Implementation of 3D modelling to improve understanding and conceptualisation of arteriovenous malformation (AVM) morphology for the execution of safe microsurgical excision of complex paediatric AVMs.

INTRODUCTION: Brain arteriovenous malformations (bAVMs) present complex challenges in neurosurgery, requiring precise pre-surgical planning. In this context, 3D printing technology has emerged as a promising tool to aid in understanding bAVM morphology and enhance surgical outcomes, particularly in pediatric patients. This study aims to assess the feasibility and effectiveness of using 3D AVM models in pediatric bAVM surgery. METHODOLOGY: The study was conducted at Great Ormond Street Hospital, and cases were selected sequentially between October 2021 and February 2023. Eight pediatric bAVM cases with 3D models were compared to eight cases treated before the introduction of 3D printing models. The 3D modelling fidelity and clinical outcomes were assessed and compared between the two cohorts. RESULTS: The study demonstrated excellent fidelity between 3D models and actual operative anatomy, with a median difference of only 0.31 mm. There was no statistically significant difference in angiographic cure rates or complications between the 3D model group and the non-3D model group. Surgical time showed a non-significant increase in cases involving 3D models. Furthermore, the 3D model cohort included higher-grade bAVMs, indicating increased surgical confidence. CONCLUSION: This study demonstrates the feasibility and efficacy of utilizing 3D AVM models in pediatric bAVM surgery. The high fidelity between the models and actual operative anatomy suggests that 3D modelling can enhance pre-surgical planning and intraoperative guidance without significantly increasing surgical times or complications. Further research with larger cohorts is warranted to confirm and refine the application of 3D modelling in clinical practice.

A novel technique for frame-based MR-guided laser ablation in an infant.

Hypothalamic hamartomata (HH) not only are usually associated with drug-resistant epilepsy but can also cause precocious puberty and developmental delay. Gelastic seizures are the most common type of seizures. Magnetic resonance image (MRI)-guided laser interstitial thermal therapy (LiTT) is a technique whereby a laser fibre is stereotactically implanted into a target lesion and heat is used to ablate whilst tissue temperature is monitored using MRI thermography. MRI-guided LiTT has proven to be an effective and safe method to treat HH. To use the LiTT system, highly accurate stereotactic fibre implantation is required. This can be achieved by the use of frame-based or frameless neuronavigation techniques. However, these techniques generally involve rigid head immobilisation using cranial pin fixation. Patients need sufficient skull thickness to safely secure the pins and sufficient skull rigidity to prevent deformation. Hence, most of the clinical reports on the use of LiTT for children describe patients aged 2 years or older. We report a novel and practical technique of using a paste cast helmet to securely place a stereotactic frame in a 5-month-old infant with HH and drug-resistant epilepsy that allowed the successful application of MRI-guided LiTT.

Giant Supratentorial Brain Tumors in Children: Functional Outcome and Progression-Free Survival Analysis.

INTRODUCTION: This study aimed to identify factors affecting progression-free survival (PFS) in pediatric patients with giant supratentorial brain tumors (GSBTs) treated with surgical excision. The secondary aim was to analyze how these same factors affected the functional outcome in the long term. METHODS: We performed a retrospective, analytical, single-center cohort study. We included all pediatric patients with GSBT between January 2014 and June 2018. Patients were followed for a minimum of 24 months for the PFS and overall survival (OS) analysis. Functional status score (FSS) was used to assess the functional outcome. RESULTS: We included 27 patients with GSBT, the median age was six (range 2-12), and eleven patients had a grade IV tumor. The 24-month PFS and OS were 51.85% and 74.04%, respectively. A PFS-ending event or treatment failure occurred in 13 patients. We found that patients with postoperative FFS >16 have a worse PFS than patients with a postoperative FSS <15 (HR 4.51; p = 0.03). Patients with more than three surgeries had worse PFS than patients with one or two procedures (HR 11.39; p = 0.004). High-grade tumors were associated with worse PFS than low-grade tumors (HR 1.55; p = 0.04). Finally, patients with CNS infections had worse PFS than patients without that complication (HR 2.70; p = 0.04). CONCLUSIONS: GSBTs in pediatric patients are complex lesions that require multidisciplinary management. Surgical management and quality of life should be considered when choosing the best treatment. Factors influencing long-term PFS were high-grade histopathology, the need for three or more surgeries, postoperative FSS >16, and CNS infections.

