Minimally Invasive Dorsal Cheilectomy of the First Metatarsal: A Cadaveric Study.

Background:: Minimally invasive dorsal cheilectomy (MIDC) for hallus rigidus is gaining in popularity. The optimal position for the stab incision for MIDC is dorsomedial to allow an ergonomic sweeping movement of the burr, potentially putting the dorsomedial cutaneous nerve (DMCN) to the hallux at risk. We aimed to quantify the risk of using this minimally invasive technique with a cadaveric study.

Methods:: A total of 13 fresh-frozen cadaveric specimens amputated below the knee were obtained for this study. After the procedure, the specimens were dissected, and structures were inspected for damage.

Results:: The DMCN to the hallux was cut completely in 2 specimens (15%). All the extensor hallucis longus tendons were intact, although in 1 specimen, the tendon showed some fraying on the underside of the tendon. The average distance of the stab incision from the first metatarsophalangeal (MTP) joint was 17.7 (range, 10-23) mm. The relationship of the DMCN to the stab incision was variable. The average distance of the DMCN to the incision was 3.8 (range, 0-7) mm. The danger zone for damaging the DMCN was at one-third the length of the first metatarsal proximal to the first MTP joint.

Conclusion:: The DMCN has been well studied by several authors and has a variable course. This nerve was damaged in 15% of our specimens following MIDC.

Clinical Relevance:: We believe patients should be made aware of this risk when considering surgery. A carefully made working capsular pocket for the burr and marking this nerve before making the incision if palpable could mitigate this risk.