Delayed spinal arachnoiditis with syringomyelia following aneurysmal subarachnoid haemorrhage: a case report with patient experience.

BACKGROUND AND IMPORTANCE: Syringomyelia, or the formation of fluid-filled cysts within the spinal cord, associated with delayed spinal arachnoiditis is an uncommon complication of aneurysmal subarachnoid haemorrhage. To date, about 18 cases have been reported in medical literature, with just two reported in patients under the age of 35 years. CLINICAL PRESENTATION: A 27-year-old female patient complained of sudden, severe headaches in the occipital region, nuchal rigidity, and drowsiness when she presented at our institution. A head computed tomography scan revealed intraventricular bleeding in the lateral and fourth ventricles with more extensive haemorrhaging in the frontal horns. A left posterior inferior cerebellar artery (PICA) aneurysm was confirmed via digital subtraction angiogram, and endovascular embolization was done. Two years later, the patient reported intense pain in the lower back along with symptoms suggestive of spinal cord compression. Spinal magnetic resonance imaging (MRI) showed spinal adhesions from C1 to L4, syringomyelia with some vasogenic oedema extending from T3 to T9 level, and a cyst in the lumbar region. Consequently, a right hemilaminectomy was performed along with microsurgical release of arachnoid adhesions and placement of a subdural drain. Radiological and symptomatic improvements were observed. Since then, the patient's clinical condition has remained stable during the past three years of follow-up visits. CONCLUSIONS: Literature on optimal treatment modalities and patient prognosis is scarce and debated. The time for symptom improvement depends on the level and extent of spinal cord involvement. Rehabilitation may be required for most patients, as complete symptomatic recovery may not be attainable.

Longitudinal Pulse-Synchronous Bouncing During Catheter Angiography-A Phenomenon Specific to Spinal Hemangioblastomas.

BACKGROUND: Spinal hemangioblastomas are often evaluated with catheter angiography for both workup and treatment planning. We report a unique longitudinal pulse-synchronous bouncing phenomenon observed during their angiographic evaluation and consider the association of pulse-synchronous bouncing with syringomyelia, another pathologic feature associated with hemangioblastomas. METHODS: Preoperative spinal angiograms and associated magnetic resonance imagings (MRIs) obtained over a 16-year period at a single institution were retrospectively evaluated. Magnetic resonance imaging (MRI) parameters included lesion and syrinx location and size. Angiograms were evaluated for bouncing phenomena. Student's t-test and Chi square test compared characteristics between groups. Linear regression analyses evaluated maximum amplitude of dynamic motion and any associated syrinx. RESULTS: Nineteen hemangioblastoma patients had preoperative angiograms available for review. Eight exhibited bouncing behavior. Between the dynamic and nondynamic cohorts, there was no difference in presence or volume of syrinxes. Lesions in the dynamic cohort trended towards a cervical location (75% vs. 36.3%, P = 0.10). No significant correlation was found between bouncing amplitude and syrinx size (R2 = 0.023). Dural contact may be related to this dynamic behavior since other high-flow lesions like AVMs do not demonstrate this phenomenon, and AVMs are pial-based and more likely to contact stationary dura. Here, there were fewer lesions abutting the thecal sac in the dynamic cohort (50% vs. 81.8%, P = 0.14). CONCLUSIONS: Though no significant relationship was established between this bouncing behavior and syrinx formation, noted trends included a greater range of motion for cervical lesions and limited motion in tumors abutting the thecal sac.

The role of occipital condyle and atlas anomalies on occipital cervical fusion outcomes in Chiari malformation type I with syringomyelia: a study from the Park-Reeves Syringomyelia Research Consortium.

