Utility of intracranial pressure monitoring as a diagnostic tool in pediatric ventriculomegaly.

OBJECTIVE: Intracranial pressure (ICP) monitoring is commonly utilized for identifying pathologic ICP in cases of traumatic brain injury; however, its utility in hydrocephalic children has not been elucidated. Although patients with typical (pressure-active) hydrocephalus present with clear signs and/or symptoms and the need for cerebrospinal fluid (CSF) diversion is often clear, others may have arrested or pressure-compensated hydrocephalus with pathologic ICP elevation masked by ambiguous signs or are completely asymptomatic. Without treatment these pathologic ICP elevations may affect neurologic development or crescendo over time leading to neurological decline. The purpose of this study is to investigate the utility of ICP monitoring as a diagnostic tool in this relatively common patient population and identify ventriculomegaly patients with and without pathologic ICP, thus improving accuracy of identifying those with and without surgical needs. METHODS: 36 patients (≤ 17 years old) underwent 41 inpatient ICP recording sessions between 2016 and 2022 and were retrospectively reviewed. This included patients with a history of severe, nonprogressive ventriculomegaly and normal fundoscopic examinations lacking traditional signs and symptoms concerning for elevated ICP. Nighttime pathological plateau waves were defined as sustained elevations of ICP ≥ 2x baseline for a duration of ≥ 5 minutes. RESULTS: The mean age of patients was 5.5 years old (range 0-17 years old). 46.3% of patients had prior endoscopic third ventriculostomy (ETV), 14.6% had prior ventriculoperitoneal shunt (VPS), and 39% were without prior surgical intervention. Roughly half (51.2%) of patients had congenital ventriculomegaly while other patients had ventriculomegaly due to other pathologies such as germinal matrix hemorrhage/intraventricular hemorrhage (GMH/IVH) (29.3%), stroke (4.9%), cerebral infections/meningitis (2.4%), or unknown etiology (12.2%). The average procedure time was 19.1 ± 10.5 minutes, and mean length of stay was 2.8 ± 0.7 days. Pathologic ICP was demonstrated in 12 cases (29.3%), 4 (33.3%) of which were asymptomatic. Pathologic ICP was found in 7 of 19 (36.8%) in the prior ETV group, 1 of 6 (16.7%) in prior shunt group, and 4 of 16 (25%) in the non-surgical group (p = 0.649). Among those with pathologic ICP, 6 (50%) cases received an ETV, 5 (41.7%) cases underwent VPS placement, and 1 (8.3%) case underwent a VPS revision. There were no infectious complications or cases of hemorrhage. 4 patients required repositioning of the ICP monitor due to dislodgement. CONCLUSION: Inpatient ICP monitoring is a safe and effective diagnostic tool for evaluating the presence of pathologic ICP in severe, persistent non-progressive ventriculomegaly. The use of ICP monitoring may aid in identifying patients with pressure-compensated hydrocephalus who demonstrate pathologic ICP where surgical intervention may be warranted, while preventing unnecessary CSF diversion in those without pathology.

Infantile traumatic pericallosal aneurysm: illustrative case.

BACKGROUND: Traumatic aneurysms are a rare sequela of nonaccidental head trauma in infants. The rate of nonaccidental trauma (NAT) in the pediatric population is increasing; therefore, traumatic aneurysms are an important consideration in the evaluation of pediatric patients with abusive head trauma. OBSERVATIONS: A 24-day-old infant with no significant past medical or birth history presented with twitching and poor oral intake for 1 day. The patient was found to have bilateral subdural hematomas, multifocal contusions, and traumatic subarachnoid hemorrhage. NAT work-up was remarkable for a period of repeated and prolonged abuse. Magnetic resonance angiography revealed a right pericallosal traumatic aneurysm that was treated by means of coil and Onyx embolization. LESSONS: Traumatic intracranial aneurysms are a rare but serious sequela of pediatric abusive trauma. Traumatic intracranial aneurysms should be considered in the setting of intracranial pathology associated with high-energy trauma. Despite new methods for the management of traumatic aneurysms, this pathology remains challenging to identify and treat, and the prognosis remains poor because of the diffuse injury often involved in these patients.

Exoscope Efficacy and Feasibility in Pediatric Spinal Neurosurgery: A Single-Institution Cohort Case Series.

