Redefining Diagnostic Criteria for Basilar Invagination Using Linear Craniometric Parameters

Area of Science:

• Neurosurgery
• Radiology
• Orthopedics

Background:

• Basilar invagination (BI) is a complex craniovertebral junction abnormality.
• Accurate diagnosis of BI is crucial for effective management and surgical planning.
• Conventional radiological methods for BI diagnosis can be complex and time-consuming.

Purpose of the Study:

• To establish reliable diagnostic criteria for basilar invagination (BI) using specific bony landmarks.
• To evaluate the diagnostic accuracy of Klaus' index (KI) and the perpendicular distance from the odontoid process tip to the palato-internal occipital protuberance (PI) line.
• To compare the efficacy of these novel radiological parameters with existing methods for BI diagnosis.

Main Methods:

• Retrospective analysis of 49 patients surgically treated for BI between July 2020 and June 2023.
• Radiological assessment using reconstructed midsagittal CT images.
• Analysis of Klaus' index (KI) and the odontoid tip to PI line distance in BI patients and 120 controls.

Main Results:

• Patients with BI had a mean age of 34.82 years, with a male predominance (67.35%).
• The mean odontoid tip to PI line distance in BI patients was 3.39 mm (AUC 0.97), with a cut-off of 7.5 mm yielding 95.27% accuracy.
• Klaus' index (KI) in BI patients averaged 28.57 mm (AUC 1.00), with a cut-off of 33.2 mm achieving 100% diagnostic accuracy.

Conclusions:

• The perpendicular distance from the odontoid tip to the PI line (< 7.5 mm) is a highly accurate diagnostic parameter for BI.
• Klaus' index (< 33.2 mm) provides a highly accurate, 100% sensitive and specific diagnostic criterion for BI.
• These novel radiological parameters offer accurate and comparable diagnostic capabilities to conventional methods for basilar invagination.