Chiari Malformation Research Articles

Syringomyelia: Retrospective Analysis of 30 Surgically Treated Patients from the Northeast of Brazil

Abstract Introduction Syringomyelia is a chronic disease characterized by the presence of intramedullary cavity. Chiari malformation (CM) and basilar impression (BI) are conditions usually associated with syringomyelia. Its prevalence has wide geographical variation, being higher in the Northeast of Brazil, making it relevant to study the subject in this region. Objective To analyze the frequency of signs, symptoms, and surgical aspects observed in patients undergoing decompressive treatment. Methods We performed a retrospective analysis of the medical records of patients diagnosed with syringomyelia who received decompressive surgical treatment in various hospitals in João Pessoa, Paraíba, between 1994 and 2021. Results Thirty patients were analyzed. Twenty-nine (96.7%) presented CM and 27 (90.0%) also presented BI. A wide variety of symptoms was found, with significant prevalence of muscle weakness, neck pain, and headache. Brevicollis, a finding considered typical of the Northeastern region and associated with craniocervical junction malformations, was present in 66.7%. The surgical technique used in 90% of patients was similar. Fourteen (46.7%) patients presented difficult craniocervical junction and 4 (13.3%) had occipital bone assimilation. Eighteen (60.0%) presented thickening of the arachnoid membrane. Postoperatively, there was clinical improvement in 21 patients (70%). Conclusions The sample majorly had CM and BI associated with syringomyelia. High prevalence of signs and symptoms related to the Brazilian northeastern phenotype was also found. Syringomyelia, therefore, has peculiarities in the population of the Northeast of Brazil that, when described, allow better understanding of the pathology in this group.

The Role of Neurophysiology in Managing Patients with Chiari Malformations.

Chiari malformation type 1 (CM1) includes various congenital anomalies that share ectopia of the cerebellar tonsils lower than the foramen magnum, in some cases associated with syringomyelia or hydrocephalus. CM1 can cause dysfunction of the brainstem, spinal cord, and cranial nerves. This functional alteration of the nervous system can be detected by various modalities of neurophysiological tests, such as brainstem auditory evoked potentials, somatosensory evoked potentials, motor evoked potentials, electromyography and nerve conduction studies of the cranial nerves and spinal roots, as well as brainstem reflexes. The main goal of this study is to review the findings of multimodal neurophysiological examinations in published studies of patients with CM1 and their indication in the diagnosis, treatment, and follow-up of these patients, as well as their utility in intraoperative monitoring.

Full-Endoscopic Technique for Posterior Fossa Decompression in Chiari Malformation.

Full-endoscopic techniques are well-described for spinal procedures. Although endoscopic-assisted techniques are reported for posterior fossa decompression (PFD) in Chiari malformation (CM), a full-endoscopic technique is yet to be reported in these patients. The aim of this study was to present and describe a full-endoscopic technique for PFD in patients with CM. Two patients diagnosed with CM were operated on by the full-endoscopic PFD technique. The patients consented to the procedure and to the publication of their image. An endoscope with an oval shaft cross-section with a diameter of 9.3 mm, a working length of 177 mm, a viewing angle of 20°, and a working channel of 5.6 diameters were used. Operative videos were recorded. The surgical steps were easily applied after the clear anatomic landmarks, such as the C1 posterior tubercle and the rectus capitis posterior minor muscles. The patients were followed up for 6 months. Both patients were symptom-free with a significant decrease in Visual Analog Scale score and a good functional outcome assessed by Chicago Chiari Outcome Scale after surgery without any complications. All the steps of the full-endoscopic technique for PFD described by the authors in their previous human cadaveric study were also feasible on patients with CM.

A C-Arm-Free Minimally Invasive Technique for Spinal Surgery: Cervical and Thoracic Spine.

