Tian-Hao Zhang

Replantation of Severed Fingers with Soft-Tissue Defects

With the development of industry and agriculture, and diversification of the automatic machine, there are and increasing number of types of severed fingers including those with soft-tissue defects. Soft-tissue defects include defect of the skin, vessels, and nerves, and there is a lack of a regular method for repair because of the complicated conditions, the variety of injuries, and variety of ways to repair them. Professional microsurgical techniques and a knowledge of flaps are required for surgeons so that they choose a suitable flap for repair according to the type of injury and the extent, position, and scope of the defect. Soft-tissue defect was listed as a contraindication for replantation in the 1980s. The replantation used to be applied by shortening bones that would survive, but without satisfactory appearance and function. Sometimes, to preserve the joints and length of the fingers, palliative debridement may cause infection, necrosis of the skin, and poor blood supply, which will affect finger survival or the finger survives, but the functioning is affected by the shortened finger, poor sensation, severe tendon adhesion, and stiff joints. With the development of microsurgery techniques and the maturity of flaps, vessels, tendons, flaps, and composite tissue flaps can be used to repair the soft-tissue defects of severed fingers to reduce postoperative vascular crisis, increase the survival rate, and expand the indications for replantation.

Replantation of Amputated Tissue Mass of Fingers

With amputated tissue mass of fingers, some parts’ continuity with the finger body is broken, including bones, joints, tendons, vessels, and nerves, which cannot survive without vascular anastomosis. It is different from general replantation of severed fingers in these respects: n n(a) n nThe tissues are usually separate from each other. n n n n n(b) n nNo well-known vessels or nerves to be matched or just pass away. n n n n n(c) n nThey are difficult to replant and microsurgical techniques are required because the anatomy of the amputated tissues is not clear, but the appearance and functioning will be good if the surgery succeeds.

Transpositional Replantation of Severed Fingers

Transpositional replantation is also known as ectopic replantation, when the hand suffers severe trauma, the digital body, such as the palm and fingers, is partially preserved relatively intact, but without being able to undergo in situ replantation. To restore the function of the hand as far as possible, make use of the severed fingers, and, according to the function, of the need to shift the area. The relatively minor finger is shifted to a relatively important position or to reconstruct a hand shape in a proximal limb. Reconstructing the hand function and utility avoids a second-stage operation and reduces the patient’s pain and burden.

Replantation of Severed Fingers in Children

The technology of the replantation of severed fingers makes it possible to achieve normal limb morphology and functional recovery through precise microvascular anastomosis, and sufficient repair of bone, tendons, the skin, and nerves. In 1964, Malt and McKhann reported that they preserved a 12-year-old boy’s upper arm in May 1962. In 1963, Kleinert et al. (1963) first reconstructed the blood supply of the thumb by means of arterial anastomosis. In 1965, Komatsu and Tamai (1968) successfully completed the replantation of the first complete amputation of a finger. In 1974, Tamai performed a successful replantation of the left proximal interphalangeal joint of a little finger that had been completely cut off in a 20-month-old child. At that time, Tamai anastomosed the finger artery and finger nerve with the help of a microscope and obtained good clinical results. In 1980, Cheng Guoliang et al. (1998) reported a case of a 45-month-old child in whom 2–5 fingers on the left hand had been completely cut off. All the fingers survived after replantation. In 1980, Wang Chengqi et al. reported a successful case of a 25-month-old child with 2–5 fingers completely severed from the left hand, in which the index and middle fingers were shifted with the middle and ring fingers. In 1982, Cheng Guoliang et al. (1982) reported a 9- to 15-year follow-up study of 26 cases with 45 replanted fingers and found that the postoperative excellent and good rate was 100%. This study truthfully reflected the level of severed finger replantation in children in our country, which has leapt up to the world’s advanced level in a short period of time. However, compared with adults, replantation of severed fingers in children still has its peculiarities: n n1. n nThe finger blood vessel is small and anastomosis is very difficult. n n n n n2. n nChildren’s mental development is not complete; thus, they cannot fully cooperate with the treatment after the operation. n n n n n3. n nLimitations of drug use n nThe development of the surgical microscope, fine microsurgical instruments, and microsuture hardware laid the foundations for the replantation of severed fingers in children up to the 1970s.

