Introduction: Carotid-cavernous fistulas (CCF) are anomalous communications between the carotid arterial and carotid venous circulation of the cavernous sinus. The arterio-venous shunt leads to increased congestion of the orbit and causes the characteristic clinical picture typical of this condition; medusa's head, proptosis, raised intra-ocular pressure and tinnitus.
Development: Classically, acute onset of these signs after trauma has been considered to be due to CCF. However, 25% of CCF are low flow and have an insidious clinical course which is concealed and difficult to diagnose. Primary search depends initially on the use of ultra-sound (Eco-B and Eco-Doppler). In doubtful cases vascular study is done using non-invasive methods such as angio-CT, angio-MR and Divas. Intra-arterial angiography is left until the preoperative study is done.
Conclusions: Whilst 90% of medium and high flow FCC require neurosurgical treatment for the gravity of the symptoms, only 25% of the low flow FCC require it. The latter are initially treated conservatively.