[Correlation between syrinx resolution after posterior fossa decompression and cervical sagittal profile change in adolescents with Chiari malformation and syringomyelia].

Objective

To evaluate the long term change of the cervical sagittal profile in adolescent Chiari malformation type Ⅰ (CMI)/syringomyelia undergoing posterior fossa decompression (PFD) and to further evaluate the correlation between the syrinx resolution and cervical sagittal profile.

Methods

A retrospective radiographic study was performed in 32 adolescents undergoing PFD for CMI/syringomyelia from October 2011 to August 2015 with a minimum 2-year follow-up. There were 23 males and 9 females, with a mean age of (13.7±2.8) years (range, 10-16 years). The following parameters including upper cervical angle (C(0)-C(2)), lower cervical angle (C(2)-C(7)), sagittal balance (C(2)-C(7)SVA), cervical curvature index (CCI), syrinx size and length were compared preoperatively and at the last follow-up. The correlation of syrinx resolution and cervical sagittal parameters were further analyzed with Pearson correlation analysis.

Results

All patients received a followed-up for 2.0-6.5 years [mean (3.9±1.1) years]. The lower cervical angle and CCI were-29.8°±11.4° and 29.1%±7.1% at the last follow-up, respectively, which were significantly higher than those before surgery (-15.2°±8.8°, 13.4%±4.2%)(t=2.917, 2.902, both P<0.05). The syrinx size and length were also obviously decreased at the last follow-up. No significant difference was found in the upper cervical angle and C(2)-C(7)SVA before operation and at the last follow-up (t=0.302, 0.871, both P>0.05). There were significantly positive correlations between the differences of syrinx width and the lower cervical angle, and the CCI before and after surgery (r=0.611, 0.652, both P<0.05). Significantly positive correlations were also observed between the differences of syrinx length and the lower cervical angle, and the CCI before and after surgery (r=0.504, 0.514, both P<0.05).

Conclusions

The cervical lordosis can be restored after PFD in adolescents with CMI/syringomyelia. The resolution of syrinx may play an important role in restoring the cervical sagittal alignment.