The prepontine block and its relevance for the development and treatment of hydrocephalus.

OBJECTIVE: Pulsatile CSF flow patterns include flow through the ventricles to the subarachnoid space and cisterns and from the infra- to the supratentorial subarachnoid space. In this study, we demonstrate how an obstruction at the level of the prepontine space may lead to obstructive hydrocephalus with specific radiological characteristics, as well as the implications for treatment options. METHODS: We retrospectively collected data of patients who underwent surgery between February 2010 and December 2022 for hydrocephalus secondary to a suspected prepontine block. One additional patient diagnosed with prepontine block who did not undergo surgery was also included. We excluded patients with a background of previous unrelated neurosurgical procedures or CNS infections. RESULTS: Six children and two adults were included. Three presented with hydrocephalus on imaging, without any other underlying pathology. Five had a suprasellar arachnoid cyst, with its lower border abating the pons and occluding the spinal subarachnoid space (SAS). All cases had an open aqueduct on T2 sagittal sequences, as well as an infracerebellar or retrocerebellar CSF collection. In most cases, a horizontal web was identified in the prepontine region. Seven cases were treated with an endoscopic fenestration. One patient subsequently underwent a shunt surgery. All the operated children reached normal developmental milestones after surgery. CONCLUSIONS: This paper describes a rather small series of cases where clear obstruction was observed at the level of the prepontine subarachnoid space. We believe this anatomical subtlety adds to a better understanding of CSF pathways and the role of ETV in treating hydrocephalus, focusing on a small subgroup of patients without a clear obstruction.

Pineal region tumors: an entity with crucial anatomical nuances.

PURPOSE: Intra-axial "pineal region" tumors include pineal, tectal, and aqueductal tumors. All three tumor subgroups cause obstruction of the aqueduct; however, they differ in radiological nuances, pathology, differential diagnosis, and treatment. The goal of this manuscript is to describe the radiological, clinical, and pathological nuances that differentiate between these subgroups. METHODS: All patients with intra-axial pineal region tumors were analyzed retrospectively, including demographics, radiological characteristics, pathology, treatment, and outcome. RESULTS: Forty-nine patients (1-69 years of age) were included: 19 pineal, 10 tectal, 10 aqueductal, 4 periaqueductal, and 6 complex. The 3 main subgroups differed in various radiological and anatomical nuances. Age and gender did not differ between groups. Other factors that did not differ between groups included T1 and T2 signals, presence of blood products, a normally located (non-displaced) tectum, anterior tectal displacement, thalamic involvement, and presence of hydrocephalus. The pathological spectrum differed between the 3 main subgroups, as well as the surgical treatment, and outcome. CONCLUSIONS: Despite sharing a close anatomical location, as well as all causing obstruction of the aqueduct with secondary hydrocephalus, the differential diagnosis, diagnostic methods, and possible treatment and surgical options differ between the various subgroups. Anatomical nuances are described to better delineate the various tumor subgroups and recommend specific treatment approaches.

The role of ICP monitoring in paediatric IIH.

INTRODUCTION: Diagnosis of idiopathic intracranial hypertension (IIH) in children is an extrapolation of the guidelines suggested for adult population. Lumbar puncture (LP) plays a crucial role in the diagnosis. The diagnosis of IIH at times is solely dependent on the interpretation of the opening pressure (OP). Unfortunately, LP-OP can vary due circumstantial parameters and therefore may be an unreliable form of intracranial pressure (ICP) measurement. Confirming the diagnosis based (as suggested by guidelines) on LP-OP in a doubtful clinical situation would be inappropriate. The aim of our study was to analyse the reliability of LP-OP and importance of ICP monitoring in situations where diagnosis of IIH was questionable. METHODS: Retrospective review of all children with diagnosis of IIH over a 10-year period was conducted. Children who underwent ICP monitoring (ICPM) were selected. We considered 2 LP-OP values-last LP (lLP) and the mean LP (mLP) for analysis. ICPM and LP-OP were compared. Follow-up till last clinic visit was also considered for long-term outcome. RESULTS: Eleven children (male 3; female 8) were included in the study. Mean delay between LP and ICPM was 112.8 days (17-257 days). There was lack of correlation between LP-OP and ICP in 9 children. ICP monitoring refuted the diagnosis of IIH in 80% of children and prevented exposure to unnecessary medical and surgical intervention. There was 1complication with ICPM. In 90% of children, there was no progression of symptoms following a decision based on ICP monitoring on long-term follow-up (mean, 36.5 months). CONCLUSION: When the diagnosis of IIH is in doubt, LP may be unreliable and formal ICP monitoring is advised.

Dynamic assessment of venous anatomy and function in neurosurgery with real-time intraoperative multimodal ultrasound: technical note.

