Treatment of meningoencephalic herniation of the temporal bone using a combined access in a 17-year-old patient – I.G. Andreeva, E.R. Bariev, D.I. Abdullin

Background. Meningoencephalic herniation (MEH) of the temporal bone is quite rare, manifests by herniation of the brain and its membranes through a bone defect in the middle cranial fossa (MCF) and/or posterior cranial fossa and carries a potential threat to the patient’s life and health. Сlinical case. Female patient Kh., 17 years old, presented in August 2021 with complaints of hearing deterioration on the right ear to conductive hearing loss of the 2nd degree. She had a history of radical surgery on the right ear with tympanoplasty type 3 and mastoid process plasty for chronic otitis media in 2017. Hearing was within normal limits post-surgery until 2021. Examination of the right ear revealed that the posterior wall of the mastoid cavity is detached and fluctuating, transparent fluid was obtained during the puncture, and the glucose test was positive. The neotympanic membrane was not visible. CT scan of the temporal bones and MRI of the brain revealed MEH and a defect of the temporal bone of 8,23×9 mm, which was formed due to prolapse of the upper wall of the mastoid process thinned after radical operation. We performed a combined access surgery. The following objectives were set: to excise the MEH, to eliminate the threat of intracranial complications, to close the temporal bone defect, and to improve hearing. Craniotomy of the temporal bone was performed, MEH excised, and the dura mater (DM) was sutured. To additionally seal DM, a Tachocomb plate was placed on the sutures, the bone defect was epidurally closed with cartilage from the auricle and a part of the temporal fascia. The bony overhangs of the mastoid process were drilled out with a drill, and the MEH was removed from the middle ear side. During revision of the ear, no cholesteatoma was found; adhesions in the tympanic cavity were dissected. The neotympanic membrane, reinforced with cartilage, returned to the stapes. Reconstruction of the postoperative middle ear cavity was performed: the attic was closed with cartilage, the temporal bone defect on the mastoid process side was closed with a bone plate, obliterated with bone chips. The temporal fascia covered the reconstructed cavity and was tucked under the neotympanic flap. In the postoperative period, follow-up CT scan showed the stability of the MCF defect plasty. Conclusion. At examination after 3 months, the patient had no complaints. Hearing has improved to a 1st degree conductive hearing loss in the right ear. The neotympanic membrane is intact, and the postoperative cavity is small. According to the results of brain MRI after 3 months, there were no signs of DM prolapse. This case demonstrates the successful solution for a complex combined condition and the multidisciplinary work of specialists: an otorhinolaryngologist and a neurosurgeon. Keywords: meningoencephalic herniation, temporal bone defect repair, tympanoplasty, transmastoid-transcranial approach, multidisciplinary approach, dura mater Conflicts of interest. The authors have no conflicts of interest to declare.