Subpial corticectomy simulation

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Subpial corticectomy simulation

Subpial corticectomy simulation is a highly specialized procedure that involves recreating the surgical process of a subpial corticectomy in a controlled, virtual, or educational environment. The aim of this simulation can be to enhance surgical skills, train residents, or explore surgical strategies before performing on actual patients.

Objectives of Simulation

– Skill Acquisition: To train neurosurgeons or trainees in performing precise cortical resections.

– Preoperative Planning: To visualize and plan the approach to lesions in eloquent brain areas.

– Patient Safety: To practice techniques in a risk-free environment.

– Understanding Neuroanatomy: To study cortical and subcortical structures in detail.

Tools and Technologies

– 3D Imaging Platforms: Use of advanced imaging technologies like MRI, fMRI, or DTI integrated into surgical simulation software.

– Virtual Reality (VR) Systems: Platforms like VR surgical simulators to recreate the tactile feedback and visual representation of the brain.

– NeuroNavigation Systems: Integrating systems like Medtronic StealthStation or Brainlab for accurate anatomical representation.

– Augmented Reality (AR): Overlaying virtual structures onto real-world models for enhanced surgical guidance.

– Haptic Feedback Devices: To mimic the feel of cutting or coagulating brain tissue.

Simulation Workflow

1. Data Acquisition:

  1. Collect patient-specific imaging data (MRI, CT) for realistic brain modeling.

2. Virtual Environment Setup:

  1. Load imaging data into the simulation software.
  2. Configure tools and settings specific to the procedure.

3. Preoperative Planning:

  1. Identify the target area for corticectomy and any nearby eloquent regions.
  2. Simulate mapping techniques (e.g., motor, sensory cortex).

4. Surgical Simulation:

  1. Practice opening the dura, identifying gyri and sulci, and using subpial dissection techniques.
  2. Simulate use of instruments like suction, bipolar coagulation, and microdissectors.

5. Complication Management:

  1. Train for real-life scenarios like unexpected bleeding, eloquent cortex compromise, or equipment failure.

6. Postoperative Analysis:

  1. Evaluate resection accuracy, complication rates, and adherence to surgical plans.

Educational Integration

– Team-Based Training: Incorporate anesthetists, nursing staff, and assistants into simulations to mimic the operating room dynamic.

– Feedback Mechanisms: To evaluate performance, use metrics like accuracy, time taken, and safety.

– Case Reviews: Discuss simulated cases in grand rounds or workshops.

Future Directions

– AI Integration: Use AI to guide surgical decision-making based on simulation performance.

– Remote Simulation Platforms: Allow surgeons worldwide to train collaboratively in a shared virtual space.

– Personalized Simulations: Tailor models to patient-specific anatomy and pathology for preoperative rehearsals.

Subpial corticectomy involving complete lesion resection while preserving pial membranes and avoiding injury to adjacent normal tissues is an essential bimanual task necessary for neurosurgical trainees to master. Almansouri et al. sought to develop an ex vivo calf brain corticectomy simulation model with continuous assessment of neurosurgical instruments movement during the simulation. A case series study of skilled participants was performed to assess face and content validity to gain insights into the utility of this training platform, along with determining if skilled and less skilled participants had statistical differences in validity assessment.

An ex vivo calf brain simulation model was developed in which trainees performed a subpial corticectomy of three defined areas. A case series study assessed the face and content validity of the model using 7-point Likert scale questionnaires.

Twelve skilled and 11 less skilled participants were included in this investigation. Overall median scores of 6.0 (range 4.0-6.0) for face validity and 6.0 (range 3.5-7.0) for content validity were determined on the 7-point Likert scale, with no statistical differences between skilled and less skilled groups identified.

A novel ex vivo calf brain simulator was developed to replicate the subpial resection procedure and demonstrated face and content validity 1)

Almansouri et al.’s study represent a valuable contribution to neurosurgical training, offering a novel approach to simulating subpial corticectomy. While the model demonstrates face and content validity, further research is needed to establish its broader applicability and impact on neurosurgical education. Incorporating additional validation metrics and expanding the study’s scope could significantly enhance the simulator’s utility as a training tool.

Santos et al. describe a cadaveric model simulating the resection of a temporo-insular low-grade glioma. Klingler method technique was used to fix the cadaver head before injecting red and blue colorants for a realistic vascular appearance. The hemisphere was frozen for white matter tract dissection. Tractography and intraoperative eloquent areas were extrapolated from a glioma patient by using a neuronavigation system. Then, a frontotemporal craniotomy was performed through a question mark incision, exposing the inferior temporal gyrus up to the middle frontal gyrus. After cortical anatomic landmark identification, eloquent areas were extrapolated creating a simulated functional cortical map. Then, trans opercular non eloquent frontal and temporal corticectomies were performed, followed by subpial resection. Detailed identification of Sylvian vessels and insular cortex was demonstrated. Anatomic resection limits were exposed, and implicated white matter bundles, uncinate, and fronto-occipital fascicles, were identified running through the temporal isthmus. Finally, a temporo-mesial resection was performed. In summary, this model provides a simple, cost-effective, and very realistic simulation of a trans-opercular approach to the insula, allowing the development of surgical skills needed to treat insular tumors in a safe environment. Besides, the integration of simulated navigation has proven useful in better understanding the complex white matter anatomy involved. Cadaver donation, subject or relatives, includes full consent to publish the images. For this video, no ethics committee approval was needed. Images correspond to a cadaver head donation. Cadaver donation, subject or relatives, includes full consent for any scientific purposes involving the corpse. The consent includes an image or video recording. Regarding the intraoperative surgical video and tractography, the patient gave written consent for scientific divulgation before surgery 2).

This cadaveric-based model, as described by Santos et al., is an exemplary tool for advancing neurosurgical education. Despite some inherent limitations, it provides a robust framework for learning the surgical nuances of temporo-insular tumor resections, fostering both anatomical understanding and technical proficiency in a controlled, ethical, and cost-effective manner.

1)

Almansouri A, Abou Hamdan N, Yilmaz R, Tee T, Pachchigar P, Eskandari M, Agu C, Giglio B, Balasubramaniam N, Bierbrier J, Collins DL, Gueziri HE, Del Maestro RF. Continuous Instrument Tracking in a Cerebral Corticectomy Ex Vivo Calf Brain Simulation Model: Face and Content Validation. Oper Neurosurg (Hagerstown). 2024 Jul 1;27(1):106-113. doi: 10.1227/ons.0000000000001044. Epub 2024 Jan 8. PMID: 39813069.
2)

Santos C, Velasquez C, Esteban J, Fernandez L, Mandonnet E, Duffau H, Martino J. Transopercular Insular Approach, Overcoming the Training Curve Using a Cadaveric Simulation Model: 2-Dimensional Operative Video. Oper Neurosurg (Hagerstown). 2021 Nov 15;21(6):E561-E562. doi: 10.1093/ons/opab342. PMID: 34561696.

Spinal schwannoma

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Spinal schwannoma

J.Sales-Llopis

Neurosurgery Department, General University Hospital Alicante, Spain

Latest Pubmed Articles

Definition

Spinal schwannomas are well-described slow growing benign spinal tumors of the peripheral nervous system, arising from Schwann cells.

Epidemiology

see Spinal schwannoma epidemiology.

Classification

see Spinal Schwannoma Classification.

Associations

The vast majority of spinal schwannomas are solitary and sporadic (95%) 10.

However, there is an association with neurofibromatosis type 2 (NF2). In patients with NF2, almost all spinal nerve root tumors are schwannomas or mixed tumors. In a young adult without the NF2 mutation, the finding of multiple schwannomas may meet the criteria for schwannomatosis.

Pathology

Antoni A and Antoni B tissue.

Clinical features

Patients with nonsyndromic spinal schwannoma usually present to hospital with local pain and neurological deficit that exacerbate over time.

Early symptoms are often radicular.

Neurological deficits develop late.

Tumor may cause radiculopathy, myelopathy, radiculomyelopathy or cauda equina syndrome.

Diagnosis

Spinal schwannoma diagnosis

Differential diagnosis

Spinal Schwannoma differential diagnosis

Treatment

see Spinal schwannoma treatment.

Outcome

Spinal schwannoma recurrence is rare after total excision (except in neurofibromatosis).

