OSTEOPLASTIC FRONTAL SINUSOTOMY AND EXTRADURAL MICROSURGICAL REPAIR OF FRONTOBASAL CEREBROSPINAL-FLUID FISTULAS

The choice of the surgical approach and operative technique for the ma nagement of cerebrospinal fluid (CSF) fistulas of the anterior cranial fossa are still a controversially discussed topic. Although ''extracr anial'' approaches through the paranasal sinuses are becoming increasi ngly more popular among otolaryngologists and maxillo-facial surgeons, most neurosurgeons traditionally prefer the ''intracranial'' repair o f CSF fistulas by a craniotomy. We present an approach through the fro ntal sinus for the repair of dural defects behind the posterior wall o f the frontal sinus and at the floor of the anterior cranial fossa. Th e operative procedure comprises the following main steps: 1) exposure of the anterior wall of the frontal sinus by a bicoronal incision; 2) excision of the anterior wall without frontal bun holes; 3) bilateral removal of the posterior wall of the fronal sinus; 4) extradural inspe ction of the dura behind the frontal sinus and above the cribriform pl ate, ethmoidal roof, and orbital roof bilaterally; 5) closure of dural tears by direct suture and a periosteal graft; 6) reinsertion of the anterior wall of the frontal sinus and fixation with titanium micro pl ates. Twenty-five patients operated upon using this technique are desc ribed. The aetiology of the frontobasal lesion was traumatic in 23, an d an ethmoid carcinoma in two. In all patients, the dural fistulas wer e successfully repaired during the initial procedure. One patient died from sudden circulatory arrest after an uneventful postoperative cour se of nine days. Otherwise, there were no postoperative complications. This technique affords atraumatic extradural inspection and repair of dural fistulas bilaterally behind the frontal sinus, and above the cr ibriform plate and the ethmoidal and orbital roofs with none or minima l brain retraction. It therefore allows early repair of CSF fistulas a lso in patients with severe brain injury. Although we consider the ext radural closure of fistulas the method of choice, this approach also a llows for a combined extradural-intradural procedure, thus enabling th e surgeon to treat associated intradural pathologies, such as traumati c lesions or rumours of the frontal cranial base.