OBJECTIVE
To evaluate the pre-, intraoperative data and the results of surgical treatment of patients with the internal auditory canal (IAC) pathology.
MATERIAL AND METHODS
Preoperative pure tone audiometry, CT scans of the temporal bones and MRI scans of the cerebellopontine angles (CPA) and brain, intraoperative data, as well as postoperative results were analyzed in 92 patients with IAC pathology, who underwent surgery at the National Medical Research Center of Otorhinolaryngology of FMBA, Russian Federation. All patients were divided into two groups: 1) with true lesions of the IAC structures; 2) with pathology of the temporal bone, involving the IAC from the outside.
RESULTS
Clinical manifestations in both groups were similar, with the leading symptom of hearing loss (97.8%). Dysfunction of the facial nerve before surgery was more often detected in patients from the second group of patients (in 80.7% of cases). Translabyrinthine approach was the most often used to remove the pathological process (n=58, 63%), if necessary, intratemporal reconstruction of the facial nerve at the level of IAC or CPA (n=18, 19.5%) was performed. In the 1st group of patients, significantly better results were obtained in the removal of the pathological process in comparison with the second group (χ2=11 (n=79), df=1, p<0.01): residual tumor was detected in 9% of cases; in the second group, the residual process was noted in 36.9%. The auditory function remained at the same level in 80% of patients operated on through the middle cranial fossa approach from the 1st group; other patients operated on by other surgical approaches were deaf. In the early postoperative period, almost 40% of patients had grade IV-V facial nerve dysfunction, while at the last follow-up, most of the operated patients showed an improvement in their functional status in both groups up to grade I–III (n=63, 68.5%). Perioperative complications occurred in patients with a widespread process in both groups of cases. The leading complication was cerebrospinal fluid leak (n=9, 9.8%), in 7 cases that required surgical correction.
CONCLUSION
Destructive processes of the temporal bone with spread to the IAC are associated with a higher risk of facial dysfunction and deafness at the preoperative stage than with true pathology of the temporal bone. Patients with a short duration of facial muscles paralysis can be successfully rehabilitated during the removal of the pathological process by translabyrinthine approach. True intracanalicular IAC pathology usually manifests by milder symptoms and in some cases can be effectively removed by MCF approach with the preservation of auditory function; wait-and-scan protocol is an alternative in such cases. Large IAC and CPA pathology with compression of the brainstem is an indication for surgical treatment, which, however, is associated with perioperative complications and requires appropriate training of surgical and reanimation teams.
