Comprehensive algorithm for skull base dural lesion and cerebrospinal fluid fistula diagnosis

Objectives/Hypothesis: Skull base dural lesions and cerebrospinal fluid (CSF) fistulas are potentially vital conditions whose diagnosis can be challenging. The authors' aim was to compose a comprehensive algorithm that combines the most modern diagnostic tools in easily applicable patterns to indicate a possible dural lesion or CSF fistula. Study Design: Prospective clinical study. Methods: The authors collected the data of all patients with suspicion of CSF fistula or dural lesion, or both, between January 1999 and December 2002. Beta-trace protein, beta(2)-transferrin, and endoscopic and laboratory sodium fluorescein tests; high-resolution computed tomography; and magnetic resonance cisternography were used according to the symptoms and etiological factors. The results of the diagnostic tools that were used and intraoperative findings (in case of an operative treatment) were reviewed. Results: From 1999 to 2002,236 patients were evaluated because of suspicion of dural lesion or CSF fistula, mostly after head trauma. Pattern I of the algorithm was applied for head trauma in dural lesion or CSF leak assessment, pattern II for postoperative CSF leaks, pattern III for evaluation of spontaneous CSF rhinorrhea, and pattern IV for the assessment of recurrent pneumococcal meningitis related to dural lesions without CSF fistula. By applying the patterns of this algorithm, a dural lesion or CSF leak that was also confirmed intraoperatively was detected in 48 patients. Conclusion: The four patterns of the new diagnostic algorithm described in the present study enable physicians to reliably clarify suspicions of dural lesions and CSF fistulas and aim to help them choose the best possible management. Each pattern uses the optimal combination of CSF tests and radiological imaging to reach a synergistic effect for precisely detecting dural lesions or CSF fistulas. Accordingly, this improves surgical decision-making when necessary.