Safe zone of supraclavicular nerve during clavicle fixation and its anatomical variations, a cadaveric study.

BACKGROUND: Supraclavicular nerve injury is usually at risk during clavicular fracture fixation. This study aimed to examine the anatomical features and estimate the precise location of supraclavicular nerve branches related to adjacent structural landmarks and to evaluate the differences between sex and side. To highlight the clinical purposes and surgical relevance, this study attempted to define a surgical safe zone that would probably protect the supraclavicular nerve during clavicle fixation.

METHOD: A total of 64 shoulders obtained from 15 female and 17 male adult cadavers were examined, identifying the branching patterns of the supraclavicular nerve, measuring the clavicle length and the course of the supraclavicular nerve referring to the sternoclavicular (SC) and acromioclavicular (AC) joint. Data were categorized by sex and side, and their differences were evaluated using Student T-Test and Mann-Whitney U Test. Clinically relevant predictable safe zones were also statistically analyzed.

RESULT: The results revealed 7 branching patterns of the supraclavicular nerve. The medial and lateral nerve branches formed a shared trunk, and the medial nerve branches separated to form the intermediate branch, i.e., the most frequent pattern (67.19%). The safe zones were determined to be 6.1 mm among both sexes of the SC joint medially, and 0.7 mm among females and 0 mm among males of the AC joint laterally. Surgical incisions between 29.3 to 51.2% and 60.5 to 79.7% of the clavicle length from the SC joint were the safe zones at the midclavicular shaft among both sexes.

CONCLUSION: The findings of this study have provided new insights into the anatomy of the supraclavicular nerve and its variations. It has been revealed that the terminal branches of the nerve consistently pass over the clavicle in a predictable pattern, emphasizing the importance of considering the supraclavicular nerve's safe zones during clinically relevant surgeries. Nevertheless, due to individual anatomical variations, meticulous dissection between these safe zones is necessary to avoid iatrogenic nerve injury among patients.

LEVEL OF EVIDENCE: Basic Science Study, Anatomic Study.