Positive and negative predictors for good outcome after decompressive surgery for Chiari malformation type 1 as scored on the Chicago Chiari Outcome Scale

Cognitive-Affective Improvement on Cerebellar Neuropsychiatric Rating Scale Scores in Adults and Children After Decompression of Chiari Malformation Type I

BACKGROUND AND OBJECTIVES

This study evaluates the Cerebellar Neuropsychiatric Rating Scale (CNRS) in the preoperative and postoperative assessment of Chiari Malformation Type I (CM1).

METHODS

Adults and children with symptomatic CM1 undergoing surgical decompression completed the CNRS preoperatively (N = 87) and 8-24 months postoperatively (N = 56). Preoperative and postoperative total scores, as well as subdomains of attentional control, emotional control, autism spectrum, psychosis spectrum, and social skills, were compared using a paired t-test. Exploratory factor analysis was used to analyze the CNRS pattern in CM1. CNRS score correlation (Spearman-rank) with predecompression and postdecompression symptoms and surgical success measured by the Chicago Chiari Outcome Scale (CCOS) was assessed and with a standard neuropsychological test battery in a subset of patients (N = 24).

RESULTS

Preoperative and postoperative total CNRS scores reflected symptom reduction (mean (SD) 34.7 + 21.8 preoperative vs 29.3 + 22.9 postoperative, P = .01) with significant improvement in attentional and emotional control and autism spectrum subdomains. CNRS attentional control and autism spectrum presurgical subscores were negatively correlated with CCOS scores, indicating that worse performance on attention control and autism spectrum before surgery was associated with worse surgical outcomes. Although higher preoperative CNRS scores correlated with lower performance on a standardized neuropsychological test battery (ρ = 0.56, P = .003), presurgical complaints of neurocognitive symptoms correlated with improvement in reported CNRS attentional control (ρ = 0.37, P = .006). Four of the five hypothesized CNRS factors were observed in our CM1 sample. The CNRS took <15 minutes to administer in all cases.

CONCLUSION

CNRS in CM1 demonstrates preoperative cognitive-affective dysregulation with postsurgical improvement. The observed correlations of predecompression and postdecompression CNRS scores with cognitive symptoms, neuropsychological performance, and the CCOS add a novel clinical tool for the perioperative routine assessment of the Chiari patient, offering a unique focus on patient-reported perspectives of cognitive-affective symptoms.

Phase-contrast magnetic resonance imaging-based predictive modelling for surgical outcomes in patients with Chiari malformation type 1 with syringomyelia: a machine learning study

AIM

Prospective outcome prediction plays a crucial role in guiding preoperative decision-making in patients with Chiari malformation type I (CM-Ⅰ) with syringomyelia. Here, we aimed to develop a predictive model for postoperative outcomes in patients with CM-Ⅰ with syringomyelia by integrating clinical and radiological parameters.

MATERIALS AND METHODS

We retrospectively analysed the data of 151 adult patients diagnosed with CM-I with syringomyelia who underwent posterior fossa decompression surgery. Clinical outcomes were assessed using the Chicago Chiari Outcome Scale (CCOS). Predictors were investigated using bivariate and multiple linear regression analyses. Five factors were used to build seven independent machine learning (ML) models: Cat Boost classifier (CatBoost), random forest, light gradient boosting machine, decision tree classifier, logistic regression, K neighbours classifier, and support vector machine. The dataset was randomly divided into training (n = 121, 80%) and test (n = 30, 20%) sets. Model performance was evaluated using precision, recall, F-1 score, and area under the curve (AUC). Shapley additive explanations (SHAP) was used to interpret the feature significance.

RESULTS

The best independent model was the CatBoost model, with an AUC of 0.9583 and an accuracy of 0.9097. The cross-validation results indicated that the accuracy of the CatBoost model was 0.8667. The SHAP plot revealed the important ranking of the features affecting the CCOS score as syrinx diameter, preoperative symptom duration, gait instability, peak diastolic velocity at the foramen magnum, and age.

CONCLUSION

We successfully developed a model to predict the prognosis of patients with CM-Ⅰ with syringomyelia after posterior fossa decompression.

Clinical efficacy of surgery for patients with Chiari malformation type I with syringomyelia: posterior fossa decompression versus posterior fossa decompression with resection of tonsils

Background

The optimal surgical approach for treating Chiari malformation type I (CM-I) with syringomyelia remains a topic of debate. Key areas of controversy include the extent of decompressive craniectomy, the necessity of subarachnoid exploration, and whether to excise the herniated tonsils. In this study, we present our perspectives on these contentious issues through a retrospective analysis of the clinical efficacy of posterior fossa decompression with resection of tonsils (PFDRT) compared to posterior fossa decompression (PFD).

Methods

We conducted a retrospective analysis of clinical data from 162 patients diagnosed with CM-I and syringomyelia who underwent surgical intervention at the Affiliated Hospital of Xuzhou Medical University between January 2017 and December 2022. Among these, 58 patients underwent PFD, while 104 received PFDRT. The efficacy of the treatments was evaluated using the Chicago Chiari Deformity Prognosis Scale (CCOS) at 6 months post-surgery, with scores ranging from 13 to 16 indicating a favorable prognosis. Furthermore, the improvement of syringomyelia was assessed through magnetic resonance imaging (MRI) at the six-month follow-up.

Results

Six months post-surgery, according to the Chiari Clinical Outcome Scale (CCOS) score, the improved rates for the PFD and PFDRT groups were 56.9 and 78.8%, respectively. Additionally, the recovery rates for syringomyelia in these groups were 55.2 and 76%, respectively. Statistically significant differences were observed in both the rates of favorable prognosis and syringomyelic improvement between the two groups (p < 0.05). The incidence of complications, including fever, cerebrospinal fluid leakage, intracranial infection, and incision infection, did not differ significantly between the groups (p > 0.05).

Conclusion

Our findings indicate that PFDRT yields superior outcomes in syringomyelia improvement and favorable prognoses compared to PFD, while maintaining comparable postoperative complication rates.

A Prospective Study of CSF Flow Dynamics Across Foramen Magnum in Adult Chiari Malformation/Syringomyelia Complex and its Clinical Correlation with Outcomes after Surgery

Introduction  Chiari I malformation refers to cerebellar tonsillar descent below the foramen magnum and is frequently associated with syringomyelia. Prior cerebrospinal fluid (CSF) flow studies correlated the clinical severity of these lesions with general flow velocity or bulk flow at the foramen magnum; however, these techniques have not assessed the effect on surgical outcomes. The study aims to present clinical and radiological factors and CSF flow parameters (pre- and postoperative) that affect the surgical outcome. Materials and Methods  The institutional ethics committee approved the study. We collected the prospective clinical data, including pre- and postoperative symptoms. Functional grades were determined along with the change in clinical improvement based on clinical examination notes, the change in functional grade was calculated, and the radiologic data were analyzed according to the degree of clinical improvement. The surgical procedure included suboccipital bony decompression with duroplasty. Patients were followed up at 1 month, 3 months, and 1 year. Results  There were a total of 25 patients. The mean age of the patients was 45.52 ± 13.37 years, with 40% being males and 60% being females. After the surgery, there was a significant increase in the anterior and posterior CSF flows at the foramen magnum. Most had a resolution in the headache and sensory symptoms, while the lower cranial nerve and motor symptoms had a minor resolution at follow-up. Age, sex, and headache do not correlate with the outcome or syrinx improvement. Motor power in the lower limb (preintervention) and syrinx shape (preintervention) were significantly associated with the variable "anterior flow at the foramen magnum" (preintervention; p  < 0.05). Average flow, cervicomedullary angle (postintervention), sensory symptom progression, and CSF flow change anterior to the foramen magnum were significantly associated with the variable "anterior flow at the foramen magnum" (postintervention; p  < 0.05). Conclusion  Even after surgery, persistent foramen magnum CSF outflow obstruction has a robust negative correlation with the outcome. The Chiari outcome predictability index has shown a significant correlation with patient outcomes and can be used to inform patients about the expected outcome. The results of the present study will be helpful in stratifying patients according to their desired outcomes.

Impacts of type 1 Chiari malformation on elderly

Background

This study aims to evaluate the surgical outcomes of elderly patients with Chiari malformation (CM) who underwent suboccipital craniectomy (SC) with duraplasty (DP) or dural splitting (DS). The focus is on symptom relief, changes in syrinx size, hospital admission duration, and postoperative complications.

Methods

A retrospective study was performed to evaluate the outcomes of elderly CM patients who underwent SC with DP or dural splitting (DS). Patients older than 60 years who underwent posterior fossa decompression (PFD) together with DP or DS who underwent surgery from 1989 to 2022 were included in the study. Patients were divided into two categories based on their surgical approach - SC with DP and SC with dural splitting (DS) surgery. Demographic details, co-morbidities, clinical features, management details, Chicago Chiari Outcome Scale (CCOS), complications, and follow-up details were obtained.

Results

Of the seven patients, five were females, and two were males. The mean age at the time of the operation is 65.14 years. Among the seven patients, six had syrinx, with a mean diameter of 6.17 mm; one patient had hydrocephalus, and one had scoliosis. All the patients underwent PFD; six patients also underwent DP, and one patient underwent DS. The median CCOS at the time of discharge is 13.

Conclusion

In elderly CM patients, surgery improved symptoms for most but led to reoperations in two cases. Despite a slight increase in syrinx diameter and a drop in the CCOS score, better outcomes were associated with smaller syrinxes. Further research is needed to optimize treatment strategies for this population.

Long-term outcomes following posterior fossa decompression in pediatric patients with Chiari malformation type 1, a population-based cohort study

OBJECTIVE

Posterior fossa decompression for Chiari malformation type I (Chiari 1) is effective and associated with a low risk of complication. However, up to 20% of patients may experience continued deficits or recurring symptoms after surgical intervention. For pediatric patients, there are no established tools to predict outcomes, and the risk factors for unfavorable postoperative outcomes are poorly understood. Hence, our aim was to investigate baseline data and early postoperative predictors of poor outcomes as determined by the Chicago Chiari outcome scale (CCOS).

