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OBJECTIVE The goal of this study was to assess the social determinants that influence access and outcomes for pediatric neurosurgical care for patients with Chiari malformation type I (CM-I) and syringomyelia (SM). METHODS The authors used retro- and prospective components of the Park-Reeves Syringomyelia Research Consortium database to identify pediatric patients with CM-I and SM who received surgical treatment and had at least 1 year of follow-up data. Race, ethnicity, and insurance status were used as comparators for preoperative, treatment, and postoperative characteristics and outcomes. RESULTS A total of 637 patients met inclusion criteria, and race or ethnicity data were available for 603 (94.7%) patients. A total of 463 (76.8%) were non-Hispanic White (NHW) and 140 (23.2%) were non-White. The non-White patients were older at diagnosis (p = 0.002) and were more likely to have an individualized education plan (p < 0.01). More non-White than NHW patients presented with cerebellar and cranial nerve deficits (i.e., gait ataxia [p = 0.028], nystagmus [p = 0.002], dysconjugate gaze [p = 0.03], hearing loss [p = 0.003], gait instability [p = 0.003], tremor [p = 0.021], or dysmetria [p < 0.001]). Non-White patients had higher rates of skull malformation (p = 0.004), platybasia (p = 0.002), and basilar invagination (p = 0.036). Non-White patients were more likely to be treated at low-volume centers than at high-volume centers (38.7% vs 15.2%; p < 0.01). Non-White patients were older at the time of surgery (p = 0.001) and had longer operative times (p < 0.001), higher estimated blood loss (p < 0.001), and a longer hospital stay (p = 0.04). There were no major group differences in terms of treatments performed or complications. The majority of subjects used private insurance (440, 71.5%), whereas 175 (28.5%) were using Medicaid or self-pay. Private insurance was used in 42.2% of non-White patients compared to 79.8% of NHW patients (p < 0.01). There were no major differences in presentation, treatment, or outcome between insurance groups. In multivariate modeling, non-White patients were more likely to present at an older age after controlling for sex and insurance status (p < 0.01). Non-White and male patients had a longer duration of symptoms before reaching diagnosis (p = 0.033 and 0.004, respectively). CONCLUSIONS Socioeconomic and demographic factors appear to influence the presentation and management of patients with CM-I and SM. Race is associated with age and timing of diagnosis as well as operating room time, estimated blood loss, and length of hospital stay. This exploration of socioeconomic and demographic barriers to care will be useful in understanding how to improve access to pediatric neurosurgical care for patients with CM-I and SM.

INTRODUCTION: The decision regarding whether to perform an interventional procedure as a strategy to prevent hemorrhage of an unruptured intracranial aneurysm (UIA) requires careful consideration of procedural risk and the UIA natural history. No randomized trial data are available. The International Study of Unruptured Intracranial Aneurysms (ISUIA) included a prospective cohort, examining hemorrhage risk and treatment risk. Hypothesis: The purpose of this analysis was to compare the factors related to treatment selection and determination of the number of hemorrhages prevented. Methods: Patients were allocated into the initial treatment and untreated cohorts based upon observation or treatment practices in 61 centers from 1991-1998. 1691 patients were in the observational cohort, 471 were in the endovascular cohort and 1917 patients were in the surgical cohort. The cohorts were followed for a median follow-up of 9.2 years. Outcomes were determined prospectively and with central review. The data were grouped together and analyzed to determine treatment decisions. A Cox proportional hazards model predicting hemorrhage developed in the observation cohort and was applied to the surgery and endovascular cohorts across the follow-up period. Results: Significant baseline variable differences between treated and observed patients were aneurysm size, symptoms, age, prior SAH group, geographical region, treatment percentage, aneurysm daughter sacs or multiple lobes, and history of hypertension, smoking and myocardial infarction. Aneurysm site and family history were not significant. Site, size, and aspirin use were significant predictors of hemorrhage. Long-term the predicted hemorrhage rates were 6.7% at 5 years and 8.0% at 10 years in the surgery group and 8.1% and 9.6% for the endovascular group, respectively. For comparison the rates in the observed cohort were 4.1% and 4.8%, respectively. Conclusions: Decisions for treatment are influenced by patient characteristics such as age and medical history, aneurysm characteristics such as size and morphology and center and regional practices. Patients in the treated cohorts were at moderately increased risk for hemorrhage compared to those in the observed cohort.