Background and Objectives: C-arm-free MIS techniques can offer significantly reduced rates of postoperative complications such as inadequate decompression, blood loss, and instrumentation misplacement. Another advantageous long-term aspect is the notably diminished exposure to radiation, which is known to cause malignant changes. This study emphasizes that, in some cases of spinal conditions that require a procedural intervention, C-arm-free MIS techniques hold stronger indications than open surgeries guided by image intensifiers. Materials and Methods: This study includes a retrospective analysis and review of various cervical and thoracic spinal procedures, performed in our hospital, applying C-arm-free techniques. The course of this study explains the basic steps of the procedures and demonstrates postoperative and intraoperative results. For anterior cervical surgery, we performed OPLL resection, while for posterior cervical surgery, we performed posterior fossa decompression for Chiari malformation, minimally invasive cervical pedicle screw fixation (MICEPS), and modified Goel technique with C1 lateral mass screw for atlantoaxial subluxation. Regarding the thoracic spine, we performed anterior correction for Lenke type 5 scoliosis and transdiscal screw fixation for diffuse idiopathic skeletal hyperostosis fractures. Results: C-arm-free techniques are safe procedures that provide precise and high-quality postoperative results by offering sufficient spine alignment and adequate decompression depending on the case. Navigation can offer significant assistance in the absence of normal anatomical landmarks, yet the surgeon should always appraise the quality of the information received from the software. Conclusions: Navigated C-arm-free techniques are safe and precise procedures implemented in the treatment of surgically demanding conditions. They can significantly increase accuracy while decreasing operative time. They represent the advancement in the field of spine surgery and are hailed as the future of the same.

Assessing the Prevalence of Ectopic Cerebellar Tonsils and Accompanying Symptoms in Individuals with Various Headaches.

Chiari malformation exhibits well-defined clinical signs, symptoms, and incidence rates in clinical studies. However, cerebellar tonsil ectopia presents with ambiguous symptoms and undetermined incidence rates in numerous studies. Our objective was to determine the incidence of cerebellar tonsil ectopia in individuals with headaches and identify additional clinical symptoms. This aims to improve diagnosis accuracy for clinicians and neurologists, leading to more effective treatment approaches. A cross-sectional study conducted in 2022 included 2305 participants aged 4-78 years presenting with headache. Chiari malformation was diagnosed using magnetic resonance imaging (MRI) scans, with a definition of cerebellar tonsil herniation extending beyond 5mm into the cervical canal. The prevalence of Chiari malformation was 3.4%, with no significant gender difference (p = 0.72). There was a significant correlation between Chiari malformation and headache exacerbation due to the Valsalva maneuver (p < 0.001) and the presence of vertigo (p < 0.001). No significant association was found between Chiari malformation and accompanying symptoms such as nausea (p = 0.43), photophobia (p = 0.2), phonophobia (p = 0.52), and speech disorders (p = 0.45). These findings suggest a notable prevalence of Chiari malformation among headache patients and its association with specific headache characteristics, such as acute and occipital headaches, exacerbation by the Valsalva maneuver, and the co-occurrence of vertigo. These results underscore the need to consider Chiari malformation in the differential diagnosis of patients presenting with these specific headache features.

The Effect of Posterior Fossa Decompression Surgery on Brainstem and Cervical Spinal Cord Dimensions in Adults with Chiari Malformation Type 1

