BACKGROUND This study aimed to investigate and compare the clinical efficacy of an innovative endoscopic posterior/transforaminal lumbar interbody fusion (Endo-P/TLIF) technique and a minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) technique in the treatment of lumbar spinal stenosis (LSS). METHODS A retrospective analysis was conducted on 45 patients who underwent Endo-P/TLIF (n = 22)(Group A) and MIS-TLIF (n = 23) ༈Group B༉for single-segment LSS between October 2018 and July 2020. The age, sex, and surgical levels between both groups were comparative. Operation time, intraoperative blood loss, wound length, postoperative wound drainage flow, and postoperative time spent bedbound were recorded. Magnetic resonance imaging (MRI) was evaluated preoperatively and 1 year postoperatively to assess the injury of the paravertebral muscles. Visual analog scale (VAS) and Oswestry Disability Index (ODI) scores were evaluated 1 day preoperatively, and at 7 days, 3 months, 6 months, and 1 year postoperatively to compare the clinical efficacy of the two groups. Computed tomography (CT) scans were performed at 6 months postoperatively, and interbody fusion was evaluated using the Bridwell criterion. RESULTS The operation time for group A (158.3 ± 32.5) was longer than that for group B (121.3 ± 27.6, P < 0.05). Intraoperative blood loss, surgical incision length, postoperative drainage volume, and postoperative time spent bedbound for group A were significantly lower than those for group B (P < 0.05). The transversal areas of the paravertebral muscles for group A were significantly larger than those for group B (P < 0.05). VAS and ODI scores for lumbar and leg pain in both groups were significantly decreased after surgery. However, scores in group A were significantly lower than in group B at 1 week and 3 months after surgery (P < 0.05); however, no significant difference was noted in scores at 6 months and 1 year postoperatively. CONCLUSIONS Both techniques have similar efficacy in the treatment of single-segment LSS; however, patients who received Endo-P/TLIF had less postoperative paravertebral muscle injury, reduced low back pain, and a quicker recovery.