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Biomedical subjects

M Visocchi

Publications and source records attributed to M Visocchi.

At least 19 recordsLinked to original sources
PubMed2006

A new animal model for monitoring the early cerebral vasospasm after subarachnoid haemorrhage.

AIM: Spasm of cerebral arteries is a complication associated with subarachnoid haemorrhage. The aim of the present work is to find an experimental model of reliable, simple and in vivo monitoring of ''early'' basilar artery spasm after subarachnoid haemorrhage (SAH). Early spasm occurs within minutes of the SAH, its duration is approximately 1 hour. The need of different morphological and haemodynamic methods to evaluate experimental early spasm is reported. METHODS: To overcome intracranial surgical manipulations and biological of contrast and fixation media we designed a model that allows in vivo functional monitoring of basilar blood flow far away from the spasm without direct surgical and chemical interferences. Seventeen adult Burgundy rabbits were studied. RESULTS: Under homeostatic monitoring ''on-line'' carotid blood flow (carotid BF) .changes produced by SAH in cisterna magna of 12 (plus 5 sham treated) animals were studied from the common carotid artery after external carotid artery occlusion before, during SAH up to the end of the experiments. All the animals underwent digital subtraction cerebral panangiography (CPA) after SAH obtaining a significant increase of carotid BF only when basilar vasospasm was shown by CPA. CONCLUSIONS: Carotid BF increase during basilar vasospasm was defined ''functional. monitoring'' of early spasm.

Angiography↗
PubMed2003

Craniocervical junction instability: instrumentation and fusion with titanium rods and sublaminar wires. Effectiveness and failures in personal experience.

BACKGROUND: The aim of the study was to evaluate the effectiveness, pitfalls and failures of instrumentation and fusion with titanium wires and rods in 12 h patients with craniovertebral junction instability. METHODS: Among nine adult patients (mean age 48.11 years) with craniovertebral junction instability, four had basilar impression, three metastatic disease, one rheumatoid arthritis and one Down's syndrome. Three children (mean age 7.33 years) with genetic (Down's syndrome, 2 cases) and metabolic (mucopolisaccarydoses type IV, i.e. Morquio Syndrome, 1 case) disease were studied as well. Each patient underwent preoperative radiological evaluation by means of X-Ray, CT scan and MRI of the craniocervical region. Occipitocervical instrumentation with a titanium U-shaped wired rod was performed in each patient. Autologous bone fusion was performed in all but the two cancer patients, in whom polymethylmetacrylate was used. Postoperatively, all the patients used an external orthosis for 3-6 months. Post-operative X-Ray, CT and MRI were performed on each patient. The Frankel clinical scale was used to asses the outcome at follow-up which ranged from 1 to 10 years. At maximum follow up, there was either clinical improvement or stabilization recorded in all but one patient. This patient with basilar impression transiently worsened from grade D to C and a spinal cord lesion was already evident before the operation on MRI examination. INTERPRETATION: The effectiveness of surgical management of craniovertebral junction instability by instrumentation and fusion was demonstratedly in our experience. Nevertheless, the choice of the surgical technique should be made with caution when a spinal cord lesion is revealed by preoperative neuroimaging studies.

Adult↗
PubMed2003

Subacute clinical onset of postraumatic myelopathy.

BACKGROUND: Subacute neurological deterioration unrelated to mechanical instability is a rare event. CASES REPORT: The authors describe two patients with subacute neurological deterioration unrelated to mechanical instability, which occurred 24 hours after spinal cord injury.The phenomenon could not be prevented by steroid therapy carried out either before or after the onset of clinical signs. An early surgical decompressive procedure performed in one of the two patients, failed to reverse the clinical symptomatology. FINDINGS: In the first case, temporal evolution of the neurological deterioration suggested a venous thrombosis with secondary congestive ischemia, whereas ischemia involving the anterior spinal artery seems to account for the deterioration observed in the second patient. INTERPRETATION: Spinal cord haemodynamics plays the main role in mediating the onset of descending subacute posttraumatic myelopathy. The cure and the prevention of the secondary vascular injury still remains unknown.

Acute Disease↗
PubMed2002

Direct demonstration of long latency cortico-cortical inhibition in normal subjects and in a patient with vascular parkinsonism.