METHODS

All pediatric patients (< 18 years) receiving a posterior fossa decompression for Chiari 1 between the years of 2005 and 2020 at the study center were eligible for inclusion. Patients with congenital anomalies were excluded.

RESULTS

Seventy-one pediatric patients with a median age of 9 years were included. Most patients (58%) were females. Chiari 1 was associated with syringomyelia (51%), scoliosis (37%), and hydrocephalus (7%). Perioperative complications occurred in 13 patients (18%) of which two required additional procedures under general anesthesia. On multivariable proportional odds logistic regression, motor deficits (OR: 0.09; CI95%: [0.01-0.62]; p = 0.015), and surgical complications (OR: 0.16; CI95%: [0.41-0.66]; p = 0.011) were significant predictors of worse outcomes. The presence of syringomyelia was identified as a predictor of better outcomes (OR: 4.42 CI95% [1.02-19.35]; p = 0.048). A persistent hydrocephalus during the early postoperative period after posterior fossa decompression was a strong predictor of worse long-term CCOS (OR: 0.026; CI95%: [0.002-0.328]; p = 0.005).

CONCLUSION

Results from this study indicate that the existence of motor deficits and syringomyelia prior to surgery, and surgical complications and persistent hydrocephalus despite posterior fossa decompression, were useful predictors of long-term outcome.

Predictors of poor functional outcomes in adults with type I Chiari Malformation: Clinical and surgical factors assessed with the Chicago Chiari Outcome Scale over long-term follow-up

OBJECTIVE

This study aimed to identify clinical and surgical features associated with poor long-term postoperative outcomes in patients diagnosed with Type I Chiari Malformation (CMI) treated with posterior fossa decompression with duroplasty (PFDD), with or without tonsillar coagulation.

METHODS

This retrospective, single-center study included 107 adult patients with CMI surgically treated between 2010 and 2021. The surgical technique involved a midline suboccipital craniectomy, C1 laminectomy, durotomy, arachnoid dissection, duroplasty, and tonsillar coagulation until 2014, after which tonsillar coagulation was discontinued. Postoperative outcomes were assessed using the Chicago Chiari Outcome Scale (CCOS) at a median follow-up of 35 months. Clinical, surgical, and neuroimaging data were analyzed using the Wilcoxon signed-rank test, Cox regression analysis, and Kaplan-Meier survival curves to identify predictors of poor functional outcomes.

RESULTS

Of the 107 patients (mean age 43.9 years, SD 13), 81 (75.5 %) showed functional improvement, 25 (23.4 %) remained unchanged, and 1 (0.9 %) experienced worsened outcomes. Cephalalgia, bilateral motor weakness, and bilateral paresthesia were the most frequent initial symptoms. Tonsillar coagulation was performed in 31 cases (28.9 %) but was clinically associated with higher rates of unfavorable outcomes. The Wilcoxon signed-rank test indicated that long-term follow-up CCOS was significantly higher than postoperative CCOS (Z = -7.678, p < 0.000). Multivariate Cox analysis identified preoperative bilateral motor weakness (HR 6.1, 95 % CI 1.9-18.9; p = 0.002), hydrocephalus (HR 3.01, 95 % CI 1.3-6.9; p = 0.008), and unilateral motor weakness (HR 2.99, 95 % CI 1.1-8.2; p = 0.033) as significant predictors of poor outcomes on a long-term follow-up.

CONCLUSION

This study highlights the high rate of functional improvement in CMI patients following PFDD. Preoperative motor weakness and hydrocephalus were significant predictors of poor long-term outcomes. Tonsillar coagulation did not demonstrate a clear clinical benefit and may be associated with worse outcomes. Our findings suggest that careful preoperative assessment and selection of surgical techniques are crucial for optimizing patient outcomes.

The impact of social determinants of health on early outcomes after adult Chiari surgery

We sought to identify social determinants of health (SDoH) for adult patients undergoing Chiari decompression surgery and to analyze their association with postoperative outcomes, including length of stay (LOS), return to the system within 30 days, and the Chicago Chiari Outcomes Score (CCOS). This is a retrospective study of adult patients who underwent Chiari decompression surgery between June 2021 and January 2023. Data was gathered through electronic medical record review and telephone surveys. Descriptive statistics were used to evaluate demographics of all patients meeting inclusion criteria. Fisher's exact tests and logistic regression were used for data analysis. A total of 37 patients underwent Chiari decompression (23 CCOS/SDoH survey respondents): 48% bony decompression only, 30% bony decompression plus intradural exploration, and 22% occipitocervical fusion. Seven patients (30%) had a LOS > 2 days, 1 patient (4%) required inpatient rehabilitation postoperatively, 4 patients (17%) returned to the system within 30 days, 10 patients (43%) had an extremely favorable CCOS (15-16), and 11 patients (48%) reported interaction with a Chiari support group. Mean follow-up was 9.5 months. Patients with occipitocervical fusion were more likely to have a LOS > 2 days (p = 0.03), patients who exercised ≥ 3 days per week were more likely to have a favorable CCOS (p = 0.04), and patients who participated in a Chiari support group were less likely to have a favorable CCOS (p = 0.03). Chiari decompression plus occipitocervical fusion may be associated with increased LOS. While more frequent exercise may be associated with better post-surgical outcomes, participation in a Chiari support group may be correlated with worse outcomes.

Complication Avoidance in Chiari Malformation Surgery

Posterior fossa decompression for symptomatic Chiari malformation is an effective and frequently performed procedure, but it does carry risks of significant complications including cerebrospinal fluid leak and craniocervical instability. Patients sometimes do not improve or worsen after decompression, which may discourage neurosurgeons from performing Chiari decompression surgery. In this chapter, management strategies and surgical approaches are discussed that minimize the risks of complications and maximize favorable outcomes in Chiari malformation surgery.

A different perspective on the dilemma of durotomy or duraplasty in Chiari type 1 malformation surgery

PURPOSE

Symptomatic Chiari type 1 malformation (CIM) patients may elect to be treated; however, choosing the optimum surgical method remains problematic: posterior fossa decompression with duraplasty (PFDD) or without duraplasty (PFD). Many studies have compared these surgical methods from several perspectives. We looked at soft tissue density (STD) at the foramen magnum to add another perspective to the comparison of PFD with PFDD.

MATERIALS AND METHODS

Eighty-six patients who underwent surgery in our clinic were included in the study. We examined preoperative and postoperative MR images taken in the 1st year. We obtained the foramen magnum area (FMA) and soft tissue at the level of the foramen magnum. The STD within the foramen magnum was calculated as the percentage ratio of soft tissue area (STA) to FMA. Anteroposterior diameters of the syrinx cavities in sagittal T2 sections were measured preoperatively and at 1-year postoperatively. Measurements were double-blind and were performed by the neurosurgeon and by the neuroradiologist.

RESULTS

There was no statistically significant difference between the postoperative FMA increases, STA changes, STD changes in patients who underwent PFD and PFDD. In this study, there was no statistically significant difference between PFD and PFDD in terms of syrinx changes.

CONCLUSIONS

The medium-term anatomical outcome following craniovertebral decompression for CIM, is no different whether performed PFD or PFDD.

Combined Cerebrospinal Fluid Hydrodynamics and Fourth Ventricle Outlet Morphology to Improve Predictive Efficiency of Prognosis for Chiari Malformation Type I Decompression

OBJECTIVE

To identify the morphological characteristics together with cerebrospinal fluid (CSF) hydrodynamics on preoperative magnetic resonance imaging that improve the prediction of foramen magnum decompression (FMD) treatment outcome for Chiari malformations type I (CM-I) patients compared with the CSF hydrodynamics-based model.

METHODS

This retrospective study included CM-I patients who underwent FMD, phase-contrast cine magnetic resonance, and static MR between January 2018 and March 2022. The relationships of the preoperative CSF hydrodynamic quantifications derived from phase-contrast cine magnetic resonance and morphological measurements from static magnetic resonance imaging, clinical indicators with different outcomes, were analyzed with logistic regression analysis. The outcomes were determined using the Chicago Chiari Outcome Scale. The predictive performance was evaluated with receiver operating characteristic, calibration, decision curves and area under the receiver operating characteristic curve, net reclassification index, and integrated discrimination improvement and was compared with CSF hydrodynamics-based model.

RESULTS

A total of 27 patients were included. 17 (63%) had improved outcomes and 10 (37%) had poor outcomes. The peak diastolic velocity of the aqueduct midportion (odd ratio, 5.17; 95% confidence interval: 1.08, 24.70; P = 0.039) and the fourth ventricle outlet diameter (odd ratio, 7.17; 95% confidence interval: 1.07, 48.16; P = 0.043) were predictors of different prognoses. The predictive performance improved significantly than the CSF hydrodynamics-based model.

CONCLUSIONS

Combined CSF hydrodynamic and static morphologic MR measurements can better predict the response to FMD. A higher peak diastolic velocity of the aqueduct midportion and broader fourth ventricle outlet were associated with satisfying outcomes after decompression in CM-I patients.

Low versus High Intracranial Compliance in Adult Patients with Chiari Malformation Type 1-Comparison of Long-Term Outcome After Tailored Treatment

BACKGROUND

In patients with Chiari malformation type 1 (CMI) presenting with low intracranial compliance (ICC), foramen magnum decompression (FMD) often fails and the complication rate may be higher. We therefore routinely perform a preoperative assessment of ICC from intracranial pressure measurement. Patients with low ICC are treated with ventriculoperitoneal shunt (VPS) before FMD. In this study, we assess the outcome of patients with low ICC, compared with patients with high ICC treated with FMD alone.

