Wednesday, October 26, 2011

New Method of Scoliosis Assessment

From Spine Preliminary Results Using Computerized Photogrammetry Rozilene Maria Cota Aroeira, MSc; Jefferson Soares Leal, MD; Antônio Eustáquio de Melo Pertence, PhD Posted: 09/26/2011; Spine. 2011;36(19):1584-1591. © 2011 Lippincott Williams & Wilkins Study Design. A new method for nonradiographic evaluation of scoliosis was independently compared with the Cobb radiographic method, for the quantification of scoliotic curvature. Objective. To develop a protocol for computerized photogrammetry, as a nonradiographic method, for the quantification of scoliosis, and to mathematically relate this proposed method with the Cobb radiographic method. Summary of Background Data. Repeated exposure to radiation of children can be harmful to their health. Nevertheless, no nonradiographic method until now proposed has gained popularity as a routine method for evaluation, mainly due to a low correspondence to the Cobb radiographic method. Methods. Patients undergoing standing posteroanterior full-length spine radiographs, who were willing to participate in this study, were submitted to dorsal digital photography in the orthostatic position with special surface markers over the spinous process, specifically the vertebrae C7 to L5. The radiographic and photographic images were sent separately for independent analysis to two examiners, trained in quantification of scoliosis for the types of images received. The scoliosis curvature angles obtained through computerized photogrammetry (the new method) were compared to those obtained through the Cobb radiographic method. Results. Sixteen individuals were evaluated (14 female and 2 male). All presented idiopathic scoliosis, and were between 21.4 ± 6.1 years of age; 52.9 ± 5.8 kg in weight; 1.63 ± 0.05 m in height, with a body mass index of 19.8 ± 0.2. There was no statistically significant difference between the scoliosis angle measurements obtained in the comparative analysis of both methods, and a mathematical relationship was formulated between both methods. Conclusion. The preliminary results presented demonstrate equivalence between the two methods. More studies are needed to firmly assess the potential of this new method as a coadjuvant tool in the routine following of scoliosis treatment. Introduction Scoliosis has been defined as a lateral curvature of the spinal column superior to 10° Cobb, generally associated to vertebral rotation. Monitoring of this angle has been one of the principal parameters used in defining the type of treatment to be instituted in young patients who are still growing. The most trustworthy method to accompany the evolution of the curvature has been the standing posteroanterior full length spine radiograph, with curvature measurement using the Cobb method.[3] However, over the course of follow-up, this can result in taking more than 25 radiographs. Nearly 15% of patients in one study had undergone 50 or more radiographic examinations, and approximately 17% had received an estimated cumulative radiation dose of 20 cGy or greater. This high number of radiographs can expose patients to relatively high doses of ionizing radiation. Various studies have shown that repeated exposure to radiation in children could be harmful to their health. Many nonradiographic methods of scoliosis accompaniment have been proposed as an alternative to radiographic evaluation.Nevertheless, the majority has not demonstrated a good correlation with the Cobb method. Photogrammetry can be regarded as the science and technology of obtaining spatial measurements, and other geometrically reliable information, derived from photographs.The computerized photogrammetry method proposed in this study can be considered one of many uses of photogrammetry. It has been used in different fields, such as: cartography, architecture, engineering, quality control, and three-dimensional modeling. However, its use in the evaluation of scoliosis has not been well studied. To the authors' knowledge, no data are presently available in the literature that proposes a protocol for photogrammetric measurement of scoliosis, which is applicable to clinical practice. The goals of this investigation were to develop a protocol for computerized photogrammetry method for the quantification of scoliosis curvature as well as to compare the results with those from the Cobb radiographic method in the group of volunteers. Our hypothesis is that both methods yield similar results in obtaining the scoliosis curvature angle.

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