OBJECTIVE: Congenital anomalies of the atlanto-occipital articulation may be present in patients with Chiari malformation type I (CM-I). However, it is unclear how these anomalies affect the biomechanical stability of the craniovertebral junction (CVJ) and whether they are associated with an increased incidence of occipitocervical fusion (OCF) following posterior fossa decompression (PFD). The objective of this study was to determine the prevalence of condylar hypoplasia and atlas anomalies in children with CM-I and syringomyelia. The authors also investigated the predictive contribution of these anomalies to the occurrence of OCF following PFD (PFD+OCF). METHODS: The authors analyzed the prevalence of condylar hypoplasia and atlas arch anomalies for patients in the Park-Reeves Syringomyelia Research Consortium database who underwent PFD+OCF. Condylar hypoplasia was defined by an atlanto-occipital joint axis angle (AOJAA) ≥ 130°. Atlas assimilation and arch anomalies were identified on presurgical radiographic imaging. This PFD+OCF cohort was compared with a control cohort of patients who underwent PFD alone. The control group was matched to the PFD+OCF cohort according to age, sex, and duration of symptoms at a 2:1 ratio. RESULTS: Clinical features and radiographic atlanto-occipital joint parameters were compared between 19 patients in the PFD+OCF cohort and 38 patients in the PFD-only cohort. Demographic data were not significantly different between cohorts (p > 0.05). The mean AOJAA was significantly higher in the PFD+OCF group than in the PFD group (144° ± 12° vs 127° ± 6°, p < 0.0001). In the PFD+OCF group, atlas assimilation and atlas arch anomalies were identified in 10 (53%) and 5 (26%) patients, respectively. These anomalies were absent (n = 0) in the PFD group (p < 0.001). Multivariate regression analysis identified the following 3 CVJ radiographic variables that were predictive of OCF occurrence after PFD: AOJAA ≥ 130° (p = 0.01), clivoaxial angle < 125° (p = 0.02), and occipital condyle-C2 sagittal vertical alignment (C-C2SVA) ≥ 5 mm (p = 0.01). A predictive model based on these 3 factors accurately predicted OCF following PFD (C-statistic 0.95). CONCLUSIONS: The authors' results indicate that the occipital condyle-atlas joint complex might affect the biomechanical integrity of the CVJ in children with CM-I and syringomyelia. They describe the role of the AOJAA metric as an independent predictive factor for occurrence of OCF following PFD. Preoperative identification of these skeletal abnormalities may be used to guide surgical planning and treatment of patients with complex CM-I and coexistent osseous pathology.

Multicenter comparison of Chiari malformation type I presentation in children versus adults.

OBJECTIVE: Treatment for Chiari malformation type I (CM-I) often includes surgical intervention in both pediatric and adult patients. The authors sought to investigate fundamental differences between these populations by analyzing data from pediatric and adult patients who required CM-I decompression. METHODS: To better understand the presentation and surgical outcomes of both groups of patients, retrospective data from 170 adults and 153 pediatric patients (2000-2019) at six institutions were analyzed. RESULTS: The adult CM-I patient population requiring surgical intervention had a greater proportion of female patients than the pediatric population (p < 0.0001). Radiographic findings at initial clinical presentation showed a significantly greater incidence of syringomyelia (p < 0.0001) and scoliosis (p < 0.0001) in pediatric patients compared with adult patients with CM-I. However, presenting signs and symptoms such as headaches (p < 0.0001), ocular findings (p = 0.0147), and bulbar symptoms (p = 0.0057) were more common in the adult group. After suboccipital decompression procedures, 94.4% of pediatric patients reported symptomatic relief compared with 75% of adults with CM-I (p < 0.0001). CONCLUSIONS: Here, the authors present the first retrospective evaluation comparing adult and pediatric patients who underwent CM-I decompression. Their analysis reveals that pediatric and adult patients significantly differ in terms of demographics, radiographic findings, presentation of symptoms, surgical indications, and outcomes. These findings may indicate different clinical conditions or a distinct progression of the natural history of this complex disease process within each population, which will require prospective studies to better elucidate.

Syringo-Subarachnoid Shunt with Tube Versus T-Tube via the Dorsal Root Entry Zone Approach for Eccentric Syringomyelia.

