PubMed Health⌕ Search

Biomedical subjects

A Cuschieri

Publications and source records attributed to A Cuschieri.

At least 19 recordsLinked to original sources
PubMed2007

Artificial neural network: predicted vs observed survival in patients with colonic cancer.

PURPOSE: An Internet-web-based artificial neural network has been developed for practicing clinical oncologists and medical researchers as part of an ongoing program designed for the implementation of advanced neural networks for prognostic estimates and eventually for management/treatment decisions in individual patients with colonic cancer. METHODS: An interdisciplinary team of academic oncologists and physicists has configured and implemented a Partial Logistic Artificial Neural Network and trained it to predict cancer-related survival in patients with confirmed colorectal cancer by using a database (1,558 patients) made available for the study by the Information & Statistics Division of National Health Service Scotland. The reliability of the trained network was evaluated against Kaplan-Meier observed survival plots of a random sample of 300 patients not used in the training but forming part of the same data set. RESULTS: The predicted survival curves obtained as the output from the artificial neural network showed close agreement with observed actual survival rates of a cohort of 300 patients with four grades of risk of dying from the cancer within five years of diagnosis. CONCLUSIONS: The web-based Partial Logistic Artificial Neural Network system accurately predicts survival after staging and treatment of colonic cancer. It can be made web-accessible where it is powerful enough to serve hundreds of users simultaneously.

Aged↗
PubMed2006

Mechanical properties of the human abdominal wall measured in vivo during insufflation for laparoscopic surgery.

BACKGROUND: Carbon dioxide insufflation of the peritoneal cavity for laparoscopic surgery offers a unique opportunity to measure some mechanical properties of the human abdominal wall that hitherto have been difficult to obtain. METHODS: The movement and change of the abdominal wall during insufflation to a pressure of 12 mmHg was studied in 18 patients undergoing laparoscopic surgery using a remote motion analysis system that does not compromise the sterility of the operative filed. These data together with the known abdominal wall thickness of each patient (measured by preoperative ultrasound scanning) enabled estimates of mechanical stiffness. RESULTS: The findings showed that the abdominal wall changes from a cylinder to a dome during inflation, and that its area is increased by 15%. A volume, averaging 1.27 x 10(-3)m(3), results from expansion, reshaping of the abdominal wall, and displacement of the diaphragm. The abdominal wall is stiffer in the transverse plane than in the sagittal plane (Young's modulus, 42.5 +/- 9.0 kPa vs 22.5 +/- 2.6 kPa; p = 0.03; paired t-test). CONCLUSIONS: Measurements of mechanical properties of the abdominal wall in patients undergoing laparoscopic surgery were obtained using a remote motion analysis system.

Abdominal Wall↗
PubMed2006

Epistemology of visual imaging in endoscopic surgery.

Little work has been done on aspects of visual perception and related defects as they affect the proficiency level for endoscopic surgery, in which the surgeon must operate from images rather than reality (indirect perception). Newer metrics of image quality should be used to assess image displays for endoscopic surgery because they provide more objective data. Ergonomic considerations relating to operations from images have likewise been inadequately researched. The monitor optimal working distance is highly variable from surgeon to surgeon. This problem could be overcome easily by the use of floor markings. Data from visual ergonomic experimental studies indicate that the best performance in endoscopic surgery is obtained by frontal gaze-down viewing because this restores the alignment of the visual with the motor axes of the operator.

Attention↗
PubMed2006

Competence assessment of laparoscopic operative and cognitive skills: Objective Structured Clinical Examination (OSCE) or Observational Clinical Human Reliability Assessment (OCHRA).

BACKGROUND: There is no agreed system that is acknowledged as the ideal assessment of laparoscopic operative and cognitive skills. A new approach that combines Objective Structured Clinical Examination (OSCE) and Observational Clinical Human Reliability Assessment (OCHRA) was developed and used to assess trainees' operative and cognitive skills during laparoscopic training courses. METHODS: Performance of 60 trainees participating in 3-day essential laparoscopic skills training (cognitive and psychomotor) courses were assessed and scored using both OSCE and OCHRA. RESULTS: The study showed significant inverse correlations between the number of technical errors identified by OCHRA and the scores obtained by OSCE for individual tasks performed either by electro-surgical hook or laparoscopic scissors (r = -0.864 and r = -0.808, respectively). Significant differences between trainees were observed in relation to both overall OSCE scores and OCHRA parameters: execution time, total errors, and consequential errors (P < 0.001). CONCLUSIONS: OCHRA provides a discriminative feedback assessment of laparoscopic operative skills. OCHRA and OSCE are best regarded as complementary assessment tools for operative and cognitive skills. The present study has documented significant variance between surgical trainees in the acquisition of both cognitive and operative skills.

