I. History
A. Limb—The first successful limb replantation was done in Boston in 1962, when Malt and McKhann replanted the arm of a 12-year-old boy.
B. Forearm—Chen reported successful distal forearm replantation in 1963.
C. Thumb—In 1968, Komatsu and Tamai reported the first successful thumb replantation.
II. Indications and Contraindications
A. Absolute indications
1. Amputation of the thumb at any level
2. Amputation of multiple digits
3. Amputation through the palm
4. Wrist and forearm level amputations and those below the elbow
5. Any level amputation in a child
B. Relative indications
1. Amputation of individual digits distal to flexor digitorum sublimis (FDS) insertion
2. Ring avulsion injuries
3. Amputations through the elbow and above the elbow
4. Amputation of border digits (especially proximal to the FDS insertion)
*Amit Gupta, MD, FRCS, or the department with which he is affiliated has received miscellaneous nonincome support, comercially-derived honoraria, or other nonresearch-related funding and royalties from SBi, holds stock or stock options in SBi, and is a consultant for or an employee of SBi.
C. Absolute contraindications
1. Severely mangled parts
2. Amputations in patients with other serious injury or diseases
3. Amputations in patients with severe vascular disorders
4. Amputations with prolonged warm ischemia, especially for parts with large muscle content
D. Relative contraindications
1. Multiple-level amputations
2. Avulsion injuries
3. Amputations in psychiatric patients
4. Amputations in patients with other injuries
5. Prolonged warm ischemia (parts with little or no muscle)
III. Pediatric Replantations
A. Functional results—If replantation is successful, functional results are better in children than in adults. The reasons for this include:
1. Increased capacity for nerve regeneration
2. Better tendon gliding
3. Quicker bone healing
4. Enhanced ability to regain joint motion.
B. Pediatric replantation is more difficult than in adults.
C. Survival rate of replantation in children is 60% to 70%, which is lower than in adults.
D. One concern in children is the ability to maintain epiphyseal growth following replantation.
IV. Considerations by Level
A. Proximal to the elbow
1. Poor functional outcome in adults
2. Need for multiple procedures
3. Poor motor and sensory function return in the hand
4. Large amount of muscle content in the distal part, so myonecrosis and subsequent infection as well as metabolic changes in the body leading to renal failure are a real danger. Ischemia time must be watched carefully.
B. Proximal to the wrist
1. A large amount of muscle will be present in the distal part. Therefore, warm ischemia time is critical. (Once rigor mortis has set in, the limb is nonreplantable.)
2. Extensive and adequate debridement of the distal part is fundamental.
3. Bone shortening is useful.
4. Stable and quick osteosynthesis is required.
5. Arterial shunt to shorten ischemia time may be necessary.
6. Cooling of the distal part is helpful.
7. Perfusion of the distal part with venous blood or University of Wisconsin cold storage solution should be done.
8. Arterial repair is done first.
9. Veins should be allowed to bleed out to wash out lactic acid and other catabolic products.
10. Venous anastomosis should be performed quickly.
11. Sodium bicarbonate should be infused before venous anastomosis to raise the pH level in the acidotic part.
12. Do not neglect the venae comitantes because they may cause significant bleeding; they should be cauterized.
13. Monitor urine outflow and blood urea nitrogen.
14. Blood transfusion is almost always needed.
15. Multiple extensive fasciotomies may be required.
16. Antibiotic coverage—cephalosporin, aminoglycoside, and an anti-anaerobic are indicated if extensive muscle damage is present in the replanted part.
17. Nerves may be repaired primarily or tagged in superficial extra-anatomic positions for later repair or grafting.
18. Loose skin closure and meshed split-skin grafting are used.
19. Careful patient monitoring in the intensive care unit is essential.
20. The dressing should be changed within 48 hours with the patient under general anesthesia.
21. Do not use anticoagulants.
B. Distal forearm and wrist
1. The best functional results of limb replantation are obtained at the distal forearm level.
2. In addition to the obvious nerves, such as the median and ulnar nerves, the dorsal branch of the ulnar nerve as well as the radial sensory and palmar cutaneous nerves must be repaired.
3. Bone shortening
a. Bone shortening in the distal forearm level is beneficial.
b. Much less bone shortening is possible at the wrist level.
4. Partial or total wrist fusion can be performed primarily.
5. Order of repair:
a. Debridement
b. Stable osteosynthesis
c. Extensor tendons
d. One artery anastomosis to restore circulation
e. Four or five venous anastomoses
f. Flexor tendons
g. Second artery anastomosis
h. Nerve repairs
i. Fasciotomy and skin closure
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D. |
Proximal palm—The proximal palm area extends from the distal border of the palmar arches to the carpometacarpal joints. At this level, replantation gives good results. |
1. Bone shortening and plating is used.
2. Usually only the superficial arch is repaired.
3. The deep arch vessels, as well as the metacarpal arteries, should be secured to prevent bleeding.
4. Revascularization often requires branched vein grafts from the arch to the common digital arteries.
5. At least two or three dorsal veins are anastomosed.
6. Flexor and extensor tendons and all cut nerves (median, ulnar, dorsal sensory branch of ulnar and superficial radial nerve) are repaired.
