[Gas-no touch-enucleation].

The gas not touch enucleation procedure described in the present paper was prompted by Zimmerman's theory that the increase in the rate of metastasization following enucleation of eyes with melanomas is due to intraoperative fluctuations in IOP. Prior to surgery the blood circulation in the affected eye is interrupted by a kind of "invisible hemostatic clamp ab interno." In practice this is accomplished by an intravitreal gas injection. From July 1984 to December 1987 this technique was used in 22 enucleations performed because of large choroidal melanomas. The average base diameter of the (histologically verified) tumors was 15.1 mm and their height 9.9 mm. In each of 11 patients air or an expanding perfluorocarbon gas (4 x CF4, 4 x C2F6, 3 x C3F8) was injected through a 30-gauge needle via the pars plana. IOP was subsequently maximally elevated, the eye "rock hard," the central artery not perfused, and the entire blood circulation in the affected eye interrupted. The volume of gas injected ranged from 0.8 to 2.2 ml (average 1.4 ml). IOP remained maximally elevated throughout the enucleation procedure, even persisting in the enucleated eye. No special instruments are needed for gas no touch enucleation, it is easy to perform and the duration of surgery is not increased. It can be performed by any eye surgeon in any operating room when an eye with a malignant melanoma has to be "no touch" enucleated, i.e., avoiding fluctuations in IOP in order to minimize the chances of tumor cell seeding into the bloodstream. For "no touch" enucleations the gas technique thus represents a viable alternative to Fraunfelder's freezing technique.