Immersive virtual reality as a surgical training tool: A cohort study.

Background: Few studies have studied the efficacy of using immersive virtual reality (iVR) to teach surgical skills, especially by using real-world iVR recordings rather than simulations. This study aimed to investigate whether viewing 360° iVR instructional recordings produces greater improvements in basic suturing skills of students without prior medical training, beyond traditional methods like reading written manuals or watching 2D instructional videos. Materials and methods: This was a partially blinded randomized cohort study. 44 pre-university students (aged 17) were randomized equally to either the written instruction manual, 2D instructional video, or iVR recordings. All students first watched a silent 2D demonstration video of the suturing task, before attempting to place three simple interrupted sutures on a piece of meat as a baseline. The time taken for the first attempt was recorded. Students were then given an hour to train using their allocated modality. They attempted the suturing task again, and timings were re-recorded. Four blinded surgically-trained judges independently assessed the quality of the stitches placed both pre and post-intervention. One-way analysis of variance tests (ANOVAs) and independent two-sample t-tests were used to determine the effect of training modality on improvements in suturing scores and time taken to complete suturing from pre to post-training. Results: For suturing scores, the iVR group showed significantly larger score improvements than the Written Manual group (p = 0.031, Cohen's D = 0.92), while this iVR advantage was less pronounced when compared with the 2D Video group (p = 0.16, Cohen's D = 0.65). Similarly for time taken to complete suturing, the iVR group had significantly larger time improvements than the Written Manual group (p = 0.045), although this difference was less robust compared to the 2D Instructional Video group (p = 0.34). Conclusion: This study demonstrates that iVR training using real-world 360° instructional recordings produced significantly greater training gains in suturing scores and efficiency compared to reading written text. iVR training also led to larger training gains in both outcome measures than viewing 2D instructional videos, although the differences between them did not reach statistical significance.

The Impact of Multimorbidity Burden, Frailty Risk Scoring, and 3-Directional Morphological Indices vs. Testing for CSF Responsiveness in Normal Pressure Hydrocephalus.

Objective: Multimorbidity burden across disease cohorts and variations in clinico-radiographic presentations within normal pressure hydrocephalus (NPH) confound its diagnosis, and the assessment of its amenability to interventions. We hypothesized that novel imaging techniques such as 3-directional linear morphological indices could help in distinguishing between hydrocephalus vs. non-hydrocephalus and correlate with responsiveness to external lumbar drainage (CSF responsiveness) within NPH subtypes. Methodology: Twenty-one participants with NPH were recruited and age-matched to 21 patients with Alzheimer's Disease (AD) and 21 healthy controls (HC) selected from the Alzheimer's Disease Neuroimaging Initiative (ADNI) database. Patients with NPH underwent testing via the NPH programme with external lumbar drainage (ELD); pre- and post-ELD MRI scans were obtained. The modified Frailty Index (mFI-11) was used to stratify the NPH cohort, including Classic and Complex subtypes, by their comorbidity and frailty risks. The quantitative imaging network tool 3D Slicer was used to derive traditional 2-dimensional (2d) linear measures; Evans Index (EI), Bicaudate Index (BCI) and Callosal Angle (CA), along with novel 3-directional (3d) linear measures; z-Evans Index and Brain per Ventricle Ratio (BVR). 3-Dimensional (3D) ventricular volumetry was performed as an independent correlate of ventriculomegaly to CSF responsiveness. Results: Mean age for study participants was 71.14 ± 6.3 years (18, 85.7% males). The majority (15/21, 71.4%) of participants with NPH comprised the Complex subtype (overlay from vascular risk burden and AD); 12/21 (57.1%) were Non-Responders to ELD. Frailty alone was insufficient in distinguishing between NPH subtypes. By contrast, 3d linear measures distinguished NPH from both AD and HC cohorts, but also correlated to CSF responsiveness. The z-Evans Index was the most sensitive volumetric measure of CSF responsiveness (p = 0.012). Changes in 3d morphological indices across timepoints distinguished between Responders vs. Non-Responders to lumbar testing. There was a significant reduction of indices, only in Non-Responders and across multiple measures (z-Evans Index; p = 0.001, BVR at PC; p = 0.024). This was due to a significant decrease in ventricular measurement (p = 0.005) that correlated to independent 3D volumetry (p = 0.008). Conclusion. In the context of multimorbidity burden, frailty risks and overlay from neurodegenerative disease, 3d morphological indices demonstrated utility in distinguishing hydrocephalus vs. non-hydrocephalus and degree of CSF responsiveness. Further work may support the characterization of patients with Complex NPH who would best benefit from the risks of interventions.

Decompressive craniectomy for internal carotid artery and middle carotid artery infarctions: a long-term comparative outcome study.

