Congenital Dehiscence of the Fallopian Canal in Middle Ear Surgery

Reconstructive microsurgery of the middle ear imbues each of the structures of the crowded medial wall of the tympanum with great importance for the otologic surgeon. The rapidly advancing and bolder surgical techniques utilized in chronic middle ear disease, otosclerosis, and congenital middle ear lesions demand awareness of the frequent variations found in the surgical field. The auditory ossicles,1particularly the stapes,7have been studied with great care, and the physiologic importance of the middle ear structures has been clarified.2Caution on bold approaches to the round and oval windows has been advocated by Lawrence.3That the internal auditory meatus, utricle, and saccule are respectively 2.0, 0.5, and 1.0 mm. from the anterior part of the fenestra ovalis7has been demonstrated by Anson and Bast, but there has been only infrequent mention made of the potential danger to the facial nerve in peristapedial manipulations. The