Introduction: There is ongoing debate regarding the rupture risk of an unruptured intracranial aneurysm (UIA), and the predictors of rupture. Hypothesis: There are aneurysm morphology characteristics which predict rupture in patients with an UIA. The purpose of this analysis was to assess for such characteristics utilizing the International Study of Unruptured Intracranial Aneurysms (ISUIA) cohort. Methods: Patients were entered prospectively at 61 centers. Patients must have had at least one UIA, which may or may not have been symptomatic. Patients were followed for a median of 9 years and all potential hemorrhages were carefully adjudicated. A case-control design was used. The cases were 57 patients with aneurysmal rupture during followup for whom detailed radiology data were available from arteriography. Controls were 198 size- (+/- 2 mm maximum diameter) and location- (parent artery) matched patients without rupture during followup. Numerous aneurysm morphology characteristics were assessed on arteriogram review. Multivariable condition logistic regression modeling was performed. Results: A total of 57 cases and 198 controls were included. Most (76%) of the 255 cases were women, and 20% had a prior history of SAH from some other aneurysm. There were no differences between cases and controls in aneurysm maximum diameter, aneurysm location, patient age, gender, reason for presentation, or prior medical history. Multivariate analysis identified that only perpendicular height of the aneurysm--the measurement of the aneurysm height at a perpendicular to the center of the aneurysm neck to the aneurysm dome-was an independent predictor of aneurysm rupture. Aspect ratio, size ratio, parent vessel diameter, presence of daughter sac, and aneurysm angle were not independent predictors of rupture. Conclusions: After controlling for aneurysm size and location, the aneurysm perpendicular height remained a predictor of UIA rupture during long-term followup. The assessment of perpendicular height may be helpful in clinical practice, in addition to the other key predictors of UIA rupture, aneurysm maximum diameter and location. Further investigation into the use of perpendicular height as a predictor of rupture in patients with UIA is indicated.

Introduction: Giant intracranial aneurysms are uncommon, have a high risk for rupture and are difficult to treat. The International Study of Unruptured Intracranial Aneurysms (ISUIA) prospective cohort included 187 patients with maximal diameter of 25 mm or greater. This analysis was to determine the long-term prognosis of these aneurysms both treated and untreated. Methods: Patients were enrolled into ISUIA at 61 centers from 1991-1998. A prospective cohort included the managed with observation, surgery or endovascular treatment. Patients were followed for a median of 9.2 years. Aneurysms were measured using a central reading of bi-planar cerebral angiography. Outcomes were determined prospectively and with central review. Results: 187 patients with a maximum diameter of 25 mm were followed. The mean size was 30.3 mm, ranging from 25 to 63 mm. 39% of the aneurysms were surgically treated at baseline, 27% were endovascularly treated, and 32% were managed conservatively;3% had subsequent endovascular treatment and 5% surgical treatment. Patients with giant aneurysms were predominantly women (83%), had a baseline Rankin Score of in 93%, were located predominantly in the anterior circulation (internal carotid 44%, cavernous ICA 28%, middle cerebral 12%). 80% of the patients were symptomatic with cranial nerve deficit in 47% (III and VI nerves), mass effect in 16%, headaches in 44%, orbital pain in 21%, and vision loss in 25%. Smoking history was present in 67%, hypertension in 44%, vascular headaches in 29% and family history in 10%. 70 patients (39%) died during follow-up however 59% were still Rankin 1 or 2. Both surgical and endovascular treated patients had 60-64% good outcome and 34-36% mortality. Untreated patients had a 57% mortality. Subarachnoid hemorrhage occurred in 11 untreated patients and 12 treated patients with most occurring in the first year. Conclusions: Giant intracranial aneurysms are typically symptomatic, and have a high risk of rupture early after diagnosis. Outcome was similar with surgical and endovascular treatment but post-procedure hemorrhage did occur.

