Care for Chiari malformation type I: the role of socioeconomic disadvantage and race.

OBJECTIVE: There is little research on the effect of social determinants of health on Chiari malformation type I (CM-I). The authors analyzed data on all children evaluated for CM-I at a single institution to assess how socioeconomic factors and race affect the surgical treatment of this population. METHODS: Medical records of patients treated for CM-I at the authors' institution between 1992 and 2017 were reviewed. Area Deprivation Index (ADI) and Rural-Urban Commuting Area (RUCA) codes for each patient were used to measure neighborhood disadvantage. Non-Hispanic White patients were compared to non-White patients and Hispanic patients of any race (grouped together as non-White in this study) in terms of insurance status, ADI, and RUCA. Patients with initially benign CM-I, defined as not having undergone surgery within 9 months of their initial visit, were then stratified by having delayed symptom presentation or not, and compared on these same measures. RESULTS: The sample included 665 patients with CM-I: 82% non-Hispanic White and 18% non-White. The non-White patients were more likely to reside in disadvantaged (OR 3.4, p < 0.001) and urban (OR 4.66, p < 0.001) neighborhoods and to have public health insurance (OR 3.11, p < 0.001). More than one-quarter (29%) of patients underwent surgery. The non-White and non-Hispanic White patients had similar surgery rates (29.5% vs 28.9%, p = 0.895) at similar ages (8.8 vs 9.7 years, p = 0.406). There were no differences by race/ethnicity for symptoms at presentation. Surgical and nonsurgical patients had similar ADI scores (3.9 vs 4.2, p = 0.194), RUCA scores (2.1 vs 2.3, p = 0.252), and private health insurance rates (73.6% vs 74.2%, p = 0.878). A total of 153 patients underwent surgery within 9 months of their initial visit. The remaining 512 were deemed to have benign CM-I. Of these, 40 (7.8%) underwent decompression surgery for delayed symptom presentation. Patients with delayed symptom presentation were from less disadvantaged (ADI 3.2 vs 4.2; p = 0.025) and less rural (RUCA 1.8 vs 2.3; p = 0.023) areas than those who never underwent surgery. CONCLUSIONS: Although non-White patients were more likely to be socioeconomically disadvantaged, race and socioeconomic disadvantage were not associated with undergoing surgical treatment. However, among patients with benign CM-I, those undergoing decompression for delayed symptom presentation resided in more affluent and urban areas.

Imaging characteristics associated with surgery in Chiari malformation type I.

OBJECTIVE: In Chiari malformation type I (CM-I), a variety of imaging findings have been purported to be important; however, results have been inconclusive, inconsistent, or not replicated in independent studies. The purpose of this study was to report imaging characteristics for a large cohort of patients with CM-I and identify the imaging findings associated with surgical decompression. METHODS: Patients were identified using ICD-9 codes for CM-I for the period from 1996 to 2017. After review of the medical records, patients were excluded if they 1) did not have a diagnosis of CM-I, 2) were not evaluated by a neurosurgeon, or 3) did not have available preoperative MRI. Retrospective chart review was performed to collect demographic and clinical data. Imaging parameters were measured according to the Chiari I Malformation Common Data Elements. RESULTS: A total of 731 patients were included for analysis, having a mean follow-up duration of 25.5 months. The mean age at presentation was 8.5 years. The mean tonsil position was 11.4 mm below the foramen magnum, and 62.8% of patients had a pegged tonsil shape. Two hundred patients (27.4%) underwent surgery for life-dominating tussive headache, lower cranial nerve dysfunction, syrinx, and/or brainstem dysfunction. Surgical treatment was associated with a syrinx (OR 20.4, 95% CI 12.3-33.3, p < 0.0001), CM-1.5 (OR 1.797, 95% CI 1.08-2.98, p = 0.023), lower tonsil position (OR 1.130, 95% CI 1.08-1.18, p < 0.0001), and congenital fusion of cervical vertebrae (OR 5.473, 95% CI 1.08-27.8, p = 0.040). Among patients with benign CM-I, tonsil position was statistically significantly associated with future surgery. CONCLUSIONS: Comprehensive imaging characteristics for a large cohort of patients with CM-I are reported. Analysis showed that a lower tonsillar position, a syrinx, and CM-1.5 were associated with undergoing posterior fossa decompression. This study demonstrates the importance of considering imaging findings in the context of patient symptomatology.

Patients with "benign" Chiari I malformations require surgical decompression at a low rate.

OBJECTIVE: There are sparse published data on the natural history of "benign" Chiari I malformation (CM-I)-i.e., Chiari with minimal or no symptoms at presentation and no imaging evidence of syrinx, hydrocephalus, or spinal cord signal abnormality. The purpose of this study was to review a large cohort of children with benign CM-I and to determine whether these children become symptomatic and require surgical treatment. METHODS: Patients were identified from institutional outpatient records using International Classification of Diseases, 9th Revision, diagnosis codes for CM-I from 1996 to 2016. After review of the medical records, patients were excluded if they 1) did not have a diagnosis of CM-I, 2) were not evaluated by a neurosurgeon, 3) had previously undergone posterior fossa decompression, or 4) had imaging evidence of syringomyelia at their first appointment. To include only patients with benign Chiari (without syrinx or classic Chiari symptoms that could prompt immediate intervention), any patient who underwent decompression within 9 months of initial evaluation was excluded. After a detailed chart review, patients were excluded if they had classical Chiari malformation symptoms at presentation. The authors then determined what changes in the clinical picture prompted surgical treatment. Patients were excluded from the multivariate logistic regression analysis if they had missing data such as race and insurance; however, these patients were included in the overall survival analysis. RESULTS: A total of 427 patients were included for analysis with a median follow-up duration of 25.5 months (range 0.17-179.1 months) after initial evaluation. Fifteen patients had surgery at a median time of 21.0 months (range 11.3-139.3 months) after initial evaluation. The most common indications for surgery were tussive headache in 5 (33.3%), syringomyelia in 5 (33.3%), and nontussive headache in 5 (33.3%). Using the Kaplan-Meier method, rate of freedom from posterior fossa decompression was 95.8%, 94.1%, and 93.1% at 3, 5, and 10 years, respectively. CONCLUSIONS: Among a large cohort of patients with benign CM-I, progression of imaging abnormalities or symptoms that warrant surgical treatment is infrequent. Therefore, these patients should be managed conservatively. However, clinical follow-up of such individuals is justified, as there is a low, but nonzero, rate of new symptom or syringomyelia development. Future analyses will determine whether imaging or clinical features present at initial evaluation are associated with progression and future need for treatment.