Anatomic Relationships After Instrumentation of the Midshaft Clavicle With 3.5-mm Reconstruction Plating: An Anatomic Study

OBJECTIVES: To examine the anatomic relationships of the major neurovascular structures at the midshaft clavicle region as they pertain to plate osteosynthesis in the treatment of midshaft clavicle fractures. METHODS: Fifteen fresh cadaveric specimens were dissected at the clavicle region. The shortest distances from the midshaft clavicular fracture lines to the subclavian artery and vein and brachial plexus were measured with a digital caliper with the limb in anatomic position and at 90° of abduction. The mean and range distance values were recorded. The clavicles were then instrumented with eight-hole, 3.5-mm reconstruction plates and screws (Synthes, Paoli PA) placed in superior and anteroinferior positions. The shortest distances from the screw tips to the neurovascular structures were measured at variable plate positions, fracture zones, and limb positions. The incidence of screw tip contact was reported. RESULTS: In 20% (three of 15) of the specimens, screw tip contact with a major neurovascular structure occurred. In these three specimens, two screw tip contacts occurred with the plate in a superior position and two occurred with the plate in an anteroinferior position. In one specimen, screw tip contact occurred with both plate positions. Limb abduction to 90° consistently increased the distance of the neurovascular structures from the clavicle. There was no observable trend in screw contact frequency in respect to limb position or fracture zone. CONCLUSION: Caution must be exercised when instrumenting midshaft clavicle fractures regardless of chosen plate position. Limb abduction to 90° provides an added measure of safety during clavicle instrumentation.