The evaluation of surgical treatment options in the chiari malformation type I

Abstract

Aim: There have been several treatment modalities to reduce the volume of the syringomyelic cavity and the pressure on the brainstem in Chiari Malformation Type I (CM-I). Foramen magnum decompression with and without duroplasty were compared in this retrospective study. Material and Methods: From 2003 to 2006, 27 patients suffering from CMI were operated on at our institute. The following were measured: the ratio of the syringomyelic cavity to the spinal cord; pre-operative tonsillar herniation from the foramen magnum; pre-and postoperative tonsillo-dural distance; and spinoposterior fossa dural angle. Results: 83.3 % of the patients in the non-duroplasty and 73.3% of the patients in the duroplasty group were symptom free. The ratio of syrinx regression was 28±10% in the non-duroplasty and 36±33% in the duroplasty group. The tonsillodural distance was 3.1±1.8 mm in the non-duroplasty and 4.6±2.1 mm in the duroplasty group (p>0.05). The spino-posterior fossa dural angle was 133.6±9.44° preoperatively and 136.7 ± 9.78° postoperatively in the non-duroplasty (p=0.376); 123.7±11.7° preoperatively and 129.8±11.1° postoperatively in the duroplasty group (p=0.885); no significant difference was found postoperatively (p=0.55, z=1.92), respectively. One patient was re-operated in the non-duroplasty group and thereafter duroplasty was performed. Conclusion: Almost the same clinical outcomes can be achieved with and without duroplasty. There might be an option to perform duroplasty if simple procedure fails.