OBJECTIVE: The motor evoked potential to a single suprathreshold transcranial magnetic stimulus (TMS) is suppressed by a preceding stimulus given 100-200 ms before (long latency intracortical inhibition, LICI). The effect is enhanced in patients with Parkinson's disease. Although previous studies have agreed that the effect is cortical, there is disagreement over exactly which cortical mechanisms are involved. The aim of this study was to provide further evidence for cortical involvement in LICI. METHODS: Recordings of corticospinal volleys evoked by the TMS stimulation were made from electrodes inserted into the cervical epidural space of 4 conscious subjects. Three of the patients had received the electrodes for treatment of lumbo-sacral pain; the other patient had vascular parkinsonism, and had the electrode implanted to evaluate its effect on cerebral blood flow. The number and amplitude of the volleys were compared with and without a conditioning stimulus. RESULTS: In 3 pain patients, a conditioning stimulus suppressed the later components of the corticospinal volley (I2 and later waves) when the interval between stimuli was 100-150 ms; at 50 ms the responses were enhanced. Early components of the volley were not affected. Inhibition was much more pronounced and involved all descending volleys except the D wave in the patient with vascular parkinsonism. CONCLUSIONS: LICI, which is conventionally described in EMG recordings, is also evident in recordings of descending corticospinal volleys and appears enhanced in a patient with vascular parkinsonism.

Back Pain↗
PubMed2002

Hypoflow and hyperflow in diffuse axonal injury. Prognostic and therapeutic implications of transcranial Doppler sonography evaluation.

BACKGROUND: In the present report we describe the results of a study aimed at evaluating the cerebral haemodynamics and the neuroradiological findings observ-ed in 7 consecutive patients, 4 adults and 3 children (6, 8 and 10 years old), affected by diffuse axonal injury (DAI). METHODS: All the patients were admitted to the Paediatric or Adult Intensive Care Unit with GCS scores less than 8 after a severe brain injury. Serial head CT scan and trans-cranial Doppler sonography (TCD) examinations were carried out in all patients; MRI was carried out in the paediatric patients only. TCD of the middle cerebral arteries was performed through the temporal bone window. In 6 cases (2 paediatric) diuretic osmotic therapy was immediately administered and in 6 cases (3 paediatric) barbiturates and hyperventilation were also used. RESULTS: Hyperflow, variably responsive to barbiturate therapy of vasoparalysis, was observed in all paediatric patients and in 3 adult subjects (85.7%: 6 out of 7 pa-tients) by means of TCD. CONCLUSIONS: Observation of these phenomena allowed us to modify the pharmacological treatment and/or perform external cerebrospinal fluid (CSF) drainage (4 cases). Compartimental hyperflow TCD pattern was evident in 1 patient. Although the limited number of patients in our series does not allow definitive conclusions, we strongly believe that TCD monitoring is an useful tool in planning surgical strategy in patients with DAI.

Accidents, Traffic↗
PubMed2001

Spinal cord stimulation and early experimental cerebral spasm: the "functional monitoring" and the "preventing effect".

BACKGROUND: Clinical and experimental data on cerebral blood flow (CBF) changes during spinal cord stimulation (SCS) were published since 1986. The aims of the present work are: 1. To find an experimental model of reliable, simple and in vivo monitoring of "early" basilar artery spasm after subarachnoid haemorrhage (SAH) and 2. To investigate the effects of cervical spinal cord stimulation (CSCS) on it. Vasospasm due to SAH is both "acute" and "recurrent". Early spasm occurs within minutes of the SAH. its duration is approximately 1 hour. The need of different morphological and haemodynamic methods to evaluate experimental early spasm is reported. To overcome intracranial surgical manipulations and biological effects of contrast and fixation media we designed a model that allows "in vivo" functional monitoring of basilar blood flow far away from the spasm without direct surgical and chemical interference. Subsequently we investigated the effects of CSCS on the new model of "functional monitoring" of the "early" cerebral vasospasm. METHOD: 29 adult Burgundy rabbits were studied. Group 1: under homeostatic monitoring, "on-line" carotid blood flow (carotid BF) changes produced by SAH in cisterna magna of 12 (plus 5 sham treated) animals were studied from the common carotid artery after external carotid artery occlusion before, during SAH and up to the end of the experiments. All the animals underwent digital subtraction cerebral panangiography (CPA) after SAH obtaining a significant increase of carotid BF only when basilar vasospasm was shown by CPA. Carotid BF increase during basilar vasospasm was defined "functional monitoring" of early spasm. Group 2: Twelve animals wearing a cervical epidural electrode underwent carotid BF "functional monitoring" of early basilar spasm before and during CSCS. FINDINGS: Carotid BF changes during CSCS occurred in 10 animals. No carotid BF changes (i.e. no basilar vasospasm) occurred after SAH up to the end of the experiments in all the stimulated animals. INTERPRETATION: CSCS is able to prevent "early spasm" due to SAH in all the animals studied with the new model of "functional monitoring" described, independently from the occurence and the sign for stimulation-induced carotid BF variations. The role and the limits of reversible functional sympathectomy in mediating the effect of CSCS on early vasospam are discussed.

