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Biomedical subjects

A Darzi

Publications and source records attributed to A Darzi.

At least 109 records · Page 6Linked to original sources
PubMed1999

Comparison of immunologic and physiologic effects of CO2 pneumoperitoneum at room and body temperatures.

BACKGROUND: Prolonged and complex laparoscopic procedures expose patients to large volumes of cool insufflation gas. The aim of this study was to compare the effects of a conventional room temperature carbon dioxide (CO2) pneumoperitoneum with those of a body temperature pneumoperitoneum. METHODS: Patients were randomized to undergo laparoscopic cholecystectomy with a CO2 pneumoperitoneum warmed to either body temperature (n = 15) or room temperature (n = 15). The physiologic and immunologic effects of warming the gas were examined by measuring peroperative core and intraperitoneal temperatures, peritoneal fluid cytokine concentrations, and postoperative pain. RESULTS: The mean duration of surgery was 32 min in both groups. Core temperature was reduced in the room temperature group (mean, 0.42 degrees C; p < 0.05). No reduction in temperature occurred when the gas was warmed. Greater levels of cytokines were detected in peritoneal fluid from the room temperature insufflation group tumor necrosis factor alpha (TNF-alpha): mean, 10.9 pg/ml vs. 0.42, p < 0.05; interleukin 1 beta (IL-1beta): mean, 44.8 pg/ml vs. 15.5, p < 0.05; and IL-6: mean, 60.4 ng/ml vs. 47.2. There was no difference in postoperative pain scores or analgesia consumption between the two groups. CONCLUSIONS: The authors conclude that intraoperative cooling can be prevented by warming the insufflation gas, even in short laparoscopic procedures. In addition, warming the insufflation gas leads to a reduced postoperative intraperitoneal cytokine response.

Ascitic Fluid↗
PubMed1999

Laparoscopic surgery in a 0.5-t interventional magnetic resonance unit.

BACKGROUND: Intraoperative imaging using magnetic resonance imaging (MRI) is now possible in interventional MR (IMR) units. Magnetic resonance imaging has potential advantages over other methods used to guide surgery. These advantages include visualization of structures deep to the two-dimensional endoscopic image and clarification of surgical anatomy. This study investigates the feasibility of laparoscopic surgery with intraoperative imaging within an IMR unit. METHODS: The procedures were performed in a 0. 5-T General Electric IMR scanner. Surgical ergonomics and intraoperative imaging were investigated by performing 10 laparoscopic cholecystectomies on porcine livers in a simulator using magnet-safe laparoscopic instruments and an ultrasonic scalpel for dissection. Intraoperative MR cholangiography (MRC) was performed using T2-weighted fast-spin-echo (FSE) and single-shot fast-spin-echo (ssFSE) techniques with maximal intensity projection (MIP) reconstruction. Two laparoscopic cholecystectomies then were performed on human patients with intraoperative MRC using similar techniques. RESULTS: The simulated procedures allowed the development of surgical techniques appropriate to this environment. Both FSE and ssFSE produced reasonable quality intraoperative images. Both patient procedures were performed without complication. The FSE imaging was of poor quality. However, ssFSE produced intraoperative images of the gallbladder with partial visualization of the extrahepatic biliary tree. CONCLUSIONS: Laparoscopic surgery in an IMR unit is technically possible. Currently, intraoperative MRC is difficult, and FSE imaging is very subject to movement artifact. However, the faster ssFSE, with further development, may be a useful technique for intraoperative imaging of the biliary tree during MR-guided surgery.

Adult↗
PubMed1999

Rigid videosigmoidoscopy vs conventional sigmoidoscopy. A randomized controlled study.

BACKGROUND: Not only is rigid sigmoidoscopy uncomfortable for patients, but visualisation of the rectosigmoid junction and sigmoid colon is successful in only 40-70% of examinations. A novel fine-bore rigid videosigmoidoscope is described and then compared with a rigid conventional sigmoidoscope for patient discomfort and length of insertion. METHOD: A total of 58 patients were examined with both sigmoidoscopes in a random order. Discomfort was scored on a visual analogue scale; length of insertion was scored by the surgeon. Patients were blinded to which sigmoidoscope was being used. The images from the video examination were transmitted in real time for a second opinion in a different hospital. RESULTS: The mean (SD) insertion distance of the videosigmoidoscope was 23.2 (5.9) cm, which was significantly further than with the conventional sigmoidosocpe 16.5 (3.8) cm (p < 0.01). The discomfort on a visual analogue score for the videosigmoidoscope was 3.0 (1.8), which was significantly less than for the conventional sigmoidoscope 5.5 (2.7) (p < 0.01). The five users of the equipment (four surgeons and one colorectal nurse practitioner) preferred the videosigmoidoscope for image quality and ease of examination. CONCLUSIONS: A thinner, longer, rigid videosigmoidoscope is a more effective means of looking at the proximal sigmoid colon. Despite being inserted further, it caused less discomfort than the conventional sigmoidoscope. High-quality video images can be recorded or transmitted for real-time teleconsultation.

