The role of vagus nerve stimulation in the treatment of refractory epilepsy: clinical outcomes and impact on quality of life.

BACKGROUND: Vagus nerve stimulation (VNS) is used as a complementary therapy to pharmacological treatment in patients with refractory epilepsy. This study aims to evaluate the efficacy of VNS in reducing seizure frequency, severity, and duration; reducing the number of antiepileptic drugs administered; and improving patients' quality of life. MATERIAL AND METHODS: We analysed the clinical progression of 70 patients with refractory epilepsy treated with VNS at Hospital Universitario de Alicante and Hospital Clínico de Valencia. Data were collected before and after the procedure. The difference in seizure frequency pre- and post-VNS was classified using the McHugh scale. Data were also collected on seizure duration and severity, the number of drugs administered, and quality of life. RESULTS: According to the McHugh classification, 12.86% of the patients were Class I, 44.29% were Class II, 40% were Class III, and the remaining 2.86% of patients were Class IV-V. A ≥ 50% reduction in seizure frequency was observed in 57.15% of patients. Improvements were observed in seizure duration in 88% of patients and in seizure severity in 68%; the number of drugs administered was reduced in 66% of patients, and 93% reported better quality of life. CONCLUSIONS: VNS is effective for reducing seizure frequency, duration, and severity and the number of antiepileptic drugs administered. It also enables an improvement in patients' quality of life.

The role of vagus nerve stimulation in the treatment of refractory epilepsy: Clinical outcomes and impact on quality of life. / Papel de la estimulación del nervio vago en el tratamiento de la epilepsia refractaria. Resultados clínicos e impacto en la calidad de vida.

BACKGROUND: Vagus nerve stimulation (VNS) is used as a complementary therapy to pharmacological treatment in patients with refractory epilepsy. This study aims to evaluate the efficacy of VNS in reducing seizure frequency, severity, and duration; reducing the number of antiepileptic drugs administered; and improving patients' quality of life. MATERIAL AND METHODS: We analysed the clinical progression of 70 patients with refractory epilepsy treated with VNS at Hospital Universitario de Alicante and Hospital Clínico de Valencia. Data were collected before and after the procedure. The difference in seizure frequency pre- and post-VNS was classified using the McHugh scale. Data were also collected on seizure duration and severity, the number of drugs administered, and quality of life. RESULTS: According to the McHugh classification, 12.86% of the patients were Class I, 44.29% were Class II, 40% were Class III, and the remaining 2.86% of patients were Class IV-V. A≥50% reduction in seizure frequency was observed in 57.15% of patients. Improvements were observed in seizure duration in 88% of patients and in seizure severity in 68%; the number of drugs administered was reduced in 66% of patients, and 93% reported better quality of life. CONCLUSIONS: VNS is effective for reducing seizure frequency, duration, and severity and the number of antiepileptic drugs administered. It also enables an improvement in patients' quality of life.

High-cervical spinal cord electrical stimulation in brain low perfusion syndromes: experimental basis and preliminary clinical report.

Previous studies of our group showed that C1-C2 spinal cord stimulation increases carotid and brain blood flow in normal conditions in the goat and dog and it has a beneficial vasomotor effect in a model of vasospasm in the rat. For further clinical application it seemed rational to investigate the possible vascular changes mediated by this technique in experimental brain infarction. To this aim, 45 New Zealand rabbits were used. Brain infarction was produced by bilateral carotid ligation in 15, unilateral microcoagulation of the middle cerebral artery in 15 and by microcoagulation of the vertebral artery at the craniocervical junction in the other 15. One week later, following daily clinical scoring and cortical and posterior fossa blood flow readings by laser Doppler, a period of 120 min of right C1-C2 spinal cord electric stimulation was performed. A mean of 27% increase in previous blood flow recordings was obtained at the right hemisphere and a mean of 32% in the posterior fossa. This procedure was used in 10 patients presenting with various cerebral low perfusion syndromes. Though not constant, an increase in alertness, retention, speech, emotional lability and performance in skilled acts was achieved. No MR changes were observed, though SPECT readings showed an increase in blood flow in the penumbral perilesional area.

Dorsal root entry zone lesion versus spinal cord stimulation in the management of pain from brachial plexus avulsion.

In six patients with total or partial brachial plexus avulsion, spinal cord stimulation was tried as pain treatment. Two patients had had amputation of the arm and suffered from phantom limb and stump pain. After a mean follow-up of 14 months two patients were painfree, one had partial relief and required analgesics and in three patients there was no effect. In eleven patients, including the three patients in whom spinal cord stimulation had failed to produce a long-lasting pain relief, dorsal root entry zone (DREZ) lesions were performed. At early follow-ups all these patients reported substantial pain relief, but after a mean follow-up of 17 months the results were less favorable: Three patients were pain-free, three had a marked improvement and five had recurrence of the original pain. Neither of the two methods of treatment produced any serious side-effects or permanent sequelae.

High-frequency cervical spinal cord stimulation in spasticity and motor disorders.

High frequency stimulation of the cervical spinal cord was used in an attempt to moderate motor disorders in 10 patients, 5 spastics, 3 dystonics and 2 with spasmodic torticollis. Through a C4 flavectomy a quadripolar flat electrode was introduced into the epidural space, placing the first terminal at C2. Electrical parameters for stimulation were established at 0.05-0.10 msec pulse width, rate of 200-1,400 Hz and amplitude to paresthesia threshold. Stimulation was delivered 1 hour on and 1 hour off during daytime. Subjective, clinical and/or neurophysiological initial improvement were initially observed in 9 cases, in which the stimulation system was permanently implanted. After a mean follow-up of 41.4 months all patients but one had a clinical and neurophysiological condition almost similar to the prestimulation one. To investigate the effect of the so-called high-frequency stimulation on the nervous system, 9 dogs were implanted following the same surgical technique and stimulated with analogous electrical parameters than in human practice. After follow-up of 8 months the pathological studies of the animals did not show any local or suprasegmental alterations on nervous structures except a local huge dural scarring reaction.

Spinal cord stimulation in peripheral arterial disease. A cooperative study.

Percutaneous epidural stimulation of the low thoracic spinal cord was carried out in 41 patients with pain from peripheral arterial disease of the lower limbs. Results are reported relating to pain, claudication distance, peripheral blood flow, and trophic lesion changes. Following a trial period of stimulation, 37 patients had stimulators permanently implanted. After a mean poststimulation follow-up period of 25 months, substantial pain relief (75% to 100%) was obtained in 29 cases; claudication distance significantly increased in 15 cases; Doppler ultrasound recordings of lower-limb distal arteries showed a tendency toward normalization of pulse-wave morphology, with increase of amplitude in 12 of the 23 patients studied; a rise in skin temperature was also detected by thermography. Distal arterial blood pressure remained unchanged with stimulation. Ischemic cutaneous trophic lesions of less than 3 sq cm healed, but gangrenous conditions were not benefited. A placebo effect or the natural history of the disease can be excluded as the reason for these improvements. It is concluded that spinal cord stimulation is a valid alternative treatment for moderate peripheral arterial disorders when direct arterial surgery is not possible or has been unsuccessful.

Influence of spinal cord stimulation on peripheral blood flow.

In 27 vasculopathic and 9 nonvasculopathic patients who underwent spinal cord stimulation to treat pain in lower extremities, Doppler recordings and thermography were used to study peripheral blood flow changes during stimulation. Generally, poststimulation pain relief coincided with a improvement of Doppler recording, a normalization of morphology and increase of pulse wave amplitude, and a rise of skin temperature in the painful area.