METHODS

We reviewed the clinical and radiologic data of all consecutive patients with CMI treated between April 2008 and June 2021. ICC was assessed by overnight measurement of the pulsatile intracranial pressure: mean wave amplitude (MWA) above a previously defined threshold for abnormality was considered a surrogate marker for low ICC. The outcome was scored by Chicago Chiari Outcome Scale.

RESULTS

Of 73 patients, 23 with low ICC (average MWA 6.8 ± 1.2 mm Hg) received VPS before FMD, whereas 50 with high ICC (average MWA 4.4 ± 1.0 mm Hg) received only FMD. After a mean follow-up of 78.7 ± 41.4 months, 96% of all patients subjectively improved. The mean Chicago Chiari Outcome Scale score was 13.1 ± 2.2. Enlargement of cerebrospinal fluid space in the foramen magnum was achieved in 95% and regression of syringomyelia in 74% of cases. We found no significant difference in outcome between the patients with low and high ICC.

CONCLUSIONS

By identifying patients with CMI associated with low ICC and tailoring their treatment by VPS before FMD, we achieved favorable clinical and radiologic outcomes comparable to those with high ICC.

Management of Adult Chiari I Patients Based on CSF Flow Magnetic Resonance Imaging: Experience of Two Neurosurgical Centers

BACKGROUND AND STUDY AIMS

 Chiari malformation type 1 (CM1) is one of the most discussed neurosurgical disorders. No consensus exists how to manage adult CM1 patients. We aimed to evaluate all adult CM1 patients consecutively managed at our institutions and discuss our approach based on the phase-contrast (PC) magnetic resonance imaging (MRI).

PATIENTS AND METHODS

 The medical charts of adult patients diagnosed with CM1 at two referral neurosurgical centers between 2010 and 2017 were reviewed. The patients were either managed conservatively or surgically. We evaluated the patients clinically with the Chicago Chiari Outcome Scale (CCOS). The radiologic diagnosis was based on both craniocervical and PC-MRI.

RESULTS

 Ninety adult CM1 patients were managed conservatively. Conservative treatment failed in 5 of these 90 patients. Seventy-two patients (including those 5 patients who did not benefit from conservative treatment) underwent posterior fossa decompression with duraplasty. Eighty-five patients (94.4%) from the conservative group and 61 patients (84.7%) from the surgical group were treated successfully. An aqueductal stroke volume (ASV) value of 12 µL was found as the cutoff value for surgical candidates. A strong positive correlation between the increase in ASV values and clinical improvement was observed.

CONCLUSIONS

 PC-MRI can help in the management and follow-up of adult CM1 patients. Conservative management is possible in selected symptomatic CM1 patients with a high ASV (ASV > 15 µL). Surgery should be considered in patients with an ASV ≤ 12 µL. CM1 patients with ASV ≤12 to >15 μL require close follow-up. Long-standing symptoms, severe sleep apnea, symptoms influencing functionality, and syrinx are factors that affected outcomes negatively.

Exploring the prognostic differences in patients of Chiari malformation type I with syringomyelia undergoing different surgical methods

Background

The best surgical treatment of Chiari malformation patients with syringomyelia remains controversial, and whether cerebellar tonsillectomy should be performed has not been decided.

Objective

To evaluate the efficacy of posterior fossa decompression with duraplasty (PFDD) and Posterior fossa decompression with resection of tonsils (PFDRT) in patients of Chiari malformation type I (CM-I) with syringomyelia and explore relevant factors affecting prognosis.

Patients and methods

We retrospectively analyzed 182 adult patients of CM-I with syringomyelia who underwent PFDD or PFDRT over a 6-year period, and analyzed their clinical manifestations, imaging features, and follow-up data. Clinical outcomes were assessed using the Chicago Chiari Outcome Scale (CCOS), and imaging outcomes were assessed using the syrinx remission rate. Difference comparisons were performed to compare the differences between different surgical groups. Influencing factors associated with outcome were investigated using bivariate analysis and multiple linear regression analysis.

Results

There were statistically significant differences in CCOS score (p = 0.034) and syrinx remission rates (p = 0.046) between the PFDRT group and the PFDD group after surgery. Regression analysis showed that preoperative motor dysfunction, cerebellar-related symptoms and different surgical methods may have influenced the CCOS score and that brainstem-related symptoms and age may have influenced the syrinx remission rates in the total patient group (p < 0.05). Regression analysis showed that the duration of symptoms, cerebellar-related symptoms and preoperative syrinx diameter may have influenced the CCOS score and that the preoperative cerebellar tonsillar hernia distance may have influenced the postoperative syrinx remission rate in the PFDRT group (p < 0.05). Age and length of hospital stay may have influenced the CCOS score, and brainstem-related symptoms and age may have influenced the syrinx remission rates in the PFDD group (p < 0.05).

Conclusion

This study showed that the CCOS score in the PFDRT group was better than that in the PFDD group. Preoperative motor dysfunction, cerebellar-related symptoms, and different surgical methods in patients of CM-I with syringomyelia affected postoperative CCOS score. Both the duration of symptoms and the age of the patients should be actively considered as factors influencing prognosis. Symptomatic CM-I patients with syringomyelia should undergo surgical treatment as early as possible.

Possible predictive clinical and radiological markers in decision making for surgical intervention in patients with Chiari Malformation type 1

BACKGROUND

The first aim of this study was to compare the clinical data and posterior fossa morphometry obtained during the admission to the hospital between control group individuals (who had not Chiari Malformation (CM) type 1) and CM type 1 patients treated surgically or not. The second aim was to create a valid and reliable scale that can predict the decision-making for surgical intervention simply and easily in these patients.

MATERIALS

Medical data and radiological images of 70 CM type 1 patients during their admission to the hospital were compared with the data of 69 control group individuals.

RESULTS

Conservative treatment and/or follow-up was applied to 58 (82.9%) patients, and 12 (17.1%) patients underwent surgery. ROC analysis showed that the presence of myelopathy, tonsillar herniation >8 mm, Chamberlain line >84 mm, McRae line >44.50 mm, and odontoid process-McRae line angle <10.50 degrees could be used as predictive markers in decision-making for surgical intervention (p < 0.05). Logistic Regression analysis revealed that symptoms severity, and McRae line value would be the 'best parameters' in decision-making for surgical intervention (p < 0.05). A scale named the CHIASURG scale developed using this study's parameters showed that the parameters of 'depth of tonsillar herniation', 'Chamberlain line', and 'McRae line' could predict the surgical intervention risk.

CONCLUSION

It was found that symptoms severity and McRae line value could be used as predictive markers in decision-making for surgical intervention. Additionally, it was concluded that a new scale called CHIASURG could predict surgical intervention risk validly and reliably.

Influence of clivo-axial angle on outcome after foramen magnum decompression in adult symptomatic Chiari type 1 malformation

OBJECTIVE

A significant number of patients with Chiari type 1 malformation (CM1) have abnormal clivo-axial angle (CXA) without other radiographic indicators of basilar invagination or craniovertebral junction (CVJ) instability. This study aimed to investigate whether abnormal CXA alone influences postoperative outcomes among patients who underwent foramen magnum decompression (FMD).

METHODS

A total of 44 adult patients with symptomatic CM1 undergoing FMD without CVJ fixation were enrolled. Preoperative clinical characteristics and radiographic measurement include the CXA as well as the radiographic indicators of basilar invagination and instability were recorded. The univariate and multivariate binary logistic regression tests were used to identify the potential prognostic factors for favorable outcomes.

RESULTS

Eighteen patients (41%) and 26 patients (59%) were divided into unfavorable and favorable outcome groups, respectively. Baseline demographic and imaging characteristics were similar between the two patient groups. The mean CXA was 132.3 ± 15.8 and 145 ± 13.6 degrees in the unfavorable and favorable groups, respectively (P = 0.091). In the favorable outcome group, the proportion of patients with CXA > 135 degrees was significantly higher than that of the unfavorable outcome group (77% vs. 44%; P = 0.05). The CXA > 135 degrees was found to be the only independent predictor associated with favorable outcomes (adjusted risk ratio 2.16; 95% CI 1.01-4.76; P = 0.047).

CONCLUSION

The preoperative CXA of greater than 135 degrees was identified as a prognostic factor associated with a favorable outcome at one-year follow-up after FMD among adult patients with symptomatic CM1 without basilar invagination or CVJ instability. This factor should be incorporated into preoperative considerations.

Conservative Treatment of Chiari Malformation Type I Based on the Phase-Contrast MRI: A Retrospective Study

BACKGROUND

The phase-contrast magnetic resonance image (PC-MRI) use is interestingly increased in diagnosis and follow-up patients with Chiari Type I Malformation (CM1). The current study aimed to elaborate the benefits of conservative treatment by evaluating consecutively treated adult patients with CM1 who were selected on basis of the PC-MRIs.

METHODS

Medical records of patients diagnosed with CM1 were retrospectively reviewed at two neurosurgical centers spanning eight years (2010-2017). Adult patients with CM1, who were treated conservatively and met study criteria, were selected to be the core sample for this study. Between-groups (benefited vs non-benefited) comparisons were performed to understand the factors that may affect the outcomes.

RESULTS

Ninety (68 females and 22 males) adult patients received conservative treatment for CM1. The mean age was 40.6. Headaches and pinprick loss were the most commonly recorded symptoms and clinical findings which were recorded in 58 (64.4%) and 31 (34.4%) patients, respectively. Eleven patients were presented with a syrinx. The mean aqueductal stroke volume (ASV) was 16.5 μl. The conservative treatment failed in treating five (5.6%) patients who underwent surgical intervention. The means of ASV in the benefited and non-benefited groups were 16.7 and 13.2 μl, respectively (p=0.004).