The risk for motor deficit is higher for schwannomas than for neurofibromas, for cervical vs. lumbar tumors, and for cervical tumors wiyh extradural extension.

Systematic Review and Meta-Analysis

Alvarez-Crespo et al. conducted a systematic review and meta-analysis under the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A search of bibliographic databases from January 1, 2001, to May 31, 2021, yielded 4489 studies. Twenty-six articles were included in our final qualitative systematic review and quantitative meta-analysis.

Analysis of 2542 adult patients’ data from 26 included studies showed that 53.5% were male, and the mean age ranged from 35.8 to 57.1 years. The most common tumor location was the cervical spine (34.2%), followed by the thoracic spine (26.2%) and the lumbar spine (18.5%). Symptom severity was the most common indicator for surgical treatment, with the most common symptoms being segmental back pain, sensory/motor deficits, and urinary dysfunction. Among all patients analyzed, 93.8% were treated with gross total resection, which was associated with a better prognosis and less chance of recurrence than subtotal resection. The posterior approach was the most common (87.4% of patients). The average operative time was 4.53 hours (95% confidence interval [CI], 3.18-6.48); the average intraoperative blood loss was 451.88 mL (95% CI, 169.60-1203.95). The pooled follow-up duration was 40.6 months (95% CI, 31.04-53.07). The schwannoma recurrence rate was 5.3%. Complications were particularly low and included cerebrospinal fluid leakage, wound infection, and sensory-motor deficits. Most of the patients experienced complete recovery or significant improvement of preoperative neurological deficits and pain symptoms.

The analysis suggests that segmental back pain, sensory/motor deficits, and urinary dysfunction are the most common symptoms of spinal schwannomas. Surgical resection is the treatment of choice with overall good reported outcomes and particularly low complication rates. gross total resection offers the best prognosis with the slightest chance of tumor recurrence and minimal risk of complications 1).

Case series

see Spinal Schwannoma Case Series.

Case reports

see Spinal Schwannoma Case Reports.

1)

Alvarez-Crespo DJ, Conlon M, Kazim SF, Skandalakis GP, Bowers CA, Chhabra K, Tarawneh O, Arbuiso S, Cole KL, Dominguez J, Dicpinigaitis AJ, Vellek J, Thommen R, Bisson EF, Couldwell WT, Cole CD, Schmidt MH. Clinical Characteristics and Surgical Outcomes of 2542 Patients with Spinal Schwannomas: A Systematic Review and Meta-Analysis. World Neurosurg. 2024 Feb;182:165-183.e1. doi: 10.1016/j.wneu.2023.11.090. Epub 2023 Nov 24. PMID: 38006933.

Regorafenib for glioblastoma

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Regorafenib for glioblastoma

J.Sales-Llopis

Neurosurgery Department, General University Hospital Alicante, Spain

Regorafenib, a multi-kinase inhibitor, has emerged as a potential therapeutic option for glioblastoma, particularly in cases where standard treatments such as surgery, radiation, and temozolomide chemotherapy have failed.

Mechanism of Action

Regorafenib targets multiple receptor tyrosine kinases involved in tumor proliferation, angiogenesis, and the tumor microenvironment, including:

VEGFR (Vascular Endothelial Growth Factor Receptors)

PDGFR (Platelet-Derived Growth Factor Receptors)

FGFR (Fibroblast Growth Factor Receptors)

KIT, RET, and BRAF These pathways are often dysregulated in glioblastoma, promoting tumor growth and resistance to standard therapies.

Clinical Evidence

REGOMA Trial (2019): A phase II clinical trial evaluated regorafenib in patients with recurrent glioblastoma:

Results: The study showed an improvement in overall survival (OS) compared to lomustine, a standard second-line therapy. Median OS for regorafenib was 7.4 months versus 5.6 months for lomustine. Implications: This result demonstrated the potential of regorafenib as a viable treatment option in recurrent settings. Ongoing Studies:

Further trials (e.g., phase III) are assessing its safety, efficacy, and potential biomarkers for predicting response. Studies are exploring combination therapies, such as regorafenib with immunotherapy, to overcome resistance mechanisms.

Potential Benefits

Angiogenesis Inhibition: Glioblastoma’s hallmark feature is its high vascularity, making anti-angiogenic therapy a promising strategy. Tumor Microenvironment Modulation: Regorafenib can alter the tumor’s supportive environment, potentially enhancing the efficacy of other treatments. Side Effects Regorafenib is associated with several adverse effects that require careful management, including:

Hypertension Hand-foot skin reactions Fatigue Diarrhea Hepatotoxicity Future Directions Biomarker Development: Identifying patients who would benefit most from regorafenib based on genetic and molecular tumor profiles. Combination Therapies: Combining regorafenib with checkpoint inhibitors, radiotherapy, or other targeted agents. Optimization of Dosing: Balancing efficacy with tolerability, particularly in patients with fragile health due to glioblastoma.

Meta-analysis of randomized controlled clinical trials

A meta-analysis, based on searches in PubMed and Web Of Science, evaluated 12 randomized controlled trials (RCTs) examining PKIs in patients with newly diagnosed or recurrent GBM. Pooled analysis of shared clinical outcomes – progression-free survival (PFS) and overall survival (OS) – revealed a lack of significant improvements with the use of PKIs. In newly diagnosed GBM, no significant differences were observed in median [-1.02 months, 95% confidence interval (CI), -2.37-0.32, p=0.14] and pooled [hazard ratio (HR)=1.13, 95% CI, 0.95-1.35, p=0.17) OS, or in median (0.34 months, 95% CI, -0.9-1.58, p=0.60) and pooled (HR=0.98, 95% CI, 0.76-1.27, p=0.89) PFS, when comparing PKI addition to standard chemo-radiotherapy versus chemo-radiotherapy alone. In recurrent GBM, three different analyses were conducted: PKI versus other treatments, PKI combined with other treatments versus those treatments alone, PKI versus PKI combined with other treatments. Also, across these analyses, no significant clinical benefits were found. For instance, when comparing PKI treatment with other treatments, median OS and PFS showed no significant difference (-0.78 months, 95% CI, -2.12-0.55, p=0.25; -0.23 months, 95% CI, -0.79-0.34, p=0.43, respectively), and similar non-significant results were observed in the pooled analyses (OS: HR=0.89, 95% CI, 0.59-1.32, p=0.55; PFS: HR=0.83, 95% CI, 0.63-1.11, p=0.21). Despite these overall negative findings, some data indicate improved clinical outcomes in a subset of GBM patients treated with certain PKIs (i.e., regorafenib) and encourage further research to identify PKIs with better blood-brain barrier penetration and lower risk for resistance development 1)

This meta-analysis underscores the limited efficacy of current PKIs in GBM, despite rigorous methodological approaches. While the findings are largely negative, the identification of potential benefits in specific patient subsets offers a pathway for refining PKI therapy. Future research should prioritize biomarker-driven trials, focus on agents with enhanced BBB penetration, and explore novel combination strategies. The ultimate challenge lies in overcoming the heterogeneity and treatment resistance characteristic of GBM, which remain formidable barriers to improving patient outcomes.

Systematic Reviews

Schettini et al. conducted a systematic review and Bayesian trial-level network metaanalysis (NMA) to identify the regimens associated with the best outcomes. The primary endpoint was overall survival (OS). Secondary endpoints were progression-free survival (PFS) and overall response rates (ORR). They estimated separate treatment rankings based on the surface under the cumulative ranking curve values. Only phase II/III prospective comparative trials were included.

Twenty-four studies (3733 patients and 27 different therapies) were ultimately included. Twenty-three different regimens were compared for OS, 21 for PFS, and 26 for ORR. When taking lomustine as a common comparator, only regorafenib was likely to be significantly superior in terms of OS (hazard ratio: 0.50, 95% credible interval: 0.33-0.75). Regorafenib was significantly superior to other 16 (69.6%) regimens, including NovoTTF-100A, bevacizumab monotherapy, and several bevacizumab-based combinations. Regarding PFS and ORR, no treatment was clearly superior to the others.

