Effects of bilateral jugular vein ligation on intracranial pressure and cerebrospinal fluid outflow resistance in cats

Venous dynamics in anesthetized sheep govern postural-induced changes in cerebrospinal fluid pressure comparable to those in humans

Sheep are popular large animals in which to model human disorders and to study physiological processes such as cerebrospinal fluid dynamics. However, little is known about vascular compensatory mechanisms affecting cerebrospinal fluid pressures during acute postural changes in sheep. Six female white Alpine sheep were anesthetized to investigate the interactions of the vascular and cerebrospinal fluid system by acquiring measurements of intracranial pressure and central and jugular venous pressure during passive postural changes induced by a tilt table. The cross-sectional area of the common jugular vein and venous blood flow velocity was recorded. Anesthetized sheep showed bi-phasic effects of postural changes on intracranial pressure during tilting. A marked collapse of the jugular vein was observed during head-over-body tilting; this is in accordance with findings in humans. Active regulatory effects of the arterial system on maintaining cerebral perfusion pressure were observed independent of tilting direction. Conclusion: Anesthetized sheep show venous dynamics in response to posture-induced changes in intracranial pressure that are comparable with those in humans.

Cerebral venous congestion exacerbates cerebral microhemorrhages in mice

Cerebral microhemorrhages (CMHs; microbleeds), which are small focal intracerebral hemorrhages, importantly contribute to the pathogenesis of cognitive decline and dementia in older adults. Although recently it has been increasingly recognized that the venous side of the cerebral circulation likely plays a fundamental role in the pathogenesis of a wide spectrum of cerebrovascular and brain disorders, its role in the pathogenesis of CMHs has never been studied. The present study was designed to experimentally test the hypothesis that venous congestion can exacerbate the genesis of CMHs. Increased cerebral venous pressure was induced by internal and external jugular vein ligation (JVL) in C57BL/6 mice in which systemic hypertension was induced by treatment with angiotensin II plus L-NAME. Histological analysis (diaminobenzidine staining) showed that mice with JVL developed multiple CMHs. CMHs in mice with JVL were often localized adjacent to veins and venules and their morphology was consistent with venous origin of the bleeds. In brains of mice with JVL, a higher total count of CMHs was observed compared to control mice. CMHs were distributed widely in the brain of mice with JVL, including the cortical gray matter, brain stem, the basal ganglia, subcortical white matter, cerebellum, and the hippocampi. In mice with JVL, there were more CMHs predominantly in cerebral cortex, brain stem, and cerebellum than in control mice. CMH burden, defined as total CMH volume, also significantly increased in mice with JVL. Thus, cerebral venous congestion can exacerbate CMHs. These observations have relevance to the pathogenesis of cognitive impairment associated with right heart failure as well as elevated cerebral venous pressure due to jugular venous reflux in older adults.

A novel rat model of cerebral artery occlusion complicated with prior venous stagnation

BACKGROUND

To establish a novel rat model of middle cerebral artery occlusion (MCAO) complicated with prior venous stagnation, and to investigate the role of cerebral venous drainage in neural injury after acute cerebral infarction.

NEW METHOD

Eighteen SD rats were randomly divided into two groups: control group and jugular vein ligation group. The left jugular vein ligation was performed to produce the jugular venous stagnation. In the control group, the jugular vein was exposed but not ligated. Cerebral blood flow (CBF) was measured through laser speckle imaging before and after the surgery. At 1 week after the surgery, CBF was again measured and then a left MCAO was performed in both groups. At 24 h after MCAO, neurological deficit scoring was performed and the infarct volume was measured by 2,3,5-triphenyltetrazolium chloride staining.

RESULTS

Compared with the control group, a significant decrease in the CBF level was observed immediately after the ligation. A moderate recovery in CBF level was observed at 1 week after the ligation. The neurological deficit scores were significantly higher in the ligation group than in the control group at 24 h after the MCAO. Additionally, the volume of cerebral infarction increased significantly in the ligation group compared with that in the control group at the 24 h after MCAO.

COMPARISON WITH EXISTING METHOD(S) AND CONCLUSIONS

The novel rat model of cerebral artery occlusion complicated with long-term unilateral venous stagnation indicates cerebral venous drainage impairment may aggravate behavioral impairment and increase infarct volume after cerebral infarction.

Agenesis of internal jugular vein a cause for concern

Internal jugular vein is one of the major contributors to the venous drainage from the intracranial structures. Neck dissections which necessitates ligation of internal jugular vein leads to significant alteration of cerebrospinal fluid pressures in the range of three times for unilateral ligation to five times in cases of bilateral ligation. Agenesis of internal jugular vein merits concern prior to central venous cannulation and ligation during radical neck dissection for metastatic nodes in head and neck cancers.

