Journal of Neurosurgery: Spine, Jan 2010, Vol. 12, No. 1, Pages 47-55

Sagittal whole-spine magnetic resonance imaging in 750 consecutive outpatients: accurate determination of the number of lumbar vertebral bodies

Eric H. Hanson, M.D., M.P.H.1,2,3, Rahul K. Mishra, D.O.4, David S. Chang2, Thomas G. Perkins, Ph.D.5, Daniel R. Bonifield, D.O.2, Richard D. Tandy, Ph.D.6, Peter E. Cartwright1, Randal R. Peoples, M.D., M.S.2,7, and William W. Orrison Jr., M.D., M.B.A.1,2,3,8,9. 1Advanced Medical Imaging and Genetics (Amigenics), Inc.; 3Departments of Health Physics, Diagnostic Sciences, and 6Kinesiology, University of Nevada Las Vegas; 8Catholic Healthcare West—Nevada Imaging Company; 9University of Nevada School of Medicine, Las Vegas; 2Touro University Nevada, College of Osteopathic Medicine; 7Las Vegas Neurosurgery & SpineCare, Henderson, Nevada; 4Department of Anesthesiology, Texas Tech University Health Sciences Center, Lubbock, Texas and 5Philips Healthcare, Cleveland, Ohio. ©1944-2010 by the American Association of Neurosurgeons.

Abbreviations used in this paper: LSTV = lumbosacral transitional vertebra; VB = vertebral body.

Object
When the number of lumbar and sacral vertebrae is being assessed, variations from typical lumbosacral anatomy may confuse the practitioner, potentially leading to significant clinical errors. In this study, the authors describe the statistical variation in lumbar spine anatomy in an outpatient imaging setting, evaluate the potential implications for clinical practice based on the variation in the number of lumbar-type vertebrae identified, and recommend a method for rapidly determining the number of lumbar spine vertebral bodies (VBs) in outpatients referred for lumbar spine MR imaging.

Methods
A total of 762 patients (male and female) who presented with low back–related medical conditions underwent whole-spine MR imaging in an outpatient setting.

Results
The high-speed whole-spine evaluation was successful for determining the number of lumbar-type VBs in 750 (98%) of 762 consecutive patients. The sagittal whole-spine 3-T MR imaging system images obtained between the beginning of January 2005 and the end of February 2007 were reviewed. The VBs were counted successively from the level of C-2 inferiorly to the intervertebral disc below the most inferior lumbar-type VB. Numbers of disc herniations were also evaluated in the context of the number of VBs.

Conclusions
One in 5 of these outpatients did not have 5 lumbar-type vertebrae: 14.5% had 6; 5.3% had 4; and 1 (0.13%) had the rare finding of 3 lumbar-type vertebrae. Two-thirds of the individuals with 6 lumbar-type vertebrae were male and two-thirds of the individuals with 4 lumbar-type vertebrae were female. Sagittal whole-spine MR imaging can be performed rapidly and efficiently in the majority of patients (98%), and provides improved accuracy for the determination of the number of lumbar-type VBs. A supplementary coronal MR, Ferguson view radiograph or intraoperative fluoroscopic determination for the presence of lumbosacral transitional vertebrae may add additional information when indicated for clinical treatment or surgical planning.

whole-spine MR imaging; lumbar-type vertebra; presurgical planning; vertebral number; vertebral bod.