Experimental study and clinical use of poly(vinyl acetate) emulsion as liquid embolisation material

A new material, an emulsion of poly(vinyl acetate) was experimentally developed and clinically used to overcome several disadvantages in currently used liquid embolisation materials. The emulsion microparticles, 0.3–0.7 m in size, possessed cationic charge on the surface and hence aggregated immediately on contact with fluids containing anions. This inert polymer has the advantage that it does not induce a deleterious reaction in living tissue. Moreover, its medium is water and it is not adhesive, like the cyanoacrylates. Several concentrations of emulsion were injected into the renal arteries of dogs. For the investigation of tissue reactions and the possibility of recanalisation, the emulsion was injected into rats both subcutaneously and into the renal arteries. The renal artery injections in dogs showed adequate radiopacity and consistent complete occlusion. The lower the concentration of the emulsion, the smaller the arteries which could be occluded. Even at very low concentrations, however, venous occlusion did not occur. Histological study of the embolised rat kidney revealed no detectable damage in the vessel wall and no recanalisation for up to 6 months. The subcutaneously injected PVAc emulsion elicited mononuclear cell infiltration and gradual centripetal fibrosis, without any deleterious effect on the surrounding tissue. A cerebral arteriovenous malformation (AVM) was embolised using the material. Histology of the resected nidus showed findings similar to those in the animal experiments.     

Cerebral arteriovenous malformations in children

The treatment of cerebral arteriovenous malformations (AVM) or vascular anomalies are challenging neurosurgical procedures for an anaesthetist. Large AVMs are uncommon in children. Only 18% of AVMs become symptomatic before the age of 15 yr. This series reviews the experience at this institution during the period of 1982 to 1992. The symptoms at the time of presentation are varied and include haemorrhage (50%), seizures and hydrocephalus (36%) or congestive cardiac failure (18%). Symptoms of congestive heart failure predominate in the new-born whilst neurological symptoms, such as stroke, seizures or hydrocephalus occur more commonly in infants and older children. Approximately one third of AVMs in childhood present acutely. Radiological investigations, e.g., CT scan, MRI and cerebral angiography are essential to identify the precise location of the lesion. Therapeutic intervention in the acute presentation may involve craniotomy for evacuation of haematoma and treatment of increased intracranial pressure (ICP). Control of seizures and congestive heart failure may take priority and allow time to plan the elective procedures of embolization and surgical excision of the AVM. Operative intervention is hazardous and peroperative complications can be expected in more than 50% of patients. The morbidity and mortality associated with cerebral AVM are high, especially in infants who present in the neonatal period with congestive cardiac failure. The overall mortality in this series was 20%. Children presenting with intracranial arteriovenous malformations require a multidisciplinary approach. The successful management of anaesthesia either for embolization or surgical resection necessitates an understanding of the disciplines of paediatric and neuroanaesthesia. Special care and specific attention to detail may contribute to reduce the high morbidity and mortality encountered in these compromised children.     

Single forebrain ventricle without prosencephaly: agenesis of the corpus callosum with dehiscent fornices

Coalescence of the cerebral ventricles with formation of a single forebrain ventricle is described in an unusual case of agenesis of the corpus callosum with dehiscent fornices and severe hydrocephalus. The cerebral hemispheres were fully cleaved. The detached fornices were widely separated from the thalami. The membrana tectoria was retroverted over the midbrain and cerebellum, where it joined the fornices and merged with a curved membranous ependymal dome which, at a great distance, circumvented the thalami as it extended toward the anterior commissure. Other anomalies included arhinencephaly, multiple subependymal heterotopias, and Dandy-Walker malformation. Similar malformations have been described as interhemispheric cysts, as (holo)prosencephaly, or as midline telencephalic dysgenesis. The basic features of prosencephaly and agenesis of the corpus callosum are reviewed and compared to the present case.     

静脉内支撑治疗布-加综合征

目的：评估静脉内支撑治疗布－加（Ｂｕｄｄ－Ｃｈｉａｒｉ）综合征的应用价值。方法：①下腔静脉完全梗阻者,根据阻塞长度置入可扩张性内支撑架;②门静脉高压者,在下腔静脉球囊扩张的同时行颈内静脉肝内门体分流术（ＴＩＰＳＳ）治疗后再置入内支撑架;③肝静脉狭窄或闭塞者,扩张肝静脉远端后再植入内支撑架。结果：所有患者均获得操作成功。手术后临床症状明显改善,下腔静脉压差和门静脉压力显著下降。随访８例下腔静脉内支撑和肝内门体分流道通畅良好。结论：静脉内支撑治疗布－加综合征疗效良好     

