Privacy-preserving blockchain-based federated learning for brain tumor segmentation.

Improved data sharing between healthcare providers can lead to a higher probability of accurate diagnosis, more effective treatments, and enhanced capabilities of healthcare organizations. One critical area of focus is brain tumor segmentation, a complex task due to the heterogeneous appearance, irregular shape, and variable location of tumors. Accurate segmentation is essential for proper diagnosis and effective treatment planning, yet current techniques often fall short due to these complexities. However, the sensitive nature of health data often prohibits its sharing. Moreover, the healthcare industry faces significant issues, including preserving the privacy of the model and instilling trust in the model. This paper proposes a framework to address these privacy and trust issues by introducing a mechanism for training the global model using federated learning and sharing the encrypted learned parameters via a permissioned blockchain. The blockchain-federated learning algorithm we designed aggregates gradients in the permissioned blockchain to decentralize the global model, while the introduced masking approach retains the privacy of the model parameters. Unlike traditional raw data sharing, this approach enables hospitals or medical research centers to contribute to a globally learned model, thereby enhancing the performance of the central model for all participating medical entities. As a result, the global model can learn about several specific diseases and benefit each contributor with new disease diagnosis tasks, leading to improved treatment options. The proposed algorithm ensures the quality of model data when aggregating the local model, using an asynchronous federated learning procedure to evaluate the shared model's quality. The experimental results demonstrate the efficacy of the proposed scheme for the critical and challenging task of brain tumor segmentation. Specifically, our method achieved a 1.99% improvement in Dice similarity coefficient for enhancing tumors and a 19.08% reduction in Hausdorff distance for whole tumors compared to the baseline methods, highlighting the significant advancement in segmentation performance and reliability.

Consensus Review on Strategies to Improve Delivery Across the BBB Including Focused Ultrasound.

Drug delivery to the central nervous system (CNS) has been a major challenge for CNS tumors due to the impermeability of the blood brain barrier (BBB). There have been a multitude of techniques aimed at overcoming the BBB obstacle aimed at utilizing natural transport mechanisms or bypassing the BBB which we review here. Another approach that has generated recent interest in the recently published literature is to use new technologies (Laser Interstitial Thermal Therapy, LITT; or Low Intensity Focused Ultrasound, LIFU) to temporarily increase BBB permeability. This review overviews the advantages, disadvantages, and major advances of each method. LIFU has been a major area of research to allow for chemotherapeutics to cross the BBB which has a particular emphasis in this review. While most of the advances remain in animal studies, there are an increasing number of translational clinical trials which will have results in the next few years.

A Nod for Meckel: A Novel Surgical Position Utilizing Meckel's Cave Anatomy for Percutaneous Glycerol Rhizotomy in Trigeminal Neuralgia.

Objective We aim to describe a novel positioning technique using a specific surgical table to achieve the optimal angle during percutaneous glycerol rhizotomy (PGR) for trigeminal neuralgia (TN). Design This is a descriptive and photographic analysis of successful cases for future implementation. Setting This study was conducted at a single-institution, academic center. Participants The participants were adult patients with TN who underwent PGR and provided consent for publication. Main Outcome Measures Primary outcomes of this study were TN symptomatic relief and surgical complications. Results The use of a beach chair sliding headboard surgical table for PGR is plausible and ensures precise and immobile head flexion for 1 hour postglycerol injection. There were no intraoperative or postoperative complications. All patients achieved successful reduction of TN symptoms. Conclusions Utilizing this new method of intraoperative navigation with a unique surgical table in the upright position, surgeons may achieve precise head adjustments post-PGR. Head flexion has been postulated as a means of ensuring glycerol containment in Meckel's cave. This method can help standardize this procedure for future systematic studies on the importance of head positioning post-PGR.

Improvement in Hearing Loss Following Posterior Fossa Arachnoid Cyst Fenestration: A Case Study.

