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Biomedical subjects

A Cuschieri

Publications and source records attributed to A Cuschieri.

At least 127 records · Page 7Linked to original sources

Optimal port locations for endoscopic intracorporeal knotting.

Port location is crucial for endoscopic manipulations. The aim of the study was to investigate the influence of manipulation, azimuth, and elevation angles of instruments on endoscopic intracorporeal knotting. The standard task was tying a surgeon's knot. Manipulation angles of 30 degrees , 45 degrees , 60 degrees , 75 degrees , and 90 degrees with equal and unequal azimuth angles and elevation angles of 0 degrees , 30 degrees , and 60 degrees were investigated. The endpoints were the execution time and parameters of knot analysis. The execution time was shorter with 60 degrees than with either 90 degrees or 30 degrees manipulation angles (p < 0.0001 and p < 0. 01). Equal azimuth angles resulted in a shorter execution time than wide unequal angles (p < 0.001). A combination of 60 degrees manipulation angle with 60 degrees elevation angle had the shortest execution time (p < 0.001) and highest performance quality score (p < 0.02). A range of 45 degrees -75 degrees manipulation angles with equal azimuth angles is recommended. As the manipulation angle increases, the elevation angle has to increase accordingly.

Endoscopes↗

Prehensile atraumatic grasper with intuitive ergonomics.

BACKGROUND: Minimal access surgery (MAS) procedures that require tissue to be grasped are impeded by the design of current instruments. The use of graspers and forceps can result in tissue damage and is highly inappropriate when handling larger organs such as the bowel, liver, and spleen. In addition, current instruments have unnatural handling characteristics. A new type of tissue grasper is presented as a solution to these problems. METHODS: The new grasper design was evolved through a process of setting basic requirements and proceeding through cycles of design, construction, evaluation, and re-design. RESULTS: The main features of the new device are prehensile grasping by finger-like jaws, which retain tissue by 'capture,' and a novel handle design with intuitive ergonomics. The jaws are interchangeable to suit differing surgical tasks and the handle and trigger mechanism are designed so that the surgeon's forefinger movement mirrors the instrument jaw action. The grasper has been used in 32 MAS procedures with no indications of trauma. CONCLUSIONS: A grasper that functions by capture has been demonstrated to be an effective solution for atraumatic tissue handling during many MAS procedures.

Endoscopes↗

Transcystic biliary decompression after direct laparoscopic exploration of the common bile duct.

BACKGROUND: A purpose-designed transcystic common bile duct (CBD) decompression cannula is described for use as an alternative to T-tube insertion following laparoscopic direct CBD exploration. This permits safe primary closure of the choledochotomy. METHODS: Following direct supraduodenal laparoscopic clearance of large common bile duct stones, the biliary decompression cannula is inserted percutaneously inside its peel-away sheet over a guide-wire into the CBD via the cystic duct. When in place, the cannula is secured to the cystic duct by two catgut extracorporeal Roeder knots and the choledochotomy is then closed. The terminal multiperforated S-shaped segment of the Cuschieri biliary decompression cannula prevents postoperative dislodgement. RESULTS: Transcystic decompression of the extrahepatic biliary tract using the Cuschieri cannula has been used in 12 patients who underwent laparoscopic supraduodenal CBD exploration for large or occluding stones. There was no instance of postoperative dislodgement of the cannula and all patients had effective drainage of the common bile duct (average 300 ml bile per 24 h). The procedure was uncomplicated in all but one patient who developed self-limiting leakage from the CBD suture line in the early postoperative period. The median hospital stay after surgery was 4 days, with a range of 3 to 10 days. The cystic duct decompression cannula was capped and sealed under an occlusive dressing at the time of discharge. Removal of the cannula was carried out without any complications as a day case 11-16 days after surgery. CONCLUSIONS: Transcystic biliary decompression is safe and effective. The experience with is use indicates that compared to T-tube drainage, transcystic decompression may accelerate recovery and reduce the hospital stay in patients following laparoscopic direct exploration of the CBD. Its insertion is less technically demanding than placing a T-tube through the choledochotomy. Transcystic decompression with complete primary closure of the CBD realizes the full benefits of the single-stage management of common bile duct calculi and permits confirmation of complete stone clearance after surgery.