OBJECTIVE: This study compared the clinical therapeutic efficacy of syringo-subarachnoid shunt placement with direct tube and T-tube via the dorsal root entry zone (DREZ) approach for treatment of eccentric syringomyelia. METHODS: A retrospective study was performed of 41 patients with idiopathic or secondary eccentric syringomyelia from November 2011 to December 2022. Syringo-subarachnoid shunt placement with direct tube or T-tube via the DREZ approach was performed. The modified Japanese Orthopaedic Association low back pain scale was used to investigate the severity of clinical symptoms. Magnetic resonance imaging was used to investigate therapeutic efficacy（reduction of the cavity volume by >10% was considered an improvement and 50% was considered a significant improvement). RESULTS: Incision length of the spinal cortex in the direct tube group was shorter than in the T-tube group (3.10 ± 0.28 cm vs. 5.03 ± 0.19 cm), with a significant difference between the 2 groups (t = -52.56, P < 0.001). Modified Japanese Orthopaedic Association score 3 months postoperatively was significantly better than the preoperative score in both the direct tube group（t = 40.954, P < 0.001） and the T-tube group（t = 24.769, P < 0.001）. Statistical comparison revealed there was no difference in imaging improvement between the direct tube group and T-tube group 3 months (χ2 = 0.20, P = 0.655) and 12 months (χ2 = 0.21, P = 0.647) postoperatively. CONCLUSIONS: Syringo-subarachnoid shunt placement with direct tube via the DREZ approach for treatment of eccentric syringomyelia is safer than with T-tube via the DREZ approach due to smaller incision length and less of a space-occupying effect with same therapeutic efficacy.

Duraplasty using a combination of a pedicled dural flap and collagen matrix in posterior fossa decompression for pediatric Chiari malformation type 1 with syrinx.

PURPOSE: In posterior fossa decompression for pediatric Chiari malformation type 1 (CM-1), duraplasty methods using various dural substitutes have been reported to improve surgical outcomes and minimize postoperative complications. To obtain sufficient posterior fossa decompression without cerebrospinal fluid-related complications, we developed a novel duraplasty technique using a combination of a pedicled dural flap and collagen matrix. The objective of this study was to describe the operative nuances of duraplasty using a combination of a pedicled dural flap and collagen matrix in posterior fossa decompression for pediatric CM-1. METHODS: We reviewed the clinical and radiographic records of 11 consecutive pediatric patients who underwent posterior fossa decompression with duraplasty using a combination of a pedicled dural flap and collagen matrix followed by expansile cranioplasty for CM-1. The largest area of the syrinx and the size of the posterior fossa were calculated. RESULTS: The maximum syrinx area was reduced by a mean of 68.5% ± 27.3% from preoperatively to postoperatively. Four patients (36.4%) had near-complete syrinx resolution (> 90%, grade III reduction), five (45.5%) had 50% to 90% reduction (grade II), and two (18.2%) had < 50% reduction (grade I). The posterior fossa area in the midsagittal section increased by 8.9% from preoperatively to postoperatively. There were no postoperative complications, including cerebrospinal fluid leakage, pseudomeningocele formation, or infection. CONCLUSION: Duraplasty using a combination of a pedicled dural flap and collagen matrix in posterior fossa decompression is a promising safe and effective surgical technique for pediatric CM-1 with syrinx.

A complicated Chiari type 1 malformation and holocord syrinx as a likely cause for heel pain.

BACKGROUND: Chiari malformations are a rare group of rhomboencephalic abnormalities involving the brain, craniocervical junction and spine. They may manifest in a variety of clinical presentations which relate to the variable involvement of the cerebellum, brainstem, lower cranial nerves, spinal cord and altered CSF flow dynamics. METHOD: We report an unusual case of incidental diagnosis of a type I Chiari malformation with secondary cystic cerebellar tonsillar encephalomalacia and holocord syrinx following investigation of a 5YO girl presenting with heel swelling related to progressive neuropathic osteoarthropathy of the posterior calcaneal body and apophysis. RESULT: The child was treated with decompressive suboccipital craniectomy and C1 laminectomy and tonsillar resection. Cerebellar tonsillar gliosis and cystic degeneration were confirmed on histopathology. Referral for ongoing engagement with occupational and physical therapy. CONCLUSION: Most type I Chiari malformations in the paediatric population are incidental and asymptomatic. Neurological symptoms are typically mild and relate to altered CSF flow dynamics; however, we present a complex case of type I Chiari malformation with an unusual constellation of associated complications.

