title: Factors associated with spinal fusion after posterior fossa decompression in pediatric patients with Chiari I malformation and scoliosis.
abstract: OBJECTIVE The authors performed a study to identify clinical characteristics of pediatric patients diagnosed with Chiari I malformation and scoliosis associated with a need for spinal fusion after posterior fossa decompression when managing the scoliotic curve. METHODS The authors conducted a multicenter retrospective review of 44 patients, aged 18 years or younger, diagnosed with Chiari I malformation and scoliosis who underwent posterior fossa decompression from 2000 to 2010. The outcome of interest was the need for spinal fusion after decompression. RESULTS Overall, 18 patients (40%) underwent posterior fossa decompression alone, and 26 patients (60%) required a spinal fusion after the decompression. The mean Cobb angle at presentation and the proportion of patients with curves > 35° differed between the decompression-only and fusion cohorts (30.7° ± 11.8° vs 52.1° ± 26.3°, p = 0.002; 5 of 18 vs 17 of 26, p = 0.031). An odds ratio of 1.0625 favoring a need for fusion was established for each 1° of increase in Cobb angle (p = 0.012, OR 1.0625, 95% CI 1.0135-1.1138). Among the 14 patients older than 10 years of age with a primary Cobb angle exceeding 35°, 13 (93%) ultimately required fusion. Patients with at least 1 year of follow-up whose curves progressed more 10° after decompression were younger than those without curve progression (6.1 ± 3.0 years vs 13.7 ± 3.2 years, p = 0.001, Mann-Whitney U-test). Left apical thoracic curves constituted a higher proportion of curves in the decompression-only group (8 of 16 vs 1 of 21, p = 0.002). CONCLUSIONS The need for fusion after posterior fossa decompression reflected the curve severity at clinical presentation. Patients presenting with curves measuring > 35°, as well as those greater than 10 years of age, may be at greater risk for requiring fusion after posterior fossa decompression, while patients less than 10 years of age may require routine monitoring for curve progression. Left apical thoracic curves may have a better response to Chiari malformation decompression.
authors: Department of Neurosurgery, Tufts Medical Center and Floating Hospital for Children, Boston, Massachusetts.
authors: Charles E
authors: CE
authors: Mackel
authors: Department of Orthopedic Surgery, Children's Hospital of Philadelphia.
authors: Patrick J
authors: PJ
authors: Cahill
authors: Department of Neurosurgery, Tufts Medical Center and Floating Hospital for Children, Boston, Massachusetts.
authors: Marie
authors: M
authors: Roguski
authors: Shriners Hospitals for Children-Philadelphia, Pennsylvania.
authors: Amer F
authors: AF
authors: Samdani
authors: Department of Neurosurgery, Northwestern Medical Center, Chicago, Illinois.
authors: Patrick A
authors: PA
authors: Sugrue
authors: Department of Orthopaedic Surgery, Meijo Hospital, Nagoya, Japan.
authors: Noriaki
authors: N
authors: Kawakami
authors: Department of Orthopaedic Surgery, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio.
authors: Peter F
authors: PF
authors: Sturm
authors: Shriners Hospitals for Children-Philadelphia, Pennsylvania.
authors: Joshua M
authors: JM
authors: Pahys
authors: Institute for Spine and Scoliosis, Lawrenceville, New Jersey; and.
authors: Randal R
authors: RR
authors: Betz
authors: Department of Orthopaedic Surgery, IWK Health Center, Halifax, Nova Scotia, Canada.
authors: Ron
authors: R
authors: El-Hawary
authors: Shriners Hospitals for Children-Philadelphia, Pennsylvania.
authors: Steven W
authors: SW
authors: Hwang
mesh_terms: D000293:Adolescent; D001139:Arnold-Chiari Malformation / Q000150:complications / Q000175:diagnosis* / Q000601:surgery*; D002648:Child; D015331:Cohort Studies; D019299:Decompression, Surgical / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D012189:Retrospective Studies; D012600:Scoliosis / Q000150:complications / Q000175:diagnosis* / Q000601:surgery*; D013123:Spinal Fusion / Q000379:methods*; D016896:Treatment Outcome; D055815:Young Adult
keywords: CM-I = Chiari I malformation; Chiari I malformation; decompression; fusion; scoliosis; spine