CT-scan based anatomical study as a guidance for infra-acetabular screw placement

Area of Science:

• Orthopedic surgery
• Anatomy
• Medical imaging

Background:

• The infra-acetabular corridor presents a narrow surgical challenge for screw insertion.
• Understanding the anatomical relationship between corridor diameter and medial wall thickness is crucial.

Purpose of the Study:

• To investigate the correlation between infra-acetabular corridor diameter (IACD) and minimum medial acetabular wall thickness (MTMAW).
• To determine optimal screw placement strategies based on these anatomical measurements.

Main Methods:

• Computed tomography (CT) scans of 100 adult pelves were used for 3D reconstruction.
• Virtual screw placement determined IACD, and its relationship with MTMAW was analyzed.
• Screw placement strategies (all-in vs. in-out-in) were defined based on IACD thresholds.

Main Results:

• Males exhibited significantly wider IACD and MTMAW than females.
• A strong positive correlation was found between IACD and MTMAW (r=0.859).
• Distinct entry points and inclination angles were observed for all-in and in-out-in screw placements, varying between sexes.

Conclusions:

• Preoperative CT measurement of MTMAW can guide the choice of infra-acetabular screw (IAS) placement.
• The in-out-in technique involves an entry point slightly more posterior and lateral compared to the all-in technique.