This NMA supports regorafenib as one of the best available options for relapsing/refractory glioblastoma. Lomustine, NovoTTF-100A, and bevacizumab emerge as other viable alternative regimens. However, evidence on regorafenib is controversial at best. Moreover, most studies were underpowered, with varying inclusion criteria and primary endpoints, and no longer adapted to the most recent glioblastoma classification. A paradigmatic change in clinical trials’ design for relapsing/refractory glioblastoma and more effective treatments are urgently required 2)

Schettini et al.’s systematic review and Bayesian NMA make an important contribution to understanding the relative efficacy of available therapies for relapsing/refractory GBM, particularly by highlighting regorafenib as a potentially effective option. However, the study is hindered by limitations inherent to the included trials and the analytical framework, including the heterogeneity of studies, underpowered designs, and outdated glioblastoma classifications.

The findings underscore the pressing need for a paradigm shift in GBM clinical trials. Future research should prioritize large, well-powered, multicenter trials incorporating molecularly stratified patient cohorts and harmonized endpoints. Additionally, the exploration of novel therapeutic strategies is critical to advancing the treatment landscape for this devastating disease. While regorafenib appears promising, its clinical utility must be validated in robust, contemporary trials to establish its place in the therapeutic arsenal for GBM.

Retrospective Studies

In a retrospective study, Kebir et al. investigated the efficacy and radiographic tumor growth patterns of regorafenib in recurrent high-grade astrocytoma.

They screened for patients with a high-grade astrocytoma in whom regorafenib was administered for at least 4 weeks. We assessed treatment efficacy in terms of progression-free survival (PFS), overall survival, and adverse events defined by Common Toxicity Criteria (CTC). In addition, radiographic tumor growth patterns were determined at baseline and recurrence.

A total of 6 patients met the eligibility criteria. The number of recurrences prior to regorafenib varied between 2 and 6. Patients were on regorafenib treatment for at least 4 weeks and maximally 14 weeks. Median PFS was 3.5 months and ranged from 2.0 to 4.0 months. Radiographic response was progressive disease in all patients with an objective response rate of 0%. CTC°3 adverse events were observed in all but one patient. The most common radiographic growth pattern was local with no change in growth pattern at recurrence. An infiltrative tumor growth was not induced in any patient.

This retrospective study indicates the very poor performance of regorafenib in recurrent high-grade astrocytoma with a fairly high number of CTC°3 adverse events. In addition, regorafenib does not seem to bear a potential for infiltrative tumor growth promotion 3).

1)

Pinto-Fraga J, García-Chico C, Lista S, Lacal PM, Carpenzano G, Salvati M, Santos-Lozano A, Graziani G, Ceci C. protein kinase inhibitors as Targeted therapy for glioblastoma: A meta-analysis of randomized controlled clinical trials. Pharmacol Res. 2024 Dec 3:107528. doi: 10.1016/j.phrs.2024.107528. Epub ahead of print. PMID: 39637954.
2)

Schettini F, Pineda E, Rocca A, Buché V, Donofrio CA, Mazariegos M, Ferrari B, Tancredi R, Panni S, Cominetti M, Di Somma A, González J, Fioravanti A, Venturini S, Generali D. Identifying the best treatment choice for relapsing/refractory glioblastoma: a systematic review with multiple Bayesian network meta-analyses. Oncologist. 2024 Dec 14:oyae338. doi: 10.1093/oncolo/oyae338. Epub ahead of print. PMID: 39674575.
3)

Kebir S, Rauschenbach L, Radbruch A, Lazaridis L, Schmidt T, Stoppek AK, Pierscianek D, Stuschke M, Forsting M, Sure U, Keyvani K, Kleinschnitz C, Scheffler B, Glas M. Regorafenib in patients with recurrent high-grade astrocytoma. J Cancer Res Clin Oncol. 2019 Apr;145(4):1037-1042. doi: 10.1007/s00432-019-02868-5. Epub 2019 Feb 28. PubMed PMID: 30820715.

DISC care

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DISC care

https://neosurgery.com/project/spine/

Prospective multicenter cohort clinical investigation

The aim of this prospective multicenter cohort clinical investigation was to evaluate the performance and safety of a new hernia blocking system (HBS), implanted after a limited discectomy, for recurrent lumbar disc herniation prevention.

Prospective, multicenter (6 sites), cohort clinical investigation. Thirty patients with a postero-lateral disc herniation between L4-S1 and large annular defects (> 6 mm wide), who underwent a limited discectomy and were treated with a new HBS (DISC care, NEOS Surgery S.L.), were included.

Godino et al. presents details about the investigational device, its surgical technique, intraoperative parameters, and up to 6 months follow-up outcomes. The primary endpoint of the study was to assess the incidence of early symptomatic reherniation. In addition, disc height, leg and back pain (NRS 0-10), Oswestry Disability Index (ODI), quality of life (EQ-5D-5L) and device safety, were evaluated.

Clinicaltrials: gov: NCT04188236; date: 27th November 2019.

Thirty patients (43.3% female, 41.7 ± 10.9 years) were implanted with the device under evaluation in a mean of 16 ± 9.6 min. Six months after surgery, no symptomatic reherniation was detected and disc height was maintained in all patients included. All patients had a significant reduction in leg pain (> 2 points in the NRS), 92.9% improved > 15 points in the ODI and 82.6% significantly improved their quality of life (≥ 12 points in EQ VAS score). No product-related serious adverse events nor reoperations occurred.

The implantation of an HBS is a feasible and safe procedure that prevents early disc herniation recurrence in patients at high risk of reherniation 1).

Strengths of the Study Innovative Focus: The study introduces a new hernia blocking system (HBS), addressing a critical need in spine surgery—preventing recurrent lumbar disc herniation in high-risk patients. This innovation holds promise for improving post-discectomy outcomes.

Study Design: The prospective, multicenter cohort design strengthens the reliability of the findings by incorporating diverse surgical teams and patient demographics across six institutions. Such an approach minimizes potential biases from single-center studies.

Clear Methodology: The inclusion criteria are well-defined, focusing on patients with large annular defects and specific levels of herniation (L4-S1). Additionally, the assessment endpoints are clinically relevant, including reherniation rates, pain (NRS), disability (ODI), and quality of life (EQ-5D-5L).

Safety and Efficacy: The absence of symptomatic reherniation and maintenance of disc height at six months are significant outcomes, especially given the known challenges of recurrent herniation in this patient cohort. The lack of product-related serious adverse events and reoperations further supports the safety of the HBS.

Quantitative Results: Improvements in leg pain (>2 points in NRS), disability (>15 points in ODI for 92.9% of patients), and quality of life (≥12 points in EQ VAS for 82.6% of patients) are clinically significant, offering robust support for the device’s efficacy.

Weaknesses and Limitations Short Follow-Up Period: While the six-month follow-up provides early insights into the device’s safety and efficacy, recurrent disc herniations often occur beyond this timeframe. Longer-term data are essential to confirm durability and sustained benefits.

Small Sample Size: The study includes only 30 patients, limiting the generalizability of its findings. A larger cohort would enhance statistical power and the reliability of conclusions.

Lack of Control Group: The absence of a control group undergoing standard discectomy without HBS implantation makes it challenging to attribute observed benefits solely to the device. Randomized controlled trials (RCTs) are necessary to establish causation.

Subjective Outcome Measures: While NRS, ODI, and EQ-5D-5L are validated tools, they are subjective and may be influenced by patient expectations or placebo effects. Objective functional outcomes or imaging-based metrics could supplement these measures.

Potential Conflicts of Interest: The involvement of NEOS Surgery S.L. in providing the device introduces a potential bias. Transparency about funding and potential conflicts is crucial, though not explicitly addressed in the abstract.

Future Directions Extended Follow-Up: Studies with follow-ups of 2–5 years are needed to evaluate the long-term efficacy and safety of the HBS, particularly in preventing delayed reherniations and preserving disc height.

Larger, Controlled Trials: Conducting RCTs comparing HBS implantation to standard discectomy or other augmentation methods (e.g., annular closure devices) will provide more definitive evidence of its benefits.

Economic Analysis: A cost-effectiveness analysis of the HBS compared to traditional methods would be valuable, given the potential implications for widespread adoption in clinical practice.

Broader Patient Inclusion: Expanding the study to include patients with different types of disc herniations or annular defect sizes may clarify the broader applicability of the device.

Conclusion This study offers promising early evidence supporting the safety and efficacy of the HBS in preventing early recurrent lumbar disc herniation. Despite its limitations, the research sets a strong foundation for further investigation and highlights the potential of this novel device to address a significant clinical challenge. However, longer follow-ups, larger sample sizes, and randomized controlled comparisons are imperative to confirm these findings and establish the HBS as a standard of care in spinal surgery.