OBJECTIVE: Malignant internal carotid artery (ICA) infarction is an entirely different disease entity when compared with middle cerebral artery (MCA) infarction. Because of an increased area of infarction, it is assumed to have a poorer prognosis; however, this has never been adequately investigated. Decompressive craniectomy (DC) for malignant MCA infarction has been shown to improve mortality rates in several randomized controlled trials. Conversely, aggressive surgical decompression for ICA infarction has not been recommended. The authors sought to compare the functional outcomes and survival between patients with ICA infarctions and those with MCA infarctions after DC in the largest series to date to investigate this assumption. METHODS: A multicenter retrospective review of 154 consecutive DCs for large territory cerebral infarctions performed from 2005 to 2020 were analyzed. Patients were divided into ICA and MCA groups depending on the territory of infarction. Variables, including age, sex, medical comorbidities, laterality of the infarction, preoperative neurological status, primary stroke treatment, and the time from stroke onset to DC, were recorded. Univariable and multivariable analyses were performed for the clinical exposures for functional outcomes (modified Rankin Scale [mRS] score) on discharge and at the 1- and 6-month follow-ups, and for mortality, both inpatient and at the 1-year follow-up. A favorable mRS score was defined as 0-2. RESULTS: There were 67 patients (43.5%) and 87 patients (56.5%) in the ICA and MCA groups, respectively. Univariable analysis showed that the ICA group had a comparably favorable mRS (OR 0.15 [95% CI 0.18-1.21], p = 0.077). Inpatient mortality (OR 1.79 [95% CI 0.79-4.03], p = 0.16) and 1-year mortality (OR 2.07 [95% CI 0.98-4.37], p = 0.054) were comparable between the groups. After adjustment, a favorable mRS score at 6 months (OR 0.17 [95% CI 0.018-1.59], p = 0.12), inpatient mortality (OR 1.02 [95% CI 0.29-3.57], p = 0.97), and 1-year mortality (OR 0.94 [95% CI 0.41-2.69], p = 0.88) were similar in both groups. The overall survival, plotted using the Cox proportional hazard regression, did not show a significant difference between the ICA and MCA groups (HR 0.581). CONCLUSIONS: Unlike previous smaller studies, this study found that patients with malignant ICA infarction had a functional outcome and survival that was similar to those with MCA infarction after DC. Therefore, DC can be offered for malignant ICA infarction for life-saving purposes with limited functional recovery.

The Seow Operative Score (SOS) as a decision-making adjunct for paediatric Chiari I malformation: a preliminary study.

PURPOSE: The natural history of Chiari I malformation (C1M) in the paediatric population is poorly understood. There are conflicting reports with regards to surgical indications, operative techniques and peri-operative prognostic indicators. In this paper, we report our institutional experience in the management of paediatric C1M. METHODS: The workflow process which includes preferred imaging modalities, surgical techniques and indications for intervention is discussed. In particular, we describe one of our current projects-an in-house designed Seow Operative Score (SOS) as a feasibility scoring system for neurosurgical intervention in our local cohort of paediatric C1M patients. RESULTS: In our series, we have 2 groups: 10 non-operated patients versus 19 operated patients. In the non-operated group, the majority of patients had a SOS of 0 to 1. One patient had a score of 2.5 and was kept under close surveillance. Follow-up imaging demonstrated resolution of the cerebellar herniation and intraspinal syrinx. In the operated group, 17 patients had a SOS of 3 or more. Two patients had a SOS of 2. For these 2, 1 developed progressive symptoms, and the other had an extensive cervico-thoracic syrinx. Decision was made for surgery after a period of surveillance. CONCLUSIONS: In this paper, we report our institutional experience in managing paediatric C1M and, at the same time, highlight salient points of our practices. Meanwhile, we advocate collective global efforts and in-depth research for better disease understanding of this challenging condition.

Phospholipase C-η2 is required for retinoic acid-stimulated neurite growth.

Phospholipase C-η2 is a recently identified phospholipase C (PLC) implicated in the regulation of neuronal differentiation/maturation. PLCη2 activity is triggered by intracellular calcium mobilization and likely serves to amplify Ca²âº signals by stimulating further Ca²âº release from Ins(1,4,5)P3-sensitive stores. The role of PLCη2 in neuritogenesis was assessed during retinoic acid (RA)-induced Neuro2A cell differentiation. PLCη2 expression increased two-fold during a 4-day differentiation period. Stable expression of PLCη2-targetted shRNA led to a decrease in the number of differentiated cells and total length of neurites following RA-treatment. Furthermore, RA response element activation was perturbed by PLCη2 knockdown. Using a bacterial two-hybrid screen, we identified LIM domain kinase 1 (LIMK1) as a putative interaction partner of PLCη2. Immunostaining of PLCη2 revealed significant co-localization with LIMK1 in the nucleus and growing neurites in Neuro2A cells. RA-induced phosphorylation of LIMK1 and cAMP-responsive element-binding protein was reduced in PLCη2 knock-down cells. The phosphoinositide-binding properties of the PLCη2 PH domain, assessed using a FRET-based assay, revealed this domain to possess a high affinity toward PtdIns(3,4,5)P3. Immunostaining of PLCη2 together with PtdIns(3,4,5)P3 in the Neuro2A cells revealed a high degree of co-localization, indicating that PtdIns(3,4,5)P3 levels in cellular compartments are likely to be important for the spatial control of PLCη2 signaling.