Fixed reference points in mapping medial sural artery perforator location

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

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.

Expanding the Armamentarium of Donor Sites in Microvascular Head and Neck Reconstruction

The field of microsurgical head and neck reconstruction has witnessed tremendous advancements in recent years. While the historic goals of reconstruction were simply to maximize flap survival, optimizing both aesthetic and functional outcomes has now become the priority. With an increased understanding of perforator anatomy, improved technology in instruments and microscopes, and high flap success rates, the reconstructive microsurgeon can push the envelope in harvesting and designing the ideal flap to aid patients following tumor extirpation. Furthermore, with improvements in cancer treatment leading to improved patient survival and prognosis, it becomes increasingly important to have a broader repertoire of donor sites. The present review aims to provide a review of newly emerging soft tissue flap options in head and neck reconstruction. While certainly a number of bony flap options also exist, the present review will focus on soft tissue flaps that can be harvested reliably from a variety of alternate donor sites. From the upper extremity, the ulnar forearm as well as the lateral arm, and from the lower extremity, the profunda artery perforator, medial sural artery perforator, and superficial circumflex iliac perforator flaps will be discussed, and we will provide details to aid reconstructive microsurgeons in incorporating these alternative flaps into their armamentarium.

The Medial Sural Artery Perforator Flap: A Historical Trek from Ignominious to “Workhorse”

Rather than just another “review,” this is intended to be an “overview” of the entire subject of the medial sural artery perforator (MSAP) flap as has been presented in the reconstructive literature from its inception in 2001 until the present, with any exceptions not purposefully overlooked. Unfortunately, the pertinent anatomy of the MSAP flap is always anomalous like most other perforator flaps, and perhaps even more variable. No schematic exists to facilitate the identification of a dominant musculocutaneous perforator about which to design the flap, so some adjunctive technology may be highly valuable for this task. However, if a relatively thin free flap is desirable for a small or moderate sized defect that requires a long pedicle with larger caliber vessels, the MSAP flap deserves consideration. Indeed, for many, this has replaced the radial forearm flap such as for partial tongue reconstruction. Most consider the donor site deformity, even if only a conspicuous scar on the calf, to be a contraindication. Yet certainly if used as a local flap for the knee, popliteal fossa, or proximal leg, or as a free flap for the ipsilateral lower extremity where a significant recipient site deformity already exists, can anyone really object that this is not a legitimate indication? As with any perforator flap, advantages and disadvantages exist, which must be carefully perused before a decision to use the MSAP flap is made. Perhaps not a “workhorse” flap for general use throughout the body, the MSAP flap in general may often be a valuable alternative.

Functional Outcomes of the Medial Sural Artery Perforator Flap in Oral Cavity Reconstruction

BACKGROUND

The medial sural artery perforator (MSAP) flap is an ideal option for reconstruction of oral cavity defects owing to its thin and pliable nature and favorable donor site. Our study presents an assessment of functional outcomes including speech and swallowing in patients with oral cavity tumors reconstructed with MSAP flaps.

METHODS

Patients undergoing MSAP reconstruction for oral cavity tumors between January 2014 and January 2018 were identified from our prospective head and neck cancer database. Functional outcomes were assessed in conjunction with the Speech and Language Team with a minimum follow-up of 6 months. Function (speech and swallowing) was recorded as a performance status scale set up by the assessing health care professional.

RESULTS

A total of 38 patients underwent reconstruction with the MSAP flap over the study period. The patient cohort included 10 female patients and 28 male patients. The age range was from 30 to 78 years, with a mean age of 56.8 years. Complications included 1 flap loss and 1 donor site wound dehiscence.Most patients (84.2%) had intelligible speech at 6-month follow-up and further improvement at 1 year (92.1%). All patients resumed feeding on postoperative day 4, and only 7.8% (n = 3) of the patients required assistance with feeding at 1-year follow-up.

CONCLUSIONS

The MSAP flap provides adequate small-volume replacement for oral cavity reconstructions. Our results indicate that most patients achieve a full diet with no restrictions by 1 year after reconstruction. Most of our patients demonstrated excellent speech with little or no need for repetition in conversation. Over the past few years, this has become the flap of choice for oral cavity reconstruction in our unit.

Calf Perforator Flaps: A Freestyle Solution for Oral Cavity Reconstruction

BACKGROUND

Reconstruction of oral cavity defects requires a thin, pliable flap for optimal functional results. Traditional flap choices are imperfect: the anterolateral thigh flap is excessively thick, whereas the radial forearm flap has a poor donor site. The authors therefore favor calf perforator flaps such as the medial sural artery perforator flap to provide thin tissue with an acceptable donor site. This two-part study aims to demonstrate their suitability for intraoral reconstruction.

METHODS

In the radiologic part of the study, the authors compared thigh and calf tissue thickness by examining lower limb computed tomographic scans of 100 legs. For their clinical study, they collected data prospectively on 20 cases of oral cavity reconstruction using calf perforator flaps.

RESULTS

The mean thickness of the calf tissue envelope was significantly less than that of the thigh (8.4 mm compared with 17 mm) based on computed tomographic analysis. In the clinical study, a medial sural artery perforator was used in the majority of cases (17 of 20). The mean pedicle length was 10.2 cm and the mean time to raise a flap was 85 minutes. There were no flap losses. One patient was returned to the operating room for management of late hematoma and wound dehiscence.

CONCLUSIONS

Calf perforator flaps provide ideal tissue for intraoral reconstruction and are significantly thinner than anterolateral thigh flaps. In addition to medial sural artery perforator flaps, the authors raised both sural and soleal artery perforator flaps in this series. Opportunistic use of the calf donor site allows the harvest of thin tissue with minimal donor-site morbidity.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, IV.