Propofol EEG burst suppression in carotid endarterectomy.

BACKGROUND: The results of randomized trials indicate that carotid endarterectomy, performed with a low morbidity-mortality perioperative risk, is the best therapeutic option both for patients with high-grade symptomatic and asymptomatic stenosis. Since the main operative risk is represented by embolic or hemodynamic cerebral ischemia, it appears necessary to maintain an adequate intraoperative cerebral blood flow and to carry out a meticulous endarterectomy. METHODS: On the basis of these considerations we prospectively studied a series of 100 consecutive patients operated on for high-grade carotid stenosis, by using a protocol based on: 1) an accurate selection of patients for surgery; 2) meticulous surgical technique without any shunt; 3) perioperative cerebral protection by barbiturate or propofol; 4) pre- and postoperative medical treatment of risk factors. All patients of our series performed preoperatively brain CT scan, transcranial Doppler, carotid duplex scanning, four vessel angiography, brain 99mTc-HMPAO SPECT. Eighty-two patients had symptomatic carotid stenosis ranged between 70 and 90%, 18 had carotid stenosis higher than 90%. RESULTS: In this series there have been one postoperative death due to myocardial infarction and one major stroke. CONCLUSIONS: We think that this protocol can significantly minimize risks of endarterectomy and probably maximize the benefits of surgery, also in patients with asymptomatic high-grade carotid stenosis.

Cerebrovascular reactivity before and after carotid endarterectomy.

BACKGROUND: The hemodynamic relevance of internal carotid artery (ICA) stenosis often does not correlate with anatomic features, as angiographically defined. The cerebrovascular reactivity (CVR) has been advocated as a means of defining the cerebral hemodynamic impairment. METHODS: We assessed the results of pre- and postoperative CVR evaluation, using the CO2 transcranial doppler method, in 25 patients with high-grade ICA stenosis. The patients with history of stroke, evidence of cerebral CT infarction or symptoms from the contralateral circulation or the brain stem were excluded to avoid the effects of cerebral infarction on the hemodynamic studies. Statistical analysis was used to evaluate the CVR changes after carotid endarterectomy. RESULTS: Preoperative evaluation showed that CVR was generally well correlated with the degree of ICA stenosis and concomitant contralateral carotid steno-occlusion. Before endarterectomy the mean CVR value was 66.5% (moderately reduced). After surgery the overall mean value of CVR was 84.1% (normal), with a statistically significant improvement. CONCLUSION: The results of this study suggest that the CVR evaluation allows one to obtain hemodynamic information of clinical interest in the patients with ICA stenosis and that carotid endarterectomy is effective to restore the CVR in patients with cerebral hemodynamic impairment.

Congenital absence of the internal carotid artery.

We report three cases of congenital absence of an internal carotid artery (ICA), diagnosed incidentally by digital subtraction angiography. The analysis of the cases is based on the classification of segmental ICA agenesis proposed by Lasjaunias and Berenstein. Usually the patients with this rare vascular anomaly are asymptomatic; some may have symptoms related to cerebrovascular insufficiency, compression by enlarged intracranial collateral vessels, or complications associated with cerebral aneurysms. Diagnosis of congenital absence of ICA is made by skull base computed tomography (CT) scan, CT and magnetic resonance angiography, and conventional or digital subtraction angiography.

Callosotomy for generalized seizures associated with hypothalamic hamartoma.

A case is reported of intractable epilepsy associated with a hypothalamic hamartoma in an 18 year old man. The patient underwent a two-third anterior callsotomy and, subsequently, removal of the hamartoma. Callosotomy did not affect the generalized seizure pattern. The authors believe this to be the first documented case of hypothalamic hamartoma in which callosotomy for seizure control was attempted. The poor response to callosotomy suggests the extracallosal diffusion of the generalized seizures from hypothalamic hamartomas.

Reconstruction of peripheral nerves: the phenomenon of bilateral reinnervation of muscles originally innervated by unilateral motoneurons.

