The standardized exploration of the radial nerve during humeral shaft fixation reduces the incidence of iatrogenic palsy.

BACKGROUND: The purpose of this study is to determine if a standardized protocol for radial nerve handling during humeral shaft repair reduces the incidence of iatrogenic nerve palsy post operatively.
METHODS: Seventy-three patients were identified who underwent acute or reconstructive humeral shaft repair with radial nerve exploration as part of the primary procedure for either humeral shaft fracture or nonunion. All patients exhibited intact radial nerve function pre-operatively. A retrospective chart review and analysis identified patients who developed a secondary radial nerve palsy post-operatively. In each case, the radial nerve was identified and mobilized for protection, regardless of whether the implant necessitated the extensile exposure.
RESULTS: Fractures were classified according to AO/OTA guidelines and included 23 Type 12A, 11 Type 12B, and 3 Type 12C. Eight patients had periprosthetic fractures and 28 fractures could not be classified. All patients in the cohort were fixed with locking plates. Surgery was indicated for 36 patients with humeral nonunions and 37 patients with acute humeral shaft fractures. Of the 73 patients, 2 (2.7%) developed radial nerve palsy following surgery, one from the posterior approach and one from the anterolateral approach. Both patients exhibited complete recovery of radial nerve function by 6-month follow-up. No significant differences (p > 0.05) were found in any demographic or surgical details between those with and without radial nerve injury.
CONCLUSIONS: Nerve exploration identification and protection leads to a low incidence of transient radial nerve palsy compared to the rate reported in the current literature (2.7% compared to 6-24%). Thus, radial nerve exploration and mobilization should be considered when approaching the humeral shaft for acute fracture and nonunion repairs. LEVEL OF EVIDENCE: Level III.