Purpose
Definitions:Spondylolysis: defect in the pars interarticularisIsthmic spondylolisthesis: slip of thecranial vertebral body due to spondylolysisClassification: Meyerdinggrade I to V ->slip of 25/50/75/100%Spondylolysis and isthmic spondylolisthesis are common multi-factorial disorders. The extent of the slip of the spondylolytic vertebra is considered a major predicator for prognosis and further follow-up.Vertebral hypoplasia is a common finding in spondylolysis.The purpose of this study is to evaluate the incidence of hypoplastic vertebral bodies in patients with spondylolysis and in the general population and to analyse the impact of the findings...
Methods and Materials
140 patients with 141 levels of spondylolysis or isthmic spondylolisthesis were included in this study presented from March 2006 to May 2009.Asagittal T2 weighted scan in the sitting position was aquired.The images were analysed digitally using a picture archiving and viewing software.After identification of the spondylolysis, the level was noted.If spondylolisthesis was present, the slip of the spondylolytic vertebra was measured as shown in Figure 1. The slip was recorded in millimetres.After that the difference in length between the cranial, spondylolytic vertebra and the adjacent...
Results
140 patients with 141 levels of spondylolysis or isthmic spondylolisthesis were included in this study.The level of spondylolysis was level L5/S1 in 122 cases, L4/5 in 14 cases, L3/4 in 4 cases and L2/3 in one case. The spondylolysis was unilateral in eight cases and bilateral in 133 cases.Spondylolisthesis was diagnosed in 120 patients. The mean range of the slip in the midline sagittal image was 9 mm, with a range of 3 to 17 mm of slip.In 50 patients the vertebral body of the...
Conclusion
A shortening of the spondylolytic vertebra is common and it mimics spondylolisthesis.In 19 patients the hypoplasia was equal to the measured slip. Hence the term ‘spondylolisthesis’ should be reserved for patients with a real difference between a shortened hypoplastic vertebra and a measured slip.The classification of the slip should take note of the hypoplasia.
References
Meyerding HW. Spondylolisthesis. Surg Gynecol Obstet 1932;54:371-377Hu SS, Tribus CB, Diab M, Ghanayem AJ. Spondylolisthesis and spondylolysis. Journal of Bone & Joint Surgery - American Volume 2008;90:656-671Ulmer JL, Mathews VP, Elster AD, Mark LP, Daniels DL, Mueller W. MR imaging of lumbar spondylolysis: the importance of ancillary observations. American Journal of Roentgenology 1997; 169:233-239Ulmer JL, Elster AD, Mathews VP, King JC. Distinction between degenerative and isthmic spondylolisthesis on sagittal MR images: importance of increased anteroposterior diameter of the spinal canal ("wide canal sign"). American Journal...
