Comparative Cohort Study Of Paraspinal Muscle Volume Change Between Uniportal Full Endoscopic And Minimamally Invasive Open Posterolateral Transforaminal Lumbar Interbody Fusion

Abstract Background Recent literature of uniportal full endoscopic posterolateral transforaminal lumbar interbody fusion demonstrates good clinical and radiological outcomes with minimally invasive benefits potentially preserving paraspinal muscle. There is no literature on paraspinal muscle volume change between the endoscopic and microscopic minimally invasive interbody fusion.Methods We included patients who met the indication criteria for lumbar fusion and underwent either uniportal full endoscopic posterolateral transforaminal lumbar interbody fusion or open transforaminal lumbar interbody fusion. Clinical parameters of visual analog scale and Oswestry disability index were measured at preoperative, postoperative 1 week, 3 months postoperative and final follow up. Magnetic Resonance Imaging measurement of preoperative and postoperative Kjaer grade, right and left psoas muscle mass area, right and left paraspinal muscle mass area were performed.Results 74 levels of Endo-TLIF and 42 patients with minimally invasive Open TLIF were included. There was statistically significant greater improvement in VAS and ODI in Endo-TLIF cohort at 1 week significant improvement of Kjaer grade at postoperative 1 year in Endo-TLIF compared to MIS-TLIF. There is statistically significant improvement in paraspinal muscle mass area in Endo-TLIF (104.83 ± 316.45) mm2 compared to MIS-TLIF (89.88 ± 185.14) mm2Conclusion Uniportal Endoscopic Posterolateral Lumbar Transforaminal Interbody Fusion achieved improved paraspinal and psoas muscle bulk and less fatty infiltration in the operated level as compared to Minimally Invasive Open Transforaminal Lumbar Interbody Fusion while both cohorts achieved equivalent positive clinical outcomes.