Natural history of Chiari I malformation with syrinx and dilatation of the central canal in the pediatric population: the CHEO experience.

PURPOSE: Given that syrinx is often considered an indication of surgery in children with Chiari I malformation (CM1), understanding of the natural history of these patients is very challenging. In this study, we investigate the natural history of children with CM1 that have syrinx and/or prominence of the central canal on presentation. METHODS: All pediatric Chiari I patients who had syrinx and/or prominence of the central canal who underwent MR imaging of the head and spine from 2007 to 2020 were reviewed. Patients were divided into 3 groups (early surgery, delayed surgery, and conservative management). We focused on those patients who did not initially undergo surgery and had at least 1 year of clinical follow-up. We assessed if there were any radiological features that would correlate with need for delayed surgical intervention. RESULTS: Thirty-seven patients met the inclusion criteria. Twenty-one patients were female and 16 were male. The mean age at presentation was 8.7 (5.8 SD). Fourteen (38%) patients had early surgical intervention, with a mean of 2.5 months after initial presentation, 8 (16%) had delayed surgery due to new or progressive neurological symptoms and 46% of patients did not require intervention during follow-up. The length of tonsillar herniation and the position of the obex were associated with the need of surgery in patients who were initially treated conservatively. CONCLUSION: In pediatric patients with CM1 with syringomyelia and prominence of the central canal, conservative treatment is initially appropriate when symptoms are absent or mild. Close follow-up of patients with CM1 and dilatation of the central canal who have an obex position below the foramen magnum and greater tonsillar herniation is suggested, as these patients show a trend towards clinical deterioration over time and may require earlier surgical intervention.

Retroflexed dens in paediatric Chiari 1 patients and implications: Single centre retrospective study.

INTRODUCTION: Chiari 1 malformation and hind brain hernia can be associated with skull base and craniocervical anomalies. One of the more recently associated anomalies is a retroverted or retroflexed odontoid process or dens. We conducted a retrospective study of our operated symptomatic and conservatively managed asymptomatic Chiari cohort to assess the impact of dens retroflexion on rate of revision or cerebrospinal fluid diversion following primary foramen magnum decompression (FMD). METHODS: We undertook a retrospective study of all foramen magnum decompression (FMD) cases for Chiari type 1 malformation performed over a 15-year period in a single tertiary paediatric neurosurgical unit. For comparison, non-operated asymptomatic Chiari cases were considered as reference cohort. Information gathered included: demographics, age, sex, length of cerebellar tonsils below McRae's line, pB-C2 distance (a line drawn perpendicular to one drawn between the basion and the posterior aspect of the C2 body), angle of retroflexion (angle formed between a line drawn through the odontoid synchondrosis and its intersection with a line drawn from the tip of the odontoid process) and angle of retroversion (angle formed between the line drawn from the base of C2 and its intersection with a line drawn from the tip of the odontoid process). Grade of retroflexion was measured using pre-operative mid-sagittal MR images and classified as grade 0 (> 90°), grade 1 (85°-89°); grade 2 (80°-84°) and grade 3 (< 80°). The rates for redo surgery or need for cerebrospinal fluid (CSF) diversion were obtained from clinical records and compared in the operated and non-operated groups. RESULTS: One hundred twenty-six Chiari 1 patients were included in this study with adequate imaging. Sixty-five patients were in the non-operated asymptomatic cohort with 61 patients in the operated symptomatic cohort. Mean age of non-operated cohort was 10.2 years with M:F ratio (30:35). Mean cerebellar tonsillar length below McRae's line was 10.3 mm. 7.7% of this cohort had associated syrinx. Mean angles of retroversion and retroflexion were 76 and 78°, respectively. Retroflexion grades included (9.2% grade 1, 35% grade 2 and 52.3% grade 3). pB-C2 distance was 6.8 mm. Mean age of operated cohort was 11.3 years, with M:F ratio (21:40). Mean cerebellar tonsillar length below McRae's line was 15 mm. 45.9% of this cohort had associated syrinx. Mean angles of retroversion and retroflexion were 73 and 74.5°, respectively. Retroflexion grades included (4.9% grade 1, 16.5% grade 2 and 78.6% grade 3). pB-C2 distance was 6.9 mm. No association was identified between retroflexion grade and rate of revision or CSF diversion following primary foramen magnum decompression. CONCLUSION: The operated Chiari 1 cohort had more retroflexed dens, longer tonsils and associated syrinx compared to the non-operated asymptomatic cohort.

