Emergent treatment is warranted, however, when the risk of permanent visual impairment is imminent, or when cortical venous hypertension predisposes to intracranial hemorrhage. Treatment may be challenging due to the small size of the feeding arteries often arising from the cavernous internal carotid artery (ICA), the risk of inadvertent embolization of external to internal carotid artery collaterals, and the inconsistent and often discontinuous nature of the venous system. Endovascular treatment options include transvenous and transarterial embolization. Endovascular treatment is sometimes combined with a surgical approach to the engorged orbital veins.
Abducens nerve palsy is the most common complication after transvenous embolization (TVE) for cavernous sinus dural arteriovenous fistula. Abducens nerve palsy is reported to have a good prognosis after the symptoms have been alleviated. The purpose of this study was to identify cases of delayed abducens nerve palsy after successful TVE and discuss the physiological mechanisms responsible for this unusual complication.
Between 1991 and 2012, TVE was performed for 73 patients. The patients were evaluated for clinical symptoms every 12 months during the follow-up period. Patients' data and information about abducens nerve palsy were obtained from clinical records retrospectively.
Abducens nerve palsy newly developed in 4 (5.5%) of 73 patients at 3-65 months after TVE. All four patients with delayed abducens nerve palsy were followed up for 8-84 months. However, delayed abducens nerve palsy persisted in all four patients. In these four patients, the shunt points were posterior cavernous sinus. The average coil length used for four patients was 206.5 ± 43.1 cm (n = 4), and the average coil length used for patients without delayed abducens nerve palsy was 112.8 ± 38.8 cm (n = 69).
The possibility of delayed abducens nerve palsy should be kept in mind, especially in the patients who were treated with transvenous coil packing in the posterior part of the cavernous sinus. Furthermore, our results suggest that long-term follow-up care is important for these patients, even after complete neurological and radiological recovery was attained 1).