Arachnoid cysts are abnormal intradural collections of cerebrospinal fluid. For posterior fossa arachnoid cysts (PFACs), symptoms vary greatly, often relating to cranial nerve impingement and/or hydrocephalus. Literature on long-term symptomatic and radiographic follow-up of PFACs is lacking. This case study describes a 32-year-old man who presented with headaches and left-sided hearing loss and was found to have a large left-sided cerebellopontine angle arachnoid cyst with syrinx and ventriculomegaly. After PFAC fenestration and excision, his headaches resolved and his hearing markedly improved. At the one-year postoperative evaluation, symptom improvement persisted, and MRI demonstrated a stable decreased cyst and near-complete resolution of his syrinx.

Knowledge Review of Spinal Deformity and the Need for Fusion and Fixation following Treatment for Spinal Tumors among the Pediatric Age Group.

BACKGROUND: Spinal tumors are rare pathology in the pediatric population. The tumors can be classified as extradural, intradural extramedullary, or intramedullary. Any of the spinal tumors can eventually lead to spinal deformity. The progressive spinal deformity can be part of the initial presentation or evolve on long follow-up, even years after the initial intervention and treatment. SUMMARY: Management of spinal deformity associated with spinal tumors in children is not well defined. Patients with progressive symptoms and even neurological deficits need correction for their deformity when diagnosed. Patients that do not have pain or related neurological deficits should be evaluated for the severity of their deformity and followed long-term. Special consideration is needed for young patients who need multilevel surgery or have deformity at presentation. KEY MESSAGES: When considering the need for instrumentation and fusion, the surgeon should consider the age of the patient, expected future growth of the spine, neurologic status, extent of initial deformity, and the number of vertebral levels involved by tumor. Providers should also consider how surgery may fix or prevent deformity, especially when instrumentation can affect imaging at follow-up.

Alkyl-substituted N-methylaryl-N'-aryl-4-aminobenzamides: A new series of small molecule inhibitors for Wip1 phosphatase.

The wild-type p53 induced phosphatase 1 (Wip1), a member of the serine/threonine-specific PP2C family, is overexpressed in numerous human cancers. Wip1 dephosphorylates p53 as well as several kinases (such as p38 MAPK, ATM, Chk1, and Chk2) in the DNA damage response pathway that are responsible for maintaining genomic stability and preventing oncogenic transformation. As a result, Wip1 is an attractive target for synthetic inhibitors that could be further developed into therapeutics to treat some cancers. In this study, we report a series of alkyl-substituted N-methylaryl-N'-aryl-4-aminobenzamides and their inhibitory activity of the Wip1 phosphatase. A straightforward synthetic route was developed to synthesize the target compounds from commercially available starting materials. Three different portions (R1, R2, R3) of the core scaffold were extensively modified to examine structure-activity relationships. This study revealed interesting trends about a new molecular scaffold to inhibit Wip1.

Spontaneous resolution of cerebral arteriovenous malformation after liver transplant: illustrative case.

BACKGROUND: Cerebral arteriovenous malformations (AVMs) have historically been considered congenital lesions with treatment options including surgery, radiation therapy, and observation. Spontaneous resolution of cerebral AVMs remains an exceedingly rare event with poorly understood pathophysiology. MATERIALS AND METHODS: Herein we report a retrospective case review of a 28-year-old man with alcoholic cirrhosis who presented with a seizure 3 weeks after liver transplantation. Neuroimaging confirmed the presence of a Spetzler-Martin grade 2 AVM in the right frontal lobe. Due to the recent liver transplantation, treatment was deferred at the time of initial diagnosis and the patient was observed for a course of 1 year. Follow-up imaging 1 year later showed resolution of the AVM, confirmed by a catheter angiogram. CONCLUSION: Spontaneous resolution of cerebral AVMs is a rare event. Treatment of chronic liver disease resulted in the normalization of angiogenic factors that likely led to AVM resolution. This case provides valuable insight into the vital role of angiogenesis in the natural history of AVMs.

Sacroiliac joint arthropathy in adult spinal deformity patients with long constructs to the pelvis.

