I.V. Yakovlev, V.A. Khachatryan, S.K. Korostylev, S.F. Gogoryan, A.S. Beskrovny, A.A. Kharlampyev
Polenov Research Neurosurgical Institute,
Kirov Medicomilitary Academy, Saint Petersburg, Russia
Municipal Clinical Center N 7, Komsomolsk on Amur, Russia
Occlusion of liquor pathways leads to impairment of ventricular-subarachnoid liquor flow. There appear ventriculomegaly and hydrocephalus-hypertension-dislocation syndrome. There are reports on transient occlusion of the aqueduct, caused by temporary narrowing of its lumen, but not by presence of a blastomatous mass or a cicatricial-proliferative process (Nugent et al., 1979; Khachatryan V.A., 1985,1989,1991; Sato et al., 1989). Besides, some reports describe transient occlusion of the lateral sinus, which was not conditioned by a mass, cicatrices or some other occluding process (Kinal, 1962; Khachatryan V.A., 1987,1990, 1991, 2000; Sainte-Rose et al., 1997; etc.). This disorder of patency of dural sinuses results in an increase of venous pressure within them and less marked difference between CSF pressure and venous pressure in the sagittal sinus due to impaired resorption of liquor. A rate, clinical course and pathogenesis of transitory occlusion of liquor pathways and dural sinuses needs further studying, though a role of this phenomenon in hydrocephalus evolution is extremely great.
Materials and Methods. Results of examination and treatment of 684 patients, aged 1-69, were analyzed. A degree and character of deformities of liquor cavities, impaired liquor circulation were estimated with the help of sonography, CT, MRI, PET, MR-angiography, liquorodynamic contrast studies, sinusography, catheterizaton angiography. Manifestations of transitory occlusion of liquor cavities and dural sinuses were revealed and estimated.
Results. Occlusion of liquor pathways was diagnosed in 1/10 of cases with internal biventricular, triventricular and tetraventricular hydrocephalus. The aqueduct occlusion was the most spread pathology; the next places were occupied by occlusion of foramens of the IV ventricle and Monro's foramen.
Transitory occlusion was associated with ventriculomegaly and liquor hypertension and accompanied by development of hydrocephalus-hypertension-dislocation syndrome. It disappeared after ventricles' puncture, CSF evacuation and ICP normalization.
Transient obstruction of dural sinuses was diagnosed in 1/7 of cases. It led to further aggravation of a clinical course of hydrocephalus. This transitory occlusion was watched against a background of ventriculomegaly, liquor hypertension and dislocation syndrome. It disappeared after CSF evacuation from the ventricles and ICP normalizaton. Occlusion of inferior segments of the sigmoid sinus near the jugular foramen was observed in the majority of cases. Occlusion of all sigmoid sinus was less fequent. Occlusion of the transverse sinus was a rarity.
Development of transitory occlusion of liquor pathways and basal sinuses led to further aggravation of liquor circulation impairement. Thus, there appeared a vicious circle, which can be respresented as follows: a supposed etiological factor - liquor circulaton impairement - ventriculomegaly - liquor hypertension - deformity of liquor pathways and dural sinuses - aggravation of liquor circulation disorders.
Successful elimination of this vicious circle is based on continuous evacuation of ventricular CSF, i.e. demands performing operations, aimed at ventricles drainage or liquor shunting.