Humans↗
PubMed1999

The effect of a second-generation 3D endoscope on the laparoscopic precision of novices and experienced surgeons.

BACKGROUND: Endoscopic surgeons rely on visual feedback to control their movements but lack stereopsis, an important depth cue. Previous three-dimensional (3D) systems alternated images on a two-dimensional (2D) screen, which was uncomfortable for surgeons. A second-generation 3D system provides continuous stereoscopic images on a monitor suspended at arm's length. We studied its effect on the laparoscopic precision of novices and experienced surgeons. METHODS: Experienced laparoscopic surgeons (n = 12) and novices (n = 16) performed a total of 672 tasks in 2D, 3D, and under direct vision. Precision was assessed using the Imperial College Surgical Assessment Device (ICSAD), which generates objective scores of performance by analyzing the movements of surgical instruments. RESULTS: We found that 2D endoscopic vision impaired performance by 35-100% when compared with direct vision, whereas 3D reduced this endoscopic handicap by 41-53% in novices and experienced surgeons (p < 0.03). No side effects were reported with the new 3D system. Even in 2D, novices performed better with an image at arm's length (p < 0. 03). CONCLUSIONS: Second-generation 3D significantly improved the laparoscopic precision of novices and experienced surgeons, without the side effects reported from previous systems. This technology is expected to improve the ease and safety of laparoscopic surgery.

Adolescent↗
PubMed1999

Undergraduate surgical teaching utilizing telemedicine.

OBJECTIVES: To evaluate the concept of a new telemedicine orientated educational application by exposing junior medical students to surgical teaching via video-conferencing from the operating theatre and comparing this to the traditional method currently employed, which requires the presence of students in the operating room. To determine student satisfaction with this novel method and identify deficiencies associated with traditional surgical teaching. DESIGN: Students were connected by video-conferencing equipment 2 Mbit/s permanent virtual circuits that provided two-way picture and voice communication. Traditional tutoring involved students attending the operating theatre in set numbers. Video recordings were made during the telemedicine transmission for highlighting important factors relevant to the operative procedure. A questionnaire was used to assess the quality of time spent and information obtained by the students. SETTING: Telemedicine centre and operating theatre, St Mary's Hospital, London. SUBJECTS: Junior clinical students. RESULTS: The median score for surgical teaching utilizing video-conferencing was 9 (scale 0-10) compared to 5 for traditional operating theatre surgical teaching. All 46 (100%) subjects indicated a willingness to return for the telemedicine influenced method of tutoring compared to 65% of students exposed to the conventional method. CONCLUSIONS: Our early experience with telemedicine assisted surgical teaching indicate high acceptance and satisfaction rates by clinical students. Further studies to evaluate the objective gain in knowledge associated with this method is required prior to its implementation in any future medical curriculum.

Consumer Behavior↗
PubMed1999

Sigmoidoscopy in a nurse-practitioner community clinic using telemedicine.

We evaluated the feasibility of remote endoscopy in a community setting. Realtime teleconsultation and telesigmoidoscopy were carried out by a nurse practitioner at a community clinic while a colorectal specialist was present at the main hospital. Rigid video-sigmoidoscopes were used and the images were transmitted via ISDN lines at 384 kbit/s. Over three months, 32 patients (mean age 35 years; 19 men and 13 women) with bleeding per rectum took part in the study. Evaluation was carried out using satisfaction questionnaires for the patients, the nurse practitioner and the clinicians. The mean grade for clarity of intraluminal views was 3.5 (1 poor, 4 excellent). Only two cases had views graded less than 3, due to the presence of excessive faecal residue. All the patients were satisfied with the teleconsultation and video-endoscopy and would return for a similar visit. User satisfaction was also high on the part of the nurse practitioner and the clinician.

Adult↗
PubMed1999

Realtime remote consultation in the outpatient clinic--experience at a teaching hospital.

We used an outpatients' telemedicine clinic to evaluate remote consultation in a London hospital practice. Video-images were relayed by ISDN at 384 kbit/s between the main hospital site and the sister hospital. Teleconsultation was evaluated in three different specialties: pain management, orthopaedics and general surgery. Medical personnel involved in the consultation consisted of a resident or senior house officer at the remote site and a senior registrar or consultant at the main hospital. A total of 146 consultations was held over a six-month period in the three clinical specialties involved. Questionnaires were completed by 58% of patients and over 90% of the medical personnel involved. The mean scores (on a five-point Likert scale) for physician satisfaction at the main and distant site were 3.6 and 3.8, respectively. On a scale of 0-10, 92% of patients rated the consultation 8-10 and 90% indicated that they would return for a similar consultation. Seventy-three per cent felt that a similar consultation from their referring doctor would have been appropriate. Confidence in the diagnosis was high among the specialists at the main hospital site.