[Clinical evaluation methods for craniovertebral junction abnormalities].

Craniovertebral junction malformation is a congenital malformation located in the foramen magnum and upper cervical spine, including bone and nerve malformation, resulting in motor and sensory disorders, cerebellar and lower cranial nerves, etc. The evaluation methods of clinical symptoms and efficacy of craniovertebral junction malformation are important for the surgical indications and effects, mainly including the evaluation of clinical symptoms and the quality of life. At present, the commonly used methods in clinical work and literature are the Japanese orthopaedic association scores, visual analogue scales, 36-item short-form health survey, etc. Most of these clinical evaluations are not aimed at craniovertebral junction diseases but focus on the description of a certain type of clinical symptoms. Chicago Chiari outcome scale and syringomyelia outcome scale of Xuanwu hospital are dedicated to Craniovertebral junction malformation, but more clinical studies are needed to prove their effectiveness. Based on the literature reports, this article reviewed the previous clinical evaluation methods of craniovertebral junction malformation and discusses their applications and limitations.

Clinical Relevance of Painful Congenital Early-onset Scoliosis: A Magnetic Resonance Image-based Study.

BACKGROUND: Back pain, as a clinical marker in scoliosis, has been associated with underlying pathology for many years, warranting further magnetic resonance imaging (MRI). Failures of segmentation, mixed defects, female gender, rib anomalies, congenital thoracic anomalies, and neurocutaneous markers are known risk factors for abnormal MRI pathology findings in patients with congenital early-onset scoliosis (Congenital-EOS). Yet, back pain has not been evaluated as a risk factor for underlying MRI pathology in patients with Congenital-EOS. This study aimed to assess back pain as a risk factor for underlying pathology in Congenital-EOS using MRI as a diagnostic tool. METHODS: A retrospective database review from the Pediatric Spine Study Group (PSSG) of all patients with Congenital-EOS who reported a back pain complaint, and underwent a spinal MRI study before surgical intervention was performed. Patients were divided into those with an underlying MRI pathology and those without. Demographics were compared between groups. RESULTS: From a total of 2355 patients with Congenital-EOS registered in PSSG, 107 patients reported a back pain complaint, with only 42 patients fulfilling the inclusion criteria (being evaluated with an MRI study). Overall group mean age was 8.1±4.5 years, with 25 of the 42 patients (60%) being females. Twenty-four of 42 patients (57%) had a comorbidity reported such as cardiac problems, musculoskeletal complaints, neurological deficits/myelopathy, gastrointestinal symptoms, developmental delay, respiratory problems, craniofacial abnormalities, and chromosomal conditions. An underlying MRI pathology was found in 21 of 42 patients with Congenital-EOS (50%) with back pain. The underlying MRI pathologies found were tethered spinal cord, spinal canal stenosis, syringomyelia, Arnold-Chiari malformation, and arachnoid cyst. CONCLUSIONS: Abnormal MRI findings are common in patients with Congenital-EOS who report back pain. Gender, age, major coronal curve angle, thoracic or lumbar predominance deformity, and comorbidities type or amount were not associated with abnormal MRI findings. LEVEL OF EVIDENCE: Level II-Prognostic study.

Total spine MRI for the preoperative evaluation of adolescent idiopathic scoliosis: part 1.

