|Microsurgery: Transplantation and Replantation by Harry J. Buncke, MD, et al.|
| Leeches are used only for a single application. Once applied, the leech is left undisturbed until it detaches voluntarily to minimize the possibility of infection from the regurgitation of gut contents.
Application of Leeches
It is important to use a leech that is exhibiting feeding behavior to ensure that leeching will be successful. Thin, active leeches are more likely to attach more eagerly. If the leech does not readily attach and adequate arterial circulation is present, a different leech should be tried. If a leech is used immediately after surgery, it may stop feeding because of absorption of anesthetic agents. The leech should therefore be reapplied at a later time to be effective.
The congested flap or digit should be cleaned to remove any ointment, skin antiseptics, or old blood. The desired area of attachment is then surrounded with gauze to inhibit the leech from moving to another area. Alternatively, a plastic sheet (Op Site*) can be applied and a hole made where the leech is to be attached. A pinprick is made in the skin and some blood expressed. To limit trauma to the tip of a replanted digit, a portion of the nail plate may be removed and the exposed nail bed used as the attachment site. A drop of 5% glucose (D5W) is then placed on the wound, and the narrow end of the leech applied to the blood and glucose droplet. The use of disposable gloves and gentle handling with forceps reduces the possibility of the leech being injured or attaching to the applier's hand. Once the leech has begun feeding, it should be left undisturbed until it becomes engorged, at which time it will fall off or may be removed by stroking it with an alcohol or saline swab.
Maintaining leeches is fairly simple. They should be kept in a Bell jar filled with spring water (or distilled water treated with HIRUDOSALT**) and capped with a nylon stocking cover, held with a sturdy elastic band and placed in a refrigerator, where the cold temperature decreases their activity and the need for feeding for several months. The water may require changing every few weeks if it becomes cloudy, but this requirement varies with the density of the leech population it supports.20 Commercial suppliers of leeches can provide detailed instructions for leech care and maintenance.
* Op Site. Acme United Corporation, Bridgeport, Connecticut. * * Leeches U.S.A., Ltd., Westbury, New York.
FIG. 40-01. The medicinal leech (Hirudo medicinalis) has been effective in our unit in salvaging replanted tissue.
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