1)

Godino O, Fernandez-Carballal C, Català I, Moreno Á, Rimbau JM, Alvarez-Galovich L, Roldan H. A new hernia blocking system to prevent recurrent lumbar disc herniation: surgical technique, intraoperative findings and six-months post-operative outcomes. Eur Spine J. 2024 Dec 8. doi: 10.1007/s00586-024-08595-x. Epub ahead of print. PMID: 39648196.

Hubly Surgical

by

Hubly Surgical

https://hublysurgical.com/

The manual twist drill used for intracranial access represents an opportunity for potential improvement in efficiency, safety, and ease of use. A new generation of portable electrical drills with smart autostop mechanisms, such as the Hubly cranial drill (Hubly Surgical; Lisle, IL), aim to address these opportunities for improvement.

Two patients received EVDs using the portable electrical autostop drill (PEAD): A 54-year-old woman who suffered a postoperative hemorrhage and a 59-year-old woman who presented with early hydrocephalus secondary to hypertensive subarachnoid hemorrhage (SAH). Between both patients, a total of 9 and 2 access attempts were necessary to breach the inner table and visual dura. Access times in both cases, from skin incision to dural puncture, were less than 5 min. There were no apparent complications with the use of the PEAD in either case, and there was excellent placement of the EVD at the foramen of Monroe in both cases.

Oak et al. demonstrate the first successful use of a portable electrical drill with smart autostop in humans. The PEAD has potential to reduce procedure time and human error. Further development of the smart autostop drill may allow for more consistent and safer EVD placement 1).

A cadaveric study was conducted using both drills to perform several burr holes in the fronto-temporo-parietal region of the skull. An evaluation was performed on the number of dura plunges, and complete burr hole success rates were compared.

A total of 174 craniotomies using the HD and 36 burr holes using the ST perforator were performed. Despite significantly exceeding intended drill bit tolerance by multiple uses of a single-use disposable HD, autostop engaged in 100% of the 174 craniotomies and before violating dura in 99.4% of the 174 craniotomies, with the single dura penetration occurring on craniotomy no. 128 after the single-use drill bit had significantly dulled beyond its single-use tolerance. Autostop engaged before dura penetration for 100% of the 36 burr holes drilled with the ST perforator ( P = .610). All the perforations were complete using the HD after resuming drilling. An autostop mechanism in a cranial drill is not commonly available for portable bedside perforators. In the operating room, most use a mechanical method to stop the rotation after losing bone resistance. This new drill uses an electrical mechanism (smart autostop) to stop drilling, making it a single-use cranial drill with advanced features for safety and efficiency at the bedside.

There was no difference in the safety and efficacy of the new cordless electric drill with smart autostop when performing craniotomies compared with a traditional well-established electric cranial perforator with mechanical autostop on a cadaveric model 2)

1)

Oak A, Dardick J, Rusheen A, Materi J, Weingart J, Gonzalez LF, Anderson WS, Mukherjee D. First-in-human experience of a portable electrical drill with smart autostop for bedside external ventricular drain placement. J Clin Neurosci. 2024 Nov 27;131:110941. doi: 10.1016/j.jocn.2024.110941. Epub ahead of print. PMID: 39608055.
2)

Assumpcao de Monaco B, Benjamin CG, Doomi A, Taylor R, Stringfellow CE, Benveniste RJ, Jagid JR, Graciolli Cordeiro J. Safety Analysis of a New Portable Electrical Drill With a Smart Autostop Mechanism for Bedside Cranial Procedures. Oper Neurosurg (Hagerstown). 2023 Oct 1;25(4):311-314. doi: 10.1227/ons.0000000000000804. Epub 2023 Aug 4. PMID: 37543731; PMCID: PMC10468110.

pRESET stent retriever

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pRESET stent retriever

https://www.phenox.net/fileadmin/uploads/produkt_pdf/KIF-0005C_Produktflyer_pREset_01.pdf

The pRESET stent retriever is a modern, self-expanding nitinol device designed for mechanical thrombectomy (MT) in patients with acute ischemic stroke (AIS) due to large vessel occlusion (LVO). This device is part of a growing arsenal of endovascular tools aimed at improving reperfusion outcomes and minimizing neurological damage in stroke patients.

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#### Key Features 1. Self-Expanding Nitinol Design:

  1. Made of nitinol, a material known for its flexibility and memory shape, which aids in navigating tortuous cerebral vessels.
  2. Self-expansion ensures optimal vessel wall apposition and clot engagement.

2. Target Use:

  1. Indicated for cases of AIS caused by LVO in the anterior and posterior circulation.
  2. Designed for deployment through standard microcatheters, compatible with existing endovascular systems.

3. Recanalization Efficiency:

  1. Demonstrates high success rates in recanalizing occluded vessels, both in first-pass and subsequent attempts.
  2. Effective in combination with adjunctive therapies like aspiration.

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#### Clinical Performance A systematic review and meta-analysis (Habibi et al., 2024) evaluated the safety and efficacy of the pRESET device: – Efficacy:

  1. First-pass success: 60% (95% CI: 52%–67%)
  2. Final recanalization success: 90% (95% CI: 83%–95%)
  3. Functional independence (mRS 0-2 at 90 days): 43% (95% CI: 34%–52%)

– Safety:

  1. Overall hemorrhagic complications: 22% (95% CI: 12%–36%)
  2. Parenchymal hemorrhage: 7% (95% CI: 4%–13%)
  3. Subarachnoid hemorrhage: 10% (95% CI: 5%–17%)
  4. Mortality: 18% (95% CI: 12%–25%)

These results suggest that the pRESET device is effective in restoring blood flow and achieving favorable functional outcomes, with complication rates comparable to other stent retrievers.

—

#### Advantages 1. High Recanalization Rates:

  1. Achieves similar or better rates compared to other market leaders like Solitaire or Trevo.

2. Versatility:

  1. Effective across a wide range of occlusion sites and clot characteristics.

3. Ease of Use:

  1. Simplified design enhances maneuverability, reducing procedural complexity.

—

#### Challenges and Considerations 1. Lack of Head-to-Head Comparisons:

  1. Most available data are observational, with few randomized controlled trials directly comparing pRESET to other stent retrievers.

2. Potential for Complications:

  1. Although within acceptable ranges, hemorrhagic complications remain a concern, underscoring the need for careful patient selection.

3. Limited Adoption:

  1. Despite promising results, broader clinical adoption may depend on further validation in diverse populations and healthcare systems.

—

#### Future Directions 1. Comparative Trials:

  1. Randomized controlled trials comparing pRESET with established devices like Solitaire or Trevo could solidify its place in the therapeutic landscape.

2. Real-World Data:

  1. Prospective registry data could provide insights into its performance across different patient demographics and clinical settings.

3. Device Innovation:

  1. Advances in stent retriever technology, such as designs that reduce clot fragmentation or improve safety in fragile vessels, could further enhance outcomes.

—

#### Conclusion The pRESET stent retriever is a promising tool for mechanical thrombectomy in LVO-related strokes, with high efficacy and an acceptable safety profile. While its recanalization and functional outcomes are impressive, additional comparative studies are needed to define its role relative to other devices. As evidence accumulates, pRESET has the potential to become a mainstay in endovascular stroke therapy.

Systematic Review and Meta-Analysis

A systematic review and meta-analysis study conducted based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). The electronic databases of PubMed, Embase, WoS, and Scopus were systematically reviewed from inception to 8 July 2024.

A total of eight studies involving 1163 patients were included. The pooled mortality rate was 18% with a 95% CI of [12%, 25%]. The rates of any hemorrhagic complication, parenchymal hemorrhage, and subarachnoid hemorrhage were 22% with a 95% CI of [12%, 36%], 7% with a 95% CI of [4%, 13%], and 10% with a 95% CI of [5%, 17%], respectively. The rate of favorable functional outcome (modified Rankin Scale 0-2) at 90 days was 43% with a 95% CI of [34%, 52%]. Successful recanalization rates were 60% with a 95% CI of [52%, 67%] after the first pass and 90% with a 95% CI of [83%, 95%] after the final pass. Rescue devices were used in 13% with a 95% CI of [7%, 24%] of cases.

The pRESET stent retriever demonstrates high recanalization rates and reasonable safety outcomes in patients undergoing mechanical thrombectomy for acute ischemic stroke due to large vessel occlusion. Further randomized trials directly comparing pRESET to other stent retrievers are warranted 1).

