Undergraduate Student University of Wisconsin - Madison, United States
Introduction: There is a substantial discrepancy in the utilisation of spinal endoscopy between East Asian countries and the USA, with endoscopy being significantly more common in Asia to perform lumbar discectomies. We hypothesize that these general variances in endoscopy use between these regions may be, in part, due to fundamental differences in the lumbar intervertebral disc morphology between these two patient populations. Significant variation in morphology may contribute to the efficacy of spinal endoscopy practice and have implications for the development of related tools and techniques worldwide.
Methods: A retrospective review of prospectively collected data for consecutive patients undergoing microsurgical or endoscopic discectomy for herniated lumbar intervertebral discs in two centers in the USA and two centers in China. Variables included: age, sex, lumbar lordosis angle (L1-S1), intervertebral disc height in the mid-sagittal plane (L1-S1). Analysis included Fisher Exact Test for categorical variables and T-Test with correction for multiple comparisons for continuous variables.
Results: Between the sites enrolled in the study there were 116 patients from the USA and 30 from China. USA patients were significantly older (58.718.5 vs 42.513.5, p< 0.001) but there were no differences in sex (female: 43.9% vs. 56.7%, p=0.23). Lumbar lordosis was significantly higher in the USA cohort (39.89.2 vs. 33.016.7, p=0.018). The intervertebral disc heights in millimeters were significantly taller for the Chinese cohort at all levels except the L5-S1 disc (L1-2: 9.11.9 vs. 10.01.7, p=0.005; L2-3: 9.82.2 vs. 11.61.9, p< 0.0001; L3-4: 10.42.5 vs. 12.52.4, p< 0.0001; L4-5: 10.32.3 vs. 13.12.6, p< 0.0001; L5-S1: 10.42.4 vs. 10.91.9, p=0.067).
Conclusion : Patients in a Chinese cohort undergoing lumbar discectomy had significantly taller lumbar intervertebral disc heights and less lumbar lordosis than a cohort of patients from the USA. These differences in the intervertebral disc height may be a factor contributing to higher rates of spinal endoscopy in Asia compared to the USA as taller disc heights allow for technically easier endoscopic access to the disc space during surgery.
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