A new landmark for superior semicircular canal: Spine of Henle

Abstract

Objectives: In this study, we aimed to investigate whether the spine of Henle could a new landmark for the localization of the superiorsemicircular canal (SCC).Patients and Methods: Between March 2014 and March 2015, a total of 30 adult cadaveric temporal bones were used in thisstudy. All temporal bones were positioned and, then, canal-wall up mastoidectomy and facial recess approach were performed. Thelandmarks such as sigmoid sinus (SS), middle cranial fossa dura (MCFD), posterior cranial fossa dura (PCFD), SCCs, short processof the incus, facial nerve (FN), and chorda tympani nerve were identified. The shortest distances between the spine of Henle and thefollowing structures were measured: (i) superior SCC; (ii) lateral SCC; (iii) posterior SCC; (iv) MCFD; (v) PCFD; (vi) SS; and (vii) FN.All measurements were performed using a digital caliper.Results: After excluding three temporal bones with absent spine of Henle, 27 temporal bones were studied. The mean distancesbetween the spine of Henle and the superior, lateral and posterior SCCs, MCFD, PCFD, SS, and FN were 20.3±2.4, 15.9±2.1,17.8±2.0, 13.7±2.9, 19.0±2.7, 14.9±3.6, and 15.8±1.7 mm, respectively. The distances between the spine of Henle and superior SCCwere higher in the temporal bones, while the distances between the spine of Henle and MCFD were higher than the mean values.Similar differences were found for the distances between the spine of Henle and the lateral and posterior SCCs and PCFD.Conclusion: Based on our study results, the spine of Henle can be used as a landmark for the localization of the superior SCC duringmastoidectomy and superior SCC surgeries.