Prevalence, Surgical Anatomy, and Clinical Significance of the Thyroidea Ima Artery in Thyroidectomy: A Systematic Review

The thyroidea ima artery (TIA) is an unpaired anatomical variant of the thyroid arterial supply that ascends along the anterior surface of the trachea to the inferior pole of the thyroid gland or the isthmus. Despite long-standing anatomical interest in this vessel, a comprehensive and up-to-date synthesis of the evidence on its prevalence, surgical anatomy, and clinical implications in thyroidectomy is still lacking. This systematic review was conducted in accordance with the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) 2020 guidelines. A comprehensive search of PubMed/MEDLINE (Medical Literature Analysis and Retrieval System Online) was performed, covering the period from January 2010 to December 2025. Out of 54 identified records, 20 met the inclusion criteria and were included in the analysis, comprising 14 case reports, four observational studies based on computed tomography angiography (CTA), and two cadaveric or mixed cadaveric-imaging series, originating from 10 countries. Across the included studies, the reported prevalence of TIA ranged from 0.1% to 5.71%, with cadaveric studies consistently showing a higher detection rate than imaging-based studies. The brachiocephalic trunk was the most frequently reported arterial origin overall, although the aortic arch predominated in certain Caucasian populations, indicating notable population variability. Co-existence of the TIA with unilateral or bilateral inferior thyroid artery deficiency was a recurrent observation, with direct implications for the risk of inadvertent parathyroid devascularization and postoperative hypoparathyroidism. The relationship between the TIA and the recurrent laryngeal nerve remains poorly characterized, although close parallel courses have been described and warrant particular surgical attention. The risk of hemorrhagic complications from unrecognized TIA injury during thyroid, tracheal, or mediastinal surgery is significant, given the vessel's origin from high-pressure great arteries; transcatheter arterial embolization may serve as a safe adjunct for hemorrhage prevention and selective thyroid devascularization in specific clinical scenarios. This review highlights the considerable anatomical variability of the TIA and supports a systematic preoperative vascular assessment, including CTA with three-dimensional reconstruction when feasible, particularly in patients with substernal goiter, known inferior thyroid artery deficiency, or aortic arch anomalies, prior to thyroid or anterior neck surgery.