Objective. To evaluate the long-term results of surgical treatment of patients with monosegmental stenosis of the lumbar spine after using minimally invasive and standard open techniques.Material and Methods. The open cohort randomized prospective study included 132 patients. Long-term results were assessed in 110 patients, some patients discontinued participation in the study for natural reasons. Patients were operated on in 200–2011 in the volume of minimally invasive decompression and stabilization surgery (Group 1) and decompression and stabilization surgery through conventional posteromedial approach (Group 2). The following parameters were analyzed: Oswestry Disability Index and VAS pain intensity. Formation of an interbody block was assessed using the Tan scale, and the fatty degeneration of the paravertebral muscles – according to the Goutallier scale. Development or aggravation of the course of degeneration of the adjacent segment was also evaluated. Statistical analysis was performed using the R packages for data processing and plotting.Results. At long-term follow-up (144 months), when assessing back pain according to VAS and ODI, a statistically significant difference p < 0.001 in favor of minimally invasive interventions was revealed. Both surgical methods resulted in high rates of fusion and low reoperation rates. In the group of minimally invasive surgical interventions, there is a lower incidence of fatty degeneration of the paravertebral muscles and damage to the adjacent segment.Conclusions. Open and minimally invasive surgical interventions have comparable long-term clinical and morphological results. Open surgical interventions in the long term are fraught with aggravation of fatty degeneration of the paravertebral muscles and more frequent development of the adjacent level syndrome. Minimally invasive techniques are an effective and safe alternative to traditional open surgery and can reduce trauma, preserve the intact posterior support complex of the spine at adjacent levels, while performing adequate decompression and stabilization, followed by the formation of a bone block.