Neurosurgical Techniques Research Articles

Thermocoagulation as a Surgical Approach for the Treatment of Obsessive-Compulsive Disorder in Refractory Patients: Systematic Review

AbstractObsessive-compulsive disorder (OCD), a disabling chronic neuropsychiatric disease, entails high economic costs to society and has high morbidity and mortality rates. The first-line treatments for OCD are selective serotonin reuptake inhibitors and cognitive-behavioral therapy. However, this disorder has the highest refractory index to noninvasive treatment. Alternatively, ablative thermocoagulation neurosurgical techniques have shown efficacy and few adverse effects. The present systematic review aimed to identify validated protocols to observe the effectiveness of ablative procedures in the treatment of severe and refractory OCD, as well as their possible adverse effects and benefits. This review supports the effectiveness of ablative methods by presenting them as a safe non-experimental therapeutic option for cases of highly-refractory OCD. Additional relevant findings were the improvement in cognitive function, functional capacity, affective orientation, and quality of life, which contribute to the destigmatization of this surgical technique. Further controlled studies may lead to the individualization of recommendations of targets for ablative thermocoagulation.

Encephalitis and Brain Abscess.

This article reviews infections of the brain parenchyma and includes an overview of the epidemiology, pathogenesis, diagnostic approach, and management of infectious encephalitis and brain abscess. The epidemiology of infectious encephalitis and brain abscess has changed in recent years. Vaccination has reduced the incidence of certain viruses associated with encephalitis, while a decrease in fulminant otogenic infections has led to fewer brain abscesses associated with otitis media. However, changes in climate and human population density and distribution have enabled the emergence of newer pathogens and expanded the geographic range of others, and greater adoption of intensive immunosuppressive regimens for autoimmune conditions has increased the risk of opportunistic infections of the brain. The widespread use of early neuroimaging, along with improved diagnostic methodologies for pathogen detection, newer antimicrobial therapies with better brain penetration, and less invasive neurosurgical techniques, has resulted in better outcomes for patients with infectious encephalitis and brain abscess. Novel technologies including metagenomic next-generation sequencing are increasingly being applied to these conditions in an effort to improve diagnosis. Nevertheless, both infectious encephalitis and brain abscess continue to be associated with substantial mortality. Infectious encephalitis and brain abscess can present as neurologic emergencies and require rapid assessment, thorough and appropriate diagnostic testing, and early initiation of empiric therapies directed against infectious agents. Close clinical follow-up, proper interpretation of diagnostic results, and appropriate tailoring of therapeutic agents are essential to optimizing outcomes. Diagnosis and management of parenchymal brain infections are complex and often best achieved with a multidisciplinary care team involving neurologists, neurosurgeons, neuroradiologists, infectious disease physicians, and pathologists.

Chemogenetics: Beyond Lesions and Electrodes.

The field of chemogenetics has rapidly expanded over the last decade, and engineered receptors are currently utilized in the lab to better understand molecular interactions in the nervous system. We propose that chemogenetic receptors can be used for far more than investigational purposes. The potential benefit of adding chemogenetic neuromodulation to the current neurosurgical toolkit is substantial. There are several conditions currently treated surgically, electrically, and pharmacologically in clinic, and this review highlights how chemogenetic neuromodulation could improve patient outcomes over current neurosurgical techniques. We aim to emphasize the need to take these techniques from bench to bedside.

Duplicated Anterior Choroidal Arteries: Literature Review and Clinical Implications.

The anterior choroidal artery supplies important cerebral structures. One important variation of this vessel is duplication. However, little is reported on this anatomical variant and moreover, the prevalence of such a finding varies widely. Therefore, here, we review the literature regarding duplicated anterior choroidal arteries. Clinicians reviewing imaging of the brain, interventionalists, or neurosurgerons should be knowledgeable of variations of the anterior choroidal artery, including its duplication. A better understanding of this anatomy and embryology can improve diagnoses and patient outcomes following interventional or open neurosurgical techniques.

