Comparison of electronically superpulsed and continuous-wave CO2 laser on the rat uterine horn.

Forty-three rats underwent a series of operations with the CO2 laser to incise the uterine horn. Electronically pulsed laser light was compared with the continuous-wave (CW) mode on alternative horns, with each animal serving as its own control. Five variations of the superpulsed mode were compared with the same number of CW settings. Three experiments were performed: acute evaluation after partial uterine horn transection, acute observation after complete transection, and chronic studies after partial transection. The sectioned uterine horns were grossly observed and photographed, then sampled, histologically fixed, and studied by light and scanning electron microscopy. Zones of thermal necrosis were measured by an imaging tube and quantified by a computer-linked digitizing tablet. The results of this study demonstrated 2.5 times less thermal necrosis by electronically pulsed, versus the CW, laser beam. Four-and-one-half times less necrosis was also observed when the pulsed laser was employed for complete transection experiments. Adhesions were provoked in every animal that underwent chronic investigation. Inflammatory response, adhesion progression, and hydrosalpinx formation were significantly diminished in the pulsed-treated group. Qualitatively, wounds inflicted by pulsing showed different geometric patterns, compared with CW incisions. Electronic pulsing offers the surgeon the combined advantages of knife-like incisions and the precision and hemostatic properties of the CO2 laser.