Surgical anatomy of the singular nerve*

Abstract

1991) Clin. Otolaryngol. 16, 305-308 Surgical anatomy of the singular nerveThe course of the posterior ampullary (singular) nerve has been studied in 30 preserved human temporal bones. In 17 dissections (57%), the nerve was readily accessible in the floor of the round window niche without undue risk to the round window membrane or the ampulla of the posterior semicircular canal. In 5 bones (l6%), the nerve was closely related to the round window membrane and could not have been approached without significant risk of damage to the membrane. In 8 (27%0), the nerve ran more or less directly medially to the internal auditory meatus without entering the round window niche. The ampulla of the posterior semicircular canal would therefore have been at risk if the nerve were approached surgically.

Surgical Therapy in Intractable Benign Paroxysmal Positional Vertigo

“…Many authors emphasized the great difficulty of singular neurectomy by analyzing the anatomy of the singular nerve. Ohmichi et al, 10 Mills et al, 9 and Leuwer and Westhofen 13 called into question the excellent results obtained by Gacek and concluded that in 14% to more than 30% of cases (corresponding to all type 3 nerve and some type 2) singular nerve cannot be found without opening the basal turn of cochlea, making Gacek's good results very difficult to explain (Gacek performs ampullary nerve transsection without identifying the nerve's type preoperatively, and therefore he cannot exclude type 2 and 3 nerve). Leuwer and Westhofen 13 hypothesized that its good results might depend on other mechanisms, maybe vibrations due to drilling.…”

“…In the last 30 years, 342 singular neurectomies have been performed, 252 by Gacek himself. 8 Anatomy of the Posterior Ampullary Nerve [9][10][11][12][13] The posterior ampullary nerve runs from the posterior ampulla to the saccular nerve (forming the inferior vestibular nerve) through the singular canal of Morgagni in temporal bone. It is in the shape of an inverted "J" and is divided into three segments: canalicular (joining the internal auditory canal: straight line of the "J"), intermediate (curve of the "J"), and cribiform (entering the ampulla).…”