title: A Systematic Review of Chiari I Malformation: Techniques and Outcomes.
abstract: OBJECTIVE
  To elucidate the most efficacious treatments of Chiari I malformation (CIM).
  
  
  METHODS
  A literature search was performed using PubMed, CINAHL/Ovid, Cochrane library, and the Elsevier database. The key words "Chiari I malformation," "Chiari malformation type I," "surgery," and "treatment" were used for the search. Articles had to be peer reviewed and provide primary outcomes measured by clinical and radiographic outcomes after surgical treatments. Exclusion criteria included non-English-language articles, case reports, commentaries, information from textbooks and expert opinions, and articles that did not provide outcomes concerning specific surgical methods. Patients included were classified into 4 groups according the procedure: only bony decompression but not duroplasty (group I), bony decompression plus duroplasty (group II), bony decompression plus the resection of tonsils (group III), and shunt (group IV).
  
  
  RESULTS
  Eighteen studies were identified. Groups II and III had a significantly higher improvement rate (82.25%, 86.10%, P < 0.05) of outcomes with regard to clinical signs and symptoms than the other groups. Group IV showed a statistically higher rate (30.49%, P < 0.05) of aggregating clinical signs and symptoms. In patients with syringomyelia, group III showed better clinical improvement (96.08%). Group II displayed a significantly higher rate of decrease in the size of cavities (83.33%, P < 0.05). Group IV had a statistically higher rate of increase in the size of cavities (33.87%, P < 0.05).
  
  
  CONCLUSIONS
  Only bony decompression cannot achieve satisfactory outcomes. Bony decompression plus duroplasty showed the most favorable outcomes. Resection of tonsils was not recommended because of the high rate of side effects. Shunt may aggregate clinical signs and symptoms and increase the size of cavities.
authors.affiliation: Department of Neurosurgery, First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi Province, PR China.
authors.forename: Jian-Lan
authors.initials: JL
authors.lastname: Zhao
authors.affiliation: Department of Neurosurgery, First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi Province, PR China. Electronic address: limeihua2000@sina.com.
authors.forename: Mei-Hua
authors.initials: MH
authors.lastname: Li
authors.affiliation: Department of Neurosurgery, First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi Province, PR China.
authors.forename: Chun-Liang
authors.initials: CL
authors.lastname: Wang
authors.affiliation: Department of Neurosurgery, First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi Province, PR China.
authors.forename: Wei
authors.initials: W
authors.lastname: Meng
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D001139:Arnold-Chiari Malformation / Q000175:diagnosis / Q000401:mortality* / Q000601:surgery*; D002648:Child; D002675:Child, Preschool; D015897:Comorbidity; D019299:Decompression, Surgical / Q000401:mortality*; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008875:Middle Aged; D019635:Neurosurgical Procedures / Q000401:mortality*; D011183:Postoperative Complications / Q000175:diagnosis / Q000401:mortality*; D015995:Prevalence; D018570:Risk Assessment; D017678:Sex Distribution; D015996:Survival Rate; D016896:Treatment Outcome; D055815:Young Adult
keywords: Chiari I malformation; Clinical outcomes; Literature review; Surgical methods; Syringomyelia