BACKGROUND: The exoscope has emerged as an efficacious microscope in adult spinal neurosurgery providing improved operative field visibility and surgeon ergonomics. However, outcome data and feasibility are underrepresented in the pediatric literature. We present the largest case series aimed at assessing operative and clinical outcomes in pediatric patients undergoing various exoscope-assisted spinal surgeries. METHODS: A retrospective review was conducted on all consecutive pediatric (age <18 years) spinal surgeries performed with the use of an exoscope by 3 senior surgeons at a single institution from 2020-2023. Demographics and clinical and operative outcomes were reviewed and analyzed. RESULTS: Ninety-six exoscope-assisted pediatric spine surgeries were performed on 89 unique patients, 41 (42.7%) of which were male. The mean age at surgery was 12 (±5.3) years. Spinal cord detethering (55.8%) was the most common procedure performed. The overall mean operative time for all procedures was 155 (±86) minutes, and the mean estimated blood loss was 18 (±41) mL. The mean length of stay was 5.4 (±6.5) days. There were 14 (14.6%) patients with complications in this cohort. At final follow-up, 64 (83.1%) of symptomatic patients reported neurologic symptom improvement. CONCLUSIONS: Using the exoscope in a variety of pediatric spinal surgeries resulted in an acceptable average operative time, estimated blood loss, length of stay, and rate of neurologic symptom improvement. The exoscope appears to be an efficacious option for pediatric neurosurgical spinal procedures.

Congress of Neurological Surgeons Systematic Review and Evidence-Based Guidelines for Patients With Chiari Malformation: Surgical Interventions.

BACKGROUND: Chiari malformation type I (CIM) diagnoses have increased in recent years. Controversy regarding the best operative management prompted a review of the literature to offer guidance on surgical interventions. OBJECTIVE: To assess the literature to determine (1) whether posterior fossa decompression or posterior fossa decompression with duraplasty is more effective in preoperative symptom resolution; (2) whether there is benefit from cerebellar tonsillar resection/reduction; (3) the role of intraoperative neuromonitoring; (4) in patients with a syrinx, how long should a syrinx be observed for improvement before additional surgery is performed; and 5) what is the optimal duration of follow-up care after preoperative symptom resolution. METHODS: A systematic review was performed using the National Library of Medicine/PubMed and Embase databases for studies on CIM in children and adults. The most appropriate surgical interventions, the use of neuromonitoring, and clinical improvement during follow-up were reviewed for studies published between 1946 and January 23, 2021. RESULTS: A total of 80 studies met inclusion criteria. Posterior fossa decompression with or without duraplasty or cerebellar tonsil reduction all appeared to show some benefit for symptom relief and syrinx reduction. There was insufficient evidence to determine whether duraplasty or cerebellar tonsil reduction was needed for specific patient groups. There was no strong correlation between symptom relief and syringomyelia resolution. Many surgeons follow patients for 6-12 months before considering reoperation for persistent syringomyelia. No benefit or harm was seen with the use of neuromonitoring. CONCLUSION: This evidence-based clinical guidelines for the treatment of CIM provide 1 Class II and 4 Class III recommendations. In patients with CIM with or without syringomyelia, treatment options include bone decompression with or without duraplasty or cerebellar tonsil reduction. Improved syrinx resolution may potentially be seen with dural patch grafting. Symptom resolution and syrinx resolution did not correlate directly. Reoperation for a persistent syrinx was potentially beneficial if the syrinx had not improved 6 to 12 months after the initial operation. The full guidelines can be seen online at https://www.cns.org/guidelines/browse-guidelines-detail/3-surgical-interventions .

Congress of Neurological Surgeons Systematic Review and Evidence-Based Guidelines for Patients With Chiari Malformation: Diagnosis.

BACKGROUND: Chiari I malformation (CIM) is characterized by descent of the cerebellar tonsils through the foramen magnum, potentially causing symptoms from compression or obstruction of the flow of cerebrospinal fluid. Diagnosis and treatment of CIM is varied, and guidelines produced through systematic review may be helpful for clinicians. OBJECTIVE: To perform a systematic review of the medical literature to answer specific questions on the diagnosis and treatment of CIM. METHODS: PubMed and Embase were queried between 1946 and January 23, 2021, using the search strategies provided in Appendix I of the full guidelines. RESULTS: The literature search yielded 567 abstracts, of which 151 were selected for full-text review, 109 were then rejected for not meeting the inclusion criteria or for being off-topic, and 42 were included in this systematic review. CONCLUSION: Three Grade C recommendations were made based on Level III evidence. The full guidelines can be seen online at https://www.cns.org/guidelines/browse-guidelines-detail/1-imaging .

