Achievability of 3D planned bimaxillary osteotomies: maxilla-first versus mandible-first surgery

Abstract

The present study was aimed to investigate the effects of sequencing a two-component surgical procedure for correcting malpositioned jaws (bimaxillary osteotomies); specifically, surgical repositioning of the upper jaw—maxilla, and the lower jaw—mandible. Within a population of 116 patients requiring bimaxillary osteotomies, the investigators analyzed whether there were statistically significant differences in postoperative outcome as measured by concordance with a preoperative digital 3D virtual treatment plan. In one group of subjects (n = 58), the maxillary surgical procedure preceded the mandibular surgery. In the second group (n = 58), the mandibular procedure preceded the maxillary surgical procedure. A semi-automated analysis tool (OrthoGnathicAnalyser) was applied to assess the concordance of the postoperative maxillary and mandibular position with the cone beam CT-based 3D virtual treatment planning in an effort to minimize observer variability. The results demonstrated that in most instances, the maxilla-first surgical approach yielded closer concordance with the 3D virtual treatment plan than a mandibular-first procedure. In selected circumstances, such as a planned counterclockwise rotation of both jaws, the mandible-first sequence resulted in more predictable displacements of the jaws.

One-year postoperative skeletal stability of 3D planned bimaxillary osteotomies: maxilla-first versus mandible-first surgery

“…With respect to our previous study 4 , which investigated the effects of sequencing bimaxillary osteotomies (maxilla-first versus mandible-first) on the achievability of the 3D virtually planned bimaxillary surgeries, it can be concluded that the sequence of surgery is more of clinical importance to the achievability of the 3D virtually planned repositioning of the jaws, rather than the stability of the achieved postoperative results. It is the surgeon’s choice to choose the most suitable sequence of bimaxillary osteotomies in each individual case.…”

“…The clinical cohort consisted of patients who underwent bimaxillary osteotomies at Radboud University Medical Centre between 2010 and 2014 (n = 116) 4 . In this one-year follow-up study, data from 106 patients (n = 73 female (69%); n = 33 male (31%); mean age 28 (range 16–57; Table 1)) were analysed to determine the level of skeletal relapse after undergoing either maxilla-first (n = 53) or mandible-first (n = 53) bi-maxillary surgery.…”

“…An accurate transfer of the 3D planned jaw positions to the patient is required to achieve the virtually planned positions of the jaws at the end of the operation. Recently our group has demonstrated that using the maxilla-first surgical approach, the 3D planned translational and rotational movements of the maxilla and mandible can be accomplished more accurately, compared to the mandibular-first approach 4 . However, in cases of bimaxillary CCW pitch, the mandible-first surgical approach is preferred because this sequence results in more predictable displacements of the jaws 3,4 .…”

A Complete Digital Workflow for Planning, Simulation, and Evaluation in Orthognathic Surgery

“…Another reason for the larger discrepancies in the impaction-elongation direction and pitch orientation might be caused by the bony interferences between the pterygoid plates and the posterior part of the osteotomized maxilla [41]. This could lead to deviations in the impaction-elongation direction and pitch orientation, as it is difficult to visually check the bony interferences during surgery [41,42].…”

Three-dimensional virtual surgical planning (3D-VSP) in orthognathic surgery: Advantages, disadvantages and pitfalls

“…Once a surgical plan has been formulated, virtual osteotomies are made. Maxilla-first surgery has been shown to be more predictable, except where the maxilla and mandible are both being rotated counter-clockwise, where mandible-first surgery is more predictable (Liebregts et al, 2017).…”