Skill performance in open videoscopic surgery.

INTRODUCTION: Application of minimally invasive surgery represents the future of modern surgical care. Previous studies by our group provided a novel way for viewing open surgery using a rigid endoscope attached to charged coupled device (CCD) camera in proximity to the surgical field using a robotic arm (AESOP) and a stabilizing fulcrum (Alpha port). MATERIALS AND METHODS: This study is a follow-up to investigate the technical feasibility, advantages, and disadvantages of relying only on video images displayed on standard monitors in performing open surgical procedures instead of direct binocular eye vision. This study used two surgeons as participants with training in basic surgical skill and previous experience in performing an intestinal anastomosis in an ordinary fashion. The standard task consisted of anastomosing porcine intestine in two layers with digital viewing of the operative field. A total of 40 anastomoses (20 by each surgeon) were compared with 10 control performances using direct vision of the field. RESULTS: All the resulting anastomoses were accurate, well coapted, and fully patent with no leakage. Time for task performance was approximately twice as long (p < 0.05) with videoscopic vision as with direct vision. DISCUSSION: These findings suggest it is technically feasible to conduct open surgeries with visualization of the open surgical field limited to video display on standard monitors.

Telementoring versus on-site mentoring in virtual reality-based surgical training.

BACKGROUND: Telementoring can be an adjunct to surgical training using virtual reality surgical simulation. Telementoring is hypothesized to be as effective as a local mentor for surgical skills training. METHODS: In this study, 20 Romanian medical students trained using a virtual reality surgical simulator (LapSim) with a telementor or local mentor. All the students watched an instructional module at the beginning of the exercise. The telementor, in the United States, interacted by videoconferencing. Before and after training sessions, tool path length and time for task completion were measured. RESULTS: Instructional media and training with mentoring resulted in similar levels of performance between locally mentored and telementored groups. Right- and left-hand path length and time decreased significantly within each group from the initial to the final evaluation (p < 0.05) for most tasks (grasping, cutting, suturing). No significant difference was achieved for clip-applying. CONCLUSIONS: Integration of instructional media with telementoring can be as effective for the development of surgical skills as local mentoring.

Preparation of viable islet cells from dogs by a new method.

A new method for the preparation of viable islet cells from the normal dog pancreas is described, based on the perfusion of the pancreatic duct with collagenase. Exposure of the acinar tissue to the highest concentrations of collagenase results in improved islet yield with decreased acinar contamination. After the selective digestion of the gland by ductal perfusion, mechanical dissociation liberates single cells and clumps. Analysis of the procedure by insulin yield and amylase attrition indicates a 57% B-cell recovery and a sixfold enrichment in B-cell concentration. The cells have been transplanted as autografts into dogs after pancreatectomy. In 5 of 7 transplanted dogs, normoglycemia was achieved postoperatively.

Allotransplantation of islet endocrine aggregates.

Dissociated pancreatic islets form endocrine aggregates from single-cell suspension by rotation culture. Islet cell aggregates, or neoislets, can provide endocrine reconstitution for diabetic rats and enjoy prolonged graft survival when neoislets are transplanted across a major histocompatibility barrier (Lewis to ACI). Long-term survival of grafted neoislets was obtained in 71% of recipients without any immunosuppression and in 100% of recipients with minimal immunosuppression. As predicted by cell-cell recognition in rotation-mediated aggregation, neoislets apparently exclude mesenchymal cells that bear la antigens. Therefore, reduced immunogenicity is accomplished.

Structure, function, and immune properties of reassociated islet cells.

Rat islets were mechanically dissociated to single cells and allowed to form aggregates by rotation-mediated cell-cell interaction. The aggregates, or neoislets, demonstrated insulin release in response to 20 mM glucose and 10 mM theophylline that was comparable to that of intact islets cultured for a similar time. However, basal insulin release was considerably greater than that from freshly isolated islets. The microscopic structure of the neoislets revealed sorting into a B-cell domain at the surface with A-cells interior to the aggregate. The neoislets generated no mitogenic response in allogeneic lymph node lymphocytes. Reassociation of single islet cells provides stable, functional endocrine units with substantial reduction of immunogenicity.

Isolating the elusive islet.

