Upon the same principle into larger n evi a number of punctures may be made by a fine thermo- or electro-cautery. Paquelin's instrument is the best appliance for this purpose, and if skilfully used little deformity follows.
Electrolysis is often the only successful method of dealing with large subcutaneous or mixed facial mcvi. It may be used for minute mevi also, in which case the one-polar plan may be resorted to as in the removal of superfluous hairs. The anode being placed on the sternum or neck, the current from 4 to 6 small portable cells is turned on. A fine platinum needle mounted on a handle is attached to the kathode and thrust into the nevus, and permitted to remain till the discoloration spreads from the puncture for about inch, after which the cells should be cut off seriatim before withdrawing the needle.
This plan suits well for " spider " or small stellate nevi.
For all facia] nevi inch in diameter the bipolar method must be employed, and large Bunsen's cells (4 to 6) should be used. Both needles are thrust into the nmvus, the one attached to the positive pole being kept stationary, whilst the negative is moved from one portion of the growth to the other before the needle is withdrawn, in order to cause coagulation of blood and sealing up of the vessels. When the growth is large, a number of sittings may be necessary, the nevus being dealt with in detachments. Skill and experience are required to determine the duration of the elec trolysis; the contents of the growth become discoloured or livid around the frothing negative, while at the positive electrode the tissues become firm and bleached.
By employing the bipolar needle-holder of Lewis Jones, in which several parallel needles are attached alternately to each pole, a much more uniform and satisfactory result is obtainable, and a fair-sized nmvus may be destroyed at a single sitting of about 20 minutes, little scarring being liable to follow, if the needles be only partially withdrawn and moved about so as to reach the different parts of the growth without making unnecessary puncture marks.
Chloroform anaesthesia is necessary, as the operation causes a consider able amount of pain, and before inserting the needles the skin should be thoroughly sterilised. After the withdrawal of the electrodes a dry sterilised gauze pad should be bound over the site of operation by strips of adhesive plaster or by painting with flexible collodion.
Bleeding at the punctures is easily prevented by slowly withdrawing the electrodes before shutting off the current. Where the entire nievus cannot be operated upon at a single sitting, an interval of about four weeks may he permitted before the next insertion of the needles, but as cicatrisation goes on slowly a longer interval should elapse between subsequent applications.
Cirsoid aneurisms or arterial angiomata of the scalp, when small, may also be treated successfully by the electrolytic method, if complete excision be not decided upon.
Cavernous Angiomata are best removed by a careful dissection after ligature of the main vessel supplying the growth.