[Spinal electrical stimulation. Current indications and results in a series of 46 patients]. / Estimulación eléctrica medular. Indicaciones actuales y resultados en una serie de 46 pacientes.

We report the clinical results observed in a series of 46 patients with chronic pain who underwent spinal cord electrical stimulation. Candidates were selected according to previous clinical criteria and they were followed-up during a period of 5 to 27 months. Fifteen patients had a residual backache after surgery of the lumbar spine, 19 patients complained angina pectoris, 5 patients peripheral vasculopathies, and 7 subjects had different types of neurogenic pain. A total of 5 patients failed to complete the trial period of 7 to 10 days. Among the 34 patients who continued to use the medullar stimulation, good results were obtained in 75% of cases of backache , 100% of patients with angina and vasculopathies, and 50% of patients with neurogenic pain. There were no relevant complications. We conclude that the results of spinal cord stimulation can be improved by using more strict indications, by performing a previous test period before definitive implantation, and by achieving a large technical experience.

Intrathecal antiepileptic drugs in experimental epilepsy.

The effect of intrathecal administration of antiepileptic drugs on electroshock-induced convulsions (maximal electroshock seizure, MES test) was investigated in an experimental study in rats. Drugs tested were phenobarbital sodium (50-800 micrograms), sodium valproate (50-6,400 micrograms) and midazolam (50-250 micrograms), delivered into the cerebrospinal fluid via a catheter placed in the upper cervical intrathecal space. Control animals were tested with saline. The animals were tested in the MES test 30 min after drug administration. Phenobarbital sodium showed a dose-related protective effect on the tonic phase of the convulsion, with a 50% effect at a dose of 200 micrograms. Sodium valproate showed a less protective effect, even when reaching doses that produced neurological symptoms. Midazolam protected at a high dose but produced a severe decrease in motor activity. The results indicate the feasibility to treat experimental convulsions by means of intrathecal injection of antiepileptic drugs.

High cervical spinal cord stimulation for unstable angina pectoris.

Twelve patients with grade IV unstable angina were treated with high cervical spinal cord stimulation (SCS). All patients had been previously treated with maximal tolerated doses of beta-blockers and calcium antagonists and had no possibility of revascularization surgery or intraluminal angioplasty. Multipolar electrodes were implanted using a percutaneous technique, and the parameters of stimulation were pulse width 0.1 ms, frequency 120 Hz, intensity that caused no unpleasant paresthesias, with two periods of 4 h 'on' daily. After a mean follow-up of 9.8 +/- 8.2 months the clinical results show a significant reduction in the number of angina attacks (p less than 0.01) and in their grade (p less than 0.001). In the treadmill ergometric test, a significant increase in the time until angina and double product (p less than 0.01) was observed. We conclude that the SCS is a very low-risk technique that significantly increases the quality of life of patients with unstable angina.

[The quality of life of the patient with unstable angina treated by spinal cord electrical stimulation]. / Calidad de vida del paciente con angina inestable tratado con estimulación eléctrica medular.

Quality of life was evaluated in patients with unstable angina before and after surgical therapy with spinal cord electrical stimulation (SCES). Overall 12 patients were evaluated, with quantification of the mean weekly number of anginal attacks, the degree of effort provoking them and the Nottingham Health Profile (NHP). The criteria of inclusion in the study were: angina grade IV, resistant to drug therapy and without indication of surgery. The mean follow-up period was 9.8 +/- 8.2 months. A significant reduction in the weekly number of anginal attacks (preoperative 30.9 +/- 14.5; postoperative 9.6 +/- 8.2; p less than 0.01); improvement in functional class (p less than 0.001), and significant improvement (p greater than 0.05) in the pain, energy, sleep, social isolation and emotional reactions areas of NHP were observed. It was concluded that SCES is a useful procedure in patients with unstable angina untreatable by other medical or surgical methods, as it reduces the number of anginal attacks and increases quality of life of the patients without additional risk.