Acute Disease↗
PubMed2001

Spinal cord stimulation and cerebral blood flow in stroke: personal experience.

Spinal cord stimulation (SCS) can increase cerebral blood flow (CBF) and improve stroke patients. In order to better understand the haemodynamic changes underlining the clinical improvement, we have studied with transcranial Doppler (TCD), SPECT and NIRS 18 patients harbouring a stroke. SPECT Group: An increase of regional CBF during SCS was measured far from the stroke areas in 9 patients, further decrease in CBF was found in 2, no changes in 1. TCD Group: An increase of CBF velocities during SCS was found in 4 patients, no changes in 6, a decrease in 1. NIRS Group: Data consistent with and increase in CBF were obtained during SCS in the only patient undergone such a study. In 6 patients studied with different techniques, data obtained fitted only in 2 patients. In 3 patients no changes in TCD faced with changes in SPECT. In one case an improvement in TCD was evident in the left while an improvement of SPECT was shown in the right site. SCS is a valid therapeutic tool in stroke patient even if, as matter of fact, parallelism between clinical and haemodynamic changes during SCS is not demonstrated in our patients, rising the question on the role of ischemic penumbra in mediating clinical improvement.

Adult↗
PubMed2001

Protective effect of spinal cord stimulation on experimental early cerebral vasospasm. Conclusive results.

In this study we investigate the effects of cervical spinal cord stimulation (cSCS) on experimental 'early spasm' in rabbits as described in personal previous experience (Acta Neurochir 2001;143:177-185). Twenty-four adult red Burgundy rabbits wearing a cervical epidural electrode underwent cerebral blood flow (CBF) and functional monitoring of early basilar spasm before and during cSCS. CBF changes, as a consequence of cSCS, occurred in 20 control animals. No CBF changes, consistent with no basilar artery vasospasm, occurred after subarachnoid haemorrhage (SAH) up to the end of the experiments in all the stimulated animals. The role of reversible functional sympathectomy in mediating the effect of spinal cord stimulation on early spasm is discussed. cSCS is able to prevent 'early spasm' due to SAH in all the animals studied, independently from the occurrence and the sign of stimulation induced CBF variations.

Animals↗
PubMed2001

Spinal cord stimulation prevents the effects of combined experimental ischemic and traumatic brain injury. An MR study.

Spinal cord stimulation (SCS) interferes with cerebral blood flow (CBF). In this paper we try to evaluate the possible preventing effect of SCS in an animal model of combined ischemic and traumatic injury. We studied 20 New Zealand rabbits undergoing ligature of both carotid arteries and a right hemispheric craniectomy and about 3 h mechanical injury (200 mg) over the dura. In 10 animals (control group) SCS was not delivered; in 10 (SCS group) cervical SCS was started 20 min after arterial ligation and before the craniectomy and the mechanical injury. MR examination was performed in all the animals at the end of the experiments. Compared to the control group none but one of the SCS showed lesional pattern far from the craniectomy suggesting a 'preventing' effect of SCS on the secondary damage associated with our model combined ischemic and traumatic brain injury.

Animals↗
PubMed1999

Inconsistent MRI findings in acute pre-Willisian brain ischemia in rabbit: a useful model?

