Incidence of occult cerebrospinal fluid fistula during paranasal sinus surgery

Objective: To determine the incidence of occult cerebrospinal fluid fistulas after endoscopic paranasal sinus surgery. Design: Prospective diagnostic test study with a 6-month follow-up in case of cerebrospinal fluid detection. Setting: Tertiary care hospital. Subjects: The study population comprised 69 patients undergoing routine endoscopic paranasal sinus surgery. Patients with an obvious intraoperative or postoperative cerebrospinal fluid fistula were not included. Intervention: Analysis of 112 samples from intraoperative applied tamponades and of 69 serum samples using a nephelometric research assay for beta-trace protein (prostaglandin D synthase). Main Outcome Measures: Incidence of occult cerebrospinal fluid fistula during endoscopic paranasal sinus surgery as indicated with the help of a test for beta-trace protein; at least a 6-month follow-up of patients with an occult cerebrospinal fluid fistula; and relation of occult cerebrospinal fluid fistula with surgical experience of the surgeon. Results: beta-Trace protein was found in ethmoid roof samples from 2 patients, giving an incidence of 2.9% for occult cerebrospinal fluid fistula. Both patients were operated on by very experienced surgeons. Signs of a cerebrospinal fluid fistula were not found at follow-up at least 6 months after surgery. Conclusions: Nephelometric beta-trace protein assay is a highly sensitive method to detect otherwise unobserved cerebrospinal fluid fistulas. The clinical course of the 2 patients with an occult cerebrospinal fluid fistula indicated the possibility of an uneventful follow-up of patients with small fistulas.