INFLUENCE OF PULSED ELECTROMAGNETIC-FIELDS ON HEALING OF EXPERIMENTALCOLONIC ANASTOMOSIS

PURPOSE: The study investigated the influence of pulsed electromagneti c fields (PEMFs) on the mechanical strength and collagen content of un complicated colonic anastomosis in rats. METHODS: A standardized left colonic resection was performed 3 cm above the peritoneal reflection, and end-to-end anastomosis was constructed with eight interrupted inve rting sutures. Beginning immediately after surgery, randomly assigned groups were exposed to one of the following: 1) 100 Hz (frequency), 1 mT (intensity) PEMFs with 16-hour on/8-hour off cycles (n = 8); 2) 100 Hz, 2 mT PEMFs with 16-hour on/8-hour off cycles (n = 8); 3) 100 Hz, 1 mT PEMFs with 6-hour on/6-hour off cycles (n = 6), whereas the contr ol group (n = 10) received no PEMFs. Relaparatomy was performed at 72 hours postoperatively, and the bursting pressure of the anastomotic se gment was recorded in situ. The hydroxyproline contents of the anastom otic and adjacent perianastomotic segments of equal lengths were deter mined. RESULTS: Mean bursting pressure values of the groups that recei ved 100 Hz, 1 or 2 mT PEMFs with 16-hour on/8-hour off cycles (90.88 /- 19.13 and 83.88 +/- 7.08 mmHg, respectively) were significantly hig her than those of the control group (61.66 +/- 10.6 mmHg) and the grou p with 6-hour on/6-hour off cycles (64.83 +/- 7.36 mmHg; P < 0.05 for all comparisons). Hydroxyproline contents of the anastomotic and peria nastomotic segments were consistently higher in the 16-hour on/8-hour off PEMF groups, compared with those of the corresponding segments of the control group. CONCLUSIONS: PEMFs applied externally to unrestrain ed rats within a ''window of PEMF parameters'' provided a significant gain in the mechanical strength of the colonic anastomosis, at least 7 2 hours postoperatively. Associated relative increases in the hydroxyp roline contents of the (peri)anastomotic colonic segments suggest that an altered collagen metabolism might contribute to this enhancement o f the anastomotic repair. Further investigations based on these prelim inary data and the definition of the exact measures regarding the effe cts of PEMFs on biologic systems, in general, may lead to an efficient and new adjunctive modality in colorectal surgery.