Resection of small acoustic neuroma using the transcanal transvestibular\nendoscopic approach
The second patient, a man in his 30s, presented with a 2-month history of right-sided\nhearing loss and right-sided facial paralysis. He had persistent tinnitus, occasional\nvertigo, no ear discharge, and no ear pain. Oral glucocorticoids and neurotrophics were\nadministered for 2 weeks; however, the patient’s symptoms did not improve, and he visited\nour hospital again 1 month later. A physical examination revealed complete eardrums and no\neffusion in the tympanum. The right-sided facial paralysis was House–Brackmann stage III.\nPure-tone audiometry indicated a threshold of 75 dB in the right ear. Preoperative\ngadolinium-enhanced MRI showed a small (12- × 10-mm) right-sided tumor.\nBoth operations were performed using oral tracheal intubation under general anesthesia.\nBoth patients were placed in the supine position with the head tilted to the contralateral\nside. The operative team comprised a chief surgeon, an anesthetist, a circulating nurse, and\na scrub nurse. The surgical site was exposed through the external auditory meatus. A 0º,\n3-mm-diameter endoscope (Karl Storz, Tuttlingen, Germany) was inserted via the external\nauditory meatus. Under endoscopic assistance, a circular incision was made in the skin of\nthe external auditory meatus at its bony–cartilaginous junction. The skin was elevated and\nremoved together with the eardrum to gain access to the tympanic cavity. The external\nauditory meatus bone and scutum were ground with an endoscopic ear drill, and the ossicular\nchain was removed to expose the whole medial wall of the tympanic cavity (including the\nvestibule and the round window) (). The anatomical boundaries of the surgical field were observed; the anterior\nboundary was adjacent to the basal turn of the cochlea, the upper boundary was the tympanic\nsegment of the facial nerve, the lower boundary was the jugular bulb, and the posterior\nboundary was adjacent to the mastoid segment of the facial nerve (). The vestibule was exposed to its depth, and\nthe spherical recess was used as a landmark for the fundus of the internal auditory meatus\nbecause this recess represents the insertion of the inferior vestibular nerve. The\nperivestibular bone was removed to widen the vestibular window, and the promontorium tympani\nwas then carefully ground, opening and exposing the basal turn of the cochlea. The cochlea\nmiddle turn and top turn did not have to be opened, and the scala tympani was preserved.\nOnce the extensions of the incision were complete and the borders of the tumor could be\nclearly seen (), the facial\nnerve and cochlear nerve were located deep in the tumor. They were identified and carefully\nprotected while removing the tumor (). Finally, the tumor was successfully separated from the internal auditory\nmeatus, and all anatomic areas were thoroughly checked for hemostasis. The cavity was closed\nusing a fat pad harvested from the abdomen to occlude the inner ear and middle ear\ndefects.\nBoth tumors were removed completely without residual tumor tissue, and damage to the facial\nnerve was avoided. No patients developed postoperative vertigo, postoperative aggravation of\nfacial paralysis, severe pain, or permanent postoperative complications. All wounds healed\nwithout issue. The patients were followed up for 6 months, and none developed recurrence.\nPostoperative gadolinium-enhanced MRI showed that the tumor was totally removed by the fully\nendoscopic technique ().