BACKGROUND: We have investigated a model of "preterminal ischemia" in order A) to assess the MRI findings and the repeatability of the anatomical changes as showed by MRI, and B) to compare the data so obtained with the humans. METHODS: Twenty rabbits were used. Under general anesthesia, the occlusion of 1) the two common carotid arteries (from 2 hours up to 24 hours) was performed in 8 cases, and of 2) the epi-aortic vessels at the aortic arch (from 2 hours up to 4 hours) was performed in 4 cases in general anesthesia. RESULTS: In the vessels occlusion group MRI study showed inconsistent, inconstant, predominantly ill defined, linear and/or spotlike hyperintense deep cerebral alterations, variable in location, unilateral and bilateral in 8 cases. Although in carotid occlusion the damage was already evident within the first two hours, aortic arch occlusion was unable to produce global brain lesional pattern even up to 4 hours. MRI study of the sham operated animals was negative. CONCLUSIONS: The selective vulnerability of mesial deep cerebral structures to hypoxia, different in location from the human's, and the more effective pre-Willisian compensation, suggests to look for different animals when dealing with preterminal ischemic models comparable to the humans' as studied with MRI.

Animals↗
PubMed1998

Thoracoscopic approaches to the thoracic spine.

Microsurgical approaches for the treatment of pathology located in the ventral thoracic spine using video-assisted thoracic surgery (VATS) allow neurosurgeons to access the disc spaces, vertebral bodies, paravertebral soft tissues, spinal cord, spinal nerves, and sympathetic chain with minimally invasive surgery. This has been associated with substantial clinical benefits including reduced postoperative pain, lower complication rates and shorter recovery times when compared with standard thoracotomy techniques. This article describes the experience at our institution with VATS for discectomy (20 cases), corpectomy and spinal reconstruction (8 cases), thoracic sympathectomy (3 cases), and nerve sheath tumor removal (1 case). The technique can be mastered but requires surgeons to learn the new psychomotor skills needed to perform endoscopic spine surgery. The learning curve is steep. Special training in instructional seminars, surgical skill laboratories, and clinical preceptorships is needed before this surgical approach can be used clinically to treat spinal pathology. VATS has significant advantages compared to standard thoracotomy, including reduced incisional pain and avoidance of the postthoracotomy pain syndrome. If intercostal neuralgia develops postoperatively, it is milder and usually transient compared to the pain associated with standard thoracotomy. Better cosmetic outcomes, earlier mobilization, and faster recovery are added benefits. The surgical techniques are relatively new for neurosurgeons and require dedicated practice to master them. Once the surgical skills are perfected, VATS is feasible for spinal pathology and can be performed safely and effectively.

Adolescent↗
PubMed1997

Cervical cord compression due to atypical primary neuroectodermal tumor (PNET): one-stage removal and combined cervical spine stabilization. Case report.

INTRODUCTION: The neuroectodermal tumor of bone constitutes a recently isolated neoplasm, which morphologically resembles the peripheral neuroepithelioma of soft tissue. The diagnosis is made by excluding readily classified small round cell neoplasms and then demonstrating the neural origin of the tumor by means of ultrastructural or immunocytochemical studies. CLINICAL CASE: We report a case of a primary neuroectodermal tumor (PNET) with atypical findings (primary cervical location, massive vertebral body infiltration and isolated neurological symptomatology). Total tumor removal was achieved by means of a one-stage three-level laminectomy (partial C5, total C6-C7), C6 somatectomy, and combined anterior and posterior cervical spinal instrumentation and fusion. CONCLUSIONS: Our case presents three peculiar features: 1) isolated myelopathic symptomatology (first case described); 2) primary isolated massive vertebral cervical involvement with intraspinal epidural extension (first case described); 3) one-stage tumor resection, fusion and instrumentation. Since radiation therapy causes tumor shrinkage but is not curative, radical removal is mandatory even with complex instrumentation procedures.

Cervical Vertebrae↗
PubMed1996

Cerebral blood flow velocities and trigeminal ganglion stimulation. A transcranial Doppler study.

Transcranial Doppler sonography (TCD) patterns of middle cerebral arteries (MCA) were recorded in 10 patients before and during unilateral trigeminal ganglion stimulation (TGS). During TGS, TCD flow velocity significantly decreases in all patients: on both sides in 2 patients, only ipsilaterally to the TGS in 7 patients, and only on the opposite side in the remaining patient. In 2 patients, a controlled progressive hypercapnia test was performed before and during TGS. An enhanced vascular response to increased CO2 concentrations was observed during TGS.

