Clinical Study of the Complications at Proximal Segment With Intraoral Vertical Ramus Osteotomy (IVRO); Related to the Osteotomy Line?

Kawase-Koga, Yoko

Clinical Study of the Complications at Proximal Segment With Intraoral Vertical Ramus Osteotomy (IVRO); Related to the Osteotomy Line?

Yoko Kawase-Koga DDS, PhD, Department of Oral and Maxillofacial Surgery, Tokyo Medical University, Tokyo, Japan

Yoshiyuki Mori DDS, PhD, Department of Oral and Maxillofacial Surgery, Dentistry and Orthodontics, The University of Tokyo Hospital, Tokyo, Japan

Yasuyuki Fujii DDS, Department of Oral and Maxillofacial Surgery, Dentistry and Orthodontics, The University of Tokyo Hospital, Tokyo, Japan

Yuki Kanno DDS, Department of Oral and Maxillofacial Surgery, Dentistry and Orthodontics, The University of Tokyo Hospital, Tokyo, Japan

Takahiro Abe DDS, PhD, Department of Oral and Maxillofacial Surgery, Dentistry and Orthodontics, The University of Tokyo Hospital, Tokyo, Japan

Masanobu Abe DDS, PhD, Department of Oral and Maxillofacial Surgery, Dentistry and Orthodontics, The University of Tokyo Hospital, Tokyo, Japan

Hideyuki Suenaga D.D.S., Ph.D., Department of Oral and Maxillofacial Surgery, Dentistry and Orthodontics, The University of Tokyo Hospital, Tokyo, Japan

Madoka Sugiyama DDS, Department of Oral and Maxillofacial Surgery, Dentistry and Orthodontics, The University of Tokyo Hospital, Tokyo, Japan

Hideto Saijo D.D.S., Ph.D., Department of Oral and Maxillofacial Surgery, Dentistry and Orthodontics, The University of Tokyo Hospital, Tokyo, Japan

Daichi Chikazu DDS, PhD, Department of Oral and Maxillofacial Surgery, Tokyo Medical University, Tokyo, Japan

Kazuto Hoshi MD, PhD, Department of Oral and Maxillofacial Surgery, Dentistry and Orthodontics, The University of Tokyo Hospital, Tokyo, Japan

Takafumi Susami D.D.S, Ph.D, Department of Oral and Maxillofacial Surgery, Dentistry and Orthodontics, The University of Tokyo Hospital, Tokyo, Japan

Tsuyoshi Takato M.D., Ph.D., Department of Oral and Maxillofacial Surgery, Dentistry and Orthodontics, The University of Tokyo Hospital, Tokyo, Japan

[Purpose]The intraoral vertical ramus osteotomy (IVRO) is widely used to correct mandibular prognathism and has several advantages over the sagittal split ramus osteotomy such as ease of procedure, reduced surgical time, minimal incidence of inferior alveolar nerve injury and less adverse events of the temporomandibular joint. However, several reports have been indicated IVRO technique has disadvantages such as condylar luxation and an interference of proximal segment. We hypothesize that these complications are related to the osteotomy line of IVRO. To evaluate this hypothesis, we investigated the incidence of condylar luxation and the interference of proximal segment following bilateral or unilateral IVRO focused on the osteotomy line. [Patients and Methods] IVRO was performed on 120 patients (185 sides) who had mandibular prognathism with and without Le Fort I osteotomy from August 2001 to December 2013. Out of 118 patients evaluated; 67 patients (134 sides) underwent bilateral IVRO surgical procedure, 51 patients (51 sides) underwent unilateral IVRO surgical procedure. The relative osteotomy line and complications were determined by panoramic x-ray after the operation. We classified osteotomy line into three types as follows; vertical type, C-shaped type, and oblique type. [Results]According to our classification of osteotomy line, vertical type consists of 98 sides, C-shaped type contains 37 sides, and oblique type had 50 sides. Interference of proximal segment occurred in 5 sides (2.7%), and all cases were showed vertical type of osteotomy line (5.1% in vertical type). Moreover, condylar luxation were found in 6 sides (3.2%) in which 4 cases indicated vertical type (4.1% in vertical types) and 2 cases demonstrated C-shaped type (5.4% in C-shaped type). [Conclusions] In this study, condylar luxation and an interference of proximal segment were observed in 5.9% (11/185) after IVRO. Interestingly, there were no complications in oblique type cases. These results suggest that oblique type of osteotomy line tend not to occur in the complications. [References] 1. Yamauchi K, Takenobu T, Takahashi T. Condylar luxation following bilateral intraoral vertical ramus osteotomy. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2007 Dec;104(6):747-51. 2. Ritto F, Parente E, da Silveira HM, Medeiros PJ, de Moraes M. Avoiding condylar displacement after intraoral vertical ramus osteotomy. J Craniofac Surg. 2010 May;21(3):826-9.