The relevance of the cerebral venous system is often underestimated during neurosurgical procedures. Damage to this draining system can have catastrophic implications for the patient. Surgical decision-making and planning must consider each component of the venous compartment, from the medullary draining vein to the dural sinuses and extracranial veins. Intraoperative ultrasound (ioUS) permits the real-time study of venous compartments using different modalities, thus allowing complete characterization of their anatomical and functional features. The B-mode (brightness mode) offers a high-resolution anatomical representation of veins and their relationships with lesions. Doppler modalities (color, power, spectral) allow the study of blood flow and identification of vessels to distinguish their functional characteristics. Contrast-enhanced US allows one to perform real-time angiosonography showing both the functional and the anatomical aspects of vessels. In this technical report, the authors demonstrate the different applications of multimodal ioUS in neurosurgery for identifying the anatomical and functional characteristics of the venous compartment. They discuss the general principles and technical nuances of ioUS and analyze their potential implications for the study of various venous districts during neurosurgical procedures.

E-Bikes (Electrical Bicycles and Scooters) Related Neurosurgical Injuries in the Adult Population: A Single-Center Experience.

E-bikes (electrical bicycles and scooters) have been increasingly used as a means of transportation, especially among young adults. E-bikers have more accidents, at higher velocities and more severe kinematics, increasing the rate of neurosurgical injuries. Severe neurosurgical injury patterns result in significant morbidity and mortality. We collected data regarding adult patients (>18 years old), who suffered e-bike-related neurosurgical injuries, in a single tertiary medical center in Israel, between July 2019 and June 2020. Fifty-eight consecutive patients were included in this study. The average age was 34.9, and the average Glasgow Coma Scale (GCS) score upon admission was 13.2 and was significantly lower in operated patients (10.75). Fifty-four patients were riders; 51 (94.5%!) were not wearing a helmet. Fifty percent of patients had multiple types of trauma. Six patients suffered a spinal injury. Sixteen patients required either cranial or spinal surgery. Three patients died, and 1 remained in a vegetative state. Median Glasgow Outcome Scale-Extended (GOS-E) score at follow-up was 7.1. Operated patients stayed significantly longer in the intensive care unit (ICU) and in the hospital, and their GOS-E scores at discharge and follow-up were significantly lower. Most spinal injuries underwent surgery. Patients who wore helmets had significantly higher GCS scores and a shorter stay in the ICU and hospital. The unacceptable reality of the careless use of this transportation and the unique kinematics lead to severe neurosurgical injuries, comorbidities, and even mortality. Our results reflect the risks of e-bikes in the adult population. Most of our patients were in the mid-age group, and almost none had used a helmet. The results of this study highlight the potential need for neurosurgical treatment, and the need for long-term rehabilitation and follow-up, reflecting the emotional and financial toll of these injuries. Once again, this study showed that helmets save lives and emphasized the importance of protecting our heads.

Valve Failure in Ventriculoperitoneal Shunts of Neuro-Oncologic Patients: A Historical Cohort Study.

OBJECTIVE: To investigate malfunctioning of ventriculoperitoneal shunt (VPS) valves in patients with brain tumors compared with patients with VPS for nontumoral etiologies to identify risk factors for shunt malfunction. METHODS: Medical charts of all adult patients who underwent VPS surgery for hydrocephalus between 2011 and 2016 were reviewed. Incidence and risk factors for revision surgery due to valve malfunction were identified in patients with brain tumors (group A) and patients without brain tumors (group B). RESULTS: Group A comprised 89 patients, and group B comprised 164 patients. The median follow-up time was 17 months for the entire cohort (9.4 months for group A vs. 25 months for group B, P < 0.001). VPS revision was performed in 60 patients (23.7%); 11 revisions involved valve failures necessitating valve replacement. Valve failures were significantly more common in group A (10 group A patients vs. 1 group B patient, P < 0.001). The distal or proximal shunt revision rate for reasons other than the valve was similar for both groups. Group A patients had a significantly higher cerebrospinal fluid protein level (44.5 mg/dL vs. 27.79 mg/dL, P < 0.05), and patients with valve failure had a 3-fold higher cerebrospinal fluid protein level compared with group A patients who experienced any type of shunt failure (96.3 mg/dL vs. 30.6 mg/dL, P < 0.05). CONCLUSIONS: Shunt malfunction occurred mainly in patients with brain tumors and high cerebrospinal fluid protein levels. These patients are at high risk of valve failure and should be closely observed for emergent valve revision.

5-ALA-assisted stereotactic brain tumor biopsy improve diagnostic yield.

