Emrah Celtikci, Burak Karaaslan, Alp Özgün Börcek, and Omer Hakan Emmez
During the coronavirus disease 2019 (COVID-19) pandemic, neurosurgeons all around the globe continue to operate in emergency cases using new self-protective measures. Personal protective equipment (PPE) use is recommended in all surgeries. The authors have experienced varying degrees of field of view (FOV) loss under the surgical microscope with different PPE. Herein, they aimed to investigate the effects of different PPE on FOV while using the surgical microscope.
Fifteen neurosurgeons and neurosurgery residents participated in this study. Three kinds of PPE (safety spectacles, blast goggles, and face shields) were tested while using a surgical microscope. FOV was measured using a 12 × 12–cm checkered sheet of paper on which every square had an area of 25 mm2 under the microscope. The surgical microscope was positioned perpendicular to the test paper, and the zoom was fixed. Each participant marked on the test sheet the peripheral borders of their FOV while using different PPE and without wearing any PPE. A one-way repeated-measures ANOVA was performed to determine if there was a significant difference in FOV values with the different PPE.
FOV was significantly different between each PPE (F[3, 42] = 6339.845, p < 0.0005). Post hoc analysis revealed a significant decrease in the FOV from the naked eye (9305.33 ± 406.1 mm2) to blast goggles (2501.91 ± 176.5 mm2) and face shields (92.33 ± 6.4 mm2). There were no significant FOV changes with the safety spectacles (9267.45 ± 410.5 mm2).
While operating under a surgical microscope safety spectacles provide favorable FOVs. Face shields increase the eye piece–pupil distance, which causes a severe reduction in FOV.
Huseyin Biceroglu, Sait Albayram, Sabri Ogullar, Zehra Isik Hasiloglu, Hakan Selcuk, Odhan Yuksel, Burak Karaaslan, Can Yildiz, and Adem Kiris
For nearly 100 years it has been believed that the main reabsorption of CSF occurs in arachnoid projections into the superior sagittal sinus, but a significant number of experiments and cases conflict with this hypothesis. According to recently published studies, CSF is permanently produced and absorbed in the whole CSF system. Clusters of arachnoidal villi, which are speculated to have a role in the reabsorption of CSF, have recently been revealed in the dorsal root of the spinal nerves. Huge absorptive surface areas of microvessels have been suggested to serve a putative role in reabsorption. The authors' aim was to observe direct venous connections between the subarachnoid space and the perispinal veins.
Eleven adult (6 months old) New Zealand white male rabbits weighing approximately 3.0 kg each were used in this experiment. After obtaining precontrast MR cisternography images, subarachnoid access was gained percutaneously via a cisternal approach by using a 20-gauge intravenous indwelling cannula. One rabbit died as a result of brainstem trauma during percutaneous cannulation before contrast administration, but contrast agent was still injected to see the possible MR imaging results of spinal CSF reabsorption after death. Magnetic resonance imaging was performed at 15, 60, 120, and 180 minutes after the administration of contrast agent. After intramuscular injections of anesthetic, 2 rabbits died 120 and 150 minutes after contrast injection, but the MR imaging study at 180 minutes after contrast injection was still performed.
Direct connections between the subarachnoid space and the perispinal veins were observed in all rabbits during serial MR cisternography. The enhancement power was not affected by the amount of injected contrast agent or by cervical or lumbar penetration but was increased at higher contrast concentrations or upon seizure (physical activity).
Extracranial reabsorption of CSF has been finally proved with direct radiological confirmation of spinal venous reabsorption of CSF using serial MR cisternography. The authors believe that this study can help to develop a more accurate model of CSF dynamics, which will allow understanding of many CSF-related diseases, as well as the development of new strategies for treatment.