Surgical Evacuation of Intracerebral Hemorrhage: The Potential Importance of Timing.

Surgical Evacuation of Intracerebral Hemorrhage: The Potential Importance of Timing.

Immersive Surgical Anatomy of the Retrosigmoid Approach.

The retrosigmoid approach (RS) approach is the workhorse of the posterolateral neurosurgical techniques to access various posterior fossa structures and even extends into the middle fossa. Many studies have detailed two-dimensional (2D) descriptions of the RS technique from either the lateral or posterior view. This study is the first to provide a comprehensive analysis of the RS technique, soft tissue, extracranial landmarks, and intracranial structures of the posterolateral region using interactive three-dimensional (3D) volumetric models (VMs). The visuospatial understanding of the neuroanatomical structures and landmarks of the RS approach is critical for successful surgeries with minimal complications. This study aims to create a collection of VMs and stereoscopic media for the relevant layer-by-layer soft tissue anatomy and step-by-step surgical technique of the RS approach using cadaveric dissections. Five embalmed heads and one dry skull were used to generate stereoscopic images and VMs using 3D scanning technology (i.e., photogrammetry and structured light scanning) to illustrate and simulate the RS approach. The extracranial structures were divided into myofascial, superficial vascular, superficial nerve, and bony anatomy. The RS approach was divided into seven major steps: patient positioning, incision of the skin, dissection of the scalp flap, dissection of the muscles, craniotomy, dural opening, and closure.Additionally, we described an anatomical classification of surgical corridors based on the cisternal segments of the cranial nerves exposed during the RS approach. We discussed the nuances of the keyhole variations of the RS approach and intradural modifications of the RS approach using 3D VMs to illustrate the surgical corridors and the intradural structures accessed. These interactive VMs allow for clear visualization and dynamically immersive experience for neuroanatomical studies of the RS approach in 360-degrees and virtual reality (VR). Computer graphics can be implemented in neurosurgery to facilitate our topographic knowledge, which is crucial for anatomical education, surgical planning, intraoperative decision making, and postoperative care.

Current Development of Glioblastoma Therapeutic Agents.

Glioblastoma multiforme (GBM) is the most common and aggressive malignant primary brain tumor in humans. Over the past several decades, despite improvements in neurosurgical techniques, development of powerful chemotherapeutic agents, advances in radiotherapy, and comprehensive genomic profiling and molecular characterization, treatment of GBM has achieved very limited success in increasing overall survival. Thus, identifying and understanding the key molecules and barriers responsible for the malignant phenotypes and treatment resistance of GBM will yield new potential therapeutic targets. We review the most recent development of receptor tyrosine kinase targeted therapy for GBM and discuss the current status of several novel strategies with the emphasis on blood-brain barrier penetration as a major obstacle for small-molecule drugs to achieve their therapeutic goals. Likewise, a major opportunity for the treatment of GBM lies in the use of biomarkers for the discovery and development of new receptor tyrosine kinase targeted therapy.

A customized 3D implant to target laser interstitial thermal therapy ablation of a posterior fossa mass

Laser interstitial thermal therapy (LITT) is a minimally invasive neurosurgical technique that has been demonstrated to successfully ablate intracranial tumors. While LITT for supratentorial lesions can often be straightforward, ablation of infratentorial lesions can be difficult with current targeting technologies and instrumentation. The anatomical difficulty of targeting posterior fossa masses can be further complicated in patients who have had a prior craniectomy or other procedure that removed the bone that is required to set the surgical trajectory. This article describes use of a three-dimensional (3D)–printed customized surgical implant to improve and enable targeting of posterior fossa lesions using LITT, particularly in the setting of prior craniectomy. A 3D-printed implant was customized for a patient with a history of metastatic lung cancer and prior posterior fossa craniectomy who presented for treatment of a progressively enlarging contrast-enhancing lesion in the right cerebellar hemisphere. The device included a built-in bolt trajectory for LITT ablation. The temporary implant was successfully fabricated for use with laser ablation of a right cerebellar mass. Three potential trajectories for the LITT bolt were incorporated into the temporary implant, but only the primary trajectory was utilized. Laser ablation was performed with the implant and a SideFire laser probe. Customized 3D-printed implants can enable the use of LITT for patients who would not otherwise be candidates.

