PURPOSE OF THE STUDY Motion-preservation technologies for spinal disorders have evolved and come into use in the last decade. Three principal systems are currently available: total disc replacement, posterior neutralisation transpedicular system and interspinous implants. The aim of this retrospective study was to evaluate our group of lumbar total disc replacements at a follow-up of 2 years. MATERIAL AND METHODS A total of 42 disc prostheses were implanted in 37 patients. Of these, 31 with 35 artificial discs were followed up for 2 years. There were 11 men and 20 women with an average age of 42.9 years (range, 21 to 61 years). The indication for surgery was lumbar disc pain without radicular syndrome and contraindications included advanced degenerative facet joint disease and obesity with a body mass index over 30. Surgery was carried out through the pararectal retroperitoneal approach. Early and late complications were recorded. The group evaluation was based on radiological outcomes, and VAS and ODI scores reported by the patients at 6 weeks, and 3, 6, 12 and 24 months after surgery. RESULTS The average operative time was 68 minutes (range, 36 to 120 min) for single-level lumbar total disc replacement and 92 minutes (range, 72 to 130 min) for two-level procedures. The average hospital stay was 5.2 days (range, 3 to 12). Both keels of the prosthesis were in the exact center in 25 cases, they were shifted laterally in nine cases up to 2 mm and in one case more than 2 mm. Horizontal rotation of the prosthesis was seen in two patients, but not more than 5 degrees to the left. There was no disc loosening or subsidence, and no acceleration of adjacent segment degeneration. Two patients showed heterotopic ossification. Subjective evaluation was recorded as marked improvement in 15, partial improvement in 11 and no change in five patients. None of the patients reported deterioration. Low back pain assessed by the VAS score had an average value of 66.3 before surgery and 14.1 at 2 years after surgery. The average pre-operative ODI value was 48.9 and that at 2 years post-operatively was 24.5. DISCUSSION Pain relief evaluated by the VAS score in our study is comparable with or slightly better than is reported by the other authors. Some recorded average values for lumbago were 74 before surgery and 35 at 2 years of follow-up, or 62.3 before and 25.4 at 2 years after surgery, while our patients had the average VAS score of 66.3 before surgery and that of 18.4 at 2 years after surgery. The ODI values in our group were similar to those of other authors. When we compare this group with the group of our patients who were treated by spinal fusion surgery, the outcomes at 1 year are better in the total disc replacement group, as shown by the VAS for lumbago of 17.8 and ODI of 24.5 in the former versus the respective values of 18.1 and 29.0 in the latter group. CONCLUSION Based on the results it can be concluded that total disc replacement is an efficient method of treating degenerative inter-vertebral disc disease of the lumbar spine in young, active and motivated patients with no posterior spinal structure degeneration.

Klinika ortopedie a traumatologie pohybového ústrojí FN a LF UK Plzeň

Lumbar total disc replacement. Short-term results

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