[Subocclusive transvenous approach of dural arteriovenous fistula]

INTRODUCTION

Dural arteriovenous fistulae (DAVF) are usually acquired and when presented with cortical venous drainage are associated with high risk of hemorrhage. They can be treated by arterial or venous embolization, by surgery or by the combination of both techniques. Transvenous approach induces venous sinus thrombosis increasing the risk of venous stroke and/or hemorrhage.

OBJECTIVE

Review of all the cases of transvenous embolization of lateral sinus arteriovenous fistulas treated in our department. Our main objective is to evaluate the clinical/imaging results of this treatment and the second goal is to discuss possible advantages of the subocclusive approach in the first session of transvenous treatment.

RESULTS

The authors present six clinical cases of DAVF with the following clinical symptoms: visual disturbances (3); ear pulsatile bruit (3); headaches (2); subarachnoid hemorrhage (1); subjective hearing loss (1); optic disc edema (1); hemiparesis (1). Angiographic classification was: Cognard IIa, (3), IIab (2) e IV (1), all of the lateral sinus. The main afferent branches arised from: ipsilateral ECA (6); ipsilateral ICA (6); ipsilateral VA (6); contralateral ECA (5); contralateral VA (5); contralateral ICA (3); ipsilateral PCA (1). Transarterial approach was the first approach in all patients with satisfactory but transient results. It was always followed by transvenous embolization of the lateral sinus with GDC coils. Subocclusive approach was achieved in five patients with the persistence of some afferent arteries. Follow-up angiography in four of them showed "spontaneous" thrombosis of the lateral sinus with clinical and angiographic cure. Thrombosis occurred once during the initial transvenous procedure. There were no complications or new neurological signs or symptoms in any patient.

CONCLUSIONS

Transvenous treatment of DAVF has led to technical and clinical success without procedure complications. We think that subocclusive approach of the venous sinus with coils can cause less hemodynamic changes with a slower thrombosis rate and less complications, unchanging the angiographic and clinical resolution.

Task-specific contribution of the human striatum to perceptual-motor skill learning

Acquisition of new perceptual-motor skills depends on multiple brain areas, including the striatum. However, the specific contribution of each structure to this type of learning is still poorly understood. Focusing on the striatum, we proposed (a) to replicate the finding of impaired rotary pursuit (RP) and preserved mirror tracing (MT) in Huntington's disease (HD); and (b) to further explore this putative learning dissociation with other human models of striatal dysfunction (i.e., Parkinson's disease and focal vascular damage) and two new paradigms (i.e., Geometric Figures, GF, and Control Stick, CS) of skill learning. Regardless of the etiology, participants with damage to the striatum showed impaired learning of visuomotor tracking skills (i.e., RP and GF), whereas the ability to learn skills that require motor adaptation (i.e., MT and CS) was not affected. These results suggest a task-specific involvement of the striatum in the early stages of skill learning.

Severe diaphragmatic hernia treated by fetal endoscopic tracheal occlusion

OBJECTIVES

To examine operative and perinatal aspects of fetal endoscopic tracheal occlusion (FETO) in congenital diaphragmatic hernia (CDH).

METHODS

This was a multicenter study of singleton pregnancies with CDH treated by FETO. The entry criteria for FETO were severe CDH on the basis of sonographic evidence of intrathoracic herniation of the liver and low lung area to head circumference ratio (LHR) defined as the observed to the expected normal mean for gestation (o/e LHR) equivalent to an LHR of 1 or less.

RESULTS

FETO was carried out in 210 cases, including 175 cases with left-sided, 34 right-sided and one with bilateral CDH. In 188 cases the CDH was isolated and in 22 there was an associated defect. FETO was performed at a median gestational age of 27.1 (range, 23.0-33.3) weeks. The first eight cases were done under general anesthesia, but subsequently either regional or local anesthesia was used. The median duration of FETO was 10 (range, 3-93) min. Successful placement of the balloon at the first procedure was achieved in 203 (96.7%) cases. Spontaneous preterm prelabor rupture of membranes (PPROM) occurred in 99 (47.1%) cases at 3-83 (median, 30) days after FETO and within 3 weeks of the procedure in 35 (16.7%) cases. Removal of the balloon was prenatal either by fetoscopy or ultrasound-guided puncture, intrapartum by ex-utero intrapartum treatment, or postnatal either by tracheoscopy or percutaneous puncture. Delivery was at 25.7-41.0 (median, 35.3) weeks and before 34 weeks in 65 (30.9%) cases. In 204 (97.1%) cases the babies were live born and 98 (48.0%) were discharged from the hospital alive. There were 10 deaths directly related to difficulties with removal of the balloon. Significant prediction of survival was provided by the o/e LHR and gestational age at delivery. On the basis of the relationship between survival and o/e LHR in expectantly managed fetuses with CDH, as reported in the antenatal CDH registry, we estimated that in fetuses with left CDH treated with FETO the survival rate increased from 24.1% to 49.1%, and in right CDH survival increased from 0% to 35.3% (P < 0.001).

