Combined Middle Cranial Fossa Approach with Endoscopic Assisted Skull Base Repair of Pseudomeningocele and Tympanoplasty – A Case Report

Abstract

The tegmen tympani is a bony plate that forms the antrum and the ceiling of the tympanic cavity. It divides middle ear air from the subarachnoidal area that houses brain and cerebrospinal fluid (CSF). This specific region of the temporal bone may be the source of a defect that causes CSF otorrhea, or CSF leakage, and may result in meninges and brain tissue herniation (meningoencephalocele). Infectious infections, traumatic traumas, congenital deformities, iatrogenic causes, cholesteatomas, neoplastic invasion of the skull base, and spontaneous causes can all result in temporal bone CSF leakage. Clinical signs are frequently vague. Patients may have headaches, tinnitus, hearing loss, auditory fullness, and imbalance. Clinical examination may reveal middle ear effusion, otorrhea, rhinorrhea, and pulsatile movement of the tympanic membrane. Diagnosis of CSF otorrhea can be performed by β2- transferrin and β-trace protein analysis in the fluid suspected to be CSF. MRI and CT imaging are the most commonly applied modalities in the evaluation of encephalocele and suspected
CSF otorrhea.1 The surgical approaches of choice for the repair of tegmen tympani defects depend on the location and size of the bony defect, the status of the ossicular chain, and the experience of the surgeon. Most authors consider a transmastoid (TM) repair as the best surgical approach for the treatment of small tegmental defects. In fact, this minimally invasive surgical approach allows repair of the dehiscence without manipulation and elevation of the dura of the middle cranial fossa (MCF). However, when a large tegmen defect is found in
association with CSF leakage, more invasive surgical techniques may be required. In this case we adopt an MCF approach.2