A rare case of atlantoaxial rotatory fixation after posterior calvarial vault expansion surgery in a Crouzon patient.

INTRODUCTION: Atlantoaxial rotatory fixation (AARF) is a rare condition that occurs most commonly in children. The torticollis caused by AARF usually presents as abnormal posturing of the head and neck, with rotation of the chin to the opposite side. AARF in children could occur due to congenital bony malformation, minor trauma, upper respiratory tract infections (Grisel's syndrome), postoperatively after head and neck (ENT) surgery, and unknown reasons. AARF in the postoperative patient is a rare and poorly understood entity. METHODS: The authors present a case report of a 2-year-old boy with Crouzon Syndrome undergoing posterior calvarial vault expansion (PVE) surgery that developed AARF as a complication. RESULTS: The authors believe that cranial vault surgery should be considered a potential risk procedure for AARF, especially if it is done in susceptible populations (syndromic craniosynostosis patients) with other underlying sequelae (tonsillar ectopia or syringomyelia). During surgery, careful attention should be paid to maintaining a neutral alignment of the patient's cervical spine as rotatory movements under anaesthesia and muscle relaxation may be contributory factors. CONCLUSION: AARF should be suspected and investigated in children with painful torticollis after craniofacial surgery.

The sellar barrier on preoperative imaging predicts intraoperative cerebrospinal fluid leak: a prospective multicenter cohort study.

BACKGROUND: The type of sellar barrier observed between a pituitary tumor and cerebrospinal fluid (CSF) on preoperative magnetic resonance imaging (MRI) may predict intraoperative CSF leak during endonasal pituitary surgery. This is the first multicentric prospective cohort trial to study the sellar barrier concept and CSF leak rate during endoscopic pituitary surgery. METHODS: This multi-center, international study enrolled patients operated for pituitary adenomas via fully endoscopic endonasal surgery over a period of 4 months. The independent variable was the subtype of sellar barrier observed on preoperative MRI (strong, mixed or weak); the dependent variable was the presence of an intraoperative CSF leak. The primary goal was to determine the association between a particular type of sellar barrier and the risk of intraoperative CSF leak. Appropriate statistical methods were then applied for data analysis. RESULTS: Over the study period, 310 patients underwent endoscopic endonasal surgery for pituitary tumor. Preoperative imaging revealed a weak sellar barrier in 73 (23.55%), a mixed sellar barrier in 75 (24.19%), and a strong sellar barrier in 162 (52.26%) patients. The overall rate of intraoperative CSF leak among all patients was 69 (22.26%). A strong sellar-type barrier was associated with significantly reduced rate of intraoperative CSF leak (RR = 0.08; 95% CI 0.03-0.19; p < 0.0001), while a weak sellar barrier associated with higher rates of CSF leak (RR = 8.54; 95% CI 5.4-13.5; p < 0.0001). CONCLUSIONS: The preoperative MRI of pituitary patients can suggest intraoperative CSF leak rates, utilizing the concept of the sellar barrier. Patients with a weak sellar barrier carry a higher risk for an intraoperative CSF leak, whereas a strong sellar barrier on MRI seems to mitigate intraoperative CSF leak. We propose that preoperatively assessment of the sellar barrier can prepare surgeons for intraoperative CSF leak repair.

Giant dural arteriovenous fistula in a pediatric patient: positive outcome following surgical treatment.

