Improvement in Disc Height after Lumbar Arthroplasty with Mobidisc and Minimum 3 Years of Follow-Up

Degenerative disc disease (DDD) is one of the most common reasons for low back pain in active population. During process of degeneration disc loose water content that leads diminishing of disc height. Disc degeneration is characterized by loosening of water content. These leads to diminishing of disc height, higher stress to facet joints and narrowing neural foramina. The aim of this study is to evaluate improvement in disc height after total lumbar arthroplasty at L4–L5 and L5–S1 segments with a Mobidisc prosthesis.Patients and Methods We analyzed 63 patients in which Mobidisc lumbar prosthesis were implanted at L4–L5 and L5–S1 segments during period of January 2008 to January 2011 in Civil Hospital in Strasbourg, France. Full standing X-rays have been done preoperatively and postoperatively after 6 weeks, 3, 6, 12, and 36 months. X-rays were digitalized and measurement were performed by using Spineview software. Measurement was statistically significance at p < 0.05.Results The mean follow-up was 44 months; 45 females and 18 males were analyzed with average 41.3 year of age. Prosthesis was implanted at L4–L5 in 19 cases and at L5–S1 in 44 cases. Preoperative anterior disc height at L4–L5 was significantly improved, from 6.30 to 9.03 mm (2.73 mm) postoperatively ( p < 0.01). Posterior disc height at same level was also improved, from 2.82 mm preoperatively to 3.90 mm postoperatively (1.08 mm) ( p < 0.05). At level L5–S1 anterior and posterior disc height were improved as well. From 4.99 mm to 7.53 mm (2.54 mm) ( p < 0.05) and from 2.52 mm to 4.66 mm (2.14 mm), respectively, ( p < 0.05).Conclusion During lumbar disc arthroplasty the size of prosthesis may have a significant role in a final postoperative result. Oversize prosthesis may produce too much distraction to posterior ligaments and muscles of lumbar spine. On the other hand, too small implants will not reduce stress enough on facet joints nor will adequately open neural foramina. In both cases, this would probably result in painful syndromes of lumbar spine.