OBJECTIVE Posterior fossa decompression with duraplasty (PFDD) is commonly performed for Chiari I malformation (CM-I) with syringomyelia (SM). However, complication rates associated with various dural graft types are not well established. The objective of this study was to elucidate complication rates within 6 months of surgery among autograft and commonly used nonautologous grafts for pediatric patients who underwent PFDD for CM-I/SM. METHODS The Park-Reeves Syringomyelia Research Consortium database was queried for pediatric patients who had undergone PFDD for CM-I with SM. All patients had tonsillar ectopia ≥ 5 mm, syrinx diameter ≥ 3 mm, and ≥ 6 months of postoperative follow-up after PFDD. Complications (e.g., pseudomeningocele, CSF leak, meningitis, and hydrocephalus) and postoperative changes in syrinx size, headaches, and neck pain were compared for autograft versus nonautologous graft. RESULTS A total of 781 PFDD cases were analyzed (359 autograft, 422 nonautologous graft). Nonautologous grafts included bovine pericardium (n = 63), bovine collagen (n = 225), synthetic (n = 99), and human cadaveric allograft (n = 35). Autograft (103/359, 28.7%) had a similar overall complication rate compared to nonautologous graft (143/422, 33.9%) (p = 0.12). However, nonautologous graft was associated with significantly higher rates of pseudomeningocele (p = 0.04) and meningitis (p < 0.001). The higher rate of meningitis was influenced particularly by the higher rate of chemical meningitis (p = 0.002) versus infectious meningitis (p = 0.132). Among 4 types of nonautologous grafts, there were differences in complication rates (p = 0.02), including chemical meningitis (p = 0.01) and postoperative nausea/vomiting (p = 0.03). Allograft demonstrated the lowest complication rates overall (14.3%) and yielded significantly fewer complications compared to bovine collagen (p = 0.02) and synthetic (p = 0.003) grafts. Synthetic graft yielded higher complication rates than autograft (p = 0.01). Autograft and nonautologous graft resulted in equal improvements in syrinx size (p < 0.0001). No differences were found for postoperative changes in headaches or neck pain. CONCLUSIONS In the largest multicenter cohort to date, complication rates for dural autograft and nonautologous graft are similar after PFDD for CM-I/SM, although nonautologous graft results in higher rates of pseudomeningocele and meningitis. Rates of meningitis differ among nonautologous graft types. Autograft and nonautologous graft are equivalent for reducing syrinx size, headaches, and neck pain.

Abstract BACKGROUND Occipital-cervical fusion (OCF) and ventral decompression (VD) may be used in the treatment of pediatric Chiari-1 malformation (CM-1) with syringomyelia (SM) as adjuncts to posterior fossa decompression (PFD) for complex craniovertebral junction pathology. OBJECTIVE To examine factors influencing the use of OCF and OCF/VD in a multicenter cohort of pediatric CM-1 and SM subjects treated with PFD. METHODS The Park-Reeves Syringomyelia Research Consortium registry was used to examine 637 subjects with cerebellar tonsillar ectopia ≥ 5 mm, syrinx diameter ≥ 3 mm, and at least 1 yr of follow-up after their index PFD. Comparisons were made between subjects who received PFD alone and those with PFD + OCF or PFD + OCF/VD. RESULTS All 637 patients underwent PFD, 505 (79.2%) with and 132 (20.8%) without duraplasty. A total of 12 subjects went on to have OCF at some point in their management (PFD + OCF), whereas 4 had OCF and VD (PFD + OCF/VD). Of those with complete data, a history of platybasia (3/10, P = .011), Klippel-Feil (2/10, P = .015), and basilar invagination (3/12, P < .001) were increased within the OCF group, whereas only basilar invagination (1/4, P < .001) was increased in the OCF/VD group. Clivo-axial angle (CXA) was significantly lower for both OCF (128.8 ± 15.3°, P = .008) and OCF/VD (115.0 ± 11.6°, P = .025) groups when compared to PFD-only group (145.3 ± 12.7°). pB-C2 did not differ among groups. CONCLUSION Although PFD alone is adequate for treating the vast majority of CM-1/SM patients, OCF or OCF/VD may be occasionally utilized. Cranial base and spine pathologies and CXA may provide insight into the need for OCF and/or OCF/VD.