OBJECTIVE: Sacroiliac joint (SIJ) arthropathy is an increasingly recognized problem in adult spinal deformity patients undergoing long construct surgery. S2-alar-iliac (S2AI) screw instrumentation is thought to reduce morbidity from pelvic fixation in these patients. The goal of this study is to assess the overall incidence of SIJ arthropathy in patients with long constructs to the pelvis as well as compare SIJ outcomes of partially threaded (PT) versus fully threaded (FT) S2AI screws. METHODS: Data of eligible patients were collected from a prospectively maintained database with retrospective review of electronic records at an academic institution between 2016 and 2019. RESULTS: 65 consecutive patients who underwent S2AI screw instrumentation (40 in PT group, 25 in FT group) were enrolled. The rate of postoperative SIJ pain was higher in the PT (52.5 %) compared to FT (32 %) group. There was a significantly shorter time-to-pain development in the PT compared to FT group (11.8 versus 20.1 months, respectively). Of those who developed SIJ pain in the PT group, the pain worsened in 80.9 % versus only 25 % of those in the FT group despite conservative treatment. Cox regression found the PT group more likely to develop SIJ pain at any point during follow-up compared to the FT group (Hazard Ratio = 7.308). SIJ fusion was not detected on imaging of any patient during follow-up. CONCLUSION: FT S2AI screws are associated with better SIJ outcomes compared to PT screws. However, our data suggest that S2AI screw instrumentation is not sufficient to achieve fusion or prevent development of SIJ pain. Concurrent SIJ fusion may be necessary in patients with long constructs to prevent SIJ arthropathy.

Ultraviolet-B Radiation Stress-Induced Toxicity and Alterations in Proteome of Deinococcus radiodurans.

Deinococcus radiodurans is a polyextremophilic bacterium capable to survive and grow at high doses of ionizing radiation. Besides resistance to ionizing radiation, the bacterium is also resistant to toxic chemicals and desiccation. This study deals with the effects of non-ionizing radiation (ultraviolet-B) on survival, alterations in proteomic profile, and gene expression in D. radiodurans. Exposure of culture to UV-B caused decrease in the percentage survival with increasing duration, complete killing occurred after 16 h. D. radiodurans also showed enhancement in the generation of reactive oxygen species and activities of antioxidative enzymes. Separation of proteins by 2-dimensional gel electrophoresis revealed major changes in number and abundance of different proteins. Twenty-eight differentially abundant protein spots were identified by MALDI-TOF MS/MS analysis and divided into 8 groups including unknown proteins. Gene expression of a few identified proteins was also analyzed employing qRT-PCR, which showed differential expression corresponding to the respective proteins. In silico analysis of certain hypothetical proteins (HPs) suggested that these are novel and as yet not reported from D. radiodurans subjected to UV-B stress. These HPs may prove useful in future studies especially for assessing their significance in the adaptation and management of stress responses against UV-B stress.

Teflon versus Ivalon in Microvascular Decompression for Trigeminal Neuralgia: A 2-Center 10-Year Comparison.

BACKGROUND: Trigeminal neuralgia features jolts of pain along the distribution of the trigeminal nerve. If patients fail conservative management, microvascular decompression (MVD) is typically the next step in treatment. MVD consists of implanting a separating material, often Teflon, between the nerve and compressive lesions. A review found similar success and complication rates between Teflon and Ivalon, another commonly used material. The aim of this study was to analyze outcomes and complications associated with Teflon and Ivalon in MVD. METHODS: We conducted a 2-center retrospective cohort study of trigeminal neuralgia treated with MVD between 2005 and 2019. Patients with no postoperative follow-up were excluded. Postoperative pain was graded using the Barrow Neurological Institute (BNI) pain intensity score. Relapse was defined as a BNI score of 4-5 during follow-up after initial pain improvement or an initial BNI score of 1-3. RESULTS: The study included 221 MVD procedures in 219 patients. Ivalon was implanted in 121 procedures, and Teflon was implanted in 100 procedures. Multivariate analysis found that implant type had no effect on final BNI score (P = 0.305). Relapse rates were similar at 5- and 10-year follow-up (5-year: Ivalon 10.7%, Teflon 18.0%, P = 0.112; 10-year: Ivalon 11.6%, Teflon 19.0%, P = 0.123). There was no difference in postoperative immediate facial numbness (P = 0.125). Postoperative hearing difficulty was higher in the Ivalon cohort (8.4% vs. 1.0%; P = 0.016). CONCLUSIONS: We found no significant difference in final BNI score or risk of relapse between Ivalon and Teflon. Complications were similar, although Ivalon was more associated with temporary postoperative hearing loss.