Aged↗

Objective assessment of endoscopic knot quality.

BACKGROUND: Studies of the surgeon's skill and the ergonomics of task performance in endoscopic surgery can be based on knot-tying tasks. The aim of this study was to establish an objective method for assessing the quality of surgical knots for use in such studies. METHODS: In all, 2,700 surgeon's endoscopic knots were studied. Each knot was distracted using a tensiometer, and a computerized system analyzed force-extension curves. The breaking force was taken as an index of knot strength while the force integrated over the slope of the curve reflected knot tightening. A knot quality score (KQS) was obtained from the product of the knot-breaking force and the integrated force expressed as a percentage of the product for the untied ligature. RESULTS: The mean breaking force (24 Newton +/- 2.5) and integrated force (7.4 Newton +/- 2.8) for broken knots were 71% and 35%, respectively, of those for untied ligature. The integrated force yielded a narrower range of variability for untied ligature (SD 3.5% of mean) than for knots (SD 37% of mean). The KQS was higher for broken (25.3%+/-10.3%) than slipped knots (7.1%+/-5.1%). CONCLUSION: The KQS provides a reliable assessment of knot security and reflects the strength and degree of tightening of the knot.

Clinical Competence↗

Comparison of direct monocular endoscopic, two- and three-dimensional display systems on surgical task performance in functional endoscopic sinus surgery.

Surgeons performing functional endoscopic sinus surgery (FESS) traditionally rely on direct endoscopic viewing through a single monocular Hopkins rod lens telescope. While the majority of surgeons have found this satisfactory, most other endoscopic surgical specialties have moved to 2-D video endoscopy, where a monoscopic image is presented on a television monitor. This study set out to determine whether 2-D or 3-D display systems had any advantage over direct endoscopy in FESS. Ten otolaryngology trainees performed a series of standardized procedures on a FESS model using direct endoscopic vision, 2-D and 3-D. A performance score was obtained by dividing the execution time by the number of tasks achieved. There was a significant difference in both surgical and diagnostic task performance with 2-D (mean scores 56.8 and 41.1) performing better than direct endoscopy (mean scores 94.1 and 74.1) (P < 0.05). Tasks were also performed significantly better with 3-D compared with 2-D (P < 0.05).

Endoscopy↗

Preface.

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Journal Article↗

Developing Technology for Suspended Imaging for Minimal Access Surgery.

Some of the problems of performing laparoscopic surgery can be traced to the position and intrinsic qualities of the displayed video image. Conversion of the normal monitor screen image to a suspended image can reduce image-related difficulties. The principles of suspended image production are described and the potential for more flexible image positioning and enhanced depth perception is explained. A recently initiated research program is investigating design possibilities and conducting fundamental research into suspended image appraisal.

Journal Article↗

Technology for Psychomotor Skills Testing in Endoscopic Surgery.

Psychomotor research is essential for aptitude-based selection of surgical trainees and sound surgical practice. Two microprocessor-controlled psychomotor testers were developed to evaluate psychomotor skills related to endoscopic surgery. Dundee Endoscopic Psychomotor Tester (DEPT) measures single-handed performance in an endoscopic environment and therefore it can be used to evaluate differing abilities between the right and left hand. Advanced Dundee endoscopic Psychomotor Tester (ADEPT) measures two-handed performance, and consequently it can be used to assess coordinated bimanual endoscopic manipulations. Psychomotor testers provide real-time objective scoring systems that have several aspects of face validity to real endoscopic environment. Studies on medical students have confirmed that objective evaluation of task performance in an endoscopic field is feasible and have documented differences in psychomotor abilities between subjects.

Journal Article↗

Laparoscopic common bile duct exploration after failed endoscopic stone extraction.

