A Morphometric Evaluation Together with Computed Tomography Examination of Chiari Type 1 Cases with Craniovertebral Junction Anomaly.

Aim: To compare the posterior cranial fossa (PCF) dimensions together with the measurements related to basilar invagination and platybasia of craniovertebral junction anomalies (CVJA) in CVJA (+) and CVJA (-) Chiari malformation Type 1 (CM1) patient groups with each other and with healthy control subjects.

Material And Methods: The study group was formed of 43 CM1 and 9 tonsillar ectopia (TE) patients.

Results: A decrease was determined in the PCF vertical length (clivus and supraocciput line) and PCF volume and an increase in the transverse length (McRae and Twining line) in the CM1 cases compared to the healthy control group. There was no difference between the CVJA (+) and (-) CM1 groups in respect of the vertical and transverse length and PCF volume values. An increase in the classic and modified skull base angles was observed in the CVJA (+) CM1 group compared to the CVJA (-) CM1 group. The Wackenheim clivus angle was determined to be smaller in the CVJA (+) CM1 group compared to the CVJA (-) CM1 group.

Conclusion: The PCF is flattened and smaller in CM1 cases compared to normal control subjects. In the planning of CM1 operations, the angle parameters may be more useful than the PCF and CVJA length parameters between CVJA (+) and (-) CM1 groups. The significant decrease in postoperative recovery in the CVJA (+) CM1 group compared to the CVJA (-) CM1 group supports the need for additional operations and/or a different surgical technique in the treatment of CVJA (+) CM1 patients.