An Integration of blockchain and AI for secure data sharing and detection of CT images for the hospitals.

Deep learning, for image data processing, has been widely used to solve a variety of problems related to medical practices. However, researchers are constantly struggling to introduce ever efficient classification models. Recent studies show that deep learning can perform better and generalize well when trained using a large amount of data. Organizations such as hospitals, testing labs, research centers, etc. can share their data and collaboratively build a better learning model. Every organization wants to retain the privacy of their data, while on the other hand, these organizations want accurate and efficient learning models for various applications. The concern for privacy in medical data limits the sharing of data among multiple organizations due to some ethical and legal issues. To retain privacy and enable data sharing, we present a unique method that combines locally learned deep learning models over the blockchain to improve the prediction of lung cancer in health-care systems by filling the defined gap. There are several challenges involved in sharing that data while maintaining privacy. In this paper, we identify and address such challenges. The contribution of our work is four-fold: (i) We propose a method to secure medical data by only sharing the weights of the trained deep learning model via smart contract. (ii) To deal with different sized computed tomography (CT) images from various sources, we adopted the Bat algorithm and data augmentation to reduce the noise and overfitting for the global learning model. (iii) We distribute the local deep learning model wights to the blockchain decentralized network to train a global model. iv) We propose a recurrent convolutional neural network (RCNN) to estimate the region of interest (ROI) in theCT images. An extensive empirical study has been conducted to verify the significance of our proposed method for better prediction of cancer in the early stage. Experimental results of the proposed model can show that our proposed technique can detect the lung cancer nodules and also achieve better performance.

Nicotine inhibits MAPK signaling and spheroid invasion in ovarian cancer cells.

Nicotine is the major addictive component of cigarette smoke and although it is not considered carcinogenic, it can enhance or inhibit cancer cell proliferation depending on the type of cancer. Nicotine mediates its effects through nicotinic acetylcholine receptors (nAChRs), which are expressed in many different neuronal and non-neuronal cell types. We observed that the nAChR α4, α5, α7 subunits were expressed in ovarian cancer (OC) cells. Nicotine inhibited the proliferation of SKOV3 and TOV112D OC cells, which have TP53 mutation and wild-type KRAS, but did not inhibit the proliferation of TOV21G or HEY OC cells, which have KRAS mutation and wild-type TP53. Exposure to nicotine for 96 h led to a significant reduction in the amounts of activated extracellular signal-regulated kinase (ERK) and activated p38 mitogen-activated protein kinases (MAPKs) in SKOV3 cells, and in activated ERK in TOV112D cells. In addition, SKOV3 and TOV112D invasion and spheroid formation were substantially inhibited by siRNA knockdown of mixed lineage kinase 3 (MLK3), or MEK inhibition. Nicotine treatment reduced SKOV3 and TOV112D spheroid invasion and compaction but did not significantly affect spheroid formation. Furthermore, SKOV3 spheroid invasion was blocked by p38 inhibition with SB202190, but not by MEK inhibition with U0126; whereas TOV112D spheroid invasion was reduced by MEK inhibition, but not by p38 inhibition. These results indicate that nicotine can suppress spheroid invasion and compaction as well as proliferation in SKOV3 and TOV112D OC cells; and p38 and ERK MAPK signaling pathways are important mediators of these responses.

The Return Back to Typical Practice from the "Battle Plan" of the Coronavirus Disease 2019 (COVID-19) Pandemic: A Comparative Study.

