Intraoperative neurophysiological monitoring in patients with delayed cerebral ischemia after clipping of ruptured arterial aneurysms

Abstract

Aim. Research of significant changes in parameters (SCP) by intraoperative neurophysiological monitoring (IONM) during clipping of ruptured cerebral aneurysms in patients with delayed cerebral ischemia (DCI) in the postoperative period.Materials and methods. The study included 16 patients, 7 (43.8 %) men and 9 (56.2 %) women, aged 51.1 ± 9.3 years, who underwent clipping of ruptured cerebral aneurysms for the period 2016–2021, in which the neurological deficit (ND) remained at the preoperative level on the first postoperative day, but increased by the end of hospitalization. In order to study the factors leading to the development of DCI, 2 groups were identified with transient SCP according to IONM: with the development of DCI – 7 patients out of the above 16 patients, including 3 men (42.9 %) and 4 women (57.1 %), aged 49.6 ± 8.5 years; and control group – 19 patients, including 9 men (47.4 %) and 10 women (52.6 %), aged 46.2 ± 10.9 years, in whom ND did not increase on the first postoperative day and by the time of discharge. The groups did not differ significantly in age, sex, aneurysm location, rupture period, and baseline ND.Results. In patients with DCI, in 9 cases (56.2 %), during the operation, SCP from the side of somatosensory evoked potentials (SSEP) and transcranial motor evoked potentials (TcMEP) was not registered, in 7 cases (43.8 %) transient SCP was registered, of which 3 patients (42.8 %) had TcMEP and SSEP, in 2 patients (28.6 %) – only TcMEP and in 2 patients (28.6 %) – only SSEP. In the control group, transient SCR of TcMEPs and SSEPs were registered in 4 patients (21.6 %), only TcMEPs – in 9 patients (47.4 %), only SSEPs – in 6 patients (31.6 %). When comparing two groups of patients with transient SCR (DCI‑group and control group), a statistically significant predominance was revealed in the first group of patients with severity 3 according to the Hunt–Hess scale (42.9 % vs 5.2 %), while in the second group patients of severity 1 and 2 prevailed (94.8 % vs 57.2 %) (p <0.05). When analyzing the data of ultrasonic duplex scanning of extra- and intracranial arteries in both groups, a statistically significant increase in peak systolic blood flow velocity in the middle cerebral artery was revealed (in the group with DCI before surgery – 100 (80–139) cm/s, after surgery – 175 (139–278) cm/s (p = 0.001), in the control group before surgery – 100 (100–118) cm/s, after surgery – 150 (116–194) cm/s (p = 0.0001)), as well as the Lindegaard index (in the group with DCI before surgery – 2.5 ± 0.7, after surgery – 3.5 ± 1.1 (p = 0.01), in the control group before surgery – 2.1 ± 0.3, after surgery 2.9 ± 1.1 (p = 0.0002)), but the differences between the groups were not statistically significant (p = 0.092).Conclusion. At this stage, it cannot be unequivocally stated that transient SCP according to IONM may be one of the risk factors for the development of DCI after clipping of ruptured cerebral aneurysms. However, patients with transient SCR according to IONM, whose severity at admission is estimated at 3 points on the Hunt–Hess scale, are statistically significantly more likely to develop DCI.