From textbook to patient: a practical guide to train the end-to-side microvascular anastomosis

Microvascular anastomosis is one of the most challenging neurosurgical techniques. Mastering this technique allows to perform intracranial bypass with arteries of small caliber usually placed in deep narrow surgical fields. The aim of this paper is to describe step by step end-to-side microanastomosis training method by using polyvinyl alcohol (PVA) hydrogel tubing as it is easily reproducible. The tubing comes in sizes from 0.3 mm to 5 mm and has a texture and consistency similar to real vessels. This is based on the Teishinkai Hospital anastomosis technique. Continuous practice in microvascular anastomosis is of great importance in training vascular neurosurgeon. The PVA hydrogel tubing described in this article are useful and cost-effective material in the training of microvascular anastomosis. This practical guide model is easy to set up for repeated practice, and will contribute to facilitate ‘off-the-job’ training by young neurosurgeons and the development and maintenance of microsurgical skills in both resident neurosurgeons and experts who wish to master the various levels of anastomosis technique. There is no shortcut to master this technique, only hard work and perseverance.

EVALUATION OF RADIOLOGICAL FEATURES AND TUMOUR CHARACTERISTICS AND THEIR SIGNIFICANCE IN OUTOME OF INTRACRANIAL MENINGIOMAS

Meningioma is one of the most common intracranial tumours. Several advancements have been made for establishing the etiopathogenesis of meningiomas, including gene mutation and DNA methylation. Many factors have been found to be associated with tumour grade, time to recurrence, overall survival and prognosis. Today, with the availability of detailed radiological assessment and better micro neurosurgical techniques, the outcome has improved signicantly. This study is aimed at evaluating detailed radiological features of meningiomas along with its characteristics like vascularity, adhesiveness and edema and to determine their signicance in outcome. SUMMARY: Meningioma is amongst the most common brain tumours. Several factors have been found to be associated with its origin, growth, grade, time to recurrence, outcome and overall prognosis. This prospective evaluation of 68 consecutive patients of intracranial meningioma was aimed at evaluating their detailed radiological features along with tumour characteristics like vascularity, adhesiveness and edema and to determine their signicance in outcome. Our study showed MRI was most useful tool for preoperative evaluation of tumour characteristics like edema, vascularity and adhesiveness which guide surgical outcome. Less vascular and adhesive tumours had good outcome as compared to highly vascular and strongly adhesive tumours. Size of tumour too was associated with outcome. In our study, all patients (100%) of grade 0 tumour removal had good outcome which was statistically highly signicant (p<0.01). Most common histological variant was transitional type. We advocate aggressive surgical therapy as the primary and main mode of treatment in relation to the preoperative characteristics and features from imaging studies.

Targeting RTK-PI3K-mTOR Axis in Gliomas: An Update.

Gliomas are the most common and challenging malignancies of the central nervous system (CNS), due to their infiltrative nature, tendency to recurrence, and poor response to treatments. Indeed, despite the advances in neurosurgical techniques and in radiation therapy, the modest effects of therapy are still challenging. Moreover, tumor recurrence is associated with the onset of therapy resistance; it is therefore critical to identify effective and well-tolerated pharmacological approaches capable of inducing durable responses in the appropriate patient groups. Molecular alterations of the RTK/PI3K/Akt/mTOR signaling pathway are typical hallmarks of glioma, and several clinical trials targeting one or more players of this axis have been launched, showing disappointing results so far, due to the scarce BBB permeability of certain compounds or to the occurrence of resistance/tolerance mechanisms. However, as RTK/PI3K/mTOR is one of the pivotal pathways regulating cell growth and survival in cancer biology, targeting still remains a strong rationale for developing strategies against gliomas. Future rigorous clinical studies, aimed at addressing the tumor heterogeneity, the interaction with the microenvironment, as well as diverse posology adjustments, are needed—which might unravel the therapeutic efficacy and response prediction of an RTK/PI3K/mTOR-based approach.

