[Russian study on brain aneurysm surgery: a continuation (RIHA II)]. / Rossiiskoe issledovanie po khirurgii anevrizm golovnogo mozga: prodolzhenie (RIKhA II).

OBJECTIVE: To assess the main performance indicators of neurosurgical departments in surgical treatment of cerebral aneurysms in the Russian Federation. MATERIAL AND METHODS: We analyzed 22 neurosurgical departments (19 regional and 3 federal hospitals) in 2017 and 2021. The study enrolled 6.135 patients including 3.160 ones in 2017 and 2.975 ones in 2021. We studied the features of surgical treatment of cerebral aneurysms in different volume hospitals and factors influencing postoperative outcomes. RESULTS: The number of surgeries for cerebral aneurysms decreased from 2.950 in 2017 to 2.711 in 2021. Postoperative mortality rate was 6.3% and 5.6%, respectively. The number of microsurgical interventions decreased from 60% in 2017 to 48% in 2021. The share of endovascular interventions increased from 40% to 52%, respectively. Endovascular embolization was accompanied by stenting in 55% of cases. Simultaneous revascularization was carried out in 2% of cases. In 2021, the number of patients undergoing surgery in acute period of hemorrhage increased to 70% (in 2017 - 61%). The number of hospitals performing more than 50 surgical interventions for cerebral aneurysms annually increased from 14 in 2017 to 17 in 2021. CONCLUSION: Certain changes in neurosurgical service occurred in 2021 compared to 2017. Lower number of surgical interventions for cerebral aneurysms, most likely caused by the COVID-19 pandemic, is accompanied by lower postoperative mortality. Endovascular interventions and revascularization techniques became more common. The number of surgeries in acute period after aneurysm rupture and hospitals performing more than 50 surgical interventions for cerebral aneurysms annually increased.

Effect of stimulation of the reticular nucleus of the thalamus on neuronal activity of associative and nonspecific thalamic structures.

The reactions of neurons of the centromedian, mediodorsal, and posterior lateral nuclei of the thalamus to electrostimulation of its reticular nucleus were studied in experiments on anesthetized cats. A high reactivity of neurons of the centromedian (53.7%) and mediodorsal (48.3%) nuclei in comparison with the posterior lateral (10%) was established. "Silent" neurons reacted by an excitatory type of reaction having a phasic chamber. Primary and secondary inhibitory reactions were noted among the spontaneously active neurons. The latent period of the excitatory reactions of the neurons of the centromedian nucleus varied from 5 to 33.6 msec (14.83 +/- 1.77 msec) and of the mediodorsal nucleus from 3.5 to 44.8 msec (18.03 +/- 2.5 msec). A high degree of convergence of reticular and somatovisceral signals on neurons of the centromedian nucleus (52.83%) and mediodorsal nucleus (53.5%) was found. An inhibitory type of interaction of central and peripheral influences was established.

Convergence and interaction of somatic and visceral impulsation on neurons of the ventral posterolateral thalamic nucleus.

Acute experiments on anesthetized and immobilized cats using extracellular derivation of neuronal responses and field potentials demonstrated the predominant localization of somatic (radial nerve) responses in the mediocentral and of visceral (splanchnic nerve) responses in the centrolateral regions of the ventral posterolateral thalamic nucleus. Both similarities and differences were found in patterns of neuronal responses to peripheral stimuli of different types. A quite high degree of convergence of somato-visceral impulsation was found in the central part of the nucleus compared with its medial and lateral regions. Predominance of comparatively long-latency convergent neurons over short-latency was observed. The inhibitory character of somatovisceral interaction and the more effective inhibitory influence of conditioning stimulation of the radial nerve on test-response of splanchnic origin were demonstrated.