Posterior fossa decompression (PFD) surgery creates more space at the skull base, reduces the resistance to the cerebrospinal fluid motion, and alters craniocervical biomechanics. In this paper, we retrospectively examined the changes in neural tissue dimensions following PFD surgery on Chiari malformation type 1 adults. Measurements were performed on T2-weighted brain magnetic resonance images acquired before and 4months after surgery. Measurements were conducted for neural tissue volume and spinal cord/brainstem width at 4 different locations; 2 width measurements were made on the brainstem and 2 on the spinal cord in the midsagittal plane. Cerebellar tonsillar position (CTP) was also measured before and after surgery. Twenty-five adult patients, with a mean age of 38.9±8.8years, were included in the study. The cervical cord volume increased by an average of 2.3 ± 3.3% (P= 0.002). The width at the pontomedullary junction increased by 2.2 ± 3.5% (P < 0.01), while the width 10mm caudal to this junction increased by 4.2 ± 3.9% (P < 0.0001). The spinal cord width at the base of second cervical vertebra and third cervical vertebra did not significantly change after surgery. The CTP decreased by 60 ± 37% (P < 0.0001) after surgery, but no correlation was found between CTP change and dimension change. The brainstem width and cervical cord volume showed a modest increase after PFD surgery, although standard deviations were large. A reduction in compression after PFD surgery may allow for an increase in neural tissue dimension. However, clinical relevance is unclear and should be assessed in future studies with high-resolution imaging.

Real-life study of the use of oto-acoustic emissions in the diagnosis of intracranial hypotension

BackgroundThe diagnosis of spontaneous or post-traumatic intracranial hypotension (IH) mainly relies on clinical features and neuro-imaging. However, the results of brain and spine magnetic resonance imaging are not always contributive. There is an interest for other non-invasive procedures, able to confirm or refute the diagnosis. The use of oto-acoustic emissions (OAE) was previously reported on isolated cases of IH associated with endolymphatic hydrops (ELH). The aim of this study was to assess the real-life utilization of this electrophysiological method in a larger population of suspected IH. MethodsA retro-prospective cohort study was conducted from November 2013 to July 2022 in patients with a suspected or doubtful diagnosis of IH. They were assessed for ELH by recording bilateral distortion product of oto-acoustic emissions (DPOAE) in sitting then in supine position. ResultsAmong the 32 patients assessed, the diagnostic of IH was confirmed in 18 patients. An ELH was shown in 15 of them (83%), but also in seven other patients. They had several differential diagnoses: chronic migraine, Chiari malformation, rebound intracranial hypertension and perilymph fistula. ConclusionsThis procedure seems to be insufficient to exclude differential diagnosis when intracranial hypotension is suspected.

Endoscopic odontoidectomy for brainstem compression in association with posterior fossa decompression and occipitocervical fusion.

Endonasal endoscopic odontoidectomy (EEO) is an alternative to transoral surgery for symptomatic ventral compression of the anterior cervicomedullary junction (CMJ), allowing for earlier extubation and feeding. Because the procedure destabilizes the C1-2 ligamentous complex, posterior cervical fusion is often performed concomitantly. The authors' institutional experience was reviewed to describe the indications, outcomes, and complications in a large series of EEO surgical procedures in which EEO was combined with posterior decompression and fusion. A consecutive, prospective series of patients who underwent EEO between 2011 and 2021 was studied. Demographic and outcome metrics, radiographic parameters, extent of ventral compression, extent of dens removal, and increase in CSF space ventral to the brainstem were measured on the preoperative and postoperative scans (first and most recent scans). Forty-two patients (26.2% pediatric) underwent EEO: 78.6% had basilar invagination, and 76.2% had Chiari type I malformation. The mean ± SD age was 33.6 ± 3.0 years, with a mean follow-up of 32.3 ± 4.0 months. The majority of patients (95.2%) underwent posterior decompression and fusion immediately before EEO. Two patients underwent prior fusion. There were 7 intraoperative CSF leaks but no postoperative CSF leaks. The inferior limit of decompression fell between the nasoaxial and rhinopalatine lines. The mean ± SD vertical height of dens resection was 11.98 ± 0.45 mm, equivalent to a mean ± SD resection of 74.18% ± 2.56%. The mean increase in ventral CSF space immediately postoperatively was 1.68 ± 0.17 mm (p < 0.0001), which increased to 2.75 ± 0.23 mm (p < 0.0001) at the most recent follow-up (p < 0.0001). The median (range) length of stay was 5 (2-33) days. The median time to extubation was 0 (0-3) days. The median time to oral feeding (defined as, at minimum, toleration of a clear liquid diet) was 1 (0-3) day. Symptoms improved in 97.6% of patients. Complications were rare and mostly associated with the cervical fusion portion of the combined surgical procedures. EEO is safe and effective for achieving anterior CMJ decompression and is often accompanied by posterior cervical stabilization. Ventral decompression improves over time. EEO should be considered for patients with appropriate indications.

