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Biomedical subjects

M Visocchi

Publications and source records attributed to M Visocchi.

33 records · Page 2Linked to original sources

Spinal cord stimulation and cerebral blood flow: an experimental study.

Spinal cord stimulation (SCS) affects peripheral, coronary and cerebral blood flow (CBF) in humans. In 1986 Meglio et al. [Appl Neurophysiol 1986;49:139-146] advocated a functional reversible sympathectomy as one of the mechanisms of SCS in man. An experimental animal model was developed to study SCS effects on CBF and to investigate the possible mechanisms. Twenty-one white New Zealand rabbits were anesthetized with Fluothane; spontaneous ventilation was permitted. A steady hemodynamic and metabolic state was maintained. A small cervical laminectomy was performed and an electrode (Medtronic Sigma 3483) was placed in the epidural space over the posterior spinal cord. Both common carotid arteries were exposed and external carotid arteries were ligated. In 3 animals, the cervical symapthetic trunk (CST) was exposed and wrapped with bipolar hook-stimulating electrodes. SCS was performed for 20 min with electrical square waves of 210 microseconds duration, 80 cycles/s, at 2/3 motor threshold intensity. CST stimulation was delivered for 1 min with the following parameters: 10 V, 10 cycles/s, 0.5 ms duration. CBF velocities of both internal carotid arteries were measured by using a CW Doppler (in all the animals) and electromagnetic flowmeter (in 2 animals), at rest, during sympathetic trunk stimulation, during SCS, during simultaneous SCS and CST stimulation. During SCS, an increase of CBF was detected in 11 rabbits (52.4%); a decrease was observed in two cases (9.5%). No change was detected in the remaining 8 animals (38%). CST stimulation induced a decrease of CBF in all animals. Electromagnetic flowmetry confirmed velocitometric findings in the 2 cases studied.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Spinal cord stimulation in low back and leg pain.

We have reviewed our experience with spinal cord stimulation (SCS) in patients with low back and leg pain. 33 patients complaining of leg and low back pain underwent percutaneous tests of SCS. 28 patients had failed back surgery syndromes, 1 patient had pain related to an L1 vertebral body fracture, another from Tarlow cysts and the remaining 3 patients had lumbosacral spondyloarthrosis and osteoporosis without radiological signs of root compression. 28 patients showed mono- or pluriradicular deficits. At the end of the test period (5-65 days), 21 patients (63.6%) reported more than 50% of pain relief (mean analgesia 75%) and were submitted to chronic stimulation. The mean follow-up was 45.5 months. At maximum available follow-up, 40% of the patients (13 out of the 33 initial patients) were successfully using the stimulator (mean analgesia 66.6%).

Chronic Disease↗

Microvascular decompression for trigeminal neuralgia: prognostic factors.

A series of 66 patients with trigeminal neuralgia (TN) treated by microvascular decompression (MVD) is analyzed in order to define the importance of various prognostic factors. A typical pattern of pain, presence of facial hypaesthesia and previous ablative trigeminal procedures showed an unfavorable influence on the results of MVD. Duration of symptoms was longer in patients who failed to benefit from MVD. Pain distribution and the type of vascular compression did not influence the outcome.

Female↗

Intracerebral injury following thermocoagulation of the trigeminal ganglion.

An unusual postoperative complication of percutaneous thermocoagulation of the gasserian ganglion is reported. Computed tomography and magnetic resonance imaging of the brain disclosed an intracerebral lesion following the surgical procedure. Some rare abnormalities of the skull base could increase the risk of such complications. A meticulous surgical technique with fluoroscopic and neurophysiological control is mandatory in any percutaneous procedure on the trigeminal ganglion.

Brain Injuries↗

Spinal neurenteric cyst in association with syringomyelia: case report.

A case of spinal neurenteric cyst in association with Klippel-Feil deformity, spinal lipoma, and syringomyelia is presented. Neuroradiological evaluation was performed by means of magnetic resonance imaging of the spine and a computed tomography myelograph. The diagnosis of neurenteric cyst was established by histological and immunohistochemical studies. The pathogenesis of syringomyelia associated with an extramedullary mass lesion is discussed.

Adult↗

Antinociceptive activity of intracerebroventricular lysine acetylsalicylate: an experimental study.

We investigated the antinociceptive activity of Lysine Acetylsalicylate (LAS) after intracerebroventricular (icv) injection in experimental animals. The effect on tonic pain was studied by means of the Formalin test on 140 male Swiss mice. In a first group of animals icv LAS was injected at different doses (0.25-0.5-1 mg in saline solution 5 microliters). A second group received icv morphine 1 microgram in 5 microliters saline, and finally a third control group received icv 5 microliters saline. The effect of the compounds on the Formalin test was evaluated under blind conditions. Icv LAS had no effect on the nociceptive behaviour at doses of 0.25 and 0.5 mg, while a reduction of the licking time was evident after the injection of 1 mg of the drug. The time course and the degree of the analgesic effect of icv LAS was investigated and compared to the effect of icv morphine.

Analgesics↗

Spinal cord stimulation and cerebral haemodynamics.

An increase of regional cerebral blood flow (rCBF) has been shown to occur in man during spinal cord stimulation (SCS) by Hosobuchi (1986) and by Meglio et al. (1988) using the 133-Xenon wash-out technique. In this paper we report the effects of SCS on CBF as measured by two different techniques: 8 patients were studied with the 133-Xe method and 28 with the transcranial doppler sonography (TCD), in two cases both studies were performed. The aim of our study was to: 1-verify the effect of SCS on CBF, 2-compare observations made by two different methods, and 3-evaluate a possible correlation between the stimulated spinal segmental level and the modification of CBF. The results of our study confirm that SCS interacts with the mechanisms of regulation of CBF. The stimulation of different spinal cord levels in the same patient can produce different effects and such effects are reproducible. An increase of CBF is more likely to occur with the stimulation of the cervical spinal cord. In patients studied by both methods the sign of CBF changes induced by SCS was the same. Finally, in two patients the effect of SCS on CO2 autoregulation was studied with TCD. The results of such a study, although preliminary, suggest that CO2 and SCS have a competitive effect upon the mechanisms of regulation of CBF.