In a multicenter, prospective, randomized, controlled, open-label, adaptive, noninferiority trial with blinded primary end point evaluation. Between October 2019 and February 2022, multicenter participation occurred across 19 research hospitals and/or universities in the US and 5 in Germany. Patients with LVO stroke were enrolled and included up to 8 hours after symptom onset.

Interventions: Patients underwent 1:1 randomization to thrombectomy with the pRESET or Solitaire stent retriever.

Main outcomes and measures: The primary outcome was the difference in the rate of 90-day functional independence across the 2 devices, using a -12.5% noninferiority margin for the lower bound of the 1-sided 95% CI of the difference between pRESET and Solitaire retrievers.

Results: Of 340 randomized patients, 170 (50.0%) were female, and the median (IQR) age was 73.0 (64.0-82.0) years. The study procedure was completed in 322 of the 340 randomized patients. The primary end point of 90-day functional independence was achieved by 95 patients (54.9%; 95% CI, 48.7-61.1) in the pRESET group and in 96 (57.5%; 95% CI, 51.2-63.8) in the Solitaire group (absolute difference, -2.57%; 95% CI, -11.42 to 6.28). As the lower bound of the 95% CI was greater than -12.5%, the pRESET retriever was deemed noninferior to the Solitaire retriever. The noninferiority of pRESET over Solitaire was also observed in the secondary clinical end point (90-day shift in modified Rankin Scale score) and in both angiographic end points (Expanded Treatment in Cerebral Infarction [eTICI] score of 2b50 or greater within 3 passes: 146 of 173 [84.4%] vs 149 of 167 [89.2%]; absolute difference, -4.83%; 95% CI, -10.84 to 1.19; eTICI of 2c or greater following the first pass: 76 of 173 [43.7%] vs 74 of 167 [44.3%]; absolute difference, -0.63%; 95% CI, -9.48 to 8.21). Symptomatic intracranial hemorrhage occurred in 0 patients in the pRESET group and 2 (1.2%) in the Solitaire group. Mortality occurred in 25 (14.5%) in the pRESET group and in 24 (14.4%) in the Solitaire group at 90 days. Findings of the per-protocol and as-treated analyses were in concordance with findings of the intention-to-treat analysis.

In this study, among patients with Large Vessel Occlusion (LVO) stroke, thrombectomy with the pRESET stent retriever was noninferior to thrombectomy with the Solitaire stent retriever. Findings suggest that pRESET offers a safe and effective option for flow restoration and disability reduction in patients with LVO stroke 2).

1)

Habibi MA, Ahmadvand MH, Delbari P, Sabet S, Zare AH, Mirjani MS, Boskabadi AR, Kolur ZA, Bozorgi M. The safety and efficacy of pRESET stent retriever for treatment of thrombo-embolic stroke; a systematic review and meta-analysis. Neuroradiol J. 2024 Nov 27:19714009241303083. doi: 10.1177/19714009241303083. Epub ahead of print. PMID: 39604086.
2)

Nogueira RG, Lobsien D, Klisch J, Pielenz D, Lobsien E, Sauvageau E, Aghaebrahim N, Möhlenbruch M, Vollherbst D, Ulfert C, Bozorgchami H, Clark W, Priest R, Samaniego EA, Ortega-Gutierrez S, Ghannam M, Lopes D, Billingsley J, Keigher K, Haussen DC, Al-Bayati AR, Siddiqui A, Levy E, Chen M, Munich S, Schramm P, Boppel T, Narayanan S, Gross BA, Roth C, Boeckh-Behrens T, Hassan A, Fifi J, Budzik RF, Tarpley J, Starke RM, Raz E, Brogan G, Liebeskind DS, Hanel RA. Thrombectomy With the pRESET vs Solitaire Stent Retrievers as First-Line Large Vessel Occlusion Stroke Treatment: A Randomized Clinical Trial. JAMA Neurol. 2024 Jan 2. doi: 10.1001/jamaneurol.2023.5010. Epub ahead of print. PMID: 38165690.

Proton magnetic resonance spectroscopic imaging in glioblastoma recurrence diagnosis

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Proton magnetic resonance spectroscopic imaging in glioblastoma recurrence diagnosis

Proton magnetic resonance spectroscopic imaging (MRSI) is a non-invasive imaging technique that assesses the metabolic profile of brain tissues, offering valuable insights into the diagnosis and monitoring of glioblastoma recurrence. By measuring concentrations of metabolites such as choline (Cho), N-acetylaspartate (NAA), and creatine (Cr), MRSI aids in distinguishing between tumor recurrence and treatment-induced changes like radiation necrosis.

Key Metabolites in MRSI

– Choline (Cho): Elevated levels indicate increased cellular membrane turnover, commonly associated with tumor proliferation.

– N-acetylaspartate (NAA): Reduced levels suggest neuronal loss or dysfunction, often observed in tumor regions.

– Creatine (Cr): Serves as a reference metabolite for energy metabolism, typically stable across different tissues.

Chemical Shift Imaging: Provides information about the metabolic composition of tissues. Elevated levels of choline and decreased N-acetylaspartate (NAA) may indicate recurrent tumors.

Choline to N-Acetylaspartate Ratio in Glioblastoma Recurrence Diagnosis

Choline to N-Acetylaspartate Ratio in Glioblastoma Recurrence Diagnosis

Clinical Applications

1. Differentiating Tumor Recurrence from Radiation Injury: MRSI can help distinguish recurrent GBM from radiation-induced changes. Recurrent tumors often exhibit increased Cho/Cr and Cho/NAA ratios, whereas radiation injuries may show different metabolic patterns.

2. Guiding Radiotherapy Planning: Incorporating MRSI into radiotherapy planning allows for targeted dose escalation to metabolically active tumor regions, potentially improving local control and patient outcomes.

3. Monitoring Treatment Response: MRSI enables the assessment of metabolic changes over time, providing insights into treatment efficacy and early detection of recurrence.

Advantages of MRSI

– Non-Invasive: Offers a non-invasive method to assess tumor metabolism without the need for biopsy.

– Metabolic Insights: Provides detailed information on tumor biochemistry, complementing anatomical imaging.

– Early Detection: Facilitates the early identification of tumor recurrence before structural changes become apparent.

Limitations

– Technical Complexity: Requires specialized equipment and expertise for acquisition and interpretation.

– Spatial Resolution: May have lower spatial resolution compared to conventional MRI, potentially limiting the detection of small lesions.

In summary, proton MRSI is a valuable tool in the management of glioblastoma, enhancing the ability to differentiate between tumor recurrence and treatment effects, guiding therapy, and monitoring disease progression.

Systematic Reviews

Of 7350 records for MR spectroscopy, GBM, glioma, recurrence, diffusion, perfusion, pseudoprogression, radiomics, and advanced imaging, they screened 574 papers. A total of 228 were eligible, and analyzed 72 of them, in order to establish the role of each imaging modality and the usefulness and limitations of radiomics analysis 1).

Prospective diagnostic accuracy studies

A prospective single-institutional study aims to determine and validate thresholds for the main metabolite concentrations obtained by MR spectroscopy (MRS) and the values of the apparent diffusion coefficient (ADC) to enable distinguishing tumor recurrence from pseudoprogression. Thirty-nine patients after the standard treatment of a glioblastoma underwent advanced imaging by MRS and ADC at the time of suspected recurrence – the median time to progression was 6.7 months. The highest significant sensitivity and specificity to call the glioblastoma recurrence was observed for the total choline (tCho) to total N-acetyl aspartate (tNAA) concentration ratio with the threshold ≥ 1.3 (sensitivity 100.0% and specificity 94.7%). The ADC mean value higher than 1313 × 10(- 6) mm(2)/s was associated with pseudoprogression (sensitivity 98.3%, specificity 100.0%). The combination of MRS focused on the tCho/tNAA concentration ratio and the ADCmean value represents imaging methods applicable to early non-invasive differentiation between a glioblastoma recurrence and a pseudoprogression. However, the institutional definition and validation of thresholds for differential diagnostics are needed for the elimination of setup errors before the implementation of these multimodal imaging techniques into clinical practice, as well as into clinical trials 2).

