Cerebellar tonsillectomy with suboccipital decompression and duraplasty by small incision for Chiari I malformation (with syringomyelia): long term follow-up of 76 surgically treated cases.

AIM To explore the surgical effect of cerebellar tonsillectomy with suboccipital decompression and duraplasty by small surgical incision (3~4cm around the foramina magnum) on treating Chiari I Malformation (CM I) patients. MATERIAL AND METHODS A retrospective study was undertaken on 76 CM I patients treated by this surgery. The surgical efficacy on clinical symptoms and syringomyelia were overall evaluated and analyzed. RESULTS The study included 76 cases (36 men and 40 women; age range, 5-58 years; mean age at surgery, 38.8 years). Preoperative MRI confirmed 56 cases associated with syringomyelia. The follow-up period ranged from 25 to 58 months (median, 46 months). At the end of follow-up, 61 patients (80.26%) had improved, 12 patients (15.79%) were stabilized, and 3 patients (3.95%) had worsened. In MRI scan, syrinx of 55 patients (98.21%) had improved or stabilized compare with syrinx growth in only one patient (1.79%). Statistical analysis reveal the surgical effect tend to be much better in patients with short duration of preoperative symptoms (P=0.001). CONCLUSION Cerebellar tonsillectomy with suboccipital decompression and duraplasty can provide long-time cure for most CM I cases. Early diagnosis and surgery is necessary to improve the surgical effect. A 3~4cm incision around foramen magnum is enough for these operations and may be conducive to reduce postoperative complications.