Letter to the Editor Regarding “The Dark Side of Chiari Malformation”

Letter to the Editor Regarding “The Dark Side of Chiari Malformation”

In Reply to the Letter to the Editor Regarding “The Dark Side of Chiari Malformation”

In Reply to the Letter to the Editor Regarding “The Dark Side of Chiari Malformation”

Pediatrik bir hastada eş zamanlı medulloblastoma ve Chiari Tip-I deformitesi

Concurrence of medulloblastoma and Chiari deformity (type-1) in a pediatric patient is extremely rarely seen. 10 years old girl. She had first complained of nausea, abdominal pain, and vomiting. She had a mild headache for three days. Computed tomography was taken. There were sequelae related to her previous illness and noticed the appearance of the left cerebellar tonsils down to the foramen magnum level and mild prominence in the third ventricle. Cranial imaging was performed with magnetic resonance imaging. There was a lesion as a solid mass, about 60 mm sized in the level right cerebellar, a cerebellar tonsil hernia (11 mm), and ventricular dilatation in magnetic resonance imaging. Histologically, the lesion was a classic type of medulloblastoma. The coexistence of two diseases may occur in the same patient. Magnetic resonance imaging, which indicates the craniovertebral junction can be used singly.Because MRG is the first method to be selected for diagnosis.

Foramen magnum decompression with cervical syringotomy for Chiari malformation type I with syringomyelia - A useful adjunct in selected cases.

Persistent or worsening syringomyelia after foramen magnum decompression (FMD) for Chiari I malformation (CIM) can be challenging to manage. We present a previously unpublished surgical technique of FMD with concomitant cervical syringotomy in selected patients. A retrospective analysis of prospectively collected data was carried out. Patients who underwent FMD and expansion duraplasty (FMDD) with concomitant syringotomy were collected. Three patients with CIM with high cervical syringomyelia who underwent FMDD with concurrent syringotomy were identified. All cases had an idiopathic CIM. Improvement in clinical symptoms was noticed in all patients. Early postoperative imaging (within 6 weeks-4 months) showed syrinx transverse diameter reduction in the range of 85-100%. There were no postoperative complications. FMDD with concurrent high cervical syringotomy through a standard approach in selected cases of CIM with high cervical syringes achieves clinical improvement without additional complications.

Sensitivity, Specificity, and Cutoff Identifying Optic Atrophy by Macular Ganglion Cell Layer Volume in Syndromic Craniosynostosis