Retrospective cohort studies

A study of Lu et al. aimed to evaluate the predictive value of metabolic parameters in preoperative non-enhancing peritumoral regions (NEPTRs) for glioblastoma recurrence, using multivoxel hydrogen proton magnetic resonance spectroscopy (1H-MRS). Clinical and imaging data from patients with recurrent glioblastoma were analyzed. Through co-registration of preoperative and post-recurrence MRI, they identified future tumor recurrence regions (FTRRs) and future non-tumor recurrence regions (FNTRRs) within the NEPTRs. Metabolic parameters were recorded separately for each region. Cox regression analysis was applied to assess the association between metabolic parameters and glioblastoma recurrence. Compared to FNTRRs, FTRRs exhibited a higher Cho/Cr ratio, higher Cho/NAA ratio, and lower NAA/Cr ratio. Both Cho/NAA and Cho/Cr ratios were recognized as risk factors in univariate and multivariate analyses (P < 0.05). The Cox regression model indicated that Cho/NAA > 1.99 and Cho/Cr > 1.73 are independent risk factors for early glioblastoma recurrence. Based on these cut-off values, patients were stratified into low-risk and high-risk groups, with a statistically significant difference in recurrence rates between the two groups (P < 0.01). The Cho/NAA and Cho/Cr ratios in NEPTRs are independent predictors of future glioblastoma recurrence. Specifically, Cho/NAA > 1.99 and/or Cho/Cr > 1.73 in NEPTRs may indicate a higher risk of early postoperative recurrence at these regions 3).

This study demonstrates that metabolic ratios (Cho/NAA and Cho/Cr) in NEPTRs are independent predictors of glioblastoma recurrence and proposes clinically relevant cut-off values for risk stratification. While the findings are promising, limitations such as small sample size, lack of external validation, and potential confounding factors highlight the need for further research. The integration of metabolic and molecular data, along with validation in larger cohorts, could significantly enhance the clinical utility of these predictors.

1)

Sidibe I, Tensaouti F, Roques M, Cohen-Jonathan-Moyal E, Laprie A. Pseudoprogression in Glioblastoma: Role of Metabolic and Functional MRI-Systematic Review. Biomedicines. 2022 Jan 26;10(2):285. doi: 10.3390/biomedicines10020285. PMID: 35203493; PMCID: PMC8869397.
2)

Kazda T, Bulik M, Pospisil P, Lakomy R, Smrcka M, Slampa P, Jancalek R. Advanced MRI increases the diagnostic accuracy of recurrent glioblastoma: Single institution thresholds and validation of MR spectroscopy and diffusion weighted MR imaging. Neuroimage Clin. 2016 Feb 26;11:316-321. doi: 10.1016/j.nicl.2016.02.016. PMID: 27298760; PMCID: PMC4893011.
3)

Lu W, Feng J, Zou Y, Liu Y, Gao P, Zhao Y, Wu X, Ma H. 1H-MRS parameters in non-enhancing peritumoral regions can predict the recurrence of glioblastoma. Sci Rep. 2024 Nov 26;14(1):29258. doi: 10.1038/s41598-024-80610-z. PMID: 39587278.

Bilingualism

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Bilingualism

Bilingualism refers to the ability to use two languages proficiently. A bilingual person can speak, understand, read, and write in two languages with varying degrees of fluency. Bilingualism is not a uniform concept; it can manifest in different ways depending on factors such as language proficiency, context, and the timing of learning.

Here are key points about bilingualism:

### Types of Bilingualism: 1. Simultaneous Bilingualism: This occurs when a person learns two languages from birth or early childhood, typically in a bilingual environment. This is common in families where parents speak different languages.

2. Sequential (or Successive) Bilingualism: This happens when a person learns a second language after already being proficient in a first language, often in childhood or adulthood. For example, a child might learn their native language at home and then acquire a second language at school.

3. Balanced Bilingualism: This refers to a situation where a person has nearly equal proficiency in both languages. While rare, this is the ideal for some bilinguals.

4. Dominant Bilingualism: In this case, one language is stronger or more frequently used than the other. For instance, someone who speaks both Spanish and English but uses English more often may be considered dominant in English.

5. Passive Bilingualism: A person understands a second language but is not able to speak or use it actively.

### Cognitive and Neurological Aspects: – Cognitive Benefits: Bilingualism has been linked to cognitive advantages, such as better executive function (e.g., problem-solving, multitasking, and memory) and delayed onset of age-related cognitive decline, including Alzheimer’s disease.

– Language Switching: Bilinguals can switch between languages depending on the context, a process known as code-switching. This flexibility relies on the brain’s ability to manage and control both languages.

– Brain Activation: Studies have shown that bilinguals often have denser gray matter in areas of the brain related to language processing. The brain of a bilingual person is particularly adept at managing the interference from competing languages, which enhances cognitive flexibility.

### Social and Cultural Aspects: – Cultural Identity: Bilingualism can be tied to cultural identity. For many bilinguals, each language may represent a different cultural aspect of their life, and they may switch languages depending on the social or cultural context.

– Communication: Bilinguals have the advantage of communicating with a wider range of people across different linguistic communities, which can be particularly useful in multilingual regions or professional settings.

### Challenges of Bilingualism: – Language Interference: Sometimes, one language can interfere with the other, causing errors such as mixing vocabulary, grammar, or pronunciation (e.g., “Spanglish” or “Franglais”). This is especially common in simultaneous bilinguals.

– Language Maintenance: Bilinguals may struggle to maintain proficiency in both languages, especially if one language is used more frequently than the other. This can lead to language attrition, where one language becomes weaker over time.

– Social Perceptions: In some regions, bilingual individuals may face social stigma or discrimination, especially if one of their languages is viewed as less prestigious or less widely spoken.

### Conclusion: Bilingualism is a dynamic and complex phenomenon that involves not just language proficiency but also cognitive, social, and cultural factors. It provides numerous benefits, both personally and professionally, but can also come with challenges, particularly in balancing both languages and navigating social perceptions.

The utility of intraoperative mapping in multilingual patients with brain tumors in speech-eloquent locations is evidenced by reports of heterogeneity of the location and number of language areas. Furthermore, preserving the ability to switch between languages is crucial for multilingual patients’ communication and quality of life. Barua et al. report the first case of intraoperative bilingual and language-switching testing in a child undergoing awake craniotomy for a tumor within the left superior temporal gyrus using a novel test paradigm. Stimulation of the posterior superior temporal gyrus resulted in anomia when switching from Polish to English, in the absence of any stimulation effect on switching from English to Polish or object naming in each language 1)

The article *“Bilingual awake craniotomy with English and Polish language mapping in a 15-year-old patient provides evidence for the role of the left superior temporal gyrus in language switching”* (Acta Neurochir, 2024 Nov 13;166(1):452) presents an intriguing study on the role of the left superior temporal gyrus (STG) in bilingual language switching. The authors—Neil U Barua, Hajira Mumtaz, Sonia Mariotti, Molly Cree, Agdaliya Mikhalkova, Greg A Fellows, and Anna E Piasecki—explore a novel approach to intraoperative language mapping in a young multilingual patient undergoing awake craniotomy for a tumor in the left superior temporal gyrus. This report highlights the utility of mapping bilingual language areas and provides significant insights into the complex brain regions involved in switching between languages.

### Strengths:

1. Novel Methodology: The use of a bilingual awake craniotomy in a 15-year-old patient is groundbreaking, as it is the first report of such an approach for mapping language switching between English and Polish. This methodology can offer a deeper understanding of the neural mechanisms underlying multilingual language processing, especially in children, who may exhibit unique brain adaptations.

2. Clinical Relevance: The study is highly relevant for clinical neuropsychology, particularly for multilingual patients with brain tumors in speech-eloquent regions. By demonstrating the distinct brain activity involved in language switching, the findings may guide surgeons in preserving both language abilities during resection of tumors in these areas, ultimately improving postoperative quality of life for patients.

3. Specific Findings: The case highlights the critical role of the posterior superior temporal gyrus (STG) in switching between languages. The stimulation-induced anomia specifically when switching from Polish to English—without affecting the ability to name objects in each language individually—emphasizes the specialized role of the STG in language switching rather than simple language production. This nuanced finding adds to the existing body of literature and suggests the need for further studies to map out language-specific regions more thoroughly.

