Middle ear microvascularization: an "in vivo" endoscopic anatomical study.

PURPOSE: To describe the in vivo vascularization of middle ear by an endoscopic point of view, particularly focusing on the medial wall of tympanic cavity and incudostapedial region (ISR).

STUDY DESIGN: Case series with surgical videos review and anatomical description.

METHODS: 48 videos from exclusive endoscopic middle ear surgery performed at the University Hospital of Modena from November 2015 to July 2017 were reviewed. Data about anatomy of vessels, and blood flow direction (BFD) were collected in an appropriate database for further analyses.

RESULTS: 48 cases were included in the present study. In 18/48 patients (37,5%), a clearly identifiable inferior tympanic artery (ITA) was present, running just anteriorly to the round window (RW), with a superior BFD (65% of cases) from the hypotympanic region toward the epitympanum. Some promontorial variants were described in 67% of cases and the most common finding was a mucosal vascular network with a multidirectional BFD. On the ISR, an incudostapedial artery (ISA) was detected in 65% of cases with BFD going from the long process of the incus (LPI) toward the pyramidal eminence in the majority of cases.

CONCLUSION: The vascular anatomy and BFD of the medial wall of the tympanic cavity can be easily studied in transcanal endoscopy. ITA (with a superior BFD in most cases) and ISA (with a main BFD from the incus to the stapes) are the most constant identifiable vessels.