Bone dehiscence in the middle ear in patients operated on in the Otolaryngology Department of Jagiellonian University, Poland from 2008 to 2012

Background: We perform the middle ear operation to remove pathological tissue and in the next step present ossicular chain reconstruction. Otosurgeon has to also identify bone dehiscences, as a potential way to develop otogenic intracranial and intratemporal complications. Aim: We analyzed the patients with bone defects in the middle and/or posterior cranial fossa who present also defects of the bony wall of the facial nerve canal and lateral semicircular canal. Material and method s: We observed 537 patients who were operated on middle ear for the first time in the Department of Otolaryngology at the Jagiellonian University of Cracow from 2008 to 2012. We used a special questionnaire that includes diagnostics of the ear's disease, method of the operation and short- and long-term effects. Results: We discuss 45 patients with the skull base defects in the middle and/or posterior cranial fossa. Dehiscence of the bony wall of the facial nerve canal was present in 7 patients. In 4 cases semicircular canal fistula coexisted. The most common cause of bone dehiscence was granulation tissue, less frequently cholesteatoma. Conclusions:1. Apart from skull base defects in the middle and/or posterior cranial fossa, frequency of bony dehiscence of the facial nerve and semicircular canal fistula is the same as in all population operated on ear.2. Defects of the bony wall of the facial nerve and semicircular canal fistula are observed more frequently in granulomatous chronic otitis media than in cholesteatoma chronic otitis media.3. We observe the same frequency of intracranial complication in population of patients with defects of the bony wall of the facial nerve canal and horizontal semicircular canal than in all groups with skull base defects