Tegmen Tympani Defect and Temporal Lobe Encephalocele, Secondary to Mastoid Surgery
30 September 2019 (online)
Case Report Tegmen tympani defect and temporal lobe encephalocele, secondary to mastoid surgery.
Introduction Brain herniation into middle ear is very rarely seen in addition to reasons like congenital factors, trauma, and infection. Tegmen defect may develop as a result of iatrogenic events secondary to chronic otitis media surgery with or without cholesteatoma. Since it may cause life-threatening complications, patients must be evaluated and monitored for tegmen defect.
Case Presentation A 47-year-old male patient underwent modified radical mastoidectomy for chronic otitis media with cholesteatoma, by surgeons in West Bengal, followed by a growing mass observed after 2 years postoperatively at the right external auditory canal. CT and MRI showed defect in tegmentum tympani with temporal lobe herniation with CSF. The transmastoid approach was done by otorhinolaryngologist, and cystic lesion in external auditory canal was aspirated and CSF confirmed. Neurosurgeon excised the herniated glial tissue using bipolar cautery. Duroplasty was done, and fibrofatty tissue, bone wax, and temporalis fascia graft were placed. No postoperative complications were noted.
Discussion Bone erosion and dural injury can be observed due to chronic suppuration or as a complication of mastoid surgery in chronic otitis media. It can be due to cholesteatoma or bone erosion with involvement of inflammatory process due to enzymatic destruction. Surgical approaches for meningoencephalocele, due to tegman defect, transmastoid approach, middle fossa approach, and combination of both. In our case, transmastoid approach was chosen by considering the localization and small size of defect. Postoperative complications like, epileptic seizures, CSF leak, transient ischemic attack/stroke, can be expected. However, these complications were not observed in our case.
Conclusion Patients who underwent operation due to chronic otitis media with or without cholesteatoma must be evaluated for tegman defect and brain tissue or dural structures that may be herniated through this defect during and after the surgery. Possible defects must be repaired with appropriate surgery methods and graft materials by considering the localization and the size of the defected area.