Department of Joint Surgery, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China.
Department of Burn and Plastic Surgery, Children's hospital of Chongqing Medical University, Chongqing, China; Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing, China; China International Science and Technology Cooperation base of Child development and Critical Disorders, Chongqing, China; Chongqing Key Laboratory of Pediatrics, Chongqing, China.
J Plast Reconstr Aesthet Surg. 2021 Aug;74(8):1840-1847. doi: 10.1016/j.bjps.2020.11.032. Epub 2020 Dec 13.
The role of the plantar nerve in the pathogenesis of macrodactyly of the foot is unknown. We investigated the distribution of affected toes and forefoot in 27 feet of 26 patients with pedal macrodactyly, and how this relates to innervation of the affected plantar nerve. A preoperative ultrasound examination was performed to determine the diameter and structure of the plantar nerve. Histologic findings were recorded during surgery. The microstructure of affected plantar nerves was evaluated by hematoxylin-eosin staining, while S100 expression was assessed by immunofluorescence analysis. Phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA) gene mutation in the affected nerve tissue was detected by Sanger DNA sequencing. The affected toes and forefoot involved innervation of the medial plantar nerve in 25/27 feet, the lateral plantar nerve in one foot, and both medial and lateral plantar nerves in one foot. All affected plantar nerves, which were accompanied by a fatty strip, were surrounded by or infiltrated with fat. The affected plantar nerves showed enlargement, a tortuous course, fatty infiltration, or a combination of these. Pathologic changes in affected plantar nerves involved only the epineurium and not the perineurium or endoneurium. Expression of the Schwann cell marker S100 was absent in some areas of affected nerves. Sequencing of PIK3CA exons identified a gain-of-function mutation (p.His1047Arg) in affected plantar nerves. These results indicate that pathologic impairment of the plantar nerve can lead to macrodactyly of the foot, which may be considered as a nerve trunk disease.
足底神经在足部巨趾症发病机制中的作用尚不清楚。我们研究了 26 例患者的 27 只足部受累足趾和前足的分布情况，以及这与受累足底神经的神经支配有何关系。术前进行超声检查以确定足底神经的直径和结构。术中记录组织学发现。通过苏木精-伊红染色评估受累足底神经的微观结构，通过免疫荧光分析评估 S100 表达。通过 Sanger DNA 测序检测受累神经组织中磷酸肌醇-4,5-二磷酸 3-激酶催化亚单位 α（PIK3CA）基因突变。受累的 27 只足中，25 只足的受累趾和前足由足底内侧神经支配，1 只足由足底外侧神经支配，1 只足由足底内侧和外侧神经支配。所有受累的足底神经均伴有一条脂肪带，被脂肪包围或浸润。受累的足底神经表现为增粗、迂曲、脂肪浸润或三者兼有。受累足底神经的病理改变仅累及神经外膜，不累及神经内膜或神经束膜。受累神经的施万细胞标志物 S100 在某些区域表达缺失。PIK3CA 外显子的测序确定了受累足底神经中的功能获得性突变（p.His1047Arg）。这些结果表明，足底神经的病理性损害可导致足部巨趾症，可将其视为神经干疾病。