OBJECTIVEScoliosis is frequently a presenting sign of Chiari malformation type I (CM-I) with syrinx. The authors’ goal was to define scoliosis in this population and describe how radiological characteristics of CM-I and syrinx relate to the presence and severity of scoliosis.METHODSA large multicenter retrospective and prospective registry of pediatric patients with CM-I (tonsils ≥ 5 mm below the foramen magnum) and syrinx (≥ 3 mm in axial width) was reviewed for clinical and radiological characteristics of CM-I, syrinx, and scoliosis (coronal curve ≥ 10°).RESULTSBased on available imaging of patients with CM-I and syrinx, 260 of 825 patients (31%) had a clear diagnosis of scoliosis based on radiographs or coronal MRI. Forty-nine patients (5.9%) did not have scoliosis, and in 516 (63%) patients, a clear determination of the presence or absence of scoliosis could not be made. Comparison of patients with and those without a definite scoliosis diagnosis indicated that scoliosis was associated with wider syrinxes (8.7 vs 6.3 mm, OR 1.25, p < 0.001), longer syrinxes (10.3 vs 6.2 levels, OR 1.18, p < 0.001), syrinxes with their rostral extent located in the cervical spine (94% vs 80%, OR 3.91, p = 0.001), and holocord syrinxes (50% vs 16%, OR 5.61, p < 0.001). Multivariable regression analysis revealed syrinx length and the presence of holocord syrinx to be independent predictors of scoliosis in this patient cohort. Scoliosis was not associated with sex, age at CM-I diagnosis, tonsil position, pB–C2 distance (measured perpendicular distance from the ventral dura to a line drawn from the basion to the posterior-inferior aspect of C2), clivoaxial angle, or frontal-occipital horn ratio. Average curve magnitude was 29.9°, and 37.7% of patients had a left thoracic curve. Older age at CM-I or syrinx diagnosis (p < 0.0001) was associated with greater curve magnitude whereas there was no association between syrinx dimensions and curve magnitude.CONCLUSIONSSyrinx characteristics, but not tonsil position, were related to the presence of scoliosis in patients with CM-I, and there was an independent association of syrinx length and holocord syrinx with scoliosis. Further study is needed to evaluate the nature of the relationship between syrinx and scoliosis in patients with CM-I.

Objective: Aneurysm growth is considered predictive of future rupture of intracranial aneurysms. However, it is still unknown how accurately neuroradiologists can reliably detect incremental aneurysm growth using clinical magnetic resonance imaging (MRI) imaging. The purpose of this study is to assess the agreement rate of detecting aneurysm enlargement using generally used MRI imaging modalities. Methods: Three silicone flow phantom models each with eight aneurysms of various sizes in different sites were used in this study. The aneurysm models were identical except for an incremental increase in size of the 8 aneurysms ranging from 0.4mm to 2mm. The phantoms were imaged on 1.5 tesla (T) and 3T MRI units with both time-of-flight (TOF) and contrast enhanced magnetic resonance angiography (MRA). Three independent expert neuroradiologists measured the aneurysms in a blinded fashion utilizing different measurement approaches. The individual and agreement rate among the three experts in detecting aneurysm enlargement were calculated. Results: The average detection rate of any increase in any aneurysmal dimensions was 95.7%. The detection rate for the three readers (A, B and C) was 98.0%, 96.6% and 92.7%, respectively ( P =0.22). The detection rate in each MRI modality was 91.3% using 1.5 T TOF, 97.2% using 1.5T gadolinium (Gad), 95.8% using 3.0T TOF and 97.2% using 3.0T Gad ( P =0.31). As the incremental enlargement value increased, the detection rate for aneurysm enlargement increased. Use of Gad in 1.5T improved the detection rate in small incremental enlargement (e.g. 0.4 - 1mm) of the aneurysm ( P =0.04). The locations of the aneurysms also affected detection rate for aneurysm enlargement ( P <0.0001). Conclusions: The detection rate and interobserver agreement was very high for aneurysm enlargement of 0.4mm to 2 mm. Detection rate of any increase in any aneurysmal dimensions did not depend on the choice of MRI imaging modalities and measurement protocols.