Adolescent idiopathic scoliosis is a commonly encountered condition often diagnosed on screening examination. Underlying, asymptomatic neural axis abnormalities may be present at the time of diagnosis. At certain institutions, total spine MRI is obtained preoperatively to identify these abnormalities. We provide a framework for the radiologist to follow while interpreting these studies. In part 1, we discuss Arnold Chiari malformations, syringomyelia, and the tethered cord. In part 2, we focus on spinal cord tumors, dysraphisms, to include diastematomyelia, and vertebral anomalies.

Management of Persistent Syringomyelia in Patients Operated for Chiari Malformation Type 1.

BACKGROUND: The treatment of persistent syringomyelia associated with Chiari malformation type 1 (CM1) is unclear. This study aims to evaluate the clinical and radiologic outcomes of syringo-subarachnoid shunt (SSS) as a treatment for persistent syringomyelia following posterior fossa decompression (PFD) for CM1. METHODS: Forty-nine cases treated for CM1 associated syringomyelia at a single center were analyzed, 17 of them undergoing reoperation due to persistent syrinx formation. The patients' demographic data, neurologic presentations, and radiologic results were analyzed, including cerebellar herniation, posterior fossa volume, the level at which the syrinx started and finished, the size and diameter of the syrinx. RESULTS: Seventeen patients underwent SSS placement, with 1 minor surgical complication (a cerebrospinal fluid leak) occurring and requiring revision. No morbidity or mortality was observed. Among these 17 reoperated patients, partial or complete resorption of the syrinx was observed in all cases. The results suggest that if the syrinx diameter is >10 mm at its thickest point, extends for more than 10 vertebrae, and starts from the upper cervical region and extends to the upper thoracic region, the syrinx may not regress after the first surgery and potentially predicting the need for a second operation before PFD. CONCLUSIONS: SSS placement for persistent syrinx following PFD for CM1 is a safe and effective surgical treatment method. These criteria may also help predict the need for a second surgery and the overall disease outcome for both the surgeon and patient.

Long-Term Impairment of the Blood-Spinal Cord Barrier in Patients With Post-Traumatic Syringomyelia and its Effect on Prognosis.

STUDY DESIGN: Cohort study. OBJECTIVE: The aim of this study was to explore the association between blood-spinal cord barrier (BSCB) markers and other factors associated with an unfavorable outcome among patients with post-traumatic syringomyelia (PTS) who achieved successful intradural adhesion lysis (IAL). SUMMARY OF BACKGROUND DATA: Only approximately half of PTS patients receiving IAL have a favorable outcome. PATIENTS AND METHODS: Forty-six consecutive patients with PTS and 19 controls (CTRL) were enrolled. All PTS patients underwent physical and neurological examinations and spinal magnetic resonance imaging before and 3 to 12 months after IAL. All patients underwent myelography before surgery. BSCB disruption was detected by increased intrathecal and serum concentrations of albumin, immunoglobulin (Ig)G, IgA, and IgM. A multivariable analysis was performed with a logistic regression model to identify factors associated with unfavorable outcomes. Receiver operating characteristic curves were calculated to investigate the diagnostic value of biomarkers. RESULTS: The ages and general health of the PTS and CTRL groups did not differ significantly. QAlb, IGAQ, IGGQ, and IGMQ was significantly higher in PTS patients than in controls ( P =<0.001). The degree of intradural adhesion was significantly higher in the unfavorable outcome group than in the favorable outcome group ( P <0.0001). QAlb, immunoglobulin (Ig)AQ, IGGQ, and IGMQ was significantly correlated with clinical status ( R =-0.38, P <0.01; R =-0.47, P =0.03; R =-0.56, P =0.01; R =-0.43, P =0.05, respectively). Higher QAlb before surgery (odds ratio=2.66; 95% CI: 1.134-6.248) was significantly associated with an unfavorable outcome. The receiver operating characteristic curve analysis demonstrated a cutoff for QAlb higher than 10.62 with a specificity of 100% and sensitivity of 96.3%. CONCLUSION: This study is the first to detect increased permeability and BSCB disruption in PTS patients. QAlb>10.62 was significantly associated with unfavorable clinical outcomes following intradural decompression. LEVEL OF EVIDENCE: Level III-prognostic.

