Cerebrospinal Fluid Rhinorrhea

Key Points

Cerebrospinal fluid (CSF) rhinorrhea may be classified as traumatic (>90%) and nontraumatic (<10%). Approximately 80% of all traumatic leaks occur in the setting of accidental trauma, and the remaining traumatic CSF leaks occur after neurosurgical and rhinologic procedures. Nontraumatic etiologies include neoplasms and hydrocephalus.
Idiopathic nontraumatic CSF rhinorrhea has been linked with elevated intracranial pressure. Numerous studies have confirmed an association of idiopathic nontraumatic CSF rhinorrhea with both benign intracranial hypertension and empty sella syndrome.
Clinical presentation of CSF rhinorrhea includes unilateral watery drainage with a characteristic metallic or salty taste, often in the clinical setting of possible etiologic factors.
Confirmation of a CSF leak can be achieved through detection of β-2 transferrin or β-trace protein in nasal secretions.
Cisternogram studies provide diagnosis confirmation and localization information. Both CT cisternography and radionuclide cisternography require lumbar puncture for the administration of tracer agent, whereas MRI cisternography can be achieved solely through specific imaging protocols. Radionuclide cisternography has poor sensitivity and poor spatial resolution. Both CT cisternography and MRI cisternography offer much greater spatial resolution but still require the presence of a relatively large, active leak for reliable detection.
Endoscopic examination after the administration of intrathecal fluorescein can confirm a CSF leak diagnosis and indicate its location. Dilute fluorescein must be used; serious neurologic sequela have been reported after higher intrathecal doses of this agent.
Endoscopic repair has emerged as the preferred modality for most cases of CSF rhinorrhea requiring operative repair. During endoscopic repair, the leak site is identified and then closed with autogenous graft materials (fascia, free bone graft, fat), allograft (acellular dermal allograft), and/or xenogeneic collagen dural substitutes. A free mucosal graft is typically placed over these materials, and the reconstruction is secured with surgical sealant and resorbable and nonresorbable packing material. For high-flow leaks and/or large dural defects, vascularized mucosal flaps may be preferentially considered.
Traumatic CSF leaks likely resolve with conservative measures (lumbar drainage and bedrest); operative repair is reserved for those cases in which these measures fail or in which massive injury requires urgent formal operative exploration and repair.
CSF leakage recognized at the time of surgery should be repaired during that procedure. CSF rhinorrhea that develops after surgery may be managed conservatively initially, but most patients will require operative repair.
Nontraumatic CSF rhinorrhea is unlikely to resolve spontaneously. After excluding potential etiologic factors (brain tumor), operative repair is warranted.
Studies have not confirmed a positive benefit from the routine use of lumbar drains in the immediate postoperative period after endoscopic CSF leak repair. The use of lumber drains may be considered in select patients with suspected or confirmed increased intracranial pressure.

Introduction

Cerebrospinal fluid (CSF) rhinorrhea results from a direct communication between the CSF-containing subarachnoid space and the mucosalized space of the paranasal sinuses. Because it may serve as a path for the spread of bacterial pathogens and other microorganisms, CSF rhinorrhea may lead to meningitis and intracranial infections, which carry significant morbidity even nowadays. In addition, the skull base defect through which CSF drains may provide a route for the development of pneumocephalus and secondary brain compression. Although CSF rhinorrhea is a simple concept, its diagnosis and localization may be problematic; fortunately, contemporary strategies currently provide a more direct means of diagnosis and localization. Over the past three decades, the optimal treatment strategy has undergone significant evolution as minimally invasive, endoscopic techniques have gained acceptance and supplanted more traditional techniques, which require external incisions and/or craniotomy.

Historical Perspective

CSF rhinorrhea was first reported in the 17th century. In the early 20th century, Dandy reported the first successful repair, which used a bifrontal craniotomy for placement of a fascia lata graft. Although this surgical strategy provided direct access for the repair, reported failure rates were quite high and the procedure entailed the morbidity of craniotomy. In fact, reported recurrence rates were as high as 27%, and in one series only 60% of leaks were successfully repaired.

Extracranial approaches were introduced in the mid-20th century. In 1948, Dohlman presented a patient whose CSF leak was repaired through a standard naso-orbital incision. Several years later, Hirsh reported the successful closure of two sphenoid sinus CSF leaks through a pure endonasal approach. In 1964, Vrabec and Hallberg described the repair of a cribriform defect through an endonasal route. All of these endonasal procedures were completed before the advent of surgical nasal endoscopy.

Endoscopic approaches were introduced and popularized in the 1980s and early 1990s. Both Wigand and Stankewicz described closure of incidental CSF leaks during endoscopic sinus surgery. In 1989, Papay et al. introduced rigid transnasal endoscopy for the endonasal repair of CSF rhinorrhea, and in 1990, Mattox and Kennedy presented another series of cases in which the CSF rhinorrhea was addressed under endoscopic visualization. Since then, numerous series have been published, and endoscopic repair has emerged as a mainstay of surgical management.

Classification

Box 48.1 summarizes a classification system for all cases of CSF rhinorrhea. This approach is based upon the established pathophysiology of CSF rhinorrhea and has important clinical implications for the selection of treatment strategies, as well as patient counseling about prognosis.

Box 48.1

Cerebrospinal Fluid Rhinorrhea Classification

I

Traumatic

A

Accidental

1
Immediate
2
Delayed

B

Surgical

1
Complication of neurosurgical procedures
- a
  Transsphenoidal hypophysectomy
- b
  Frontal craniotomy
- c
  Other skull base procedures
2
Complication of rhinologic procedures
- a
  Sinus surgery
- b
  Septoplasty
- c
  Other combined skull base procedures

II

Nontraumatic

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