### Weaknesses:

1. Generalizability: As a single case report, the findings should be viewed with caution. It is difficult to generalize the results to other bilingual individuals, particularly in different age groups, with different language pairs, or those with other neurological conditions. The authors themselves acknowledge that further studies with larger sample sizes are needed to confirm the results and expand the findings to a wider population.

2. Language Pair Considerations: The study examines only two languages—English and Polish. While this is an important step, the findings are limited to this particular language pair. Different language pairs may activate different regions of the brain due to variations in phonology, syntax, and other language-specific features. It would be interesting to see if similar results are observed in individuals who speak languages that are typologically distant, such as English and Mandarin, or among individuals with more complex multilingual profiles.

3. Neuroplasticity: The study does not address the potential influence of neuroplasticity on language functions in multilingual individuals. Children, in particular, may demonstrate different neural organization compared to adults, and the influence of age, experience, and neural reorganization in response to the tumor could affect the outcome. This aspect would benefit from further exploration.

### Suggestions for Future Research:

– Larger Cohort Studies: It would be valuable to conduct similar research on a larger cohort of multilingual patients to identify whether the observed effects are consistent across different language pairs and in different populations (e.g., adults vs. children).

– Long-Term Follow-Up: A longitudinal follow-up of postoperative language outcomes would offer insight into the long-term impact of preserving specific areas of the STG and other brain regions involved in language switching.

– Comparative Language Pairs: Future studies could explore different language pairs or more complex multilingual cases, which might reveal additional findings or patterns in language representation and switching.

### Conclusion:

This report provides compelling evidence for the involvement of the left superior temporal gyrus in language switching, contributing valuable knowledge to the field of multilingual neuropsychology. Although the findings are based on a single case, the study demonstrates the importance of intraoperative language mapping in bilingual patients undergoing neurosurgery. The findings hold promise for improving surgical outcomes for multilingual individuals, offering a more nuanced understanding of how the brain manages multiple languages. Nonetheless, further research is needed to validate these results and extend the implications to broader clinical practice.

Neural basis of language switching and the cognitive models of bilingualism remain controversial.

Sierpowska et al. explored the functional neuroanatomy of language switching implementing a new multimodal protocol assessing neuropsychological, functional magnetic resonance, and intraoperative Electrostimulation mapping results. A prospective series of 9 Spanish-Catalan bilingual candidates for awake brain surgery underwent a specific language-switching paradigm implemented both before and after surgery, throughout the Electrostimulation procedure, and during functional magnetic resonance both pre-and postoperatively. All patients were harboring left-hemispheric intrinsic brain lesions and were presenting functional language-related activations within the affected hemisphere. Language functional maps were reconstructed based on the intraoperative Electrostimulation results and compared to the functional magnetic resonance findings. Single language-naming sites (Spanish and Catalan), as well as language-switching naming sites were detected by Electrostimulation mapping in 8 patients (in one patient only Spanish-related sites were detected). Single naming points outnumbered the switching points and did not overlap with each other. Within the frontal lobe, the single language naming sites were found significantly more frequently within the inferior frontal gyrus as compared to the middle frontal gyrus [X2 (1) = 20.3, p < .001]. Contrarily, switching naming sites were distributed across the middle frontal gyrus significantly more often than within the inferior frontal gyrus [X2 (1) = 4.1, p = .043]. Notably, there was not always an overlap between functional magnetic resonance and Electrostimulation mapping findings. After surgery, patients did not report involuntary language switching and their neuropsychological scores did not differ significantly from the pre-surgical examinations. Our results suggest a functional division of the frontal cortex between naming and language switching functions, supporting that non-language specific cognitive control prefrontal regions (middle frontal gyrus) are essential to maintain effective communication together with the classical language-related sites (inferior frontal gyrus) 2).

1)

Barua NU, Mumtaz H, Mariotti S, Cree M, Mikhalkova A, Fellows GA, Piasecki AE. Bilingual awake craniotomy with English and Polish language mapping in a 15-year-old patient provides evidence for the role of the left superior temporal gyrus in language switching. Acta Neurochir (Wien). 2024 Nov 13;166(1):452. doi: 10.1007/s00701-024-06358-7. PMID: 39535621.
2)

Sierpowska J, Fernandez-Coello A, Gomez-Andres A, Camins À, Castañer S, Juncadella M, Gabarrós A, Rodríguez-Fornells A. Involvement of the middle frontal gyrus in language switching as revealed by Electrostimulation mapping and functional magnetic resonance imaging in bilingual brain tumor patients. Cortex. 2017 Nov 14;99:78-92. doi: 10.1016/j.cortex.2017.10.017. [Epub ahead of print] PubMed PMID: 29197227.

Ultrasonography-guided nerve block

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Ultrasonography-guided nerve block

Ultrasound-guided nerve blocks were first described in anesthesiology literature in 1978 when La Grange et al. utilized a Doppler device while performing supraclavicular brachial plexus blocks 1)

An Ultrasonography-guided nerve block is a procedure used for pain management by delivering anesthetic directly to nerves under ultrasound guidance. UGNBs are commonly used in emergency departments, operating rooms, and pain management settings as part of a multimodal approach to analgesia.

Procedure Overview

1. Ultrasound Guidance: UGNBs are performed using an ultrasound device, which helps visualize the targeted nerve and surrounding anatomy. This visualization enables precise placement of the anesthetic, reducing the risk of complications.

2. Anesthetic Injection: Once the nerve is located, a needle is inserted near the nerve, and the anesthetic is injected. The ultrasound ensures that the needle is in the correct position, minimizing the chances of injecting into blood vessels or other structures.

3. Types of Nerve Blocks: Common UGNB types include:

  1. Fascia Iliaca Block: Often used for hip fractures or femoral nerve pain.
  1. Interscalene Block: Commonly for shoulder surgeries.
  1. Axillary Block: For hand or forearm procedures.
  1. Popliteal Sciatic Block: For foot and ankle surgeries.

Clinical Applications

1. Pain Management in Acute Settings: UGNBs are widely used for immediate pain relief in trauma cases, orthopedic injuries, and post-surgical pain. In emergency departments, they provide rapid pain control, often avoiding or reducing the need for opioid medications.

2. Opioid-Sparing Effects: As UGNBs target specific nerves, they can achieve high levels of pain relief without the systemic side effects of opioids, reducing risks associated with opioid use, such as dependence and respiratory depression.

3. Improved Patient Comfort and Outcomes: By offering more effective pain control with fewer systemic side effects, UGNBs improve overall patient satisfaction and can facilitate earlier patient discharge and recovery.

Safety and Efficacy

1. Low Complication Rates: UGNBs, particularly with ultrasound guidance, have shown low rates of complications. Ultrasound visualization reduces the risk of nerve damage, vessel puncture, and incorrect injection sites, which are higher risks in blind (non-ultrasound-guided) blocks.

2. Training and Skill Requirements: The success and safety of UGNBs largely depend on the operator’s skill. Training in ultrasound use and nerve identification is essential, and studies suggest that, with adequate training, even less experienced clinicians can perform UGNBs effectively and safely.

3. Adverse Events: Although rare, complications like local anesthetic systemic toxicity (LAST), nerve injury, or infection can occur. Proper technique and knowledge of ultrasound-guided procedures significantly mitigate these risks.

Research and Evidence

Studies on UGNBs in emergency and acute care settings support their effectiveness and safety. They show that UGNBs can achieve significant pain relief, with many patients reporting reductions in pain scores by 50% or more. Moreover, complication rates remain low, with UGNBs increasingly recommended as part of multimodal pain management, especially for patients who may benefit from opioid-sparing strategies.

Conclusion

Ultrasonography-guided nerve blocks are a valuable tool in modern pain management. By allowing precise nerve targeting, UGNBs offer significant pain relief with minimal systemic effects, positioning them as a safe, effective alternative or supplement to opioid medications in various medical settings. As UGNBs gain wider adoption, consistent training, and quality control will be essential to maximize their benefits and ensure patient safety.

Retrospective multicenter observational cohort studies

Design, setting, and participants: This cohort study included data from the National Ultrasound-Guided Nerve Block Registry, a retrospective multicenter observational registry encompassing procedures performed in 11 EDs in the US from January 1, 2022, to December 31, 2023, of adult patients who underwent a UGNB.

Exposure: UGNB encounters.

