A Prospective Evaluation of the Prevalence of Persistent Median Artery in Patients with Carpal Tunnel Syndrome.

Background: The median artery is an embryonic structure that typically regresses during gestation. Occasionally, the artery remains and is then termed a persistent median artery (PMA). A PMA can be associated with other anatomic anomalies, and has been known to contribute to carpal tunnel syndrome (CTS). Recent literature has observed an increase in PMA prevalence, speculated to indicate microevolutionary change. We performed a prospective observational study to investigate the current prevalence rate of PMA in patients undergoing carpal tunnel release (CTR). Methods: Institutional review board approval was obtained. From October 2020 to January 2021, patients ≥18 years old undergoing open CTR by 9 orthopaedic hand surgeons were included in analysis. Patients undergoing endoscopic CTR were excluded. Intraoperatively, the carpal tunnel was evaluated for the presence of a PMA, median nerve anomalies, or any other anatomic anomalies. If a patient underwent bilateral CTR during the study, only one side was included in analysis as determined randomly. Results: Three hundred and sixty open CTRs in 327 patients were performed during the study. Twenty-seven PMAs were identified, for an overall prevalence rate of 8.3%. The average age of patients with a PMA was 63.6 years (SD 13.3 years), consisting of 15 men and 12 women. There were no statistical differences in age, gender, or laterality between patients that did and did not have a PMA. Thirty-three patients underwent bilateral CTR during the study, with 3 being found to have a PMA unilaterally, and zero having a PMA bilaterally. Two bifid median nerves (0.6%) were also identified. Conclusion: This study represents the highest prevalence rate of PMA directly observed in CTR patients reported to date (8.3%). A PMA is not a rare finding, and it should be recognized and protected during CTR. Occasionally, a PMA can be the cause of an acute presentation of CTS.