Three-dimensional attachment morphometry and volumetric changes of masticatory muscles after free fibular flap reconstruction of the mandibular condyle

Abstract

This retrospective case-series study aimed to elucidate the three-dimensional attachment morphometric features and to quantify the volumetric changes of the masticatory muscles following free fibular flap reconstruction of the mandibular condyle. Navigation software (iPlan, version 3.0; Brainlab) was used to perform delineation and volumetric measurement of the masticatory muscles using DICOM data.In total, 30 patients were included in this retrospective case series. In 25 cases (83.33%), the lateral pterygoid muscle achieved reattachment within 6 months postoperatively. The medial pterygoid muscles on the affected side achieved ectopic attachment in all cases. However, masseter reattachment on the affected side was achieved in only three cases. On the normal side, the volumes of lateral pterygoid muscle, medial pterygoid muscle, and masseter had recovered to almost preoperative levels at 1 year postoperatively. On the affected side, the volume of medial pterygoid muscle had decreased significantly (p = 2.4e-04) at 3 months postoperatively. The volumes of lateral pterygoid muscle and masseter showed mild decreases at 3 months postoperatively, but these were not significant (p = 0.52 and p = 0.05 for the pterygoid muscle and masseter, respectively). At 6 months after surgery, with the exception of the volume of the lateral pterygoid muscle (p = 0.06), the total volume of the masticatory muscles decreased significantly on the affected side. The volumes of lateral pterygoid muscle, medial pterygoid muscle, and masseter showed significant decreases at 1 year postoperatively (p = 0.03, p = 4.7e-08, and p = 1.1e-05, respectively) on the affected side. The postoperative volumes of the masseter, medial pterygoid, and lateral pterygoid muscles showed significant decreases due to the loss of reattachment.The results of this study may not help to ascertain whether reattachment of masticatory muscles will lead to better function. As a consequence, clinical trials of higher quality are needed.