The Laryngoscope Lippincott Williams & Wilkins, Inc. © 2005 The American Laryngological, Rhinological and Otological Society, Inc.

The Management of Leaks in Patients at Risk for High-Pressure Hydrocephalus

Ricardo L. Carrau, MD; Carl H. Snyderman, MD; Amin B. Kassam, MD

Objectives/Hypothesis: The transnasal endoscopic underwent ventriculoperitoneal shunting after re- approach has become the preferred technique for the pair of the CSF Leak. No recurrence has been ob- surgical management of patients with cerebrospinal served at a follow-up ranging from 24 to 84 months fluid (CSF) leaks of the anterior, sellar, and parasellar (median period, 30 mo). Conclusion: Patients with base. The literature has reported an 85% to 100% high-pressure hydrocephalus may be identified in a success rate for the endoscopic repair of CSF leaks, prospective fashion to prevent recurrence or persis- which compares favorably with that reported after tence of the CSF leaks. The presence or absence of transcranial repair. Despite an adequate repair, a high-pressure CSF may be established by means of subpopulation of patients remain at high risk for re- direct CSF pressure measurement through lumbar currence of the CSF leak attributable to undiagnosed puncture postoperatively. This allows early interven- high-pressure hydrocephalus. Patients at high risk tion and prevention of recurrence. Key Words: Cere- for high-pressure hydrocephalus include those who brospinal fluid, endoscopic sinus , paranasal have had a as a result of sinuses, hydrocephalus. trauma (accidental or surgical) or and those Laryngoscope, 115:205–212, 2005 with spontaneous CSF leaks. Study Design: With the goal of reducing the risk of recurrence, the authors INTRODUCTION developed a protocol for the identification and man- A cerebrospinal fluid (CSF) leak and consequent rhi- agement of patients with CSF leaks who are at risk for high-pressure hydrocephalus. Methods: The protocol norrhea implies a communication between the subarach- includes endoscopic repair, temporary CSF diver- noid space and the sinonasal tract. Patients with CSF sion, measurement of CSF pressure after the repair, leaks present with a variety of symptoms such as clear and immediate ventriculoperitoneal shunting if nec- nasal discharge and or complications such as essary. Results: During the period of September 1999 pneumocephalus, , or abscess. Prompt to April 2002, the authors repaired 25 CSF leaks identification and closure of the CSF fistula is critical through an endonasal endoscopic approach. Nine- to avoid development of or progression to these life- teen patients were considered at high risk for high- threatening complications.1,2 pressure hydrocephalus. Using the protocol de- Most CSF leaks are caused by traumatic fractures of scribed, the authors identified six patients (31%) with the cranial base or by iatrogenic injuries secondary to CSF leaks that could be associated with undiagnosed high-pressure hydrocephalus. All CSF leaks were suc- endoscopic sinus surgery and/or cranial base surgery. Ce- cessfully repaired using a transnasal endoscopic re- rebrospinal fluid leaks are diagnosed in 3% of patients pair. Six patients with high-pressure hydrocephalus with closed head injuries and in as many as 30% of pa- tients with a fracture of the skull base.3 Similarly, iatro- genic trauma, such as traditional cranial base surgery and Presented as a Candidate’s Thesis to the Triological Society, Inc. endoscopic sinus surgery, is associated with CSF leaks. From the Departments of Otolaryngology and , Uni- versity of Pittsburgh School of Medicine, and the Center for Cranial Base Although less than 1% of patients who undergo endoscopic Surgery, University of Pittsburgh Medical Center, Pittsburgh, Pennsylva- sinus surgery develop a CSF fistula, endoscopic sinus nia, U.S.A. surgery is one of the most common causes of CSF leaks in Editor’s Note: This Manuscript was accepted for publication August 4–22 3, 2004. our practice and other practices. Nontraumatic CSF Send Correspondence to Ricardo L. Carrau, MD, University of Pitts- leaks may also occur secondary to tumors of the skull base burgh School of Medicine, 200 Lothrop Street, Suite 500, Pittsburgh, or high-pressure hydrocephalus (HPH), or both. The Pennsylvania 15213, U.S.A. E-mail: [email protected] causes or origins of HPH include tumors, trauma, infec- DOI: 10.1097/01.mlg.0000154719.62668.70 tions, and hemorrhagic cerebrovascular accidents. Occa-