Computer Systems↗
PubMed1999

Use of telemedicine in undergraduate teaching of surgery.

Telemedicine as an undergraduate teaching method was evaluated by exposing medical students to outpatient videoconferencing. Forty clinical students on a 10-week surgical rotation participated in the study. Telemedicine sessions involved videoconferencing from the general surgical outpatient department located in a sister hospital 8 km away, using a roll-about system connected by ISDN at 384 kbit/s. A questionnaire was used to assess the quality of time spent and educational information obtained by the students. On a scale of 0-10, the students gave an overall rating of 9.7 for outpatient teaching using telemedicine. All 40 students indicated a willingness to return for similar teaching sessions. Even though the results were encouraging, an objective assessment of the knowledge gained by the students is required before the inclusion of this teaching technique in an existing medical curriculum can be recommended unequivocally.

Attitude↗
PubMed1999

Objective assessment of surgical dexterity using simulators.

Surgical skill, like training for any craft, has traditionally been learnt as an apprenticeship. However, whereas carpenters learn on wood that is never displayed, operative training is done on real clinical cases. Over recent years surgical skills training laboratories have in part, replaced the apprenticeship. This article discusses some of the tools used within such laboratories to ensure optimal surgical performance.

Clinical Competence↗
PubMed1999

Early experience and validation work with Procedicus VA--the Prosolvia virtual reality shoulder arthroscopy trainer.

Shoulder arthroscopy is a difficult procedure, commonly used for both diagnostic and therapeutic purposes. Until now, the majority of training has been done in theatre, assisting and practising under supervision. Few good simulations exist. Procedicus VA, from Prosolvia Clarus, is a virtual reality simulation of shoulder arthroscopy, with interactive graphics and haptic feedback. The simulator has various modes including anatomy manipulation pathology subacromial decompression. We describe our experience with the simulator, attempting to validate some of the scoring mechanisms, and highlighting some of the pitfalls discovered as the simulator is first trialled by surgeons. This early experience has highlighted both successful aspects of the simulator, and some of the initial pitfalls. Our initial experience confirms the need for close collaboration between virtual programmers and surgical trainers. We are revising the assessment criteria over the coming months.

Arthroscopy↗
PubMed1999

Magnetic resonance guided general surgery.

Image guided surgery can be defined as the intraoperative use of a radiologicai technique to give the surgeon information not available from direct inspection or palpation of the surgical field. This information may then be used to change the course of an operative procedure. Magnetic resonance (MR) imaging has the potential to be the most useful radiologicai technique in the developing field of image guided surgery.

Journal Article↗
PubMed1998

Does the ultrasonically activated scalpel release viable airborne cancer cells?

BACKGROUND: Viable cancer cells may implant at distant sites and cause tumor recurrence. One possible mechanism is the inadvertent exfoliation of viable tumor cells during dissection. The ultrasonically activated scalpel (UAS) uses ultrasonic energy to disrupt tissues by cavitation and produces a dense cloud of cellular debris that may contain viable cells. This study aimed to investigate the viability of airborne cells released during cancer dissection using the UAS and electrosurgery. METHODS: Flank tumors (n = 8) measuring 1 cm3 were induced in male WAG rats by subcutaneous injection of 2 x 10(6) CC531s colon cancer cells. Dissection was performed in cutting mode using the maximum power output of the respective devices. Electrosurgery was performed using a standard monopolar electrosurgical unit and a needle probe, and ultrasonic dissection was performed with the Harmonic Scalpel utilising the open surgical handset and the hooked spatula tip. The smoke plume was aspirated by a vacuum pump and bubbled under Hank's balanced salt solution to trap particulate matter. The viability of the cellular material was blindly assessed with the trypan blue test and by in vitro culture. The morphology of the cellular debris was studied by examination of cytospin preparations. RESULTS: Large quantities of cellular debris was trapped in the plume from both devices. However, no viable cells were isolated, nor did in vitro cell growth occur with either device. Examination of the debris from the UAS demonstrated a characteristic mixture of amorphous forms and very few morphologically intact cells. The cauterized tumor produced charred cells and tissue fragments. CONCLUSIONS: In conclusion, this study demonstrates that viable airborne cancer cells are not released after tumor ablation with the UAS or electrosurgery.

Animals↗
PubMed1998

Late-onset deep prosthetic infection following mesh repair of inguinal hernia.

BACKGROUND: The use of prosthetic biomaterials for the primary repair of inguinal hernias is now commonplace. Late-onset deep-seated prosthetic infection can be an unexpected complication. METHODS: The literature from a Medline search relating to the biology of mesh in the setting of hernia repair is discussed. CONCLUSIONS: The use of a foreign body for hernia repair does not appear to alter the incidence of superficial wound infection. Late-onset deep graft infection has been rarely reported, and the true incidence is yet to be established. With the more widespread use of mesh materials, this complication may become increasingly evident.

Anti-Bacterial Agents↗