Toward the "Perfect" Shunt: Historical Vignette, Current Efforts, and Future Directions.

As a concept, drainage of excess fluid volume in the cranium has been around for more than 1000 years. Starting with the original decompression-trepanation of Abulcasis to modern programmable shunt systems, to other nonshunt-based treatments such as endoscopic third ventriculostomy and choroid plexus cauterization, we have come far as a field. However, there are still fundamental limitations that shunts have yet to overcome: namely posture-induced over- and underdrainage, the continual need for valve opening pressure especially in pediatric cases, and the failure to reinstall physiologic intracranial pressure dynamics. However, there are groups worldwide, in the clinic, in industry, and in academia, that are trying to ameliorate the current state of the technology within hydrocephalus treatment. This chapter aims to provide a historical overview of hydrocephalus, current challenges in shunt design, what members of the community have done and continue to do to address these challenges, and finally, a definition of the "perfect" shunt is provided and how the authors are working toward it.

The modulatory effect of self-paced and cued motor execution on subthalamic beta-bursts in Parkinson's disease: Evidence from deep brain recordings in humans.

Deep brain stimulation (DBS) electrodes provide an unparalleled window to record and investigate neuronal activity right at the core of pathological brain circuits. In Parkinson's disease (PD), basal ganglia beta-oscillatory activity (13-35 Hz) seems to play an outstanding role. Conventional DBS, which globally suppresses beta-activity, does not meet the requirements of a targeted treatment approach given the intricate interplay of physiological and pathological effects of beta-frequencies. Here, we wanted to characterise the local field potential (LFP) in the subthalamic nucleus (STN) in terms of beta-burst prevalence, amplitude and length between movement and rest as well as during self-paced as compared to goal-directed motor control. Our electrophysiological recordings from externalised DBS-electrodes in nine patients with PD showed a marked decrease in beta-burst durations and prevalence during movement as compared to rest as well as shorter and less frequent beta-bursts during cued as compared to self-paced movements. These results underline the importance of beta-burst modulation in movement generation and are in line with the clinical observation that cued motor control is better preserved than self-paced movements. Furthermore, our findings motivate the use of adaptive DBS based on beta-bursts, which selectively trim longer beta-bursts, as it is more suitable and efficient over a range of motor behaviours than conventional DBS.

Air travel with pneumocephalus: a systematic review.

INTRODUCTION: Concerns arise when patients with pneumocephalus engage in air travel. How hypobaric cabin pressure affects intracranial air is largely unclear. A widespread concern is that the intracranial volume could relevantly expand during flight and lead to elevated intracranial pressure. The aim of this systematic review was to identify and summarise models and case reports with confirmed pre-flight pneumocephalus. METHODS: The terms (pneumocephalus OR intracranial air) AND (flying OR fly OR travel OR air transport OR aircraft) were used to search the database PubMed on 30 November 2021. This search returned 144 results. To be included, a paper needed to fulfil each of the following criteria: (i) peer-reviewed publication of case reports, surveys, simulations or laboratory experiments that focussed on air travel with pre-existing pneumocephalus; (ii) available in full text. RESULTS: Thirteen studies met the inclusion criteria after title or abstract screening. We additionally identified five more articles when reviewing the references. A notion that repeatedly surfaced is that any air contained within the neurocranium increases in volume at higher altitude, much like any extracranial gas, potentially resulting in tension pneumocephalus or increased intracranial pressure. DISCUSSION: Relatively conservative thresholds for patients flying with pneumocephalus are suggested based on models where the intracranial air equilibrates with cabin pressure, although intracranial air in a confined space would be surrounded by the intracranial pressure. There is a discrepancy between the models and case presentations in that we found no reports of permanent or transient decompensation secondary to a pre-existing pneumocephalus during air travel. Nevertheless, the quality of examination varies and clinicians might tend to refrain from reporting adverse events. We identified a persistent extracranial to intracranial fistulous process in multiple cases with newly diagnosed pneumocephalus after flight. Finally, we summarised management principles to avoid complications from pneumocephalus during air travel and argue that a patient-specific understanding of the pathophysiology and time course of the pneumocephalus are potentially more important than its volume.

Mobile intraoperative CT-assisted frameless stereotactic biopsies achieved single-millimeter trajectory accuracy for deep-seated brain lesions in a sample of 7 patients.