PurposeDetermine sensitivity, specificity, and cut-off of macular ganglion cell layer (GCL) volume consistent with optic atrophy in children with syndromic craniosynostosis (CS). Investigate whether obstructive sleep apnea (OSA), Chiari malformation, history of elevated intracranial pressure (ICP), CS diagnosis, age, or sex independently alter GCL volume with CS. DesignRetrospective cross-sectional study. SubjectsPatients with syndromic CS evaluated at Boston Children’s Hospital (2010 – 2022) with reliable macular optical coherence tomography (OCT) scans. MethodsLatest ophthalmic examination that included OCT macula scans was identified. Age at examination, sex, ethnicity, best-corrected logMAR visual acuity, cycloplegic refraction, and funduscopic optic nerve appearance were recorded in addition to history of primary or recurrent elevated ICP, Chiari malformation and OSA. Spectral domain-OCT software quantified segmentation of macula retinal layers, and was manually checked. Main Outcome MeasuresPrimary outcome was determining sensitivity, specificity and optimal cutoff of GCL volume consistent with optic atrophy. Secondary outcome was determining possible independent association of previously elevated ICP, OSA, Chiari, CS diagnosis, logMAR acuity, age, or sex with altered GCL volume. ResultsMedian age at examination was 11.9 years (interquartile range (IQR), 8.5-14.8 years). Fifty-eight of 61 patients had reliable macula scans, 74% were female, and diagnoses were Apert (n=14); Crouzon (n=17); Muenke (n=6); Pfeiffer (n= 6); and Saethre-Chotzen (n=15). Optimal cutoff identifying optic atrophy was GCL volume <1.02mm3 with a sensitivity of 83% and specificity of 77%. Univariate analysis demonstrated significantly lower macular GCL volume with optic atrophy on fundus exam (P<0.001), Apert syndrome (P<0.001), history of elevated ICP (P=0.015), Chiari malformation (P=0.001), OSA (P<0.001), in males (P=0.027) and with worse logMAR acuity (-0.36, P<0.001). Multivariable median regression analysis confirmed that only OSA (P=0.005), optic atrophy on fundus exam (P=0.003), and worse logMAR acuity (P=0.042) independently associated with lower GCL volume. ConclusionsMacular GCL volume <1.02mm3 predicted optic atrophy in patients with CS with sensitive of 83% and specificity of 77%. OSA, a treatable often concomitant disorder, was independently associated with lower GCL volume. Surveillance for optic neuropathy by GCL volume proved effective in a population where cognitive skills can limit acquisition of other key ophthalmic measures.

Non-sedated fast spine magnetic resonance imaging in pediatric patients.

Traditional spine magnetic resonance imaging (MRI) protocols require sedation in young children and uncooperative patients. There is an increased interest in non-sedated pediatric MRI protocols to reduce risks associated with anesthetic agents and improve MRI access. To evaluate the image quality of pediatric non-sedated fast spine MRI. We retrospectively reviewed 69 pediatric non-sedated fast spine MRI exams performed in 57 patients. Two blinded readers provided image quality ratings for the evaluation of bones, cranio-cervical junction, cerebrospinal fluid (CSF) spaces, spinal cord, soft tissues, ligaments, and overall diagnostic quality on a 1-5 scale, and determined whether there was evidence of syringomyelia, abnormal conus medullaris position, or filum terminale abnormality. Mean patient age was 7.2years (age range ≤ 1-17). Indications included syringomyelia (n=25), spinal dysraphism (n=4), combination of both syringomyelia and spinal dysraphism (n=8), and other miscellaneous indications (n=32). The inter-observer agreement ranged between moderate and very good for each variable (Cohen's weighted kappa] range=0.45-0.69). The highest image quality ratings were given to CSF spaces (mean image quality=3.5/5 ± 0.8) and cranio-cervical junction evaluations (3.5/5 ± 0.9). Overall diagnostic quality was worst in the <5years group (P=0.006). Readers independently identified a cervical spinal cord syrinx in 6 cases, and 1mm spinal cord central canal dilation in one case. Readers agreed on the position of the conus medullaris in 92% of cases (23/25 cases). Non-sedated pediatric spine MRI can be an effective diagnostic test to evaluate for spine pathology, especially syringomyelia, Chiari malformation, and conus medullaris anatomy.

