Eustachian Tube Dysfunction Due to Medial Pterygoid Nerve Impairment After Trigeminal Schwannoma Surgery.

BACKGROUND AND IMPORTANCE: Eustachian tube dysfunction due to medial pterygoid nerve impairment is a rare complication after trigeminal schwannoma surgery. Eustachian tube dysfunction leads to fluid inside the mastoid air cell, which requires differential diagnosis with cerebrospinal fluid leakage. CLINICAL PRESENTATION: We present a 49-year-old male patient of trigeminal schwannoma. The extradural middle fossa rhomboid approach was performed. The mastoid air cell was opened during the drilling of the middle skull base. After surgery, mastoid air cell fluid was observed. The fluid volume did not increase during hospitalization. However, at 3 months after surgery, the mastoid air cell fluid gradually increased. Otolaryngological examination revealed serous otitis media on the surgical side. Furthermore, opening dysfunction of pharyngeal orifice of eustachian tube due to the medial pterygoid nerve impairment after trigeminal schwannoma surgery was suspected. Tympanotomy was performed, after which the mastoid air cell fluid disappeared. CONCLUSION: Eustachian tube dysfunction due to the medial pterygoid nerve impairment is a rare postoperative complication of trigeminal schwannoma. This condition can lead to serous otitis media and increased mastoid air cell fluid.