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Thoracic Pedicle Morphometry in Different Body Height Population: A Three-Dimensional Study Using Reformatted Computed Tomography

Zhuang, Zerui, MD*; Chen, Yuchun, PhD*; Han, Hui, MD*; Cai, Shijian, MD; Wang, Xinjia, PhD*; Qi, Weili, MD*; Kong, Kangmei, MD*

doi: 10.1097/BRS.0b013e318210f063
Anatomy
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Study Design. A three-dimensional study of the thoracic pedicle (T1–T12) morphometry in Chinese patients with different body height, using reformatted computed tomography (CT).

Objective. To quantify the dimensions of the thoracic pedicles and to analyze the relationship between body height and thoracic pedicle parameters.

Summary of Background Data. The thoracic pedicle morphometry has been studied extensively in different populations using various techniques. Previous studies have shown a significantly smaller size of the thoracic pedicles in women than in men and in Asians than in Caucasians. Some authors postulated that it is the body height that contributes to the variation in the pedicle size. To our knowledge, however, no study has specifically analyzed the relationship between body height and thoracic pedicle parameters in detail.

Methods. In this study, T1 to T12 vertebrae were imaged in 126 Chinese patients by a Lightspeed Vct CT (General Electric, Bridgeport, Connecticut, USA). After reformatting the original images, the following parameters were calculated: outer pedicle width, outer pedicle height and pedicle cortical thickness of the pedicle isthmus, pedicle length, and transverse pedicle angle. All measured data were statistically analyzed by the independent t test and Pearson correlation test using SPSS software (SPSS Inc, Chicago, IL).

Results. The thoracic pedicle parameters were significantly smaller in women than in men except for the transverse pedicle angles and the pedicle cortical thickness. The percentage of outer pedicle widths less than 4.5 mm was extremely high at T3 to T9 in females and T4 to T7 in males. There was a much higher percentage of pedicle width of 4.5 mm or lesser, 4.0 mm or lesser, and 3.5 mm or lesser when body height was less than 160 cm. Body height is probably one of the main factors that contribute to the variation in pedicle size since a significant positive correlation was observed between pedicle size and body height.

Conclusion. Body height is probably one of the main factors that contribute to the variation in pedicle size among different ethnic and sex groups. Transpedicular procedures using a 4.5-mm screw may not be applicable to much of the Chinese population at the upper and middle thoracic segments, especially for patients less than 160 cm in height. A reformatted CT evaluation is routinely recommended not only for choosing the proper screw but also for determining the feasibility of a true transpedicular procedure.

Previous studies have shown the thoracic pedicle size is smaller in females and in Asians. Some authors postulated that it is the body height that contributes to the variation. No further study to date has analyzed the relationship between body height and thoracic pedicle parameters in detail, which is the purpose of this study.

*Department of Orthopedic Surgery, Second Affiliated Hospital, Shantou University Medical College, Shantou, Guangdong, China

Department of Orthopedic Surgery, Zhongshan University Medical College, Guangdong, China.

Address correspondence and reprint requests to Kangmei Kong, MD, Department of Orthopedic Surgery, Second Affiliated Hospital, Shantou University Medical College, Shantou, Guangdong 515041, China; E-mail: kangmeikong@21cn.com

Acknowledgment date: May 3, 2010. First Revision date: July 21, 2010. Second Revision date: January 12, 2011. Acceptance date: January 17, 2011.

The manuscript submitted does not contain information about medical device(s)/drug(s).

No funds were received in support of this work. No benefits in any form have been or will be received from a commercial party related directly or indirectly to the subject of this manuscript.

Zerui Zhuang and Yuchun Chen contributed equally to this work and should be considered co-first authors.

© 2011 Lippincott Williams & Wilkins, Inc.