Introduction. Lumbar disc disease is the most frequent reason of low back pain in adult population. Most cases of this disease can be treat conservatively. If conservative therapy Is unsuccessful within 6 to 12 weeks operative treatment should be considered. Interspinous decompression is less invasive, safe procedure for treating: disc hernia, degenerative disc disease and spinal stenosis. The main goal of this procedure is to unload the posterior annulus and consequently reduce pain. Objective. The objective of this study Is clinical and radiological assessment of treating symptomatic lumbar disc disease with inSwing interspinous spacer. Material and Methods. The study included 51 of 150 patients operated between February 2005 and December 2008. Average follow-up after surgery was 22 ( 12 - 37) months . Mean age at the day of surgery was 37 (18-60) years. Saggital scans of T2 sequence of MRI performed before and 6 months after the surgery were compared. Intervertebral angle of operated segment, total lumbar lordosis and 1/3 posterior disc height were compared: before operation, 3 and 12 months after operation. In the same intervals clinical outcomes using the Visual Analog Scale (separately for back and leg), the Oswestry Disability Index. Results. Disc bulge decreased average 33% in 6 months after surgery, hydratation of disk on operated segment improved in 30% patients. Postoperatively, there were significant changes in the angle of operated segment (from average 9,35 to 5,42 degrees), the 1/3 posterior disc height (from average 9,61 to 10,03 mm).The average VAS for back pain dropped from 8,3 to 3,7 and the average VAS for leg pain dropped from 6,0 to 2,5. The average Oswestry Disability Index dropped from 65% to 36%.