PURPOSE: Our purpose is to present an atypical case of a 4-month-old patient with a giant dural arteriovenous fistula (DAVF). METHODS: Presentation of a case report and review of the literature. RESULTS: The DAVF arterial supply was through the middle meningeal artery bilaterally and the anterior and middle cerebral arteries on the right hemisphere. The venous drainage was through the posterior two-thirds of the superior sagittal sinus. The endovascular team performed an embolization to reduce the flow of the lesion, and finally, the surgical team completed the excision of the residual venous sac, without causing any significant neurological deficit. We used a double surgical approach done with two surgical teams in order to optimize the hemostasis control and reduce morbidity and mortality. CONCLUSION: Midline DAVF usually has devastating consequences in children. Endovascular treatment is the first choice since it has lower mortality. Nevertheless, it requires multiple interventions, and the cure of the disease may not be achieved. We believe that joint endovascular and surgical treatment, supported by a reliable multidisciplinary medical team, is a good option for this type of lesions.

Baclofen pump with pre-brainstem catheter tip placement: technical note and case series.

PURPOSE: This study aims to describe a new baclofen pump implantation technique with pre-brainstem catheter placement and to demonstrate the benefits that this procedure has in treating spasticity and dystonia. METHODS: We described a new technique to place a baclofen pump catheter anterior to the brainstem. To illustrate the technique, we presented five patients with both spasticity and dystonia in whom conventional treatment was not effective. They each received a baclofen pump with a pre-brainstem catheter. We evaluated the results using the Ashworth scale for spasticity, the Barry-Albright scale for dystonia, and the PedsQL for quality of life assessment. Each patient was evaluated before a surgery and after 6 months of follow-up. RESULTS: There were statistically significant differences in all the physical examination evaluated areas using the Barry-Albright and modified Ashworth scales between the preoperative and the postoperative period. The same applies to the results of the PedsQL quality of life scale. CONCLUSION: We presented an innovative baclofen pump implantation technique with pre-brainstem catheter placement that could be a therapeutic alternative in patients with dystonia and spastic quadriparesis for whom conventional therapy is not effective.

Risk factors for surgical site infection in pediatric posterior fossa tumors.

PURPOSE: Posterior fossa tumors are the most frequent pediatric solid tumor. Its main treatment is a surgical resection. Being a frequent procedure does not mean that it is exempt from complications, such as surgical site infections (SSI). The main objective of this paper is to study the risk factors associated with SSI following a resection of posterior fossa tumors in a purely pediatric population. METHODS: A retrospective case-control study including all posterior fossa tumor surgeries performed at our hospital between January 2014 and December 2019 was conducted. All patients with a diagnosis of a postoperative SSI have been included as cases, and those who had surgery and no infectious complications have been considered as controls. RESULTS: When analyzing risk factors, we have found that patients with ventriculoperitoneal shunt (VPS) (p = 0.03) or external ventricular drainage (EVD) (p = 0.005) placement had a greater chance of presenting a postoperative surgical site infection. Prolonged operative time (p < 0.001) and cerebrospinal fluid (CSF) leak through the wound (p = 0.002) also caused an increase in the risk of SSI in the postoperative period. A higher hemoglobin value (p = 0.002) would seem to be a preventive factor. CONCLUSIONS: Some strategies that could help to reduce the risk of infections are managing hydrocephalus preferably with endoscopic third ventriculostomy, minimizing the needed operative time to perform the procedure, obtaining an adequate serum hemoglobin level, and avoiding CSF leak through the wound.

Abdominal complications in patients with a ventriculoperitoneal shunt: proposal for management recommendations from a single pediatric tertiary center.

