[Microsurgical treatment of ethmoid-sphenoidal fluid fistula].

Traumatic basal skull fracture and iatrogenic injury during surgery are the main causes of cerebrospinal fluid (CSF) fistulas. The roof of the ethmoid and the cribriform plate are the most frequent sites of CSF rhinorrhea. The technique for repairing CSF leaks has evolved from intracranial repair to extracranial approaches. From March 1995 to June 1996 five patients with CSF rhinorrhea underwent microsurgical transnasal repair. In four cases of ethmoid defects, a pedicled vascularized mucoperiostal flap was obtained from the ipsilateral septum and placed over the defect. The fifth CSF leak came from the sphenoid and was repaired by packing the sinus cavity with abdominal fat. In all cases the CSF pressure was reduced with a lumbar drain for 5-10 days. The nasal packing was removed on the 5th day. All five patients have been followed up regularly for at least 6 months. To date there has been no evidence of recurrence. The surgical microscopic approach has some advantages: it permits good control of the surgical field and bleeding. In addition, stereoscopic vision provides the surgeon with a meticulous apposition between the flap and the CSF leak. The surgical technique is discussed in detail.