Diagnostic and therapeutic approach to unilateral posterior vertical insufficiency

The aim of this article is to present the diagnostic and therapeutic approach to unilateral posterior vertical insufficiency.

The authors describe the management protocol.

Posterior vertical insufficiency (PVI) manifests clinically as obliquity of the maxillo-mandibular occlusal plane and bicommissural line, and deviation of the chin. Radiographically, PVI is characterized by an elevation of the mandibular angle in relation to the base of the odontoid. Among the etiologies, congenital disorders are the most frequent, dominated by condyle hypoplasia. First and second branchial arches syndromes are most often associated to soft-tissue malformations, while acquired etiologies (post-traumatic, ankylosis and rheumatic) are scarce. Therapeutic management requires close collaboration between orthodontist and surgeon and involves alternative orthognathic surgical procedures. Three techniques are described along with their expected results: chondro-costal grafting, vertical retro-spinal lengthening using the Caldwell-Letterman technique, and intra-oral supra-basilar osteotomy.

Although the clinical presentation can be frustrating in children, facial asymmetry usually increases during pubertal growth. Early treatment with dentofacial orthopedics can sometimes restore growth. In other cases, collaboration between orthodontist and surgeon is more necessary than ever to correct asymmetry, sometimes using unconventional surgical technique.