In-line image projection accelerates task performance in laparoscopic appendectomy

Background: In laparoscopy, the monitor usually is placed at or above eye level across from the operating surgeon. Position of the endoscopic image at hand level has been shown in a laboratory model to facilitate task performance. The authors tested the hypothesis that in-line image projection reduced operating time for a standardized procedure. Methods: Children undergoing laparoscopic appendectomy were assigned randomly according to video image position: (1) at the top of the laparoscopy tower in front of the surgeon ("overhead") or (2) on a screen placed on the patient's abdomen ("in-line"). Operating time was recorded for each operation, and patients were stratified according to severity of appendicitis and training level of the operating surgeon. Statistical analysis was performed using Student's t, χ² tests, and analysis of variance with post-hoc Fisher test (P < .05. significant). Results: One hundred eight children, aged 2 to 17 years, underwent a laparoscopic appendectomy during a 26-month period. Fifty-four were assigned to the in-line projection screen and 54 to the overhead monitor. Operating time was significantly shorter (P = .013) when in-line projection was used (46.8 ± 10.2 v. 52.2 ± 15.1 minutes with overhead monitor). By analysis of variance (ANOVA) the only factors that significantly affected operating time were use of in-line projection (P = .030), severity of appendicitis (P = .002), and training level of the operating surgeon (P = .047). Conclusions: Placing the endoscopic image in the same field as the surgeon's hands decreases operating time by 10%, even for procedures that, like appendectomy, do not require complex suturing skills. This decrease in operating time occurs independently of the surgeon's level of proficiency or the degree of difficulty of the operation.