Combining the percutaneous transforaminal endoscopic decompression (PTED) with interspinous process distraction systems (ISP) may offer additional benefits in treating spinal stenosis in patients who have failed conservative treatment. We retrospectively investigated the medical records of 152 patients who underwent transforaminal endoscopic decompression with simultaneous ISP placement through the same incision. Patients were operated on from January 2008 to June 2016 and included 80 males, and 72 patients were females. Clinical data analysis was done on 142 patients two years postoperatively since ten patients were lost in follow-up. Primary outcome measures were pre-and postoperative visual analog scale (VAS) criteria and the Oswestry Disability Index. Only patients with a minimum follow-up of 2 years were included. The analysis included 224 patients who underwent interspinous spacers during the transforaminal endoscopic decompression. Of the 152 patients, 84 complained of axial facet-related pain syndromes versus the remaining 68 patients who chiefly complained of radicular symptoms. The postoperative VAS reduction at twoyear follow-up for the low back was 6.4. The patient-reported ODI reductions were of a similar magnitude at 40.4%. According to Macnab criteria, the percentage of patients who graded their surgical results as excellent or good was 90%. At two-year follow-up, 5 percent of patients required another operation to deal with failure to cure or recurrent symptoms due to implant subsidence. The authors concluded that adding an interspinous process spacer to the endoscopic decompression in patients treated for lateral lumbar stenosis and foraminal stenosis with low-grade spondylolisthesis might improve clinical outcomes by stabilizing the posterior column.