Long-term Thalamic Deep Brain Stimulation for Essential Tremor: Clinical Outcome and Stimulation Parameters.

BACKGROUND: The reasons underlying the loss of efficacy of deep brain stimulation (DBS) of the thalamic nucleus ventralis intermedius (VIM-DBS) over time in patients with essential tremor are not well understood. METHODS: Long-term clinical outcome and stimulation parameters were evaluated in 14 patients with essential tremor who underwent VIM-DBS. The mean ± standard deviation postoperative follow-up was 7.7 ± 3.8 years. At each visit (every 3-6 months), tremor was assessed using the Fahn-Tolosa-Marin tremor rating scale (FTM-TRS) and stimulation parameters were recorded (contacts, voltage, frequency, pulse width, and total electrical energy delivered by the internal generator [TEED 1sec]). RESULTS: The mean reduction in FTM-TRS score was 73.4% at 6 months after VIM-DBS surgery (P < 0.001) and 50.1% at the last visit (P < 0.001). The gradual worsening of FTM-TRS scores over time fit a linear regression model (coefficient of determination [R2] = 0.887; P < 0.001). Stimulation adjustments to optimize tremor control required a statistically significant increase in voltage (P = 0.01), pulse width (P = 0.01), frequency (P = 0.02), and TEED 1sec (P = 0.008). TEED 1sec fit a third-order polynomial curve model throughout the follow-up period (R2 = 0.966; P < 0.001). The initial exponential increase (first 4 years of VIM-DBS) was followed by a plateau and a further increase from the seventh year onward. CONCLUSIONS: The current findings suggest that the waning effect of VIM-DBS over time in patients with essential tremor may be the consequence of a combination of factors. Superimposed on the progression of the disease, tolerance can occur during the early years of stimulation.

A single-center, long-term study of spinal dural arteriovenous fistulas with multidisciplinary treatment.

Spinal dural arteriovenous fistulas (SDAVF) are the most frequently occurring vascular malformations of the spinal cord but their optimal treatment remains contentious. We retrospectively analyzed 19 consecutive patients treated between 1996 and 2007. Endovascular embolization was considered the first treatment option for nine patients. Ten patients did not fulfill the endovascular indications and underwent surgery. Four patients required a second treatment with surgery: three following failed embolization and one following surgery. Clinical outcomes were assessed using the Aminoff-Logue disability scale (ALS). The mean follow-up time was 36 months (range=4-103 months). At follow-up, 79% of patients showed stabilization or improvement on the ALS. The overall efficacy of embolization was 55.6%, compared to 100% with surgery (p=0.03). Multidisciplinary treatment with embolization or surgery offers good long-term results. Whenever embolization does not ensure a complete closure of the venous side of the fistula, surgery should be considered as the first treatment because of its lower late recurrence rate.

Massive epistaxis resulting from an intracavernous internal carotid artery traumatic pseudoaneurysm: complete resolution with overlapping uncovered stents.

Blunt traumatic injuries of the intracranial carotid arteries can result in pseudoaneurysm formation. A pseudoaneurysm of the intracavernous carotid artery may rupture into the cavernous sinus, causing life-threatening epistaxis. We report a case of intracavernous traumatic psedoaneurysm presenting with delayed massive epistaxis. The endovascular treatment with overlapping self-expanding stents achieved complete exclusion of the pseudoaneurysm with preservation of the intracavernous carotid artery.