Congress of Neurological Surgeons Systematic Review and Evidence-Based Guidelines for Patients With Chiari Malformation: Symptoms.

BACKGROUND: Chiari I malformation (CIM) is characterized by descent of the cerebellar tonsils through the foramen magnum, potentially causing symptoms from compression or obstruction of the flow of cerebrospinal fluid. Diagnosis and treatment of CIM is varied, and guidelines produced through systematic review may be helpful for clinicians. OBJECTIVE: To perform a systematic review of the medical literature to answer specific questions on the diagnosis and treatment of CIM. METHODS: PubMed and Embase were queried between 1946 and January 23, 2021, using the search strategies provided in Appendix I of the full guidelines. RESULTS: The literature search yielded 430 abstracts, of which 79 were selected for full-text review, 44 were then rejected for not meeting the inclusion criteria or for being off-topic, and 35 were included in this systematic review. CONCLUSION: Four Grade C recommendations were made based on Class III evidence, and 1 question had insufficient evidence. The full guidelines can be seen online at https://www.cns.org/guidelines/browse-guidelines-detail/2-symptoms .

A Multicenter Study Investigating the Surgeon Experience with a Robotic-Assisted Exoscope as Part of the Neurosurgical Armamentarium.

BACKGROUND: Improvement of visualization tools in neurosurgery such as the exoscope has raised the question of how this technology compares to the conventional microscope for surgeon ergonomics, discomfort, and patient outcomes. Exoscopes have the advantage of greater optical zoom, resolution, and illumination at a lower light intensity. Heads-up display for both the primary surgeon and other assistants permits neutral positioning of the surgeons while placing the camera in more angled positions. In a survey sample, this study assesses the surgeon experience utilizing 3D exoscope in general neurosurgery cases. METHODS: Data weere recorded by 8 surgeons at 5 separate hospitals utilizing a mobile phone application survey. Surgeons recorded information about case type, intraoperative clinical outcomes such as blood loss and extent of resection, whether fluorescence visualization was used, as well as surgeon pain when compared to matched cases using conventional tools. RESULTS: A total of 155 neurosurgical cases were recorded in this multisite study, including 72% cranial cases and 28% spinal cases. Of the cranial cases, 76% were brain tumor resections (31% of which were brain metastases). Surgeons reported significantly less neck (P < 0.0001) and back (P < 0.0001) pain in cases when using the robotic exoscope compared with the conventional microscope or surgical loupes. Surgeons did not convert to a microscope in any case. CONCLUSIONS: The exoscope provides excellent delineation of tissue with high resolution. Surgeon pain was markedly reduced with the robotic exoscope when compared with conventional technology, which may reduce work-related injury and fatigue, potentially leading to better patient outcomes.

Interactions between programmable shunt valves and magnetically controlled growing rods for scoliosis.

OBJECTIVE: Although the advent of magnetic growing rod technology for scoliosis has provided a means to bypass multiple hardware lengthening operations, it is important to be aware that many of these same patients have a codiagnosis of hydrocephalus with magnet-sensitive programmable ventricular shunts. As the magnetic distraction of scoliosis rods has not previously been described to affect the shunt valve setting, the authors conducted an investigation to characterize the interaction between the two devices. METHODS: In this ex vivo study, the authors carried out 360 encounters between four different shunt valve types at varying distances from the magnetic external remote control (ERC) used to distract the growing rods. Valve settings were examined before and after every interaction with the remote control to determine if there was a change in the setting. RESULTS: The Medtronic Strata and Codman Hakim valves were found to have setting changes at distances of 3 and 6 inches but not at 12 inches. The Aesculap proGAV and Codman Certas valves, typically described as MRI-resistant, did not have any setting changes due to the magnetic ERC regardless of distance. CONCLUSIONS: Although it is not necessary to check a shunt valve after every magnetic distraction of scoliosis growing rods, if there is concern that the magnetic ERC may have been within 12 inches (30 cm) of a programmable ventricular shunt valve, the valve should be checked at the bedside with a programmer or with a skull radiograph along with postdistraction scoliosis radiographs.

