Validation of the OrthoGnathicAnalyser 2.0—3D accuracy assessment tool for bimaxillary surgery and genioplasty

Abstract

Orthognathic surgery is a widely performed procedure to correct dentofacial deformities. Virtual treatment planning is an important preparation step. One advantage of the use of virtual treatment planning is the possibility to assess the accuracy of orthognathic surgery. In this study, a tool (OrthoGnathicAnalyser 2.0), which allows for quantification of the accuracy of orthognathic surgery, is presented and validated. In the OrthoGnathicAnalyser 2.0 the accuracy of the osseous chin can now be assessed which was not possible in the earlier version of the OrthoGnathicAnalyser. 30 patients who underwent bimaxillary surgery in combination with a genioplasty were selected from three different centers in the Netherlands. A pre-operative (CB)CT scan, virtual treatment planning and postoperative (CB)CT scan were required for assessing the accuracy of bimaxillary surgery. The preoperative and postoperative (CB)CT scans were aligned using voxel-based matching. Furthermore, voxel-based matching was used to align the pre-operative maxilla, mandible and rami towards their postoperative position whereas surface-based matching was used for aligning the pre-operative chin towards the postoperative position. The alignment resulted in a transformation matrix which contained the achieved translations and rotations. The achieved translations and rotations can be compared to planning values of the virtual treatment plan. To study the reproducibility, two independent observers processed all 30 patients to assess the inter-observer variability. One observer processed the patients twice to assess the intra-observer variability. Both the intra- and inter-observer variability showed high ICC values (> 0.92) and low measurement variations (< 0.673±0.684mm and < 0.654±0.824°). The results of this study show that the OrthoGnathicAnalyser 2.0 has an excellent reproducibility for quantification of skeletal movements between two (CB)CT scans.

In Vivo Accuracy of a New Digital Planning System in Terms of Jaw Relation, Extent of Surgical Movements and the Hierarchy of Stability in Orthognathic Surgery

“…This limitation also applies to segmental osteotomies (2-piece-maxilla, Delaire-Joos, Zisser) as well as distractions and LeFort II or III surgeries. Measuring the accuracy of those surgical procedures CT or CBCT protocols with a reference to the cranial base are necessary where voxel-based registrations are preferred [ 35 , 36 , 37 , 38 ].…”

“…In contrast to landmark-based registrations, the semi-automated approach used here using best-fit alignment followed by the iterated closest-point algorithm over pVision3D [ 20 ] can be considered a strength of the study. Although the placement of landmarks has been confirmed to have high reproducibility, the error caused by the identification of the landmarks ranged from 0.02 to 2.47 mm [ 30 , 35 ]. Depending on the distance to the teeth, even a slight rotation around the centroid of the jaw can cause a significant bite opening or other malocclusion.…”

“… Overview of rotation errors (yaw, roll, and pitch) concerning studies on virtual planning in orthognathic surgery. Measurements of the present study compared to the results of three systematic reviews (Sys Rev) covering the years 2007–2020 [ 4 , 26 , 35 ]. …”

Virtual surgical analysis: long-term cone beam computed tomography stability assessment of segmental bimaxillary surgery

“…[5][6][7][8] Landmark reidentification errors have been shown to range from 0.02 mm to 2.47 mm. [9][10][11][12] The error may exceed the clinically relevant 0.5 mm margin, 13,14 and even the clinically acceptable surgical accuracy and stability of 2 mm. 4,8 Consequently, image registration techniques have been introduced for the superimposition of two consecutive uni-or multimodal scans based on a reference structure using mutual image information, [13][14][15][16][17][18][19][20][21] i.e.…”

“…[9][10][11][12] The error may exceed the clinically relevant 0.5 mm margin, 13,14 and even the clinically acceptable surgical accuracy and stability of 2 mm. 4,8 Consequently, image registration techniques have been introduced for the superimposition of two consecutive uni-or multimodal scans based on a reference structure using mutual image information, [13][14][15][16][17][18][19][20][21] i.e. voxel-based registration (VBR), [22][23][24] hence making the re-identification of landmarks superfluous.…”