A discussion of an accurate maxillary superior repositioning technique without intraoperative measurement in bimaxillary orthognathic surgery

We read the article by Omura et al. with great interest. The authors present a technique for maxillary superior repositioning in bimaxillary orthognathic surgery that can additionally be used for condylar positioning, which is very interesting. Nonetheless, three points deserve further discussion.

Firstly, the authors mention that ‘there has been no report of a technique that controls the position of both the maxilla and mandible simultaneously’. Although the use of locking plates is innovative, similar techniques for both maxillary and condylar repositioning using non-locking plates have already been reported.

Secondly, some of the presumed advantages of the technique can be questioned. The authors state that locking plates provide greater stability than their non-locking counterparts, and more than a Kirschner wire, and hence maxillary repositioning would be more precise using locking plates. Kretschmer et al. using non-locking plates as positioning devices for maxillary repositioning found them to be less precise than Gil’s K-wire in the craniocaudal axis (+0.75 (1.09) mm versus 0.23 mm).

Not having to maintain the position of the maxilla by hand when fixating it sounds very interesting, but it is highly debatable if the fact that the plates can act as a condylar positioning device (CPD) is indeed an advantage. A literature review on CPDs raised important questions about their use. A more recent review on the same subject found that there is no scientific evidence to support the routine use of CPDs. Furthermore, Ueki et al., in a review concerning the desired postoperative position of the condyle, suggested that the preoperative position might not be the desired postoperative one.

Thirdly, Omura et al. do not mention any disadvantages of the technique, yet others report a number of them. Wider or additional incisions are necessary ; no intraoperative control is possible ; operating time is longer ; even the longest plate might be too short, especially when performing a high level maxillary osteotomy; there can be difficulties in adaptation using only one plate (per side); it is necessary to readapt the plate to a new site if one of the fixation sites fails; because of its extraordinary length, the plate shows a higher tendency to distortion and twisting during positioning procedures; it can be difficult to reapply the plate after extensive advancement of the maxilla.

Besides the already reported disadvantages, others can be postulated. For example, by maintaining the preoperative position of the condyles, autorotation of the mandibular ramus is prevented, which can be problematic for a number of reasons. It might cause bony interferences along the horizontal superior bone cut of the bilateral sagittal split osteotomy, requiring recontouring. It might also influence the alignment between the proximal and distal segments at the inferior border of the mandible, which in turn might: reduce bony overlap; make it more difficult to fixate the segments; and create an unaesthetic step deformity. Furthermore, all devices for isolated maxillary or bimaxillary surgery depend on some autorotation of the mandible and whether the condyle will rotate around the same intercondylar axis as determined by the positioning device is unknown.

Despite the reported disadvantages, the idea behind the technique seems promising; it may be worth running more studies to further improve it.

Competing interests

None declared.

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Jan 24, 2018 | Posted by in Oral and Maxillofacial Surgery | Comments Off on A discussion of an accurate maxillary superior repositioning technique without intraoperative measurement in bimaxillary orthognathic surgery
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