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D G Iacopino

Publications and source records attributed to D G Iacopino.

13 recordsLinked to original sources
PubMed2006

Cerebral haemodynamic changes during propofol-remifentanil or sevoflurane anaesthesia: transcranial Doppler study under bispectral index monitoring.

BACKGROUND: Sevoflurane or propofol-remifentanil-based anaesthetic regimens represent modern techniques for neurosurgical anaesthesia. Nevertheless, there are potential differences related to their activity on the cerebrovascular system. The magnitude of such difference is not completely known. METHODS: In total 40 patients, treated for spinal or maxillo-facial disorders, were randomly allocated to either i.v. propofol-remifentanil or inhalational sevoflurane anaesthesia. Transcranial Doppler was used to assess changes in cerebral blood flow velocity, carbon dioxide reactivity, cerebral autoregulation and the bispectral index to assess the depth of anaesthesia. RESULTS: Time-averaged mean flow velocity (MFV) was significantly reduced after induction of anaesthesia in both sevoflurane and propofol-remifentanil groups (P<0.001). At deeper levels of anaesthesia, MFV increased in the sevoflurane group, suggesting an uncoupling flow/metabolism, whereas it was further reduced in the propofol-remifentanil group (P<0.001). Indices of cerebral autoregulation were reduced in patients with high-dose sevoflurane whereas autoregulation was preserved in patients anaesthetized with propofol-remifentanil (P<0.001). Higher CO(2) concentrations impaired cerebral autoregulation in the sevoflurane group but not in patients anaesthetized with propofol-remifentanil. CONCLUSIONS: Propofol-remifentanil anaesthesia induced a dose-dependent low-flow state with preserved cerebral autoregulation, whereas sevoflurane at high doses provided a certain degree of luxury perfusion.

Adult↗
PubMed2003

Assistance of intraoperative microvascular Doppler in the surgical obliteration of spinal dural arteriovenous fistula: cases description and technical considerations.

BACKGROUND: Intraoperative microvascular Doppler may be valuable in assisting in the surgical obliteration of dural arteriovenous fistula of the spinal cord. It enables identification, through flow spectrum analysis, of the anatomic components and haemodynamic features of this type of vascular malformation. METHODS: In two cases, intraoperative microvascular Doppler was used to assist in the surgical obliteration of dural arteriovenous fistula of the spinal cord. The fistulas were identified prior to the dura opening, and for this only minimally invasive surgery was required. Direct recordings of the arterialised draining vein and the nidus of the fistula demonstrated a pathological spectrum caused by the arterial supply and the disturbed venous outflow in which a high-resistance flow pattern and low diastolic flow resembling an arterial-like flow velocity were observed. FINDINGS: The fistulas were obliterated by interruption of the draining vein, and Doppler measurements provided information on flow velocity changes in the medullary veins from an arterial to a venous pattern. The absence of any residual flow in the draining vein confirmed successful haemodynamic treatment. INTERPRETATION: Intraoperative microvascular Doppler recording is valuable assistance in surgical closure of spinal arteriovenous fistula.

Aged↗
PubMed2003

Different methods for anatomical targeting.

AIM: Several procedures are used in the different neurosurgical centers in order to perform stereotactic surgery for movement disorders. At the moment no procedure can really be considered superior to the other. We contribute with our experience of targeting method. METHODS: Ten patients were selected, in accordance to the guidelines for the treatment of Parkinson disease, and operated by several methods including pallidotomy, bilateral insertion of chronic deep brain electrodes within the internal pallidum and in the subthalamic nucleus (18 procedures). INTERVENTIONS: in each patient an MR scan was performed the day before surgery. Scans were performed axially parallel to the intercommissural line. The operating day a contrast CT scan was performed under stereotactic conditions. MEASURES: after digitalization of the MRI images, it was possible to visualize the surgical target and to relate it to parenchimal and vascular anatomic structures readable at the CT examination. The CT scan obtained was confronted with the MR previously performed, the geometrical relation between the different parenchimal and vascular structures and the selected targets were obtained. Stereotactic coordinates were obtained on the CT examination. RESULTS: It was possible to calculate the position of the subthalamic nucleus and of the internal pallidum on the CT scan, not only relating to the intercommissural line, but considering also the neurovascular structures displayed both on the MRI and the CT scans. CONCLUSION: The technique that our group presents consist in an integration between information derived from the CT and the MR techniques, so that we can benefit from the advantages of both methods and overcome the disadvantages.

Aged↗
PubMed2001

Intraoperative microvascular Doppler monitoring of blood flow within a spinal dural arteriovenous fistula: a precious surgical tool. Case report.

