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Objective: In image-guided neurosurgery, co-registered preoperative anatomical, functional, and diffusion tensor imaging can be used to facilitate a safe resection of brain tumors in eloquent areas of the brain. However, the brain deforms during surgery, particularly in the presence of tumor resection. Non-Rigid Registration (NRR) of the preoperative image data can be used to create a registered image that captures the deformation in the intraoperative image while maintaining the quality of the preoperative image. Using clinical data, this paper reports the results of a comparison of the accuracy and performance among several non-rigid registration methods for handling brain deformation. A new adaptive method that automatically removes mesh elements in the area of the resected tumor, thereby handling deformation in the presence of resection is presented. To improve the user experience, we also present a new way of using mixed reality with ultrasound, MRI, and CT.Materials and methods: This study focuses on 30 glioma surgeries performed at two different hospitals, many of which involved the resection of significant tumor volumes. An Adaptive Physics-Based Non-Rigid Registration method (A-PBNRR) registers preoperative and intraoperative MRI for each patient. The results are compared with three other readily available registration methods: a rigid registration implemented in 3D Slicer v4.4.0; a B-Spline non-rigid registration implemented in 3D Slicer v4.4.0; and PBNRR implemented in ITKv4.7.0, upon which A-PBNRR was based. Three measures were employed to facilitate a comprehensive evaluation of the registration accuracy: (i) visual assessment, (ii) a Hausdorff Distance-based metric, and (iii) a landmark-based approach using anatomical points identified by a neurosurgeon.Results: The A-PBNRR using multi-tissue mesh adaptation improved the accuracy of deformable registration by more than five times compared to rigid and traditional physics based non-rigid registration, and four times compared to B-Spline interpolation methods which are part of ITK and 3D Slicer. Performance analysis showed that A-PBNRR could be applied, on average, in <2 min, achieving desirable speed for use in a clinical setting.Conclusions: The A-PBNRR method performed significantly better than other readily available registration methods at modeling deformation in the presence of resection. Both the registration accuracy and performance proved sufficient to be of clinical value in the operating room. A-PBNRR, coupled with the mixed reality system, presents a powerful and affordable solution compared to current neuronavigation systems.

Pituitary adenoma surgery has evolved rapidly in recent decades, changing clinical practice markedly and raising new challenges. There is no current consensus or guidelines for perioperative care that includes possible complication management. This study aims to determine current practice across European neurosurgical centers. We created a list of eligible departments performing pituitary adenoma surgery based on cooperation with EANS, Νational neurosurgical societies, and personal communication with local neurosurgeons. We contacted the chairpersons from each department and asked them (or another responsible neurosurgeon) to ll out the survey. The survey consisted of 58 questions. For further analysis, departments were divided into subgroups: "academic"/"non-academic center", "highvolume"/"low-volume", "mainly endoscopic"/"mainly microscopic"/"mixed practise" and by geographical regions. Data from 254 departments from 34 countries were obtained. The average time to complete the survey was 18 min. Notably, the endoscopic approach is the predominant surgical approach in Europe, used in 56.8% of the centers. In routine cases without intraoperative cerebrospinal uid leak, high-volume centres are less pedantic with sellar closure when compared with low-volume centres. On the other hand, when a postoperative cerebrospinal uid leak occurs, high-volume centres are more active and indicate early reoperation. Less than 15% of the participating centres perform early postoperative MRI scans.Marked variation was noted among different groups of respondents and some contentious issues are discussed. Such information can encourage useful debate about the reasons for the variations seen and perhaps help develop standardised protocols to improve patient outcomes. A future research focus is to compare European results with other regions.

