Innervated Reverse Island Flap Based On The Dorsal Cutaneous Branch At Distal Interphalangeal Joint Of The Digital Artery

Fingertip or pulp defects, with the exposure of tendon orbone, represent a challenging reconstructive problem oforthopaedics. Appropriate therapy should maintain the normaldigital length, minimize the aesthetic deformity, preserve thefunction of nail and interphalangeal joints, and provide sensatesoft tissue covering without pain during use. Although there aremany methods for the problem , such as the advancement flap,the thenar flap , the cross-finger flap and reverse digital arteryflap et al, the results are not satisfactory.Of all the techniques, one-stage local island flaps arepreferred to multi-stage regional flaps because of shorterhospitalization, less cost, and minimal disability time of theinvolved finger. The one-stage vascular pedicle flap isbecoming increasingly popular. Till now all the vascular pedicleflaps are based on one digital artery. But reverse digital arteryflap sacrifices a collateral digital artery, which may jeopardizean already injured finger. Moreover, the joint may result instiffness. To search for better techniques to reconstruct fingertipor pulp, we did the study in the following.Based on the study of arterial system and innervation oflong fingers, we designed the innervated reverse island flapbased on the dorsal cutaneous branch at the distalinterphalangeal joint of the digital artery to reconstruct sensatefingertip or pulp. The delimitation of donor site lies between proximal creaseof proximal interphalangeal joint and the distal third of themiddle phalanx, with extension from the ulnar to the radialmidlateral line. The end of volar crease of distal interphalangealjoint(DIP) is the pivot point of the vascular pedicle. The axisline, which lies at an angle of about 30 to 45 degrees with themidlateral line, is the body surface projection of the dorsalcutaneous branch at the DIP of the digital artery. The flap isdesigned on the dorsal side of the middle phalanx according tothe size and shape of the fingertip or the pulp defect. The flap is perfused both by the the branch at the level ofthe DIP and numerous small bilateral branches containing in thepedicle, and is drained through the constant communication inthe pedicle between the volar and dorsal vein system. Regional anesthesia can be used, and the tourniquet shouldbe applied on the base of the involved finger. After a skinincision at the proximal margin of the flap is performed, the twosuitable superficial sensory nerve branches distributed to theflap are identified and then cut off at the initial point. Then theflap is raised above the extensor tendon, with care to leave theparatenon intact in order to ensure the survival of thefull-thickness skin graft. Then, a zigzag skin incision throughDIP is carried out. The vascular pedicle is then carefullydissected en bloc with the surrounding 5 mm-widthsubcutaneous tissue, which provides venous drainage.Haemostasis is done completely after release of the tourniquet. The subcutaneous tunnel of the vascular pedicle should be as deep as possible in order to avoid compression of the pedicle. A tension-free epineurorrhaphy with 9-0 nylon suture is carried out between the two sensory nerves of the flap and both cut ends of the digital nerves at the recipient wound. The flap is then unforced sutured to the defect with 0 nylon suture. And the donor defect is covered with a full-thickness skin graft from the flexion side of wrist, using tie-over dressing. The donor site of the skin graft is one-staged sutured. From November of 2003 to August of 2004, we resurfacedthe defects on two fingertips and one pulp with the technique. Allof the defects accompanied the exposure of tendon or bone, andtrauma was the cause. The area of the defects were 1.2cm x1.7cm~2.0cm x 1.8cm. The average size of the defect was 1.6cmx 1.8cm. All the flaps survived completely. After following up 6~9months, the fingers after reconstruction had satisfactoryappearances, soft texture with wear-resisting, without tenderness.No cold intolerance of the involved finger is reported. Static andmoving 2-PD was 4~6 mm and 2~4 mm respectively. Theaverage was 4.6mm and 3.0mm respectively. There were nocomplications in the donated places. The limitations inmovements of interphalangeal joints were less than 10 degrees.No patient complained about resulting scars. This procedure combines an extended glabrous skin with a...