Measurement of Lumbosacral Angle in Normal Radiographs: A Retrospective Study in Southeast Nigeria

BACKGROUND: A retrospective study of lumbosacral angle (LSA) in normal lateral supine lumbosacral radiographs of 274 Nigerians (aged 15-74 years) of Southeast region. A supine lateral lumbar spine radiograph is a very accurate means of measuring lordotic angles. The LSA is one of such angles, and can be used in the investigation, treatment and follow-up of low back disorders. Little is known about what the normal value for our population is and therefore, what constitutes hypo-/hyper-lordosis; most of the data in use in medical practice are based on studies on other races. AIM: To quantify the normal LSA in our population. MATERIALS AND METHODS: LSA was measured by the Ferguson's technique and the data analyzed with SPSS Statistics version 17.0 (Chicago IL, USA). RESULTS: LSA varied between 18° and 71°. With a 95.0 confidence interval of 43.3-45.6°, the mean (standard deviation) was 44.5 (9.9)° and showed no significant variation with sex and between various age groups; it compared favorably (though with small difference) with some of the literature values currently in use. CONCLUSION: This study had established the normal lordosis and the possible values at which to consider hypo-lordosis (below 15°), and hyper-lordosis (above 75°) in our population. Also established is that the development of lumbar lordosis ceases at spinal maturity, and that in normal lumbar lordosis measurement, the retrospective approach is a credible alternative to the prospective method.