BACKGROUND: Brain biopsies are crucial diagnostic interventions, providing valuable information for treatment and prognosis, but largely depend on a high accuracy and precision. We hypothesized that through the combination of neuronavigation-based frameless stereotaxy and MRI-guided trajectory planning with intraoperative CT examination using a mobile unit, one can achieve a seamlessly integrated approach yielding optimal target accuracy. METHODS: We analyzed a total of 7 stereotactic biopsy trajectories for a variety of deep-seated locations and different patient positions. After rigid head fixation, an intraoperative pre-procedural scan using a mobile CT unit was performed for automatic image fusion with the planning MRI images and a peri-procedural scan with the biopsy cannula in situ for verification of the definite target position. We then evaluated the radial trajectory error. RESULTS: Intraoperative scanning, surgery, computerized merging of MRI and CT images as well as trajectory planning were feasible without difficulties and safe in all cases. We achieved a radial trajectory deviation of 0.97 ± 0.39 mm at a trajectory length of 60 ± 12.3 mm (mean ± standard deviation). Repositioning of the biopsy cannula due to inaccurate targeting was not required. CONCLUSION: Intraoperative verification using a mobile CT unit in combination with frameless neuronavigation-guided stereotaxy and pre-operative MRI-based trajectory planning was feasible, safe and highly accurate. The setting enabled single-millimeter accuracy for deep-seated brain lesions and direct detection of intraoperative complications, did not depend on a dedicated operating room and was seamlessly integrated into common stereotactic procedures.

An unexpected intracerebral lesion - case report of a superinfected aspergillosis mimicking a brain metastasis.

BACKGROUND: Invasive aspergillosis of the central nervous system is a rare but increasingly prevalent disease. We present the unusual case of an immunosuppressed patient suffering from unexpected superinfected invasive aspergillosis with cerebral, pulmonal, and adrenal manifestations, mimicking a metastasized bronchial carcinoma. This report reveals the importance of including aspergillosis in the differential diagnosis of a cerebral mass lesion in the light of unspecific clinical findings. CASE PRESENTATION: A 58-year-old immunocompromised female presented to our emergency department with a single tonic-clonic seizure. Imaging showed a ring enhancing cerebral mass with perifocal edema and evidence of two smaller additional hemorrhagic cerebral lesions. In the setting of a mass lesion in the lung, and additional nodular lesions in the left adrenal gland the diagnosis of a metastasized bronchus carcinoma was suspected and the cerebral mass resected. However, histology did not reveal any evidence for a neoplastic lesion but septate hyphae consistent with aspergillus instead and microbiological cultures confirmed concomitant staphylococcal infection. CONCLUSIONS: A high index of suspicion for aspergillus infection should be maintained in the setting of immunosuppression. Clinical and radiological findings are often unspecific and even misleading. Definite confirmation usually relies on tissue diagnosis with histochemical stains. Surgical resection is crucial for establishing the diagnosis and guiding therapy with targeted antifungal medications.

A stereotactic frame-based drill guide-aided setting for laser interstitial thermal therapy.

BACKGROUND: Magnetic resonance imaging (MRI)-guided laser interstitial thermal therapy (MRIgLITT) was demonstrated to be a viable neurosurgical tool. Apart from its variety of indications, different operative and technical nuances exist. In the present report, for the first time, the use and ability of a traditional Riechert-Mundinger (RM) stereotactic system combined with a novel drill guide kit for MRIgLITT are described. METHODS: A stereotactic frame-based setting was developed by combining an RM system with a drill guide kit and centering bone anchor screwing aid for application together with an MRIgLITT neuro-accessory kit and cooled laser applicator system. The apparatus was used for stereotactic biopsy and consecutive MRIgLITT with an intraoperative high-field MRI scanner in a brain tumor case. RESULTS: The feasibility of an RM stereotactic apparatus and a drill guide kit for MRIgLITT was successfully assessed. Both stereotactic biopsy and subsequent MRIgLITT in a neurooncological patient could easily and safely be performed. No technical problems or complications were observed. CONCLUSION: The combination of a traditional RM stereotactic system, a new drill guide tool, and intraoperative high-field MRI provides neurosurgeons with the opportunity to reliably confirm the diagnosis by frame-based biopsy and allows for stable and accurate real-time MRIgLITT.

How to avoid pneumocephalus in deep brain stimulation surgery? Analysis of potential risk factors in a series of 100 consecutive patients.

