Middle ear secretions following spontaneous CSF leak repair may represent effusion rather than CSF leak

Objective: To characterize middle ear (ME) effusion still present 2 months after repair surgery for spontaneous cerebrospinal fluid (CSF) leak via the temporal bone (TB).

Study design: A retrospective chart review (2011-2022).

Setting: Tertiary referral academic center.

Subjects and methods: All patients with persistent ME effusion at 2 months after surgery were included in this study. The indication for surgery for spontaneous TB CSF leak was an active CSF leak with tegmen dehiscence. The presence of effusion was established by findings on microscopic otoscopy aided by tympanocentesis.ME with effusion were sampled for the presence of 𝛽2transferrin. Those negative for 𝛽2transferrin had a ventilation tube placed for ME aeration of serous otitis media (SOM). Data on persistent fluid leakage from tympanostomy tubes, presence or absence of 𝛽2transferrin in the ME, and residual air-bone gap on the postoperative audiogram were recorded.

Results: Fifty-three ears underwent surgery to repair a CSF leak, 42 via a middle fossa craniotomy and 11 via transmastoid approaches. Fourteen ears (26%) still had ME effusion 2 months after surgery and it was sampled for 𝛽2transferrin. Seven were negative (SOM or mucoid OM) and the patients received a tympanostomy tube with resultant ME aeration and air-bone gap closure. The other seven underwent revision surgery.

Conclusions: Postoperative ME fluid after surgery for TB CSF leak may often represent effusion by SOM rather than an ongoing or recurrent CSF leak. ME effusion by SOM is likely caused by mucosal irritation from long-standing stagnant CSF or an underlying eustachian tube dysfunction.