CONCLUSION

Conservative approaches (prescriptive medications, physical therapy, Pilates, and swimming) can improve the life quality of non-surgical candidate adult patients with CM1. Conservative treatment can be useful in selected patients with variably CM1 (ASV=16.7 μl). The presence of heavy sleep apnea or/and functional symptoms were prognostic factors that were affected the conservative treatment negatively.

Precise Management of Chiari Malformation with Type I

Diagnosis of Chirai malformation type I (CM-I) is based on magnetic resonance imaging of the brain or cervical spinal cord. The main goal of surgery is to relieve the blockage to the free pulsatile flow of cerebrospinal fluid beyond the foramen magnum and to stop the progression of a syringomyelia. Despite recent advances in imaging and surgery, even today, there is no consensus on optimal management of CM-I. Ongoing focus is devoted to a better consideration of the pathophysiology of CM-I and the development of more effective medical and surgical treatments. It is hoped that proposed algorithm helps the neurosurgeon to provide a precise management for patients with CM-I in advance.

The factors affecting the outcomes of conservative and surgical treatment of chiari i adult patients: a comparative retrospective study

BACKGROUND

The prognosis of the Chiari malformation type 1 (CM1) demonstrates a variant spectrum that varies from full recovery to complicated worse neurological disability.

OBJECTIVE

To investigate the factors affecting the outcomes of conservative and surgical treatment for CM1 by evaluating adult patients consecutively managed at our institutions.

MATERIALS AND METHODS

We retrospectively reviewed the medical records of patients diagnosed with CM1 at two reference neurosurgical centers for eight years (2010-2017). We selected all CM1 adult patients who managed conservatively or surgically as the core sample for this study. For clinical evaluation, we used a Chicago Chiari Outcome Scale (CCOS). For radiological assessment, we adopted both craniocervical and contrast-phase MRIs. We investigate factors such as age, sex, pretreatment symptoms, symptoms duration, and radiological findings in both groups.

RESULTS

Ninety patients were treated conservatively. After a progression, five of them were treated surgically later and included in a total of 72 patients who underwent decompressive surgery. We successfully managed 85 patients (94.4%) of the conservative group and 64 patients (88.9%) of the surgical group. We found that patients with aqueductal stroke volume (ASV) of 12 µl are surgical candidates. We observed a strong positive correlation between clinical improvement and the increase in ASV values.

CONCLUSIONS

ASV≤12 µl is a significant predictor for surgical intervention. The presence of heavy sleep apnea or/and functional symptoms, tonsillar herniation >13.4 mm on coronal images, low ASV, long symptom durations, and a syrinx are the independent prognostic factors that affected outcomes negatively.

Surgical Outcomes of Adult Chiari Malformation Type 1: Experience at a Tertiary Institute

Background

Chiari type I malformation (CM1) is a herniation of the caudal cerebellum and/or medulla oblongata into the upper spinal canal, occurring in pediatric and adult populations. We aimed to analyze the surgical outcomes of adult patients with CM1 consecutively treated with a posterior fossa decompression and duraplasty (PFDD) in a tertiary institution.

Patients and methods

We retrospectively reviewed the medical charts of 45 adult patients with CM1 who underwent PFDD at the Neurosurgery Department of our institution between January 2012 and December 2017. Radiological evaluation was based on pre- and postoperative syrinx/cord ratio, syrinx length, and regression of the ectopic cerebellar tonsils on coronal and sagittal magnetic resonance imaging (MRI) images, and clinical assessment of the patients was performed with the Chicago Chiari Outcome Scale (CCOS).

Results

Of the 45 patients included in the study, 25 (four men, 21 women) were diagnosed with symptomatic CM1 with an age average of 36.6±11.4 (18-66) years. Headache was the most common symptom (72.0%), while pinprick losses were prevalent in 13 (52.0%) patients. The mean postoperative CCOS score was 14.7±2.0 (8-16). Symptoms improved in 20 patients (80.0%) at the last follow-up. The mean regression in ectopic tonsils on midsagittal and coronal images were 9.1±1.8 (range: 0-16.5) mm and 8.3±1.2 (0-12.0) mm, respectively (p<0.05). The syrinxes had regressed completely or significantly in 7 (87.5%) of eight patients with syrinx.

Conclusion

Our findings showed that PFDD is sufficient to relieve most of the major symptoms and resolve the syrinx cavity without additional surgical interventions. The CCOS keeps its measurability of assessment of the clinical outcomes. A reliable radiological evaluation should be performed on midsagittal and coronal MRI images.

Long-term surgical outcome of Chiari type-I malformation-related syringomyelia: an experience of tertiary referral hospital

OBJECTIVE

Syringomyelia is a common condition seen in patients with Chiari type-I malformation (CM1). The purpose of this retrospective study was to evaluate the long-term clinical and radiological outcomes of posterior fossa decompression with duraplasty (PFDD) with coagulation of tonsillar ectopia in consecutive surgically treated adult patients with CM1-related syringomyelia (CRS).

METHODS

Over 9 years' duration (1993-2001), medical charts of diagnosed patient with CM1 at our neurosurgical center were reviewed retrospectively. This study included adult patients with CM1 who had syringomyelia and underwent PFDD with coagulation of tonsillar ectopia surgery. The differences between the pre- and postoperative syrinx/cord ratio (S/C), the syrinx length, and the regression of herniated cerebellar tonsils on coronal and midsagittal MRIs were evaluated.

RESULTS

A total of 87 surgical procedures (46 primary operations, 7 ventriculoperitoneal shunts, and 34 additional operations) for CRS were performed on 24 males and 22 females. The mean preoperative S/C was 0.59 ± 0.12. The means of regression in herniated cerebellar tonsils on mid-sagittal and coronal images were 11.8 ± 2.3 mm and 10.2 ± 2.2 mm (p < 0.0001), respectively. 35 (76.1%) patients were discharged after showing signs of recovery or improvement. Different complications occurred in 16 (34.8%) patients. Negative correlations were noticed between postoperative recovery/improvement and the long symptoms' duration, the herniated tonsils' extent, S/C, and the persistence of the herniated tonsils on the coronal images.

CONCLUSION

Early diagnosis of patients with CRS can improve surgical outcomes. Due to its efficacy in resolving clinical symptoms and syrinx cavities, PFDD is still an optimal surgical approach for CRS.

Extradural decompression versus duraplasty in Chiari malformation type I with syrinx: outcomes on scoliosis from the Park-Reeves Syringomyelia Research Consortium

OBJECTIVE

Scoliosis is common in patients with Chiari malformation type I (CM-I)-associated syringomyelia. While it is known that treatment with posterior fossa decompression (PFD) may reduce the progression of scoliosis, it is unknown if decompression with duraplasty is superior to extradural decompression.

METHODS

A large multicenter retrospective and prospective registry of 1257 pediatric patients with CM-I (tonsils ≥ 5 mm below the foramen magnum) and syrinx (≥ 3 mm in axial width) was reviewed for patients with scoliosis who underwent PFD with or without duraplasty.

RESULTS

In total, 422 patients who underwent PFD had a clinical diagnosis of scoliosis. Of these patients, 346 underwent duraplasty, 51 received extradural decompression alone, and 25 were excluded because no data were available on the type of PFD. The mean clinical follow-up was 2.6 years. Overall, there was no difference in subsequent occurrence of fusion or proportion of patients with curve progression between those with and those without a duraplasty. However, after controlling for age, sex, preoperative curve magnitude, syrinx length, syrinx width, and holocord syrinx, extradural decompression was associated with curve progression > 10°, but not increased occurrence of fusion. Older age at PFD and larger preoperative curve magnitude were independently associated with subsequent occurrence of fusion. Greater syrinx reduction after PFD of either type was associated with decreased occurrence of fusion.

CONCLUSIONS

In patients with CM-I, syrinx, and scoliosis undergoing PFD, there was no difference in subsequent occurrence of surgical correction of scoliosis between those receiving a duraplasty and those with an extradural decompression. However, after controlling for preoperative factors including age, syrinx characteristics, and curve magnitude, patients treated with duraplasty were less likely to have curve progression than patients treated with extradural decompression. Further study is needed to evaluate the role of duraplasty in curve stabilization after PFD.

Preoperative measurements on MRI in Chiari 1 patients fail to predict outcome after decompressive surgery

Background

The purpose of our study was to research the parameters of magnetic resonance imaging (MRI) that would predict the outcome of surgery in patients with Chiari 1 malformation (CM1) and to evaluate changes in MRI parameters after surgery.

Methods

Fifty-one patients (19 children, 13 adolescents, and 19 adults) operated on due to CM1 in Oulu University Hospital between 2004 and 2018 were evaluated. Seventeen parameters were measured from the preoperative MRI and 11 from the postoperative MRI. The correlations between the MRI parameters and the clinical variables before and after surgery were analyzed.

Results

The majority (88.2%) of the patients had favorable surgical outcomes. Postoperatively, subjective symptoms improved in 88.6% of the patients and syringomyelia in 81.8%. The location of the cerebellar tonsils, when measured in relation to the C2 synchondrosis or the end plate, postoperatively moved cranially in 51.0% (n = 26), did not change in 27.4% (n = 14), and moved caudally in 21.6% (n = 11) of the patients. However, neither the location of the tonsils nor any other parameters measured from pre- or postoperative MRI correlated with the patients’ symptoms or surgical outcomes.

Conclusions

No specific parameters on preoperative MRI evaluation were predictive of the outcome of surgery, emphasizing clinical examination in surgical decision-making. Furthermore, the postoperative MRI parameters did not correlate with the surgical outcomes. Thus, routine postoperative imaging is suggested only for patients with preoperatively diagnosed syringomyelia or worsening of symptoms.