PURPOSE: The aim of this study was to describe our experience in the management of patients with ventriculoperitoneal shunt-related complications (abdominal pseudocyst, bowel-related complications, and ascites) and to propose treatment recommendations. MATERIAL AND METHODS: A retrospective descriptive study was conducted in patients with ventriculoperitoneal shunt-related abdominal complications seen between 2009 and 2019 at a tertiary-care pediatric center. Patients were classified according to their diagnosis into the following: group A (abdominal pseudocyst), group B (bowel-related complications), and group C (ascites). The following variables were studied in all three groups: age, sex, etiology of hydrocephalus, history of pyogenic ventriculitis, history of abdominal surgery, clinical presentation, presence of ventricular enlargement on computed tomography scan, abdominal ultrasonography, shunt series X-ray, cerebrospinal fluid cultures, urgent as well as elective surgical interventions, antibiotic treatment, length of hospital stay, follow-up, and outcome. RESULTS: Overall, 48 patients were analyzed: group A, n=29; group B, n=15; and group C, n=4. In all cases, surgical decision-making was based on symptom severity at the time of diagnosis, presence of ventricular enlargement on computed tomography scan, and cerebrospinal fluid culture results. In patients with positive cultures, the shunt system was removed, and an external ventricular drain was placed. In oligosymptomatic patients, cerebrospinal fluid culture results were awaited to define long-term treatment and in patients with ventricular enlargement or clinically difficult-to-treat symptoms, the distal catheter was exteriorized at the thoracic level. CONCLUSION: In patients with shunt-related abdominal complications, surgical management depends on symptom severity and/or whether infection is present at the time of diagnosis.

Ruptured dermoid cyst in the Meckel's cave presenting with trigeminal neuralgia in a pediatric patient: a case report.

Intracranial dermoid cysts are benign congenital slow growing masses. They account for less than 1% of all primary intracranial lesions. They can be asymptomatic and appear incidentally on brain images. However, there are some dermoid cysts that, depending on the location, can cause a variety of symptoms, especially if they compress vital structures. Rupture of intracranial dermoid cysts is relatively uncommon; the incidence is 0.18%. Dermoid cyst in children appears in the posterior fossa, while in adults is more common to find them in the sellar, temporal, and frontobasal region. The Meckel's cave is not a frequent location for these lesions and there are only a few cases in the adult population reported in the literature. We presented a 12-year-old patient with a dermoid cyst in the Meckel's cave who first presented with symptoms of a ruptured cyst but eventually evolved with a trigeminal neuralgia. We decided to do a transzygomatic approach and a middle fossa pealing to locate and excise the lesion. After surgery, the patient resolved the symptoms. Surgery is recommended in symptomatic lesions although surgical decision-making should consider the region where the cyst is located to achieve a safe, maximal resection without adding any further damage.

Long-tunneled versus short-tunneled external ventricular drain: a quasi-experimental study in a cohort of pediatric patients.

OBJECTIVE: The primary aim of this study was to compare external ventricular drain (EVD)-related infection rates and mechanical complications between long-tunneled EVDs (LTEVDs) with an interposed valve and short-tunneled EVDs (STEVDs) in a cohort of pediatric patients. The second objective was to compare hospital resources used for LTEVDs versus STEVDs in the same cohort of patients and the same study period. METHODS: The study consisted of a quasi-experimental investigation comparing a prospective group of patients who received LTEVDs with a retrospective (historic) cohort of patients treated with STEVDs. The prospective nonrandomized quasi-experimental protocol of the LTEVD cohort included patients who needed an EVD for more than 3 days. Data were recorded prospectively as the patients were added to the study, until reaching the sample size established by the protocol. The comparison group of the STEVD cohort was retrospectively collected from patients' records. Patients were included consecutively, from newest to oldest, starting with the last STEVD inserted at the authors' hospital until reaching the sample size established in the protocol. The inclusion and exclusion criteria for both groups were the same. RESULTS: One hundred thirty-four patients were included in this quasi-experimental study; there were 67 in each group. LTEVDs reduced the odds of having an EVD-related infection by 92% (OR 0.08, 95% CI 0.01-0.39; p = 0.002). Compared to STEVDs, the LTEVDs reduced by 69% the odds of having a CSF leak (OR 0.31, 95% CI 0.10-0.91; p = 0.03). Neither CSF blockage (OR 0.12, 95% CI 0.01-1.08; p = 0.06) nor displacement (OR 0.73, 95% CI 0.15-3.43; p = 0.69) showed a statistically significant difference between groups. More resources were allocated to STEVDs than to LTEVDs in most areas considered in this study. CONCLUSIONS: Compared to STEVDs, LTEVDs are a cost-effective and safe method to reduce EVD-related infection rates and other complications in pediatric patients. The authors believe that reducing the infection rate and complications and giving the patient more independence outweighs the additional costs that this new technique may entail.