It is well known that after reconstruction of sectioned peripheral nerves in adult mammals, denervated muscles are reinnervated by the axotomized motoneurons lying in the original motonucleus. It is less well known that these muscles can also be reinnervated by uninjured motoneurons lying in the homologous contralateral motonucleus. Therefore, after nerve reconstruction, bilateral motoneuron reinnervation of muscles can occur. Contralateral motoneurons sprout axons that cross the midline, grow in the reconstructed nerve, and reach muscle targets. This phenomenon was observed after reconstruction of several different peripheral nerves in adult mammals, including the oculomotor nerve in guinea pigs and the facial and sciatic nerves in rats. The retrograde axonal transport of horseradish peroxidase was used for the study of the organization of the brainstem and spinal cord motonuclei. Horseradish peroxidase was injected into the medial rectus muscle, the stylohyoid muscle, and the trunk of the sciatic nerve. The distance between the homologous motonuclei of both sides influenced the occurrence of this phenomenon. In fact, bilateral reinnervation of muscles after nerve reconstruction was found in 36% (sciatic nerve), 50% (facial nerve), and 100% (oculomotor nerve) of the operated animals. The total number of contralateral motoneurons found were 14% (oculomotor nerve), 8% (facial nerve), and 5% (sciatic nerve). Bilateral reinnervation of muscles was evoked by both immediate and delayed peripheral nerve repair and was a stable phenomenon, seen between 3 and 21 months after facial nerve reconstruction.

Bone metastasis associated with shunt-related peritoneal deposits from a pineal germinoma. Case report and review of the literature.

The case of a 15-year-old boy with a pineal germinoma is reported. The patient first underwent a ventriculoperitoneal (VP) shunt followed by a stereotactic biopsy, then, because of the rapidly deteriorating neurological status, an emergency craniotomy with subtotal removal of the tumour was performed. Two months after surgery, a left femoral metastasis and extensive peritoneal lesions became evident; they were regarded as due to haematogenous and VP shunt spread of the germinoma. At that time, extremely high serum levels of placental alkaline phosphatase were detected. The patient died 6 months after the initial diagnosis. The occurrence of extraneural metastases as well as of shunt related peritoneal deposits from primary intracranial germinoma is discussed. As far as we know this is the first reported case of a combination of haematogenous as well as VP shunt spread of a pineal germinoma.

Levocarnitine acetyl promotes the regeneration of peripheral sensory axons and reduces the hypertrophy of axotomized spinal cord motoneurons in rats.

In previous studies, the neurotrophic action of levocarnitine acetyl on the regeneration of the sciatic nerve in rats has been demonstrated. The present study investigated the particular effect of levocarnitine acetyl on the initial stages of sciatic nerve regeneration. In the first 8 days after sciatic nerve lesion caused by crushing (Group A) or cutting (Group B), the rats of both groups were divided into 2 subgroups: treated rats received daily intraperitoneal levocarnitine acetyl (a megadose of 100 mg in saline solution); untreated rats only received saline solution. Treatment started on the day of operation. The regeneration growth rate of sensory fibres was studied using the pinch test. The size of the axotomized spinal motoneurons was studied using retrograde axonal tracers (horseradish peroxidase or Fast blue). The results showed that: (a) levocarnitine acetyl promoted the elongation of sensory fibres in the first 8 days following the crushing or sectioning of the sciatic nerve, but the data were only statistically significant (p less than 0.01) for the first 3 days after crushing; (b) levocarnitine acetyl accelerated the velocity of sensory fibre regeneration when compared to untreated rats by 16% in the first 3 days after nerve crushing, by 14% in the first 4 days after nerve section, and by 32% from the 5th to the 8th day after nerve section; (c) levocarnitine acetyl promoted a significant reduction in spinal motoneuron hypertrophy when compared to untreated rats at both 4 and 8 days after sciatic nerve section.(ABSTRACT TRUNCATED AT 250 WORDS)