No hand is so badly crippled that, if it is painless, has sensation, and strong prehension, it is [not] far better than any prosthesis. Norman Kirk, 1944 [5]

Dr. Kirk’s statement in 1944 is as true today as it was then. For the hand surgeon, limb salvage and hand preservation are common considerations, typically presenting after severe trauma. Salvage of a functional hand may require revascularization, nerve repair, skeletal fixation, tendon repair, and/or soft tissue coverage. The goal of these procedures is to restore a pain-free, sensate hand that is capable of some sort of prehension. It is important to consider the minimum requirement that can allow prehension. This is possible with a single movable digit and some sort of post. This could mean a preserved thumb and just enough residual hand (“mitten hand”) or a thumb post and (a) movable finger(s) that can oppose. Therefore, the greatest value is placed on thumb reconstruction, even if it requires replantation of a finger in the thumb position (Fig. 51.1) or pollicization of a neighboring digit (Fig. 51.2). The thumb’s importance is recognized by work-related injury compensation where 40 % of the hand function and 25 % of total body function is attributed to the thumb.

Reattachment or replantation of the amputated part(s) often provides the best available reconstructive option. Indications for replantation include the following [6]:

while contraindications include the following:

Digits are quite tolerant of ischemia with successful revascularization reported after 33 h of warm ischemia [7] and 94 h of cold ischemia [8]. To protect the amputated part (and prevent cold injury), it should be cleansed, wrapped in moist sterile gauze, and placed in a water and airtight bag or container, which is then placed on ice. The patient and amputated part should be transferred to a level-1 trauma center with microsurgical and hand surgery expertise. Even with sharp, guillotine amputations, there is a zone of injury and modest skeletal shortening facilitates reattachment. This can be achieved by joint fusion if the amputation transections a joint, which is relatively common (Fig. 51.3). Although crush and avulsion injuries can make reattachment more challenging, these are not absolute contraindications for replantation and the digits should be considered for reattachment, excluding other contraindications. The sequence of repair is determined surgeon preference. The author’s preference typically begins with skeletal fixation, followed by tendon preparation, arterial repair, nerve repair, tendon repair, vein repair, and (loose) skin approximation. The dressing and splint are kept bulky and non-constrictive and allow for examination of the digit. Monitoring the part can be a challenge, especially if the part becomes macerated [9].

Hand salvage and length preservation can make a tremendous difference in the patient’s final functional outcome. The use of spare parts for reattachment or soft tissue coverage as a fillet flap must be considered. Often the spare parts are ischemic and there will not be an opportunity for use beyond the initial operation. Again, the guiding principles are the restoration of prehension for hand injuries and maintaining length for more proximal injuries. One consideration, when using a fillet flap for residual limb coverage, is to include innervated skeletal muscle that can be used acutely for targeted muscle reinnervation for prosthetic control (Fig. 51.4). However, when considering the inclusion of muscle, one must consider the ischemia time of the tissue, as the metabolic demand of skeletal muscle is relatively high and, additionally, there may be a risk of myoglobinuria .

Digits threatened by vascular compromise can present significant difficulties, specifically with patient rehabilitation and disability (Fig. 51.5). Whether a single or multiple digits are to be amputated, an analysis of retained function must be made to employ the most appropriate surgical plan. Inevitably, any loss of tissue will lead to decreased function (most commonly grip strength). Interestingly, the level of amputation does not always correlate with patient disability [10]. However, it is important to recognize that amputation is irreversible. When in doubt, it is better to leave a digit that may offer some unforeseeable function as it can always be removed later with little morbidity.

A multitude of various surgical options exist for digital amputation, ranging from simple guillotine amputation to complex reconstruction and tissue transfers. Preservation of length, soft tissue coverage, and functional sensibility are the core concepts in digital and partial hand amputations [11–15]. Postoperatively, the residual finger and/or hand is often hypersensitive. Directed hand therapy is often helpful to “desensitize” the remaining digit(s). Cold intolerance is also common, especially, when the remaining tissues may have insufficient circulation. This can be debilitating, especially in colder climates. While cold intolerance subsides with time, many patients will struggle long term. Some individuals may find it necessary to change work and/or living environments to avoid exposure to cold [3].

It should be highlighted that the thumb receives special attention due to its functional importance. It is estimated that the thumb comprises 40–50 % of overall hand function. Every effort should be made preserve the thumb. When this is not possible, thumb reconstruction should be considered. Advanced reconstructive techniques such as pollicization of a neighboring digit and toe-to-thumb transfers, can be employed, if possible and appropriate, to regain function [16, 17].

Regarding digit amputation, classically, greater value is placed on the central digits (middle and ring finger) in comparison to the border digits (index and small finger). It is easier to compensate for the loss of a border digit both functionally and cosmetically. A three-finger hand can actually look remarkably normal (Fig. 51.2) and functionally compensated. However, the loss of hand span (width) does present a loss of pronosupination strength due to loss of the lever arm length [15]. Loss of a central digit leaves a gap in the hand that is very noticeable and presents a functional problem with use of the hand as a cup or scoop. Narrowing the resultant space after central digit loss can be accomplished by ray resection with intermetacarpal ligament repair (Fig. 51.6) or ray transposition as described by Carroll and others [18, 19].

Amputation at the level of the wrist causing loss of the entire hand significantly decreases the overall function of the upper extremity secondary to loss of grip and intrinsic function of the hand. Creating wrist-level prosthetics is difficult and options are limited. Every option to preserve the hand must be entertained.