Parental sensitivity and specificity to recognize shunt malfunction in their child: a single-center prospective study.

OBJECTIVE: The objective of this study was to estimate the diagnostic performance (sensitivity, specificity, positive predictive value, and negative predictive value) for recognizing ventriculoperitoneal shunt (VPS) failure in the parents of patients 0-18 years of age who attended the hospital's emergency room (ER). The second objective was to identify the factors associated with the parents' ability to recognize the shunt blockage (true positives). METHODS: A prospective cohort study was conducted between 2021 and 2022 including all patients 0-18 years of age who had a VPS and attended the hospital's ER with symptoms that could correspond to VPS blockage. Parents were interviewed on admission and patients were assessed over time to discover potential VPS malfunction by surgery or follow-up. Consent was obtained from all participants. RESULTS: Ninety-one patients were surveyed, and 59.3% showed evidence of a confirmed VPS blockage. Parental sensitivity was 66.7%, with a specificity of 21.6%. An association was found between parents who could correctly identify their child's shunt block and the number of symptoms of shunt failure that the parent could name (OR 2.4, p < 0.05) as well as parents who reported vomiting and headache as symptoms of shunt malfunction (OR 6, p < 0.05). Parents who knew the first and last name of their primary neurosurgeon (OR 3.5, p < 0.05) also had better diagnostic sensitivity. CONCLUSIONS: Parents who are more knowledgeable of their child's disease, as well as parents who have good communication with their neurosurgeon, were found to have better diagnostic sensitivity.

Endoscopic third ventriculostomy for the management of children with cerebrospinal fluid disorders, ventriculomegaly, and associated Chiari I malformation.

OBJECTIVES: Our objective was to review the outcomes of children with CIM and associated cerebrospinal fluid (CSF) disorders and ventriculomegaly undergoing endoscopic third ventriculostomy (ETV) as a primary intervention. MATERIALS AND METHODS: A retrospective, single-center, observational cohort study was conducted of consecutive children with CIM with associated CSF disorders and ventriculomegaly treated first by ETV between January 2014 and December 2020. RESULTS: Raised intracranial pressure symptoms were the most frequent in ten patients, followed by posterior fossa and syrinx symptoms in three cases. One patient had a later stoma closure and required a shunt insertion. The success rate of the ETV in the cohort was 92% (11/12). There was no surgical mortality in our series. No other complications were reported. The median herniation of the tonsils was not statistically different in the pre vs. post-operative MRI (1.14 vs. 0.94, p=0.1). However, the median Evan's index (0.4 vs. 0.36, p<0.01) and the median diameter of the third ventricle (1.35 vs. 0.76, p<0.01) were statistically different between the two measurements. The preoperative length of the syrinx did not change significantly compared with the postoperative (5 vs. 1; p=0.052); nevertheless, the median transverse diameter of the syrinx did improve significantly after the surgery (0.75 vs. 0.32, p=0.03). CONCLUSIONS: Our study supports ETV's safety and effectiveness for managing children with CSF disorders, ventriculomegaly, and associated CIM.

Intradural extramedullary tumors. Retrospective cohort study assessing prognostic factors for functional outcome in adult patients.

