Research Article

Possible Reasons for Failure and Surgical Problems in Complex Chiari Cases


  • Eyüp Bayatlı
  • Özgür Orhan
  • Eray Serhat Aktan
  • Onur Özgüral
  • İhsan Doğan
  • Melih Bozkurt
  • Hasan Çağlar Uğur
  • Yusuf Şükrü Çağlar

Received Date: 02.06.2023 Accepted Date: 22.10.2023 J Ankara Univ Fac Med 2023;76(4):354-360


Chiari malformations (CM) are common, highly variable, congenital problems of the craniovertebral junction and hindbrain. The term complex Chiari is used to describe cases that do not benefit from simple posterior fossa decompression and require occipitocervical fusion or odontoidectomy. Our series and medical literature are reviewed to discuss some cases of failed CM surgery that worsened after decompression.

Materials and Methods:

Patients diagnosed with CM and operated between 2010 and 2020 were examined. In addition, a bibliography-based research was conducted using the Medline, PubMed and Science databases. Three sample cases of unsuccessful Chiari surgery are presented at random to discuss possible misdiagnosis, clinical problems, and surgical interventions.


Detailed data of 60 patients diagnosed with CM and operated on were analyzed. The patient series consisted of 37 women (61.7%) and 23 men (38.3%). On radiological examinations, 95% of the patients had a mean cerebellar tonsil herniation of 11 mm (median 11 mm; 5-25; ±4.63). Basilar Invagination was present in 5 patients (8.33%), tethered spinal cord malformation in 1 patient (1.67%), spina bifida in 1 patient (1.67%), and spinal arachnoid cyst in 1 patient (1.67%).


For successful surgical treatment of CM, preoperative radiological evaluation and determining the relationship between findings and clinical symptoms are as important as surgical treatment itself.

Keywords: Chiari Malformations, Complex Chiari, Craniovertebral Junction, Failed Chiari, Occipitocervical Fusion

Full Text (Turkish)