INTERSPINOUS STABILIZATION-FUSION IN THE UNSTABLE SPINE.

Transcription

1 INTERSPINOUS STABILIZATION-FUSION IN THE UNSTABLE SPINE. A PRELIMINARY REPORT F. POSTACCHINI, A. PALMESI

2 LUMBAR VERTEBRAL INSTABILITY Still the subject of discussion Variously defined and interpreted

3 Postacchini in 1992 distinguished three types of clinical instability Potential instability Actual instability Microinstability

4 Potential instability Condition in which the motion segment is predisposed to instability and may become unstable as a result of degenerative changes, or increase in degenerative changes, of the motion segment or compromise of its stabilizing structures (such as the intervertebral disc and facet joints)

5 Actual instability Condition in which the motion segment is presently unstable, the instability being demonstrated by imaging studies showing vertebral hypermobility (such as flexion/extension radiographs)

6 MICROINSTABILTY OCCULT INSTABILITY Minor instability of the motion segment, responsible for posture-related low back pain, in the absence of radiographic evidence of vertebral hypermobility Discogenic low back pain Post-discectomy low back pain unloaded under load Condition difficult to demonstrate and label often used improperly

7 Common degenerative disc disease May it be considered a condition of vertebral instability? NO

8 Our experience with Aspen started in patients with degen. disc disease with no evidence of instability In most cases the results were satisfactory

9 RATIONALE Rigid stabilization exposes to the risk of subsequent disc degeneration at adjacent levels 40 y Instr. PLIF L degen. disc desease L3-4 not present in 2003 Interspine spacer 3 4

10 Similar effects can be observed also in elderly patients with vertebral instability Paz. 62 a y. Instrum. PLIF L stenosis L3-4 Bilateral laminectomy & posterolateral fusion

11 CIRCONFERENTIAL FUSIONS ARE NECESSARY OR ALWAYS NECESSARY? HOW OFTEN THEY PRODUCE SECONDARY EFFECTS? DO WE HAVE TO FIND NEW SOLUTIONS?

12 Spondylo L4 Lat. stenosis L4-L5 Percutan. pedicle-screw instrumentation Bilateral decompression by unilateral approach Interspinous stabiliz.-fusion Preoperatorio FUSION 12 months postop. Fx Ex GOOD RESULT

13 SD L4 & stenosis L4-L5 Percutaneous pedicle-screw instrumentation Bilaterasl decompression by unilateral approach postoperatorio NO FUSION 16 months postop. Interspinous stabiliz.-fusion Fx Fx Ex EXCELLENT RESULT

14 76 years, osteoporosis Stenosis and spondylo L4 Bilateral decompression by unilateral approach Instrumentation-PL fusion unilateral left (unstable screws on right side) Persistent low back pain Persistent, severe LBP Functional x-rays: mild hypermob. L4 Posterolateral fusion right Interspinous stabilz-fusion FUSION Disappearance back pain 2 weeks after reoperation

15 3 4 NO FUSION SD & severe stenosis L4-L5 Percutaneous ped.-scew instr. FAIR RESULT Bilat. decomp. unilat. approach & interspinous stabiliz-fusion L3-5

16 Fx SD L4, stenosis L4-L5 Mild hypermobility in F-E Bilateral decompression by unilateral approach & interspinous stabiliz.-fusion GOOD RESULT NO FUSION 4 Ex

17 Removal of ASPEN in 2 cases After 6 months Persistence of LBP during rotational movements

18 OUR SERIES 12 cases of potential or 7 females and 5 males with a mean age of 61 y All with degenerative spondylolisthesis of L4 Aspen at single level in 10 cases and 2 levels in 2 Interspinous autologous bone fusion in 5 cases

19 CLINICAL RESULTS patients

20 Satisfactory results - 8 patients Interspinous bone fusion - 5 patients

21 CONCLUSIONS 1) Our experience with Aspen in the unstable spine is still very limited and no definite conclusion is allowed 2) 2/3 of our patients had satisfactory results, while 1/3 had postop. back pain 3) The results appear to be better if an interspinous bone fusion is performed 4) The advantages of Aspen compared to posterolateral or interbody fusion are that A) the rigidity of the motion segment is lesser, B) the operative time is lower, C) the complication rate appears to be significantly lower, and D) in case of failure the implant can be removed and fusion performed 5) The disadvantage is that a part of patients have postoperative back pain, the cause of which is sometimes unclear 6) A larger experience is needed to determine IF and WHEN the implant should be used in the unstable spine

22 GRAZIE