OBJECTIVE: The purpose of this study is to analyze a series of patients with intradural extramedullary tumors (IDEM) and assess factors that may modify or determine the final long term outcome and management. MATERIALS AND METHODS: Single Center, retrospective study of a series of surgical patients with IDEM lesions from our Institution operated between 2010 and 2021. Patients with less than 6 months of follow up were excluded. Several preoperative demographics, clinical, imaging and surgical features, as well as histopathology, recurrence and adjuvancy were assessed. Patients' final clinical outcome was categorized using the McCormick scale. RESULTS: A total of 203 patients with a mean follow-up of 30.50 months (range 6-130) were included. 57.64% of the analyzed population was female and the mean age was 50.51 years. The most frequent location of the tumors was dorsal (34.98%) followed by the lumbar region (32.02%). Total resection was achieved in 84.24% of cases, and the most frequent histopathology was Schwannoma (36.45%), followed by Meningioma (30.05%). Pain was the most usual initial symptom (63.05%). In our analysis, functional outcome after surgery was associated with statistical significance with preoperative McCormick grade, tumor type, EOR and postoperative complications such as hematoma and sphincter involvement. CONCLUSION: The management of these lesions depends on many factors. It is worthy of mention that clinical presentation, EOR, histopathology and postoperative complications have shown significant prognostic value for the final outcome. Early treatment with the intention of achieving GTR when possible, using carefully tailored approaches, should be considered before the onset of significant symptoms.

Clinical Applicability of the Sellar Barrier Concept in Patients with Pituitary Apoplexy: Is It Possible?

There is evidence of association between sellar barrier thickness and intraoperative cerebrospinal fluid (CSF) leakage, impacting the postoperative prognosis of the patients. The aim of this study is to analyze the clinical applicability of the sellar barrier concept in a series of operated patients with pituitary apoplexy (PA). A retrospective study was conducted including 47 patients diagnosed with PA who underwent surgical treatment through a transsphenoidal approach. Brain magnetic resonance imaging (MRI) of the patients were evaluated and classified utilizing the following criteria: strong barrier (greater than 1 mm), weak barrier (less than 1 mm), and mixed barrier (less than 1 mm in one area and greater than 1 mm in another). The association between sellar barrier types and CSF leakage was analyzed, both pre- and intraoperatively. The preoperative MRI classification identified 10 (21.28%) patients presenting a weak sellar barrier, 20 patients (42.55%) with a mixed sellar barrier, and 17 patients (36.17%) exhibiting a strong sellar barrier. Preoperative weak and strong sellar barrier subtypes were associated with weak (p ≤ 0.001) and strong (p = 0.009) intraoperative sellar barriers, respectively. Strong intraoperative sellar barrier subtypes reduced the odds of CSF leakage by 86% (p = 0.01). A correlation between preoperative imaging and intraoperative findings in the setting of pituitary apoplexy has been observed.

Cranial dermal sinuses in pediatrics: Presentation, diagnosis, complications, and management. Experience at a tertiary care children's hospital. / Senos dérmicos craneales en pediatría: presentación, diagnóstico, complicaciones y tratamiento. Experiencia de un hospital pediátrico de nivel III.

INTRODUCTION: A cranial dermal sinus is a tubular tract resulting from the incomplete separation of the epithelial ectoderm from the neuroectoderm which may lead to infectious complications. There have been isolated reports of this condition. OBJECTIVE: A cranial dermal sinus is a tubular tract resulting from the incomplete separation of the epithelial ectoderm from the neuroectoderm which may lead to infectious complications. There have been isolated reports of this condition. POPULATION AND METHODS: Observational, descriptive study of a series of pediatric patients with cranial dermal sinus treated at a tertiary care children's hospital between 2014 and 2019. RESULTS: Observational, descriptive study of a series of pediatric patients with cranial dermal sinus treated at a tertiary care children's hospital between 2014 and 2019. CONCLUSIONS: In this series, dermal sinuses presented as specific lesions on the scalp. The most common site was the occipital midline, and more than 50% of these extended through the bone. The treatment of choice was complete resection of dermal sinus and associated lesions. An emergency surgery was performed when the dermal sinus was symptomatic or associated with intracranial lesions.