CONCLUSIONS

FETO in severe CDH is associated with a high incidence of PPROM and preterm delivery but a substantial improvement in survival.

Neonatal pyruvate dehydrogenase deficiency due to a R302H mutation in the PDHA1 gene: MRI findings

Pyruvate dehydrogenase (PDH) deficiency is one of the most common causes of congenital lactic acidosis. Correlations between the genetic defect and neuroimaging findings are lacking. We present conventional and diffusion-weighted MRI findings in a 7-day-old male neonate with PDH deficiency due to a mosaicism for the R302H mutation in the PDHA1 gene. Corpus callosum dysgenesis, widespread increased diffusion in the white matter, and bilateral subependymal cysts were the main features. Although confirmation of PDH deficiency depends on specialized biochemical analyses, neonatal MRI plays a role in evaluating the pattern and extent of brain damage, and potentially in early diagnosis and clinical decision making.

[Neuro-Behçet: MR study of a group of patients]

Behçet's disease is a chronic inflammatory, multisystemic disease of unknown aetiology. Central nervous system involvement occurs in a variable proportion of cases (4 to 49%) and is due to intracranial hypertension secondary to dural sinus thrombosis, inflammatory parenquimal lesions or recurrent meningoencephalitis. We reviewed 12 patients, 7 men and 5 women, aged between 27 to 40 years at the time of diagnosis. Neurological manifestations were secondary to parenquimal lesions in 7 patients, meningoencephalitis in 3 patients (including one with extensive medullary lesion) and dural sinus thrombosis in 2. Magnetic Resonance (MR) findings in Neuro-Behçet are non-specific. Nevertheless, MR has a role in characterizing brain lesions topography, helping in the diagnosis and in the follow-up of these patients.

The close relationship between estimated divergent selection and observed differentiation supports the selective origin of a marine snail hybrid zone

To study the role of divergent selection in the differentiation of the two morphs in a hybrid zone of the intertidal snail Littorina saxatilis, we compared the strength of the divergent selection acting on a series of shell characters (as estimated by the viability of snails in a reciprocal transplant experiment) with the contribution of these characters to the phenotypic differences between the morphs. We found a close correlation between selection and differentiation, which suggests a cause-effect relationship, i.e. that all present differentiation is the result of past divergent selection. In addition, divergent selection was a very important component of the total natural selection acting on shell measures. These novel results support previous evidence, based on allozyme analysis, of a parapatric origin for this hybrid zone. We discuss possible limitations of this interpretation and the circumstances under which allopatric differentiation would produce the same results. Phenotypic analysis of divergent selection may be a useful method of investigating the evolutionary mechanisms involved in differentiation processes.

Testing alternative models for sexual isolation in natural populations of Littorina saxatilis: indirect support for by-product ecological speciation?

Two ecotypes of the rough periwinkle Littorina saxatilis occur at different shore levels, showing assortative mating for size and partial reproductive isolation when they meet at the mid-shore. This system represents a putative case of incomplete speciation in sympatry. Two processes contribute to the assortative mating: morph-specific microhabitat aggregation and mate choice. The estimation of mate choice coefficients in nature and a simulation of the aggregation effects on sexual isolation were used to disentangle these processes as well as to test alternative mechanisms of mate choice. Mate choice significantly increased the frequency of within-morph pairs and significantly decreased the frequency of between-morph pairs, whereas those pairs including at least one hybrid morph mated randomly. These results allow us to reject a discriminant mate choice and support a model of evolution of sexual isolation as a side-effect of size-assortative mating in a context of divergent natural selection for size in the population. This mechanism is more compatible with a model of incomplete by-product ecological speciation, as suggested by previous evidence.