Review Question - QID 219858

The patient has a distal pulp injury with planned soft tissue coverage using a retrograde flow digital artery flap, which requires a patent middle transverse anastomotic arch.

The goals of treatment for distal fingertip injuries include obtaining a sensate and durable distal tip with bone support for nail growth. Most injuries without bone or tendon exposed and with < 2cm of skin loss can be treated successfully with non-operative management and healing by secondary intention with excellent cosmetic result. When soft tissue loss exceeds 2cm and results in exposed bone or tendon where rongeuring bone proximally is not an option, soft tissue coverage options are often considered with flap selection based on location of the tissue defect and the anatomical blood supply to the proposed flap. The retrograde flow digital artery flap is based on the digital artery and is helpful for coverage of pulp defects and dorsal and lateral defects from the distal phalanx to the proximal interphalangeal joint. In terms of hand anatomy, the proper digital arteries arise from the common digital arteries, with the radial and ulnar proper digital arteries continuing within the digits and communicating with each other through three palmar arches, including the proximal, middle, and distal transverse arches. The middle arch is located at the level of the C3 pulley, lying deep to the flexor tendons and providing flow to the digital arteries between the PIP and DIP joints. Given this flow pattern, thus, patency of the digital arteries and middle transverse anastomotic arch are required for flow in retrograde digital artery flaps.

Tan et al. describe the vascular anatomy of the hand in relation to flaps. The authors note that the perforators from the radial, ulnar, and interosseous arteries form the basis of fasciocutaneous flaps from the forearm that are commonly used in the reconstruction of the hand. They conclude that an understanding of the blood supply, branches, and perforators to the skin at different levels is important for reconstructive surgery of the hand.

Panattoni et al. provide surgical tips for avoiding complications in the reconstruction of fingertip injuries. The authors note that when replantation of a fingertip amputation is not possible, flap reconstruction may be necessary for a functional and aesthetically pleasing outcome. They conclude that the most important factor to prevent failure is to have the proper indications, emphasizing a thorough discussion with the patient regarding complications, postoperative management/therapy, and realistic expectations to yield better patient satisfaction.

Seah et al. reviewed retrograde flow digital artery flaps. The authors note that retrograde flow digital artery flaps are a versatile single-stage option for the coverage of fingertip and dorsal digital defects. Techniques vary according to the type of tissue incorporated (adipofascial or cutaneous) and the inclusion of the digital nerve or its branches in the pedicle. They conclude by noting that complications include venous congestion, flexion contracture, and cold intolerance.

Figures A and B are clinical photographs demonstrating a soft tissue deficit of the volar ring finger between the PIP and DIP joints. Illustrations A, B, and C represent pre-op, post-op, and final clinical outcomes of a retrograde digital artery flap courtesy of Seah et al, as cited.

Incorrect Answers:
Answer 1: An axial flag flap is based on the dorsal metacarpal arteries of the hand and is typically used as a simple cutaneous rotational flap from the dorsum of the proximal phalanx that is rotated to cover proximal phalanx or metacarpophalangeal joint defects, not distal pulp defects.
Answer 2: A pedicled groin flap is based on the superficial circumflex iliac artery and is used to cover large dorsal hand soft tissue defects.
Answer 3: The posterior interosseous fasciocutaneous flap, as the name indicates, is based on a posterior interosseous artery pedicle and is used to cover first webspace defects.
Answer 4: A reverse cross-finger flap is a subcutaneous adipofascial flap that relies on dorsal cutaneous branches from the proper palmar digital artery to be successful, and is most often used to cover dorsal defects of the proximal and middle phalanges, not the distal pulp.