Biomechanical Research And Clinical Application Of Coflex ^TM Lumbar Interspinous Dynamic Stabilize System

Objective: To discuss the effects of the single coflex^TM system on stability of the operative and adjacent segments of lumbar spine under 3D motions, displacement and rigidity.Methods: The ranges of the motion of 5 fresh adult human cadaveric lumbar spine specimens (L3～S2) were biomechanically tested for forward flexion/extention stretch, left/right lateral bending and left/right axial rotation. The range of motion (ROM), displacement and rigidity of segment L3/4, L4/5, L5S1 were measured and compared at five conditions: A: intact; B: partial destabilization; C: stabilization with the coflex^TM system; D: total destabilization; E: stabilization with pedicle screws and rods.Result: The ROM and displacement of the operative and adjacent segments for C were lesser than that of A, and the rigidity were increased during forward flexion/extention stretch, left/right lateral bending and left/right axial rotation (P<0.05); while there is no influence compared with C and A (P<0.05). The ROM and displacement of the operative segment for E were lesser than that of C and A, and the rigidity were increased sharply during the six different physiological motions (P<0.05); while the ROM and displacement of the adjacent segments for E were larger than that of C and A, and the rigidity were decreased sharply (P<0.05).Conclusions: It can offer non-rigid fixation and control the abnormity of ROM, while it can return a destabilized specimen back to the intact condition in using of the coflex^TM system. Because there is no influence in the adjacent segments compared with strong fixation, it can prevent the degeneration of the adjacent segments.[Objuctive] To assess the clinical effect of the coflex^TM system on the treatment of lumbar degenerative diseases.[Methods] From october 2007 to october 2009, 61 patients who suffered from lumbar degenerative diseases were treated with coflex^TM system.31 males and 30 females with an average of 49.4 years (range, 27 to 74 years) were entered into this study. 63 CoflexTM were implanted, the operated level at L2/3 were 2 cases, L3/4 were 1 cases, L4/5 were 45 cases, L5/S1 were 8 cases, L2/3 L3/4 were 2 cases and 3 cases were Toping-off. The VAS scores, ODI scores and JOA questionnaires were assessed the patients'pain and function while the degrees of satisfaction were assessed the clinical effect. The imaging measurement include the height of intervertebral space, the height of intervertebral foramen, the operative segment movement and the adjacent segment movement on the X-rays examination, CT and MRI were taken if it was necessary.[Results] 53 patients were followed up for an average of 11.5±2.3 months. The VAS scores, ODI scores and JOA questionnaires were changed sharply (respectively 7.79±1.08, 58.49±9.40% and 9.11±1.74 before the operation to 3.70±0.75, 23.44±5.02% and 24.28±2.15 after the operation, P<0.05). The height of intervertebral space and intervertebral foramen changed obviously (respectively 11.37±2.21mm and 22.13±3.60mm to 12.18±2.26mm and 23.92±3.85mm, P<0.05). The operative segment movement were changed obviously (from 8.94±0.67°to 6.87±0.45°, P<0.05), while the adjacent segment movement were almost not changed (from 9.81±3.46°to 10.45±3.08°, P=0.1072). 3 patients had reliquus lumbago, leg pain and 1 patient had reliquus lower extremity numbness. [Conclution] It shows a good clinical effect and is available to restore the height of intervertebral space and intervertebral foramen in using of the coflex^TM system.Meanwhile it has little effect in the adjacent segment movement.However, it must be a long-term follow-up to assess the long-term clinical effect.Objective: Clinical comparative study of the coflex^TM system and PLIF on the treatment of lumbar degenerative diseases.Methods: From october 2007 to october 2009, 95 patients who suffered from single lumbar degenerative diseases (L45) were treated with the coflex^TM system and PLIF. Coflex group:45 patients, 22 males and 23 females with an average of 49.5 years (range, 29 to 70 years); PLIF group:50 patients, 24 males and 26 females with an average of 50.4 years (range, 31 to 75 years)The VAS scores, ODI scores and JOA questionnaires were assessed the patients'pain and function while the degrees of satisfaction were assessed the clinical effect. The imaging measurement include the height of intervertebral space, the height of intervertebral foramen, the operative segment movement and the adjacent segment movement on the X-rays examination.Result: Coflex group: 42 patients were followed up for an average of 12.3±2.1 months, and the average stay were 12.8±1.3 days, the average operative time were 66.8±4.8 minutes, the average intraoperative blood volume was 78.9±7.4ml. PLIF group: 46 patients were followed up for an average of 12.1±1.9 months, and the average stay were 14.6±1.7 days, the average operative time were 117.8±7.2 minutes, the average intraoperative blood volume was 134.2±11.3ml. Both the two groups showed good clinical outcomes by VAS scores, ODI scores and JOA questionnaires, and we found no statistical significance between them both pre-operatively and post-operatively (P>0.05). Both pre- operatively and post-operatively there was no difference between the two groups concerning the height of intervertebral space too (P>0.05). Pre-operatively there was no difference between the two groups concerning range of motions at the operative segment and the adjacent ones (P>0.05). Post-operatively the ROM of the operative segment and the adjacent ones were changed sharply and we found statistical significance between them (P<0.05). We found 2 patients had reliquus lumbago,leg pain and 1 patient had reliquus lower extremity numbness, while 3 patients had reliquus lumbago, leg pain.Conclusions: The non-fusion dynamic stabilize technique can make the same clinical effect compared with the fusion, while it has lower injury and lower complication. Because it can make the adjacent segment lower stress force, coflex can decrease the degeneration of the adjacent one, and it can take the place of PLIF on the treatment of light lumbar degenerative diseases.