BACKGROUND: Accuracy of lead placement is the key to success in deep brain stimulation (DBS). Precise anatomic stereotactic planning usually is based on stable perioperative anatomy. Pneumocephalus due to intraoperative CSF loss is a common procedure-related phenomenon which could lead to brain shift and targeting inaccuracy. The aim of this study was to evaluate potential risk factors of pneumocephalus in DBS surgery. METHODS: We performed a retrospective single-center analysis in patients undergoing bilateral DBS. We quantified the amount of pneumocephalus by postoperative CT scans and corrected the data for accompanying brain atrophy by an MRI-based score. Automated computerized segmentation algorithms from a dedicated software were used. As potential risk factors, we evaluated the impact of trephination size, the number of electrode tracks, length of surgery, intraoperative blood pressure, and brain atrophy. RESULTS: We included 100 consecutive patients that underwent awake DBS with intraoperative neurophysiological testing. Systolic and mean arterial blood pressure showed a substantial impact with an inverse correlation, indicating that lower blood pressure is associated with higher volume of pneumocephalus. Furthermore, the length of surgery was clearly correlated to pneumocephalus. CONCLUSION: Our analysis identifies intraoperative systolic and mean arterial blood pressure as important risk factors for pneumocephalus in awake stereotactic surgery.

sEVD-smartphone-navigated placement of external ventricular drains.

BACKGROUND: Currently, the trajectory for insertion of an external ventricular drain (EVD) is mainly determined using anatomical landmarks. However, non-assisted implantations frequently require multiple attempts and are associated with EVD malpositioning and complications. The authors evaluated the feasibility and accuracy of a novel smartphone-guided, angle-adjusted technique for assisted implantations of an EVD (sEVD) in both a human artificial head model and a cadaveric head. METHODS: After computed tomography (CT), optimal insertion angles and lengths of intracranial trajectories of the EVDs were determined. A smartphone was calibrated to the mid-cranial sagittal line. Twenty EVDs were placed using both the premeasured data and smartphone-adjusted insertion angles, targeting the center of the ipsilateral ventricular frontal horn. The EVD positions were verified with post-interventional CT. RESULTS: All 20 sEVDs (head model, 8/20; cadaveric head, 12/20) showed accurate placement in the ipsilateral ventricle. The sEVD tip locations showed a mean target deviation of 1.73° corresponding to 12 mm in the plastic head model, and 3.45° corresponding to 33 mm in the cadaveric head. The mean duration of preoperative measurements on CT data was 3 min, whereas sterile packing, smartphone calibration, drilling, and implantation required 9 min on average. CONCLUSIONS: By implementation of an innovative navigation technique, a conventional smartphone was used as a protractor for the insertion of EVDs. Our ex vivo data suggest that smartphone-guided EVD placement offers a precise, rapidly applicable, and patient-individualized freehand technique based on a standard procedure with a simple, cheap, and widely available multifunctional device.

Introduction of a self-holding retractor for optimized abdominal visualization in ventriculoperitoneal shunt surgery: first experiences at a single center.

OBJECTIVE: Ventriculoperitoneal shunt implantation is a common procedure in general neurosurgery. The patient population is often fragile, ranging from elderly to pediatric patients, and avoidance of perioperative complication is of utmost importance. Abdominal catheter dislocation has been found to be a common cause for early shunt dysfunction and needs to be avoided by optimal visualization of the abdominal catheter insertion zone. Here, we introduce a self-holding wound retractor system Alexis® and demonstrate its use for abdominal shunt surgery in a series of patients. METHODS: We explain the use of the Alexis® self-holding wound retractor during open ventriculoperitoneal shunt surgery in a series of 16 patients operated at our institution. RESULTS: The self-holding retractor consists of two polymer rings connected by a polymer membrane. The deep ring is easily placed on the internal fascia of the straight muscle and circular retraction is achieved by twisting the upper ring. Free hand working can then be performed by a single surgeon with good abdominal exposure. No case of abdominal dislocation or infection occurred in our series, although no properly powered statistical analysis can be performed regarding the sample size. CONCLUSION: We demonstrate the Alexis® Wound Retractor, which is an easy tool for optimal visualization of the abdominal catheter insertion zone. We believe it can facilitate surgical practice of shunt surgery, especially in obese patients.

Directional local field potentials: A tool to optimize deep brain stimulation.