BACKGROUND: Every aspect of the medical field has been heavily affected by the coronavirus disease 2019 (COVID-19) pandemic, and neurosurgical services are no exception. Several departments have reported their experiences and protocols to provide insights for others impacted. The goals of this study are to report the load and variety of neurosurgical cases and clinic visits after discontinuing the COVID-19 Battle Plan at an academic tertiary care referral center to provide insights for other departments going through the same transition. METHODS: The clinical data of all patients who underwent a neurosurgical intervention between May 4, 2020, and June 4, 2020 were obtained from a prospectively maintained database. Data of the control group were retrospectively collected from the medical records to compare the types of surgeries/interventions and clinic visits performed by the same neurosurgical service before the COVID-19 pandemic started. RESULTS: One hundred sixty-one patients underwent neurosurgical interventions, and seven-hundred one patients were seen in clinic appointments, in the 4-week period following easing back from our COVID-19 "Battle Plan." Discontinuing the "Battle Plan" resulted in increases in case load to above-average practice after a week but a continued decrease in clinic appointments throughout the 4 weeks compared with average practice. CONCLUSIONS: As policy-shaping crises like pandemics abate, easing back to "typical" practice can be completed effectively by appropriately allocating resources. This can be accomplished by anticipating increases in neurosurgical volume, specifically in the functional/epilepsy and brain tumor subspecialties, as well as continued decreases in neurosurgical clinic volume, specifically in elective spine.

Teflon™ or Ivalon®: a scoping review of implants used in microvascular decompression for trigeminal neuralgia.

BACKGROUND: Trigeminal neuralgia (TN) is characterized by jolts of pain along the distribution of the trigeminal nerve. If patients fail conservative management, microvascular decompression (MVD) is the next step in treatment. MVD is largely done by placing implant pads between the nerve and compressing vessels. We conducted a literature review to assess effectiveness and safety of Teflon™ and Ivalon® sponges for treatment of TN with MVD. METHODS: In January 2019, PubMed was searched for manuscripts published in English using permutations of "Microvascular decompression", "Teflon", "Ivalon", "Granuloma", "Polytetrafluoroethylene", "Trigeminal Neuralgia", and "Exploration". Success and relapse rates, causes of relapse, and complication rates were analyzed. We analyzed for relationships with ANCOVA at an alpha threshold of .05. RESULTS: Thirty-six studies representing 4273 patients fit inclusion criteria. Twenty-five dealt with initial MVD, 12 with re-do MVD. Initial MVD initial success rates were 85% in patients receiving Teflon™ (57-100%*) and 91% in patients receiving Ivalon® (79-100%*). Recurrence rates were 12% in Teflon™ patients (0*-30%) and 9.1% in Ivalon® patients (0*-19%). In patients with relapses, implants were the cause in 49% of Teflon™ patients (0*-100%*) and 50% of Ivalon® patients (0*-100%*). Complication rates for patients receiving Teflon™ were 12% (0*-34%) and 19% for patients receiving Ivalon® (0*-40%). CONCLUSION: Teflon™ and Ivalon® are two materials used in MVD for TN. It is an effective treatment with long-term symptom relief and recurrence rates of 1-5% each year. Ivalon® has been used less than Teflon™ though is associated with similar success rates and similar complication rates.

Arterial Sling Decompression for Hemifacial Spasm.

Hemifacial spasm is a cranial nerve compression syndrome caused by impingement on the facial nerve most frequently by the anterior inferior cerebellar artery or the posterior inferior cerebellar artery. It can be treated with microvascular decompression (MVD) to separate the nerve from the offending artery. Rarely, a large-caliber vessel such as a dolichoectatic vertebrobasilar system may be implicated, requiring more than an MVD. One technique involves placing a sling around the offending vessel to decompress the facial nerve. We find our "neck-tie" technique to be unique and present it in this detailed video. A 36-year-old-woman presented with a 3-month history of severe left hemifacial spasm refractory to medical management. Imaging demonstrated compression of the left facial nerve and its root entry zone by a dolichoectatic vertebrobasilar complex and anterior inferior cerebellar artery. A left retrosigmoid craniotomy was performed. A Dacron sling was placed around the offending vertebral artery in a "neck-tie" fashion. This sling was used to displace the vertebral artery off of the facial nerve and the sling was then sutured in its final position to the petrous dura. In addition, MVD was performed around the facial nerve's root entry zone. Following sling placement and MVD, neuromonitoring demonstrated absence of abnormal motor responses. Postoperative course was uneventful, she remained neurologically intact, and she remained free of symptoms at 6 months' follow-up. This video highlights the decision making for selecting the appropriate case of hemifacial spasm for sling decompression, the key technical nuances, and complication avoidance in these challenging cases.

