Virtual reality simulator training of laparoscopic cholecystectomies - a systematic review.

BACKGROUND AND AIMS: Simulators are widely used in occupations where practice in authentic environments would involve high human or economic risks. Surgical procedures can be simulated by increasingly complex and expensive techniques. This review gives an update on computer-based virtual reality (VR) simulators in training for laparoscopic cholecystectomies. MATERIALS AND METHODS: From leading databases (Medline, Cochrane, Embase), randomised or controlled trials and the latest systematic reviews were systematically searched and reviewed. Twelve randomised trials involving simulators were identified and analysed, as well as four controlled studies. Furthermore, seven studies comparing black boxes and simulators were included. RESULTS: The results indicated any kind of simulator training (black box, VR) to be beneficial at novice level. After VR training, novice surgeons seemed to be able to perform their first live cholecystectomies with fewer errors, and in one trial the positive effect remained during the first ten cholecystectomies. No clinical follow-up data were found. Optimal learning requires skills training to be conducted as part of a systematic training program. No data on the cost-benefit of simulators were found, the price of a VR simulator begins at EUR 60 000. CONCLUSIONS: Theoretical background to learning and limited research data support the use of simulators in the early phases of surgical training. The cost of buying and using simulators is justified if the risk of injuries and complications to patients can be reduced. Developing surgical skills requires repeated training. In order to achieve optimal learning a validated training program is needed.

Intraoperative ultrasound as an aid to surgical strategy in liver tumor.

Ultrasonography of the liver was performed on 27 patients during laparotomy for liver lesions--11 primary and 13 metastatic mainly colon/rectum malignancies, and three benign conditions. Supplementary information on the liver parenchyma was provided in 11 cases (41%) in which the surgical strategy was decided simply by inspection and palpation of the liver. Ultrasound was most valuable for visualizing the vascular anatomy of the liver, giving clarification in 18 cases (66%), especially the relationship of tumor to portal and hepatic veins. This was decisive for the surgical strategy in four cases, enabling resection in two and modifying planned procedure in two. In a case of polycystic liver, ultrasonography imaged deep-lying cysts and aided the fenestration procedure. Liver resection was performed in 16 cases without operative mortality. Hepatic ultrasonography is useful for determining tumor spread, but of even greater value for the determination of strategy by clarifying tumor/vascular anatomic relationships.

Peroperative nitrous oxide delays bowel function after colonic surgery.

Forty patients scheduled for elective colonic surgery were allocated at random to receive either nitrous oxide or air during surgery. Preoperative management, surgery, parenteral therapy and postoperative analgesics were similar in both groups. Anaesthetic management included isoflurane, vecuronium by infusion and fentanyl 3 micrograms kg-1 h-1. The air group required a mean inspired isoflurane concentration of 0.8% (SD 0.3), whereas the nitrous oxide group required 0.4% (SD 0.2). No differences were found in duration of operation, blood loss, need for postoperative analgesia or postoperative nausea. Patients in the air group had less gas in the small bowel (P less than 0.005) and in the large bowel (P less than 0.001), and operating conditions were better than in the nitrous oxide group (P less than 0.01). After operation, the air group had significantly earlier bowel function than the nitrous oxide group, with earlier passing of flatus (3.4 (1.2) vs 4.7 (1.4) days) (P less than 0.05) and faeces (4.7 (1.5) vs 6.3 (2.2) days) (P less than 0.05) and required a shorter postoperative hospital stay (10.0 (1.3) vs 11.7 (2.5) days) (P less than 0.05).

Significance of ionized calcium during liver transplantation.

In liver transplant patients low plasma protein, acid base abnormalities and high citrate concentrations in the blood affects the binding of ionized calcium. In the present study plasma ionized calcium as well as serum total plasma calcium were measured in ten patients undergoing liver transplantation because of end-stage liver failure. During the operation, ionized calcium fell to as low as 0.46 mmol/l although calcium chloride was administered frequently at doses of 10 mg/kg. Serum total calcium concentration values did not fall but rose well above normal at the end of the operation. The measuring of total serum calcium may thus be dangerously misleading in patients undergoing liver transplantation.

Fine-needle aspiration biopsy in the monitoring of liver allografts. II. Applications to human liver allografts.