Effects of bilateral jugular vein ligation on local cerebral blood flow

The authors examined the effect of bilateral jugular vein ligation (JVL) on local cerebral blood flow (CBF). Local CBF was measured in the neocortex of the frontal lobe over a 1-week period in 10 freely moving male rats. Measurements were taken with the hydrogen clearance method before and after the rat underwent either an operation of bilateral JVL or a sham operation. After the sham operation, blood flow values did not change significantly compared with preoperative values. Blood flow values decreased rapidly in rats with JVL. For 3 hours after surgery, JVL values were significantly lower (p <0.05) than preoperative values were, then gradually they recovered and reached preoperative values within 48 hours. Histopathologic study showed no remarkable parenchymal damages in the brain of rats with JVL. These results show that bilateral JVL produces a reversible decrease in the CBF and does not cause histopathologic brain damages.

Vantagens da conservação da veia jugular interna nos esvaziamentos cervicais unilaterais

OBJETIVO: Diante da dúvida sobre a existência ou não de vantagens relacionadas à conservação da veia jugular interna nos esvaziamentos cervicais unilaterais resolvemos observar se os pacientes que a tem sacrificada apresentam alterações ao exame de fundo de olho que indiquem um aumento da pressão intracraniana, avaliar a presença de alterações neurológicas e verificar as vantagens na evolução clínico-cirúrgica dos pacientes que tiveram a sua veia jugular interna conservada. MÉTODO: Trata-se de estudo prospectivo, não randomizado, de 15 pacientes portadores de carcinoma epidermóide da cabeça e pescoço, atendidos e operados no Serviço de Cirurgia de Cabeça e Pescoço do Hospital Heliópolis, que tiveram como parte de seu tratamento a realização de esvaziamento cervical completo (funcional ou não) unilateral, divididos em um grupo com ressecção da veia jugular interna e outro com sua conservação. Todos foram submetidos a exames de retinografia pré e pós-operatórios, além de avaliação neurológica e clínica. RESULTADOS: Não ocorreram alterações oftalmológicas detectáveis através da retinografia em nenhum dos grupos. O grupo que teve sua veia jugular interna ressecada apresentou maior incidência de queixas neurológicas no pós-operatório, além de uma evolução cirúrgica mais desfavorável, com um maior período de internação devido às complicações locais apresentadas. CONCLUSÕES: A conservação da veia jugular interna nos esvaziamentos cervicais unilaterais beneficia a evolução pós-operatória dos pacientes, com um menor período de internação, apesar de não termos identificado qualquer evidência pós-operatória de aumento da pressão intracraniana nos pacientes que tiveram a veia ligada.

Traumatic bilateral jugular vein thrombosis: case report and review of the literature

OBJECTIVE AND IMPORTANCE

Thrombosis of the internal jugular vein (IJV) with associated elevated intracranial pressure (ICP) is a rare complication of central venous catheterization but has not been reported as a result of blunt trauma.

CLINICAL PRESENTATION

An 18-year-old male patient was observed to be obtunded after an assault. The initial examination was remarkable for somnolence, bruising of the anterior neck, and diffuse, edematous swelling of the face and scalp. The results of computed tomography of the brain were normal. An angiogram obtained on the 2nd hospital day to rule out carotid injury revealed bilateral IJV thromboses to the cranial base. An ICP monitor was placed with an opening pressure of 33 mm Hg. The central venous pressure was measured to be 9 mm Hg. A catheter was passed through the left IJV thrombus and into the sigmoid sinus, where the pressure was 17 mm Hg.

INTERVENTION

An intravascular stent was deployed in the left IJV. ICP rapidly normalized. A regimen of coumadin was administered to the patient for 6 weeks, at which time the stent remained patent.

CONCLUSION

We conclude that traumatic jugular vein thrombosis can be associated with significant elevation in ICP and that treatment with an endovascular stent can affect the rapid correction of intracranial hypertension in patients who are candidates for anticoagulation.

Posterior ischemic optic neuropathy following bilateral radical neck dissection

A patient is presented with posterior ischemic optic neuropathy (PION) after bilateral radical neck dissection, probably caused by hemodynamic hypotension, combined with other factors. A postmortem histologic study of the optic nerve was performed to analyze the pathogenic mechanism of blindness. To prevent this complication, one should favor a two-stage procedure, avoiding drug-induced hypotension, overtransfusion, and anemia. During the postoperative period, visual acuity should be monitored regularly, and proper positioning of the patient's head is necessary.