The free fibula flap is one of the most versatile flaps with a skin paddle of variable
blood supply. Here, we describe a rare anatomic variant of septocutaneous perforator
and propose an addendum to the existing classification system to accommodate the variations
of our case.
A 49-year-old gentleman with posttraumatic segmental defect of femur was planned for
reconstruction with a vascularized free fibula flap. Intraoperatively, two perforators
were identified, septocutaneous in the distal one-third and musculocutaneous in the
middle one-third of the leg. Due to the long intramuscular course, the musculocutaneous
perforator was ligated initially. After osteotomies, the septocutaneous perforator
was dissected and was found to arise from posterior tibial artery (PTA), coursing
between fibula and flexor hallucis longus (FHL) ([Fig. 1]). The recipient site bony defect was reconstructed using 11-cm free vascularized
fibula flap, fixed with plates, and anastomosed end-to-end with descending branch
of lateral circumflex femoral artery.
Fig. 1 Septocutaneous arising from the posterior tibial artery deep to FHL (blue arrow).
To the best of our knowledge, this is the first report of a septocutaneous perforator
in the distal half of the leg coursing through the posterior septum between the fibula
and FHL and arising from the PTA. These variations require the surgeon to decide on
the salvage options when encountered. In our case, as there was no skin defect, we
decided to raise the flap as an osseous flap. The alternative option would have been
a flowthrough anastomosis in case skin paddle was required.
Yadav et al[1] proposed a classification system of the fibula skin vasculature which was based
on the axial supply of the skin paddle into four types as follows: type A, supplied
by peroneal vessels; type B, by peroneal vessels and posterior tibial vessels (PTV);
type C, by PTV only; and type D, by popliteal artery only. This was further subcategorized
by Parr et al[2] into subtypes A1, A2, A3, or B1, B2, B3, and C1, C2, and C3 based on the type of
perforator (musculocutaneous and septocutaneous), source vessel of the skin paddle,
and their variations and possible salvage measures.
Our case is an uncommon variant of septocutaneous perforator arising from the PTA
coursing between the fibula and FHL ([Fig. 2]). Based on existing classification systems, we were not able to classify any of
them. Hence, we propose a new addition to the Parr classification of type C, subtype
C4 as septocutaneous perforator running between fibula and FHL.
Fig. 2 Posterior tibial artery coursing between the fibula and FHL.
Posterior approach and awareness of all salvage options can help in avoiding a debacle.
