Relevant Insertion Site Anatomy of the Conventus Distal Radius System.

Abstract

The Conventus Distal Radius System (DRS) is an intramedullary fixation scaffold inserted into the lateral aspect of the distal radius. The purpose of this study was to identify insertion site anatomy to illustrate risks associated with the minimally invasive nature of radial-sided implant application. Ten cadavers were utilized. Using fluoroscopy, the 1.1-mm Kirschner wire and template was introduced per manufacturer's guidelines, access guide assembled, and dissection carried out to the superficial radial nerve (SRN) with preservation of the native location. The access guide marked the insertion location for the side-cut drill. This point was measured in relationship to structures nearby, including the SRN, brachioradialis (BR), lateral antebrachial cutaneous nerve (LABCN), and radial styloid (RS). The large guide contacted the SRN in 4 of 10 cadavers and was volar to it in 6 of 10. When volar, the mean distance was 1.7 mm. The tip of the RS to the large access guide averaged 44.5 mm. The small guide contacted the SRN in 2 of 10, was volar to it in 4 of 10, and between the bifurcation in 4 of 10. When volar, the distance averaged 3.25 mm. When bifurcated, the distance from the small guide to both the dorsal and volar branches was 3.5 mm. The distance from the RS to the small guide averaged 37.8 mm. The LABCN was found in the field of dissection in 4 of 10 cadavers. Several structures are at risk during insertion of the Conventus DRS; thus, knowledge of the relevant anatomy of this minimally invasive approach is crucial to optimize outcomes and patient satisfaction, and to avoid nerve injury.