Laryngoscope 115: February 2005 Carrau et al.: Cerebrospinal Fluid Leaks 205 sionally, no cause or origin is identified for the HPH; scope.24–29 Under the Wood lamp (i.e., black light), fluo- therefore, it is deemed “idiopathic.” rescein appears as bright yellow-green; nonetheless, the yellowish color of fluorescein may be identified without Diagnosis the need for special lighting. The diagnosis and management of a CSF leak in- Despite its extensive use in Europe, intrathecal flu- volves three critical steps: distinguishing a CSF leak from orescein is not universally accepted in the United States other sources of rhinorrhea, locating the fistula, and rul- as a diagnostic tool. This is partly attributable to the ing out high secondary to altered logistics of performing a in an outpatient CSF dynamics. A clinical diagnosis of a CSF leak is based setting and to medicolegal considerations (the fluorescein on a history of clear, watery nasal drainage, usually uni- drug package insert includes an advisory warning against lateral, commonly associated with headache. A history of intrathecal use). In addition, intrathecal injections are tumor, trauma, or previous surgery involving the parana- rarely critical to the proper identification of the CSF fis- sal sinuses or cranial base heightens the level of suspicion. tula. Exceptional patients are those with multiple fistulas Increased rhinorrhea when the patient leans over, tilts and patients who have had repeated episodes of meningi- the head forward, or performs a Valsalva maneuver fur- tis in the absence of an apparent cranial base defect or ther suggests the presence of a CSF leak. Occasionally, a other predisposing factors such as rhinosinusitis or otitis patient presents not with rhinorrhea, but with mental media. changes or other neurological deficits caused by a life- Other authors have advocated the intrathecal injec- threatening arising from the CSF leak, such tion of air, which can “bubble” out at the fistula site, thus as pneumocephalus, , or ascending bacterial aiding in its identification.29 However, air is an irritant to meningitis. the brain and may induce . Normal saline solution may be injected into the intrathecal space to increase the Laboratory Tests pressure within the subarachnoid space and thus aid in It should be remembered that other conditions such the identification of the leak. as vasomotor rhinitis and sympathetic denervation can Scintigraphy has been advocated for the identifica- cause profuse rhinorrhea that may be confused with a tion of a CSF leak. Indium (In 111) is the most frequently CSF leak. Nasal irrigation with saline solution during used radioisotope. Although radioisotope tracing is a sen- endoscopic sinus surgery may accumulate in the parana- sitive test, it is associated with a high false-positive rate.24 sal sinuses and later present as postoperative rhinorrhea. In addition, radionuclide studies have a poor resolution Thus, biochemical testing is indicated to confirm the true that precludes establishing the specific point of leakage. nature of the nasal drainage. Cerebrospinal fluid will be Thus, we do not advocate scintigraphy. The presence of high in glucose and low in protein. However, normal nasal the CSF leak is ascertained with a noninvasive test, ␤-2 discharge has been shown to be falsely positive for glucose transferrin electrophoresis, and its site of origin is better in 45% to 75% of cases.23 Beta-2 transferrin is a protein identified by other types of imaging or endoscopy, or both. found in CSF, aqueous humor, and perilymph but not in An important consideration in a patient presenting blood or nasal secretions. Detection of ␤-2 transferrin, with spontaneous rhinorrhea or rhinorrhea after skull based on standard, reproducible principles of protein elec- base trauma is to distinguish whether the CSF rhinorrhea trophoresis and immunofixation, is a noninvasive, reliable arises from the sinonasal tract or from other sites, such as chemical marker of CSF leakage.24–28 the middle ear or mastoid. A CSF fistula within the tem- poral bone may drain into the nose through the eustachian Identifying Site of Lesion