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E. |
Midpalm—The midpalm area is between the metacarpophalangeal (MCP) joints and the distal border of the palmar arches. |
1. Repair of a single digital artery can restore blood supply to the adjacent digits.
2. The metacarpal can be shortened.
3. Malrotation of metacarpals is a problem.
4. Intrinsic muscles should be debrided to prevent infection.
5. Deep arch vessels must be cauterized.
6. Order of reconstruction:
a. Debridement, excision of intrinsic muscles, and deep vessel cauterization
b. Bone shortening and open reduction and internal fixation of metacarpals
c. Flexor and extensor tendon repairs
d. Dorsal vein repairs (as many as possible; clamp and cauterize other veins)
e. Common digital artery repairs
f. Nerve repairs
g. Skin closure
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F. |
Proximal interphalangeal (PIP) joint to MCP joint |
1. Results of replantation at this level are poor in adults because of tendon adhesions.
2. There is limited capacity for bone shortening.
3. Malrotation is a problem.
4. Flexion contracture of digits is a problem at the PIP and distal interphalangeal (DIP) joint levels.
5. Osteosynthesis with minimum hardware (interosseous wiring) is used.
6. Repair the extensor apparatus, including the central slip and lateral bands.
7. Repair at least two or three veins.
8. Secondary tenolysis and capsulotomy are necessary.
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G. |
PIP joint to DIP joint—With these amputations, the FDS, central slip of the extensor tendon, and the PIP joint are intact. Good function can be expected from replantation. |
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H. |
Thumb |
1. The thumb is the most important digit to replant because it provides 50% of hand function.
2. Replantation is indicated at all levels.
3. Ulnar digital artery is the vessel of choice for anastomosis.
4. A long vein graft may be applied from the distal ulnar digital artery and sutured end-to-side to the radial artery in the snuffbox or end-to-end to the princeps pollicis artery.
[
Table 1. Kay, Werntz, and Wolff Classification of Ring Avulsion Injuries]
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I. |
Ring avulsion injuries—Kay, Werntz, and Wolff developed a classification system for these injuries (Table 1). These are unique injuries with a predictable mechanism. Usually only one digit is involved and the injury is severe. |
1. Complete amputation is a relative contraindication to replantation.
2. Disruption of the venous drainage only is not a contraindication to replantation; combined arterial and venous injury without amputation is not a contraindication to revascularization.
V. Critical Points in Replantation
A. Preoperative evaluation should include:
1. General condition and stability of the patient—assess for multiple injuries
2. Level of injury and number of digits
3. Type of injury
4. Site of injury (eg, farm, factory)
5. Radiographic evaluation of the whole limb
6. Patient's occupation as it relates to functional needs
7. Patient and family expectations.
B. Preoperative treatment
1. The amputated part should be prepared before taking the patient to the operating room.
a. Should be debrided and the vessels identified and tagged
b. Should be kept cool
2. Fixation may be applied to the bone of the part to be replanted.
3. Vein graft may be attached to the part to be replanted if necessary.
C. Intraoperative evaluation
1. The vessels must be clean and not stretched or crushed.
2. Bone shortening will allow resection of damaged vessels and end-to-end anastomosis of arteries, veins, and nerves.
3. Vein grafting is used generously.
4. Tight skin closure is avoided.
D. Postoperative care
1. Keep the patient warm.
2. Keep blood pressure and urine output at adequate levels.
3. Monitor digital temperatures, capillary refill, and turgor of the finger pulps.
4. Leeches may help to improve venous outflow. If leeches are used, be alert for Aeromonas infection.
E. Pharmacologic supplementation
1. In clean amputations without technical problems:
a. Aspirin 81 mg/d
b. Dextran 40 (20 mL/h)
2. In crush injuries or if technical problems occurred during anastomosis, 1000 U/h of heparin should be administered intravenously for 5 to 7 days.
Top Testing Facts
1. The thumb (ulnar digital artery is the vessel of choice for anastomosis), hand, forearm, midpalm, and any level of amputation in a child are all replanted.
2. Prolonged warm ischemia is an absolute contraindication for replantation of major muscle-containing parts. (With rigor mortis, the limb is nonreplantable.)
3. In major limb replantations, repair the artery first and allow lactic acid washout from the limb before repairing the veins.
4. Distal forearm level replantation gives the best functional result of all levels of limb replantation.
5. Pharmacology: In clean amputations without technical problems, administer aspirin (81 mg/d) and dextran 40 (20 mL/h); in crush injuries or with technical problems in anastomosis, administer heparin intravenously (1000 U/h) for 5 to 7 days
6. The results of replantation at the level of the PIP joint to the MCP joint are poor in adults because of tendon adhesions.
7. Good function can be expected from replantation at the level of the PIP jiont to the DIP joint.
Bibliography
Askari M, Fisher C, Weniger FG, Bidic S, Lee WP: Anticoagulation therapy in microsurgery: A review. J Hand Surg [Am] 2006;31:836-846.
Kay S, Werntz J, Wolff TW: Ring avulsion injuries: Classification and prognosis. J Hand Surg [Am] 1989;14:204-213.
Pederson WC: Replantation. Plast Reconstr Surg 2001;107: 823-841.