Cholecystectomy, Laparoscopic↗
PubMed2006

Optimum view distance for laparoscopic surgery.

BACKGROUND: Proper visualization of the surgical field without fatigue is essential in laparoscopic surgery and reduces the risk of iatrogenic injuries. One of the important factors influencing visualization is the viewing distance between the surgeon and the monitor. This was the subject of the current investigation. METHODS: For this study, 14 surgeons participated in experiments designed to determine two working distances from a standard 34-cm (14 in. diagonal) cathode ray tube (CRT) monitor: (a) the maximum view distance permitting small prints of a near vision chart to be identified clearly by sight, (b) and the minimum view distance (of a standard resolution chart) just short of flicker, image degradation, or both. The range of the monitor optimal working distance for laparoscopic surgery was extrapolated from these data sets. RESULTS: The maximum view distance allowing identification of detail averaged 221 cm (range, 166-302 cm). The mean minimal view distance short of flicker/image degradation was 136 cm (range, 102-168 cm). The coefficient of variation for the two view distances was almost identical (18% vs 17%, respectively), and a frequency histogram confirmed the normality of the two data sets. Thus, for most surgeons, the extrapolated monitor view distances for laparoscopic surgery using a 14-in. diagonal (34-cm) monitor range from 139 to 303 cm (57-121 in.) for maximal distance viewing and from 90 to 182 cm (36-73 in.) for close-up viewing (i.e., a monitor optimal working distance ranging from 90 to 303 cm (36-121 in.). CONCLUSIONS: For most surgeons operating from a 14-in. diagonal CRT monitor, both the maximal and minimal (close-up) view distances are individually variable, but the surgeon should never be farther than 3 m (10 ft) or less than 0.9 m (3 ft) from the monitor. However, within limits, the maximal view distance increases with increasing monitor size. The limit for close-up distance is 0.9 m, irrespective of monitor size.

Clinical Competence↗
PubMed2006

Free radical production in the esophago-gastro-duodenal mucosa in response to acid and bile.

Several studies have demonstrated the role of free radicals in causing esophagus-gastro-duodenal mucosal injury. The present study has been designed to investigate: whether acid, bile salts and a combination of bile + acid could determine the production of O2-derived free radicals by oesophageal, gastric and duodenal mucosa; which agent is capable of producing more free radicals and if O2-derived free radicals production depends on the duration of contact with acid, bile salts and their combination. Wistar rats' gastro-intestinal mucosa were perfused with bile, acid and a combination of bile + acid at pH4 and pH2 for 1 hour and 2 hours. Free radical production (FRP) was assessed by chemoluminescence. After 1 hour, the increase in FRP in comparison with control reached statistical significance (P < 0.05) at all tested pH levels in the duodenum, at pH1, 2 and 3 in the esophagus, and at pH1 in the stomach. Comparing different segments, both the esophagus and duodenum behaved similarly, producing more free radicals than the stomach at all pH values. However, this difference reached statistical significance at pH1 and 2 only. In comparison to control, FRP was increased by bile (pH7) infusion after 1 and 2 hours. There was increased FRP in all segments after the infusion of bile at pH2 and 4 in comparison to control. Infusion of bile at pH2 stimulates more FRP than infusion of bile at pH4 in all segments. This increased FRP reaches statistical significance in the esophagus after 2 hours of infusion, in the stomach after 1 and 2 hours of infusion, but in the duodenum it does not reach statistical significance. Acid, bile and bile + acid at pH2 and 4 can cause free radical production in esophageal, gastric and duodenal mucosa. Their role in producing free radicals is different according to the segment and the chemical composition of the solution.

Animals↗
PubMed2005

Skin wound closure with a novel shape-memory alloy fixator.