OBJECTIVEAneurysm growth is considered predictive of future rupture of intracranial aneurysms. However, how accurately neuroradiologists can reliably detect incremental aneurysm growth using clinical MRI is still unknown. The purpose of this study was to assess the agreement rate of detecting aneurysm enlargement employing generally used MRI modalities.METHODSThree silicone flow phantom models, each with 8 aneurysms of various sizes at different sites, were used in this study. The aneurysm models were identical except for an incremental increase in the sizes of the 8 aneurysms, which ranged from 0.4 mm to 2 mm. The phantoms were imaged on 1.5-T and 3-T MRI units with both time-of-flight (TOF) and contrast-enhanced MR angiography. Three independent expert neuroradiologists measured the aneurysms in a blinded manner using different measurement approaches. The individual and agreement detection rates of aneurysm enlargement among the 3 experts were calculated.RESULTSThe mean detection rate of any increase in any aneurysmal dimension was 95.7%. The detection rates of the 3 observers (observers A, B, and C) were 98.0%, 96.6%, and 92.7%, respectively (p = 0.22). The detection rates of each MRI modality were 91.3% using 1.5-T TOF, 97.2% using 1.5-T with Gd, 95.8% using 3.0-T TOF, and 97.2% using 3.0-T with Gd (p = 0.31). On the other hand, the mean detection rate for aneurysm enlargement was 54.8%. Specifically, the detection rates of observers A, B, and C were 49.0%, 46.1%, and 66.7%, respectively (p = 0.009). As the incremental enlargement value increased, the detection rate for aneurysm enlargement increased. The use of 1.5-T Gd improved the detection rate for small incremental enlargement (e.g., 0.4–1 mm) of the aneurysm (p = 0.04). The location of the aneurysm also affected the detection rate for aneurysm enlargement (p < 0.0001).CONCLUSIONSThe detection rate and interobserver agreement were very high for aneurysm enlargement of 0.4–2 mm. The detection rate for at least 1 increase in any aneurysm dimension did not depend on the choice of MRI modality or measurement protocol. Use of Gd improved the accuracy of measurement. Aneurysm location may influence the accuracy of detecting enlargement.

OBJECTIVEThe natural history of complete spinal cord injury (SCI) is poorly studied. The classically quoted rate of improvement or conversion for patients with American Spinal Injury Association (ASIA) grade A (ASIA A) injuries is 15%–20%; however, data supporting this rate are very limited. In this paper, the authors conducted a meta-analysis of modern data reporting on ASIA A patients and evaluated factors affecting the natural history of the disease.METHODSThe authors conducted a systematic literature review of all randomized clinical trials (RCTs) and observational studies of patients with traumatic SCI. The Embase, MEDLINE, PubMed, Scopus, CINAHL, and Cochrane databases were reviewed for all studies reporting on SCI and published after 1992. A meta-analysis was conducted using the DerSimonian and Laird (random-effects) model with a summary odds ratio analysis.RESULTSEleven RCTs and 9 observational studies were included in the final analysis. Overall, the 20 included studies reported on 1162 patients with ASIA A injuries. The overall conversion rate was 28.1%, with 327 of 1162 patients improving to at least ASIA B. The overall rate of conversion noted in cervical spine injuries was 33.3%, whereas that in thoracic injuries was 30.6%. Patients undergoing early surgery had a higher rate of conversion (46.1%) than patients undergoing late surgery (25%) (OR 2.31, 95% CI 1.08–4.96, p = 0.03).CONCLUSIONSThe overall rate of conversion of ASIA A SCIs from pooled data of prospective trials and observational series is 28.1%. This rate of conversion is higher than what is reported in the literature. Early surgery is predictive of a higher conversion rate. However, there are not enough data to provide conclusions pertaining to the efficacy of biological and medical therapies.