|Microsurgery: Transplantation and Replantation by Harry J. Buncke, MD, et al.|
| These are available in many sizes and shapes, with curved or straight jaws, curved or flat jaw surfaces, arid with or without locking mechanisms. Surgeon preference and the specific conditions of the anastomosis dictate the choice of holders. Most surgeons prefer nonlocking needle holders because the maneuvers required to unlock the jaws cause sudden displacement of the instrument tip, which may tear or increase the size of the needle hole in the vessel wall. Remote control hydraulic, magnetic, and mechanical release mechanisms have been described, but are not popular because of their complexity and their maintenance problems. They have a place in certain situations, however, when finger manipulation is difficult.
Sutures are usually made of monofilament nylon and come in a variety of needle sizes23 and suture weight: from 9-0 with a 150 micron needle to 11-0 with a 50 micron needle. We recommend 9-0 sutures for vessels and nerves proximal to the wrist, 10-0 for hand and proximal digital vessels, and 11-0 for distal digital vessels and small nerves.
Patient Evaluation and Management
Stabilizing vital signs and preserving life are of primary importance in any trauma patient. When the patient is stabilized and no contraindications for replantation have been found, attention should be given to the injured part and reducing ischemia time. Acceptable ischemic times vary, but excessive ischemia may dictate amputation rather than replantation. For total amputations, single or multiple, ischemic time is measured from the time of injury until the time of revascularization of each structure. Warm ischemia time should not exceed 10 hours in digits and 6 hours in limbs. Cooled digits have been replanted up to 48 hours after amputation. The more muscle in the amputated part, the shorter the warm or cold ischemia time. Cooling the amputated part is therefore vital; adequate cooling increases acceptable ischemic time and reduces the rate of catabolism and the production of toxic breakdown products. With subtotal amputations, cooling the devascularized part may be difficult because cooling sensate areas adds to the patient's discomfort and increases vascular spasm. If possible, however, plastic bags filled with ice can be gently placed above and below the devascularized limb.
There are two techniques for preserving a severed part.2,14
1. Wrap the part in gauze moistened with saline or Ringer's solution and place it in a sealed plastic bag, which is then placed on ice. 2. Immerse the part in saline or Ringer's solution in a plastic bag, which is then placed on ice.
Although problems with these techniques seem to be rare,2 immersion may cause maceration of the preserved part, and the gauze-wrap technique may cause freezing or strangulation.
Once in the replant center's emergency room, the patient is resuscitated with IV fluids and treated with IV antibiotics and tetanus toxoid, and x rays and laboratory studies are performed. One team of microsurgeons evaluates the patient and prepares him or her for surgery; another team takes the amputated part to the operating room for evaluation.
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