BACKGROUND: Previously, we have described novel, thermally deployable tissue fixators based on the shape-memory properties of nickel titanium. The present study reports on the in vivo wound closure with these fixators as a preliminary to evaluating their use for bowel anastomoses. METHODS: Twenty adult Sprague-Dawley rats had 2.0-cm dorsal skin incisions approximated either with shape-memory alloy (SMA) fixators or conventional skin staples on a random basis. Electrical resistance heating was used to transform and deploy the SMA fixators into the wound. The rats were killed on day 14 or day 28 and wound specimens were harvested for force distraction studies and histologic examination. RESULTS: There was no incidence of wound dehiscence. 14- and 28-day wounds from both groups showed no significant difference in breaking force or energy. Histology revealed appropriate stages of wound healing for both SMA-closed and control wounds. CONCLUSIONS: The results confirm the efficacy and safety of tissue-edge approximation with SMA fixators.

Alloys↗
PubMed2005

Minimal access surgery (MAS)-related surgeon morbidity syndromes.

The benefits of minimal access surgery (MAS) in terms of accelerated recovery, reduced period of short-term disability, and patient outcome account for the widespread use of the laparoscopic approach by the majority of general surgeons. In adopting this approach with its current limitations and poor ergonomics, surgeons have been known to sustain surgery-related injuries encompassed by a spectrum best described as MAS-related surgeon morbidity syndromes, some of which are currently overlooked and poorly researched. Equivalent morbidities including the overuse syndrome (from overuse of certain muscle groups during long operations) have been documented in open surgery but are nowadays rare occurrences. As more advanced MAS operations are performed with long execution times, new patterns of neuromusculoskeletal injuries are being recognized. The surgical fatigue syndrome has also been described, though its complex nature is not fully understood. Virtually little is known on other long-term adverse effects on the surgeon following many years of operating from images displayed on a television monitor or LCD screen, and these include deterioration of visual acuity and function of the ocular muscles responsible for fixation-refixation of the eyeballs. The limited reported literature on the MAS-related surgeon morbidity syndromes identifies certain risk factors for these injuries pertaining to central and peripheral domains. Only improved knowledge of the etiology and underlying ergonomic factors based on investigative studies followed by improved instrumentation and operating room (OR) ergonomics will provide near- and long-term solutions.

Cumulative Trauma Disorders↗
PubMed2005

Reducing errors in the operating room: surgical proficiency and quality assurance of execution.

Technical operative errors cause surgical operative morbidity and adversely affect the clinical outcome of patients. Surgical proficiency thus underpins good and safe practice. In this context, standardization of endoscopic surgical operations and their execution are essential for the procurement and maintenance of quality assurance in endoscopic surgical practice. There is no clash between individual- (surgical proficiency) and system-based defense systems in the prevention of surgical errors--both underpin safe surgical practice. Although more human factors and surgical research are needed, it is possible to formulate and adopt a surgical error reduction system for endoscopic operations based on standardization of operations, surgical operative proficiency, and human reliability assessment and its related clinical counterpart, observational clinical human reliability assessment.

Clinical Competence↗
PubMed2005

Multimedia article. Laparoscopic transection choledochoduodenostomy.

Choledochoduodenostomy is a well-established procedure and is indicated in patients with multiple ductal calculi and dilated common bile duct (>or=2.0 cm) because these patients require drainage for good long-term results without recurrence of jaundice or cholangitis. The technique most commonly used is that of a side-to-side hand-sutured anastomosis between the supraduodenal common bile duct and the duodenum. The merit of this technique is its simplicity, although it is prone to duodenobiliary reflux and to occasional symptomatic inspissation with food debris causing cholangitis (sump syndrome). It is the technique that has been adopted by most centers for laparoscopic choledochoduodelaostomy. The alternative operation, transection choledochoduodenostomy, excludes the distal (transpancreatic) segment of the bile duct from the end-to-side anastomosis of the transected common bile duct with the second part of the duodenum. The long-term results of this procedure are excellent, and for this reason we have used it for laparoscopic drainage of the common bile duct in six elderly patients (four females and two males; age range, 61-72 years) with multiple occluding ductal calculi and grossly dilated bile duct. Three of these patients (including the one shown in the multimedia video) were admitted acutely with bacterial cholangitis and required emergency insertion of pigtail stent to overcome the acute septic illness. There were no conversions. The first operation lasted 4 h but the operating times in the last two patients were 2.0 and 2.5 h. The results have been excellent, with no deaths and a low postoperative morbidity (chest infection in one patient) and median postoperative hospital stay of 5 days.

