Keywords
vessel - dissection - perivascular fibrosis - free flap - microsurgery - dabetic foot
- reconstruction
Foot ulcers are a common and serious complication of diabetes. If not appropriately
treated, these could lead to amputation of the lower limb. After debridement, the
ensuing raw areas may need soft-tissue cover to salvage the foot.[1]
[2] Microsurgical free flaps are increasingly used to solve the problem.[3]
[4] An often-experienced problem is the dissection of sufficient length of recipient
vessels due to perivascular fibrosis. Repeated episodes of inflammation and cellulitis,
which occur due to infection of the ulcer, lead to accumulation of edema fluid rich
in proteins, which, when settled, causes fibrosis.[5] The easily separatable perivascular planes are obliterated, and the fibrotic tissue
surrounds both the artery and the venae comitantes as a whole, appearing like a cocoon.
Attempts to dissect the plane between the artery and the vein could result in injury
to the vessels. Another problem is the difficulty in achieving control of the small
branches of the arteries and interconnecting vessels between the venae comitantes.
This fibrosis can cause vessel narrowing and stiffening, impairing blood flow to the
affected area and decreasing the success rate of the free flap reconstruction procedure.
At our institute, from November 2020 to May 2023, 72 free flap reconstructions of
the diabetic foot were done with a flap success rate of 95.8%. Preparing the recipient
site vessels form the most complex and crucial part of these procedures. The first
step in preparing the recipient vessels is separating an adequate length of the arteries
and veins. Compared to posttraumatic free flap reconstruction of the foot, reconstructing
the diabetic foot poses a unique challenge in recipient site vessel preparation due
to perivascular fibrosis. Instead of attempting to separate the vein and the artery
by dissecting in the plane between them, we prefer dissecting the plane over the artery.
Fine sharp-tipped scissors are used for the dissection. A snip is made in the fibrous
cocoon over the artery with the scissors. Through a series of sharp and blunt dissection,
the plane between the fibrous cocoon and the adventitia of the artery is exposed.
Now the artery becomes distinct from the layers of the fibrous cocoon. Once this plane
is reached, it is extended along the longitudinal axis of the artery, and the fibrous
layer over the artery is cut depending on the length of the vessel required. The superficial
plane is chosen as there are few or no branches that emerge in this superficial plane.
Now the dissection is carried out on either side of the artery. The branches emerging
from the arteries are clearly visualized as the artery is released from fibrosis,
making it easy for the branches to be coagulated or clipped. This allows the artery
to be easily separated from the fibrous cocoon. After an adequate length of the artery
is separated, attention is directed toward isolating the venae comitantes from any
other vessels. Moreover, the venae comitantes also simultaneously separate from the
artery during the course of dissection, thus making it easy for the surgeons to dissect
the veins ([Fig. 1]; [Video 1], available in online version only). The surgeon must be gentle and persistent, making
slow progress in dissecting the fibrosed vessels. Also, we isolate and keep the subcutaneous
veins we encounter, the saphenous vein, and its tributaries as a backup in case the
venae comitantes are severely fibrosed and difficult to dissect or adequately dilatable
with heparin saline.
Fig. 1 (a) Artistic illustration of vessels encased in a fibrotic cocoon. (b) Dotted lines over the artery indicating the line of dissection. (c) The fibrotic cocoon is dissected till the adventitia of the artery is exposed. (d) The dissection proceeds on either side of the artery. (e) The dissection further proceeds to the deeper plane around the artery. (f) The artery is entirely freed from the fibrotic cocoon. The venae comitantes are
separated through dissection of the fibrotic tissue in between them. (g) The artery and the venae comitantes are separated safely from the fibrotic cocoon.
Video 1 Video demonstrating the technique used by the authors in recipient vessel dissection
in diabetic foot patients with perivascular fibrosis.
We attempted free flap reconstruction in 73 patients with diabetic foot ulcers. One
patient had a single-vessel limb with severe fibrosis, and the authors could not dissect
the vessels. The procedure had to be abandoned. In the rest of the 72 cases, this
technique was successful. This technique can also be used in other situations where
fibrosis and dissection of vessels are fraught with danger.