BACKGROUND: Although recently introduced directional DBS leads provide control of the stimulation field, programing is time-consuming. OBJECTIVES: Here, we validate local field potentials recorded from directional contacts as a predictor of the most efficient contacts for stimulation in patients with PD. METHODS: Intraoperative local field potentials were recorded from directional contacts in the STN of 12 patients and beta activity compared with the results of the clinical contact review performed after 4 to 7 months. RESULTS: Normalized beta activity was positively correlated with the contact's clinical efficacy. The two contacts with the highest beta activity included the most efficient stimulation contact in up to 92% and that with the widest therapeutic window in 74% of cases. CONCLUSION: Local field potentials predict the most efficient stimulation contacts and may provide a useful tool to expedite the selection of the optimal contact for directional DBS. © 2017 The Authors. Movement Disorders published by Wiley Periodicals, Inc. on behalf of International Parkinson and Movement Disorder Society.

Deep Brain Stimulation for Tremor: Is There a Common Structure?

BACKGROUND: Subthalamic nucleus (STN) stimulation has been recognized to control resting tremor in Parkinson disease. Similarly, thalamic stimulation (ventral intermediate nucleus; VIM) has shown tremor control in Parkinson disease, essential, and intention tremors. Recently, stimulation of the posterior subthalamic area (PSA) has been associated with excellent tremor control. Thus, the optimal site of stimulation may be located in the surrounding white matter. AIMS: The objective of this work was to investigate the area of stimulation by determining the contact location correlated with the best tremor control in STN/VIM patients. METHODS: The mean stimulation site and related volume of tissue activated (VTA) of 25 tremor patients (STN or VIM) were projected on the Morel atlas and compared to stimulation sites from other tremor studies. RESULTS: All patients showed a VTA that covered ≥50% of the area superior and medial to the STN or inferior to the VIM. Our stimulation areas suggest involvement of the more lateral and superior part of the dentato-rubro-thalamic tract (DRTT), whereas targets described in other studies seem to involve the DRTT in its more medial and inferior part when it crosses the PSA. CONCLUSIONS: According to anatomical and diffusion tensor imaging data, the DRTT might be the common structure stimulated at different portions within the PSA/caudal zona incerta.

Combined thalamic and subthalamic deep brain stimulation for tremor-dominant Parkinson's disease.

Deep brain stimulation (DBS) in the thalamic ventral intermediate (Vim) or the subthalamic nucleus (STN) reportedly improves medication-refractory Parkinson's disease (PD) tremor. However, little is known about the potential synergic effects of combined Vim and STN DBS. We describe a 79-year-old man with medication-refractory tremor-dominant PD. Bilateral Vim DBS electrode implantation produced insufficient improvement. Therefore, the patient underwent additional unilateral left-sided STN DBS. Whereas Vim or STN stimulation alone led to partial improvement, persisting tremor resolution occurred after simultaneous stimulation. The combination of both targets may have a synergic effect and is an alternative option in suitable cases.

Directional deep brain stimulation: an intraoperative double-blind pilot study.

Deep brain stimulation of different targets has been shown to drastically improve symptoms of a variety of neurological conditions. However, the occurrence of disabling side effects may limit the ability to deliver adequate amounts of current necessary to reach the maximal benefit. Computed models have suggested that reduction in electrode size and the ability to provide directional stimulation could increase the efficacy of such therapies. This has never been demonstrated in humans. In the present study, we assess the effect of directional stimulation compared to omnidirectional stimulation. Three different directions of stimulation as well as omnidirectional stimulation were tested intraoperatively in the subthalamic nucleus of 11 patients with Parkinson's disease and in the nucleus ventralis intermedius of two other subjects with essential tremor. At the trajectory chosen for implantation of the definitive electrode, we assessed the current threshold window between positive and side effects, defined as the therapeutic window. A computed finite element model was used to compare the volume of tissue activated when one directional electrode was stimulated, or in case of omnidirectional stimulation. All but one patient showed a benefit of directional stimulation compared to omnidirectional. A best direction of stimulation was observed in all the patients. The therapeutic window in the best direction was wider than the second best direction (P = 0.003) and wider than the third best direction (P = 0.002). Compared to omnidirectional direction, the therapeutic window in the best direction was 41.3% wider (P = 0.037). The current threshold producing meaningful therapeutic effect in the best direction was 0.67 mA (0.3-1.0 mA) and was 43% lower than in omnidirectional stimulation (P = 0.002). No complication as a result of insertion of the directional electrode or during testing was encountered. The computed model revealed a volume of tissue activated of 10.5 mm(3) in omnidirectional mode, compared with 4.2 mm(3) when only one electrode was used. Directional deep brain stimulation with a reduced electrode size applied intraoperatively in the subthalamic nucleus as well as in the nucleus ventralis intermedius of the thalamus significantly widened the therapeutic window and lowered the current needed for beneficial effects, compared to omnidirectional stimulation. The observed side effects related to direction of stimulation were consistent with the anatomical location of surrounding structures. This new approach opens the door to an improved deep brain stimulation therapy. Chronic implantation is further needed to confirm these findings.

