A modified procedure for replantation of severed digit-tips in Tamai zones I - II and the clinical effects / 中华显微外科杂志

ABSTRACT

Objective:To explore the clinical effect of a modified surgical procedure for replantation of severed digit-tips in Tamai zones I-II.Methods:From November 2019 to October 2022, the Department of Hand and Foot Microsurgery of the First Affiliated Hospital of Bengbu Medical College employed a modified procedure (to abandon the anatomically labelling of blood vessels and nerves after naked-eye debridement and fracture fixation, then perform the microscopic dissections and anastomoses of blood vessels and nerves, and the anastomosis of dorsal veins though an auxiliary small incision by the lateral nail fold of the severed digit-tip) to replant severed digit-tips in Tamai zones I-II of 26 patients (29 digits). The patients were 20 males (23 digits) and 6 females (6 digits), aged 3-66 years old, with mean age at 28 years old. Nineteen digit-tips were severed in Tamai zone I and 10 in Tamai zone II. The severed digit-tips were 7 of thumbs, 9 of index fingers, 5 of middle fingers, 5 of ring fingers and 3 of little fingers. Causes of injury were 12 of cut, 8 of crush and 6 of avulsion. Postoperative management included infection prevention, antispasmodic for 3 days and keeping in bed for 5 days. The time of surgery was recorded on all patients. Postoperative follow-ups were conducted at outpatient clinics for 6 to 12 months to observe the survival of digit-tips and the appearance, recovery of sensation and motor functions, strength of digits and patient satisfaction.Results:(1)The surgical time was about 1.0 hour for replantation of a severed digit-tip in Tamai zone I, while it took about 1.5 hours for those in Tamai zone II. (2)Survival rate and appearance: all 29 replanted digit-tips survived, except 2 in Tamai zone I which encountered venous occlusion and survived after small incision for bloodletting. Twenty-two digit-tips gained pulp fat pads with full digit pulps. Four avulsed digit-tips had mild atrophy of pulp. The 15 digit-tips severed in Tamai zone I were about 2 mm shorter than the healthy sides, but without deformity. One digit-tip had poor nail appearance due to preoperative fungal infection of nail bed. (3)Sensory recovery: with the British Medical Research Council (BMRC), 23 digit-tips recovered to S 3+, and 2 digit-tips of avulsion and 1 digit-tip of crush recovered to S 3. TPD of the replanted digit-tips were: 4-7 mm in those of cut injury; 6-8 mm in those of crush and 9-11 mm in those of avulsion. (4)Motion and digit strength: results of functional assessment according to the total active mobility standard promoted by China's Society for Surgery of the Hand were: 21 cases of excellent and 5 of good, without pain in digit pulp when pinching and griping. The mobility of the digits with replanted digit-tips of both Tamai zones I and II were close to that of the healthy sides. The motions of the digits with replanted digit-tips in Tamai zone I were close to the healthy sides and the 5 of those in Tamai zone II had 0° in extension and 2°-3° in flexion, due to the severed plane at distal interphalangeal joint. (5)Patient satisfaction: 25 patients were satisfied, however 1 patient was dissatisfied to the poor function of the distal interphalangeal joint due to the severed thumb-tip in Tamai zone II. Conclusion:Modified replantation procedure for severed digit-tip in Tamai zones I-II has significant achievement in cutting down the surgical time through a modified procedure of debridement and fracture fixation (tendon suture) by naked-eyes operation first, followed by dissections and anastomoses of the blood vessels and nerves under the surgical microscope. The auxiliary small incision by the lateral nail fold of digit-tip in Tamai zone I facilitates an exposure of a constant, healthy lateral nail fold vein. It enables the anastomosis with a high-quality vein, hence improves the success rate of replantation. The appearance and function of the replanted digit-tip are found better in the severed digit-tips of cut injury than those with injuries of avulsion and crush.