Traumatic Cerebrospinal Fluid Leaks

The present study aimed to investigate outcomes following open surgery for extensive skull base ORN. Open surgery through a personalized sequential approach was employed to deal with five cases of extensive skull base ORN. Two patients with mild cases underwent regional debridement and sequestrectomy, and three patients with severe cases underwent extensive resection with reconstruction using free anterolateral thigh (ALT) flap. Biological glues and vascularized flaps were used for obturation of the skull base bony defect to prevent postoperative cerebrospinal fluid (CSF) leakage. The infections were controlled by antibiotic administrations which strictly followed the principles of antimicrobial stewardship (AMS). As results, both regional debridement plus sequestrectomy and extensive resection achieved satisfied outcomes in all patients. No severe complications and delayed hospitalization occurred. During the follow-up period (8–19 months), all patients were alive, pain free, without crusting or purulent discharge, and no sequestration or CSF leakage occurred. In conclusion, a personalized sequential approach including open surgery, pedicled/vascularized free flap reconstruction and AMS was advocated for patients with extensive skull base ORN.

On successful surgical repair of traumatic, iatrogenic, or spontaneous anterior skull base defects with cerebrospinal fluid (CSF) rhinorrhea, appropriate postoperative management is imperative to prevent failure of the repair or recurrence of fistulae. Possible adjuncts to surgical repair include activity and position restrictions, acetazolamide, temporary lumbar or ventricular drainage, and permanent CSF diversion with placement of a ventricular or lumbar shunt. The choice of postoperative adjunct(s) should be guided by the surgeon’s confidence in the surgical repair, the site and size of skull base defect repaired, and patient factors such as body mass index and suspicion for raised intracranial pressure. The risks of adjunct management should also be weighed against the benefits for preventing recurrent CSF leakage.

The first description of cerebrospinal fluid (CSF) from the nose dates back to the second century by Galen of Pergamon. The term CSF rhinorrhea appeared for the first time in 1899 in a series of patients presenting with nasal CSF leaks of various causes. Since then, several classifications of CSF rhinorrhea have been proposed. The most useful classifications categorize CSF leaks according to their cause, including traumatic, spontaneous, meningoencephaloceles and meningoceles, and iatrogenic leaks. Recent data indicate that spontaneous CSF leaks are a commoner entity than previously thought. The first endoscopic approach to repair of an anterior cranial base CSF leak was published in 1981. Over the following decades, there has been a shift from open intracranial management toward minimally invasive endoscopic techniques, which have become the gold standard for CSF leak repair. With the advances in endoscopic endonasal techniques, imaging, and navigation together with a broad variety of closure options, failure rates have dramatically decreased to less than 10%. Initially, the first endoscopic CSF leak closure series were done on small leaks; however, it is now common for otolaryngologists to reconstruct large skull base defects endonasally.

Iatrogenic skull base injury resulting in cerebrospinal fluid (CSF) rhinorrhea occurs during rhinologic and neurosurgical procedures. Identification of an iatrogenic skull base defect may occur at the time of injury or in a delayed setting. Symptoms of iatrogenic CSF rhinorrhea include unilateral continuous rhinorrhea that worsens with head posturing and Valsalva maneuver. In settings of delayed identification, updated workup and imaging should be performed before attempted repair. The most common site of iatrogenic injury is the ethmoid roof followed by the sphenoid skull base. The goal of repair is to reestablish a barrier between the nasal cavity and intracranial space to decrease the risk of major complications, such as meningitis, intracranial abscess, and pneumocephalus, from developing. For most anterior skull base iatrogenic defects, endoscopic approaches are the criterion standard for repair. Limitations to purely endoscopic approaches include high posterior table injuries or posterior table injuries located laterally over the orbits. Successful repair requires localization of the defect, preparation of the defect site, and repair using single or layered reconstruction depending on defect size, location, and whether the leak is high or low flow. Success rates of iatrogenic defect repair exceed 90% using a variety of grafting materials and techniques. Routine use of a lumbar drain is not advocated, and long-term follow-up is important to ensure successful repair and that sinuses maintain patency.

The imaging approach to cerebrospinal fluid rhinorrhea requires an adaptive approach based in part on whether the leak is active at the time of imaging, patient limitations and preferences, and what is available at your institution. This chapter discusses the more commonly used techniques of nuclear medicine cisternography, high-resolution computed tomography, CT cisternography, magnetic resonance imaging (MRI), and contrast-enhanced MRI cisternography in detail. Practical considerations and institutional variation are also described. This should allow you to know where to begin and what supplemental imaging to consider based on the patient circumstances and results of initial imaging before potential intraoperative management.

The lateral skull base is comprised of the squamous and petrous temporal bones. Fractures through the petrous pyramid account for approximately 20% of all traumatic skull fractures. They can be classified into two types, based upon the involvement of the otic capsule, otic capsule sparing, and otic capsule disrupting. The eloquent structures within and surrounding the petrous temporal bone lead to significant morbidity associated with these fractures. They can lead to cerebrospinal fluid (CSF) leak, facial nerve injury, hearing loss (both conductive and sensorineural), and cerebrovascular injury. Early recognition of a lateral skull base fracture, based upon clinical signs (e.g., Battle's sign) and imaging, is key to further management. Examination of the external ear for CSF leak or extruded brain parenchyma and examination of facial movement are the most important physical exam findings to determine need for early surgical intervention. Facial weakness is treated conservatively for the first 7 days after injury. Acute-onset, complete facial weakness, though, is a poor prognostic sign and can be an indication for early surgical intervention to decompress the nerve. Most CSF leaks will resolve spontaneously within the first week after injury and will not require surgical intervention. Hearing loss is managed conservatively with delayed audiogram. Sensorineural hearing loss has a poor prognosis for recovery. Persistent conductive hearing loss for more than 6 months can be treated with exploratory tympanotomy. Cerebrovascular injury is treated with antithrombotic therapy. In conclusion, the timing of onset of facial weakness is the most important determining factor in surgical intervention, while most sequelae of lateral skull base trauma can be treated conservatively.