Coflex TM for Lumbar Stenosis with Segmental Instability : 1 yr outcomes Eun-Sang Kim, M.D., Ph.D. Clinical Professor Dept of Neurosurgery Samsung Medical Center Seoul, Korea
Surgery for Spinal Stenosis Decompression only Develops instability Stenosis Fusion Adjacent segment failure Degenerative Spondylolisthesis II, III
Fusion with pedicle screws Stabilizing Effect Op time Blood loss Recovery period Adjacent segment disease through excessive stress
Why Interspinous Implants? Op time Blood loss Recovery period Stress on Adjacent segments (?) Stabilizing Effect without heavy metals, nor fusion (?)
Objective of the study Coflex TM (interspinous U ) Can it be an alternative treatment for degenerative lumbar instability?
Hypothesis Implanting Coflex TM would result in Similar clinical outcomes, or It may even prove superior to PLIF w/o affecting degeneration at adjacent segments.
Clinical Material (1) Period: Jan 00 ~ Dec 03 adults (M/F = 11/31) 18 pts: CoflexTM (by Kim) N: 42(M/F = 3/15, 61.7 yrs) 24 pts : PLIF (by Eoh) (M/F = 15/16, 56 yrs)
Clinical Material (2) All pts have Low back pain (LBP) Mechanical With referred pain Intermit neurog claudication Spinal stenosis w/ instability, at L4-5 level
Clinical Material (3) Inclusion Criteria Deg. listhesis, Gr I (18 pts) Translational slip 4 mm Angular instability (14 pts) Intervertebral ROM > 10º Mild retrolisthesis (10 pts)
Clinical Material (4) Exclusion Criteria Pts who have: Marked deg. listhesis > 5 mm Isthmic spondylolisthesis Lesions that need Op 2 levels
Demographics Coflex TM PLIF Pts. No 18 24 male 3 8 female 15 16 Mean age 61.7 56 Spinal stenosis w/ angular instability 7 7 w/ translat slip 4 mm 7 11 w/ retrolisthesis 4 6
Methods (1) PLIF Using cages (e.g., PEEK or CH cages, etc) Additional pedicle screw fixation Autogenous iliac or lamina bone
Coflex TM Usual midline post. approach Skin incision, 4 cm Paravertebral m. dissection Methods (2) cranial caudal
Methods (3) Coflex TM Skin incision, 4 cm PVM dissection Removal of intersp. Ligament Bilat laminotomy Removal of Lig. flavum Dura
Coflex TM Application of template Methods (4)
Coflex TM Methods (5) Application of template Preparation of wingclamps
Coflex TM Application of template Preparation of wing-clamps Interspinous insertion of Coflex TM Methods (6)
Methods (7) Coflex TM Application of template. Preparation of wing-clamps Interspinous insertion of Coflex Wing-clamps tightening
Methods (8) Postop F/U : 1, 3, 6, &12 mos Dynamic/static radiol evaluation Segmental intervertebral angle Posterior disc height
Methods (9) ROM: the sum of intervertebral angle btw flexion & extension per level Flex Ext
Methods (10) Clinical analysis Visual Analogue Scale (VAS) Oswestry Disability Index (ODI) Wilcoxon Signed Ranks t. (SPSSx) Mann-Whitney t. for nonnumerics F/U at OPD after 1, 3, 6,&12 mo
RESULTS
Clinical Outcomes (1) No surgical complications in both PLIF and Coflex TM groups.
Clinical Outcomes (2) VAS ODI
Preop Postop Flex Ext
Preop Postop Flex Ext
Radiologic Outcome Coflex TM PLIF ROM (degree) Preop. Postop. Preop. Postop. L3-4 6.1 (±3.7) 5.7 (±3.8) 7.2 (±4.1) 10.5 * (±5.2) L4-5 10.0(±4.1) 5.1 * (±4.8) 12.7(±3.7) 0. 7 * (±1.5) L5S1 6.6 (±4.8) 5.1 (±4.8) 11.2(±5.8) 10.2 (±7.6) PDH (mm) 7.8 (±1.8) 9.1 * (±2.2) 6.9 (±2.9) 11.2 * (±1.3) Mean value ± standard deviation. * significant statistically PDH: posterior disc height at the L4, 5 level
Illustrative Cases
Case 1. F/ 54 C/C : lower back pain & NIC (5 min)
Operation: Clinical course bilateral PHL with foraminotomy Coflex TM insertion VAS : 6 1 (after 6 months) ODI: 44 26 NIC improved, LBP disappeared L4,5 Flexion Extension ROM Disc ht Preop. -9.4 2.1 11.5 10 Postop. -4.5 3.8 9.3 9.9
Preop Postop Flex Ext
Case 2. F/ 68 C/C : lower back pain & NIC (10 min)
Preop Postop Flex Flex Ext Ext
Operation: Clinical course bilateral PHL with foraminotomy Coflex TM insertion VAS : 8 ODI : 46 25 3 (after 5 months) NIC improved, LBP decreased L4,5 Flexion Extension ROM Disc ht Preop. 5.8 15 9.2 7.6 Postop. 8.9 10.8 6.1 7.2
Case 3. F/ 64 C/C : LBP, NIC (200 m), Urinary incontinence
Preop Preop Postop 6 mo
Preop Postop Flex Flex Ext Ext
Operation: Clinical course bilateral PHL with foraminotomy interspinous U insertion VAS : 9 ODI : 48 24 2 (after 6 months) NIC improved, LBP decreased L4,5 Flexion Extension ROM Disc ht Preop. 3.8 9.3 5.5 7.1 Postop. 3.8 7.8 4.0 8.6
Summary Coflex TM Insertion at L4-5 ROM at the instrumented level No ROM change at the upper adjacent motion segment (c.f. PLIF) Mechanical LBP in lumbar stenosis with instability
Conclusion Coflex TM implantation can be an alternative treatment for spinal stenosis with minor segmental instability since it imparts less stress on the superior adjacent level than PLIF does.