Management of Anterior Skull Base Defect Depending on Its Size and Location
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.