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.