Can in-vitro chemoresponse assays help find new treatment regimens for malignant gliomas?

Various in-vitro chemosensitivity and resistance assays (CSRAs) have been demonstrated to be helpful decision aids for non-neurological tumors. Here, we evaluated the performance characteristics of two CSRAs for glioblastoma (GB) cells. The chemoresponse of fresh GB cells from 30 patients was studied in vitro using the ATP tumor chemoresponse assay and the chemotherapy resistance assay (CTR-Test). Both assay platforms provided comparable results. Of seven different chemotherapeutic drugs and drug combinations tested in vitro, treosulfan plus cytarabine (TARA) was the most effective, followed by nimustine (ACNU) plus teniposide (VM26) and temozolomide (TMZ). Whereas ACNU/VM26 and TMZ have proven their clinical value for malignant gliomas in large randomized studies, TARA has not been successful in newly diagnosed gliomas. This seeming discrepancy between in vitro and clinical result might be explained by the pharmacological behavior of treosulfan. Our results show reasonable agreement between two cell-based CSRAs. They appear to confirm the clinical effectiveness of drugs used in GB treatment as long as pharmacological preconditions such as overcoming the blood-brain barrier are properly considered.

Neurofeedback-enabled beta power control with a fully implanted DBS system in patients with Parkinson's disease.

OBJECTIVE: Parkinsonian motor symptoms are linked to pathologically increased beta oscillations in the basal ganglia. Studies with externalised deep brain stimulation electrodes showed that Parkinson patients were able to rapidly gain control over these pathological basal ganglia signals through neurofeedback. Studies with fully implanted deep brain stimulation systems duplicating these promising results are required to grant transferability to daily application. METHODS: In this study, seven patients with idiopathic Parkinson's disease and one with familial Parkinson's disease were included. In a postoperative setting, beta oscillations from the subthalamic nucleus were recorded with a fully implanted deep brain stimulation system and converted to a real-time visual feedback signal. Participants were instructed to perform bidirectional neurofeedback tasks with the aim to modulate these oscillations. RESULTS: While receiving regular medication and deep brain stimulation, participants were able to significantly improve their neurofeedback ability and achieved a significant decrease of subthalamic beta power (median reduction of 31% in the final neurofeedback block). CONCLUSION: We could demonstrate that a fully implanted deep brain stimulation system can provide visual neurofeedback enabling patients with Parkinson's disease to rapidly control pathological subthalamic beta oscillations. SIGNIFICANCE: Fully-implanted DBS electrode-guided neurofeedback is feasible and can now be explored over extended timespans.

A Soft Robotic Actuator System for In Vivo Modeling of Normal Pressure Hydrocephalus.

OBJECTIVE: The intracranial pressure (ICP) affects the dynamics of cerebrospinal fluid (CSF) and its waveform contains information that is of clinical importance in medical conditions such as hydrocephalus. Active manipulation of the ICP waveform could enable the investigation of pathophysiological processes altering CSF dynamics and driving hydrocephalus. METHODS: A soft robotic actuator system for intracranial pulse pressure amplification was developed to model normal pressure hydrocephalus in vivo. Different end actuators were designed for intraventricular implantation and manufactured by applying cyclic tensile loading on soft rubber tubing. Their mechanical properties were investigated, and the type that achieved the greatest pulse pressure amplification in an in vitro simulator of CSF dynamics was selected for application in vivo. A hydraulic actuation device based on a linear voice coil motor was developed to enable automated and fast operation of the end actuators. The combined system was validated in an acute ovine pilot in vivo study. RESULTS: in vitro results show that variations in the used materials and manufacturing settings altered the end actuator's dynamic properties, such as the pressure-volume characteristics. In the in vivo model, a cardiac-gated actuation volume of 0.125 mL at a heart rate of 62 bpm caused an increase of 205% in mean peak-to-peak amplitude but only an increase of 1.3% in mean ICP. CONCLUSION: The introduced soft robotic actuator system is capable of ICP waveform manipulation. SIGNIFICANCE: Continuous amplification of the intracranial pulse pressure could enable in vivo modeling of normal pressure hydrocephalus and shunt system testing under pathophysiological conditions to improve therapy for hydrocephalus.

