Efficacy of electrocautery in different media: air, perfluorodecalin, glycerine, glycine, and electrolyte solution

Electrocautery during fetoscopic surgery is impossible in the electrolyte-containing amniotic fluid. Intrauterine insufflation of carbon dioxide may cause lethal hypercapnia and acidosis in the fetus. Therefore, other media must be considered.

To evaluate the efficacy of electrocautery in different media that have been described for fetoscopic surgery.

Using bipolar electrocautery, lesions were made in 16 skin/cartilage specimens from the ears of New Zealand White rabbits in 5 different media: air, 85% glycerine, 1.5% glycine, electrolyte solution, and perfluorodecalin. The efficacy of electrocautery in the different media was compared by calculating mean necrosis indices--the quotient of native to necrosed tissue thickness--and assessing the qualitative histologic changes.

In all media except the electrolyte solution, the cauterized areas showed clear sequellae of electrocautery such as thinning, loss of tissue architecture, increased stromal staining, and nuclear disintegration. Mean necrosis indices were 1.38 +/- 0.24 for air, 1.37 +/- 0.28 for glycerine, 1.32 +/- 0.23 for perfluorodecalin, 1.31 +/- 0.14 for glycine, and 1.05 +/- 0.10 for electrolyte solution (P < 0.01 for electrolyte solution compared to all other media). No significant differences were detected between the nonconductive substances.

In our tests, air, glycine, glycerine, and perfluorodecalin allowed similarly effective electrocauterization. As expected, bipolar electrocautery in electrolyte solution is ineffective. The perfluorocarbon perfluorodecalin may have other potential advantages as a medium in endosurgery, such as low surface tension, biologic inertia, optical clarity, and insolubility of blood.