Long-term outcomes of surgical management in subtypes of Chiari malformation

Objective: Chiari malformations (CMs) are a heterogeneous group of disorders defined by anatomic anomalies of the cerebellum, brainstem, and craniovertebral junction (CVJ). The aims of this study are to establish the demographic and clinical features, incidence, surgical procedures, and outcomes in large series of old and new subtypes of CMs.Material and Methods: All patients were evaluated and operated on for CM-0, 1, and 1.5 between 1985 and 2016. The patients were grouped into various subtypes. Demographic data, additional diseases, clinical features, surgical procedures, complications and outcomes were recorded.Results: 191 patients who underwent various surgical procedures were evaluated. Their mean age was 37.21 ± 9.89. We detected 15 cases of CM-0 (7.8%), 121 cases of CM-1 (63.4%), 55 cases of CM-1.5 (28.8%). In total there were 191 cases, and 220 surgical procedures were performed. 29 (13.2%) of all surgical procedure was reoperations and secondary operations. SM Cyst is found to be decreased in 72 (76.5%) patients, unchanged in 14 (14.8%) and increased in 8(8.5%) of 94 patients radiologically. Clinical outcomes are better for 131 (65.8%), same for 31 (16.2%) and worse for 9 (15%).Conclusion: This study with 172 patients is a large series that includes CM-0, 1, and 1.5 subtypes. CM-1.5 also differs for symptom presentation and durations from CM-1. There are more neurological abnormalities in patients with SM. CVD alone are an effective, useful and safe surgical procedure for CM-0, CM-1 and CM-1.5. Surgical procedure, SM existence, and symptom duration have powerful effects on outcomes.

Type I Chiari Malformation Without Concomitant Bony Instability: Assessment of Different Surgical Procedures and Outcomes in 73 Patients

OBJECTIVE

Posterior fossa decompression is the treatment of choice in type 1 Chiari malformation (CM-1) without bony instability. Although surgical fixation has been recommended by a few authors recently, comparative studies to evaluate these treatment strategies using objective outcome tools are lacking.

METHODS

Seventy-three patients with pure CM-1 (posterior fossa bony decompression [PFBD], n = 21; posterior fossa bony and dural decompression [PFBDD], n = 40; and posterior fixation [PF], n = 12) underwent a postoperative outcome assessment using Chicago Chiari Outcome Score (CCOS). Logistic regression analysis detected predictors of an unfavorable outcome.

RESULTS

Minimally symptomatic patients generally underwent a PFBD while most of the clinically severe patients underwent a PFBDD (p = 0.049). The mean CCOS score at discharge was highest in the PF (12.0 ± 1.41) and lowest in PFBDD group (10.98 ± 1.73, p = 0.087). Patients with minimal preoperative clinical disease severity (adjusted odds ratio [AOR], 4.58; 95% confidence interval [CI], 1.29-16.31) and PFBDD (AOR, 7.56; 95% CI, 1.70-33.68) represented risks for an unfavorable short-term postoperative outcome. Though long-term outcomes (CCOS) did not differ among the 3 groups (p = 0.615), PFBD group showed the best long-term improvements (mean follow-up CCOS, 13.71 ± 0.95), PFBDD group improved to a comparable degree despite a poorer short-term outcome while PF had the lowest scores. Late deteriorations (n = 3, 4.1%) occurred in the PFBDD group.

CONCLUSION

Minimally symptomatic patients and PFBDD predict a poor short-term postoperative outcome. PFBD appears to be a durable procedure while PFBDD group is marred by complications and late deteriorations. PF does not provide any better results than posterior fossa decompression alone in the long run.

Pre-operative headaches and obstructive hydrocephalus predict an extended length of stay following suboccipital decompression for pediatric Chiari I malformation

PURPOSE

For young children and adolescents with Chiari malformation type I (CM-I), the determinants of extended length of hospital stay (LOS) after neurosurgical suboccipital decompression are obscure. Here, we investigate the impact of patient- and hospital-level risk factors on extended LOS following surgical decompression for CM-I in young children to adolescents.

METHODS

The Kids' Inpatient Database year 2012 was queried. Pediatric CM-I patients (6-18 years) undergoing surgical decompression were identified. Weighted patient demographics, comorbidities, complications, LOS, disposition, and total cost were recorded. A multivariate logistic regression was used to determine the odds ratio for risk-adjusted LOS. The primary outcome was the degree patient comorbidities or post-operative complications correlated with extended LOS.

RESULTS

A total of 1592 pediatric CM-I patients were identified for which 328 (20.6%) patients had extended LOS (normal LOS, 1264; extended LOS, 328). Age, gender, race, median household income quartile, and healthcare coverage distributions were similar between the two cohorts. Patients with extended LOS had significantly greater admission comorbidities including headache symptoms, nausea and vomiting, obstructive hydrocephalus, lack of coordination, deficiency anemias, and fluid and electrolyte disorders. On multivariate logistic regression, several risk factors were associated with extended LOS, including headache symptoms, obstructive hydrocephalus, and fluid and electrolyte disorders.

CONCLUSIONS

Our study using the Kids' Inpatient Database demonstrates that presenting symptoms and signs, including headaches and obstructive hydrocephalus, respectively, are significantly associated with extended LOS following decompression for pediatric CM-I.

Posterior Fossa Decompression and superficial durotomy rather than complete durotomy and duraplasty in the management of Chiari 1

Objective: We aimed to evaluate the effectiveness and reliability of posterior fossa decompression (PFD) and superficial durotomy in patients who underwent surgery for Chiari malformation type 1 (CM1).Materials and Methods: Our study included 54 patients with the diagnosis of CM1 who had surgery between January 2012 and June 2019. The patients were divided into two groups according to the surgical technique applied. Group 1 included 10 patients who underwent classic PFD and duraplasty, and Group 2 included 44 patients who underwent PFD and superficial durotomy surgery. Pre- and postoperative clinical signs and symptoms of each patient were recorded. Simultaneously, morphometric measurements were compared from computed tomography (CT) and magnetic resonance (MRI) images taken pre- and postoperatively. The data of the two groups were compared.Results: Of the 54 patients, 18 were male, and the mean age was 37.51 ± 15.14. A statistically significant difference was found between the pre- and postoperative morphometric measurements of the subarachnoid distance, craniocervical angle, syringomyelia, and hydrocephalus at the cerebellum level in Group 2 patients who underwent PFD and superficial durotomy surgery (p < 0.05). When morphometric measurements and clinical signs and symptoms of both groups were compared, no significant difference was found (p > 0.05). There was a 92% improvement in clinical signs and symptoms postoperatively. The complications seen in Group 1 decreased to a minimum in Group 2.Conclusion: We believe that a minimally invasive surgical method is superior to avoid major complications. We also found PFD and superficial durotomy shorten the duration of the patient's hospital stayAbbreviations: C1: cervical vertebra 1C2: cervical vertebra 2CM: Chiari malformationCM1: Chiari malformation type 1CSF: cerebrospinal fluidCT: computed tomographyMRI: magnetic resonance imagingPFD: posterior fossa decompressionUSG: ultrasonography.

Soft tissue density within the foramen magnum, a predictor for surgical intervention in pediatric patients with Chiari malformation type I

OBJECTIVE

Chiari malformation type I (CMI) is diagnosed as herniation of the cerebellar tonsils by at least 5 mm below the foramen magnum. However, the degree of tonsillar herniation is a poor predictor of the need for decompression surgery. Exploration for an alternative morphological predictor for surgical intervention could provide greater insight into the development of an appropriate treatment plan for these patients. To investigate this issue, the authors calculated the soft tissue density within the foramen magnum as a measure of impaction of the cerebellar tonsils. Soft tissue density within the foramen magnum and degree of tonsillar herniation were then assessed for their correlation with the need for surgical intervention.

METHODS

The authors conducted a retrospective, longitudinal chart review of pediatric patients with CMI. Those who had undergone surgical intervention were considered symptomatic and those who had been treated conservatively, as asymptomatic. Soft tissue density was found by dividing the soft tissue occupancy of the foramen magnum (brainstem and cerebellar tonsils) by the total area of the bony foramen magnum. The predictive value of these two measurements for the need of surgery was determined.

RESULTS

Of the 465 patients seen for CMI at the authors' institution between July 1, 2011, and May 31, 2017, 80 underwent surgical intervention and 385 were asymptomatic. The average tissue density was significantly greater in the surgical group than in the asymptomatic group (83.3% and 78.6%, respectively, p < 0.0001). The average tonsillar descent for surgical patients was 10.8 mm compared to 9.8 mm for asymptomatic patients (p = 0.140). The point-biserial correlation coefficient was assessed, and soft tissue density was found to positively correlate with the need for surgical intervention (rpb = 0.199, p = 0.0001), whereas tonsillar herniation did not correlate with the need for surgery (rpb = 0.083, p = 0.115). Additionally, the degree of tonsillar herniation did not correlate with soft tissue density (r = 0.09), indicating that soft tissue density is an independent morphological parameter.

CONCLUSIONS

The study findings suggest that the need for surgical intervention in CMI patients is positively correlated with increasing soft tissue density within the foramen magnum, whereas the degree of tonsillar herniation did not show a correlation with the need for surgical intervention. Additionally, soft tissue density is a factor independent of the degree of tonsillar herniation. Further investigation of tissue density within the foramen magnum is needed in the hope of discovering a clinically applicable parameter that would indicate a need for surgical intervention in patients with CMI.

Timing to surgery of Chiari malformation type 1 affects complication types: An analysis of 13,812 patients

Background:

Chiari malformations (CM) are congenital defects due to hypoplasia of the posterior fossa with cerebellar herniation into the foramen magnum and upper spinal canal. Despite the vast research done on this neurological and structural syndrome, clinical features and management options have not yet conclusively evolved. Quantification of proper treatment planning, can lead to potential perioperative benefits based on diagnoses and days to procedure. This study aims to identify if early operation produces better perioperative outcomes or if there are benefits to delaying CM surgery.