tube, leading to an incorrect diagnosis. Imaging is of ut- When a CSF leak develops after sinus surgery, the most importance to locate the site of the fistula. endoscopic surgeon typically has an impression as to the Radiographically, a high-resolution computed tomog- possible site of injury to the cranial base (i.e., site of the raphy (HRCT) scan performed in axial and coronal planes CSF fistula). Therefore, a thorough endoscopic office ex- using 3-mm fine cuts can be used to identify a cranial base amination of the nasal cavity may reveal the site of the defect. High-resolution computed tomography is our pre- leakage. However, the fistula is difficult to identify in ferred initial imaging study to aid in the identification of patients with low-pressure leaks, especially in the pres- the site of injury and its extent. High-resolution computed ence of postoperative tissue edema and blood clots. tomography with contrast also provides information about Intrathecal injection of contrast materials and radio- the possibility of intracranial complications such as hema- active tracers has been used to confirm a CSF leak and to toma or brain contusion that occur in the setting of acute identify the site of origin. Intrathecal fluorescein may be trauma (iatrogenic or other). High-resolution computed used to aid in the diagnosis and localization of the CSF tomography with views taken at a perpendicular plane leak. During this test, 5 mL fluorescein at a concentration from the suspected site of injury can better evaluate the not greater than 5% is diluted with 10 mL CSF (obtained integrity of the bony wall in question. Therefore, coronal through a lumbar puncture) and is then injected intrathe- computed tomography (CT) views are best to evaluate cally. Fluorescein is neurotoxic, and a low concentration– defects of the cribriform plate, fovea ethmoidalis, or pla- low volume injection is critical to avoid the neurological num sphenoidale, whereas axial views are superior to complications associated with higher concentrations. Af- evaluate the posterior wall of the frontal or sphenoid si- ter intrathecal injection of the fluorescein solution, the nuses. Magnetic resonance imaging (MRI) is recom- CSF leak may be visualized using the nasal endo- mended to assess the contents of a herniation of the me-

Laryngoscope 115: February 2005 Carrau et al.: Cerebrospinal Fluid Leaks 206 ninges and/or through the cranial base defect (i.e., meningocele or ). We have en- countered an anterior cerebral artery within a meningo- encephalocele herniated into the nasal cavity. Even HRCT may not identify small areas of surgical trauma or linear nondisplaced fractures. In this case, HRCT can be used in conjunction with intrathecal contrast to identify the fis- tula. Metrizamide CT cisternography has been docu- mented to be both sensitive and reliable. Newer, less toxic, water-soluble nonionic contrast materials have replaced metrizamide and result in fewer side effects (i.e., head- ache, , and arachnoiditis). However, contrast stud- ies require the presence of an active fistula. Intermittent leaks that are temporarily sealed by swelling, inflamma- tion, or brain herniation may yield a false- negative result. A saline challenge test, which involves the intrathecal injection of saline solution to increase the CSF pressure, enhances the sensitivity of the test to diagnose the pres- ence of a fistula. Magnetic resonance imaging cisternography may complement the information offered by HRCT without the use of intrathecal contrast. Magnetic resonance imaging cisternography has been effective in identifying CSF leaks in patients with normal findings on HRCT.30 However, we have had mixed results with the use of this technique. Fig. 1. Patients at risk for high-pressure hydrocephalus were treated according to the protocol shown. CSF ϭ cerebrospinal fluid; Historical Background Hx ϭ history; CT ϭ computed tomography; postop ϭ postopera- In a comprehensive review of 53 CSF leaks that were tively; VP ϭ ventriculoperitoneal. repaired through an endonasal endoscopic approach, we reported three patients in whom CSF leaks persisted or recurred, requiring additional surgery.31 These three pa- tients were subsequently diagnosed with HPH. In each normal, the patient was discharged home and followed in our case, the