Imaging is an important component in the investigation of unilateral watery rhinorrhoea suspicious of cerebrospinal fluid (CSF). Whilst the demonstration of the presence of beta 2 transferrin confirms that CSF is present it may prove difficult to demonstrate the exact site of origin. Fine detail coronal computed tomography (CT) with sections of 1-2 mm thickness through the anterior skull base may show small dehiscences and fractures. The commonest site for congenital dehiscences is the cribriform niche adjacent to the vertical attachment of the middle turbinate anteriorly and the superior and lateral walls of the sphenoid posteriorly. In the presence of frequent or constant CSF rhinorrhoea a CT cisternogram can be helpful in defining the exact site of the leak. Magnetic resonance imaging (MRI) is reserved for defining the nature of soft tissue i.e. inflammatory tissue, meningoencephalocele or tumour. Finally, per-operative intrathecal fluorescein is helpful when imaging does not prove positive. A management algorithm for CSF rhinorrhoea is presented.

Cerebrospinal fluid (CSF) rhinorrhoea is leakage of fluid from the subarachnoid space to the frontal, sphenoidal or ethmoidal sinuses, and may occur spontaneously. The authors present the first reported case of bilateral spontaneous CSF rhinorrhoea. Bony defects on both sides of the cribriform plate were identified using endoscopic and radiological techniques, and the CSF fistula was closed endoscopically. The aetiology, diagnosis and contemporary surgical treatment of spontaneous CSF leaks is discussed. Endoscopic repair was successful in this case, and in view of the high success and low reported complication rates this surgical approach should be considered for treatment of spontaneous CSF rhinorrhoea.

We present an unusual case of generalized erosion of the skull base. We have not found a similar case reported in the world literature. The presenting symptom was spontaneous cerebrospinal fluid (CSF) rhinorrhoea which arose from a bony defect associated with herniation of the right temporal lobe into the sphenoid sinus. We discuss the management of such a case including imaging of the skull base and the endoscopic repair of the bony defect.

In the past cerebrospinal fluid (CSF) leaks were managed via a craniotomy with intradural repair. With the advent of endoscopic sinus surgery, transnasal repair has become more popular. The comparatively low morbidity and high success rate of endoscopic repair has made it the treatment of choice for CSF leak repair. As more surgeons practice endoscopic sinus surgery, the incidence of iatrogenic CSF leaks has increased. It is important that endoscopic sinus surgeons be aware of the techniques for closing such leaks. The aim of this study is to present a new technique for the endoscopic repair of CSF leaks. Since the technique was devised the authors have used the technique on six patients. All patients had lumbar drains inserted and five patients had intra-thecal fluorescein inserted for location of the leak. All repairs have been successful with an average follow-up of 13 months. The technique consists of introducing a fat plug with a specifically secured vicryl suture into the intradural space and placing traction on the suture to seal the defect much as a bath plug seals a bath. There were no complications in any of the patients either intra- or post-operatively. The difficulties and possible complications of the technique as well as the use of a lumbar drain and intra-thecal fluorescein are discussed.

A radiological study of skull base anatomy was performed in patients presenting with primary spontaneous CSF rhinorrhoea. Radiology correctly identified the fistula site in 90 per cent of cases. Contrast CT imaging was found to be the most suitable technique for identifying the presence and site of CSF fistulae. However, pre-contrast bony dehiscences were identified in all patients leaking from the cribriform plate region. More significantly, all of these patients showed deviation of their crista galli, a radiological sign hitherto unreported. These findings support the theory that congenital bony dehiscence is the aetiological basis for this condition. The importance of radiology in the management of this condition is emphasized.