Early major fracture care in polytrauma-priorities in the context of concomitant injuries: A Delphi consensus process and systematic review.

BACKGROUND: The timing of major fracture care in polytrauma patients has a relevant impact on outcomes. Yet, standardized treatment strategies with respect to concomitant injuries are rare. This study aims to provide expert recommendations regarding the timing of major fracture care in the presence of concomitant injuries to the brain, thorax, abdomen, spine/spinal cord, and vasculature, as well as multiple fractures. METHODS: This study used the Delphi method supported by a systematic review. The review was conducted in the Medline and EMBASE databases to identify relevant literature on the timing of fracture care for patients with the aforementioned injury patterns. Then, consensus statements were developed by 17 international multidisciplinary experts based on the available evidence. The statements underwent repeated adjustments in online- and in-person meetings and were finally voted on. An agreement of ≥75% was set as the threshold for consensus. The level of evidence of the identified publications was rated using the GRADE approach. RESULTS: A total of 12,476 publications were identified, and 73 were included. The majority of publications recommended early surgery (47/73). The threshold for early surgery was set within 24 hours in 45 publications. The expert panel developed 20 consensus statements and consensus >90% was achieved for all, with 15 reaching 100%. These statements define conditions and exceptions for early definitive fracture care in the presence of traumatic brain injury (n = 5), abdominal trauma (n = 4), thoracic trauma (n = 3), multiple extremity fractures (n = 3), spinal (cord) injuries (n = 3), and vascular injuries (n = 2). CONCLUSION: A total of 20 statements were developed on the timing of fracture fixation in patients with associated injuries. All statements agree that major fracture care should be initiated within 24 hours of admission and completed within that timeframe unless the clinical status or severe associated issues prevent the patient from going to the operating room. LEVEL OF EVIDENCE: Delphi-Consensus/Systematic Review; Level IV.

The influence of upright posture on craniospinal, arteriovenous, and abdominal pressures in a chronic ovine in-vivo trial.

INTRODUCTION: Most investigations into postural influences on craniospinal and adjacent physiology have been performed in anesthetized animals. A comprehensive study evaluating these physiologies while awake has yet been completed. METHODS: Six awake sheep had telemetric pressure sensors (100 Hz) implanted to measure intracranial, intrathecal, arterial, central venous, cranial, caudal, dorsal, and ventral intra-abdominal pressure (ICP, ITP, ABP, CVP, IAPcr, IAPcd, IAPds, IAPve, respectively). They were maneuvered upright by placing in a chair for two minutes; repeated 25 times over one month. Changes in mean and pulse pressure were calculated by comparing pre-chair, P0, with three phases during the maneuver: P1, chair entrance; P2, chair halftime; P3, prior to chair exit. Statistical significance (p ≤ .05) was assessed using repeated measures ANOVA. RESULTS: Significant mean pressure changes of (P1 - P0) and (P3 - P0) were measured at - 12.1 ± 3.1 and - 14.2 ± 3.0(p < .001), 40.8 ± 10.5 and 37.7 ± 3.5(p = .019), 9.7 ± 8.3 and 6.2 ± 5.3(p = .012), 22.3 ± 29.8 and 12.5 ± 12.1(p = .042), and 11.7 ± 3.9 and 9.0 ± 5.2(p = .014) mmHg, for ICP, ITP, IAPds, IAPcr, IAPca, respectively. For pulse pressures, significant changes of (P1 - P0) and (P3 - P0) were measured at - 1.3 ± 0.7 and - 2.0 ± 1.1(p < .001), 4.7 ± 2.3 and 1.4 ± 1.4(p < .001), 15.0 ± 10.2 and 7.3 ± 5.5(p < .001), - 0.7 ± 1.8 and - 1.7 ± 1.7(p < .001), - 1.3 ± 4.2 and - 1.4 ± 4.7(p = .006), and 0.3 ± 3.9 and - 1.0 ± 1.3(p < .001) mmHg, for ICP, ITP, ABP, IAPds, IAPcr, IAPca, respectively. CONCLUSIONS: Pressures changed posture-dependently to differing extents. Changes were most pronounced immediately after entering upright posture (P1) and became less prominent over the chair duration (P2-to-P3), suggesting increased physiologic compensation. Dynamic changes in IAP varied across abdominal locations, motivating the abdominal cavity not to be considered as a unified entity, but sub-compartments with individual dynamics.

