Abstracts
1997 Digestive Disease Week

Laparoscopic colon surgery is less stressful than conventional colon surgery.

PE Marchesa, JW Milsom, A Vignali, A Vladisavjevic, S Dei, L Rybicki, VW Fazio. Departments of Colorectal Surgery and Biostatistics, The Cleveland Clinic Foundation, Cleveland OH.

Background: Circadian rhythm (CR) disruption may be one of the most sensitive indicators of degree of stress after events such as surgery. Aim: To compare the disturbances of preoperative motor activity, body temperature, and heart rate CR following laparoscopic vs conventional right hemicolectomy in a canine model. Material and methods: Male beagle dogs (n=24; age 7-8 months) were kept under highly controlled photo-periodic conditions (12 h light and 12 h dark) in a sound-attenuated room. All dogs carried a data acquisition system able to simultaneously record loco-motor activity, EKG, and body temperature 23 hours/day. CR periodicity of these parameters was studied using TAU^TM analysis software (Minimitter Co SunRiver OR). Data were downloaded daily to a personal computer, collected for a mean of 7.5 days preop and 9 days postop. Dogs underwent laparoscopic (Lap, n=12) or conventional (Conv, n=12)^- right hemicolectomy. Enright's periodogram was used to determine existence of circadian cycles. ANOVA and paired t-tests were also used. Results: 19 dogs (laparoscopic n=9, conventional n=10) were studied. 5 dogs were excluded due to hypothermic (n=2), surgical (volvulus n=2), or recording (n=1) complications. In the preop period there were no statistical differences between groups for loco-motor activity, EKG, and body temperature (p=0.56, 0.65, 0.45; respectively). The following reports the duration (hours) and changes in CR periodicity over the study period.

   Variable     Group     Pre-op     Post-op    Variance    p-value
 Temperature    Conv     24.4(1.1)  23.4(0.7)   -1.0(1.4)    0.06
 ( ) = SD       Lap      23.6(1.0)  23.5(0.7)   -0.1(0.9)    0.78
 Heart Rate     Conv     24.4(0.7)  23.6(0.7)   -0.7(0.7)    0.006*
                Lap      23.6(0.5)  23.3(0.3)   -0.3(0.6)    0.21
 Locomotor      Conv     24.4(0.8)  25.3(0.6)   1.0(1.1)     0.021*
                Lap      24.0(0.6)  24.3(0.6)   0.3(0.6)     0.2

There were no differences in the pre vs. postop CRs in the laparoscopic group in any parameter. In the conventional group, heart rate and locomotor activity circadian periodicities were significantly altered postoperatively and temperature almost reached statistical significance (p=0.06). Conclusions: Under highly controlled circumstances biological circadian periodicity was preserved after laparoscopic but not after conventional colon surgery in a dog model. Our findings support the hypothesis that laparoscopic colon surgery is overall less stressful. (This research was funded in part by U.S. Surgical Corporation, Norwalk, CT).