Flow-through flap with wrist epithelial branch of ulnar artery for repair of finger soft tissue defect: a case series

Objective: To evaluate the surgical technique and the efficacy of flow-through flap with a wrist epithelial branch of the ulnar artery to repair a finger soft tissue defect. Methods: Between June 2015 and December 2017, 12 cases of soft tissue defects of fingers and injured digital artery were repaired by flow-through flap with wrist epithelial branch of the ulnar artery, including 7 males and 5 females (age range: 18-45 years old, average age: 23.6 years old). The causes of injury included electric saw injury in 7 cases, and machine crush injury in 5 cases. 5 cases were combined with tendon injury, 4 cases with fracture, 12 cases with vessel injury and 2 cases with nerve injury. The area range of the flap was 3.0 cm x1.8 cm to 6.0 cm x3.0 cm. The length of the pedicles of the flaps ranged from 2.3 cm to 4.7 cm, with an average length of 3.7 cm. The donor sites were sutured directly in 10 cases, and 2 cases were repaired with a full-thickness skin graft from the ilioinguinal region. Flow-through anastomoses of the distal and proximal end of the wrist epithelial branch of the ulnar artery to the distal and proximal end of the digital artery were created, so as to connect the vessels and reach the physiologic state of blood supply. Results: All flaps and skin grafts survived after operation, and all wounds healed at I phase. All patients were followed up 6-12 months (mean: 9 months). The flaps exhibited smooth appearance and soft texture, similar to that of the normal surrounding skin. At last follow-up, the two-point distance of flaps was 9-15 mm (mean: 11 mm). According to the assessment of upper limb function issued by the Hand Surgery Society of Chinese Medical Association, the hand function was excellent in 10 cases, and good in 2 cases. The ulnar wrist donor areas only had linear scar. Conclusion: Flow-through flap with wrist epithelial branch of ulnar artery exhibits strength in a concealed donor site, reliable blood supply, and simple operation. Flow-through method can be used to repair a broken or defective digital artery in I stage. It is a good method to repair a soft tissue defect of fingers.