VCOM Research Day Program Book 2023

Medical Student Research Biomedical

22 Characterization of Peronea Arteria Magna: Considering Morphology Beyond Categories

Liza Gomez; Michael McGehee; Christian Dedi; Jonathan Millard Corresponding author: l.gomez@vt.vcom.edu

Edward Via College of Osteopathic Medicine-Virginia Campus

Peronea arteria magna (PAM) is an anatomical variant characterized by anomalous branching of the popliteal artery resulting in hypoplastic or filiform tibial arteries and a disproportionately high-caliber fibular artery as the primary supply to the foot. Previous reports have indicated the prevalence of PAM to be between 0-5%. Due to recent advances in microvascular techniques, use of the fibula as a free graft (FFF) for the treatment of bony lesions has gained popularity. Many have suggested standardizing preoperative vascular mapping (CTA, MRA, or DSA) before FFF transfers to avoid distal limb ischemia in patients with PAM, while others insist that clinical examination of normal pedal and posterior tibial pulses may be sufficient evidence to proceed with the procedure (in the absence of imaging). Although there are many reports of the prevalence of PAM patterning, there have been very few efforts to introduce quantitative methods to describe the trifurcation vessels of the leg in the context of PAM or explore their relative trajectories with clinical considerations. Typical dissection techniques were used to reveal the vessels of 122 lower extremities on 61 whole-body donors (mean age = 84 years ± 10.49, range 55— 101). In cases of PAM, the vessel was left embedded in surrounding tissues to prevent disturbing its natural

anatomical course. The length of the ipsilateral fibula was taken, as well as the distance from the location of the anterior emergence of PAM past the interosseous membrane (estimated on the lateral fibula) to the distal lateral malleolus. The diameters of the AT, PT, and fibular arteries were collected at the ankle joint, and also at their origins in the superior leg. Of 122 lower extremities, four PAM patterns were discovered (3.28%); of the four, three were further evaluated. The average location of the anterior emergence of PAM in the distal leg was 6.38 cm superior to the inferior most limit of the lateral malleolus. The average diameters of the proximal AT, PT, and fibular arteries were 4.11 mm, 3.58 mm, and 4.34 mm, respectively. The average diameters at the ankle joint were 1.44 mm (only one), 2.49 mm, and 3.36 mm, respectively. The course of PAM anteriorly past the plane of the interosseous membrane was extraordinarily consistent at about one/fifth of the length of the fibular shaft measured from the inferior-most limit of the lateral malleolus (X̄=.183, SD 0.005). In two of the three evaluated PAM limbs, the anterior tibial artery terminated before reaching the talocrural joint. In both cases, the fibular artery replaced the dorsalis pedis artery in its canonical anatomical position

between the extensor hallucis longus and extensor digitorum longus tendons. In one interesting case, the PT artery did not diminish appreciably through the entire course of the leg (proximal diameter = 3.66 mm and distal diameter = 3.64 mm). These findings indicate that appreciable dorsalis pedis and posterior tibial pulses may be present in classic locations within individuals with concurrent PAM, suggesting that clinical examination only may not be sufficient to rule out PAM in FFF candidates. Future directions should include evaluating the distribution of local PAM branches to muscles, bone, and surrounding fascia, and skin.

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