Development and in vivo assessment of a novel MRI‐compatible headframe system for the ovine animal model

The brain of sheep has primarily been used in neuroscience as an animal model because of its similarity to the human brain, in particular if compared to other models such as the lissencephalic rodent brain. Their brain size also makes sheep an ideal model for the development of neurosurgical techniques using conventional clinical CT/MRI scanners and stereotactic systems for neurosurgery. In this study, we present the design and validation of a new CT/MRI compatible head frame for the ovine model and software, with its assessment under two real clinical scenarios. Ex-vivo and in vivo trial results report an average linear displacement of the ovine head frame during conventional surgical procedures of 0.81mm for ex-vivo trials and 0.68mm for in vivo tests, respectively. These trial results demonstrate the robustness of the head frame system and its suitability to be employed within a real clinical setting.

Brain Functional Networks and Awake Craniotomy for Gliomas

The sophisticated functional networks of the human brain are integral to life, controlling domains such as language understanding and production and social cognition, which are important for inter-personal communication. Glioma, a primary brain tumor, infiltrates into the brain tissue, forcing the normal brain to reorganize the neural networks(brain plasticity)to resist the invasion. Awake craniotomy for gliomas enables reliable intraoperative identification and preservation of not only the innate normal brain functional areas but also the brain functional networks that have adapted and changed in response to the tumor-invasive environment. Recent advances in neurosurgical techniques and anesthetics have enabled the performance of intraoperative mapping of various brain functions, while maintaining the patient at a high level of awake condition. Attempts have also been made to preserve not only the language functions in the left cerebral hemisphere but also the higher brain functions represented by the right frontal lobe. Herein, we introduce the neural networks of the brain that glioma surgeons need to be aware of, and further describe the indications, methods, and usefulness of awake craniotomy for preserving these networks. In addition, we will discuss topics expected to become the standard in the near future.

Strategies for the Prevention of Complications in Brain Glioma Surgery

Introduction: Brain glioma is the most common and lethal primary malignant intracranial tumor. Nonetheless, gross tumor resection remains the most successful treatment modality, which may prolong progression free survival of these patients. However, excessive surgery brings a danger of neurological, regional and systemic complications, which may be diminished/ avoided by better pre- and intra-operative care and by modern neurosurgical techniques. Aim: To analyze the incidence and type of peri- and post-operative complications in surgical brain glioma patients. Computing the results, advice on complication prevention was made. Methods: A single institution series of brain glioma patients operated on during a two-year period was analyzed. The incidence, type and time of complications were observed, as well as the patients’ gender and age, and the extent of tumor resection complications, dichotomized as peri- and post-operative variables, were correlated with investigated parameters to find out their possible association. Results: Transitory neurological deficit was the most common peri-operative complication. Seizures, meningitis, and permanent neurological deficit were commonly recorded among post operative complications. Conclusion: Patients’ gender and age, and the extent of tumor resection were not influential to the development of brain glioma complications. Aggressive surgery requires the avoidance of complications by cautious patient selection, multidisciplinary preoperative planning, and scrupulous neurosurgical technique augmented by up-to-date armamentarium.