Aims and Objective:

Assess outcomes for Chiari type I.

Methods:

The KID database was queried for diagnoses of Chiari Malformation from 2003-2012 by icd9 codes (348.4, 741.0, 742.0, 742.2). Included patients: had complete time to procedure (TTP) data. Patients were stratified into 7 groups by TTP: Same-day as admission (SD), 1-day delay (1D), 2-day delay (2D), 3-day delay (3D), 4-7 days delay (4-7D), 8-14 days delay (8-14D), >14 days delay (>14D). Differences in pre-operative demographics (age/BMI) and perioperative complication rates between patient cohorts were assessed using Pearson's chi-squared tests and T-tests. Surgical details, perioperative complications, length of stay (LOS), total charges, and discharge disposition was compared. Binary logistic regressions determined independent predictors of varying complications (reference: same-day).

Results:

13,812 Chiari type I patients were isolated from KID (10.12 ± 6.3, 49.2F%, .063 ± 1.3CCI). CM-1 pts were older (10.12 yrs vs 3.62 yrs) and had a higher Charlson Comorbidity Score (0.62 vs 0.53; all P < 0.05). Procedure rates: 27.8% laminectomy, 28.3% decompression, and 2.2% spinal fusion. CM-1 experienced more complications (61.2% vs 37.9%) with the most common being related to the nervous system (2.8%), anemia (2.4%), acute respiratory distress disorder (2.1%), and dysphagia (1.2%). SD was associated with the low length of stay (5.3 days vs 9.5-25.2 days, P < 0.001), total hospital charges ($70,265.44 vs $90, 945.33-$269, 193.26, P < 0.001) when compared to other TTP groups. Relative to SD, all delay groups had significantly increased odds of developing postoperative complications (1D-OR: 1.29 [1.1- 1.6] → 8-14D-OR: 4.77[3.4-6.6]; all P < 0.05), more specifically, nervous system (1D-OR: 1.8 [1.2-2.5] → 8-14D-OR: 3.3 [1.8-6.2]; all P < 0.05).Sepsis complications were associated with a delay of at least 3D(2.5[1.4-4.6]) while respiratory complications (6.2 [3.1-12.3]) and anemia (2 [1.1-3.5]) were associated with a delay of at least 8-14D (all P < 0.05).

Chiari type I malformation: role of the Chiari Severity Index and Chicago Chiari Outcome Scale

OBJECTIVE

The authors aimed to determine whether the Chiari Severity Index (CSI), and other clinical variables, can be used as a predictor of postoperative outcomes for Chiari type I malformation (CM-I) using the modified Chicago Chiari Outcome Scale (mCCOS) as the postoperative measure.

METHODS

The cohort included patients 18 years of age and younger who were treated for CM-I between 2010 and 2015 who had at least 12 months of clinical and radiographic follow-up. CSI grades were assigned using preoperative clinical and neuroimaging data. Clinical, radiographic, and operative data were obtained from medical records. Kruskal-Wallis tests and Spearman correlations were conducted to assess for differences among CSI grades. Linear and ordinal regressions were conducted to evaluate predictors of the mCCOS and its components. Statistical significance was set a priori at p < 0.05.

RESULTS

A total of 65 patients were included in the final cohort. The average age at the time of surgery and the mean mCCOS score were 9.8 ± 4.9 years and 10.4 ± 1.4, respectively. There were no significant differences in the mean mCCOS scores or CSI grades. Pre- and postoperative syrinx sizes were similar across the total patient cohort with median sizes of 7.4 and 3.7 mm, respectively. After controlling for age at the time of surgery, whether duraplasty and/or arachnoid dissection was performed, CSI preoperative score did not predict postoperative mCCOS score. No clinical variable could predict total mCCOS score. When the mCCOS was broken down into 3 subcomponents (pain, non-pain, and complications), only one relationship was identified. Those patients who presented with no headache had a statistically significant decrease in their pain (neck pain, shoulder pain, or dysesthesia in the upper extremities) as measured by the pain component of the mCCOS (χ2 [2, n = 20] = 6.43, p = 0.04). All other preclinical predictors, including CSI grades, were nonsignificant in demonstrating correlations to the mCCOS subcomponents.

CONCLUSIONS

CSI grade was not found to be a marker of surgical outcome as measured by the mCCOS in this study. There were no correlations between the clinical variables and covariates investigated with the mCCOS. The lack of variation in mCCOS scores across this cohort may suggest that the mCCOS is not adequate for detecting differences in postsurgical outcomes. Further investigation is warranted to make this determination.

Family History in Chiari Malformation Type I: Presentation and Outcome

BACKGROUND

Some patients with Chiari malformation type I (CM-1) present with a positive family history of CM-1, the significance of which remains unknown. We aimed to study whether family history affects the clinical presentation characteristics and surgical outcome of adult patients with CM-1.

METHODS

A database of adult patients with CM-1 presenting between January 1, 2006 and December 31, 2018 was used. Presenting characteristics were compared between patients with and without a family history (first, second, or third degree) of CM-1. Among surgically treated patients, perioperative and long-term outcomes, with favorable outcome defined as a Chiari Outcome Scale score ≥14, were compared between patients with and without CM-1 family history. All patients completed at least 6 months of postoperative follow-up.

RESULTS

The database consisted of 233 adult patients with CM-1, 14 of whom (6%) had a positive family history. Presenting characteristics were comparable between patients with and without a positive family history. A total of 150 patients underwent suboccipital decompression, 12 of whom (8%) had a positive family history. After a mean follow-up of 1.9 years, patients with a family history of CM-1 were significantly less likely to achieve a favorable outcome (odds ratio, 0.22; 95% confidence interval, 0.06-0.78; P = 0.019) while controlling for several covariates. Post hoc analysis showed that the difference was most significant when looking at pain symptoms.

CONCLUSIONS

Presentation characteristics are comparable between patients with and without a family history of CM-1. Patients with a positive family history may be less likely to respond favorably to suboccipital decompression.

Obex position is associated with syringomyelia and use of posterior fossa decompression among patients with Chiari I malformation

OBJECTIVE

Chiari I malformation (CM-I) has traditionally been defined by measuring the position of the cerebellar tonsils relative to the foramen magnum. The relationships of tonsillar position to clinical presentation, syringomyelia, scoliosis, and the use of posterior fossa decompression (PFD) surgery have been studied extensively and yielded inconsistent results. Obex position has been proposed as a useful adjunctive descriptor for CM-I and may be associated with clinical disease severity.

METHODS

A retrospective chart review was performed of 442 CM-I patients with MRI who presented for clinical evaluation between 2003 and 2018. Clinical and radiological variables were measured for all patients, including presence/location of headaches, Chiari Severity Index (CSI) grade, tonsil position, obex position, clival canal angle, pB-C2 distance, occipitalization of the atlas, basilar invagination, syringomyelia, syrinx diameter, scoliosis, and use of PFD. Radiological measurements were then used to predict clinical characteristics using regression and survival analyses, with performing PFD, the presence of a syrinx, and scoliosis as outcome variables.

RESULTS

Among the radiological measurements, tonsil position, obex position, and syringomyelia were each independently associated with use of PFD. Together, obex position, tonsil position, and syringomyelia (area under the curve [AUC] 89%) or obex position and tonsil position (AUC 85.4%) were more strongly associated with use of PFD than tonsil position alone (AUC 76%) (Pdiff = 3.4 × 10-6 and 6 × 10-4, respectively) but were only slightly more associated than obex position alone (AUC 82%) (Pdiff = 0.01 and 0.18, respectively). Additionally, obex position was significantly associated with occipital headaches, CSI grade, syringomyelia, and scoliosis, independent of tonsil position. Tonsil position was associated with each of these traits when analyzed alone but did not remain significantly associated with use of PFD when included in multivariate analyses with obex position.

CONCLUSIONS

Compared with tonsil position alone, obex position is more strongly associated with symptomatic CM-I, as measured by presence of a syrinx, scoliosis, or use of PFD surgery. These results support the role of obex position as a useful radiological measurement to inform the evaluation and potentially the management of CM-I.

The SHORE Score: A Novel Predictive Tool for Improvement After Decompression Surgery in Adult Chiari Malformation Type I

BACKGROUND

A practical scoring system predicting significant improvement after surgical decompression in adult Chiari malformation type I (CM-1) based on validated outcome measures is lacking. We aimed to develop a simple score and improvement calculator to facilitate the decision making process in symptomatic CM-1 patients.

METHODS

We evaluated adult CM-1 patients who presented to our institution between September 2006 and September 2018 and underwent surgical decompression. Previously treated patients were excluded. Univariable analysis and multivariable logistic regression were conducted to derive an optimal model predictive of improvement on last follow-up as measured by the Chicago Chiari Outcome Scale. A score was derived using the beta coefficients of the model, and predictive performance was assessed using receiver operating curves with bootstrap validation. Finally, a web-based improvement calculator was deployed.

RESULTS

The surgical cohort consisted of 149 adult CM-1 patients, of which 100 (67%) experienced significant clinical improvement (Chicago Chiari Outcome Scale ≥14) after a mean follow-up of 1.9 years. The final model predictive of significant clinical improvement consisted of headache with Valsalva (odds ratio [OR] = 2.39; P = 0.030), nonwhite race (OR = 2.57; P = 0.041), absence of visual symptoms (OR = 2.59; P = 0.015), syrinx absence (OR = 1.59; P = 0.315), and increased odontoid retroflexion (OR = 2.82; P = 0.009). The score was termed SHORE, which summarizes the model's predictive factors, each assigned 1 point. The model had an area under the curve of 0.754 with an optimism-correct value of 0.721. A calculator was deployed under: https://jhuspine2.shinyapps.io/SHORE_score/.