Serial fine-needle aspiration biopsies (FNAB) were used for clinical monitoring of human liver allografts. Nine liver allograft recipients were monitored with FNAB at 1-3 day intervals. No complications were recorded. All patients underwent at least 1 inflammatory episode of acute rejection; altogether 11 episodes, all reversible, were recorded. The inflammatory infiltrate consisted mainly of lymphoid cells, including lymphoid blasts, with minor involvement of monocytes, monoblasts, and macrophages. Further analysis of lymphoid cell subpopulations by immunoperoxidase techniques demonstrated an increase of T cells during rejection, both the CD4 (T4) and CD8 (T8) subsets were increased. A slight increase of B cells in the graft was also seen. The CD4/CD8 (T4/T8) ratio was first low, peaked at the onset, and decreased toward the end of the episode. No clear correlations to the intragraft cellular events were recorded in corresponding blood specimens. However, an episode of eosinophilia was seen in the blood at the beginning of rejection, correlating with fever in the recipient. Degenerative changes in the parenchymal cells and bile droplets in the hepatocytes, indicating cholestasis and hepatocyte damage, were seen during all episodes of rejection, and these changes persisted even 10 days after the inflammation had subsided. The FNAB-findings correlated well with biochemical laboratory parameters, but the diagnosis of rejection could be established by the FNAB already 1-5 days earlier than elevated serum values indicated liver dysfunction.

Non-invasive characterisation of angiopathy in the diabetic foot.

A comparison between 19 consecutive insulin dependent diabetic patients with a history of or current foot ulcers, gangrene or infection, with 14 arteriosclerotic patients with advanced lower limb ischaemia was performed using measurements of ankle and great toe systolic blood pressure, forefoot skin perfusion pressure and pulse volume assessment. Although clinical examination was usually sufficient to distinguish different types of diabetic foot, the vascular laboratory often gave additional information about the vascular component of the diabetic foot. In this study, great toe systolic pressure appeared to be the best indicator of the degree of macroangiopathy. The role of microangiopathy in the development of diabetic foot remains uncertain. The major factor responsible for diabetic foot in addition to neuropathy seems to be macroangiopathy which is not different from that of arteriosclerotic occlusive disease.

Late results and prognosis after carotid artery surgery.

Carotid reconstruction was performed on 75 patients (84 operations) mainly because of transient ischemic attacks (TIA) and/or amaurosis fugax (67%) or TIA with incomplete recovery (20%). The operative mortality was 2.4%. The incidence of permanent postoperative neurologic deficit was 6.0%. The postoperative observation time was 1 year to 13 years 5 months (mean 66 months). At follow-up 87% of the survivors were symptom-free. Three new strokes, one of them not related to the operated side, occurred follow-up, and 26 more patients died. The relative cumulative 5-year survival was 87.3%. Of the total 28 deaths, 16 were due to myocardial infarction. Mortality was significantly heightened and cumulative 5-year survival reduced when preoperative ECG had indicated coronary heart disease. The high incidence of deaths from myocardial disease during long-term follow-up was directly related to preoperative presence of coronary heart disease.

The prognostic significance of radiologically determined gastric emptying time before proximal gastric vagotomy.

The importance of undisturbed pyloric function is known among surgeons applying proximal gastric vagotomy (PGV) for duodenal ulcer disease. On the other hand, the prognostic significance of subclinically impaired antroduodenal motility is unknown after this operation. Therefore, in the present study 43 PGV patients with normal gastric emptying were compared with 24 PGV patients with prolonged gastric emptying as to the postoperative incidence of ulcer recurrence and symptomatology. Prior to surgery gastric emptying time was determined radiologically in all patients, none of whom had symptoms or signs of gastric outlet obstruction. The duration of postoperative follow-up in the series was 8 to 11 years. The incidence of ulcer recurrence during follow-up was 16% in the whole series, being significantly higher among patients with the primary ulcer in the pyloric or prepyloric area than among those with the lesion in the duodenal bulb. Furthermore, in the patient group with a primary ulcer in the duodenum an excellent operation result was achieved significantly more frequently in the case of preoperatively normal gastric emptying than in the case of delayed emptying. The incidence of ulcer recurrence tended also to be higher among the duodenal ulcer patients with prolonged emptying than among those with normal emptying through the difference between the groups did not reach statistical significance. This study emphasizes the prognostic significance of unimpaired gastric emptying and of even minor subclinical motor dysfunction when electing PGV as the surgical treatment and also that radiologic determination of gastric emptying time before PGV is of value in all patients undergoing the operation, irrespective of the location of the primary ulcer.

Tumour-associated trypsin inhibitor, TATI, in patients with pancreatic cancer, pancreatitis and benign biliary diseases.

