Volumetric change of the muscles of mastication following resection of mandibular angles: a long-term follow-up

Ann Plast Surg. 2005 Jun;54(6):615-21; discussion 622. doi: 10.1097/01.sap.0000157879.22779.3f.


Mandibular angle resection is an accepted procedure for the correction of square face appearance due to mandibular angle prominence. Long-term follow-up of the changes in volume that occurs in the muscles of mastication and osseous structures has been inadequate in the literature. In this study, 3-dimensional computed tomography data were used to extract the mandible, masseter, medial pterygoid, and lateral pterygoid muscles for assessment of the volumetric changes that took place after angle reduction in 7 patients (14 hemimandibles) with an average age of 24.9 years and a mean follow-up time of 4.5 years. All measurements were performed twice to assure accuracy, with a difference of 1.2 +/- 1.1% noted. The hemimandible volume was reduced by 12.6% immediately after the reduction procedure and 8.2% at final follow-up. Osseous regeneration was observed as thickening of the bone and partial regrowth of the angles. None of the 14 hemimandibles had a complete return of the preoperative angular shape. The volumetric changes that occurred in the muscles of mastication were inconsistent among the patients. The masseter muscle was reduced by 5.2%, the medial pterygoid muscle was reduced by 14.4%, and the lateral pterygoid muscle was increased by 5.7% at final follow-up. The medial pterygoid muscle change was more significant than that of the masseter muscle (P = 0.00361). The objective findings of this study were not in agreement with the conventional thought and clinical impression that the masseter muscle becomes atrophic after mandibular angle resection. Only a slight reduction occurred in some patients in the volume of the muscles, with some actually displaying a slight increase. The end result was a satisfactory esthetic outcome for the patients in the long term despite the minor changes in muscle volume and slight bony regeneration that occurred.

MeSH terms

  • Adolescent
  • Adult
  • Female
  • Follow-Up Studies
  • Humans
  • Imaging, Three-Dimensional
  • Male
  • Mandible / diagnostic imaging
  • Mandible / surgery*
  • Masticatory Muscles / diagnostic imaging*
  • Masticatory Muscles / physiology
  • Muscular Atrophy / diagnostic imaging*
  • Plastic Surgery Procedures / methods*
  • Tomography, X-Ray Computed / methods*