Preconditioning with INC280 and LDK378 drugs sensitizes MGMT-unmethylated glioblastoma to temozolomide: Pre-clinical assessment.

Temozolomide (TMZ) therapy is the standard of care for patients with glioblastoma (GBM). Clinical studies have shown that elevated levels of DNA repair protein O (6)-methylguanine-DNA methyltransferase (MGMT) or deficiency/defect of DNA mismatch repair (MMR) genes is associated with TMZ resistance in some, but not all, GBM tumors. Another reason for GBM treatment failure is signal redundancy due to coactivation of several functionally linked receptor tyrosine kinases (RTKs), including anaplastic lymphoma kinase (ALK) and c-Met (hepatocyte growth factor receptor). As such, these tyrosine kinases serve as potential targets for GBM therapy. Thus, we tested two novel drugs: INC280 (Capmatinib: a highly selective c-Met receptor tyrosine kinase-RTK inhibitor) and LDK378 (Ceritinib: a highly selective anaplastic lymphoma kinase-ALK inhibitor), aiming to overcome TMZ resistance in MGMT-unmethylated GBM cells in in vitro cell culture models. Treatments were examined using MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay, caspase-3 assay and western blot analysis. Results obtained from our experiments demonstrated that preconditioning with INC280 and LDK378 drugs exhibit increased MMR protein expression, specifically MMR protein MLH1 (MutL Homolog 1) and MSH6 (MutS Homolog 6) and sensitized TMZ in MGMT-unmethylated GBM cells via suppression of ALK and c-Met expression. INC280 and LDK378 plus TMZ also induced apoptosis by modulating downstream signaling of PI3K/AKT/STAT3. Taken together, this data indicates that co-inhibition of ALK and c-MET can enhance growth inhibitory effects in MGMT-unmethylated cells and enhance TMZ sensitivity in-vitro, suggesting c-Met inhibitors combined with ALK-targeting provide a therapeutic benefit in MGMT-unmethylated GBM patients.

In Vitro Effect of Dovitinib (TKI258), a Multi-Target Angiokinase Inhibitor on Aggressive Meningioma Cells.

Background: Meningiomas represent ∼30% of primary central nervous system (CNS) tumors. Although advances in surgery and radiotherapy have significantly improved survival, there remains an important subset of patients whose tumors have more aggressive behavior and are refractory to conventional therapy. Recent advances in molecular genetics and epigenetics suggest that this aggressive behavior may be due to the deletion of the DNA repair and tumor suppressor gene, CHEK2, neurofibromatosis Type 2 (NF2) mutation on chromosome 22q12, and genetic abnormalities in multiple RTKs including FGFRs. Management of higher-grade meningiomas, such as anaplastic meningiomas (AM: WHO grade III), is truly challenging and there isn't an established chemotherapy option. We investigate the effect of active multi tyrosine receptor kinase inhibitor Dovitinib at stopping AM cell growth in in vitro with either frequent codeletion or mutated CHEK2 and NF2 gene.Methods: Treatment effects were assessed using MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay, western blot analysis, caspases assay, and DNA fragmentation assay.Results: Treatment of CH157MN and IOMM-Lee cells with Dovitinib suppressed multiple angiokinases-mainly FGFRs, leading to suppression of downstream signaling by RAS-RAF-MAPK molecules and PI3K-AKT molecules which are involved in cell proliferation, cell survival, and tumor invasion. Furthermore, Dovitinib induced apoptosis via downregulation of survival proteins (Bcl-XL), and over-expression of apoptotic factors (Bax and caspase-3) regardless of CHEK2 and NF2 mutation status.Conclusions: This study establishes the groundwork for the development of Dovitinib as a therapeutic agent for high-grade AM with either frequent codeletion or mutated CHEK2 and NF2, an avenue with high translational potential.

Pediatric Cranial Fasciitis: Discussion of Cases and Systematic Review of the Literature.

