Exoscopy of Detrital Zircons from Niamey Neoproterozoic Sandstones (Eastern Edge of the West African Craton, Southwestern Niger): Interpretation of Detrital Sediments Provenance

This study focuses on exoscopic analyses of detrital zircon grains of Archean and Paleoproterozoic age, contained in the sediments from the Niamey Neoproterozoic sandstones (Niamey region), with a view to confirming the sediments sources already proposed (Kénéma-Man domain for Archean-age zircons and Baoulé Mossi domain for Paleoproterozoic-age zircons). Exoscopic analysis reveals that Archean zircon grains are more corroded, with rounded to sub-rounded shapes, while Paleoproterozoic zircon grains are less corroded and mostly angular in shape. The strong corrosion of Archean zircon grains, implying long-distance transport, is consistent with the remoteness of the Kenema-Man domain which are the source these sediments. The fact that the Paleoproterozoic zircon grains show little or no wear implies a proximal source of sediments, corresponding to the Baoulé Mossi domain.

Right gyrus cinguli low-grade astrocytoma recurrence removed through a contralateral transfalcine approach with a 4K-3D exoscope

Background Brain tumor surgery has been using operative microscope for years.Recently,thanks to developments in surgical technology with procedures performed on head-up displays,exoscopes have been introduced as an alternative to microscopic vision.Case presentation We present a case of a 46-year-old patient with a low-grade glioma recurrence of the right gyrus cinguli removed with a contralateral transfalcine approach using an exoscope(ORBEYE 4K-three-dimensional(3D)exoscope,Sony Olympus Medical Solutions Inc.,Tokyo,Japan).The operating room setup for this approach is illustrated.During the procedure,the surgeon was seated with head and back in an upright position,while the camera was aligned with the surgical corridor.The exoscope provided detailed,high-quality 4K-3D images of the anatomical structures and optimal depth perception,making surgery accurate and precise.At the end of the resection,an intraoperative MRI scan showed complete removal of the lesion.The patient was discharged on postoperative day 4 with an excellent performance on neuropsychological examination.Conclusions In this clinical case the contralateral approach was favorable because the glioma was located close to the midline and because it offered a straight path to the tumor,minimizing retraction on the brain.The exoscope provided the surgeon with important advantages in terms of anatomical visualization and ergonomics during the entire procedure.

Use of a compact high-definition two-dimensional exoscope in surgical treatment of large vestibular schwannoma

Background::Extra-corporeal video telescope operating monitor system provides a necessary instrument to perform high-precision neurosurgical procedures that could substitute or supplement the traditional surgical microscope.The present study was designed to evaluate a compact high-definition two-dimensional exoscope system for assisting in surgical removal of large vestibular schwannoma(VS),as an alternative to a binocular surgical microscope.Methods::Patients with Koos grade 3 and grade 4 VS undergoing surgery were enrolled in this prospective cohort study between January 2013 and June 2018.The demographics and tumor characteristics(size,Koos grade,composition[cystic or solid mass])were matched between the two groups of patients.The following outcome measurements were compared between the two groups:duration of surgery,volume of blood loss,extent of tumor resection,number of operating field adjustments,pre-and post-operative facial and cochlear nerve function evaluated at 3 months post-surgery,complications and surgeons’comfortability.Results::A total of 81 patients received tumor resection through the retrosigmoid approach under either an exoscope(cases,n=39)or a surgical microscope(control,n=42).Patients in the two groups had comparable tumor location(P=0.439),Koos grading(P=0.867),and composition(P=0.891).While no significant differences in the duration of surgery(P=0.172),extent of tumor resection(P=0.858),facial function(P=0.838),and hearing ability(P=1.000),patients operated on under an exoscope had less blood loss(P=0.036)and a fewer field adjustments(P<0.001).Both primary and assistant surgeons reported a high level of comfort operating under the exoscope(P=0.001 and P<0.001,respectively).Conclusions::The compact high-definition two-dimensional exoscope system provides a safe and efficient means to assist in removing large VSs,as compared to a surgical microscope.After the acquaintance with a visual perception through a dynamic hint and stereoscopically viewing corresponding to the motion parallax,the exoscope system provided a comfortable,high-resolution visualization without compromising operational efficiency and patient safety.