P98. Complication rates following Chiari Malformation Surgical Management based on sub type and surgical variables

Abstract

<h3>BACKGROUND CONTEXT</h3> Chiari malformations (CM) are congenital or acquired hind brain anomalies with resultant cerebellar tonsillar herniation through the foramen magnum. These malformations are classified by the severity of the disorder as Types I-IV, each type presenting with associated features and anomalies. Despite significant research on Chiari malformations, clinical features and management options have not yet conclusively evolved. <h3>PURPOSE</h3> This study aims to identify different surgical variables and complication rates for CM sub-types. <h3>STUDY DESIGN/SETTING</h3> Retrospective cohort study of HCUP's KID (Kids' Inpatient Database), <h3>PATIENT SAMPLE</h3> A total of 35,073 Chiari Malformation patients in KID during the years of 2003-2012. <h3>OUTCOME MEASURES</h3> Perioperative outcomes in surgical spine patients (patients). <h3>METHODS</h3> The KID database was queried for diagnoses of operative Chiari Malformation from 2003-2012 by ICD-9 codes. Differences in preoperative demographics (age/BMI) and perioperative complication rates between patient cohorts were assessed using Pearson's chi-squared tests and T-tests when necessary. Binary logistic regression, which controlled for age and LOS was used to assess the contribution Chiari's has on complication rate. Level of significance was set to p<0.05. <h3>RESULTS</h3> There were 34,982 Chiari patients isolated from KID (3.17years ±6.4, 49.5F%). Of these, 39.4% were type I, 6.1% were type III, and 55.4% were type IV. Also, 5.6% of these Chiari patients experienced complications (CM-I=8.2%, CM-III=5.5%, CM-IV=3.7%; p=0.00). CM -I and IV primary diagnoses increased over time (Type I: 31.1% to 38.4%, Type IV: 17.3% to 20.8%; all p<0.001). Common surgeries performed for CM-I were: decompressions (28.6%), laminectomies (27.8%), and spinal fusions (2.2%: 2-3lvl=36.2%, 4-8lvl=12.3%, 9+=21.9%). CM – I patients were more likely to undergo surgical treatment than the other types (63.4% vs 28.6%, 15.1%; CM-III and CM –IV, respectively). The most prevalent comorbidities among the groups were anemia (I:2.4%, III:0.5%, IV:0.4%; p=0.00), cerebrovascular (I:7.3%, III:1.1%, IV: 1.0%; p=0.00), and pulmonary (I:11.7%, III: 4.0%, IV: 11.0%; p=0.00). CM-1 patients experienced more complications than CM-III and CM-4 (8.2%, 5.5%, 3.7%; all p<0.05). CM-III patients were most likely to be transferred out to an acute care hospital as opposed to other types (Type 3: 6.8% vs Type 1: 2.9% and Type IV: 4.1%; p=0.00). CM- IV had the longest length of stay with the mean being 9.91 days vs type I: 6.89 and Type 3: 7.49. CM-I patients had the following concurrent diagnoses: 11.9% syringomyelia/syringobulbia, 5.4% scoliosis, 2% hydrocephalus, and 2.2% tethered chord syndrome. There were12.0% of CM-III patients concurrently diagnosed with hydrocephalus, 1.2% tethered chord syndrome, and less than 1% had either scoliosis or syringomyelia/syringobulbia. Surgeries for CM- I, and IV increased from 2009-2012 (7.6% to 10.3%, p=0.00) and 2004-2012 (3.9% to 4.5%, p=0.00) while, the complication rates significantly decreased (1.5% to 1.3%, p<0.05; 0.6% to 0.5%); respectively. LOS (1.04 [1.04-1.03]; p=0.00) was significantly associated with developing complications in CM-1 patients. However, when controlling for age and LOS, CM-3 patients that underwent a laminectomy (4.9[10.5-2.28]; p=0.00) and CM-4 patients that underwent a spinal decompression (34.2[108.6-10.8]; p=0.00) were significantly associated with receiving a complication. <h3>CONCLUSIONS</h3> CM-1 patients were identified to have greater complication rates irrespective of procedure, most of which were less serious than other subtypes, type while CM-III and CM-IV were identified to be affected by receiving a more extensive decompressions and have more serious adverse complications. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.