Blood Flow Velocity↗

Cerebral hemodynamics during spinal cord stimulation.

An increase of cerebral blood flow (CBF) during spinal cord stimulation (SCS) has been shown in man using the 133Xenon inhalation technique. We report the effects of SCS on cerebral hemodynamics studied with transcranial Doppler sonography (TCD). Twenty-six patients with epidural electrodes implanted at the cervical level (11 patients) and at the thoracic level (15 patients) were investigated with recordings of CBF velocity in the middle cerebral arteries before and during SCS. Sixty-three and two-thirds percent of patients with cervical stimulation and 29.4% of patients with thoracic stimulation showed a decrease of cerebral vascular resistance simultaneously with an increase of the velocity of CBF.

Blood Flow Velocity↗

Microvascular decompression versus percutaneous procedures for typical trigeminal neuralgia: personal experience.

This study includes 127 patients treated for typical trigeminal neuralgia, 74 of whom underwent a percutaneous microcompression (PMC), 33 a radiofrequency thermocoagulation (RFT) and 20 were explored for microvascular decompression (MVD). A mean follow-up of 24 months was reached by all the groups. Pain relief was evaluated as an 'all or none' effect. At hospital discharge, pain had disappeared in 93.2% of the patients treated with PMC, in 81.8% of those treated with RFT, and in 85% of the MVD group. At 24 months the effect was maintained by 57.2% of the PMC group, 57.6% of the RFT, and by 75% of the MVD group. Marked dysesthesia was reported by 6.7% of the patients treated with PMC, and by 24.2% of those who received a RFT. Impairment of masticatory function was observed in 10% of the PMC patients. Ipsilateral hypoacusia and transient IV nerve palsy in 1 patient was the only major complication after MVD.

Electrocoagulation↗

[Diffuse axonal lesions in childhood].

OBJECTIVE: About 48% of all primary traumatic intracranial lesions are represented by so-called Diffuse Axonal Injury (DAI): a pathologic condition characterized by multiple microscopic lesions and hemorrhage at the level of midline cerebral structures, in the subcortical grey matter, and/or within the brainstem. The natural history of DAI is depressing: 100% of the patients deteriorate rapidly to coma and approximately 50% die, while 50% remain in a vegetative state or with severe neurological deficits. In the present report, we describe the results of a study aimed to evaluating the cerebral hemodynamics and the neuroradiological findings observed in four children (6, 8, 10 and 12 years old) affected by DAI. METHODS: All the patients had been admitted to the Pediatric Intensive Care Unit with Glasgow Coma Score (GCS) of 5. On admission, all patients underwent mechanical ventilation, antiedemigen and barbiturates therapy. Serial CT scan and Transcranial Doppler Sonography (TCD) examinations were carried out in all children. TCD of the middle cerebral arteries was performed through the temporal window. The children underwent insertion of a ventricular catheter for intracranial pressure monitoring. Follow-up time has been, respectively, 4 years, 3 years, 7 and 1 months. RESULTS: The Glasgow Outcome Score (GOS) of three children is 2 (persistent vegetative state), while the GOS of the one child is 3 (severe neurological deficits). CONCLUSION: DAI results in unfortunate prognosis and large health care costs. The proper medical management of this condition should be based on TCD and SjO2 and CEO2 evaluations, in order to monitor efficaciously the cerebral blood flow.

Adolescent↗

[Cerebral vasospasm and intracranial hypertension: transcranial Doppler ultrasonographic findings].

Four consecutive patients with subarachnoid hemorrhage were studied by serial cranial CT and transcranial Doppler ultrasonographic recordings. Patients were in the age range 52 to 67 years. According to Hunt and Hess scale the clinical status varied between grade I and IV. Increase in intracranial pressure "masked" the hemodynamic signs of cerebral vasospasm, reappeared after normalization of intracranial pressure following therapeutic management. Based on the reported findings transcranial Doppler ultrasonography should be considered an indispensabile diagnostic procedure however inadequate for monitoring the natural history of vasospasm complicated by intracranial hypertension.

Aged↗

[Transcranial Doppler sonography in neurotraumatology: hemodynamic monitoring of diffuse axonal injury].

Six patients with diffuse axonal injury, ranging in age 8 to 29 years, hospitalized in emergency in our Polyclinic with a Glagow coma score under 8, were examined. Patients were intubated and connected to an automatic respirator. They underwent serial cranial CT and transcranial Doppler sonography recordings using the temporal window with insonation of the two middle cerebral arteries. During the period of observation, the metabolic processes and systemic hemodynamics were maintained within the limits of homeostasis. In all cases and at different times, osmotic diuretics (18% mannitol), barbiturates and hyperventilation therapy were administered. In 5 patients over 6 (80%) increased blood flow, variously sensitive to barbiturates, was detected associated to increased resistance index secondary to intracranial hypertension. Based on Doppler findings four patients underwent surgical treatment: ventriculostomy for monitoring of intracranial pressure or decompressive craniectomy. According to this experience, the use of transcranial Doppler US is mandatory for a correct identification of the hemodynamic injury associated to diffuse axonal injury, for planning the medical and/or surgical approach and for assessment of the successful results of therapeutic management.

Adult↗