title: Risks and outcomes of spinal deformity surgery in Chiari malformation, Type 1, with syringomyelia versus adolescent idiopathic scoliosis.
abstract: BACKGROUND
  Chiari malformation, Type 1, with syringomyelia (CIM+SM) is often associated with spinal deformity. The safety of scoliosis surgery this population is controversial and has never been directly compared with adolescent idiopathic scoliosis (AIS).
  
  
  OBJECTIVE
  The purpose of this study was to compare the safety and subjective outcomes of spinal deformity surgery between patients with Chiari malformation Type 1-associated scoliosis and a matched AIS cohort.
  
  
  METHODS
  This study is based on a retrospective matched cohort analysis.
  
  
  METHODS
  Patients with CIM+SM and treated with spinal fusion for spinal deformity were identified in the surgical records of a single institution and were matched, 1:1, with AIS patients undergoing spinal fusion at the same institution.
  
  
  METHODS
  The outcome measures were neurological monitoring data quality and integrity, radiographic parameters, and Scoliosis Research Society Questionnaire-22 (SRS-22) scores.
  
  
  METHODS
  A clinical database was reviewed for patients undergoing spinal reconstruction for CIM+SM-associated spinal deformity at our institution from 2000 to 2012. Thirty-six CIM+SM patients were identified and matched to an AIS cohort (1:1) based on age, gender, major curve magnitude, fusion length, and revision status. Demographics, deformity morphology, surgical details, neuromonitoring data, and preoperative and postoperative SRS-22 scores were recorded at a minimum of 2-year follow-up. Changes in SRS-22 scores were compared within and between groups. Complications and neurological monitoring data issues were compared between groups.
  
  
  RESULTS
  Mean age was 14.5±5 years (CIM+SM: 14.6±5; AIS: 14.4±5), and 42% of patients were male. Preoperative mean major coronal Cobb measured 58°±25° versus 57°±17° (p=.84) with mean kyphosis 52°±17° versus 41°±20° (p=.018). An average of 10.4±2.6 vertebral levels were fused (10.4±2.8 vs. 10.4±2.3, p=.928). No differences existed in surgical approach (p=.336), estimated blood loss (680±720 vs. 660±310 mL, p=.845), or duration of surgery (6.0±2.2 vs. 5.6±2 hours, p=.434). Complication rate was comparable between the two groups (33% vs. 14%, p=.052). Chiari malformation, Type 1, with syringomyelia experienced more neurological complications (11% vs. 0%, p=.04) and neuromonitoring difficulties (28% vs. 3%, p=.007) than the AIS cohort. Mean curve correction was comparable at 2 years (58% CIM+SM vs. 64% AIS, p=.2). At follow-up, both CIM+SM and AIS groups demonstrated improved cumulative SRS-22 outcome subscores (CIM+SM: +0.4, p=.027; AIS: +0.3, p<.001). No difference in outcome subscores existed between CIM+SM and AIS groups.
  
  
  CONCLUSIONS
  Although CIM+SM patients undergoing spine reconstruction can expect similar deformity corrections and outcome scores to AIS patients, they also experience higher rates of neuromonitoring difficulties and neurological complications related to surgery. Surgeons should be prepared for these difficulties, particularly in children with larger syrinx size.
authors.affiliation: Department of Orthopaedic Surgery, Washington University School of Medicine, 660 S Euclid Ave., Campus Box 8233, St Louis, MO 63110, USA.
authors.forename: Jakub
authors.initials: J
authors.lastname: Godzik
authors.affiliation: Department of Neurological Surgery, Washington University School of Medicine, 660 S Euclid Ave., St Louis, MO, USA.
authors.forename: Terrence F
authors.initials: TF
authors.lastname: Holekamp
authors.affiliation: Department of Neurological Surgery, Washington University School of Medicine, 660 S Euclid Ave., St Louis, MO, USA.
authors.forename: David D
authors.initials: DD
authors.lastname: Limbrick
authors.affiliation: Department of Orthopaedic Surgery, Washington University School of Medicine, 660 S Euclid Ave., Campus Box 8233, St Louis, MO 63110, USA.
authors.forename: Lawrence G
authors.initials: LG
authors.lastname: Lenke
authors.affiliation: Department of Neurological Surgery, Washington University School of Medicine, 660 S Euclid Ave., St Louis, MO, USA.
authors.forename: T S
authors.initials: TS
authors.lastname: Park
authors.affiliation: Department of Neurological Surgery, Washington University School of Medicine, 660 S Euclid Ave., St Louis, MO, USA.
authors.forename: Wilson Z
authors.initials: WZ
authors.lastname: Ray
authors.affiliation: Department of Orthopaedic Surgery, Washington University School of Medicine, 660 S Euclid Ave., Campus Box 8233, St Louis, MO 63110, USA.
authors.forename: Keith H
authors.initials: KH
authors.lastname: Bridwell
authors.affiliation: Department of Orthopaedic Surgery, Washington University School of Medicine, 660 S Euclid Ave., Campus Box 8233, St Louis, MO 63110, USA. Electronic address: kellymi@wudosis.wustl.edu.
authors.forename: Michael P
authors.initials: MP
authors.lastname: Kelly
mesh_terms: D000293:Adolescent; D001139:Arnold-Chiari Malformation / Q000601:surgery*; D001863:Bone Screws / Q000009:adverse effects; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D013123:Spinal Fusion / Q000009:adverse effects* / Q000379:methods; D013595:Syringomyelia / Q000601:surgery*
keywords: Adolescent idiopathic scoliosis; Chiari malformation; Chiari-associated spinal deformity; Kyphosis; Scoliosis; Spinal deformity; Syringomyelia