The paper presents the results of spinal dysfunction treatment using interspinous stabilizer according to the method interS/inSWing. Clinical material included 3-years clinical observations. Stabilizer was used on one or two levels and the stabilized segment was L4/L5 and L5/S1. Very good clinical results were obtained and the importance of enlarged preoperative diagnosis was demonstrated. In parallel the importance of implant size selecting to intervertebral space geometry has been demonstrated, which is also presented in biomechanical studies.