CONCLUSIONS

The score and calculator can serve as supplements to clinical decision making by providing realistic and personalized expectations of postoperative outcome.

Risk Factors Portending Extended Length of Stay After Suboccipital Decompression for Adult Chiari I Malformation

OBJECTIVE

For adult patients undergoing surgical decompression for Chiari malformation type I (CM-I), the patient-level factors that influence extended length of stay (LOS) are relatively unknown. The aim of this study was to investigate the impact of patient-baseline comorbidities, demographics, and postoperative complications on extended LOS after intervention after adult CM-I decompression surgery.

METHODS

A retrospective cohort study using the National Inpatient Sample years 2010-2014 was performed. Adults (≥18 years) with a primary diagnosis of CM-I undergoing surgical decompression were identified. Weighted patient demographics, comorbidities, complications, LOS, disposition, and total cost were recorded. A multivariate logistic regression was used to determine the odds ratio for risk-adjusted LOS.

RESULTS

A total of 29,961 patients were identified, 6802 of whom (22.7%) had extended LOS. The extended LOS cohort had a significantly greater overall complication rate (normal LOS, 10.6% vs. extended LOS, 29.1%; P < 0.001) and total cost (normal LOS, $14,959 ± $6037 vs. extended LOS, $25,324 ± $21,629; P < 0.001) compared with the normal LOS cohort. On multivariate logistic regression, black race, income quartiles, private insurance, obstructive hydrocephalus, lack of coordination, fluid and electrolyte disorders, and paralysis were all independently associated with extended LOS. Additional duraplasty (P = 0.132) was not significantly associated with extended LOS after adjusting for other variables. The odds ratio for extended LOS was 2.07 (95% confidence interval, 1.59-2.71) for patients with 1 complication and 9.47 (95% confidence interval, 5.86-15.30) for patients with >1 complication.

CONCLUSIONS

Our study shows that extended LOS after adult CM-I decompression surgery may be influenced by multiple patient-level factors.

Systematic review and meta-analysis of imaging characteristics in Chiari I malformation: does anything really matter?

PURPOSE

Previous studies have attempted to evaluate the utility of preoperative magnetic resonance imaging (MRI) parameters in predicting outcomes in Chiari I malformation. We performed a systematic review and meta-analysis to determine what preoperative imaging features (if any) predict (1) presence of preoperative symptoms or associated findings, (2) need for surgical decompression, or (3) improvement after surgical decompression.

METHODS

All publications through June 2018 on PubMed, Embase, and Cochrane Library databases were searched using the keywords "Chiari I malformation" AND "decompression" OR "imaging." One thousand two hundred ten publications were identified, and 20 were included for our systematic review; nine were included in the meta-analysis.

RESULTS

Tonsil position, clivus gradient, and scoliotic curve of > 20° were all associated with the presence of preoperative syrinx. Degree of scoliotic curve was associated with length of syrinx. Pre-operative findings of central syrinx morphology, shorter syrinx, and scoliotic curve < 20° were associated with post-operative stability/improvement. Post-operative symptomatic improvement was associated with preoperative pB-C2 line ≥ 3 mm, absence of scoliosis, and presence of syrinx. By meta-analysis, there was no significant difference in post-operative improvement between patients with and without syrinx (OR = 0.89; 95% CI 0.58-1.37). Meta-analysis showed no significant difference in post-operative improvement between patients with and without basilar invagination (OR = 1.31; 95% CI 0.72-2.36).

CONCLUSIONS

Multiple studies have attempted to identify preoperative imaging parameters to predict post-operative improvement, but no consistently reliable criteria have been defined. This review and meta-analysis highlight the importance of considering each patient's clinical history and physical exam within the context of associated radiographic abnormalities.

PedsQL for prediction of postoperative patient-reported outcomes following Chiari decompression surgery

OBJECTIVE

The purpose of this study is to determine if the preoperative Pediatric Quality of Life Inventory (PedsQL) score is predictive of short- and intermediate-term PedsQL outcomes following Chiari decompression surgery. The utility of preoperative patient-reported outcomes (PROs) in predicting pain, opioid consumption, and long-term PROs has been demonstrated in adult spine surgery. To the best of the authors' knowledge, however, there is currently no widely accepted tool to predict short-, intermediate-, or long-term outcomes after pediatric Chiari decompression surgery.

METHODS

A prospectively maintained database was retrospectively reviewed. Patients who had undergone first-time decompression for symptomatic Chiari malformation were identified and grouped according to their preoperative PedsQL scores: mild disability (score 80-100), moderate disability (score 60-79), and severe disability (score < 60). PedsQL scores at the 6-week, 3-month, and/or 6-month follow-ups were collected. Preoperative PedsQL subgroups were tested for an association with demographic and perioperative characteristics using one-way ANOVA or chi-square analysis. Preoperative PedsQL subgroups were tested for an association with improvements in short- and intermediate-term PedsQL scores using one-way ANOVA and a paired Wilcoxon signed-rank test controlling for statistically different demographic characteristics when appropriate.

RESULTS

A total of 87 patients were included in this analysis. According to their preoperative PedsQL scores, 28% of patients had mild disability, 40% had moderate disability, and 32% had severe disability. There was a significant difference in the prevalence of comorbidities (p = 0.009) and the presenting symptoms of headaches (p = 0.032) and myelopathy (p = 0.047) among the subgroups; however, in terms of other demographic or operative factors, there was no significant difference. Patients with greater preoperative disability demonstrated statistically significantly lower PedsQL scores at all postoperative time points, except in terms of the parent-reported PedsQL at 6 months after surgery (p = 0.195). Patients with severe disability demonstrated statistically significantly greater improvements (compared to preoperative scores) in PedsQL scores at all time points after surgery, except in terms of the 6-week and 6-month PROs and the 6-month parent-reported outcomes (p = 0.068, 0.483, and 0.076, respectively).

CONCLUSIONS

Patients with severe disability, as assessed by the PedsQL, had lower absolute PedsQL scores at all time points after surgery but greater improvement in short- and intermediate-term PROs. The authors conclude that the PedsQL is an efficient and accurate tool that can quickly assess patient disability in the preoperative period and predict both short- and intermediate-term surgical outcomes.

The Seow Operative Score (SOS) as a decision-making adjunct for paediatric Chiari I malformation: a preliminary study

PURPOSE

The natural history of Chiari I malformation (C1M) in the paediatric population is poorly understood. There are conflicting reports with regards to surgical indications, operative techniques and peri-operative prognostic indicators. In this paper, we report our institutional experience in the management of paediatric C1M.

METHODS

The workflow process which includes preferred imaging modalities, surgical techniques and indications for intervention is discussed. In particular, we describe one of our current projects-an in-house designed Seow Operative Score (SOS) as a feasibility scoring system for neurosurgical intervention in our local cohort of paediatric C1M patients.

RESULTS

In our series, we have 2 groups: 10 non-operated patients versus 19 operated patients. In the non-operated group, the majority of patients had a SOS of 0 to 1. One patient had a score of 2.5 and was kept under close surveillance. Follow-up imaging demonstrated resolution of the cerebellar herniation and intraspinal syrinx. In the operated group, 17 patients had a SOS of 3 or more. Two patients had a SOS of 2. For these 2, 1 developed progressive symptoms, and the other had an extensive cervico-thoracic syrinx. Decision was made for surgery after a period of surveillance.

CONCLUSIONS

In this paper, we report our institutional experience in managing paediatric C1M and, at the same time, highlight salient points of our practices. Meanwhile, we advocate collective global efforts and in-depth research for better disease understanding of this challenging condition.

Predictive value of posterior cranial fossa morphology in the decompression of Chiari malformation type I: A retrospective observational study

Posterior fossa decompression (PFD) is the standard procedure for the treatment of Chiari malformation type I (CMI). Although most patients have satisfactory surgical outcomes, some show no improvement or even a worsening of symptoms. Patient selection is thought to account for these different surgical outcomes. Our aim was to evaluate the predictive value of the preoperative posterior cranial fossa (PCF) morphology on the efficacy of PFD.Data from 39 CMI patients with CMI-related symptoms who underwent occipital foramen enlargement + C-1 laminectomy + enlarged duraplasty were retrospectively collected from January 2011 to May 2018. The patients were divided into improved and unimproved groups according to the modified Chicago Chiari Outcome Scale. Demographic information and clinical history, including preoperative comorbidities and clinical manifestations, were recorded for the 2 groups and compared. PCF morphology was assessed based on 13 linear, 8 angular, 4 areal parameters and 4 ratios related to these liner and areal parameters. The data were then analyzed statistically.Of the 39 patients with CMI, 24 showed improvement after PFD (61.5%), whereas the remaining 15 patients showed no improvement (38.5%). The preoperative symptoms lasted 1 to 240 months, with a median of 24 months. The follow-up period ranged from 2 to 82 months, with a median of 27 months. The improved and unimproved groups differed significantly with regard to upper limb numbness (OR = 10, P = .02) and upper limb weakness (OR = 4.86, P = .02). The 2 groups did not differ significantly with regard to any morphological parameters such as tonsillar descent, syrinx size.Preoperative upper limb numbness and upper limb weakness are unfavorable factors that influence the outcome of PFD in patients with CMI. However, the morphology of PCF cannot predict the response to PFD in patients with CMI.

A Report of 2 Cases of Brainstem Hemorrhage After Suboccipital Craniectomy for Chiari Decompression

BACKGROUND AND IMPORTANCE

Decompression surgery for Chiari malformation is known to have very low procedure-related complications. There has been no report of post-Chiari malformation decompression surgery development of brainstem hemorrhage. We report 2 post-Chiari decompression surgery brainstem hemorrhage cases with 2-yr follow-up.

