How to revise and utilise the cephalogram for craniofacial dysostosis—Modification of the porion and the McNamara line☆
Received 11 July 2008; accepted 5 November 2009. published online 30 November 2009.
Summary
McNamara line analysis is often utilised in orthognathic surgery and is particularly useful in that it can easily express the extent of maxillo-mandibular deformity quantitatively. However, in craniofacial dysostosis (CFD), the location of the porion (PR) is sometimes displaced inferiorly. The McNamara line depends on the Frankfurt horizontal plane (FH plane), and hence, its deviation is often extremely distorted in CFD.
The objective of this study was to enable more correct reflection of deformities of CFD patients on lateral cephalogram analysis. The lateral cephalograms of 152 Asian individuals were involved. ∠basion(BA).orbitale(Or).PR, ∠BA. nasion(NA).PR, and the distance from BA to PR on the BA-NA plane were measured and each standard range was established. Using these ranges, modified PR (mPR) is supposed to lie within a fairly small area.
Second, we utilised mPR in the practice of McNamara line analysis in CFD patients. In both cases in the present study, it was confirmed that modified McNamara line analysis can express the deformities more precisely than conventinal analysis, as far as the maxillo-mandibular relationship is concerned. However, particularly in Case 2, both the cranio-maxillary and cranio-mandibular relationships were not entirely consistent with the lateral profile appearance even on modified McNamara line analysis.
1Department of Plastic and Reconstructive Surgery, Keio University School of Medicine, 35 Shinanomachi Shinjuku-ku, Tokyo 160-8582, Japan
2Department of Orthodontics, Tokyo Dental College, 1-2-2 Masago Mihama-ku, Chiba city, Chiba 261-8502, Japan
Ikkei TAMADA, MD Department of plastic and reconstructive surgery, Keio university school of medicine, 35 Shinanomachi Shinjuku-ku, Tokyo 160-8582 Japan. Tel.: +81 3 5363 3814; Fax: +81 3 3352 1054.
☆ This work was partly presented at the 25th annual meeting of Japan Society of Cranio-Maxillo-Facial Surgery, the 50th annual meeting of Japan Society of Plastic and Reconstructive Surgery and the 51th annual meeting of Japan Society of Plastic and Reconstructive Surgery.
ABSTRACT