Cerebrospinal Fluid Leaks (CSF) and Meningoencephaloceles
Mount Sinai has been at the forefront in the minimally invasive treatment of cerebrospinal fluid leaks (CSF) that originate from the nose. The Mount Sinai Hospital was the first institution in the country to conduct a course in sinus surgery and the institution’s commitment to excellence in this field continues today. Additionally, we were one of the first institutions to have implemented a noninvasive diagnostic technique to help localize CSF leaks that originate from the nasal cavity; thus avoiding the need for more invasive preoperative studies prior to treatment. Our multidisciplinary approach and expertise in the management of CSF leaks have enabled us to treat this condition with a very high success rate combined with minimal complications.
About CSF Leaks
Cerebrospinal fluid bathes the brain and spinal cord and acts as a cushion to protect these areas. CSF leaks occur through a communication between the lining of the brain and the nose. These communications may occur spontaneously or result from trauma or prior sinonasal surgery. The spontaneous leak occurs in patients who have an elevation in their CSF pressure similar to someone who has high blood pressure. This elevation in pressure causes fluid to leak into the nose since the brain and nose are in close proximity.
At times in addition to fluid either the covering of the brain (meningocele) or some of the brain (encephalocele) itself may herniate into the nose or ear. These conditions can still be managed with a minimally invasive technique and are important to seal quickly.
Diagnosis of CSF Leaks
The classic presentation of CSF leaks is the expression of clear, watery drainage from nose. This occurs usually on one side; however if fluid drains into the back of the throat there may be a salty taste. Drainage also tends to increase when bending over or straining. Some patients may present with an unexplained episode of meningitis or headaches when sitting upright.
The first step in making the diagnosis is collecting a small sample of fluid and testing it in the lab for beta-2 transferring - a substance only found in CSF. Once the fluid is confirmed to be cerebrospinal fluid, the next step is to locate the site of the leak. In some cases, a CSF leak in the nose may originate in the ear. This is because the ear is connected to the nose through a structure called the eustachian tube. Fluid collecting in the middle ear passes through this tube in to the back of the nose and usually drains into the throat.
Localization of a CSF leak is done through imaging studies such as a CT scan and MRI. At Mount Sinai we perform a novel technique where we superimpose the CT and MRI to find the site of leak. This avoids the need for more invasive studies that require a lumbar puncture (needle in the back) that have been done in the past.
Treatment of CSF Leaks
The treatment of CSF leaks requires surgical closure of the communication between the brain and nasal cavity. At Mount Sinai all patients with CSF leaks receive a full consultation at our Skull Base Surgery Center. Since Mount Sinai is a multidisciplinary center specializing in the treatment of skull base pathology, consultations with neurosurgeons and at times neuro-ophthalmologists are usually obtained. Imaging studies are coordinated and at times can be arranged prior to your consultation with our center. Treatment of CSF Leaks include:
- Conservative Management: in the event of trauma such as a motor vehicle accident, small leaks may close spontaneously with bed rest and avoidance of strenuous activity and nose blowing. Some studies, however, have reported up to a 20 percent risk of developing meningitis after a traumatic CSF leak especially in the setting of sinus surgery. For this reason we do not advocate this treatment option, but it is important to share.
- Endoscopic Surgical CSF Leak Closure: this is the treatment of choice and has a 97 percent success rate and a complication rate of less than 1 percent. We perform a two surgeon minimally invasive technique that avoids the need for facial incisions. Tissue from within the nose is used to seal the defect and the sinuses adjacent to the area are opened in order to avoid problems with chronic sinusitis in the future. Patients are discharged home in one to two days and are followed closely in the office to ensure that their nasal cavity heals well.
- Adjunctive Treatment: patients with spontaneous leaks may require procedures such as a shunt to control a problem with elevated pressure around the brain. This is done to avoid the possibility of future CSF leaks in other areas as well as the complications of elevated intracranial pressure related to vision and hearing.