Main outcomes and measures: The primary outcome of this study was complication rates associated with ED-performed UGNBs recorded in the National Ultrasound-Guided Nerve Block Registry from January 1, 2022, to December 31, 2023. The secondary outcome was patient pain scores of ED-based UGNBs. Data for all adult patients who underwent an ED-based UGNB at each site were recorded, as were the volume of UGNB at each site and procedural outcomes (including complications). Data were analyzed using descriptive statistics of all variables.

Results: In total, 2735 UGNB encounters among adult patients (median age, 62 years [IQR, 41-77 years]; 51.6% male) across 11 EDs nationwide were analyzed. Fascia iliaca blocks were the most commonly performed UGNBs (975 of 2742 blocks [35.6%]). Complications occurred at a rate of 0.4% (10 of 2735 blocks). One episode of local anesthetic systemic toxicity requiring an intralipid was reported. Overall, 1320 of 1864 patients (70.8%) experienced 51% to 100% pain relief following UGNBs. Operator training levels varied, although resident physicians performed in 1953 of 2733 procedures (71.5%).

Conclusions and Relevance: The findings of this cohort study of 2735 UGNB encounters support the safety of UGNBs in ED settings and suggest an association with improvement in patient pain scores. Broader implementation of UGNBs in ED settings may have important implications as key elements of multimodal analgesia strategies to reduce opioid use and improve patient care 2)

This study, published in *JAMA Network Open*, investigates the complication rates and effectiveness of ultrasonography-guided nerve blocks (UGNBs) as a modality for acute pain management in emergency department (ED) settings. Based on 2735 UGNB procedures from 11 EDs in the U.S., the study found a complication rate of 0.4%, with significant pain relief observed in 70.8% of patients. This evidence underscores UGNBs’ safety and efficacy, making a strong case for their broader adoption in EDs.

Strengths of the Study:

1. Large Sample Size: With 2735 UGNB procedures, this study offers substantial statistical power, lending robustness to its findings regarding complication rates and pain management effectiveness.

2. Multicenter Data Collection: Data gathered from 11 different EDs across the U.S. adds diversity to the sample, increasing the generalizability and relevance of the findings for other ED settings.

3. Low Complication Rate: The reported complication rate of 0.4% supports the safety profile of UGNBs, a key concern in emergency settings. The low incidence of adverse events, despite varied operator training levels, supports the feasibility of UGNB implementation.

4. Quantifiable Pain Relief: With 70.8% of patients experiencing substantial pain relief, the study successfully demonstrates the efficacy of UGNBs as an alternative to opioid-based pain management, highlighting its potential for reducing opioid use in acute pain settings.

Limitations and Areas for Improvement:

1. Lack of Control Group: The absence of a control group (e.g., patients receiving standard pain management without UGNBs) makes it difficult to attribute observed pain relief outcomes solely to UGNBs without considering other factors that might have contributed.

2. Variability in Operator Training: Although the study notes that most procedures were performed by resident physicians, it does not provide a detailed analysis of how operator experience levels may have impacted complication rates or pain outcomes. Further stratifying data based on operator training could yield insights into the learning curve associated with UGNBs.

3. Limited Analysis of Complications: The study briefly mentions a single case of local anesthetic systemic toxicity but lacks in-depth discussion on the nature of the complications or potential preventive measures. This aspect could be better explored to enhance understanding of specific risks associated with UGNBs.

4. Single-Country Focus: Since all data are from U.S. EDs, the study’s findings may not be as generalizable to EDs in other healthcare systems, where different training standards or equipment availability may influence UGNB safety and efficacy.

Implications for Practice:

The study’s conclusions are promising for EDs seeking multimodal analgesia solutions. Implementing UGNBs more broadly in ED settings could mitigate opioid dependency risks and enhance patient outcomes in acute pain management. However, integrating UGNBs would necessitate comprehensive training programs to ensure operator competency, especially among resident physicians, who conducted the majority of the blocks in this study.

Conclusion:

This study provides valuable insights into the role of UGNBs in ED pain management, underscoring their safety and effectiveness. While UGNBs show potential for wider application in ED settings, further research with controlled methodologies and a focus on operator training levels would help solidify the findings. In summary, the study presents a compelling case for UGNBs as part of multimodal analgesia in emergency care but underscores the need for continued evaluation of best practices for their safe and effective implementation.

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la Grange P, Foster PA, Pretorius LK. Application of the Doppler ultrasound bloodflow detector in supraclavicular brachial plexus block. Br J Anaesth. 1978 Sep;50(9):965-7. doi: 10.1093/bja/50.9.965. PMID: 708565.
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Goldsmith A, Driver L, Duggan NM, Riscinti M, Martin D, Heffler M, Shokoohi H, Dreyfuss A, Sell J, Brown C, Fung C, Perice L, Bennett D, Truong N, Jafry SZ, Macias M, Brown J, Nagdev A. Complication Rates After Ultrasonography-Guided Nerve Blocks Performed in the Emergency Department. JAMA Netw Open. 2024 Nov 4;7(11):e2444742. doi: 10.1001/jamanetworkopen.2024.44742. PMID: 39535792.

Associations of Microvascular Risk Factors with Sporadic Vestibular Schwannoma Outcomes Following Stereotactic Radiosurgery

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The article in *Otolaryngology–Head and Neck Surgery* provides a valuable investigation into how microvascular risk factors might influence outcomes following vestibular schwannoma radiosurgery. By assessing a large cohort of 749 patients treated between 2000 and 2022, the study explores the connections between microvascular risk factors—like hypertension, smoking, obesity, and coronary bypass history—and the efficacy and side effects of SRS 1)

Strengths

1. Large Sample Size and Cohort Design: The authors reviewed a substantial cohort of 749 patients across two decades. This sample size enhances the reliability and generalizability of findings, especially when considering the rare nature of VS.

2. Specific Risk Factors Analysis: The study dives into specific microvascular risk factors, evaluating how each may impact tumor control and adverse outcomes such as facial nerve paresis and hearing loss. This approach allows for a nuanced understanding of the multifactorial risks associated with SRS in VS treatment.

3. Clinical Relevance for Patient Counseling: The findings offer practical implications for clinical counseling. For example, identifying smoking as a risk factor for accelerated hearing loss and hypertension as a predictor for facial nerve weakness can help clinicians guide patients more effectively regarding the potential risks of SRS based on individual health backgrounds.

4. Statistical Approach: The use of Cox proportional hazards regression to assess associations and the adjustment for variables like age and ipsilateral hearing status in hearing loss analysis provide a robust statistical foundation, increasing the validity of the results.

Limitations

1. Lack of Mechanistic Insight: While the study identifies correlations between microvascular risk factors and SRS outcomes, it does not provide insights into the biological mechanisms. The authors hypothesize that microvascular hyalinization and ischemia could play a role in VS tumor control, yet no direct evidence is presented.

2. Limited Data on Tumor Control: Despite a detailed investigation of complications, the study lacks significant findings regarding tumor control in relation to microvascular risk factors. This could be due to limited follow-up on tumor growth or insufficient sensitivity of the study to detect such associations, limiting the applicability of the findings to tumor management.

3. Potential Confounding Factors: Although the study adjusts for age and ipsilateral hearing status, other potential confounding factors such as overall health status, treatment modalities prior to SRS, and specific lifestyle factors were not discussed in detail, which might influence outcomes like hearing loss or facial nerve complications.

4. Limited Generalizability Beyond the Study Setting: Conducted within a single tertiary academic center, results might not fully represent diverse patient populations, especially those managed in non-academic or smaller medical centers where treatment protocols may differ.

Conclusion

This study makes a notable contribution to understanding how microvascular risk factors may affect specific outcomes following SRS for sporadic VS. The association of hypertension and coronary artery bypass surgery history with facial nerve paresis, as well as smoking history with accelerated hearing loss, provides valuable insights for clinical decision-making and patient counseling. However, limitations in mechanistic insight and generalizability, as well as the lack of significant findings on tumor control, suggest the need for further research. Future studies could benefit from exploring the biological mechanisms at play and expanding data collection across multiple centers for broader applicability.

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Dornhoffer JR, Babajanian EE, Khandalavala KR, Marinelli JP, Daher GS, Lohse CM, Link MJ, Carlson ML. Associations of Microvascular Risk Factors with Sporadic Vestibular Schwannoma Outcomes Following Stereotactic Radiosurgery. Otolaryngol Head Neck Surg. 2024 Nov 7. doi: 10.1002/ohn.1038. Epub ahead of print. PMID: 39506614.