Review and algorithmic management of the anatomical variations of the medial sural artery perforator flap.

Abstract

Background: Perforator variations in the calf region can be found during medial sural artery perforator (MSAP) flap harvest. This article reviews the perforator anatomy of the posterior calf and proposes an algorithmic approach to MSAP flap harvest when there are no favorable perforators, based on the author's experience and literature review.

Material and methods: The PubMed database was searched for anatomic and/or clinical studies describing the perforator anatomy of the posterior calf. Clinical studies reporting the use of alternative flaps for cases in which perforator anatomy was unfavorable were also analyzed. We summarized the study's characteristics and identified the main anatomical challenges faced during flap harvest. We present our algorithm to address these situations, illustrated with three cases in which perforator variations were found intraoperatively and/or difficulties were encountered during MSAP flap harvest.

Results: The anatomical studies from the literature review showed a mean of 3.2 ± 0.8 (1-7) perforators in the posterior calf. The presence of MSAPs and lateral sural artery perforators (LSAPs) have been reported to be 97.2 % and 62.5 % respectively. The mean number of MSAPs was 1.8 ± 0.32 while LSAPs were 1.3 ± 0.3, favoring a medial dominance. Perforators from MSA and LSA were found at a similar distance below the popliteal crease and from the mid-calf. Our clinical experience showed that MSAPs found anterior to the incision can still be used and even as a chimeric flap. Posterior tibial artery perforator flaps can also be harvested from the same anterior incision. Direct septal perforators from the MSA represent a newly identified anatomical variation. An algorithmic approach is presented for managing MSAP intra-operative perforator variations.

Conclusion: The proposed approach of MSAP flap harvest can provide a useful guide for the microsurgeon to raise alternative flaps in the posterior calf region. We advocate an anterior approach that also gives access to perforators of the sural artery itself and posterior tibial artery perforators. These back-up flaps provide similar tissue characteristics and potential for head and neck and extremity composite tissue reconstruction.