A 3-Dimensional Heat-mapping Evaluation Of Soft Tissue Changes Following Unilateral Vertical Mandibular Distraction Osteogenesis Among Patients With Hemifacial Microsomia
Rany Bous, BDS, MSD1, Rahma Elnaghy, BDS, MRCS1, Nima Khavanin, MD2, Richard Redett, III, MD2, Jordan Steinberg, MD, PhD2, Manish Valiathan, BDS, MDS, DDS, MSD1, Anand R. Kumar, MD, FACS, FAAP3.
1Case Western Reserve University, Cleveland, OH, USA, 2Johns Hopkins Hospital, Baltimore, MD, USA, 3University Hospitals Cleveland Medical Center, Cleveland, OH, USA.
PURPOSE: Unilateral vertical mandibular distraction osteogenesis (UVMD) is a common interceptive treatment approach for addressing asymmetries among patients with Hemifacial Microsomia (HFM). While numerous studies have evaluated the skeletal changes associated with UVMD, there is a relative paucity of information on the soft tissue changes. The purpose of this study was to utilize 3-Dimensional (3D) superimpositions and color mapping to evaluate the soft tissue changes associated with UVMD.
METHODS: This retrospective study included 5 patients with HFM that were consecutively treated with UVMD. All patients had Cone-Beam Computed Tomography (CBCT) scans obtained preoperatively (T1) and postoperatively at 3 or more months post-consolidation (T2). The CBCT volumes were imported into Dolphin 3D software, which was used to generate a soft-tissue surface. Soft-tissue surfaces at T1 and T2 were superimposed to the best fit and a heat map was generated using Dolphin 3D software to evaluate the changes. Because the software does not allow quantification of changes more than 5mm, the heat map was generated three times with thresholds of 3mm, 4mm, and 5mm.
RESULTS: The distracted ipsilateral side's cheek area and gonial angle showed apparent changes at the 3mm threshold (Image 1), and to a lesser extent at the 4mm threshold (Image 2). The chin and the contralateral side's gonial angle showed the greatest changes, mapped at 5mm or more (Image 3).
CONCLUSION: The greatest changes associated with UVMD were shown at the chin and gonial angle of the contralateral side, indicating that while the chin asymmetry may be corrected by UVMD, the soft tissue deficiency of the affected side may not be resolved. Our findings support the need for considering fat grafting of the affected side to allow for optimizing symmetry and esthetics for patients with HFM.
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