BACKGROUND AND STUDY AIMS: Despite the documented success rate and safety of laparoscopic ductal stone extraction, the majority of patients are treated with preoperative endoscopic stone extraction followed by laparoscopic cholecystectomy. When this fails, conventional open cholecystectomy and common bile duct exploration are performed. We report here a series of patients who were treated laparoscopically after failed attempts at endoscopic stone extraction. PATIENTS AND METHODS: Nineteen patients (12 women and seven men, aged 41-96 years) were treated laparoscopically. Four had undergone previous cholecystectomy. ERCP had been attempted in all patients, was unsuccessful in three patients, and had been interpreted as normal in two. Endoscopic stone extraction had been attempted in 14 patients. The mean follow-up period was 23 months, range 1-54 months. RESULTS: Ductal calculi were confirmed in 18 patients with successful and complete laparoscopic ductal clearance in 15 (83%), two of whom underwent an additional laparoscopic choledochoduodenostomy due to a large stone load and a grossly dilated common bile duct. Conversion to open surgery was required in three cases (17%). Ductal clearance at a single operation was achieved in all 18 patients. There were no postoperative deaths, but two patients developed postoperative complications (11% morbidity), one requiring laparotomy. The median postoperative hospital stay was five days, range 4-41 days. Recurrence of calculi was encountered in one patient. CONCLUSIONS: Laparoscopic ductal stone clearance after failed endoscopic stone extraction is successful in the majority of patients, and should be attempted prior to recourse to open surgery, provided the necessary laparoscopic biliary expertise is available.

Adult↗

Psychomotor skills for endoscopic manipulations: differing abilities between right and left-handed individuals.

OBJECTIVE: The objective of this study was to compare the psychomotor aptitudes relevant to endoscopic manipulations between right-handed and left-handed subjects. SUMMARY BACKGROUND DATA: There has been little research on the psychomotor performance in relation to minimal access surgery and there are no psychomotor tests to evaluate aspects of psychomotor abilities relevant to endoscopic manipulations. METHODS: A microprocessor-controlled psychomotor tester was developed for objective evaluation of endoscopic performance. The task involved negotiating ten target holes with a probe under videoscopic imaging. Subjects consisted of two groups of 10 medical students: right- and left-handed. After a prestudy familiarization session, each subject performed two test runs with one hand, followed by two runs with the other hand. These test runs were repeated 1 week later. The outcome measures were the total execution time, force on backplate, angular deviations, error rate, and first-time accuracy. RESULTS: A significant difference in the error rate and first time accuracy was observed between subjects (p < 0.001 and p < 0.001, respectively) and between the dominant and nondominant hands (p < 0.001 and p < 0.025, respectively), with no significant change with practice. Right-handed subjects performed better with either hand in terms of error rate (p < 0.001) and first time accuracy (p < 0.001). Practice improved the execution time (p < 0.001) and the degree of angular deviations (p < 0.02). CONCLUSIONS: Right-handed subjects perform less errors and exhibit better first time accuracy. The parameters that improve with practice reflect the positive effect of training, whereas others, such as errors rate and first time accuracy which do not, reflect innate abilities.

Endoscopy↗

Technological aspects of minimal access surgery.

Minimal access surgery (MAS) is bringing about a revolution in surgical practice with certain operations being almost wholly carried out using MAS techniques in some countries. This paper describes the development, current status and future prospects of MAS from a technological perspective.

Biomedical Engineering↗

Training initiative list scheme (TILS) for minimal access therapy: the MATTUS experience.

