In recent years we have seen the establishment of the ESS as a technique of choice for closure of CSF leak, seen as a less invasive technique with less morbidity and mortality, excellent view of the surgical field, and a higher success rate (about 95%), replacing the usual techniques, such as transcranial and extracranial interventions that had a success rate of 70% with significant morbidity (anosmia was permanent sequel) [9
]. It is a common surgical approach in the surgeon’s nose that does not require specific instruments for intervention. However, it is necessary to get a good workout in endonasal endoscopic techniques in order to obtain good surgical results and and avoid complications. And one way to achieve these objectives is the organization of neurosurgeons and otolaryngologists teams to share experiences and knowledge to the management of skull base pathology [10
The presence of CSF rhinorrhea entails a significant risk to the patient’s life [3
]. The clinical confirmation should be performed by nasal inspection and determination of CSF markers such as β2-transferrin, which has high specificity and sensitivity [11
], or β-trace protein, economical and highly specific with high sensitivity. A CSF fistula entails a risk of bacterial meningitis in the long term, approximately 40% [12
], situation may worsen when the healing of the repair is insufficient, when you leave a lumbar drain, or the administration of prophylactic antibiotics that increase the bacterial resistance and promote infection [3
The pneumocephalus is other major complication in the anterior skull base defects, and are due to direct contact between nasal cavity and the intracranial cavity. The rapid onset of headache and neurological signs, changes in mental status to coma should alert. The two patients who had a severe pneumocephalus, CT confirmed the presence of intracranial air and the fistulous tract through the ethmoid roof into the nasal cavity. It is caused by either a ball-valve mechanism that allows air to enter but not to exit, or by CSF leakage, which creates a negative pressure with subsequent air entry [13
]. The closures of both fistulas were performed with an underlay technique, placing a mucoperichomdrium combined with cartilage graft, and seal with fibrin glue without lumbar puncture. The follow-up CT certified the progressive resolution of pneumocephalus confirmed the closure of CSF leaks.
The identification of the site is necessary for successful surgical repair. CT, with and without contrast, and nasal endoscopic exploration are the most common form of locating the fistula, and when not displayed properly, CT cisternography is a helpful test [14
In the surgical iatrogenic CSF fistula, need to clean and control the nasal bleeding that occurs in the surgical field to locate and properly close the fistula. It should be noted the risk that exists with the use of microdebrider blade in FESS, due to the fast and aggressive cut that exposes the skull base to iatrogenic injury, in this area is common to use less aggressive material but we must remember that the skull base lesions can occur with any instrument or technique [1
]. We noted in one patient a large iatrogenic injury at the ethmoid region after endoscopic nasal surgery as a result of using a microdebrider blade, which was repaired in a second attempt. In general, iatrogenic CSF fistula after FESS are small, and as previously mentioned, the size of the defect is the factor determinant, for the need the additional layers and supporting structures.
The observation in one of our patients with spontaneous CSF fistula the presence of idiopathic intracranial hypertension, has led us to consider the need for a previous study as the search for an empty sella syndrome [15
]. The presence of obesity by body mass index [10
], or observation intracranial hypertension by ophthalmologic study.
There have been many materials used for sealing of the fistula, and we have resorted to many. The mucoperichondrium, and cartilage in our patients were able to seal the fistula, and we agree with Hegazy [6
], which reports that the material used in the closure of the fistula is not important in the success of the intervention, even in large defects of choosing a suitable material is important [17
]. Most authors recommend obtaining grafts of the nasal passages that can be easily obtained from the turbinates, nasal septum or nose floor, but if you cannot get, the temporalis fascia is still the most appropriate place. Either way, each fistula should be treated in a unique way [18
], and the surgeon must know the different options to solve the problem.
The controversy lies in the technique of graft placement. Onlay and underlay techniques are used depending on the size of the fistula, and both have similar results when used properly [19
]. Determine the size of the fistula is important. For this we use curettes of different sizes than we use in pituitary surgery trying, to cut the graft to form double defect. If necessary, use a layer of septal cartilage to provide better management when inserted into the defect. We prefer to perform the underlay technique, as a safe technique, because the base of the skull is that supports the graft in place. In addition, to prevent a brain herniation, place a piece of cartilage that gives it strength to clogging with perichondrium. In small leak where it is technically impossible “underlay” technique, we perform the onlay technique. It is widely accepted that large defects are preferably treated by underlay technique, and we recommend them to be placed into the fistula by a piece of cartilage, which can be obtained from the nasal septum. This gives strength to the graft of perichondrium and avoids brain herniation. It is important to promote osteogenesis curettage is performed with a curettes of bone defect edges that we will close. Onlay techniques is reserved for small defects, or when the underlay technique is not possible.
We do not use intrathecal fluorescein for serious complications that can arise. We believe that lumbar drainage may increase morbidity and hospital stay. To observe the leak during surgery, we encourage increased intracranial pressure by increasing the pressure at the abdomen that allows us to locate the CSF leak as a stream of clear liquid and transparent.
Like others authors [17
], we reserve lumbar drainage for patients with elevated intracranial pressure and the conservative measures, such as bed rest, elevation of the head, avoidance of straining activities [10
], is sufficient to ensure the sealing of the leak. An area of controversy regarding management involves the use of CSF diversion techniques such as lumbar drainage. Some authors hypothesize that regardless of the reconstruction technique, patients with increased CSF pressure are at increased risk of persistent or recurrent CSF leak at the reconstruction site or elsewhere along the skull base. While some groups do not favor the use of perioperative lumbar drainage because closure rates may not improve and fear of eliciting pneumocephalus [21
] others use lumbar drainage to measure intracranial pressure to select patients for permanent CSF diversion [5
The use of antibiotics in skull base surgery is controversial, however the penicillin and macrolides are used in the postoperative phase of endoscopic sinus surgery, and although the risk of meningitis must be counterbalanced with the risk of resistance to antibiotics, we recommend an antibiotic coverage in cases of iatrogenic fistulas. Like other authors we recommend the use of ceftriaxone [15
]. Hospitalization should be extended only the time that patient is a monitored and intravenous antibiotic, although some authors recommend the patient was discharged one day after the intervention [19