Digital Amputations

Updated: Oct 02, 2019
  • Author: Bradon J Wilhelmi, MD; Chief Editor: Vinod K Panchbhavi, MD, FACS  more...
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Overview

Background

An amputation is the removal of an extremity or appendage from the body. Amputations in the upper extremity can occur as a result of trauma, or they can be performed in the treatment of congenital or acquired conditions. Although successful replantation represents a technical triumph to the surgeon, the patient's best interests should direct the treatment of amputations.

The goals involved in the treatment of amputations of the upper extremity include the following [1, 2] :

  • Preservation of functional length
  • Durable coverage
  • Preservation of useful sensibility
  • Prevention of symptomatic neuromas
  • Prevention of adjacent joint contractures
  • Early return to work
  • Early prosthetic fitting

These goals apply differently to different levels of amputation.

Treatment of amputations can be challenging and rewarding. It is imperative that the surgeon treat the patient with the ultimate goal of optimizing function and rehabilitation and not become absorbed in the enthusiasm of the technical challenge of the replantation, which could result in poorer outcome and greater financial cost due to lost wages, hospitalization, and therapy.

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Indications

Amputations can result from traumatic injury involving a variety of machines, they can be self-inflicted, or they may be required after traumatic events, such as electrical burns or frostbite. In addition, elective amputations may be indicated for tumor extirpation, vascular insufficiency, infection, or congenital malformation.

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Technical Considerations

Anatomy

The basic skeleton of the wrist and hand comprises a total of 27 bones. The hand is innervated by three nerves—the median, ulnar, and radial nerves—each of which has sensory and motor components. The muscles of the hand are divided into intrinsic and extrinsic groups.

The hand contains five metacarpal bones. Each metacarpal is characterized as having a base, a shaft, a neck, and a head. The first metacarpal bone (thumb) is the shortest and most mobile. It articulates proximally with the trapezium. The other four metacarpals articulate with the trapezoid, capitate, and hamate at the base. Each metacarpal head articulates distally with the proximal phalanges of each digit.

The hand contains 14 phalanges. Each digit contains three phalanges (proximal, middle, and distal), except for the thumb, which only has two phalanges. To avoid confusion, each digit is referred to by its name (thumb, index, long, ring, and small) rather than by number.

Important anatomy to understand in performing digital amputations includes the various structures of the digit, such as the digital nerves, the digital arteries, the flexor digitorum profundus (FDP), the flexor digitorum superficialis (FDS), the extensor tendons, the collateral ligaments, the volar plate, the dorsal capsule, and the components of the nail. When amputations are performed at various levels, it is important to understand the critical anatomy to optimizing resultant function.

For amputations at the distal interphalangeal (DIP) level, volarly the FDP is severed and allowed to retract proximally. The digital neurovascular bundles can be found on the radial and ulnar border of the distal digit at the DIP crease to be at the level of their trifurcation. These neurovascular bundles course between the Grayson and Cleland ligaments volarly and dorsally, respectively.

The digital nerves are longitudinally retracted and severed to allow retraction (so-called traction neurectomy) to prevent neuroma formation at the tip. The digital arteries are bipolar-coagulated to minimize bleeding. These neurovascular structures can be located longitudinally along this vector throughout the digit between the Grayson and Cleland ligaments. Each joint is stabilized by the radial and ulnar collateral ligaments, and the volar plate and dorsal capsule may require severing to detach the adjacent phalanx.

For more information about the relevant anatomy, see Hand Anatomy.

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Outcomes

Charpentier et al retrospectively evaluated long-term quality of life and functional outcome in 28 patients who underwent digital replantation after amputation after a minimum follow-up of 2 years (mean, 4.6). [3]  Total active range of motion (ROM), grip, and pinch strength were assessed; functional outcomes were evaluated; and occupational status and daily activities were reported. Mean total active ROM was 42% of the contralateral healthy side. Mean grip and pinch strength were 80% and 65%, respectively. Fusion did not significantly influence active mobility. Of the 28 patients, 77% returned to the same job, and 75% experienced cold intolerance.

Lafosse et al retrospectively studied surgical outcomes in 13 very young children (mean age, 2.9 years; range, 1.1-5.7) who underwent finger replantation (15 fingers) after traumatic amputation. [4]  The authors evaluated everyday life activities, pain and cold tolerance, total active ROM in patients with successful replantation, and growth disturbance. The overall success rate was 47%, with a 67% rate of major complications. Venous ischemia developed in 86%. The hemoglobin level decreased by more than 2 g/dL in six patients, and blood transfusion was necessary in two patients. At the last follow-up, patients with successful replantation had a mean total active ROM of 72%.

Shaterian et al performed a quantitative review and meta-analysis of 36 studies with the aim of identifying predictors of digit survival following replantation. [5]  Factors found to influence replant survival included number of venous anastomoses (zero vs one vs two), number of arterial anastomoses (zero vs one vs two), and mechanism of injury (sharp cut vs blunt cut vs avulsion vs crush). Factors not found to be significantly associated with survival included age, sex, zone of injury, digit number, tobacco use, ischemia time, method of preservation, and use of vein graft.

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