CSF leak was repaired endoscopically. Patients outpatient offices. As an alternative, patients with CSF leaks isolated to the with elevated CSF pressure underwent ventriculoperito- sphenoid sinus were treated with obliteration of the sinus using neal (VP) shunting. Subsequent to the present report, we abdominal fat followed by stabilization with a nasal packing. A initiated a protocol to prospectively identify and treat postoperative lumbar spinal drain was not inserted. A lumbar patients with CSF leaks who are at risk for HPH and puncture was performed 3 to 5 days after surgery to measure the therefore at risk for recurrence of the CSF leak. opening pressure. As previously mentioned, the need for a VP was established if the CSF opening pressure was elevated. A CT scan of the brain was performed 6 weeks after the PATIENTS AND METHODS surgical closure in patients with normal CSF opening pressure. All patients presenting to the Center for Cranial Base Sur- of the temporal horns and trans-ependymal gery, University of Pittsburgh Medical Center with CSF fistulas edema would identify patients with HPH who may have escaped between September 1999 and April 2002 were included in the identification (false-negative test results). Cerebrospinal fluid ␤ study. All CSF leaks were verified with -2 transferrin. The site leaks in patients who did not present with any of the previously of the leak was identified using a combination of tests including mentioned high-risk factors were repaired endoscopically, and a nasal endoscopy, HRCT scan, and MRI or CT cisternography. All spinal drain was not used. patients underwent an endonasal endoscopic repair. Patients with recurrent CSF leaks, a history of head and/or cranial base trauma, or a history of cranial base surgery and RESULTS those with “spontaneous” CSF leaks were considered at high risk In all, 25 patients were treated during the period of for HPH. Patients at risk for HPH were treated according to the the present study (Table I). The study group was com- following protocol (Fig. 1). posed of 14 female and 11 male patients with a median age The CSF leak was repaired through an endonasal endo- of 41 years (age range, 8–66 y). Various causes or origins scopic approach following sound surgical principles including ad- were identified for the CSF leak, including “trauma” (n ϭ equate exposure, hemostasis, preparation of the fistula, and sta- 4), endoscopic surgery (n ϭ 5), anterior cranial base sur- ble grafting. A lumbar spinal drain was placed intraoperatively or gery (n ϭ 3), sellar surgery (n ϭ 4), or “spontaneous” origin immediately after the surgery. Three to five days after surgery, ϭ the lumbar spinal drain was clamped. If no CSF leak was iden- (n 9). tified for 24 hours, the lumbar drain was removed. Twenty-four Nineteen patients, including those who developed a hours later, a lumbar puncture was performed to measure the CSF leak following trauma or trans-sellar or cranial base CSF opening pressure. If the CSF opening pressure was elevated, surgery and those with “spontaneous” leaks, were deemed a VP shunt was recommended; if the CSF opening pressure was at high risk for HPH. Five of nine patients (55%) with

Laryngoscope 115: February 2005 Carrau et al.: Cerebrospinal Fluid Leaks 207 TABLE I. Patients Data.

Patient Age (y)/Gender Etiology Site of Fistula Hydrocephalus VP Shunt Follow-Up (mo) 1 58/M Surgery Sphenoid No No 32 2 19/M Surgery Sphenoid No No 24 3 36/M Surgery Cribiform No No 53 4 61/F Spontaneous ESR Yes Yes 35 5 12/M Trauma ESR No No 43 6 27/M Trauma ESR No No 46 7 9/F Surgery Sphenoid No No 50 8 50/F Surgery Cribiform No No 39 9 65/M Spontaneous Cribiform Yes Yes 30 10 46/F Spontaneous Sphenoid Yes Yes 31 11 59/F Spontaneous Cribiform No No 27 12 62/M Surgery Cribiform No No 31 13 40/F Spontaneous Cribiform No No 25 14 56/F Spontaneous Cribiform No No 26 15 45/F Spontaneous Cribiform No No 49 16 23/F Surgery Sphenoid No No 31 17 48/F Surgery Sphenoid Yes Yes 24 18 29/M Surgery Sphenoid No No 27 19 54/F Spontaneous Cribiform Yes Yes 32 20 42/M Surgery ESR No No 25 21 15/M Spontaneous Cribiform Yes Yes 25 22 31/F Trauma ESR No No 29 23 66/M Surgery Cribiform No No 37 24 51/F Surgery ESR No No 84 25 56/F Trauma ESR No No 25

VP ϭ ventriculoperitoneal; M ϭ male; F ϭ female; ESR ϭ ethmoid sinus root.