The serum and urine concentrations of a tumour-associated trypsin inhibitor, TATI, were determined by radioimmunoassay in patients with pancreatic cancer and with benign pancreatic and biliary diseases. Elevated serum levels (greater than 20 micrograms l-1) were found in 85% of the patients with pancreatic cancer, and elevated urine levels (greater than 50 micrograms g-1 creatinine) in 96% of the patients. Thus low TATI level, especially in urine, makes the possibility of pancreatic cancer less likely. Serial assay of TATI in serum from three patients with surgically removed pancreatic cancer showed elevation of the TATI level at the time of detection of recurrence. However, high serum and urine levels were also seen in pancreatitis and in benign extrahepatic cholestasis. Thus TATI is a sensitive, although not specific, indicator of pancreatic and biliary disease, but the use of TATI as a tumour marker in the primary diagnosis of pancreatic cancer is limited. Immunohistochemical staining of pancreatic lesions showed that half of the pancreatic tumours expressed TATI, but the pancreatic tissue adjacent to a carcinoma always stained stronger than the carcinoma. It therefore seems that the main source of TATI in serum and urine of patients with pancreatic cancer are the normal acini and not the tumour tissue. In pancreatitis the staining was intense and clearly stronger than in normal pancreas.

The desmoid syndrome. New aspects in the cause, pathogenesis and treatment of the desmoid tumor.

Based on a detailed clinical and laboratory investigation of 89 patients with histologically verified desmoid tumor and the pertinent medical literature, we have reviewed the etiologic factors, clinical characteristics, and results of treatment of this rare disorder. The incidence of the tumor in the Finnish population is low, 2.4 to 4.3 new cases per 10(6) inhabitants per year. The age distribution profile demonstrated four distinct peak periods: the juvenile period, the fertile period, the middle-age period and the old-age period. The juvenile desmoid tumor is an extraabdominal tumor found in young girls, the fertile variety is an abdominal tumor found in women, the middle age variety is also overwhelmingly abdominal but the sex ratio approaches equality, whereas in the old age group, both abdominal and extraabdominal tumors are equally frequent and the sex ratio is equal. In all male patients, the growth rate was low. A low growth rate was also recorded in young girls. A growth rate of twice that speed was seen in fertile women and four times that speed in the middle age group. In the old age group, a low growth rate, equal to that of male patients, was a rule. The fertile female patients with desmoid tumor had a significant predisposition to estrogen dominance and deviation from progesterone dominance. The direct relationship of the growth rate to the level of endogenous estrogen in the female patients and the demonstration of significant amounts of estradiol but not progesterone receptors in the tumor cytosol further suggest that the growth rate of desmoid tumor is regulated by steroid sex hormones. A significant number of patients with an abdominal desmoid tumor had a history of surgical trauma in the region of subsequent tumor growth. A very high number of the patients demonstrated multiple minor malformations of the bony skeleton. An increased frequency of these malformations was also recorded in the families of the patients and the distribution of the malformations among the family members was compatible with an autosomally dominant pattern of inheritance. After operation, the frequency of recurrence was not statistically different, regardless of whether the tumor was completely removed or not. A combination of operation and radiotherapy did not reduce the frequency of recurrences; in fact, it doubled it.(ABSTRACT TRUNCATED AT 400 WORDS)

Evaluation of CA 19-9 as a serum tumour marker in pancreatic cancer.

Serum concentrations of the CA 19-9 antigen were determined in 91 patients with pancreatic cancer and in 111 patients with benign pancreatic, biliary and hepatocellular diseases. The CA 19-9 concentration was above the cut-off limit (37 U ml-1) in 78% of the patients with pancreatic cancer and high levels (greater than 500 U ml-1) were seen in 56% of these patients. Elevated levels were also seen in benign diseases (22%), especially in patients with extrahepatic cholestasis (up to 440 U ml-1). Hepatocellular jaundice and pancreatitis were associated with normal values (84% of the patients), or with only slightly elevated CA 19-9 levels (up to 88 U ml-1). The CA 19-9 test can be useful as an additional diagnostic tool for the detection of pancreatic cancer. Preliminary results suggest that the CA 19-9 assay can be used in the monitoring of surgically treated patients.

Malignant transformation in human colorectal mucosa as monitored by distribution of laminin, a basement membrane glycoprotein.

The distribution of laminin, a basement membrane glycoprotein, was studied by indirect immunofluorescence technique using rabbit anti-laminin serum in fifty-seven samples of normal, hyperplastic, adenomatous and carcinomatous colorectal tissue. As judged by the expression of laminin normal, hyperplastic and adenomatous colorectal mucosa were characterized by a continuous, linear basement membrane. A thick band-like basement membrane was seen under the surface epithelium and at the mouths of the crypts in normal and hyperplastic mucosa. The adenomatous epithelium was uniformly characterized by a thin, linear basement membrane. In contrast, marked alterations were constantly observed in colorectal carcinomas and their metastases, which showed a discontinuous, linear or patchy basement membrane. Our study suggests that the expression of laminin is related to cellular differentiation, and the thickness of the laminin-positive basement membrane parallels with the epithelial maturation of normal and hyperplastic colorectal mucosa and with the failure of the epithelial differentiation in adenomas. In colorectal carcinomas and their metastases the distribution of laminin is constantly altered and the severity of the alterations correlates with the histological grade of these tumours.