The objective of the MATTUS intercollegiate exercise was to set up and audit a training initiative list scheme (TILS) by which funds are awarded to Trust hospitals for operative sessions used specifically for the training of staff in minimal access therapy (MAT). A prospective centralized audit of TILS involving nine Trust hospitals in Scotland over a 12-month period (1 March 1995-end of February 1996) was carried out. These hospitals had contracted for 510 4-h training sessions (389 for minimal access surgery, 121 for allied interventional techniques) by MATTUS accredited consultant tutors. The scheme covered training in technical competence for Minimal Access Surgery (MAS), interventional flexible endoscopy and interventional radiology within Scottish Hospitals. The main outcome measures used in the audit were trainee completion rates, conversion rates, morbidity and mortality, assessment of training received by trainees and assessment of aptitude by the trainers. The results were as follows. Of 510 sessions, 482 (95%) were completed within the deadline. Of these, 463 sessions were audited (367 for MAS, 69 for flexible endoscopy and 27 for interventional radiology). During these sessions, 817 operations/procedures were performed (781 training and 36 developmental). A total of 544 operations were performed during 339 MAS training sessions and 237 radiological/flexible endoscopy procedures in 96 MAT training sessions. The trainee was the principal operator in 643 (82%) procedures and completed the task in 581 (74%) cases. Four per cent of the MAS operations (22/544) required conversion. Post-operative complications occurred in 42 out of 817 patients (5%). Four patients, all with advanced malignancy, died within 30 days of the procedure. Trainees graded 355 sessions as excellent, 109 good, two as average and one as unsatisfactory. The tutors graded their trainees' aptitude to perform the operation as excellent in 34%, good in 53%, average in 11% and poor in < 1%. The training initiative list scheme which allows unhurried training in MAT by consultant tutors using operating sessions that are extra to the service lists is operationally and educationally viable. Furthermore, it can be implemented within a pre-determined budget. The audit of TILS has also demonstrated that the immediate clinical outcome of patients is not compromised by this type of training.

Education, Medical, Graduate↗

Influence of direction of view, target-to-endoscope distance and manipulation angle on endoscopic knot tying.

INTRODUCTION: The aim of the study was to investigate the influence of (1) the direction of view of the endoscope, (2) the endoscope-to-task distance and (3) the manipulation angle between the instruments on intracorporeal endoscopic knotting. METHODS: Rigid endoscopes (0 degree, 30 degrees and 45 degrees) were introduced with the objective set at distances of 50, 75, 100, 125 and 150 mm from the task. Needle holders were inserted to make 30 degrees, 60 degrees and 90 degrees manipulation angles. The execution time and knot quality parameters of 2700 knots performed by ten surgeons were obtained. RESULTS: There was no significant difference in the execution time or parameters of knot quality with different endoscopes. The longest execution time (median 95 s, P < 0.0001) and the lowest performance quality score (20.61, P < 0.001) were observed at a distance of 50 mm when compared to other distances. A 60 degrees manipulation angle had a shorter execution time (median 71 s, P < 0.0001) and a higher performance quality score (26.84, P < 0.0001) than either 30 degrees or 90 degrees manipulation angles. CONCLUSION: The direction of view of the endoscope had no significant effect on intracorporeal knotting if the optical axis subtended the same angle with the task surface. The optimal ergonomic conditions include an endoscope-to-target distance of 75-150 mm and a manipulation angle of 60 degrees.

Endoscopy↗

Postoperative morbidity and mortality after D1 and D2 resections for gastric cancer: preliminary results of the MRC randomised controlled surgical trial. The Surgical Cooperative Group.

BACKGROUND: In Japan the surgical approach to treatment of potentially curable gastric cancer, including extended lymphadenectomy, seems in retrospective surveys to give better results than the less radical procedures favoured in Western countries. There has, however, been no evidence from randomised trials that extended lymphadenectomy (D2 gastric resection) confers a survival advantage. This question was addressed in a trial involving thirty-two surgeons in Europe. METHODS: In a prospective randomised controlled trial, D1 resection (level 1 lymphadenectomy) was compared with D2 resection (levels 1 and 2 lymphadenectomy). Central randomisation (200 patients in each arm) followed a staging laparotomy. FINDINGS: The D2 group had greater postoperative hospital mortality (13% vs 6.5%; p=0.04 [95% Cl 9-18% for D2, 4-11% for D1] and higher overall postoperative morbidity (46% vs 28%; p<0.001); their postoperative stay was also longer. The excess postoperative morbidity and mortality in the D2 group was accounted for by distal pancreaticosplenectomy and splenectomy. In the whole group (400 patients), survival beyond three years was 30% in patients whose gastrectomy included en-bloc pancreatico-splenic resection versus 50% in the remainder. INTERPRETATION: D2 gastric resections are followed by higher morbidity and mortality than D1 resections. These disadvantages are consequent upon additional pancreatectomies and distal splenectomies, and in long-term follow-up the higher mortality when the pancreas and spleen are resected may prove to nullify any survival benefit from D2 procedures.

Adenocarcinoma↗