Prediction of 3-dimensional pharyngeal airway changes after orthognathic surgery: A methodological issue

Abstract

I was interested to read the article by Brunetto and colleagues published in the September 2014 edition of the Journal.1Brunetto D.P. Velasco L. Koerich L. Araújo M.T. Prediction of 3-dimensional pharyngeal airway changes after orthognathic surgery: a preliminary study.Am J Orthod Dentofacial Orthop. 2014; 146: 299-309Abstract Full Text Full Text PDF PubMed Scopus (43) Google Scholar The purpose of the authors was to correlate the amount of jaw displacement with the volume variation and the minimal cross-sectional area of the pharyngeal airway.I found the title to be incorrect because, for prediction purposes, using the Pearson correlation test is a common mistake.2Jeckel J.F. Katz D.L. Elmore J.G. Wild D.M. The study of causation in epidemiologic investigation and research.in: Jeckel J.F. Epidemiology, biostatistics and preventive medicine. 3rd ed. Saunders Elsevier, Philadelphia2007: 64-66Google Scholar, 3Rothman K.J. Greenland S. Lash T.L. Cohort studies.in: Rothman K.J. Modern epidemiology. 3rd ed. Lippincott Williams and Wilkins, Baltimore2008: 79-85Google Scholar, 4Sabour S. Obesity predictors in people with chronic spinal cord injury: a common mistake.J Res Med Sci. 2014; 19: 80PubMed Google Scholar Moreover, for prediction studies, we need 2 different cohort data sets or at least a split cohort data set to develop our prediction model and then validate it. So, appropriate study design as well as validating our model should be considered in prediction studies.2Jeckel J.F. Katz D.L. Elmore J.G. Wild D.M. The study of causation in epidemiologic investigation and research.in: Jeckel J.F. Epidemiology, biostatistics and preventive medicine. 3rd ed. Saunders Elsevier, Philadelphia2007: 64-66Google Scholar, 3Rothman K.J. Greenland S. Lash T.L. Cohort studies.in: Rothman K.J. Modern epidemiology. 3rd ed. Lippincott Williams and Wilkins, Baltimore2008: 79-85Google Scholar, 4Sabour S. Obesity predictors in people with chronic spinal cord injury: a common mistake.J Res Med Sci. 2014; 19: 80PubMed Google ScholarBrunetto et al concluded that only the maxillary displacement is a reliable predictor of the minimal cross-sectional area variation after maxillomandibular advancement. Such a conclusion may lead to a misleading message and mismanagement of the patients. I was interested to read the article by Brunetto and colleagues published in the September 2014 edition of the Journal.1Brunetto D.P. Velasco L. Koerich L. Araújo M.T. Prediction of 3-dimensional pharyngeal airway changes after orthognathic surgery: a preliminary study.Am J Orthod Dentofacial Orthop. 2014; 146: 299-309Abstract Full Text Full Text PDF PubMed Scopus (43) Google Scholar The purpose of the authors was to correlate the amount of jaw displacement with the volume variation and the minimal cross-sectional area of the pharyngeal airway. I found the title to be incorrect because, for prediction purposes, using the Pearson correlation test is a common mistake.2Jeckel J.F. Katz D.L. Elmore J.G. Wild D.M. The study of causation in epidemiologic investigation and research.in: Jeckel J.F. Epidemiology, biostatistics and preventive medicine. 3rd ed. Saunders Elsevier, Philadelphia2007: 64-66Google Scholar, 3Rothman K.J. Greenland S. Lash T.L. Cohort studies.in: Rothman K.J. Modern epidemiology. 3rd ed. Lippincott Williams and Wilkins, Baltimore2008: 79-85Google Scholar, 4Sabour S. Obesity predictors in people with chronic spinal cord injury: a common mistake.J Res Med Sci. 2014; 19: 80PubMed Google Scholar Moreover, for prediction studies, we need 2 different cohort data sets or at least a split cohort data set to develop our prediction model and then validate it. So, appropriate study design as well as validating our model should be considered in prediction studies.2Jeckel J.F. Katz D.L. Elmore J.G. Wild D.M. The study of causation in epidemiologic investigation and research.in: Jeckel J.F. Epidemiology, biostatistics and preventive medicine. 3rd ed. Saunders Elsevier, Philadelphia2007: 64-66Google Scholar, 3Rothman K.J. Greenland S. Lash T.L. Cohort studies.in: Rothman K.J. Modern epidemiology. 3rd ed. Lippincott Williams and Wilkins, Baltimore2008: 79-85Google Scholar, 4Sabour S. Obesity predictors in people with chronic spinal cord injury: a common mistake.J Res Med Sci. 2014; 19: 80PubMed Google Scholar Brunetto et al concluded that only the maxillary displacement is a reliable predictor of the minimal cross-sectional area variation after maxillomandibular advancement. Such a conclusion may lead to a misleading message and mismanagement of the patients. Prediction of 3-dimensional pharyngeal airway changes after orthognathic surgery: A preliminary studyAmerican Journal of Orthodontics and Dentofacial OrthopedicsVol. 146Issue 3PreviewRecent studies have shown some contradictory results when evaluating the consequences of orthodontic-surgical treatments on the pharyngeal airway. Therefore, the purpose of this study was to correlate the amount of jaw displacement with the volume variation and the minimal cross-sectional area of the pharyngeal airway. A comparison was made between the correlations with the percentage and the absolute values of the measurement variations. Full-Text PDF Authors' responseAmerican Journal of Orthodontics and Dentofacial OrthopedicsVol. 147Issue 1PreviewWe appreciate the interest and comments of Dr Sabour regarding our recent article “Prediction of 3-dimensional pharyngeal airway changes after orthognathic surgery: A preliminary study” (Brunetto DP, Velasco L, Koerich L, Araújo MT. Am J Orthod Dentofacial Orthop 2014;146:299-309). Full-Text PDF