Introducción. El seno dérmico cefálico es un tracto tubular formado por una separación incompleta entre el ectodermo neural y el ectodermo epitelial; puede tener complicaciones infecciosas. Existen reportes aislados de esta patología. OBJETIVO: describir una serie de pacientes con seno dérmico craneal, las formas de presentación, el diagnóstico, el tratamiento y las complicaciones. Población y métodos. Estudio observacional descriptivo de una serie de pacientes pediátricos con seno dérmico cefálico atendidos en un hospital pediátrico de nivel III entre 2014 y 2019. RESULTADOS: se incluyeron 18 pacientes. La clínica de presentación fue, en 12 casos, una lesión puntual en el cuero cabelludo, hipertensión endocraneana en 4 casos, ataxia en 1 caso y lesión puntual con fístula en 1 caso. La mitad presentó síntomas de infección. La localización fue en la línea media sobre el hueso occipital en 13 casos, en la línea media sobre el hueso frontal en 3 casos y en la línea media interparietal en 2 casos. En 5 casos se encontró asociada una imagen extracraneana y, en 11 casos, una complicación intracraneana. Ningún paciente presentó recidiva de la lesión y en todos se realizó un solo procedimiento quirúrgico. CONCLUSIONES: Los senos dérmicos en esta serie se presentaron como lesiones puntuales en cuero cabelludo. La localización más frecuente fue a nivel occipital sobre línea media y, en más de la mitad, atravesaba el hueso. El tratamiento de elección fue la exéresis completa del seno dérmico y las lesiones asociadas. Ante la presencia de senos dérmicos sintomáticos o asociados a lesiones intracraneanas, la cirugía se realizó de urgencia.

Classification and Management of Pontecerebellar-Petrosal Bridging Veins.

OBJECTIVES: The risks and benefits of coagulating intradural venous elements during a retrosigmoid approach for trigeminal neurovascular decompression has not been accurately established. The objectives of this study were to identify the veins that drain into the superior petrosal sinus, classify them in relation to the suprameatal tubercle, and determine the implication of their coagulation. METHODS: A retrospective study of 3-dimensional surgical videos of retrosigmoid approaches for trigeminal neurovascular decompression from the Laboratory of Neurosurgical Innovations of Tucumán (LINT) digital archive was carried out. The veins encountered were classified into 3 groups: retromeatal, meatal and premeatal. The neurosurgical postoperative complication scale proposed by Landriel et al. was utilized to assess complications from venous coagulation. A grade 0 was added for patients without complications. The STATA 14 program was utilized for statistical analysis. RESULTS: The pontocerebellar-petrosal veins of 28 patients who underwent trigeminal decompressive surgery were analyzed. In 7 cases these were found in the retromeatal region; 100% were sacrificed. Eleven cases revealed veins within the meatal region; 90.91% were coagulated. Veins in the premeatal region were found in 14 cases; 57.14% were sacrificed. In the postoperative follow-up, 27 patients were grade 0 and 1 patient developed postoperative meningitis (grade Ib complication). No patient suffered vascular complications. CONCLUSIONS: The venous elements identified in trigeminal neurovascular decompressive surgery are variable. We propose classifying them into retromeatal, meatal, and premeatal groups. Retromeatal and meatal veins can be safely sacrificed for appropriate visualization of the neurovascular conflict. The premeatal venous elements should be coagulated only in justified cases.

Use of Neuroanatomic Knowledge and Neuronavigation System for a Safe Anterior Petrosectomy.

