The potentially dangerous zone of the dorsomedial cutaneous nerve in minimally invasive surgery for hallux valgus: a cadaveric study

BACKGROUND: This study aims to describe the distribution of the dorsomedial cutaneous nerve (DMCN) in the middle and proximal parts of the metatarsal from a lateral view. The purpose is to provide guidance to surgeons in protecting the nerve during the 3rd and 4th generation minimally invasive surgery (MIS) for hallux valgus (HV). METHODS: A total of 20 cadaveric feet were dissected to expose the course of the DMCN and sentinel vein. Measurements of the distances between the nerve/vein and the upper border of the metatarsal, as well as the height of the metatarsal, were taken from a lateral view. The distribution area was then described in proportion. RESULTS: At the base of the metatarsal, the DMCN was distributed in the upper 25.7% of the area. When it reached the middle of the metatarsal, the DMCN was distributed in the upper 13.2–47.2% of the area. As for the sentinel vein, it was distributed in the upper 23.5–71.9% and upper 4.1–52.7%, respectively, at these two positions. CONCLUSIONS: The area, which is above the line connecting the upper 1/4 point at the base of the first metatarsal and the 1/2 point at the middle of the first metatarsal, is a dangerous zone for the DMCN. Avoiding the zone is recommended during MIS for HV.