The authors describe a case of spinal arteriovenous fistula (AVF) treated by a microvascular Doppler-assisted surgical interruption of the arterialized vein. Microvascular Doppler monitoring represents a valid, widely available, noninvasive tool that enables identification, through flow spectrum analysis, of components of this type of vascular malformation. In this case because the location of the fistula was identified prior to opening the dura only minimally invasive surgery was required. Direct recordings of the arterialized draining vein and the nidus of the fistula demonstrated a pathological spectrum caused by the arterial supply and the disturbed venous outflow in which a high-resistance flow pattern and low diastolic flow resembling an arterial-like flow velocity were observed. The fistula was obliterated by interruption of the draining vein, and Doppler measurements provided information on flow velocity changes in the medullary veins from an arterial to a venous pattern. The absence of any residual flow in the AVF confirmed successful hemodynamic treatment. Intraoperative microvascular Doppler recording during surgical closure of spinal AVF is a widely available and reliable monitoring modality that helps to produce excellent clinical results.

Central Nervous System Vascular Malformations↗
PubMed1997

Use of middle cerebral velocity and blood pressure for the analysis of cerebral autoregulation at various frequencies: the coherence index.

A common component in many protocols for the evaluation of cerebral autoregulation is the comparison of transcranial Doppler ultrasound (TCD) velocities with blood pressure recordings, in which correlations between these two signals correspond to impaired autoregulation. With long data sets and complicated paradigms, however, visual inspection alone cannot adequately distinguish random coincidence from consistent correlation in a statistically valid fashion. We suggest and illustrate the use of the coherence index for this purpose. To illustrate this technique, long-term recordings of TCD velocity and blood pressure were obtained from 6 normal subjects and using 23 data segments from 8 patients following subarachnoid hemorrhage. Each signal was first normalized to its mean, and coherence calculated by dividing the data into overlapping subintervals and computing an average. Coherence was specifically examined over time periods of 30 sec. Coherence calculations identified correlations between signals for which interpretation by visual inspection was unclear, and obvious correlations could be quantified. In 4 of the 6 normal subjects, the coherence was less than 0.60 but slightly greater than 0. Five of the 8 patients showed segments with coherence of greater than 0.60. The coherence index provides a quantitative tool for the evaluation of comparisons between two complex signals. As this task becomes more common in the evaluation of cerebral autoregulation, algorithms of this sort will become increasingly necessary.

Blood Flow Velocity↗
PubMed1997

Do spinal meningiomas penetrate the pial layer? Correlation between magnetic resonance imaging and microsurgical findings and intracranial tumor interfaces.

OBJECTIVE: To study the relationships between spinal dura-arachnoid and tumor-cord interfaces in spinal meningiomas and to investigate whether a disruption of the pial layer and penetration of the tumor in the spinal cord occurs. METHODS: Fifteen patients with histologically proven meningiomas underwent magnetic resonance imaging (MRI) preoperatively. All patients underwent microsurgery. The histological characteristics of the tumors were compared with MRI and microsurgical findings. RESULTS: At surgery, the peritumoral hypointense rim revealed by MRI in 10 of 15 patients corresponded to a well-defined cerebrospinal fluid-containing space confined between the outer arachnoidal layer and the inner leptomeningeal layer. In those patients in whom the hypointense peritumoral rim was absent, the inner layer was either difficult to identify or clearly absent, and the blood vessels were extremely adherent to the tumor, requiring a more cautious dissection. Penetration of the tumors through disruption of the pial surface was not documented. CONCLUSION: Previous anatomic and electron microscopy studies demonstrated, in human spinal meninges, the presence of an intermediate layer attached to the inner aspect of the arachnoid, extending laterally over the dorsal surface of the spinal cord and arborizing over the nerve roots and blood vessels. The intermediate layer is not present in human cerebral leptomeninges. The presence/absence of this layer might explain the hypointense rim detected by MRI and might also explain why no penetration and no peritumoral edema is observed in spinal meningiomas as compared with intracranial meningiomas.

Adult↗
PubMed1996

Cervical neuroma presenting as a subarachnoid hemorrhage: case report.

OBJECTIVE AND IMPORTANCE: The association of subarachnoid hemorrhage (SAH) with spinal lesions is well known, but hemorrhage from a cervical schwannoma is exceedingly rare. The histopathology and the mechanism of bleeding are discussed. CLINICAL PRESENTATION: We report a healthy 37-year-old man presenting with SAH after intense physical stress caused by bleeding of a cervical neuroma. INTERVENTION: A C6-T1 laminectomy disclosed an ovoid lesion, 4 cm in diameter; extremely dilated veins originated from the tumor. Removal of the spinal lesion resulted in immediate decongestion of the related venous network. The histopathological examination confirmed that the lesion was a telangiectatic schwannoma. The mechanism of bleeding of the intraforaminal cervical schwannoma is discussed. CONCLUSION: Telangiectatic neuromas may be a cause of occult SAH. The importance of magnetic resonance imaging of the cervical spine is emphasized to explain SAH with negative findings on four-vessel angiography in patients whose SAH may have a surgically correctable cause distant from the intracranial compartment.

Adult↗
PubMed1995

Intraoperative monitoring of cerebral blood flow during ventricular shunting in hydrocephalic pediatric patients.

