Ensayos clínicos

Cervical spinal cord stimulation (SCS) has been for many years hypothesized to be of use in treatment of cerebral vasospasm after subarachnoid hemorrhage. Experiments in animals and research in humans have demonstrated increase in cerebral blood flow (CBF), and different theories have been tried to explain these observations. Although there are many claims of circulatory improvements in these circumstances, no clinical application has yet been established. A complete understanding of physiological and anatomic correlation between CBF modulation and SCS remain unclear. We strongly believe that the main objective is not to treat vasospasm by increasing blood flow but to prevent vasoconstriction of the cerebral arteries by a functional sympathectomy. SCS may, at least theoretically, work in different ways at the same time: (1) preventing vasoconstriction of cerebral arteries by functional sympathectomy, acting at the lower cervical levels; and (2) increasing CBF through central pathways, perhaps involving brainstem connections, at the upper cervical levels. One of the practical implications of this hypothesis would be differential placement of cervical spinal cord stimulation electrodes in patients with subarachnoid hemorrhage depending on the timing of electrode insertion and presence or absence of vasospasm at the time of initial intervention. Read More on PubMed

Hosobuchi first studied the effect of spinal cord stimulation (SCS) on cerebral blood flow (CBF) in human beings along with the demonstration that SCS can improve peripheral blood flow. Following these clinical and experimental observations Hosobuchi first used cervical SCS for the treatment of cerebral ischemia in man. Further experimental reports suggested so far that SCS 1) drastically prevents cerebral infarction progression along with a reduction in infarct volume in cats; 2) improves clinical symptoms of patients in persistent vegetative states; 3) suppress headache attacks in migraneous patients; 4) significantly reduces ischemic brain oedema in rats; 5) increase locoregional blood flow in high grade brain tumors. The authors found that SCS can produce either an increase of CBF or a reduction or no effect. In patients studied with both SPECT technique and transcranial Doppler (TCD) the sign of the induced variations, when present in both, as the same. Cervical stimulation produces more frequently an increase in CBF (61% of cervical stimulations). The authors' experimental studies confirm that SCS 1) interacts with CO2 with the mechanism of regulation of CBF in a competitive way and produce a reversible functional sympathectomy; 2) produces similar flowmetric changes in the brain as well as in the eyes; 3) can improve both clinical and haemodynamic ischemic stroke in humans; 4) prevents hemodynamic deterioration in the experimental combined ischemic and traumatic brain injury; 5) prevents experimental early vasospasm. Read More on PubMed

We conducted a systematic review of the literature on the effectiveness of spinal cord stimulation (SCS) in relieving pain and improving functioning for patients with failed back surgery syndrome and complex regional pain syndrome (CRPS). We also reviewed SCS complications. Literature searches yielded 583 articles, of which seven met the inclusion criteria for the review of SCS effectiveness, and 15 others met the criteria only for the review of SCS complications. Two authors independently extracted data from each article, and then resolved discrepancies by discussion. We identified only one randomized trial, which found that physical therapy (PT) plus SCS, compared with PT alone, had a statistically significant but clinically modest effect at 6 and 12 months in relieving pain among patients with CRPS. Similarly, six other studies of much lower methodological quality suggest mild to moderate improvement in pain with SCS. Pain relief with SCS appears to decrease over time. The one randomized trial suggested no benefits of SCS in improving patient functioning. Although life-threatening complications with SCS are rare, other adverse events are frequent. On average, 34% of patients who received a stimulator had an adverse occurrence. We conclude with suggestions for methodologically stronger studies to provide more definitive data regarding the effectiveness of SCS in relieving pain and improving functioning, short- and long-term, among patients with chronic pain syndromes. Read More on PubMed

Transcranial Doppler (TCD) is used for diagnosis of vasospasm in patients with subarachnoid hemorrhage due to a ruptured aneurysm. Our aim was to evaluate both the accuracy of TCD compared with angiography and its usefulness as a screening method in this setting. Read More on PubMed

Cervical spinal cord stimulation (SCS) was used to increase cerebral blood flow (CBF) in 10 patients with secured cerebral aneurysms in Hunt and Hess grade 3 or 4 and with Fisher group 3 subarachnoid hemorrhage (SAH). The patients underwent preemptive electrical stimulation through a percutaneous lead following aneurysm surgery. All patients also received hypervolemic therapy and nicardipine. Efficacy of the treatment was evaluated using xenon computed tomography and cerebral angiography. The CBF in the distribution of the middle cerebral artery significantly increased following SCS (p < 0.05). Four of 10 patients showed angiographic vasospasm, but none developed severe sequelae of cerebral vasospasm. The overall outcome was good or excellent in seven of the 10 patients. No serious adverse effects due to SCS were observed. Fluid management and calcium antagonist have a beneficial effect on cerebral vasospasm following SAH, but is not tolerated or is ineffective in some patients. SCS as an adjunctive therapy for cerebral vasospasm following SAH may have a favorable effect on outcome. Read More on PubMed

We observed an increase in cerebral blood flow (CBF) for control of pain but were otherwise normal. Based on that observation, we implanted stimulators for cervical spinal cord stimulation (cSCS) in three patients who had symptomatic cerebral ischemia. Two had severe basivertebral occlusive disease and one had bilateral carotid occlusive disease. In all three cases, cSCS alleviated the symptoms of ischemia. Xenon-CBF studies or single-photon emission computer tomography (SPECT) showed increased CBF in response to cSCS. Although no mechanism clearly responsible for this remarkable therapeutic efficacy can be proposed yet, further clinical trials of cSCS for inoperable cerebral ischemia may be justified. Read More on PubMed

Ten patients were studied to determine the effect of spinal cord stimulation on CBF. In 5 patients using a cervical spinal cord stimulator, the stimulation produced a significant increase in CBF in the hemisphere ipsilateral to the induced paresthesia. Thoracic cord stimulation, used by the other 5 patients, had no effect on CBF. Atropine had no effect on the alteration in CBF produced by cervical cord stimulation. Indomethacin, however, partially blocked the effect. These heuristic observations may have implications for the future treatment of cerebrovascular insufficiency in humans. Read More on PubMed