Worsening or development of syringomyelia following Chiari I decompression

Abstract

<jats:sec> <jats:title>Object</jats:title> <jats:p>The effects of posterior fossa decompression on Chiari malformation Type I–induced syringomyelia have been well described. However, treatment of worsening syringomyelia after Chiari decompression remains enigmatic. This paper defines patient and clinical characteristics as well as treatment and postoperative radiological and clinical outcomes in patients experiencing this complication.</jats:p></jats:sec> <jats:sec> <jats:title>Methods</jats:title> <jats:p>The authors performed a retrospective review of patients at the Children's Hospital of Pittsburgh and Children's of Alabama who developed worsening syringomyelia after Chiari decompression was performed.</jats:p></jats:sec> <jats:sec> <jats:title>Results</jats:title> <jats:p>Fourteen children (age range 8 months to 15 years), 7 of whom had preoperative syringomyelia, underwent posterior fossa decompression. Aseptic meningitis (n = 3) and bacterial meningitis (n = 2) complicated 5 cases (4 of these patients were originally treated at outside hospitals). Worsening syringomyelia presented a median of 1.4 years (range 0.2–10.3 years) after the primary decompression. Ten children presented with new, recurrent, or persistent symptoms, and 4 were asymptomatic. Secondary Chiari decompression was performed in 11 of the 14 children. The other 3 children were advised to undergo secondary decompression. A structural cause for each failed primary Chiari decompression (for example, extensive scarring, suture in the obex, arachnoid web, residual posterior arch of C-1, and no duraplasty) was identified at the secondary operation. After secondary decompression, 8 patients' symptoms completely resolved, 1 patient's condition stabilized, and 2 patients remained asymptomatic. Radiologically, 10 of the 11 children had a decrease in the size of their syringes, and 1 child experienced no change (but improved clinically). The median follow-up from initial Chiari decompression was 3.1 years (range 0.8–14.1 years) and from secondary decompression, 1.3 years (range 0.3–4.5 years). No patient underwent syringopleural shunting or other nonposterior fossa treatment for syringomyelia.</jats:p></jats:sec> <jats:sec> <jats:title>Conclusions</jats:title> <jats:p>Based on the authors' experience, children with worsening syringomyelia after decompression for Chiari malformation Type I generally have a surgically remediable structural etiology, and secondary exploration and decompression should be considered.</jats:p></jats:sec>

Is atlantoaxial instability the cause of Chiari malformation? Outcome analysis of 65 patients treated by atlantoaxial fixation

“…A literature survey of CM treatment via foramen magnum decompression revealed surgical failure rates ranging from 20% to 50%. 27,34 Although the issue of instability has been occasionally associated with CM, its prime role in the pathogenesis of the disease has not been discussed or evaluated.…”

The changes of syrinx volume after posterior reduction and fixation of basilar invagination and atlantoaxial dislocation with syringomyelia

“…Although many theories have been proposed [11][12][13][14][15], the pathogenesis of syringomyelia is still unclear. It is generally accepted that syringomyelia is caused by disturbances of normal cerebrospinal fluid (CSF) flow circulation [7, 11-13, 16, 17].…”

Analysis of Clinical and Radiographic Outcomes of the Angle between Clivus and Supraocciput in Patients with Chiari's Malformation Type I Following Surgical Decompression

“…12,13 Therefore, adequate posterior fossa decompression has been widely advocated for reducing syrinx progression but persistence of syringomyelia is generally considered a treatment failure, and the highest reported incidence of persistent syringomyelia was 40%. [14][15][16] To explore the reasons for treatment failure, the present study compared the surgical efficacy of Chiari's decompression between patients with a C-OS angle above and below 96 degrees. This is the first study comparing such imaging measures to clinical and radiographic outcomes.…”