Imaging of Mandible and Temporomandibular Joint Surgery
Intraoral vertical ramus osteotomy is a treatment option for mandibubular prognatism. In this technique, a vertically oriented cut made in the mandibular ramus allows the condyle to be lowered and the temporomandibular joint disc to recapture (Fig. 8.1).
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Imaging of Mandible and Temporomandibular Joint Surgery Daniel Thomas Ginat and Per-Lennart A. Westesson
8.1
Vertical Ramus Osteotomy
8.1.1
Discussion
Intraoral vertical ramus osteotomy is a treatment option for mandibubular prognatism. In this technique, a vertically oriented cut made in the mandibular ramus allows the condyle to be lowered and the temporomandibular joint
disc to recapture (Fig. 8.1). The procedure yields satisfactory results and has fewer complications than intra-articular techniques. Expected changes following vertical ramus osteotomy that can be appreciated on imaging include cortical bone thickening, narrowing of the bone marrow space, medial tilting of the mandibular condyle, and masticator muscle atrophy (Fig. 8.2).
D.T. Ginat, M.D., M.S. () Department of Radiology, Harvard Medical School, Massachusetts General Hospital, Boston, MA, USA e-mail: [email protected] P.-L.A. Westesson, M.D., Ph.D., DDS Division of Neuroradiology, University of Rochester Medical Center, Rochester, NY, USA D.T. Ginat, P.-L.A. Westesson, Atlas of Postsurgical Neuroradiology, DOI 10.1007/978-3-642-15828-5_8, © Springer-Verlag Berlin Heidelberg 2012
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Imaging of Mandible and Temporomandibular Joint Surgery
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Fig. 8.1 Vertical ramus osteotomy. The patient has a history of temporomandibular joint disc dysfunction. Panorex (a) and lateral radiograph (b) show a unilateral left mandibular ramus vertical osteotomy (arrows)
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Fig. 8.2 Muscle atrophy. Axial (a) and coronal (b) CT images show mildly decreased bulk of the masticator muscles on the right (arrows), ipsilateral to where vertical ramus osteotomy was performed
8.2
Sagittal Split Osteotomy
8.2.1
Discussion
The sagittal split osteotomy is a commonly performed procedure for correcting maxillofacial deformities, such as mandibular hypoplasia or hyperplasia. The surgery consists of bilateral osteotomies through the mandibular ramus with either advancement or setback of the mandibular
body (Fig. 8.3). The osteotomy can be secured via rigid fixation or wire fixation. Sagittal split osteotomies are sometimes combined with other types of maxillofacial procedures, such as the LeFort I osteotomy. Dysesthesia of the inferior alveolar nerve is one of the most common complications since the osteotomy is in the region of the inferior alveolar nerve. Facial nerve palsy and maxillary nerve pseudoaneurysm are rare complications of the sagittal split surgery.
8.3
Genioplasty
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Fig. 8.3 Sagittal split osteotomy. The patient has a history of maxillary hypoplasia and transverse discrepancy and mandibular hyperplasia. Axial (a) and posterior 3D CT
(b) images show osteotomies through the mandibular rami with screw fixation providing near-anatomic alignment of the mandible
8.3
Genioplasty
8.3.1
Discussion
The osteotomy is performed well below the dental roots and mental foramina in order to avoid complications. Prostheses can be used for lengthening genioplasty, such as those composed of silicone, either alone or in conjunction with a
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