BACKGROUND: Abnormal tissue in stereotactic brain biopsies (SBB) is traditionally identified intraoperatively via pathological frozen section (FS), a time-consuming and error-prone process. The objective of this study was to assess the efficacy of 5-aminolevulinic acid (5-ALA) administration on SBB operation time, diagnostic yield, and the associated complication rate. METHODS: We retrospectively evaluated all consecutive patients undergoing SBB with preoperative 5-ALA administration and intraoperative assessment of fluorescence (5-ALA group) between 2010 and 2017 in a single center. They were compared to all consecutive patients who underwent traditional brain biopsy with FS (control group). Demographics, clinical data, diagnostic yield of biopsies, and complication rates were documented. RESULTS: In all, 376 patients underwent SBB for suspected oncological pathology during the study period. All 34 of the 5-ALA-assisted SBB were diagnostic compared to 96.8% of the control group. The mean operative time was the same for both groups, but it was significantly shorter for the 5-ALA patients with florescent samples compared to patients with negative fluorescence (61 ±â€¯25 min vs. 136 ±â€¯54 min, P = 0.003) and compared to the control group (74 ±â€¯34 min vs. 61 ±â€¯25 min, P = 0.03). Symptomatic bleed was absent in the 5-ALA group and present in 5.4% of the controls. No adverse events were associated with preoperative 5-ALA administration. CONCLUSIONS: Preoperative administration of 5-ALA may improve the diagnostic yield of SBB and shortens operation time in cases of fluorescent pathological tissue. In addition, it may reduce the risk for associated postoperative symptomatic bleed. 5-ALA-assisted SBB is a viable alternative to traditional biopsies with FS.

From Grey Scale B-Mode to Elastosonography: Multimodal Ultrasound Imaging in Meningioma Surgery-Pictorial Essay and Literature Review.

The main goal in meningioma surgery is to achieve complete tumor removal, when possible, while improving or preserving patient neurological functions. Intraoperative imaging guidance is one fundamental tool for such achievement. In this regard, intra-operative ultrasound (ioUS) is a reliable solution to obtain real-time information during surgery and it has been applied in many different aspect of neurosurgery. In the last years, different ioUS modalities have been described: B-mode, Fusion Imaging with pre-operative acquired MRI, Doppler, contrast enhanced ultrasound (CEUS), and elastosonography. In this paper, we present our US based multimodal approach in meningioma surgery. We describe all the most relevant ioUS modalities and their intraoperative application to obtain precise and specific information regarding the lesion for a tailored approach in meningioma surgery. For each modality, we perform a review of the literature accompanied by a pictorial essay based on our routinely use of ioUS for meningioma resection.

Intraoperative Navigated Angiosonography for Skull Base Tumor Surgery.

BACKGROUND: One of the main challenges during skull base tumor surgery is identifying the relationships between the lesion and the principal intracranial vessels. To this end, neuronavigation systems based on preoperative imaging lack accuracy because of brain shift and brain deformation. Intraoperative navigated B-mode ultrasonography is useful in defining the extent of brain tumor. Doppler imaging adds information regarding flow entity in neighboring vessels. Second-generation ultrasound contrast agents improve the signal-to-noise ratio of B-mode imaging and permit the study of the vessel's course, blood flow, and perfusion characteristics of focal lesions. We report our experience using intraoperative navigated contrast-enhanced ultrasound to perform a navigated angiosonography (N-ASG) for the visualization of vessels in a series of 18 skull base tumors. METHODS: We performed N-ASG in a series of 18 skull base tumors (10 meningiomas, 3 craniopharyngiomas, 2 giant pituitary adenomas, 1 posterior fossa epidermoid, 2 dermoid cysts). N-ASG was obtained after craniotomy before resecting each lesion and during tumor removal, after intravenous injection of ultrasound contrast agent. RESULTS: In all 18 cases, major vessels and their branches were simultaneously identified (both high and low flow) using N-ASG, which allowed to visualize the whole length of each vessels. N-ASG was also useful in highlighting the lesion, compared with standard B-mode imaging, and showing its perfusion patterns. CONCLUSIONS: N-ASG can be applied to skull base tumor surgery, providing helpful information about the relationship between principal intracranial vessels and tumors. This technique could be of assistance in approaching the tumor and avoiding vascular damages.

Fusion imaging for intra-operative ultrasound-based navigation in neurosurgery.

The major shortcoming of image-guided navigation systems is the use of presurgically acquired image data, which does not account for intra-operative changes such as brain shift, tissue deformation and tissue removal occurring during the surgical procedure. Intra-operative ultrasound (iUS) is becoming widely used in neurosurgery but they lack orientation and panoramic view. In this article, we describe our procedure for US-based real-time neuro-navigation during surgery. We used fusion imaging between preoperative magnetic resonance imaging (MRI) and iUS for brain lesion removal in 67 patients so far. Surgical planning is based on preoperative MRI only. iUS images obtained during surgery are fused with the preoperative MRI. Surgery is performed under intra-operative US control. Relying on US imaging, it is possible to recalibrate navigated MRI imaging, adjusting distortion due to brain shift and tissue resection, continuously updating the two modalities. Ultrasound imaging provides excellent visualization of targets, their margins and surrounding structures. The use of navigated MRI is helpful in better understanding cerebral ultrasound images, providing orientation and panoramic view. Intraoperative US-guided neuro-navigation adjustments are very accurate and helpful in the event of brain shift. The use of this integrated system allows for a true real-time feedback during surgery.