The lack of a technique that allows mass isolation of intact, viable human islets is part of the reason that islet transplantation has not become available to the human diabetic. This report outlines the history of islet isolation and presents two new technical modifications that have been developed in the dog. Many of the current problems in islet isolation are presented, including the difficulty in obtaining enough human pancreatic tissue with minimal warm-ischemia time; inadequate distention of the pancreas to provide sufficient disruption for maximal enzymatic reaction to release intact islets; inefficient chopping methods; the use of collagenase of variable composition; different digestion methods for obtaining isolated islets; and inefficient methods for separating and purifying the islets from the ductal, acinar, and fibrous components. The first new modification involves distention of the dog pancreas through the venous system of the gland rather than the ductal system. This results in improved intralobular disruption, which improved the yield of isolated dog islets by permitting more efficient collagenase digestion. The second new modification eliminates the concept of isolating intact islets: the dog pancreas is digested by trypsin to a single-cell preparation that is partially purified by Ficoll gradients; further purification of the endocrine cells results from selective aggregation using rotational culture. This process produces pseudoislets that contain all the islet cell types and can be kept in culture for up to 4 wk, releasing their hormones in response to appropriate stimuli. These modifications may assist in the struggle to isolate the elusive human islet for safe and effective islet transplantation in the diabetic patient.

Suppression, stress, and accommodation of transplanted islets of Langerhans.

Successful intrasplenic islet autotransplantation in dogs requires an islet cell mass considerably greater than what might be expected based on studies of subtotal pancreatectomy. Grafts of marginal function ultimately fail, suggesting severe limitations in the capacity of an islet graft to adapt. Accommodation was tested in established intrasplenic grafts by either chronically stressing the graft with mild carbohydrate intolerance induced by exogenous corticosteroids or chronically suppressing the graft with exogenous insulin. After these manipulations, insulin output into the portal vein in response to intravenous (i.v.) glucose was measured and compared with that of normal dogs and dogs receiving islet autografts with no further treatment with either steroids or insulin. Transplanted islets tolerated the two manipulations well in that neither exogenous steroid nor insulin led to failure of the graft as a consequence of either stress or protracted diminished demand. The major determinant of successful islet grafting is the endocrine competence of the initial graft. If that competence is provided at the outset, the graft can adapt to a considerable range of demand for insulin secretion.

Reversal of postoperative anuria by decompressive celiotomy.

Postoperative oliguria or anuria can rarely be attributed to an increase in intra-abdominal pressure. In this documented case, postoperative anuria responded to reduction in abdominal pressure by celiotomy. Actual abdominal pressure measurements are not available but probably would not be useful. However, hemodynamic measurements that were not consistent with diminished renal blood flow in a middle-aged patient were nevertheless associated with anuria, which responded to release of the abdominal pressure. Because of the association of regional pressure and acute renal decompensation, release of abdominal tension should be considered as a therapeutic option when hemodynamic measurements cannot explain a rapid decline in urine production.

Inhibition of rat mixed lymphocyte pancreatic islet cultures with anti-Ia immunotoxin.

Studies reported here indicate that an anti-Ia immunotoxin can eliminate the allostimulatory subpopulation of cells present within the islets of Langerhans without damaging the hormone-secreting cells. Such studies made use of an in vitro correlate of transplantation rejection, the mixed lymphocyte islet cell (MLIC) reaction. Using the MLIC, it was demonstrated that an anti-Ia immunotoxin removed cells capable of stimulating the MLIC in a dose-dependent fashion without altering the hormone-secreting functions of the remaining cells when challenged with glucose and theophylline. These studies suggest the feasibility of using such anti-Ia immunotoxins in islet allograft transplantation models to circumvent problems inherent in complement-mediated cytotoxicity, a previously documented effective form of inducing islet allotransplantation tolerance.

Adrenal medullary disease in multiple endocrine neoplasia type 2. Appropriate management.

This article discusses screening for pheochromocytoma and timing of surgery, unilateral versus bilateral adrenalectomy. Anterior, posterior, and laparoscopic operative techniques are reviewed also.

Neural regulation of heterotopic islets of Langerhans.

The possibility of vagal reinnervation to intrasplenic islet grafts was examined by measuring portal insulin response to electric stimulation of the dorsal vagus nerve in autografted dogs. Grafted islets responded appropriately to an exogenous cholinergic agent given intravenously. However, no insulin secretory response could be observed in grafted dogs after vagal stimulation, which markedly increased portal insulin levels in control dogs. Therefore, intrasplenic islets are not under direct vagal control. At the basal state, normal oscillatory release of insulin was observed in the animals with grafts, suggesting that the mechanism of rhythmic basal insulin release is intrinsic to the islet of Langerhans with no regulatory input from the vagus nerve or any element of pancreatic structure.

Failure of canine islet allografts and autografts with cyclosporine.

