Surgical Intervention for Masticatory Muscle Tendon-Aponeurosis Hyperplasia Based on the Diagnosis Using the Four-Dimensional Muscle Model.
OBJECTIVE
The surgical target of Masticatory muscle tendon-aponeurosis hyperplasia (MMTAH) is the masseter or temporal muscle. In our clinic, the 4-dimentional muscle model (4DMM) has been used to decide if we should approach to the masseter or temporal muscle. The aim of this study is validate the clinical usefulness of 4DMM on the basis of the surgical results.


METHODS
The 4DMM was constructed from the digital data of 3D-CT and 4-dimentional mandibular movements of the patients. It made us to able to visually observe the expansion rate of masticatory muscles at maximum mouth opening comparing to their length at closed mouth position. Fifteen patients were applied the 4DMM before the surgical treatment and 2 healthy volunteers were enrolled as control group.


RESULTS
The expansion rate of temporal muscle at the maximum mouth opening in the patient group was significantly less than that in the control group (P < 0.05). On the other hand, the masseter muscles of all patients were expanded as same as the control group. Therefore the main cause of limitation of mouth-opening was suggested to be a contracture of the temporal muscle. Consequently, we performed successful bilateral coronoidectomy with no surgical intervention to the masseter muscles in all patients.


CONCLUSIONS
The present 4DMM would be valuable modality to decide the target muscle of surgical treatment for patients with MMTAH. In this pathology, contracture of the temporal muscle seems to be main cause of limited mouth opening.
*Department of Oral and Maxillofacial Surgery, Tsurumi University School of Dental Medicine †Department of Oral and Maxillofacial Surgery, Yokohama Rosai Hospital ‡Department of Fixed Prosthodontics, Tsurumi University School of Dental Medicine §Department of Oral and Maxillofacial Radiology and Diagnosis, Tsurumi University School of Dental Medicine, Yokohama, Japan.
Kazutoshi
K
Nakaoka
Yoshiki
Y
Hamada
Hayaki
H
Nakatani
Yuko
Y
Shigeta
Shinya
S
Hirai
Tomoko
T
Ikawa
Akira
A
Mishima
Takumi
T
Ogawa
D000328:Adult; D000368:Aged; D003286:Contracture / Q000175:diagnosis / Q000601:surgery; D003936:Diagnosis, Computer-Assisted / Q000379:methods*; D005081:Exercise Therapy; D005205:Fascia / Q000473:pathology; D000071938:Fasciotomy; D005260:Female; D006801:Humans; D006965:Hyperplasia / Q000473:pathology; D021621:Imaging, Three-Dimensional / Q000379:methods; D008297:Male; D008334:Mandible / Q000473:pathology / Q000503:physiopathology / Q000601:surgery; D008335:Mandibular Condyle / Q000473:pathology / Q000503:physiopathology; D008406:Masseter Muscle / Q000473:pathology*; D008875:Middle Aged; D009068:Movement; D010347:Patient Care Planning; D025321:Surgery, Computer-Assisted / Q000379:methods*; D013703:Temporal Muscle / Q000473:pathology / Q000601:surgery*; D013710:Tendons / Q000473:pathology / Q000601:surgery*; D014057:Tomography, X-Ray Computed / Q000379:methods; D014584:User-Computer Interface; D055815:Young Adult