Three dimensional evaluation of facial asymmetry after mandibular reconstruction: validation of a new method using stereophotogrammetry

doi:10.1016/j.ijom.2012.05.036

International Journal of Oral and Maxillofacial Surgery

Volume 42, Issue 1, January 2013, Pages 19-25

https://doi.org/10.1016/j.ijom.2012.05.036 Get rights and content

Abstract

The scientific literature is sparse on reports that evaluate facial asymmetry after mandibular reconstructive surgery objectively. The aim of this study is to introduce and validate a new method, using three dimensional (3D) stereophotogrammetry, that quantifies soft-tissue facial asymmetry in patients who have undergone mandibular reconstruction. To validate the new method, two observers applied the method on 3D photographs of five patients and five controls. An inter-observer difference of 0.04 mm (−0.08 to 0.17) was found with a measurement error of 0.13 mm. 15 3D photographs of the mandibular reconstructed patients were compared with 24 3D photographs of healthy controls. A significant difference (1.19 mm) in asymmetry was found between patients and controls. It is concluded that this new measuring method is a valid, fast and clinically applicable technique to quantify soft-tissue facial asymmetry. It is concluded that facial symmetry in patients is not restored to the level of the control group with the mandibular reconstruction method applied.

Section snippets

Materials and methods

20 patients who underwent immediate or delayed mandibular reconstruction because of a segmental resection in the period 2000–2009 were included in this study.¹⁰ In all 20 patients the reconstruction was performed with two preshaped titanium 2.3 mm plates (Smart plates; KLS Martin Group, Tuttlingen, Germany), particulate autogenous cancellous bone graft and platelet-rich plasma.10, 11 A group of 24 healthy volunteers with no history of facial surgery or existing facial deformities served as

Results

Intra- and inter-observer performances are presented in Table 1. The absolute mean asymmetry, of all corresponding points compared in an x, y, z coordinate system, has an intra-observer difference of 0.02 mm (−0.07 to 0.11) with a measurement error of 0.09 mm. The inter-observer difference is 0.04 mm (−0.08 to 0.17) with a measurement error of 0.13 mm. Both are well within the 0.5 mm range which is considered to be acceptable.16, 17

In five patients, 3D photographs could not be used because of image

Discussion

Measuring asymmetry using 3D stereophotogrammetry has been done in cleft lip and palate¹⁸ and orthognathic patients.¹⁹ A 3D optical sensor has been used before to measure asymmetry in cleft lip and palate patients.20, 21 In these studies a symmetry axis was computed. To measure asymmetry the distance of cephalometric soft-tissue landmarks to the symmetry axis was calculated. These landmarks were all situated close to the symmetry axis (most lateral landmarks were ExL and ExR). More lateral

Funding

None.

Ethical approval

No ethical approval was required for the current study.

Competing interests

None declared.

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The aim of this study was to investigate changes in facial soft tissue asymmetry over time after orthognathic surgery in Class III patients using three-dimensional stereophotogrammetry. The study included 101 patients with a skeletal Class III malocclusion (72 female, 29 male; age range 19–53 years, mean age 28.6 years) who underwent orthognathic surgery. The minimum follow-up was 12 months. Three-dimensional photographs were acquired using the 3dMDtrio stereophotogrammetry system, and 21 anthropometric landmark positions were evaluated at three time points: before surgery (T0), 6 months (T1) and 12 months (T2) after surgery. Facial asymmetry was assessed and classified as follows: 0–2 mm, mild; 2–5 mm, moderate;> 5 mm, severe. The average distance for whole face asymmetry differed between T0 (median 0.76 mm) and T1 (median 0.70 mm); however, there was no statistically significant difference at any time point. The chin volume asymmetry score differed significantly between T0 (median 1.11 mm) and T1 and T2 (median 1.08 mm for both; P < 0.001 and P = 0.001, respectively), but not between T1 and T2 (P = 0.061). The study findings indicate that the asymmetry of the facial soft tissues has the potential to return after 6 months, without reaching the baseline.
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Citation Excerpt :
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^☆: This work was supported by a grant from the Dutch Technology Foundation (STW – nr. 10315).

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Research PaperImagingThree dimensional evaluation of facial asymmetry after mandibular reconstruction: validation of a new method using stereophotogrammetry☆

Abstract

Section snippets

Materials and methods

Results

Discussion

Funding

Ethical approval

Competing interests

Oral Oncol

J Oral Maxillofac Surg

Int J Oral Maxillofac Surg

Int J Oral Maxillofac Surg

Int J Oral Maxillofac Surg

J Oral Maxillofac Surg

Int J Oral Maxillofac Surg

Br J Oral Maxillofac Surg

J Craniomaxillofac Surg

Int J Oral Maxillofac Surg

J Oral Maxillofac Surg

Am J Orthod Dentofacial Orthop

J Craniomaxillofac Surg

J Oral Maxillofac Surg

Research Paper
Imaging
Three dimensional evaluation of facial asymmetry after mandibular reconstruction: validation of a new method using stereophotogrammetry☆