Background: The Full Outline of Unresponsiveness (FOUR) score is a clinical instrument for the assessment of consciousness which is gradually gaining ground in clinical practice, as it incorporates more complete neurological information than the Glasgow Coma Scale (GCS). The main objectives of the current study were the following: (1) translate and cross-culturally adapt the FOUR score into Greek; (2) evaluate its clinimetric properties, including interrater reliability, internal consistency, and construct validity; and (3) evaluate the reliability of assessments among health care professionals with different levels of experience and training. Methods:The FOUR score was initially translated into Greek. Next, patients with neurosurgical pathologies in need of consciousness monitoring were independently assessed with the GCS and FOUR score within one hour by four raters who had different levels of experience and training (two board-certified neurosurgeons, a neurosurgery resident, and a registered nurse). Interrater reliability, internal consistency, and construct validity were evaluated for the scales using weighted Cohen's κ (κ w ) and intraclass correlation coefficients (ICC), Cronbach's α and Spearman's ρ values, respectively. Results: A total of 408 assessments were performed for 99 patients. The interrater reliability was excellent for both the FOUR score (ICC = 0.941) and GCS (ICC = 0.936). The values of κ w exceeded 0.90 for all pairs, suggesting that the FOUR score can be reliably applied by raters with varying experience. Among the scales' components, FOUR score's brainstem and respiratory items showed the lowest, yet high enough (κ w > 0.60), level of agreement. The interrater reliability remained excellent (κ w > 0.85, ICC > 0.90) for all diagnosis and age groups, with a trend toward higher FOUR score values in the most severe cases (ICC = 0.813 vs. 0.723). Both the FOUR score and GCS showed high internal consistency (Cronbach's α > 0.70 for all occasions). The FOUR score correlated strongly with GCS (Spearman's ρ > 0.90 for all raters), suggesting high construct validity.

Key Clinical MessageWe report a case of spinal epidural hematoma (SEH) preceded by diagnostic lumbar puncture (LP) in a 5-year-old boy with acute lymphoblastic leukemia. MRI confirmed the presence of SEH between T7 and L5 levels, but the patient showed fast recovery during the next hours and conservative management was elected.

Objective. Pituitary adenoma surgery has evolved rapidly in recent decades. This study aims to determine current practice across a wide range of European neurosurgical centers. Methods. A list of eligible departments performing pituitary adenoma surgery was created. The survey consisted of 58 questions. For analysis, the departments were divided into four subgroups: academic/nonacademic, high-volume/low-volume, “mainly endoscopic/mainly microscopic practice,” and geographical regions. Results. Data from 254 departments from 34 countries were obtained. In 108 centers (42.5%), <30 pituitary adenomas were operated per year. Twenty (7.9%) centers performed >100 adenoma surgeries per year. Number of neurosurgeons performing endonasal surgeries are as follows: 1 in 24.9% of centers and 2 in 49.8% of centers. All residents assisted endonasal surgeries in 126 centers (49.8%). In 28 centers (21.1%), all residents performed endonasal surgery under supervision during residency. In 141 centers (56.8%), the endoscopic approach was used in >90% of the surgeries. Regular pituitary board (either weekly or once a month) meetings were held in 147 centers (56.3%). Nonfunctioning adenomas represent >70% of pituitary caseload in 149 centers (58.7%). Conclusions. In our survey, most centers perform less than 100 surgeries for pituitary adenomas. In most centers, pituitary surgeries are performed by one or two neurosurgeons. Residents have a limited exposure to this type of surgery, and the formal pituitary board is not a standard. Nonfunctioning adenomas make up most of surgically treated adenomas. This study can serve as a benchmark for further analyses of pituitary adenoma centers in Europe.

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Hormone-secreting adenomas are treated in many neurosurgical centers within Europe. The goal of the survey is to understand variance in practice management of pituitary tumors amongst neurosurgical centers. A list of departments performing pituitary surgery was created. The survey consisted of 58 questions. This study focuses on neurosurgical care of hormone-secreting adenomas. For analysis, the departments were divided into four subgroups: academic/non-academic, high-volume/low-volume, “mainly endoscopic/mainly microscopic practice” and geographical regions. Data from 254 departments from 34 countries were obtained. Most centers surgically treat 1–5 hormone-secreting adenomas per year. In prolactinomas this is the case in 194 centers, (76.4%), in GH-secreting adenomas: 133 centers, (52.4%), ACTH-secreting adenomas: 172 centers, (69.8%). Surgery as a primary treatment of prolactinomas is considered in 64 centers (25.2%). In 47 centers (18.8%), GH-secreting microadenomas are often treated pharmacologically first. Debulking surgery for an invasive GH-secreting adenoma in which hormonal remission is not a realistic goal of the surgery and the patient has no visual deficit surgery is always or mostly indicated in 156 centers (62.9%). Routine postoperative hydrocortisone replacement therapy is administered in 147 centers (58.6%). Our survey shows that in most centers, few hormone-secreting adenomas are treated per year. In about 25% of the centers, prolactinoma surgery may be regarded as first-line treatment; in about 20% of the centers, medical treatment is the first-line treatment for GH-secreting adenomas. Pretreatment for ACTH-secreting adenomas is routinely used in 21% of centers. This survey may serve as plea for neurosurgical care centralization of hormone-secreting adenomas.