Common Medicines Used after the Replantation of Amputated Fingers

The successful replantation of amputated fingers is based on not only the microsurgery technique, but also the medicines used postoperatively. Three kinds of medicines are generally used after an operation, which are antibiotics, antispasmodics, and anticoagulant drugs. Antibiotics must be used intraoperatively and postoperatively because of complex injuries, the long duration, and prolonged exposure of the wound. The common reasons why the antispasmodic drugs and anticoagulant drugs should be used after an operation are: n n1. n nBlood coagulability is increased after injury and operation, which is the body’s protective physiological response n n n n n2. n nAdrenaline is released after the injury and operation; thus, patients are prone to experiencing vasospasm, an increase in platelets and an increase in blood coagulation, which easily leads to thrombosis n n n n n3. n nSpasticity and thrombosis can be easily induced because of the small diameter, which is commonly 1–3 mm (a minimum of 0.2–0.5 mm), and easy susceptibility to physicochemical factors n n n n n4. n nThere is a higher chance of thrombosis because of the small scouring force to anastomotic stoma caused by the small diameter and low blood flow. It is necessary to use antispasmodic drugs and anticoagulant drugs because experiments have proved that the smaller diameter of the vessel, the more likely it is that thrombosis will occur, because the 1-mm vessel has a platelet absorption density twice as high as the 2-mm vessel. In Table 4.1, the commonly used drugs are shown.

Replantation of Severed Fingers in the Elderly

The replantation of severed fingers of old people relates to those whose over 60 years old. With the development of basic and clinical research, age is no longer a contraindication. If old people suffer severed fingers, their general condition should be assessed first to judge whether they can tolerate surgery, and then consideration should be given to whether or not they wish to undergo replantation and to ensure they understand the function of replanted finger. Any operative treatment should be considered on the assumption of a relatively good condition of the severed finger, short ischemia, good general condition, controlled internal diseases and expected good function recovery. The replantation of severed fingers of old people is always a challenge in clinical practice because of its specificity, but the age range of successful replantation is growing. There was successful case reported for a 72-year-old at No 153 Central Hospital of the People’s Liberation Army in 1990, and for a 74-year-old at No 89 Hospital of the People’ Liberation Army. Another successful case, for a 79-year-old, was described in Hand Surgery, edited by Gu Yudong, Wang Shuhuan and Shi De in 2000.

The History of the Replantation of Amputated Fingers

The hand is an organ related to labor and beauty that distinguishes humans from other animals. As human civilization progresses, the hands play an irreplaceable role in the process when human activities shift from handicraft to light industry, heavy industry, and electronic technology information. Hands are most susceptible to damage during daily life and work. During industrial production in particular, with relatively low automaticity, it is not uncommon for severe traumas caused by high energy in the hands to result in finger mutilation, leading to life-long disability. Surgeons face the arduous task of attempting to repair and reconstruct the injuries, reduce the patient’s disability and improve their quality of life. Human efforts to carry out studies of hand trauma have never ceased, whether the study be fundamental or clinical. The simple trauma care of hand injuries has been directed to evolve toward the complicated replantation of mutilated fingers and the recovery of hand functions. Long-term clinical practice has demonstrated that patient cooperation and reasonable functional exercise is also of vital significance during the treatment of hand trauma, in addition to the doctor’s accurate judgment, skill proficiency, and proper management. Satisfying results can be achieved in the recovery of hand trauma only after the joint efforts of both doctors and patients.

Replantation of the Final Segment of the Finger (Finger Tip)

The final segment of the finger is the furthest structure of the hand, the most frequently used in daily life, and has the highest rate of injury; thus, replantation of the final segment of the finger (fingertip) is common. The functioning of the finger will be seriously affected if the final segment is missing, even though it is small. Compared with the flap method of retaining the length of the finger, replantation is irreplaceable in the recovery of appearance, movement, and feeling. In principle, if the systemic condition of the patients permitted it, if the structure of the severed finger was more or less complete, and if patients and their families required replantation, replantation should be chosen whenever possible.

Late Replantation of Severed Fingers

Severed tissues should be replanted within 6 h at room temperature (20–25 °C), as irreversible necrosis of the muscles occurs because of ischemia. The time can be increased to 12 h if refrigerated (4 °C). The ischemia time for fingers without muscles could be 8 h at room temperature and 12 h under refrigeration. The replantation of a finger whose warm ischemia time is over the time limit is called late replantation. There are very few successful reports of late replantation, and most of these are case reports.

Replantation of Severed Fingers with Avulsion

Severed finger with avulsion is also called a ring avulsed finger that is combined with avulsed arteries and nerves, which are difficult to repair. It usually occurs in workers wearing gloves to operate a high-speed spinning machine or a finger with a ring whose entire soft tissue was avulsed like taking off the gloves, including skin, subcutaneous tissue, vessels, and nerves, just leaving the bones, joints, and tendons. It is characterized by: n n(a) n nThe destroyed finger has a blunt injury, which is much heavier than the distal part. n n n n n(b) n nThe avulsed tissues are not in the same plane or even the same tissue. n n n n n(c) n nThe avulsed vessels and nerves are usually long and may not be able to be used. n n n n n(d) n nThe finger body of the destroyed finger is usually contused to different degrees.