Analysis of Pelvic Incidence From 3-Dimensional Images of a Normal Population

Study Design. Pelvic incidence (PI) was measured in 3 dimensions from computed tomographic (CT) images of normal subjects using a computerized method. Objective. To obtain the angle of PI from 3-dimensional (3D) images and analyze its distribution in a normal population. Summary of Background Data. The sagittal alignment of the pelvis is usually evaluated in 2-dimensional (2D) sagittal radiographs. The purpose of this study is to measure and analyze PI, which represents a key parameter of sagittal alignment, in 3D images. Methods. A computerized method, based on image-processing techniques, was used to automatically determine the anatomical references required to measure PI, that is, the centers of the femoral heads in 3 dimensions and the center and inclination of the sacral end plate in 3 dimensions. Multiplanar image reformation was applied to obtain perfect sagittal views with all anatomical structures completely in line with the hip axis from which PI was calculated. Results. PI was successfully obtained in CT images of 370 normal subjects (mean age: 41.5 years; range: 1–87 years). The mean PI (± standard deviation) was equal to 46.6° (±9.2°) for male subjects, 47.6° (±10.7°) for female subjects, and 47.1° (±10.0°) for both sexes. No statistically significant differences were obtained between the sexes, and statistically significant correlation was obtained between PI and age. Conclusion. In this study, the sagittal alignment of the pelvis was evaluated in terms of PI completely in 3 dimensions. The results show that computerized measurements of PI in 3 dimensions are less variable than manual measurements. The large span of PI values for normal subjects indicates that the natural variation of PI is relatively large.

[1]  S. Hansen,et al.  Sagittal alignment in lumbosacral fusion: relations between radiological parameters and pain , 2000, European spine journal.

[2]  K. Wood,et al.  Sagittal Profile of the Elderly , 2003, Journal of spinal disorders & techniques.

[3]  Wafa Skalli,et al.  Gravity Line Analysis in Adult Volunteers: Age-Related Correlation With Spinal Parameters, Pelvic Parameters, and Foot Position , 2006, Spine.

[4]  Ashish Patel,et al.  Sagittal Plane Considerations and the Pelvis in the Adult Patient , 2009, Spine.

[5]  O. Müller,et al.  Adjustment of pelvispinal parameters preserves the constant gravity line position , 2007, International Orthopaedics.

[6]  L. Lenke,et al.  Correlation of Pelvic Incidence With Low- and High-Grade Isthmic Spondylolisthesis , 2002, Spine.

[7]  Hubert Labelle,et al.  Sagittal Plane Analysis of the Spine and Pelvis in Adolescent Idiopathic Scoliosis According to the Coronal Curve Type , 2003, Spine.

[8]  Ashish Patel,et al.  Pelvic Tilt and Truncal Inclination: Two Key Radiographic Parameters in the Setting of Adults With Spinal Deformity , 2009, Spine.

[9]  Hae-Ryong Song,et al.  Correlation of Pelvic Orientation With Adult Scoliosis , 2010, Journal of spinal disorders & techniques.

[10]  B. Boisaubert,et al.  The sagittal anatomy of the sacrum among young adults, infants, and spondylolisthesis patients , 2002, European Spine Journal.

[11]  S. Weinstein,et al.  Natural History of Spinopelvic Alignment Differs From Symptomatic Deformity of the Spine , 2010, Spine.

[12]  J. Buchowski,et al.  Role of Pelvic Incidence, Thoracic Kyphosis, and Patient Factors on Sagittal Plane Correction Following Pedicle Subtraction Osteotomy , 2009, Spine.

[13]  Pierre Roussouly,et al.  Sagittal plane deformity: an overview of interpretation and management , 2010, European Spine Journal.

[14]  P. Roussouly,et al.  Classification of the Normal Variation in the Sagittal Alignment of the Human Lumbar Spine and Pelvis in the Standing Position , 2005, Spine.

[15]  C. Schmidt,et al.  A barycentremetric study of the sagittal shape of spine and pelvis: The conditions required for an economic standing position , 2006, Annals of Biomedical Engineering.

[16]  E. Berthonnaud,et al.  Sagittal morphology and equilibrium of pelvis and spine , 2002, European Spine Journal.

[17]  C. Poe-Kochert,et al.  Predictive Value of Pelvic Incidence in Progression of Spondylolisthesis , 2003, Spine.

[18]  F. Schwab,et al.  Adult Spinal Deformity—Postoperative Standing Imbalance: How Much Can You Tolerate? An Overview of Key Parameters in Assessing Alignment and Planning Corrective Surgery , 2010, Spine.

[19]  Wafa Skalli,et al.  Differences in Male and Female Spino-Pelvic Alignment in Asymptomatic Young Adults: A Three-Dimensional Analysis Using Upright Low-Dose Digital Biplanar X-rays , 2009, Spine.

[20]  Hubert Labelle,et al.  Spondylolisthesis, Pelvic Incidence, and Spinopelvic Balance: A Correlation Study , 2004, Spine.

[21]  J. Legaye,et al.  Influence of the sagittal anatomy of the pelvis on the intercrestal line position , 2008, European journal of anaesthesiology.

[22]  Paolo Mangione,et al.  Study of the course of the incidence angle during growth , 2005, European Spine Journal.

[23]  Hubert Labelle,et al.  Sagittal Alignment of the Spine and Pelvis During Growth , 2004, Spine.

[24]  J. Hecquet,et al.  Pelvic incidence: a fundamental pelvic parameter for three-dimensional regulation of spinal sagittal curves , 1998, European Spine Journal.

[25]  C. Edwards,et al.  Radiographic Markers in Spondyloptosis: Implications for Spondylolisthesis Progression , 2002, Spine.

[26]  Nathan Peled,et al.  Sacral Orientation Revisited , 2007, Spine.

[27]  T. Beeker,et al.  Toward Standards for Posture: Postural Characteristics of the Lower Back System in Normal and Pathologic Conditions , 1985, Spine.

[28]  J. Pélissier,et al.  Anatomical reliability of two fundamental radiological and clinical pelvic parameters: incidence and thickness , 2005, European Journal of Orthopaedic Surgery & Traumatology.

[29]  Wafa Skalli,et al.  Radiographic analysis of the sagittal alignment and balance of the spine in asymptomatic subjects. , 2005, The Journal of bone and joint surgery. American volume.

[30]  R. Betz,et al.  Sagittal spinopelvic balance in normal children and adolescents , 2007, European Spine Journal.

[31]  Wafa Skalli,et al.  Standing Balance and Sagittal Plane Spinal Deformity: Analysis of Spinopelvic and Gravity Line Parameters , 2008, Spine.

[32]  H. Labelle,et al.  The Importance of Spino-Pelvic Balance in L5–S1 Developmental Spondylolisthesis: A Review of Pertinent Radiologic Measurements , 2005, Spine.