What is the primary vascular supply for a pedicled flap from the dorsum of the index finger?

Primary Vascular Supply for a Pedicled Flap from the Dorsum of the Index Finger

The primary vascular supply for a pedicled flap from the dorsum of the index finger is the first dorsal metacarpal artery (FDMA), which provides reliable blood supply through its branches to the dorsal skin of the index finger. 1, 2

Anatomical Basis of the Vascular Supply

• The first dorsal metacarpal artery (FDMA) consistently arises from the radial artery and divides into radial, ulnar, and medial branches that supply the dorsal aspect of the index finger 3
• This vascular bundle is highly reliable, with studies reporting no necrosis in consecutive cases when used for flap transfer 1
• The FDMA forms a consistent anastomosis with the palmar arterial system through perforating branches of the palmar digital arteries, creating a rich vascular network in the dorsal skin of the index finger 3
• The dorsal skin of the index finger also receives blood supply from dorsal perforators that originate from the radial palmar digital artery of the index finger 3

Clinical Applications and Advantages

• The neurovascular pedicle island flap from the dorsum of the index finger includes the FDMA, one or two veins, and terminal branches of the radial nerve, making it a composite flap with both vascular and sensory components 1, 2
• This "kite" flap design allows for a one-stage transfer without requiring a skin pedicle, making it more practical than alternative "flag" flap designs 1
• The quality of venous outflow in this flap is excellent due to the inclusion of dorsal veins, giving it advantages over palmar-based flaps 1
• The flap can be used for reconstruction of the thumb with good circulation and sensation, requiring less postoperative care than many other procedures 2

Technical Considerations

• When harvesting the flap, it's important to include the perforating branches that connect the dorsal and palmar vascular systems 4, 3
• The rotation point of the flap should be distal to the metacarpal head to ensure adequate vascular supply when covering distal defects 5
• There is a higher complication rate in flaps raised from the dorsum of the fingers compared to those from the intermetacarpal space, which should be considered during planning 4
• The rich plexiform network joining the hand skin supply and the dorsal finger skin allows for reliable flap transfer, but surgical dissection should be limited to the level of the middle phalanx to preserve this network 5

Potential Pitfalls and Complications

• Partial necrosis may occur when these flaps are transferred to more distal defects, requiring careful planning of the flap dimensions and pedicle length 4
• When using this flap in a wrap-around technique for both dorsal and palmar aspects, there is an increased risk of partial necrosis due to the greater surface area requiring perfusion 4
• Excessive tension on the pedicle during transfer can compromise the vascular supply, leading to ischemic complications 4
• Careful preservation of the venous outflow is critical to prevent congestion and subsequent flap failure 1, 2