“spontaneous” leaks were found to have HPH. One of four first endonasal repair of CSF rhinorrhea using a septal patients (25%) with a CSF leak after cranial base surgery flap. Subsequently, Montgomery33 described his experi- showed evidence of HPH. None of the three patients with ence with septal flaps through an external nasal approach CSF leaks associated with a history of a closed or pene- to treat CSF rhinorrhea. In 1976, McCabe34 reported his trating showed HPH. Likewise, none of three experience with the use of osteomucoperiosteal flaps from patients with CSF leaks presenting after surgery for pi- the septum or middle turbinate through an external eth- tuitary tumors was found to have HPH (one of the four moidectomy approach. In 1989, a report by Yessenow and patients who underwent “sellar surgery” was deemed at McCabe35 updating McCabe’s experience reported a 100% low risk because a cyst, not a was found). Thus, closure rate with a follow-up of 1.6 to 22 years. The use of during the study period, 6 of 19 (31%) “high-risk” patients these and other local flaps to treat CSF fistulas through were identified to have HPH and underwent VP shunting. an endoscopic approach was subsequently reported.13,36 All patients had successful repair endoscopically. Re- In 1985, Calcaterra37 described the use of free muscle vision surgery was not required. No patient has developed or fascia grafts to treat CSF fistulas using an external a recurrence of the CSF leak at a median follow-up period ethmoidectomy approach, and in 1989, Papay et al.38 de- of 30 months (range, 24–84 mo). Patient 14 had the only scribed an endoscopic technique. Multiple studies fol- surgical complication. This patient developed a small ve- lowed, reporting the use of free grafts or local flaps, or nous infarction of the temporal lobe after the placement of both, for the repair of CSF fistula. Amedee et al.39 re- a VP shunt. This complication probably arose from shifts ported the use of multiple free grafts, including septal in the brain parenchyma caused by the ventricular con- mucosa, fascia, and abdominal fat, in 22 patients who traction and expansion. She developed a mild dysphasia underwent a transnasal microscopic approach for the re- that resolved completely within 4 weeks. pair of CSF leaks. These authors were successful in clos- ing the CSF leaks in all but one patient (95% closure rate). DISCUSSION The only failure occurred in a patient with a spontaneous Literature Review CSF leak arising in the lateral sphenoid sinus, which was A variety of techniques has been reported for the later repaired using an endoscopic technique, requiring a repair of a CSF fistula. In 1952, Hirsch32 described the 70° telescope for its visualization.

Laryngoscope 115: February 2005 Carrau et al.: Cerebrospinal Fluid Leaks 208 Burns et al.40 and Marks41 reported the use of middle cially available preparations are readily available and turbinate mucosa with and without free bone grafts, ob- have a good safety record. taining closure rates of 83% (35 of 42) and 94% (16 of 17), The graft is supported in place with layers of Gelfoam respectively. Similar results were obtained by Anand et or Gelfilm, or both (Upjohn Co., Kalamazoo, MI), followed al.,42 who performed repair in 11 of 12 patients presenting by a packing of bacitracin-impregnated gauze or sponge with CSF fistulas. Their only surgical “failure” was sub- packing. The use of Gelfoam or Gelfilm, or both, prevents sequently repaired using a transcranial approach. Lanza adherence of the packing material to the graft, preventing et al.43 repaired 42 cranial base defects in 36 patients accidental avulsion when the packing is removed (approx- using a mucoperichondrial or mucoperiosteal graft and imately 3 to 7 days after the surgery). septal cartilage (32 of 36) or other various techniques (4 of As an alternative, a vascularized tissue flap may be 36). Only two patients (6%) had recurrence or persistence designed and harvested transnasally using mucoperichon- with a CSF leak (mean follow-up period of 2 years). Weber drium from the middle turbinate or septum. If the fistula et al.44 used free grafts or vascularized flaps, or both, involves the cribriform plate, the mucosa and bone of the whether as an onlay or underlay technique, successfully lateral aspect of the middle turbinate are removed and the repairing the CSF leaks in 42 consecutive patients. Gjuric remaining mucoperiosteal flap is rotated to cover the de- et al.45 also used a variety of materials to endoscopically fect or to cover a muscle-free or fascia-free graft. Similarly, repair the defects of 30 patients with a CSF leak. Only one the mucosa and bone of the lateral aspect of the middle patient (3%) presented with a recurrent leak requiring turbinate may be removed to