Chiari Malformation (CM) type III surgical management in infant: a case report

Background: Chiari Malformations (CM) is a collection of hindbrain abnormalities ranging from simple to complete agenesis of the cerebellum. Type III CM (CM III) is the rarest CM, with herniation of the cerebellum and brainstem into a posterior encephalocele and other intracranial anomalies. Reduction of the viable herniated brain, along with providing intracranial space and inadequate closure, often presents as the main problem. This case study aims to evaluate the Chiari malformation type III surgical management in infants. Case Presentation: A 16-day-old male infant with an intact congenital mass in the occipital, with no neurological deficit. Radiological examination shows a defect in the occipital skull consisting of cystic non-contrast enhancing lesion and parenchymal tissue herniated through the defect. The cele excision and defect closure were performed, and viable neural tissue was found inside the sac. Blossom flower-like trim expanded the fossa posterior space and put the viable neural tissue inside the intracranial room. The defect was then closed with a dura, periosteal patch, and tension-free two-layered scalp closure. Post-operative follow-up presented a good outcome, and 1-year follow-up showed good recovery, with developmental delay, following developmental rehabilitation. Conclusion: CM III is rare and has poor outcomes because neurological deficits and respiratory problems usually follow it. Operative management patient with CM III was presented with occipital encephalocele with no post-operative complication. Occipital bone reconstruction using a blossomed-flower-like technique could be considered to create adequate room for viable neural tissue.

Clinico-otoneurological assessment of the early postoperative outcome in surgical treatment of Chiari malformation and syringomyelia

although the pathology of Chiari malformation is extensively studied, many questions have not yet been solved. In particular, the clinical manifestations of this pathology have not been studied in detail entailing the lack of the unified approach for the optimal complex of the diagnostic workup and the selection of the optimal surgical intervention. These questions remain the point of discussion in the scientific literature. The present study is based on the retrospective analysis of the diagnostic findings and treatment outcomes of 59 patients – 24 males (40.7 %) and 35 females (59.3 %) – treated in the Department of spinal cord pathology of the State Institution "Romodanov Neurosurgery Institute, the National Academy of Medical Sciences of Ukraine" in 2010-2020. The age of the patients ranged from 16 to 50 years (36.9 ± 3.7 on the average). All patients were examined according to the conventional standards allowing for the assessment of the pre- and postoperative disease course. The following surgical interventions were provided: bone decompression for the inferior parts of the cerebellum at the upper cervical level; the recovery of the CSF flow at the region of craniovertebral junction; the expansion of the space in the fossa cranii posterior and/or craniovertebral junction. The data were processed and analyzed with the aid of STATISTICA 13 software. The quantitative variables were compared by non-parametric methods. The aim of the study was to analyze the preoperative and early postoperative clinico-otoneurological status in patients with Chiari malformation and syringomyelia. The clinical aspects of the disease were evaluated. Most clinical signs and symptoms in patients with Chiari malformation were associated with otolaryngological disturbances (hearing impairment, tinnitus, hoarseness, vertigo, etc.) and cerebellar signs (ataxia, nystagmus). Taking into account non-specific signs and symptoms of the disease, the otoneurological evaluation in these patients is undoubtedly of high importance for the preoperative differential diagnosis as well as the postoperative assessment of treatment outcome. The further study of the problem will allow us to timely diagnose Chiari malformation, to predict the course of the disease and the risk of the possible complications providing the clinicians with important information for decision-making on the optimal treatment strategy. The clinical and instrumental otoneurological examination is an important component of the systemic assessment of the clinical-and-functional status of patients with syringomyelia caused by Chiari malformation that allows for objectifying the dynamics of the otoneurological aspects of the disease in the course of the treatment.

Hemodynamic and Hydrodynamic Pathophysiology in Chiari Type 1 Malformations: Towards Understanding the Genesis of Syrinx.

