Tentorial dural arteriovenous fistula presenting with various visual symptoms related to anterior and posterior visual pathway dysfunction: case report.

OBJECTIVE AND IMPORTANCE: Dural arteriovenous fistulae (DAVFs) not directly shunting into the cavernous sinus are an infrequent cause of visual dysfunction. An unusual case of a tentorial DAVF associated with visual symptoms related to dysfunction of the anterior and posterior visual pathway is presented. CLINICAL PRESENTATION: A 38-year-old woman with a history of long-standing bilateral proptosis experienced a sudden onset of headache and visual disturbances. Ocular examination revealed bilateral episcleral and retinal venous congestion, optic disc paleness, right superior homonymous quadrantanopsia in both eyes, and concentric narrowing of the visual field of the right eye. Angiography revealed a DAVF supplied by a falx branch arising from the left vertebral artery and both middle meningeal arteries, which drained directly into the markedly dilated vein of Galen via the basal vein of Rosenthal and the cavernous sinus into both superior ophthalmic veins. INTERVENTION: Endovascular treatment was performed in two consecutive sessions by transarterial embolization with n-butylcyanoacrylate, which resulted in occlusion of the fistula and complete clinical cure, confirmed at the 6-month follow-up examination. CONCLUSION: Various neuro-ophthalmological findings may be caused by an arteriovenous lesion remote from the optic organ as a result of rerouting of venous drainage compromising the visual pathway at different locations. Transarterial embolization of a DAVF may result in complete cure if advantageous arterial anatomy allows for flow control and occlusion of the fistulous connection with liquid adhesives.

Results from a European clinical investigation of the Nucleus multichannel auditory brainstem implant.

OBJECTIVE: This study was designed to investigate the perceptual benefits and potential risks of implanting the Nucleus(R) multichannel auditory brainstem implant. DESIGN: Between September 1992 and October 1997 a total of 27 subjects received a Nucleus 20- or 21-channel Auditory Brainstem Implant (ABI). All subjects involved in the trial had bilateral acoustic tumour as a result of neurofibromatosis type 2 (NF2) resulting in complete dysfunction of the VIIIth nerve. The study used each subject as their own control without a preoperative baseline because residual hearing, if existing, was destroyed at surgery by tumour removal. A battery of speech tests was conducted to evaluate each patient's performance and communication abilities. Tests were conducted, where possible, in the auditory-only, visual-only, and auditory-visual conditions at 3 days postoperatively (baseline), at 3-mo intervals for the first year and every 12 mo thereafter. A subjective performance questionnaire was administered together with an extensive neurological examination at each test interval. RESULTS: 27 subjects involved in this trial were successfully implanted with a Nucleus ABI. One subject died 2 days postoperatively due to a lung embolism unrelated to the device. Twenty-six subjects underwent device activation and all but one patient received auditory sensation at initial stimulation (96.2%). On average 8.6 (+/-4.2) of the available 21 electrodes were used in the patients' MAPs. Performance evaluation measures showed that the majority of users had access to auditory information such as environmental sound awareness together with stress and rhythm cues in speech that assist with lipreading. Although most subjects did not achieve any functional auditory-alone, open-set speech understanding, two subjects from this series (7.4%) did receive sufficient benefit to be able to use the ABI in conversation without lipreading. CONCLUSIONS: Although the medical risks and surgical complexity associated with ABI device implantation are far greater than those for a cochlear implant, the clinical results from this trial show that the Nucleus multichannel ABI is capable of providing a significant patient benefit over risk ratio for subjects suffering loss of hearing due to bilateral retrocochlear lesions.