Conformational transitions of the sodium-dependent sugar transporter, vSGLT.

Sodium-dependent transporters couple the flow of Na+ ions down their electrochemical potential gradient to the uphill transport of various ligands. Many of these transporters share a common core structure composed of a five-helix inverted repeat and deliver their cargo utilizing an alternating-access mechanism. A detailed characterization of inward-facing conformations of the Na+-dependent sugar transporter from Vibrio parahaemolyticus (vSGLT) has previously been reported, but structural details on additional conformations and on how Na+ and ligand influence the equilibrium between other states remains unknown. Here, double electron-electron resonance spectroscopy, structural modeling, and molecular dynamics are utilized to deduce ligand-dependent equilibria shifts of vSGLT in micelles. In the absence and presence of saturating amounts of Na+, vSGLT favors an inward-facing conformation. Upon binding both Na+ and sugar, the equilibrium shifts toward either an outward-facing or occluded conformation. While Na+ alone does not stabilize the outward-facing state, gating charge calculations together with a kinetic model of transport suggest that the resting negative membrane potential of the cell, absent in detergent-solubilized samples, may stabilize vSGLT in an outward-open conformation where it is poised for binding external sugars. In total, these findings provide insights into ligand-induced conformational selection and delineate the transport cycle of vSGLT.

Phantosmia and Dysgeusia following Endoscopic Transcribriform Approaches to Olfactory Groove Meningiomas.

The endoscopic, endonasal transcribriform approach (EETA) is an important technique used to directly access the anterior skull base and is increasingly being used in the management of olfactory groove meningiomas (OGMs). As this approach requires removal of the cribriform plate and olfactory epithelium en route to the tumor, patients are anosmic postoperatively. Here, we report the development of phantosmia and dysgeusia in two patients who underwent EETAs for OGMs, which has not yet been reported in the literature. We hypothesize that phantosmia and dysgeusia may result from aberrant neuronal signals or misinterpretation centrally from the remaining distal portions of the olfactory and taste pathways. Since EETAs are newer than traditional open craniotomy-based techniques, reporting these outcomes will be important to appropriately counsel patients preoperatively.

Vascularized Fibular Strut Autografts in Spinal Reconstruction after Resection of Vertebral Chordoma or Chondrosarcoma: A Retrospective Series.

BACKGROUND: Margin-free en bloc resection is the best medical practice for primary vertebral chordoma and chondrosarcoma. Spinal reconstruction following total spondylectomy requires reconstructive interbody graft (allograft, devascularized autograft, vascularized autograft, or cage constructs) and instrumentation. An important consideration when choosing grafts and instrumentation is the durability and the long-term success of the fusion without subsidence. OBJECTIVE: To evaluate the potential use of vascularized fibular autograft as a reconstructive strategy after en bloc resection. METHODS: We present a series of 16 patients who underwent spondylectomy for primary vertebral chordoma or chondrosarcoma with reconstruction using a vascularized fibular autograft and anterior/posterior instrumentation between January 2011 and April 2014. We report postoperative neurological outcome, 6-mo rates of fusion and graft subsidence, and other complications. RESULTS: Two patients passed away prior to 6-mo follow-up, and 1 patient was lost to follow-up. The mean follow-up time for the remaining 13 patients was 32 mo. Of these patients, 9 (69%) had evidence of fusion on the 6-mo follow-up computed tomography (CT) scan. Of the 4 patients who did not fuse, 2 had undergone surgery for new tumor diagnoses, 1 for hardware failure, and 1 for graft nonunion. Two patients (15%) had eventual graft subsidence along with hardware failure. CONCLUSIONS: Vascularized fibular strut grafts are a viable method for reconstruction following spondylectomy. We present the largest series of patients to date utilizing this technique. Further comparative studies examining vascularized grafts vs nonvascularized grafts or metallic cage constructs will be important in choosing the best reconstructive strategy.