Intrasplenic autotransplantation of islet fragments prepared by ductal perfusion constitutes a reproducible system for islet delivery to apancreatic dogs. The animals are normoglycemic from the time of grafting, and graft failure is rare. In this study, apancreatic dogs received islet autografts (controls), autografts plus oral cyclosporine, and allografts plus oral cyclosporine. Therapeutic blood levels of cyclosporine were documented by radioimmunoassay. However, allografts and autografts ceased to function after initial normoglycemia in all animals that received cyclosporine, and four out of six autografts failed. Normoglycemia persisted in the control-autografted animals for the duration of the study. Microscopic sections of the failed grafts demonstrated meager tissue survival but no evidence of rejection by cellular infiltration.

Nonfunctioning islet cell carcinoma of the pancreas.

BACKGROUND: Nonfunctioning islet cell carcinoma of the pancreas has a variable and often indolent natural history, which has resulted in a wide range of treatment recommendations. To more clearly define the natural history and appropriate treatment of this disease, we reviewed our institutional experience over the last 39 years. METHODS: The records of all patients confirmed to have a nonfunctioning islet cell carcinoma of the pancreas were retrospectively reviewed. Kaplan-Meier life tables were constructed and log-rank comparisons were performed. RESULTS: The 73 patients studied had an overall 5-year actuarial survival rate of 50%. Patients with localized disease at presentation (n = 39) had a significantly higher survival rate (p = 0.03) compared with patients with metastatic disease (n = 34). The 19 patients who underwent a potentially curative resection of the primary tumor had a significantly higher survival rate (p = 0.03) compared with the 20 patients with locally advanced, unresectable, nonmetastatic disease. Nine of these 20 patients died of complications of the primary tumor. In contrast, only 2 of 22 cancer-related deaths in the 34 patients with metastatic disease at diagnosis were due to the primary tumor. CONCLUSIONS: (1) Surgical resection should be performed in patients with resectable nonmetastatic disease. (2) Resection of the primary tumor in the presence of metastatic disease is rarely indicated. (3) Innovative treatment strategies are needed for patients with locally advanced, unresectable, nonmetastatic tumors of the pancreatic head.

Pseudoxanthoma elasticum and polyposis coli: a novel co-mutation.

Pseudoxanthoma elasticum and polyposis coli are inherited conditions not, to our knowledge, previously reported to coexist. The spontaneous appearance of both conditions in a 62-year-old woman may represent a novel mutation. The defective cell in both pseudoxanthoma and some of the extracolonic manifestations of Gardner's syndrome is the fibroblast; therefore, this case may represent a unique variation of Gardner's syndrome.

Gallbladder response to enteral lipids in injured patients.

Severely injured patients are at risk for complications of gallbladder stasis in a spectrum from sludge formation and cystic duct occlusion by inspissation and, subsequently, acalculous cholecystitis. In a double-blind randomized trial, the effect of enteral lipids on the ability of the gallbladder to clear itself was tested. The gallbladder was assessed by ultrasonography for acute contractions, sludge and dilatation on days 1, 3, and 7 after injury. There were no significant differences between patients who received enteral lipids and controls. Both groups showed modest enlargement of the gallbladder and failure of contraction. In a population at risk for biliary stasis following severe trauma, standard enteral lipids did not elicit, acutely or chronically, an appropriate reflexive evacuation of the gallbladder.

Mucormycosis in patients with multiple-organ failure.

Mucormycosis in two patients with multiple-organ failure appeared as a cutaneous lesion and spread rapidly. In the first case, wet mounts and potassium hydroxide preparations were unhelpful, but a punch biopsy specimen established the diagnosis. Prompt and extensive debridement and amphotericin B administration arrested the infection. In the second case, virulent progression of the lesion occurred despite limited amputation, debridement, transfer factor, and amphotericin B, but finally responded to further amputation. Diagnosis was made by histologic examination of infected tissue. Both patients shared the following predisposing factors: sepsis, low blood flow, acidosis, multiple-organ failure, and multiple-antibiotic therapy. Although the mucormycosis was controlled, as confirmed in the first case at autopsy and in the second case by clear margins following reamputation, the outcome was fatal in both cases due to other features of multiple-organ failure.

Lateral thoracotomy and one-lung anesthesia in patients with morbid obesity.

