Abstract: [Objective] To investigate the short-term efficacy of percutaneous endoscopic transforaminal bilateral lumbar interbody fusion (PE-TIL) for severe central lumbar spinal stenosis (LSS) and its effect on multifidus muscle. Methods The clinical data of 82 patients with severe central LSS were retrospectively analyzed. 38 patients with bilateral decompression via unilateral approach as group U, 44 patients with bilateral decompression via bilateral approaches as group B.The operation conditions of the two groups were compared, the serum creatine kinase (CK) level was measured, the visual analog scale (VAS) score of low back and leg pain, the Oswestry dysfunction index (ODI), the dural sac cross-sectional area(DCSA), multifidus cross-sectional area (MCSA) were detected before and after surgery. Results The serum CK level in group U was lower than that in group B at 1d, 3d and 7d after surgery (P<0.05). At 3 months postoperatively and at the last follow-up, the VAS score and ODI in group U were significantly lower than the group B (P<0.05). At the last follow-up, the MCSA of group U was higher than the group B (P<0.05), but the difference in DCSA between the groups was not significant (P>0.05). The incidence of FBSS in group U was lower than that in group B, and the excellent and good rate of MacNab was significantly higher than that in group B (P<0.05). Conclusion The bilateral decompression via unilateral or bilateral approach in PE-TLIF are safe and effective for the treatment of severe central LSS, while the bilateral decompression via unilateral approach has less damage to the multifidus muscle and can get more ideal postoperative pain symptom improvement.