Leakage of cerebro-spinal fluid (CSF) results from an abnormal communication between the subarachnoid space and the extra-cranial space. Persistent CSF leaks (CSFL) usually imply the development of a CSF fistula. There are various reasons for the development of such a fistula, including trauma, tumors of the skull base, and congenital defects. Such fistulae may also develop following skull base surgery, post-traumatically or spontaneously [11, 12, 19, 27]. When CSFL involves the anterior skull base, it usually presents as rhinorrhea [11, 27].
Once a fistula has been identified and localized, treatment of the leak is pursued. In some of the cases, CSF diversion – temporary or permanent, may be considered. When CSF diversion is not used, or is unsuccessful in alleviating the CSFL, an anterior skull base reconstruction (ASBR) is employed. ASBR may be approached by the endonasal approach or trans-cranially, via a craniotomy. Factors affecting the approach decision include the etiology of the leak, the exact location of the leak (if located), the flow of the leak, the estimated size of the fistula and other considerations. There has been ample research aimed at describing the success rate of ASBR: Failure rates have ranged between 0–30% in different series, on first attempt of reconstruction, and 0–14% on second attempt [2, 3, 7–9, 13, 14, 17, 22, 26].
Open intracranial approaches, or non-endoscopic endonasal accesses have historically been used for the treatment of ASBR, but in recent decades these have largely been replaced by Endonasal Endoscopic approaches (EES) that show high success rate and low morbidity [4–6, 9, 10, 18, 21, 23, 24].
There is a variety of materials available in EES to obstruct CSFL. These include fat, bone, vascularized grafts, fascia lata, muscle, and other, artificial materials. These include fibrin glues and various sealants to secure these materials in place [13, 20, 25, 27].
The size of the defect is a significant determinant of success rates in ASBR. A major challenge of ASBR in case of large defect or high flow CSF leak is to overcome the CSF pressure and brain pulsation, that may push the implanted graft to protrude extracranially [1, 16, 28]. Several techniques have been described to overcome this problem: Warmold and McDonogh described a fat ‘‘bathplug’’ closure for small (1 cm) cranial defects, and entailed a success rate of 94% from the first attempt and a 100% success from the second attempt. , Luginbuhl et al proposed a bilayer button technique for a high-flow CSF leak, with 10% postoperative CSF leak . Leng et al suggested the ‘‘gasket seal’’ technique and reported no postoperative leak, albeit in a small cohort of 10 patients .
The purpose of this paper is to describe our single-center experience in the EES approach for management of CSF leak. Herein we present the use of a novel technique, we named the "corkscrew technique", and evaluate the outcomes in those treated with the corkscrew technique (CST) applied in an EES procedure, for ASBR.