INTRODUCTION: The petroclival region is among the most challenging anatomical areas to deal with in skull base surgery. Drilling of the anterior part of the petrous bone during the anterior transpetrosal approach involves the risk of injury of the cochlea, superior semicircular canal, internal carotid artery, and internal auditory canal. A thorough understanding of the microneurosurgical anatomy of this region is mandatory to execute the transpetrosal approaches, decreasing the risk of complications. The aim of this study is to describe the anatomical structures of the petroclival region, highlighting the importance of neuronavigation for safe performance of the anterior transpetrosal approach. METHODS: Three adult cadaveric human heads were formalin-fixed and injected with colored silicone. They underwent an axial 1 mm slab CT scan, which was used for neuronavigation during the surgical approaches. The anterior petrosectomy was performed with the aid of neuronavigation during the drilling of the petrous bone. The surgical management of a patient harboring a petroclival meningioma, operated on using an anterior transpetrosal approach, was reported as an illustrative case. RESULTS: The anterior petrosectomy was completed accurately with wide exposure of the surgical target without injuring the cochlea and other structures in all three cadaveric specimens. In the surgical case, no approach-related complications occurred, and a gross total resection of the tumor was achieved. CONCLUSIONS: Deep knowledge of the location and relationships of the vital elements located within the temporal bone, along with the use of neuronavigation, are the key aspects to perform the anterior transpetrosal approach safely, reducing the risk of complications.

Orbitomeningeal Band in Transcavernous Dissection and Anterior Clinoidectomy: 3-Dimensional Operative Video.

The orbitomeningeal or meningo-orbital band (MOB) has been described as the most superficial dural band responsible for tethering the frontotemporal basal dura to the periorbita.1,2 The MBO usually interferes with the surgical approach to the most profound areas of the anterior and middle skull base. It is known that there are no cranial nerves on the lateral surface of the superior orbital fissure; therefore, the neurosurgeon can cut the MOB without causing any neurological deficit and, at the same time, achieving fully exposure of the anterior clinoid process1-4 and/or the lateral wall of the cavernous sinus.5 The purpose of this video is to describe the microsurgical anatomy of the MOB and illustrate the technique for its detachment, accompanied by 2 illustrative cases. To achieve this, we use 3-dimensional recordings of 2 cadaveric specimens' dissections performed by the senior author. Case 1: 58-yr-old female with left blindness. Magnetic resonance imaging (MRI) shows an anterior and middle skull base lesion with orbital compression. Case 2: 32-yr-old male presenting with headache and trigeminal neuralgia. The MRI revealed an hourglass-shaped lesion in the posterior and middle fossa. Both patients signed an informed consent and agree with the use of their images for research purposes. We used a step-by-step approach for an adequate and secure dissection of the MOB highlighting the anatomic structures involved in the process. This approach allows safe and adequate access to the deeper structures of the anterior and middle skull base.

New Simulator for Neuroendoscopy: A Realistic and Attainable Model.

OBJECTIVE: To present an attainable and realistic model for neuroendoscopic simulation which replicates exercises of tissue biopsy and coagulation and membrane fenestration. METHODS: We presented a stepwise method to create a neuroendoscopic simulation model using bovine brain and membrane units made by a soda cup covered by an amniotic membrane inside an expanded polystyrene spherical container. We used face validation for preliminary evaluation. We also rated the students before and after training with the NEVAT global rating scale (GRS) and recorded the time required to complete all 3 procedures (third ventriculostomy, tissue biopsy, and coagulation). The total cost of the model was $5. RESULTS: The experts consider this new model as capable of reproducing real surgical situations with great similarity to the human brain. We tested the model in 20 trainees. The median GRS score before the training was 9 (range, 7-12). After repeated training and performance feedback, the final median GRS score was 41 (range, 37.5-45; P < 0.0001). The time needed to finish the exercises before training was 33 minutes (range, 30.5-42.5 minutes), and after using the model the final median time was 20 minutes (range, 17.5-22 minutes; P < 0.0001). CONCLUSIONS: Simulators for neuroendoscopy described so far are reliable, but they entail a high cost. Models with live animals, although of lower cost, are questioned from an ethical point of view. In the current work, we describe a high fidelity ventricular neuroendoscopic simulator model that, because of its low cost, can be replicated in any training center that has a neuroendoscope.