Hamid Rezaee - Department of Neurosurgery, Mashhad University of Medical Sciences, Mashhad, Iran
Gholamreza Bahadorkhan - Department of Neurosurgery, Mashhad University of Medical Sciences, Mashhad, Iran
Mohammadreza Ehsaei - Department of Neurosurgery, Mashhad University of Medical Sciences, Mashhad, Iran
Babak Ganjeifar - Department of Neurosurgery, Mashhad University of Medical Sciences, Mashhad, Iran
Ehsan Keykhosravi - Department of Neurosurgery, Mashhad University of Medical Sciences, Mashhad, Iran
Masoud Pishjoo - Department of Neurosurgery, Mashhad University of Medical Sciences, Mashhad, Iran

Background: Recently, in approach to spinal pathologies, the whole spine should be considered as a biomechanicalunit. Studies have shown the great importance of sagittal and coronal balance and the relationship between the variousparts of spine together and pelvis. Former studies have shown a close relationship between spinopelvic parametersand sagittal balance. A complete understanding of sagittal balance basics is needed to achieve the best outcomeand avoiding future complications after treatment of spinal deformities. In this study, the normal range of spinopelvicparameters among healthy volunteers in Iran has been evaluated.Methods: This cross-sectional study was conducted on healthy volunteers in 2017. The lateral whole-spine X-ray wasobtained under the standard conditions. Two spine surgeons measured the parameters including pelvic incidence,pelvic tilt, sacral slope and lumbar lordosis.Results: In this study 100 volunteers were studied; out of whom, 41 participants were male and the mean age was47.5±11.7 years. The average pelvic incidence, pelvic tilt, and sacral slope were 51.5±10.9, 17.4±9.9, and 34.8±8.8degrees, respectively. The pelvic tilt was significantly lower in women. It was found that with increasing age, the pelvicincidence and pelvic tilt increases while lumbar lordosis decreases (p <0.05).Conclusion: This study is the first study on the normal range of spinopelvic parameters in healthy individuals in Iran..Our data showed that PT and PI-LL are significantly lower in women, while, PT, PI and PI-LL increase and LL decreasesin older ages.Level of evidence: II

healthy people, Normal range, Parameter, Sagittal balance, Spinopelvic