OBJECTIVE: Cranial fasciitis is a rare benign mass that typically presents in pediatric patients from 3 weeks to 6 years of age. It is classified as a subset of nodular fasciitis and was first reported in 1980. This study evaluates the literature for common characteristics that may affect diagnosis and treamtent. METHODS: We describe the case of a 13-month-old girl with a history of accidental head trauma 7 months before presentation and the case of a 5-month-old girl with an expansile skull lesion. We also performed a systematic review of the reported data on cranial fasciitis, including a total of 57 reported studies with 80 unique cases. RESULTS: There were 80 total cases reviewed in the literature. There was a male predominence, 1.75:1. The average age at presentation was 5.2 years. The most common causes for this lesion were idiopathic (65%), blunt trauma (14%) and radiation therapy (7%). Overall, there was a 9% recurrence rate following treatment. CONCLUSION: We report the characteristics at presentation, including, to the best of our knowledge, the first account of gender differences, and the treatment modalities used in the included studies and the implications in relation to the recurrence rates.

Single agent efficacy of the HDAC inhibitor DATS in preclinical models of glioblastoma.

PURPOSE/INTRODUCTION: Glioblastoma (GB) remains incurable despite aggressive chemotherapy, radiotherapy, and surgical interventions; immunotherapies remain experimental in clinical practice. Relevant preclinical models that can accurately predict tumor response to therapy are equally challenging. This study aimed to validate the effect of the naturally occurring agent diallyl trisulfide (DATS) in human GB in relevant pre-clinical models. METHODS: Ex vivo slice culture, in vivo cell line derived orthotopic xenograft and patient-derived orthotopic xenograft (PDX) animal models of GB were utilized to assess efficacy of treatment with DATS. RESULTS: Our results showed 72-h treatments of 25 µM DATS induced cell death in ex vivo human GB slice culture. We treated U87MG orthotopic xenograft models (U87MGOX) and patient-derived orthotopic xenograft models (PDX) with daily intraperitoneal injections of DATS for 14 days. Magnetic resonance (MR) imaging of mice treated with DATS (10 mg/kg) demonstrated reduced tumor size at 5 weeks when compared with saline-treated U87MGOX and PDX controls. Hematoxylin (H&E) staining demonstrated dose-dependent reduction in gross tumor volume with decreased proliferation and decreased angiogenesis. Western blotting showed that DATS was associated with increases in histone acetylation (Ac-Histone H3/H4) and activated caspase-3 in this novel preclinical model. Histological assessment and enzyme assays showed that even the highest dose of DATS did not negatively impact hepatic function. CONCLUSIONS: DATS may be an effective and well-tolerated therapeutic agent in preventing tumor progression and inducing apoptosis in human GB.

Chiari I malformation in children with transverse myelitis.

PURPOSE: Transverse myelitis (TM) is an acute inflammatory spinal cord injury. Asymptomatic Chiari I malformation (CMI) management is highly controversial, particularly when associated with a spinal syrinx. Here, we assess the occurrence of CMI in the pediatric TM population and management outcomes. METHODS: We performed a retrospective cohort study based on 61 consecutively identified pediatric TM cases over an -8-year period. We reviewed demographic characteristics, radiographic findings, presenting symptoms, and long-term outcomes. RESULTS: Eight CMI cases were identified within the TM cohort; all presented with TM by 16 months of age and affecting the cervical spinal cord. In three cases, CMI developed 15 months to 6 years after the onset of TM. One in 10 children with TM had CMI. CONCLUSION: These findings demonstrate a high prevalence of CMI in patients with TM. Large prospective clinical studies are needed to further investigate the natural history and recovery strategies of CMI involved with neuroinflammatory disorders.

Basilar artery occlusion in a child treated successfully with mechanical thrombectomy using ADAPT.

Acute ischemic stroke (AIS) in the pediatric population is rare. Furthermore, it is common for physicians to take significantly longer diagnosing a posterior circulation stroke in a child than in an adult. There are increasing case reports in the literature of treating AIS in children with intravenous tissue plasminogen activator, intra-arterial thrombolysis, and/or mechanical thrombectomy. We present the first case of pediatric AIS treated using a direct aspiration first pass technique (ADAPT) as a means of mechanical thrombectomy.

Re-Examining the Need for Tissue Diagnosis in Pediatric Diffuse Intrinsic Pontine Gliomas: A Review.