Aged↗
PubMed2005

Analysis of errors enacted by surgical trainees during skills training courses.

BACKGROUND: Despite the emphasis on medical error as a major cause of hospital morbidity and mortality, there has been little published work on errors committed by trainees. This issue is particularly relevant to the training of surgeons and was addressed by our study. METHODS: Sixty simulated laparoscopic cholecystectomies performed on restructured pig tissue models by 60 surgical trainees provided the study material. The unedited videotapes were analyzed by observational HRA of the component steps of the procedures. Ten generic forms of observable error types were used to categorize patterns of failure. Error probabilities with specific instruments were also calculated. RESULTS: A total of 1067 errors were identified by observational HRA: 331 consequential and 736 without consequence (ie, total error rate of 18 [SD +/- 10]) per procedure. The study documented a wide variation in the number of errors between the 60 trainee surgeons. The important underlying factors for the trainee errors were (1) omission of important steps, (2) execution of steps in the wrong sequence, and (3) use of excessive force. These 3 errors accounted for 92% of consequential errors. CONCLUSIONS: This study has shown that trainees vary considerably in their propensity to commit errors. This variability indicates that the surgical training in component skills for laparoscopic surgery should be flexible and individualized. Three mechanisms account for the majority of errors and indicate that skills training in surgery has to be structured, menu driven, and tailored to individual needs.

Animals↗
PubMed2005

Laparoscopic surgery: current status, issues and future developments.

Laparoscopic surgery has come a long way since its introduction two decades ago. In essence it represents a new era of technology-dependent surgical interventions, and to some extent its future progress depends on the growth of interventional technologies and devices (facilitative, enabling and additive). Laparoscopic surgery has had a significant impact on all surgical disciplines and is now firmly embedded in routine surgical practice. There remain, however, several outstanding issues that need to be addressed. These concern mainly quality assurance, training, resource allocation, assessment of competence and tiers of laparoscopic surgical practice in line with the changing situation facing the next generation of surgeons.

Biomedical Technology↗
PubMed2005

Familial pseudoexfoliation in Gozo.

AIMS: To describe the occurrence of pseudoexfoliation in three Gozitan families. METHODS: Three families with a high incidence of pseudoexfoliation were identified. All members of the three families who agreed to participate were interviewed and underwent a full ophthalmologic examination. The pseudoexfoliation status was classified as present, absent, or unknown. RESULTS: A total of 55 individuals from three separate family probands and with a male : female sex ratio of 5 : 4 were examined. In all, 18 had definite evidence of pseudoexfoliation, 17 of them bilaterally and one showing only unilateral signs. Age was the main risk factor, with 18 out of the 20 individuals who were over the age of 60 years having pseudoexfoliation, while none of the 35 who were below the age of 60 years had pseudoexfoliation. The ophthalmological findings varied in different families. Family I had a high incidence of both cataract and glaucoma, family II had mainly glaucoma, while in family III all individuals had cataract but none had evidence of glaucoma. The first generation of these three families were deceased but their hospital and clinical records revealed that in all three families the father was affected and there was no evidence of maternal involvement. CONCLUSIONS: In all three families, pseudoexfoliation appeared to be genetically transmitted as a late onset autosomal dominant trait of variable expression. Maternal transmission could not be confirmed in these families.

Adult↗
PubMed2005

Development of a shape memory alloy multiple-point injector for chemotherapy.

A medical needle is described that allows injection to take place at multiple sites through a single stab wound. This is achieved by extruding multiple, thin, and curved internal needles from a larger, straight, outer needle. The development and finite element modelling of the shape memory alloy (SMA) inner needles is presented in this paper. A non-linear elastic element model was used in this process to allow for the non-linear properties of the alloy and the large deformations that occur. The model provided maximum strain values and penetration forces for the inner needles. The deformation force on the tip of the needle was measured against displacement to confirm the predicted penetration force. Applications for the device include the treatment of liver cancer by direct injection of alcohol into the tumours.

Alloys↗