influence of anesthesia type on intraocular pressure during spine surgery in prone position

The aim was to examine intraocular pressure (IOP) during lumbar spine surgery in PP under general vs spinal anesthesia and to compare it with volunteers in PP. Materials and methods: We performed randomized prospective single institutional trial. Patients were operated in PP with fixation of 1-2 spinal segments. Patients of group I (n = 30) were operated under SA, group 2A (n = 25) - under TIVA (total intravenous anesthesia) with 45° head rotation (left eye was located lower, than right eye), group 2B (n=25) - under TIVA with no head rotation (both eyes were located on the same level). IOP was measured with Maklakov method before and after surgery. Volunteers (n = 20) were examined before and 90 minutes after lying in PP with 45° head rotation. Results: In all patients and volunteers after lying in PP, we found that IOP have increased. In SA patients and in TIVA patients with no head rotation there was no difference between eyes. The most significant raise of IOP was found in the dependent eye of IIA group patients: it was higher than in volunteers and I group patients (p < 0.01), and IIB group patients (p < 0.05). In SA patients there was no difference in IOP comparing to volunteers. Conclusions: IOP increased in PP in healthy people and patients under anesthesia (SA and TIVA). IOP in SA patients did not differ from volunteers. IOP increased superiorly in the dependent eye in TIVA patients.