary system, lack of metabolic complications, absent diarrhea and excellent patient tolerance. This procedure could be a useful alternative in some difficult clinical situations when continent urinary diversion is desirable.

Is Triple Contrast Computed Tomographic Scanning Useful In The Selective Management Of Stab Wounds To The Back

We devised a protocol to prospectively manage stab wounds to the back with the hypothesis that the triple contrast computed tomographic (CT) scan is an effective means of detecting occult injury in these patients. All wounds to the back in hemodynamically stable adults were locally explored. All patients with muscular fascial penetration underwent triple contrast CT scanning utilizing oral, rectal, and IV contrast. Patients did not undergo surgical exploration if their CT scan was interpreted as negative or if the CT scan demonstrated injuries not requiring surgical intervention. Fifty-three patients were entered into the protocol. The time to complete the triple contrast CT scan ranged from 3 to 6 hours at a cost of

Prolonged evaluation of epinephrine and normal saline solution injections in an acute ulcer model with a single bleeding artery

1050 for each scan. In 51 patients (96%), the CT scan either had negative findings (n = 31) or showed injuries not requiring exploration (n = 20). These patients did well with nonsurgical management. Two CT scans documented significant injury and led to surgical exploration and therapeutic celiotomies. Although triple contrast CT scanning was able to detect occult injury in patients with stab wounds to the back it did so at considerable cost and the results rarely altered clinical care. Therefore, its routine use in these patients is not recommended.

Postprandial augmentation of portal hepatic inflow after prosthetic h-graft portacaval shunt☆

BACKGROUND Animal studies of epinephrine or normal saline solution injection for bleeding ulcers do not consistently demonstrate local tamponade effect. METHODS We studied the change of bleeding rates of 28 acute gastric ulcers with a single bleeding artery in 10 dogs. Four injections of 1 mL epinephrine 1:10000 at 1 mm from the spurting artery (n = 7) were compared to four injections of normal saline solution 1 to 5 mL (n = 12) and to four dry needle sticks (n = 9). Bleeding rates were measured at initial arterial incision and at minutes 1, 5, 10, 15, 20, 25, and 30 after treatment. RESULT Reductions in early blood loss to 24.3% +/- .05 of baseline occurred with saline solution, to 17.7% +/- .03 with epinephrine, and to 66.0% +/- 1.8 in controls (p < .05 for epinephrine and saline solution vs control). A tendency for saline solution injected ulcers to resume bleeding was identified, with late blood loss increasing to 26.9% +/- .05 of baseline, (saline solution vs control) compared to 7.7% +/- .02 in epinephrine injected ulcers (p < .05 vs control). CONCLUSIONS The early acute hemostatic effect of injection therapy depends on local tamponade. The prolonged hemostatic effect is a combination of tamponade and vasoconstriction, with advantage of epinephrine over saline solution.

Direction or reversal of preshunt portal blood flow as determinants of outcome up to 1 year after small-diameter prosthetic H-graft portacaval shunt.

Encephalopathy after portasystemic shunting generally occurs after eating. After partial portal decompression, encephalopathy is uncommon, presumably because of associated portal hemodynamics. However, after partial shunting, the changes in portal venous hemodynamics that occur with eating are unknown. With this in mind, 11 nonencephalopathic adults were studied more than 1 year after 8-mm H-graft portacaval shunt (PCS). The studies utilized color flow duplex ultrasound to determine the changes in portal vein (PV) and inferior vena cava blood flow that occur with eating a standardized meal. Following H-graft PCS, there is increased blood flow in the inferior vena cava after eating, particularly cephalad to the H-graft PCS, implying increased flow through the prosthetic shunt. Eating also increases hepatopedal blood flow in the PV distal to the H-graft PCS. Postprandial increases in hepatopedal portal blood flow may play an important role in avoiding encephalopathy after H-graft PCS.