Minina G. Substantiation of the approach to treatment of patients with acoustic neuroma depending on the tumour localization in the internal acoustic meatus.

The thesis is dedicated to substantiation of the approach to treatment of patients with acoustic neuroma (AN) depending on the tumor localization in the internal acoustic meatus. At that, surgical and radiosurgical methods of treatment, as well as observation ("scan and wait") method, were used. The clinical course of the acoustic neurinoma in patients, depending on the tumor site in the internal acoustic meatus was studied. The efficiency evaluation of treatment of the patients with acoustic neuroma depending on the chosen method of treatment: surgical (translabyrinthine and retrosigmoid approaches), radiosurgical, and observation ("scan and wait") methods, was made with due regard to the functional status of acoustic and vestibular analyzers, as well as the facial nerve function before and after the treatment of patients with acoustic neuroma. It was found out that deafness was more certain to occur in the patients whose tumours were localized at the fundus of internal acoustic meatus (27.4%); if the patients' internal acoustic meatus fundus was tumor-free, deafness occurred in 10.4% of the cases (p<0.01). The facial nerve paresis and facial numbness are a more characteristic presentation for the patients with the tumor localized at the fundus of the internal acoustic meatus (IAM) in 27.0% and 43.5% cases, respectively, whereas they were found in patients with tumor-free IAM fundus in 14.5% and 18.7% of the observations (p<0.01). On the data obtained, recommendations as to choice of method of treatment of patients with AN were made. The modified translabyrinthine approach is recommended for the total tumor removal if it is localized at the IAM fundus, and there is evident hearing loss; if AN does not extend to IAM fundus and the patient's hearing is preserved, the retrosigmoid approach should be used. Stereotaсtic radiosurgery (SRS) made it possible to reduce the tumor size in 72%, and stabilize it in 24% of the patients. On the ground of the data obtained, it is recommended to use SRS in case hearing and vestibular functions are preserved and the IAM fundus is tumors-free. The observation method ("scan and wait") is recommended when AN is localized at IAM fundus, hearing and vestibular functions are preserved.