BACKGROUND: Insufficient attention has been paid to the analysis of the use of instrumental methods of examination in assessment the long-term results of surgical treatment of spondylolisthesis in middle-aged and elderly patients. AIM: To show the peculiarities of strength characteristics of lower limb muscles and temperature and pain sensitivity in the dermatomes of the cauda equina roots in middle-aged and elderly patients in the distant terms after surgical treatment of spondylolisthesis depending on the etiology of the disease. MATERIALS AND METHODS: An analysis of the results of functional studies of 21 patients with spondylolisthesis aged 41 to 74 years (12 with degenerative, 9 with isthmic) is presented. The research done before treatment and 7599 months after surgery. The following research methods were used: analysis clinical (neurological status), visual analog scale (VAS), Oswestry Disability Index (ODI), radiology (functional X-ray examination), magnetic resonance imaging, anthropometry, the lower limb muscles dynamometry, esthesiometry, statistical. RESULTS: In the long term after surgical treatment, patients with isthmic spondylolisthesis had a predominant increase in the moment of force in all muscle groups (3975% of cases). Negative dynamics prevailed in the group of patients with degenerative spondylolisthesis a decrease in muscle strength characteristics in 5094% of cases. According to esthesiometry, more pronounced negative changes in the values of temperature and pain sensitivity thresholds were observed in patients with degenerative spondylolisthesis. CONCLUSION: The analysis of muscle strength characteristics and esthesiometry data determined a different degree of compensation and recovery during surgical treatment of patients with spondylolisthesis, depending on the etiology of the disease.