Taming the exoscope: a one-year prospective laboratory training study.

PURPOSE: Digital 3D exoscopes have been recently introduced as an alternative to a surgical microscope in microneurosurgery. We designed a laboratory training program to facilitate and measure the transition from microscope to exoscope. Our aim was to observe the effect of a one-year active training on microsurgical skills with the exoscope by repeating a standardized test task at several time points during the training program. METHODS: Two board-certified neurosurgeons with no previous exoscope experience performed the same test tasks in February, July, and November during a 12-month period. In between the test tasks, both participants worked with the exoscope in the laboratory and assisted during clinical surgeries on daily basis. Each of the test segments consisted of repeating the same task 10 times during one week. Altogether, 60 test tasks were performed, 30 each. The test task consisted of dissecting and harvesting the ulnar and radial arteries of the second segment of a chicken wing using an exoscope (Aesculap AEOS). Each dissection was recorded on video and analyzed by two independent evaluators. We measured the time required to complete the task as well as several metrics for evaluating the manual skills of the dissection and handling of the exoscope system. RESULT: There was a clear reduction in dissection time between the first and the last session, mean 34 min (SD 5.96) vs. 26 min (SD 8.69), respectively. At the end of the training, both neurosurgeons used the exoscope more efficiently utilizing more available options of the device. There was correlation between the dissection time and several of the factors we used for evaluating the work flow: staying in focus, zoom control, reduction of unnecessary movements or repetitive manual motions, manipulation technique of the vessel under dissection, handling of the instruments, and using them for multiple dissection purposes (stretching, cutting, and splitting). CONCLUSION: Continuous, dedicated long-term training program is effective for microsurgical skill development when switching from a microscope to an exoscope. With practice, the micromotor movements become more efficient and the use of microinstruments more versatile.

Parasagittal meningeal hemangiopericytoma/solitary fibrous tumor: Two case reports and a literature review.

Background: Solitary fibrous tumor/meningeal hemangiopericytoma (SFT/M-HPC) is a rare neoplasm which accounts for around 1% of the intracranial masses. This pathology has a high risk for recurrence and metastasis to distant locations such as the liver, lungs, and bones. Precise diagnosis necessitates detailed histopathological examination. Case Description: We present two case reports of SFT/M-HPC. The first case is a 44-year-old female who presented with headache, nausea, vomiting, and frontal ataxia for several months. Imaging findings showed a large parasagittal extra-axial mass with compression of the frontal horns of both lateral ventricles. She underwent gross total resection with an uncomplicated postoperative period. The patient had no recurrent tumors or distal metastases in the follow-up period of 5 years. The second case is a 48-year-old male who presented with right-sided hemianopsia and hemiparesis. Computed tomography (CT) scans revealed a large parieto-occipital extra-axial mass with superior sagittal sinus engulfment and dislocation of the interhemispheric fissure. He underwent gross total resection with an uncomplicated postoperative period. Six years later, he presented with right-sided weakness. CT scan showed a multifocal recurrent mass at the previous location. He underwent subtotal resection with an uncomplicated postoperative period. Conclusion: SFT/M-HPC should be considered when presented with a meningioma-like tumor mass on preoperative imaging. Immunohistochemical study is crucial for the correct diagnosis. Strict long-term follow-up examinations and regular magnetic resonance imaging scans are key to preventing the appearance of metastases and large recurrent masses.