The pathophysiology of this association of type 1 Chiari malformation (CM1) and syrinxes is still unknown. There is an alteration in the dynamics of neurofluids (cerebrospinal fluid, arterial and venous blood) during the cardiac cycle in CM1. Our objective is to quantify CSF or arterial blood or venous blood flow in patients with Chiari syndrome (CS) with and without syrinxes using phase-contrast MRI (PCMRI). We included 28 patients with CM1 (9 with syrinxes, 19 without). Morphological MRI with complementary PCMRI sequences was performed. We analyzed intraventricular CSF, subarachnoid spaces CSF, blood, and tonsillar pulsatility. There is a highly significant correlation (p < 0.001) between cerebral blood flow, cerebral vascular expansion volume and venous drainage distribution. Venous drainage distribution is significantly inversely correlated with oscillatory CSF volume at the level of the foramen magnum plane [-0.37 (0.04)] and not significantly correlated at the C2C3 level [-0.37 (0.05)] over our entire population. This correlation maintained the same trend in patients with syrinxes [-0.80 (<0.01)] and disappeared in patients without a syrinx [-0.05 (0.81)]. The distribution of venous drainage is an important factor in intracranial homeostasis. Impaired venous drainage would lead to greater involvement of the CSF in compensating for arterial blood influx, thus contributing to syrinx genesis.

The initial intracranial pressure spike phenomenon.

Elective use of intraparenchymal intracranial pressure (ICP) monitoring is a valuable resource in the investigation of hydrocephalus and other cerebrospinal fluid disorders. Our preliminary study aims to investigate ICP changes in the immediate period following dural breach, which has not yet been reported on. This is a prospective cohort study of patients undergoing elective ICP monitoring, recruited between March and May 2022. ICP readings were obtained at opening and then at 5-min intervals for a 30-min duration. Ten patients were recruited, mean age 45 years, with indications of a Chiari malformation (n = 5), idiopathic intracranial hypertension (n = 3) or other ICP-related pathology (n = 2). Patients received intermittent bolus sedation (80%) vs general anaesthesia (20%). Mean opening pressure was 22.9 mmHg [± 6.0], with statistically significant decreases present every 5 min, to a total reduction of 15.2 mmHg at 20 min (p = < 0.0001), whereafter the ICP plateaued with no further statistical change. Our results highlight an intracranial opening pressure 'spike' phenomenon. This spike was 15.2 mmHg higher than the plateau, which is reached at 20 min after insertion. Several possible causes exist which require further research in larger cohorts, including sedation and pain response. Regardless of causation, this study provides key information on the use of ICP monitoring devices, guiding interpretation and when to obtain measurements.

New minimally-invasive approach in adult for Chiari I malformation.

Chiari I malformation is defined by tonsillar herniation through the foramen magnum. There is no consensus on the treatment of Chiari malformation. A simple follow-up is recommended for asymptomatic cases. The classic approach is the midline sub-occipital craniotomy. For four years, we operated on six patients with Chiari malformation I using our endoscopic minimally invasive sub-occipital approach. We compared the results with six other patients operated by the classical sub-occipital approach. Patients operated by endoscopic approach had shorter hospital stays, and wounds healed faster and smoother. Mid-term results were similar in the two groups. This paper proposes a new endoscopic Minimally invasive paramedian sub-occipital approach for Chiari malformation I. Although the number of cases is limited, the results look promising. We need to gather more cases to have significant numbers to perform a global comparison between the two approaches and assess the advantages and disadvantages of each technique.

Global bibliometric and visual analysis of Chiari malformation

Chiari malformation (CM) is a type of disease in which the cerebellar tonsils extend downward due to abnormal development of the hindbrain. Still, recent bibliometric studies on CM are a blind spot. We conducted a bibliometric analysis of research over the past decade to explore the hot spots and trends in this field. We used VOSviewer, CiteSpace and Bibliometrix to perform a global bibliometric analysis of the articles from 2013 to 2022 on CM in the web of science (WOS) core collection. The query identified 2155 articles, of which most were published in the USA. Institutions like Akron University and the University of Washington published the most articles and were widely cited. Loth Francis and R. Shane Tubbs were the most productive authors on this topic. Besides, the top-cited article was also published by R.Shane Tubbs in J NEUROSURG-PEDIATR (2011). A great number of relevant studies focused on syringomyelia and surgical technique such as posterior fossa decompression. The CM field is still heating up and will continue to grow in popularity. Our findings offer a panoramic view of this research field for new researchers and policymakers.