Investigation of the effect of different degrees of flexion and extension of the neck on internal jugular vein and carotid artery flows in presence of supratentori̇al lesions

During intracranial surgery, variable patient positions may be used according to the location of the lesion. Vascular structures of the neck could be under pressure while flexion, extension or rotation of the head during the surgical patient positioning. This situation may lead to not only various problems such as increase of the intracerebral pressure and cerebral ischemia, but also difficulty for surgical approach. In this study, among patiens who are planned to be operated for a supratentorial lesion, it was aimed to compare the effect of 300 flexion and 300 extension of neck to internal carotid artery and internal jugular vein flows and flow velocity using magnetic resonance imaging and doppler ultrasonogaphy. MATERIAL AND METHODS After local ethical committee approvement and taken written consent from patients, 20 patients who are planned to be operated because of a supratentorial intracranial tumour, aged between 18-60 yrs, ASA status I-II , BMI 20-25; does not have clinically detected vascular or cervical pathology (lack of movement in cervical area, being operated from intracranial or cervical region, history of stroke, atherosclerosis, stenosis etc.), symptoms of increased intracranial pressure or a need for sediation during the magnetic resonance imaging. Demographic charactheristic of the patients, such as age, sex, BMI; the location, type and the side of the tumor was recorded. Following 8 hours period of fasting, the patients were taken to doppler ultrasonography unit; flow and flow velocity measurements of internal carotid artery and internal jugular vein were taken from 1cm above of common carotid artery bifurcation in three different positions; neutral position, 300 flexion and 300 extension of head. Afterwards the patients were taken to magnetic resonance imaging unit and internal carotid artery and internal jugular vein flow velocity measurements were taken in neutral position, 300 flexion and 300 extension of head in two different velocity encoding sequences (50ml/sn and 100ml/sn). While measurements were taken in both techniques; in order to give flexion and extension position to head, fibroelastic material-made standart equipment was used and the 300 angle was measured. In means of follow-up of heamodynamic sudden changes; during the measurements, the oxygen saturations by a pulse oxymetry, heart rates and non-invasive blood pressure values of patients were monitored. All collected datas were evaluated statistically. RESULTS According to the comparison of the arterial and venous blood flow; blood flow was elevaten in %25 percent of the patiens on the same side of the tumour. There was no statistically difference for internal carotid artery and internal jugular vein flow velocity measurements using by doppler ultrasonography and magnetic resonance imaging in the neutral, 300 flexion and 300 extension positions of the head (p> 0.05). Also there was no statistically difference for internal carotid artery and internal jugular vein flow measurements using by doppler ultrasonography and magnetic resonance imaging in the neutral, 300 flexion and 300 extension positions of the head (p> 0.05). There was a correlation between doppler ultrasonography and magnetic resonance imaging blood flow velocity measurements taken in velocity encoding 50ml/sn sequence (pearson correlation number ≥60). The correlation was statistically significant especially in venous blood flow velocity measurements (pearson correlation number ≥80). CONCLUSION The 30 degree flexion and 30 degree extension positions of the head does not effect the internal carotid artery and internal juguler vein flow and flow velocitie in patients who have supratentorial tumour and planning craniotomy. During craniotomy, the documentation of the limits of flexion and extension movement of the head using measurement techniques will contribute the success of surgery, also has importance in means of morbidity and mortality of the patients.