Microsurgeon.org

An atlas of microsurgery techniques and principles.


Great Toe Neurovascular Island Flap

Great Toe Neurovascular Island (Toe Pulp) Flap

Anatomic considerations

Tissue:
Sensate glabrous skin.
Innervation:
The lateral plantar digital nerve to the great toe.
Blood supply:
First dorsal metatarsal or plantar digital artery.
Artery:
Can be less than 1 millimeter if taken distally, a progressively larger caliber when dissected more proximally.
Vein(s):
The dorsal subcutaneous venous system.

The lateral pulp of the great toe provides a glabrous skin flap suitable for resurfacing fingertip injuries, providing a sensate reconstruction for replacing like with like.  The donor area can often be closed primarily, minimizing recovery time and leaving minimal aesthetic deformity.

Anatomy

The great toe and pulp can have either dorsal or plantar dominant inflow.  Because it is primarily used in fingertip reconstruction, a short short vascular leash is most commonly needed, and the arterial system need not be traced proximally for great length.  The plantar system is typically used to coapt with the volar digital vessels. The venous system is quite small at the proximal edge of the pulp, and great care must be taken not to injure the venous outflow vessel or vessels.  The vein is traced back onto the dorsum of the foot to a dorsal draining vein.

Vascular Anatomy Great Toe Pulp

Vascular inflow and nerve supply to lateral great toe the great toe pulp. The lateral to gets its plantar sensation from the lateral plantar digital nerve. The accompanying artery provides vascular inflow. If greater length is needed on the artery, it can be traced more proximally. For a more detailed discussion of the anatomy to the great toe, see thegreat toe flap.

The lateral digital nerve to the great toe joins the medial nerve of the second toe at the level of the metatarsal head to form a common digital nerve.  If length is needed, an intraneural microdissection of the common digital can be performed to gain greater nerve length for up to 2 centimeters.  The dissection intraneurally cannot be continued when there is crossover communication of fascicles. 

Operative Procedure

The flap is designed with a central axis along the neurovascular bundle and using an elliptical skin paddle.   Because a "pinch" test is difficult on the fixed glabrous skin of the great toe, the surgeon needs to consider that primary closure is difficult with wounds wider than two centimeters.  But the defect can be skin grafted, provided flexor tendon naked of paratenon is not exposed in the dissection.  The proximal incision is made over the bundle between the metatarsal heads, and a dorsal extension is made over the web space to catch the cutaneous dorsal draining vein. Volar veins are not adequately large to drain the flap.

The Design of the Incision

The skin incision is made with an elliptica pattern from near the tip of th toe to the web space. Dorsal and plantar incisions are made from the web to allow visualization of the pedicle and nerve supply. Venous drainage is taken from the dorsal subcutaneous venous system.

We incise over the neurovascular bundle to identify the pedicle and the entry of the artery and nerve into the flap territory. With the neurovascular pedicle identified, the lateral incision can be angled to avoid injury to the artery and nerve. Dorsally, the vein is identified and traced to from the flap proximally over the foot.

The Artery and Nerve Are Identified

The artery and nerve are identified from the plantar and dorsal view.

The lateral incision is made with a wedge of subcutaneous fat, deep to the bundle and pushing the bundle medially. Small branches from the artery can be coagulated with the bipolar cautery as they are encountered.

The Flap is Raised with the Pedicle

The flap is elevated laterally deep to the pedicle and just superficial to the flexor tendon sheath. This level captures the arterial inflow and venous drainage.

The medial wedge can then be cut with a scalpal, again incorporating the pedicle into the flap and coagulating small vessels. The pulp is dissected away from the deep septal attachments. Although the incision takes a deep wedge, the tendon sheath is left intact and the paratenon is not violated.

On the dorsum of the foot, the vein is traced to the length needed in the revipent area. The deep peroneal nerve need not be divided since it does not supply sensation to the pulp. If the arterial length is needed and the supply is dorsal dominant, the artery can be traced dorsally.

The Flap is Isolated

The dorsal venous system is traced proximally.

The Flap is Isolated

The flap is isolated. The draining vein is obtained from the dorsum of the foot.

The incision is closed with simple sutures and the patient is allowed to dangle and weight bear as healing progresses. If too much tension is placed on the wound, the toe can become ischemic, and the wound should then be skin grafted instead of closed primarily.