[A comparative study of four combined methods for planning access to the anterior acetabular column for nail placement].

Objective: To investigate global optimisation of anterior acetabular column pinning channels can be achieved based on large density point cloud data.

Methods: Data were collected on the CT scans of the normal pelvis in 40 adults from January 2022 to January 2023, including 22 males and 18 females, aged 20 to 54 years old. Medical imaging data from three of the samples were selected for experimental study. In planning access for anterior acetabular column pinning, to address the issue of whether the current CAD planning methods were advanced or not, four combinations of the same point cloud acquisition channels, different directional line creation software, and the same 3D design and virtual experiment software were proposed: Mimics+Imageware+UG, Mimics+3DReshaper+UG, Mimics+ZEISS Quality Suite+UG and Mimics+Design X+UG, and directional lines created based on the centroid point set and solid point cloud of the secondary pruning model, respectively, and it applied to the planning of the left anterior column pinning channel of the three acetabular samples. The maximum internally connected cylinder without acetabular socket and pubic bone penetration was used as a safe passage for nailing of the anterior acetabular column to evaluate the advancement of each method.

Results: The fitting effect of the directional line was better than that of the unnoised solid point cloud when the central point set with obvious relevant features was selected as the sample points;and the combination of Mimics+Imageware+UG and Mimics+3DReshaper+UG could efficiently and stably obtain the desirable planning results when planning with the central point set, respectively, in the three acetabular samples 1, 2, 3. The maximum internal joint circle diameters obtained in samples 1, 2, and 3 were 10.35 mm, 9.62 mm, and 9.24 mm;and when the directional lines were based on the solid point cloud the combined methods of Mimics+ZEISS Quality Suite+UG and Mimics+Design X+UG were not applicable;whereas the Mimics+3DReshaper+UG the solid point cloud denoising planning method could stably obtain the maximum value of the safe channel for nail placement, and the maximum internal joint circle diameters obtained in acetabular samples 1, 2, and 3 are 10.66 mm, 10.96 mm, and 9.48 mm, respectively.

Conclusion: It is recommended that the nail placement channel planners use robust Mimics+Imageware+UG or Mimics+3DReshaper+UG centre point set planning method, and if there is enough time, it is recommended to use the solid point cloud denoising planning method of Mimics+3DReshaper+UG in order to obtain the maximum value of safe channels for nail placement.