cover a defect of the fovea repair through a subfrontal approach. ethmoidalis. An additional option includes the removal of Review of the reports in the literature suggest that mucosa from a portion of the ipsilateral septum, removal the choice of the approach and materials used during the of the corresponding septal cartilage or perpendicular endoscopic endonasal closure of CSF fistulas is based on plate of the ethmoid, and rotation of the contralateral the availability of the material and on the experience and mucoperichondrial flap to cover the defect. The flap is familiarity of the operating surgeon with various tech- then supported by Gelfoam or Gelfilm, or both, and niques. The use of bone or cartilage appears to be unnec- bacitracin-impregnated gauze. This type of septal flap is essary with the possible exception of patients presenting the preferred flap for defects of the planum sphenoidale with herniating brain or . Most techniques seem that may not be reached by middle turbinate flaps (i.e., to yield similar results in experienced hands. This is sug- defects that are posterior to the posterior attachment of gested by the results reported in the previous series and the middle turbinate). by other authors1,31,44–46 and has been confirmed by a Exposure of the entire defect is essential. In fact, meta-analysis of the literature by Hegazy et al.1 After exposure of the defect may be a more important factor analyzing all reports in the English literature that were determining the success of the repair than size or site.44 If made up of a series of endoscopic repairs of more than five needed, an external ethmoidectomy approach may be used patients, the latter authors found no significant differ- to complement the endoscopic or microscopic endonasal ences in outcome, regardless of which surgical technique approach. or which homologous material was used for the repair. Sphenoid sinus. The sphenoid sinus can be ap- proached trans-septally or, preferably, through a direct Surgical Technique endoscopic approach such as the one described for pitu- Ethmoid sinus roof and cribriform plate. If a itary surgery.47 Cerebrospinal fluid leaks involving the CSF leak is suspected during endoscopic sinus surgery, sphenoid sinus respond well to obliteration of the sinus. the area in question should be closely examined and the After the leak is identified, the sinus mucosa is thoroughly overlying mucosa reflected away to determine the extent removed, fascia or muscle is placed against the defect, and of injury. A free tissue graft may be used to patch the site the sinus is subsequently obliterated with abdominal free of injury. fat. The anterior wall of the sinus is then reinforced with Suitable grafting materials include fascia lata, tem- a layer of Surgicel and Gelfilm, and the nose is packed poralis muscle, abdominal fat, septal or middle turbinate with a 1⁄2-inch strip that has been impregnated with an- mucosa or composite grafts, periosteum, and perichon- tibiotic ointment. As an alternative, the sphenoid sinus drium. If possible, the dural edges are undermined with a defect can be repaired using calcium phosphate self- small elevator and the edges of the graft are tucked be- setting cement (hydroxyapatite cement) or an equivalent tween the dura and the bone (i.e., inlay graft). If this is not bone cement. Calcium phosphate self-setting cement can possible because of technical difficulties or because the be used for direct repair of a defect, obviating the need for fistula involves a linear fracture that does not expose obliterating the sinus. However, hydroxyapatite is not the dural defect, the graft is placed over the defect well suited for high-flow leaks because the CSF can wash (outside the cranial cavity). Free muscle or fat grafts the cement off the defect before it sets. Furthermore, hy- can also be used as a dumbbell-type plug. Fibrin glue droxyapatite must be covered with vascularized tissue; may be used to increase the adhesiveness of the muscle otherwise, it can become infected with bacteria from the or fascia graft. Autologous fibrin glue does not involve sinonasal tract. the infectious risks of homologous blood product trans- An intraoperative CSF leak arising from the sella fusions. However, in most institutions autologous fibrin turcica during pituitary surgery most often can be re- glue requires several hours of preparation time, which paired by obliterating the sella with free fat and recon- limits its usefulness in the acute care setting. Commer- structing the floor of the sella with a free bone or cartilage