Blood Flow Velocity↗
PubMed1996

[Tetanus: problems of differential diagnosis in the presence of contemporaneous administration of metoclopramide].

Here we report a clinical case concerning differential diagnosis between tetanus and metoclopramide intoxication. A 67 year old woman was admitted to our intensive care unit complaining of both trisma and four limbs hypertone soon after a massive metoclopramide bolus administration. The patient was affected by a chronicle renal insufficiency and a diagnosis of metoclopramide intoxication was made. The long lasting dystonic symptomatology together with respiratory insufficiency ruled out the hypothesis of drug overdose. The intensive care physicians would take into account that at least a 24 hours clinical observation is mandatory in order to perform a correct diagnosis.

Aged↗
PubMed1995

"Filtering effect" of cerebrospinal fluid on spinal somatosensory evoked potentials: case report.

A 31-year-old man presented complaining of radicular (L4) pain. MRI and myelo-TC of the thoraco-lumbar spine showed the presence of an extradural CSF cyst extending from Th6 to L2, posterior to the cord. The patient underwent a Th12 laminectomy, the cyst was opened and drained. A recording electrode was placed epidurally, dorsal to the cyst, at the level of the Th12 vertebral body, and the potentials evoked by stimulation of the tibial and saphenous nerves were monitored during surgery. After cyst drainage the epidural potentials were significantly larger (x5) in amplitude and more defined in shape than those recorded in the presence of the cyst. Our case demonstrates the "filtering effect" of CSF on spinal somatosensory evoked potentials.

Adult↗
PubMed1995

Spinal cord stimulation in the treatment of paraplegic pain.

Twenty-five patients suffering from intractable pain due to a chronic spinal cord lesion underwent a percutaneous test of spinal cord stimulation. At the end of the test period, 40.9% of the patients reported a mean of 65% pain relief and these patients were selected for ongoing stimulation. At a mean follow-up time of 37.2 months the success rate, based on the number of patients with more than 50% pain relief, had fallen to 18.2%. Pain relief rates were analyzed in relation to quality of pain, neurological status, level and extent of the lesion, and electrode level to identify prognostic factors that could improve the clinical usefulness of spinal cord stimulation. Patients experiencing painful spasms or a constrictive type of pain and with incomplete thoracic lesions were found to be the best candidates for spinal cord stimulation.

Adult↗
PubMed1994

Increase of cerebral blood flow and improvement of brain motor control following spinal cord stimulation in ischemic spastic hemiparesis.

A 64-year-old man had an ischemic stroke in the left parietotemporal cortical-subcortical areas. He developed a severe right spastic hemiparesis and dysphasia. An angiographic study showed left internal carotid artery occlusion and right internal carotid artery stenosis. A right internal endoarteriectomy was performed without any clinical improvement. After 1 year the patient was a candidate for cervical spinal cord stimulation (SCS) for the treatment of his spastic hemiparesis. An epidural electrode (Medtronic Sigma 3483) was positioned at the cervical level, mediodorsal to the cord. Clinical and neurophysiological studies (surface polyelectromyography, PEMG, for evaluation of brain motor control) were performed before and after 7 days of SCS (0.2 ms, 80 c/s, intensity for paresthesiae, continuous mode). A transcranial Doppler (TCD) study of both middle cerebral arteries (MCA) at rest and during SCS was performed on two occasions. SCS was followed by improvement of voluntary movement, decrease of spasticity and better endurance. The clinical findings were confirmed by the PEMG recordings. TCD examination showed an increase of flow velocities on both the right MCA (+43%) and the left MCA (+130%) during SCS. Such a TCD pattern, suggesting an increase of cerebral blood flow (CBF) during SCS, was reproducible. This case confirms efficacy of SCS in the treatment of ischemic hemiparesis and the increase of CBF following cervical SCS in man. The marked increase of CBF, particularly evident on the ischemic side, may play a role in mediating the improvement of motor control in our patient together with a possible arousal of the so-called 'sleeping neurons' of the penumbra zone.

Brain Ischemia↗