CLINICAL PRESENTATION

Two cases were reviewed in which patients underwent uncomplicated suboccipital craniectomy with expansive autologous pericranium duraplasty for Chiari decompression. Postoperatively, both patients awoke with hemibody sensory and motor deficits. Immediate postoperative magnetic resonance imaging revealed a small hemorrhage within the dorsal medulla in both cases. Follow-up imaging shows resolution along with near complete clinical recovery of deficits.

CONCLUSION

These cases demonstrate a rare postdecompression surgery-related complication in Chiari malformation. We hypothesize that these hemorrhages may occur from the rapid drainage of cerebrospinal fluid resulting in a loss of positive pressure, allowing a low-pressure hemorrhage to occur. Given that these hemorrhages are of low pressure, recovery is excellent.

A points-based algorithm for prognosticating clinical outcome of Chiari malformation Type I with syringomyelia: results from a predictive model analysis of 82 surgically managed adult patients

OBJECTIVE Although various predictors of postoperative outcome have been previously identified in patients with Chiari malformation Type I (CMI) with syringomyelia, there is no known algorithm for predicting a multifactorial outcome measure in this widely studied disorder. Using one of the largest preoperative variable arrays used so far in CMI research, the authors attempted to generate a formula for predicting postoperative outcome. METHODS Data from the clinical records of 82 symptomatic adult patients with CMI and altered hindbrain CSF flow who were managed with foramen magnum decompression, C-1 laminectomy, and duraplasty over an 8-year period were collected and analyzed. Various preoperative clinical and radiological variables in the 57 patients who formed the study cohort were assessed in a bivariate analysis to determine their ability to predict clinical outcome (as measured on the Chicago Chiari Outcome Scale [CCOS]) and the resolution of syrinx at the last follow-up. The variables that were significant in the bivariate analysis were further analyzed in a multiple linear regression analysis. Different regression models were tested, and the model with the best prediction of CCOS was identified and internally validated in a subcohort of 25 patients. RESULTS There was no correlation between CCOS score and syrinx resolution (p = 0.24) at a mean ± SD follow-up of 40.29 ± 10.36 months. Multiple linear regression analysis revealed that the presence of gait instability, obex position, and the M-line-fourth ventricle vertex (FVV) distance correlated with CCOS score, while the presence of motor deficits was associated with poor syrinx resolution (p ≤ 0.05). The algorithm generated from the regression model demonstrated good diagnostic accuracy (area under curve 0.81), with a score of more than 128 points demonstrating 100% specificity for clinical improvement (CCOS score of 11 or greater). The model had excellent reliability (κ = 0.85) and was validated with fair accuracy in the validation cohort (area under the curve 0.75). CONCLUSIONS The presence of gait imbalance and motor deficits independently predict worse clinical and radiological outcomes, respectively, after decompressive surgery for CMI with altered hindbrain CSF flow. Caudal displacement of the obex and a shorter M-line-FVV distance correlated with good CCOS scores, indicating that patients with a greater degree of hindbrain pathology respond better to surgery. The proposed points-based algorithm has good predictive value for postoperative multifactorial outcome in these patients.

Predictive Factors of Headache Resolution After Chiari Type 1 Malformation Surgery

BACKGROUND

Headache is the main and often isolated symptom of patients with Chiari type 1 malformation (CM1). Classically described as occipital and exacerbated by cough, headaches may be poorly characterized, making it difficult to establish CM1 as the underlying cause. Current guidelines for surgical posterior fossa decompression are undefined. The challenge is to distinguish headaches related to CM1 from headaches coincidentally coexisting with CM1. We aimed to determine predictive factors of headache resolution after surgery and applied to our cohort the Chiari Severity Index, a recently developed predictive prognostic score.

METHODS

This retrospective study enrolled 49 patients with CM1 and preoperative headache. Standardized telephone interviews regarding headaches before and after surgery were conducted by the same neurologist; magnetic resonance imaging morphometric analyses were performed by an independent neuroradiologist. Headache resolution was defined as ≥50% reduction in frequency of headache days.

RESULTS

Preoperative factors of headache resolution after multivariate analysis were attack duration <5 minutes (P = 0.001), triggering by Valsalva maneuvers (P = 0.003), severe intensity of attack (P = 0.05), occipital location (P = 0.05), and greater number of headache days per month (P = 0.04). These characteristics are part of International Headache Society diagnostic criteria for headache attributed to CM1. No radiologic predictive factor was demonstrated. Postoperative improvement was inversely correlated with Chiari Severity Index.

CONCLUSIONS

This study confirms the relevance of International Headache Society criteria to identify headaches related to CM1. We propose their systematic use in a preoperative questionnaire.

Health-related quality of life in pediatric Chiari Type I malformation: the Chiari Health Index for Pediatrics

OBJECT The purpose of this study was to design and validate a patient-reported health-related quality of life (HRQOL) instrument for pediatric Chiari Type I malformation (CM-I), the Chiari Health Index for Pediatrics (CHIP). METHODS The CHIP has 45 items with 4 components making up 2 domain scores, physical (pain frequency, pain severity, nonpain symptoms) and psychosocial; physical and psychosocial scores are combined to create an overall HRQOL score. Increasing scores (0 to 1) represent increasing HRQOL. Fifty-five patients with CM-I (mean age 12 ± 4 years, 53% male) were enrolled and completed the CHIP and Health Utilities Index Mark 3 (HUI3). Twenty-five healthy controls (mean age 11.9 ± 4 years, 40% male) also completed the CHIP. CHIP scores were compared between these groups via the Mann-Whitney U-test. For CHIP discriminative function, subscore versus presence of CM-I was compared via receiver operating characteristic curve analysis. CHIP scores in the CM-I group were stratified by symptomatology (asymptomatic, headaches, and paresthesias) and compared via Kruskal-Wallis test with Mann-Whitney U-test with Bonferroni correction (p < 0.0167). CHIP was compared with HUI3 (Health Utilities Index Mark 3) via univariate and multivariate linear regression. RESULTS CHIP physical and psychosocial subscores were, respectively, 24% and 18% lower in CM-I patients than in controls (p < 0.001); the overall HRQOL score was 23% lower as well (p < 0.001). The area under the curve (AUC) for CHIP physical subscore versus presence of CM-I was 0.809. CHIP physical subscore varied significantly with symptomatology (p = 0.001) and HUI3 pain-related quality of life (R(2) = 0.311, p < 0.001). The AUC for CHIP psychosocial subscore versus presence of CM-I was 0.754. CHIP psychosocial subscore varied significantly with HUI3 cognitive- (R(2) = 0.324, p < 0.001) and emotion-related (R(2) = 0.155, p = 0.003) quality of life. The AUC for CHIP HRQOL versus presence of CM-I was 0.820. Overall CHIP HRQOL score varied significantly with symptomatology (p = 0.001) and HUI3 multiattribute composite HRQOL score (R(2) = 0.440, p < 0.001). CONCLUSIONS The CHIP is a patient-reported, CM-I-specific HRQOL instrument, with construct validity in assessing pain-, cognitive-, and emotion-related quality of life, as well as symptomatic features unique to CM-I. It holds promise as a discriminative HRQOL index in CM-I outcomes assessment.

Chiari I Malformation in Nephropathic Cystinosis

OBJECTIVE

To determine the relative incidence of Chiari I malformations in children with cystinosis compared with those in the general population.

STUDY DESIGN

Magnetic resonance imaging scans were performed on 53 patients with nephropathic cystinosis and 120 controls, age range 3-18 years.

RESULTS

Ten of 53 (18.9%) patients with cystinosis had Chiari I or tonsillar ectopia, and only 2 of 120 controls (1.6%) had a similar finding. At least 2 of the patients had symptoms or signs thought to be related to the malformation, and one had surgical decompression. Two had an associated cervical syrinx.

CONCLUSIONS

Children with cystinosis have a 12-fold higher prevalence of Chiari I malformations than the general pediatric population. Chiari I malformations should be high on the differential diagnosis when individuals with cystinosis develop neurologic signs and symptoms, and magnetic resonance imaging scans should be performed on children with cystinosis who present with new-onset headache, ataxia, incontinence, or other unexplained neurologic symptoms.

The Chiari Severity Index: a preoperative grading system for Chiari malformation type 1

BACKGROUND

To develop evidence-based treatment guidelines for Chiari malformation type 1 (CM-1), preoperative prognostic indices capable of stratifying patients for comparative trials are needed.

OBJECTIVE

To develop a preoperative Chiari Severity Index (CSI) integrating the clinical and neuroimaging features most predictive of long-term patient-defined improvement in quality of life (QOL) after CM-1 surgery.

METHODS

We recorded preoperative clinical (eg, headaches, myelopathic symptoms) and neuroimaging (eg, syrinx size, tonsillar descent) characteristics. Brief follow-up surveys were administered to assess overall patient-defined improvement in QOL. We used sequential sequestration to develop clinical and neuroimaging grading systems and conjunctive consolidation to integrate these indices to form the CSI. We evaluated statistical significance using the Cochran-Armitage test and discrimination using the C statistic.

RESULTS

Our sample included 158 patients. Sequential sequestration identified headache characteristics and myelopathic symptoms as the most impactful clinical parameters, producing a clinical grading system with improvement rates ranging from 81% (grade 1) to 58% (grade 3) (P = .01). Based on sequential sequestration, the neuroimaging grading system included only the presence (55% improvement) or absence (74% improvement) of a syrinx ≥6 mm (P = .049). Integrating the clinical and neuroimaging indices, improvement rates for the CSI ranged from 83% (grade 1) to 45% (grade 3) (P = .002). The combined CSI had moderately better discrimination (c = 0.66) than the clinical (c = 0.62) or neuroimaging (c = 0.58) systems alone.

CONCLUSION

Integrating clinical and neuroimaging characteristics, the CSI is a novel tool that predicts patient-defined improvement after CM-1 surgery. The CSI may aid preoperative counseling and stratify patients in comparative effectiveness trials.