Laser interstitial thermal therapy in pediatric cerebellar epilepsy.

Cerebellar lesional epilepsy is rare, commonly manifesting in early life and posing diagnostic and treatment challenges. Seizure semiology may be subtle, with repetitive eye blinking, face twitching, and irregular breathing, while EEG commonly remains unremarkable. Pharmacoresistance is the rule, and surgical intervention is the only treatment with the potential for cure. Novel minimally invasive techniques, such as laser interstitial thermal therapy (LITT), are emerging for surgically less accessible, deep-seated epileptogenic lesions. We report the case of a patient who presented with peculiar eye and face movements occurring episodically and stereotypically since the first weeks of life and was later diagnosed with cerebellar epilepsy related to a hamartoma. Refractory daily seizures, unresponsive to antiseizure medication, were followed by increasingly prominent gait ataxia and delayed speech development. Staged LITT was performed in two consecutive sessions at 3 and 4 years, leading to seizure cessation, neurological improvement, and developmental gains over a postsurgical follow-up period of 8 months. Our case highlights cerebellar lesional epilepsy as a rare but important differential diagnosis in children with paroxysmal disorders predominantly involving the face. Furthermore, we illustrate the radiological correlates of neurocognitive deficit related to the cerebellar lesion, manifesting as cerebello-cerebral diaschisis. Most importantly, our observations showcase LITT as a safe and effective therapeutic approach in cerebellar lesional epilepsy and an attractive alternative to open brain surgery, especially for deep-seated lesions in the pediatric population.

Impact of target depth on safety and efficacy outcomes in MR-guided focused ultrasound thalamotomy for tremor patients.

OBJECTIVE: Target depth, defined by the z-coordinate in the dorsoventral axis relative to the anterior commissure-posterior commissure axial plane of the MR-guided focused ultrasound (MRgFUS) lesion, is considered to be critical for tremor improvement and the occurrence of side effects such as gait impairment. However, although different z-coordinates are used in the literature, there are no comparative studies available with information on optimal lesion placement. This study aimed to compare two different MRgFUS lesion targets (z = +2 mm vs z = 0 mm) regarding efficacy and safety outcomes. METHODS: The authors conducted a retrospective analysis of 52 patients with pharmacoresistant tremor disorders who received unilateral MRgFUS thalamotomy in the ventral intermediate nucleus for the first time between 2017 and 2022 by one neurosurgeon, with two different z-coordinates, either z = +2 mm (+2-mm group; n = 17) or z = 0 mm (0-mm group; n = 35), but otherwise identical parameters. Standardized video-recorded assessments of efficacy (including the Washington Heights-Inwood Genetic Study of Essential Tremor scale) and safety (using a standardized grading system) outcomes at baseline and at 6 months posttreatment were reviewed and compared. Moreover, overall patient satisfaction was extracted as documented by the examiner at 6 months. RESULTS: Based on a multiple logistic regression analysis, the authors found that a more dorsal target with a z-coordinate of +2 mm as compared with 0 mm was associated with a higher incidence of any persistent side effect at 6 months (p = 0.02). Most consistently, sensory disturbances, although mild and nondisturbing in most cases, occurred more frequently in the +2-mm group (35% vs 11%, p = 0.007), while no significant differences were found for gait impairment (29% vs 35%) and arm ataxia (24% vs 11%). On the other hand, average tremor suppression was similar (63.6% vs 60.2%) between the groups. Here, higher efficacy was associated with a higher side effect burden in the 0-mm group but not in the +2-mm group. Despite the occurrence of side effects, general patient satisfaction was high (87% would undergo MRgFUS again) as most patients valued tremor suppression more. CONCLUSIONS: A more ventral MRgFUS target of z = 0 mm seems to be associated with a more favorable safety and a comparable efficacy profile as compared with a more dorsal target of z = +2 mm, but prospective studies are warranted.