PII:S0003—6870(98)00016-7 Applied Ergonomics Vol. 29, No. 6, pp. 409—414, 1998  1998 Elsevier Science Ltd All rights reserved. Printed in Great Britain 0003—6870/98 $19.00#0.00 Errors enacted during endoscopic surgery—a human reliability analysis P. Joice, G. B. Hanna and A. Cuschieri* Department of Surgery and Surgical Skills ºnit, Ninewells Hospital and Medical School, ºniversity of Dundee, Dundee, Scotland DD19S½, ºK (Received 19 June 1997; in revised form 22 January 1998) The aim of the study was to document the nature and incidence of surgical errors enacted during laparoscopic surgery in order to direct future research and surgical training. A modified Human Reliability Analysis (HRA) approach, based on direct observation, was adopted to categorise and record errors encountered during the practice of laparoscopic cholecystectomy. This study con- firmed the applicability and usefulness of an observational methodology in the assessment of human error in endoscopic surgical performance. The study identified aspects of the design and usage of instruments, surgical training and the differences between tasks which needed further directed research in order to identify underlying performance shaping factors (PSFs) and so reduce error rates.  1998 Elsevier Science Ltd. All rights reserved. Keywords: human error, laparoscopic cholecystectomy, observational methodology Introduction Laparoscopic or keyhole surgery is the practice of sur- gery using the smallest practical incision to gain access to internal organs and carry out surgical procedures. The small size of incisions means that the control of surgical instruments and the visual display of the surgical work- space has to take place remotely, outside the patient’s body. This arrangement creates several restrictions for the surgeon. The instruments have only four degrees of freedom with a diminished tactile feedback. The visual display system only provides a two dimensional image which is captured from the operative field by an endo- scope. This image is remote from the location of motor control, where manipulations occur, and with the current design of theatre workspace, the visual axis of the sur- geon is not aligned with the motor axis of the instrument and forearm. In almost all surgical studies, surgical performance has been investigated in terms of the outcome and complica- tions that may arise as a result of surgical error (Cuschieri et al, 1991; Southern Surgeons Club, 1991; Airan et al, 1992; Schumpf, 1994). However, these morbidity data do not provide prescriptive information of how errors are enacted and cannot specify how the performance of a procedure can be improved. A detailed study of the errors is required to identify the performance shaping factors (PSFs) which underlie these errors, and their resultant surgical complications, inorder that corrective action to reduce the likelihood of recurrence can be taken. *Author to whom correspondence should be addressed The aim of this study was to identify the errors made by surgeons undertaking laparoscopic surgical proced- ures to direct more specific future research into the PSFs affecting surgical performance. Materials and methods The study of human error in industry has typically in- volved the use of simulation exercises to predict the occurrence of errors in real circumstances (Meister, 1992). However, any prediction study needs further validation by observation and collection of data from the workplace in order to confirm the accuracy of the prediction in reality. In this study, a modified human reliability assessment (HRA) approach was applied to evaluate task performance in minimal access surgery. HRA is the systematic assessment of human—machine systems for their potential to be affected by human error. The high level of motor control required for endoscopic manipulations was predicted to result in an error rate that would be recordable under a practical sampling regime. In addition, routine video recording of endo- scopic operations made it possible to obtain a source of observational data which could be used to assess surgical errors in the workplace without the need for prediction studies. Surgical procedure Laparoscopic cholecystectomy (removal of the gallblad- der) was selected as the surgical procedure for the study as it is the most commonly performed laparoscopic operation. The procedure involves removal of the 409