P51 External Ventricular Drainage Insertion Audit

IntroductionExternal Ventricular Drainage (EVD) is a neurosurgical technique used to lower the intercranial pressure while cerebrospinal fluid (CSF) flow is obstructed. The infection rate associated with the EVD insertion in the UK is 9.3%, with ventriculitis being the most common one. The aim of the audit was to compare our outcomes and infection rates and national standards and to implement an EVD Management protocol to improve patient outcome.MethodsThe data was collected from 43 patients, 98% of whom were emergency admitted cases. For all EVD procedures, silver coated catheters were used. The surgical factors such as the surgical team performance and the average operative time (1h 11min) were accounted for in the audit. The most common reason for EVD insertion was subarachnoid haemorrhage. Prophylactic antibiotics were administered in all cases before the surgery. 12% of the EVDs were used for Intercranial Pressure Monitoring.Results12% patients’ samples had catheter associated infections. The average EVD insertion period was 18 days. Leaks occurred in 11 cases (26%). 3 of them subsequently developed ventriculitis. White cell count result was over 10,000 cells per mm3 in 40% of patients.ConclusionsTwice longer sampling time then the national average (8 days) increased the number of ITU transfers. The cause would be the use of out-of-date EVD type. However, the silver impregnated lines versus non-impregnated have a lower cerebrospinal fluid infection rate, the bolt connected EVDs would be more precise and decrease the rate of resuturing and hence decrease a chance of CSF infection.

Cranioplasty Flap Lifting Caused by Intracranial Hypertension Literature Review

Cranioplasty is a neurosurgical technique that replaces a bone defect in the skull with hard replacement tissue. It is indicated in particular after a decompressive craniectomy performed in severe head trauma in order to control intracranial hypertension refractory to medical treatment. Cranioplasty is sometimes associated with a significant number of complications, including hydrocephalus. In this article, we report the case of a cranioplasty flap lifting on intracranial hypertension following postoperative hydrocephalus and discuss the clinical relevance with a review of the literature.

Deep Brain Stimulation for Alzheimer's Disease: Stimulation Parameters and Potential Mechanisms of Action

Deep brain stimulation (DBS) is a neurosurgical technique that regulates neuron activity by using internal pulse generators to electrodes in specific target areas of the brain. As a blind treatment, DBS is widely used in the field of mental and neurological diseases, although its mechanism of action is still unclear. In the past 10 years, DBS has shown a certain positive effect in animal models and patients with Alzheimer's disease (AD), but there are also different results that may be related to the stimulation parameters of DBS. Based on this, determining the optimal stimulation parameters for DBS in AD and understanding its mechanism of action are essential to promote the clinical application of DBS in AD. This review aims to explore the therapeutic effect of DBS in AD, and to analyze its stimulation parameters and potential mechanism of action. The keywords “Deep brain stimulation” and “Alzheimer's Disease” were used for systematic searches in the literature databases of Web of Science and PubMed (from 1900 to September 29, 2020). All human clinical studies and animal studies were reported in English, including individual case studies and long-term follow-up studies, were included. These studies described the therapeutic effects of DBS in AD. The results included 16 human clinical studies and 14 animal studies, of which 28 studies clearly demonstrated the positive effect of DBS in AD. We analyzed the current stimulation parameters of DBS in AD from stimulation target, stimulation frequency, stimulation start time, stimulation duration, unilateral/bilateral treatment and current intensity, etc., and we also discussed its potential mechanism of action from multiple aspects, including regulating related neural networks, promoting nerve oscillation, reducing β-amyloid and tau levels, reducing neuroinflammation, regulating the cholinergic system, inducing the synthesis of nerve growth factor.

Y-Box Binding Protein-1: A Neglected Target in Pediatric Brain Tumors?

Brain and central nervous system tumors represent the most common childhood solid tumors. Comprising 21% of all pediatric cancers, they remain the leading cause of cancer-related mortality and morbidity in childhood. Due to advances in neurosurgical technique, radiotherapy and the use of combination therapy, survival rates have generally increased. However, by cause of the lesion itself, its surgical removal and subsequent treatment, survivors are at high risk of long-term neurocognitive sequelae and secondary cancer. Clearly, improvements in diagnosis and treatment are needed. Accordingly, current treatment is evolving away from conventional, uniform therapy and towards risk-stratified regimens and molecularly-targeted therapies, with the aim of diminishing adverse side effects while minimizing the risk of disease recurrence. The multifunctional oncoprotein Y-box binding protein 1 (YB-1) may serve as one such molecular target. Increased YB-1 levels have been reported in a number of pediatric brain tumors, where YB-1 appears to facilitate the advancement of malignant phenotypes. These include proliferation, invasion, and resistance to therapy, as well as the maintenance of brain tumor-initiating cells. Here we evaluate the current literature and show how YB-1 modulates signaling pathways driving each of these phenotypes. We also review the regulation of YB-1 at a transcriptional, translational, posttranslational and subcellular level and argue that there is strong and sufficient evidence to support the development of YB-1 as a biomarker and future therapeutic target in childhood brain tumors.

