• CT scan of a patient with a defect in the posterior ethmoid skullbase.
In the past surgery for closure of CSF defects required an open approach which sometimes included a craniotomy. A craniotomy requires a very large incision on the scalp and removal of the skull bones. The front part of the brain then has to be retracted away to identify the area of the defect. This is then closed with a “pericranial” flap. The surgery though has a good success rate, is also associated with significant morbidity and prolonged hospital stay. In the past 20 years or so endoscopic techniques to repair these skull base defects have been popularised and have an equally good success rate. As the techniques are minimally invasive, there are no incisions made on the scalp or the face, the recovery is faster and the hospital stay shorter. The challenge is to localise the defect pre-operatively using imaging studies such as the CT scan and MRI scan as seen above. Occasionally, the defect may be so small that it may not be identified on the imaging studies. In such cases the use of a dye is useful in identifying the location of the defect. The dye called “fluorescein” is injected in the CSF through a lumbar puncture (intrathecal) before the surgery. Once the defect is identified it can be repaired using tissue taken from the patients own body. This may include fat, cartilage and mucosa. The repair is supported with nasal packing which can be removed in 2 – 3 days. The surgery is done under general anaesthesia and may take about one and half to 2 hours.