Laryngoscope 115: February 2005 Carrau et al.: Cerebrospinal Fluid Leaks 209 graft harvested during the endoscopic approach.44 Thus, it High-Pressure Hydrocephalus does not require postoperative packing or the removal of Normal intracranial pressure ranges from 5 to 15 cm the entire mucoperiosteum of the sinus. of water when the patient is in supine position. However, Accidental injury to adjacent neurovascular struc- intracranial pressure increases with positional changes, tures is a consideration in patients with CSF fistula at the with Valsalva maneuver, and during rapid eye movement lateral wall of the sphenoid sinus. Adequate visualization (REM) sleep. An increased intracranial pressure (i.e., of this area is critical. Leaks that arise in the lateral recess HPH) is defined as sustained or intermittent pressures of present technical difficulties because of their poor visual- 20 to 30 cm of water.4–8 Post-traumatic, postsurgical, and ization after a traditional sphenoidotomy. Repair often postinfectious hydrocephalus can result from the obstruc- requires ligation of the sphenopalatine artery and exten- tion of the arachnoid villi, thus preventing adequate CSF sion of the sphenoidotomy toward the pterygopalatine reabsorption with subsequent increased intraventricular fossa. pressures. In hydrocephalus after cardiovascular accident Frontal sinus. Cerebrospinal fluid leaks involving and in post-traumatic and postsurgical hydrocephalus, the frontal sinus are usually repaired using a transfrontal the obstruction arises from subarachnoid hemorrhage, sinus approach. The Draf approach, which involves medial whereas in the case of , inflammatory changes widening of the frontal recesses and removal of the supe- are responsible for obstructing the arachnoid villi (Fig. rior nasal septum and inferior frontal sinus septum, may 2).49–54 provide exposure of leaks around the frontonasal recess, Radiation therapy causes vascular changes in the thus allowing an endoscopic repair.48 brain and elevation of CSF protein, scarring, and adhe- sions, all of which may contribute to the impairment of the CSF reabsorption. Likewise, meningitis causes scarring of General Management the CSF cisterns and absorptive sites, thus leading to As previously mentioned, the general principles of chronic hydrocephalus.49–51 management of a CSF fistula include adjunctive measures The incidence of hydrocephalus following a transcra- that may facilitate unhindered closure, avoiding activities nial approach for a tumor or a vascular abnormality that raise the intracranial pressure, such as straining, ranges from 10% to 30%.54,55 A contemporary estimate of leaning forward, or lifting weights greater than 15 pounds. the incidence of CSF leaks following cranial base surgery Other measures include bed rest, stool softeners, elevation of was reported by Janecka et al.55 to be 3.6% in a 30-month the head of bed, sneezing with an open mouth, and avoid- prospective cohort study of 183 cases. By contrast, Sen et ance of nose blowing. “Deep extubation” to prevent straining al.56 reported almost a threefold greater incidence of 8.9% and coughing is employed if the patient is under general following surgery of the cranial base. However, most stud- anesthesia. It is important to avoid positive-pressure mask ies do not include data indicating whether the hydroceph- ventilation. The use of prophylactic antibiotics for the prevention of meningitis in patients with CSF fistulas continues to be controversial. However, the use of antibiotics when the patient has an active sinus infection is warranted. In patients with indwelling lumbar , prophylactic antibiotics are routinely administered and, although the concept is not universally accepted, antibiotics are thought to decrease the incidence of -related in- fections.48 However, the routine use of antibiotics for trau- matic CSF leaks is not of proven efficacy and may select resistant bacteria.49 We do favor the use of perioperative prophylactic antibiotics during the repair of the CSF leak. Antibiotics are continued until nasal packing is removed. A postoperative CT scan without contrast within the first 24 hours after surgery is important to rule out evi- dence of intracranial , parenchyma injury, or ten- sion pneumocephalus. We favor a routine CT scan of the brain, even in the absence of any neurological deficit. Neurosurgical consultation may provide an impor- tant perspective on intraoperative and postoperative man- agement, especially on the need for a CSF drain or a shunt. A lumbar drain is helpful to control intracranial pressure with a designated amount of CSF removed daily based on CSF production. Overdrainage should be avoided because this creates a negative intracranial pressure (i.e., suction effect) that may result in pneumocephalus and Fig. 2. Axial scan of computed tomography scan the brain demon- promote bacterial contamination of the CSF with result- strating acute hydrocephalus after iatrogenic cerebrospinal fluid ant meningitis. fistula.