Cavernous Haemangiomas of the Spinal Cord. A Review of 117 Cases

 The data of 48 studies (published between 1903 and 1996), presenting information of all together 107 patients (108 lesions) regarding pre-treatment clinical and radiological factors, treatment strategies, and the outcome, plus our own experience of nine patients were retrospectively re-analyzed. The prognostic influence of pre-treatment factors was estimated with the chi-square statistics. Clinical evaluation before/after treatment was performed using the Frankel scale. The average bleeding rate was obtained from the ratio of percentage of first bleeding events in the population to the mean age of the population.  There were 47 males and 69 females (aged from twelve to 88 years). Thirty nine percent of the lesions were found in the cervical, 54% in the thoracic (30% upper, 24% lower) and 7% in the lumbar cord. The peak age of presentation was in the fourth decade, the median duration of symptoms was 32 months. Clinical symptoms before treatment were progressive in all cases. Three patterns of clinical presentation could be identified: a) episodes of stepwise clinical deterioration (30%), b) slow progression of neurological decline (41%), c) acute onset with rapid or gradual decline over weeks or months (26%). 58% of the lesions showed clinical or radiological signs of haemorrhage. In 66% of surgical patients (91 efficiently documented cases), clinical improvement was achieved, 28% remained unchanged and 6% deteriorated. Whereas age, sex and lesion location had no influence on the results, duration of symptoms (<three years) correlated significantly to a better outcome (p<0.02).  Surgical management in symptomatic patients is recommended. Once clinical signs caused by the malformation have appeared, the patients tend to experience progressive neurological deterioration.     

An angiographically occult arteriovenous malformation in the medial parietal lobe presenting as seizures of medial temporal lobe origin

We present an unusual case of a patient who was diagnosed with temporal lobe epilepsy and whose seizures were reduced markedly after excision of an angiographically occult arteriovenous malformation (AVM) located in the left medial parietal lobe. A 38-year-old man had complex partial seizures characterized by motionless staring with oroalimentary and behavioral automatisms since the age of 15 years. Magnetic resonance imaging (MRI) demonstrated a small lesion extending from the left posterior cingulate gyrus to the precuneus. There was no MRI evidence of mesial temporal sclerosis. Intracranial EEG recordings showed ictal onset from the left medial parietal lobe propagating to the medial temporal lobes. Clinical signs appeared when these discharges reached the temporal lobes. After excision of the lesion (which was histologically confirmed as an AVM), together with the marginal cortex, seizures were reduced significantly. Careful diagnostic evaluation of lesions such as the this one may reveal an epileptogenic lesion (zone) far from the region where scalp ictal discharges seem to arise. In our case, we hypothesize that false localization was due to propagation of ictal discharges from the parietal focus through the limbic system.     

Perinatal autopsy—A seven-year study

A retrospective analysis of autopsies conducted on perinatal deaths during 7 years period (Oct 1983 to Sept 1990) was done. There were 650 neonatal deaths and 944 still births during the study period. Autopsy rates among neonates and still births were 33% and 4.9% respectively. There ware significant findings in 97.2% of neonatal deaths and in all still births. Pulmonary lesions followed by congenital malformations were the major pathological findings. Infection was observed among smaller number of babies compared to other Indian studies. Autopsy revealed many internal congenital malformations which were not diagnosed clinically. Autopsy changed or added to clinical diagnosis in 59.5% of cases. Perinatal autopsy is highly productive in our set up.     

Cerebral venous angiomas: Surgery as a mode of treatment for selected cases

Summary Eleven patients with venous angiomas, 6 males and 5 females ranging in age from 4 to 58, are presented. Four patients presented with intracerebral haematoma and 3 patients had associated cavernous angioma, respectively. Patients with intracerebral haematoma had signs and symptoms due to the localication of the haematoma. The other patients presented with headache, seizures, vertigo, ataxia and mental disturbances. Pre-operative diagnosis was based on computerized tomography, magnetic resonance imaging and cerebral angiography. In 9 surgical cases it was confirmed by histopathological examination of operative specimens.After establishing the type, size and location of the lesion decision for operative treatment was made in nine cases, in four of them because of the presence of an intracerebral haematoma and in 5 of them due to severe disability. Eight of these 9 patients recovered completely and one improved. No severe cerebral oedema was encountered after converging medullary veins were excised and main draining veins partially coagulated.In this small series we encountered an unexpectedly large percentage of venous angiomas causing intracerebral haemorrhage which are commonly considered more benign than other vascular malformations. After reviewing previously reported cases of venous angiomas causing intracerebral haemorrhage and severe neurological deficit we think that the term benign is worth reconsidering. We propose a thorough examination of each case of venous angioma and the operative treatment when appropriate taking into account patients state and location of angioma.     

Benign intracranial hypertension vs. intracranial arteriovenous malformation: A possible CT dilemma

Summary A nine-year-old boy, presenting only with signs of increased ICP, underwent computerized tomography. This examination demonstrated no abnormalities in the precontrast scan. Following C. E., it showed scattered areas of blood-like density in both hemispheres, as well as a presumedly abnormal vessel in the left occipital region and dilated vein of Galen, sinus rectus, and tentorial veins. The presumptive diagnosis of left occipital AVM was not confirmed by angiography, which also ruled out obstructions of the intracranial sinuses.The possible mechanism responsible for this atypical CT picture is briefly discussed in the light of pertinent literature. It is suggested that careful consideration should be given to the indications for angiography in similar cases, in the presence of a hypervascular aspect of the postcontrast CT scan, particularly if a considerable amount of contrast medium has been used.