Diffuse intrinsic pontine glioma (DIPG) is a malignant brain tumor of childhood that carries an extremely poor prognosis. There are ~200-300 new cases diagnosed each year, [1, 2] and little progress has been made in changing the prognosis and outcome of the tumor since it was first documented in the literature in 1926 [3]. The median overall survival is 8-11 months [4], with an overall survival rate of 30% at 1 year, and less than 10% at 2 years [4]. This review will provide background information on DIPGs, a historical look at the trends in caring for DIPG, and current trends in diagnosis and treatment. By changing the way we care for these terminal tumors, we can work towards having a better understanding of the underlying molecular biology, and attempt to develop better chemotherapeutic tools to combat the disease.

Subcortical DNET in a Patient With an Enzymatic Deficiency: A Rare Case and Review of the Literature.

PURPOSE: This case report describes a toddler with a medical history of biotinidase deficiency who presented with atypical seizures due to a brain tumor. METHODS: This is a case report. RESULTS: Electroencephalogram revealed a frontal lobe mass, with magnetic resonance imaging confirmation of a mass extending from the frontal lobe into the genu and anterior corpus callosum. She underwent a near-total resection, and pathology identified a dysembryoplastic neuroepithelial tumor. The patient is now seizure free and clinically doing well. CONCLUSIONS: Children with biotinidase deficiency and atypical seizures should receive a full electroencephalogram evaluation, as brain tumors continue to be on the differential for seizures in this patient population.

Basilar artery occlusion in a child treated successfully with mechanical thrombectomy using ADAPT.

Acute ischemic stroke (AIS) in the pediatric population is rare. Furthermore, it is common for physicians to take significantly longer diagnosing a posterior circulation stroke in a child than in an adult. There are increasing case reports in the literature of treating AIS in children with intravenous tissue plasminogen activator, intra-arterial thrombolysis, and/or mechanical thrombectomy. We present the first case of pediatric AIS treated using a direct aspiration first pass technique (ADAPT) as a means of mechanical thrombectomy.

Enzyme replacement therapy for congenital hypophosphatasia allows for surgical treatment of related complex craniosynostosis: a case series.

Hypophosphatasia (HPP) is a rare inherited disorder of bone metabolism that results in the loss of function of the gene coding for tissue-nonspecific alkaline phosphatase (TNSALP). Patients with HPP have defective bone mineralization as well as craniosynostosis that can be seen in the infantile and childhood forms of this disease. Traditionally, HPP has had a poor prognosis, with few children surviving to exhibit the phenotype of clinical craniosynostosis that requires surgical intervention. Here, the authors report on new advancements in enzyme replacement therapy (ERT) for children affected by HPP, allowing these patients to survive and undergo surgery to address complex craniosynostosis. The authors discuss their case series of 4 HPP patients treated at their institution with ERT who have undergone successful surgical intervention for craniosynostosis. These children had no complications related to their surgeries and exhibited decreased neurological symptoms following cranial vault remodeling. This study reveals that ERT administered either pre- or post- operatively paired with cranial vault remodeling strategies can yield improved neurological outcomes in children affected by HPP.

High long-term symptomatic recurrence rates after Chiari-1 decompression without dural opening: a single center experience.

OBJECTIVE: We evaluated long-term outcomes of posterior fossa decompression (PFD) without duroplasty in consecutive patients with newly diagnosed Chiari-1 malformation. METHODS: We searched the institutional database for all adult patients who underwent Chiari decompression between 1995 and 2007. PFD was offered to all consecutive patients with Chairi-1 malformation during this time period. We excluded patients who underwent re-exploration after initial Chiari-1 decompression elsewhere. Besides the demographic variables, presenting symptoms, neurological and radiographic findings the clinical records were studied for long-term outcomes specifically symptomatic improvement. We defined symptomatic improvement as resolution of all presenting symptoms including pain and/or neurological deficits at the last follow-up. The factors associated with symptom recurrence were also analyzed. RESULTS: We identified 47 patients who underwent PFD for Chiari-1 malformation. Syringomyelia was noted in 36.2% of patients and the mean tonsilar herniation was 12.6mm. At a mean follow-up of 9.3 years, the symptomatic improvement rate was 60.6%. There were no operative complications. Repeat posterior fossa decompression was required for 31.9% patients with symptomatic recurrence at an average of 2.6 years after initial decompression. Fibrotic thickening overlying the dura mater was observed in one-third of these patients. CONCLUSIONS: This case series reports low complication but high long-term symptomatic recurrence rates adults with symptomatic Chiari-1 malformation undergoing PFD.