Chiari Malformation Type 1 and Syringomyelia: Why Do Patients Claim for International Guidelines? Commentary on the 2021 Chiari and Syringomyelia Consensus Document.

The diagnosis of Chiari malformation type 1 (CM1) and Syringomyelia (Syr) has become increasingly common during the past few years. Contemporarily, the body of literature on these topics is growing, although randomized controlled studies on significant case series to drive guidelines are missing in the pediatric and adult populations. As a result of the different opinions about surgical indications and techniques raised by CM1-Syr, an increasing number of well-informed but disoriented patients is emerging. To bridge this gap, an International Consensus Conference on CM1-Syr held in Milan in November 2019 aimed to find a consensus among international experts, to suggest some recommendations that, in the near future, could lead to guidelines. Here, we comment on the most relevant recommendations about the definition, diagnosis, surgical management, failures and re-intervention, and outcome. We also focus on some "wrong" indications or techniques that, although widely disapproved by the experts, and negatively experienced by many patients, are still largely in use.

Evaluation of Adult and Pediatric Chiari Type 1 Malformation Patients: Do Consensus Documents Fit Everyday Practice?

The management of Chiari 1 malformation (CM1) and Syringomyelia (Syr) has shown many changes in surgical indications and techniques over time. The dedicated neurosurgical and neurological community recently planned to analyze the state of the art and find conduct uniformity. This led to international consensus documents on diagnostic criteria and therapeutic strategies. We aimed to evaluate, in a large, monocentric surgical series of adult and children CM1 patients, if the daily clinical practice reflects the consensus documents. Our series comprises 190 pediatric and 220 adult Chiari patients submitted to surgery from 2000 to 2021. The main indications for the treatment were the presence of Syr and symptoms related to CM1. While there is great correspondence with the statements derived from the consensus documents about what to do for Syr and symptomatic CM1, the accordance is less evident in CM1 associated with craniosynostosis or hydrocephalus, especially when considering the early part of the series. However, we think that performing such studies could increase the homogeneity of surgical series, find a common way to evaluate long-term outcomes, and reinforce the comparability of different strategies adopted in different referral centers.

Prospective, Longitudinal Study of Clinical Outcome and Morphometric Posterior Fossa Changes after Craniocervical Decompression for Symptomatic Chiari I Malformation.

BACKGROUND AND PURPOSE: The time course of changes in posterior fossa morphology, quality of life, and neurologic function of patients with Chiari I malformation after craniocervical decompression requires further elaboration. To better understand the pace of these changes, we longitudinally studied patients with Chiari I malformation, with or without syringomyelia, before and after the operation for up to 5 years. MATERIALS AND METHODS: Thirty-eight symptomatic adult patients (35 women, 3 men) diagnosed with Chiari I malformation only (n = 15) or Chiari I malformation and syringomyelia (n = 23) and without previous Chiari I malformation surgery were enrolled in a clinical study. Patients underwent outpatient study visits and MR imaging at 7 time points (ie, initial [before the operation], 3 months, 1 year, 2 years, 3 years, 4 years, and 5 years) during 5 years. The surgical procedure for all patients was suboccipital craniectomy, C1 laminectomy, and autologous duraplasty. RESULTS: Morphometric measurements demonstrated an enlargement of the CSF areas posterior to the cerebellar tonsils after the operation, which remained largely stable through the following years. There was a decrease in pain and improved quality of life after the operation, which remained steady during the following years. Reduction in pain and improved quality of life correlated with CSF area morphometrics. CONCLUSIONS: Most changes in MR imaging morphometrics and quality of life measures occurred within the first year after the operation. A 1-year follow-up period after Chiari I malformation surgery is usually sufficient for evaluating surgical efficacy and postoperative MR imaging changes.

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 .