Between May, 1980, and October, 1981, 22 morbidly obese patients ranging in weight from 93.4 to 236.8 kg (average, 145.2 kg) underwent transthoracic gastric stapling. Fourteen of these operations were performed using endobronchial intubation and selective collapse of the left lung to facilitate surgical exposure. The patients were compared with 22 consecutive patients treated by trans-abdominal gastric stapling during the same period. None of the 44 patients had evidence of chronic alveolar hypoventilation (pickwickian syndrome). In terms of operating time, blood loss, duration of intubation, and hospital stay, the two groups did not differ significantly. Despite marked shunting during one-lung ventilation, satisfactory arterial oxygen tension (PaO2) could be demonstrated on 100% oxygen for all thoracotomy patients (PaO2 range, 67 to 230 torr; mean, 132.3 torr). In fact, except for a lower PaO2 during one-lung anesthesia, the thoracotomy patients were indistinguishable from the laparotomy patients in terms of perioperative respiratory function. Pain, sedation, and positioning led to significant decreases in vital capacity and one-second forced expiratory volume in both groups on the first post-operative day, and in the thoracotomy group on the second day. There were only two wound infections in the thoracotomy group, as opposed to six infections with two dehiscences in the laparotomy group. It is concluded that lateral thoracotomy with or without one-lung anesthesia can be performed safely in massively obese patients--at least in those without preexisting alveolar hypoventilation syndrome.

Association of p53, p16, and vascular endothelial growth factor protein expressions with the prognosis and metastasis of gallbladder cancer.

BACKGROUND: Tumor suppressor genes were studied in gallbladder disease including cancer for correlation. VEGF (vascular endothelial growth factor) expression was assessed against Nevin staging and metastasis of gallbladder carcinoma. The importance of p53, p16, and VEGF in gallbladder cancer was estimated. STUDY DESIGN: Twenty-four gallbladder carcinomas, 20 gallbladder adenomas, and 18 chronic cholecystitis specimens were immunohistochemically and histopathologically investigated for the relation of p53, p16, and VEGF to Nevin staging and pathologic grading. RESULTS: The expression rate of abnormal p53 in gallbladder carcinomas was significantly higher than that in gallbladder adenoma and chronic cholecystitis (p = 0.003, p = 0.014). The expression rate of abnormal p53 in Nevin staging S1, S2, S3 gallbladder carcinoma was significantly higher than that in S4, S5 (p = 0.01). Abnormal p16 was highest in carcinoma, next in adenoma, and lowest in chronic cholecystitis (p = 0.031, p = 0.017). Gallbladder carcinoma expressed VEGF far more often than adenoma or cholecystitis (p = 0.001); VEGF-positive rates were lower in S1, S2, S3 than S4, S5 by Nevin staging of gallbladder cancer (p = 0.044). CONCLUSION: Mutation of p53 and p16 genes might correlate with progression of of gallbladder carcinoma. Analysis of p53 and p16 can estimate the prognosis of gallbladder cancer. VEGF expression correlates with Nevin staging in gallbladder cancer.

The effect of diabetes mellitus on aortic prostanoid synthesis and serum cholesterol levels in the rat fed a high cholesterol diet.

The effect of diabetes mellitus on serum cholesterol and aortic microsomal prostanoid synthesis was studied in cholesterol fed male Lewis rats. Normal, diabetic and diabetic rats treated with pancreatic islets were divided into three diet subgroups, control diet, control +2% cholesterol for 8 weeks and control +2% cholesterol diet for 16 weeks. Serum glucose levels were elevated three-fold in the diabetic group compared to normal. Treatment with islets restored serum glucose to normal levels in diabetic rats. The 2% cholesterol diet did not significantly alter serum glucose levels in any of the groups. Body weights in the diabetic group were significantly lower than normal or diabetic rats treated with islets. Feeding 2% cholesterol for 16 weeks significantly increased weight in normal and islet treated diabetic rats but not in the diabetic group. Aortic microsomal prostanoid synthesis was similar in all experimental groups with 6-keto-PGF1 alpha (PGI2 metabolite) being the major product synthesized in all groups. Aortic microsomal prostanoid levels were not altered by the 2% cholesterol diet. Serum cholesterol levels increased 14-fold in the diabetic group which returned to the normal level in the diabetic animals treated with islets. These data show that diabetes does not alter aortic microsomal prostanoid levels in the rat. However, diabetes significantly increased serum cholesterol levels which were reversed by islet transplantation.

Osseous and chondral fixation of polypropylene mesh.

Fixation of polypropylene (Marlex) mesh in the epigastrium and at the iliac crest can be ineffective because of insufficient local fascia; however, two techniques have been described to obtain firm and durable attachment of polypropylene grafts at these sites. Perichondral slips at the costal margin permit very satisfactory attachment with excellent long-term results. Stainless steel wire fixation of the mesh to the iliac crest has satisfied the need for osseous fixation in that area. Long-term repair of difficult and recurrent hernias has been described in three patients for whom other tactics for abdominal wall repairs were not available.