Laryngoscope 115: February 2005 Carrau et al.: Cerebrospinal Fluid Leaks 210 alus was existent before surgery. Duong et al.57 examined Ford Hosp Med J 1990;38:5–8. the incidence of postoperative hydrocephalus in cranial 8. Levine HL. Functional endoscopic sinus surgery: evaluation, surgery, and follow-up. Laryngoscope 1990;100:79–84. base surgery and found that 8% of patients develop hy- 9. Sterman BM, DeVore RA, Lavertu P, Levine HL. Endoscopic drocephalus in the immediate postoperative period. Half sinus surgery in a residency training program. Am J Rhi- of these patients presented with a postoperative CSF leak. nol 1990;4:207–210. After the CSF fistula repair the increased pressure 10. Duplechain JK, White JA, Miller RH. Pediatric sinusitis: the within the CSF pathways creates a pressure gradient role of endoscopic sinus surgery in cystic fibrosis and other forms of sinonasal disease. Arch Otolaryngol Head Neck promoting the escape of CSF along the path of least resis- Surg 1991;117:422–426. tance. Leakage of CSF is likely to persist or recur after a 11. Salman SD. Complications of endoscopic sinus surgery. Am J seemingly adequate repair if HPH is present. Temporary Otolaryngol 1991;12:326–328. CSF diversion may allow the repair site to form a temporary 12. Wigand ME, Hosemann WG. Results of endoscopic surgery of seal, but the wound will ultimately dehisce in the face of the paranasal sinuses and anterior skull base. J Otolaryn- gol 1991;20:385–390. continuously or continually high CSF pressures. Under 13. Stankiewicz JA. Cerebrospinal fluid fistula and endoscopic these circumstances, a permanent diversion is required to sinus surgery. Laryngoscope 1991;101:250–256. prevent a recurrence of the leak. Our data suggest that 14. Vleming M, Middelweerd RJ, de Vries N. Complications of patients at high risk for HPH (and therefore recurrence of endoscopic sinus surgery. Arch Otolaryngol Head Neck Surg 1992;118:617–623. the CSF leak) can be identified prospectively. Thus, perma- 15. Freedman HM, Kern EB. Complications of intranasal eth- nent CSF diversion can be performed shortly after the re- moidectomy: a review of 1,000 consecutive operations. La- pair, avoiding a leak and the need for a second procedure. ryngoscope 1979;89:421–434. An alternative treatment is to repair all defects and 16. Eichel BS. The intranasal ethmoidectomy: a 12-year perspec- assess the possibility of HPH in only those patients who tive. Otolaryngol Head Neck Surg 1982;90:540–543. 17. Stevens HE, Blair NJ. Intranasal sphenoethmoidectomy: 10- have recurrence with a CSF leak. However, we think that year experience and literature review. J Otolaryngol 1988; prospective identification avoids the risks of meningitis 17:254–259. and pneumocephalus associated with a recurrent CSF 18. MacKay IS. Endoscopic sinus surgery: complications and how leak and the neurological deficits caused by HPH. Acet- to avoid them. Rhinology 1992;14(Suppl):151–155. azolamide, which decreases the production of CSF, may 19. Friedman WH, Katsantonis GP. Intranasal and transantral ethmoidectomy: a 20-year experience. Laryngoscope 1990; have a role in the treatment of some of these patients and 100:343–348. may avoid the need for a VP shunt in some patients. 20. Cumberworth VL, Sudderick RM, Mackay IS. Major compli- cations of functional endoscopic sinus surgery. Clin Otolar- yngol 1994;19:248–253. CONCLUSION 21. Kennedy DW, Shaman P, Han W, Selman H, Deems DA, Evidence of HPH can be detected by elevated CSF Lanza DC. Complications of ethmoidectomy: a survey of pressure as measured by lumbar puncture or by CT scan fellows of the American Academy of Otolaryngology—Head findings, such as dilated temporal horns, and trans- Neck Surgery. Otolaryngol Head Neck Surg 1994;111: ependymal edema. 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