Several studies have demonstrated lowered cerebral blood flow (CBF) in patients with hydrocephalus and symptoms of raised intracranial pressure. Ventricular shunting in such cases permits a sudden increase in CBF. The pathophysiology of functional brain deficit secondary to hydrocephalus is little understood. Improvement of the patient's clinical status after drainage of CSF suggests that cerebral dysfunction is not necessarily due to permanent brain damage. In fact, it improves rapidly after ventricular taps. In view of this it would be helpful to monitor cerebral perfusion. The transcranial Doppler (TCD) ultrasonography technique allows real-time monitoring of the intracranial circulation and makes it possible to evaluate the physiopathological correlation between ventricular dilatation and CBF. Continuous monitoring of the middle cerebral artery (MCA) by TCD was performed in three hydrocephalic children (2 months, 14 months, and 8 years old) during a ventricular-peritoneal shunt operative procedure. A TC-2000S device provided by an IMP-F fixed probe was utilized. In all patients, when the lateral ventricle was shunted and the CSF could flow away, a clear and sudden increase of flow velocity above 30% was detected. The pulsatility index (PI) was also pathologically increased in all patients. A gradual normalization of this index was revealed after the shunting procedure. Our experience has to be considered preliminary, but nonetheless, it suggests a clear correlation between hydrocephalic disease and concomitant CBF alterations.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Flow Velocity↗
PubMed1994

Peritumoral edema in meningiomas: microsurgical observations of different brain tumor interfaces related to computed tomography.

Although generally benign tumors, meningiomas may be associated with extensive peritumoral brain edema as seen on computed tomographic scans. Fifty-two patients with intracranial meningiomas were studied, and the hypodense areas on computed tomographic scans were related to the intraoperative microsurgical findings and to the sizes of the tumors. We have identified three kinds of tumor-brain interfaces characterized by different difficulties in microsurgical dissection: smooth type, transitional type, and invasive type. These different microsurgical interfaces seem to correlate very precisely with computed tomographic images of halo-like and finger-like hypodense areas, allowing prediction of the microsurgical effort to be made in the surgery of meningiomas. The size of the tumor seems to be important in our subjects in determining the amount of edema produced. Indeed, a positive correlation (P < 0.001) was found between the sizes of the tumors and the extent of peritumoral hypodensity. A positive correlation (P < 0.002) also has been found between grade of edema and cortical penetration. Cerebral cortex disruption was systematically observed by us in invasive-type meningiomas and in 3 of 21 cases (14.3%) in transitional-type meningiomas. No penetration was observed in smooth-type meningiomas.

Blood-Brain Barrier↗
PubMed1991

Endothelin: an endothelium-derived vasoactive peptide and its possible role in the pathogenesis of cerebral vasospasm.

The contractile response to endothelin has been examined in cerebral arteries from rats subjected to a prior subarachnoid haemorrhage (SAH) and compared with saline injected controls. Endothelin elicited strong concentration-dependent contraction of rat basilar artery segments. The response was slow in onset and long lasting. The endothelin-induced contraction was much stronger in the SAH compared to control animals. Our findings suggest a role of the peptide in the pathophysiology of cerebral vasospasm.

Animals↗
PubMedDate not supplied

Experimental investigations on a model of cryogenic edema.

The role of mechanisms underlying formation and progression of vasogenic brain edema is investigated. On this purpose, cerebral edema was produced by cortical freezing in two different brain situations in rabbits (with or without replacement of bone flap). BBB (Blood-Brain Barrier) breakdown was evaluated by observation of Evans blue extravation, while a histopathological evaluation was carried out by light and transmission electron microscopy. Water content of brain tissue was determined by the wet/dry weight ratio method. Comparison of extension and intensity of cerebral edema between these two groups of animals shows a statistically significant difference: there was evidence of higher water content in the animals undergone replacement of bone flap. The Authors emphasize the importance of tissue pressure gradients in determining diffusion of cerebral edema.

Animals↗
PubMedDate not supplied

Pallidotomy improves quality of life in selected parkinsonian patients: an Italian report.

Pallidotomy has recently been reconfirmed as effective for otherwise intractable symptoms of Parkinson's disease. Nonetheless almost every aspect of its performance requires choices which are not fully established and may vary between centers. These include: 1) patient selection; 2) choice of imaging modality, 3) choice of anatomic landmarks for targeting the lesion, 4) choice of method for physiologic confirmation of location, 5) choice of lesion size and shape. We present two cases of pallidotomy procedures in Parkinsonian patients that in our knowledge are the first reported in Italy. Our experience and a careful review of the literature led to the following choices: 1) selection of Parkinsonian patients with dominant L-Dopa induced dyskinesia, akinetic and rigidity symptoms, 2) use of CT due to the distortion effects of MRI, 3) use of standard (Laitinen) coordinates combined with an image fusion method using MRI, 4) use of stimulation to gauge distance to internal capsule and optic tract, 5) production of vertical lesion covering internal segment of pallidum. At a 1-year follow-up the results include a 45% drop in UPDRS (Unified Parkinson's Disease Rating Scale) motor score and almost complete resolution of contralateral dopa induced dyskinesias in both patients.

Globus Pallidus↗