Funktion des N.�facialis nach operativer Therapie des Akustikusneurinoms

[Typical tumors of the petrous bone]

In the region of the petrous bone, inner acoustic canal and cerebellopontine angle, a variety of different tissues can be found, such as bony, epithelial, neural and vascular structures. Tumorous or tumor-like lesions, vascular or bony malformations or other pathologies can therefore be found in all of these areas. We discuss various frequently occurring tumorous or tumor-like pathologies including congential lesions, such as mucoceles, inflammatory disorders including osteomyelitis, pseudotumors and Wegener's granulomatosis. Benign non-neoplastic lesions, such as cholesteatoma, cholesterol granuloma, epidermoid and benign neoplastic tumors, such as the most commonly found vestibular schwannoma, meningeoma, paraganglioma, vascular pathologies and finally malignant lesions, such as metastasis, chordoma or chondrosarcoma and endolymphatic sac tumor (ELST) are also discussed. The emphasis of this article is on the appearance of these entities in computed tomography (CT) and more so magnetic resonance imaging (MRI), it provides key facts and typical images and discusses possibilities how to distinguish these pathologies.

Long-term facial nerve function evaluation following surgery for large acoustic neuromas via retrosigmoid transmeatal approach

PURPOSE

By evaluating the postoperative facial nerve function of large acoustic neuromas, the purpose of this study was to analyze the factors that influence the facial nerve function outcome and to explore the surgical strategy for large acoustic neuromas.

METHODS

A retrospective study of surgical outcome was performed on 89 patients with large acoustic neuromas. All operations were performed via the retrosigmoid transmeatal approach using the intraoperative electrophysiological monitoring.

RESULTS

Gross total resection was performed in 38 (42.7%) of the 89 patients, near total resection in 35 (39.3%), and subtotal resection in 16 (18.0%). The facial nerve was anatomically intact at the end of surgery in 83 (93.3%) patients. At 1 year after surgery, 48 (53.9%) patients had good facial nerve function (House-Brackmann (HB) Grades I-II), 23 (25.8%) patients had regular facial nerve function (HB Grades III-IV), and 18 (20.2%) patients had poor facial nerve function (HB Grades V-VI).

CONCLUSIONS

For large acoustic neuromas, the goal of complete tumor resection and preservation of acceptable facial nerve function can be attained via the retrosigmoid transmeatal approach, using the intraoperative facial nerve monitoring. The surgical strategy of near total resection is indicated for the large acoustic neuromas with severe adherence or inclusion in order to preserve facial nerve function.