Insulation failure in laparoscopic instruments.

BACKGROUND: Electrosurgery is used in virtually every laparoscopic operation. In the early days of laparoscopic surgery, capacitive coupling, associated with hybrid trocars, was thought to be the major cause of laparoscopic electrosurgery injuries. Modern laparoscopy has reduced capacitive coupling, and now insulation failure is thought to be the main cause of electrosurgical complications. The aim of this study was (1) to determine the incidence of insulation failures, (2) to compare the incidence of insulation failure in reusable and disposable instruments, and (3) to determine the location of insulation failures.
METHODS: At four major urban hospitals, reusable laparoscopic instruments were checked for insulation failure using a high-voltage porosity detector. Disposable L-hooks were collected following laparoscopic cholecystectomy and similarly evaluated for insulation failure. Instruments were determined to have insulation failure if 2.5 kV crossed the instrument's insulation to create a closed loop circuit. Statistical analysis was performed using Fisher's exact or chi(2) analysis (*denotes significance set at p < 0.05).
RESULTS: Two hundred twenty-six laparoscopic instruments were tested (165 reusable). Insulation failure occurred more often in reusable (19%; 31/165) than in disposable instruments (3%; 2/61; *p < 0.01). When reusable sets were evaluated, 71% (12/17) were found to have at least one instrument with insulation failure. Insulation failure incidence in reusable instruments was similar between hospitals that routinely checked for insulation failure (19%; 25/130) and hospitals that do not routinely check for insulation failures (33%; 7/21; p = 0.16). Insulation failure was most common in the distal third of the instruments (54%; 25/46) compared to the middle or proximal third of the instruments (*p < 0.05).
CONCLUSION: One in five reusable laparoscopic instruments has insulation failure; a finding that is not altered by whether the hospital routinely checks for insulation defects. Disposable instruments have a lower incidence of insulation failure. The distal third of laparoscopic instruments is the most common site of insulation failure.