Endoscopic versus Open Microsurgical Excision of Colloid Cysts: A Comparative Analysis and State-of-the-Art Review of Neurosurgical Techniques

The surgical approaches of colloid cysts commonly include endoscopy or open microsurgery. Each approach carries its own challenges, feasibility, and complications. The aim of the current study is to compare endoscopic versus open microsurgical excision of third ventricular colloid cysts. A retrospective cohort study was conducted to compare the surgical outcomes of endoscopic versus open microsurgical (transcortical-transventricular and transcallosal approaches) excision of colloid cyst of the third ventricle at a tertiary-care medical institute. All patients with a neuroradiologic diagnosis of colloid cyst who subsequently underwent surgical management between January 2003 and June 2020 were included. The neurologic outcome was assessed at the last follow-up visit. A total of 32 patients with colloid cysts were included in the study. The mean age was 35.8 ± 18.3 years (range, 4-75 years). Female patients slightly outnumbered male patients (n= 17; 53.1%). A total of 21 patients (65.6%) underwent endoscopic resection of the colloid cyst. Complications were encountered in 7 patients (endoscopic, n= 3; microsurgery, n= 4; P= 0.151). Recurrence was identified in 4 patients (endoscopic, n= 3; microsurgery, n= 1; P= 0.673). Most patients improved neurologically on follow-up visits to the clinic (endoscopic, n= 19; microsurgery, n= 9; P= 0.482). Both endoscopic and microsurgical approaches provide favorable surgical outcomes in colloid cyst resection. The complication rates between both approaches is statistically insignificant. The optimal surgical approach for colloid cyst resection remains controversial.

82 Neuroprotection is improved by watertightness of spina bifida repair in the fetal lamb

We investigated the neurofunctional consequences of the watertightness of prenatal spina bifida (SB)-repair in the fetal lamb model. The degree to which cerebrospinal fluid leakage (CSF) is prevented by the neurosurgical technique may translate to the way fetal SB-repair is done clinically. Neurological outcomes of watertight and non-watertight multilayer repairs were compared to those in unrepaired lambs. 75-day fetal lambs (term=145 days) underwent standardized induction of lumbar SB. At 100 days, they were assigned to one of the three groups. At 1-2 days after term delivery, we assessed hindbrain herniation (HH)-reversal on magnetic resonance imaging as primary outcome measure. Secondary proxies of neuroprotection were CSF-leakage at the repair site; hindlimb function based on joint movement score, locomotor grade, Motor and Somatosensory Evoked Potentials; neuroprotection (i.e. score of 4/4 encompassing live birth, HH-reversal, absent CSF-leakage, joint score ≥9/15), and brain and spinal cord histology. Compared to unrepaired lambs, watertight repair was neuroprotective in 5/7 lambs, as evidenced by a 100% HH-reversal, lower CSF-leakage rate (14%), better hindlimb motor function, higher neuronal density in the hippocampus and corpus callosum, and larger area of astroglial cells at the lesion epicenter (Table 1). Conversely, non-watertight SB-repair did not achieve the same level of neuroprotection (1/7), i.e. 86% HH-reversal rate, no motor function improvement, high CSF-leakage rate (43%), low brain neuron count and astroglial cell area. These findings demonstrate that a watertight fetal SB-repair improves brain and spinal cord structure and function more. This has important clinical implication and neurosurgical technique that achieves watertightness should be adopted.