Biomedical subjects

Andrew B Lederman

Publications and source records attributed to Andrew B Lederman.

4 recordsLinked to original sources

PubMed2005

Video-assisted surgery represents more than a loss of three-dimensional vision.

BACKGROUND: Loss of depth cues is a major challenge facing surgeons performing video-assisted surgery (VAS). Whether the degradation of image quality from a video-displayed image plays a direct role in performance of VAS has not been studied. METHODS: Twenty-four volunteer novice subjects were randomized to binocular direct-vision (BDV), monocular direct-vision (MDV), or video-imaging (VI) conditions. Each subject completed ten trials of a simple cutting task in a box trainer using standard laparoscopic instruments. RESULTS: VI subjects made significantly fewer correct incisions than both of the other groups for all trials. Differences between the BDV and MDV groups did not reach statistical significance. Improvement in performance was more rapid in the BDV group than in either the MDV or VI groups. CONCLUSIONS: The degradation of image quality with VI has a detrimental influence on VAS performance above and beyond the loss of binocular vision.

Adult↗

PubMed2005

When fundoplication fails: redo?

OBJECTIVE: The largest series in the literature dealing with redo fundoplication was presented and published in 1999 and included 100 patients. Herein we update this initial series of 100, with 207 additional patients who have undergone redo fundoplication (n = 307). SUMMARY BACKGROUND DATA: Increasing numbers of patients are failing esophagogastric fundoplication and requiring redo procedures. Data regarding the nature of these failures have been scant. METHODS: Data on all patients undergoing foregut surgery are collected prospectively. Between 1991 and 2004, 307 patients underwent redo fundoplication for the management of anatomic complications or recurrent GERD. Statistical analysis was performed with multiple chi2 and Mann-Whitney U analyses, as well as ANOVA. RESULTS: Between 1991 and 2004, 1892 patients underwent primary fundoplication for GERD (1734) or paraesophageal hernia (158). Of these, 54 required redo fundoplication (2.8%). The majority of failures (73%) were managed within 2 years of the initial operation (P = 0.0001). The mechanism of failure was transdiaphragmatic wrap herniation in 33 of 54 (61%). In the 231 patients who underwent fundoplication elsewhere, 109 had transdiaphragmatic herniation (47%, P = NS). In this group of 285 patients, 22 (8%) required another redo (P = NS). The majority of the procedures were initiated laparoscopically (240/307, 78%), with 20 converted (8%). Overall mortality was 0.3%. CONCLUSIONS: Failure of fundoplication is unusual in experienced hands. Most are managed within 2 years of the initial operation. Wrap herniation has now become the most common mechanism of failure requiring redo. Redo fundoplication was successful in 93% of patients, and most could be safely handled laparoscopically.

Fundoplication↗

PubMed2005

A short-term delayed approach to laparoscopic ventral hernia when injury is suspected.

Laparoscopic repair is a safe and effective method for treating ventral hernias. Although the risk of bowel injury is low, its management is controversial. When injury is suspected or repaired, the risk of infection might prohibit a repair with prosthetic mesh. The timing of safe mesh placement is unclear. We retrospectively reviewed 9 patients from our prospective laparoscopic ventral hernia database who were treated with a 2- to 6-day delay in mesh placement due to violation of the gastrointestinal tract or risk of unidentified or delayed injury. All 9 patients had large ventral hernias from previous laparotomies (average defect, 399.4 cm2) and presented for elective repair. Three of the patients were morbidly obese, and one was diabetic. The decision to delay mesh placement was made intraoperatively. Reasons for delay were colotomy with repair, extensive serosal tears, resection after enterotomy, and resection for chronic small bowel obstruction. All patients received broad-spectrum antibiotics while awaiting definitive repair. In 7 patients, mesh was successfully placed between postoperative days 2 and 6. Delayed mesh placement failed in 2 patients due to loss of domain with bowel edema. The average length of stay was 9 days (range, 6 to 15 days) and average follow-up was 136 days (range, 36 to 303 days). No early mesh infections or other major complications were reported. A short delay of 2 to 6 days with antibiotic coverage is a safe strategy for managing potential or recognized injury to the gastrointestinal tract during laparoscopic ventral hernia repair.

Adult↗

PubMed2003

Objective psychomotor skills assessment of experienced and novice flexible endoscopists with a virtual reality simulator.

The objective of this study was to determine whether the GI Mentor II virtual reality simulator can distinguish the psychomotor skills of intermediately experienced endoscopists from those of novices, and do so with a high level of consistency and reliability. A total of five intermediate and nine novice endoscopists were evaluated using the EndoBubble abstract psychomotor task. Each subject performed three repetitions of the task. Performance and error data were recorded for each trial. The intermediate group performed better than the novice group in each trial. The differences were significant in trial 1 for balloons popped (P=.001), completion time (P=.04), and errors (P=.03). Trial 2 showed significance only for balloons popped (P=.002). Trial 3 showed significance for balloons popped (P=.004) and errors (P=.008). The novice group showed significant improvement between trials 1 and 3 (P<0.05). No improvement was noted in the intermediate group. Measures of consistency and reliability were greater than 0.8 in both groups with the exception of novice completion time where test-retest reliability was 0.74. The GI Mentor II simulator can distinguish between novice and intermediate endoscopists. The simulator assesses skills with levels of consistency and reliability required for high-stakes assessment.

Adult↗