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Introduction to Spine Arthroplasty Ira Fedder, MD Scoliosis and Spine Center Towson, MD DePuy Spine confidential information. Do not duplicate. Do not.

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Presentation on theme: "Introduction to Spine Arthroplasty Ira Fedder, MD Scoliosis and Spine Center Towson, MD DePuy Spine confidential information. Do not duplicate. Do not."— Presentation transcript:

1 Introduction to Spine Arthroplasty Ira Fedder, MD Scoliosis and Spine Center Towson, MD DePuy Spine confidential information. Do not duplicate. Do not distribute.

2 Spine Surgery at the Millennium Posterolateral +/- Instrumentation Posterolateral +/- Instrumentation Circumferential (“360°”) Circumferential (“360°”) PLIF (Posterior Lumbar Interbody Fusion) PLIF (Posterior Lumbar Interbody Fusion) ALIF (Anterior Lumbar Interbody Fusion) ALIF (Anterior Lumbar Interbody Fusion) TLIF (Transforaminal Lumbar Interbody Fusion) TLIF (Transforaminal Lumbar Interbody Fusion)

3 Paradox Can the same problem (discogenic pain) be treated effectively using interventions with the exact opposite technical goals?

4 80% Anterior 20% Posterior Biomechanics The 80-20 rule of Spine loading

5 History of Lumbar TDR Fernström – 1960’s

6 History of Lumbar TDR Synthes ™ PRODISC ® I - 1987PRODISC ® II - 1999

7 History of Lumbar TDR Medtronic ™ Maverick ™ - 2001

8 Karin Büttner-Janz INVENTOR History DePuy Spine confidential information. Do not duplicate. Do not distribute.

9 History of Lumbar TDR I - 1984II - 1985 III - 1987 SB CHARITÉ ™

10 History Design Iterations Inventors Drs. Schellnack and Büttner-Janz Inventors Drs. Schellnack and Büttner-Janz SB Charité ™ I SB Charité ™ I 1984 1984 13 patients, 14 Implants 13 patients, 14 Implants SB Charité ™ II SB Charité ™ II 1985 1985 36 patients, 44 Implants 36 patients, 44 Implants Non-forged stainless steel Non-forged stainless steel No special instrumentation No special instrumentation Data from The Artificial Disc, Buttner-Janz, 2003 Experimental Prototypes Never Commercially Available

11 History - Current Design CHARITÉ Artificial Disc Refined design by Waldemar Link Refined design by Waldemar Link Cast Cobalt Chrome Endplates Cast Cobalt Chrome Endplates Ultra High Molecular Weight Polyethylene (UHMWPE) Sliding Core Ultra High Molecular Weight Polyethylene (UHMWPE) Sliding Core Design unchanged since 1987 Design unchanged since 1987 First released 1987 First released 1987 Thousands of implantations worldwide Thousands of implantations worldwide Same design used in U.S. IDE clinical study Same design used in U.S. IDE clinical study 17-year track record 17-year track record

12 Design Rationale Comprised of 3 Components 2 Cobalt Chrome (CoCr) Endplates 2 Cobalt Chrome (CoCr) Endplates 1 UHMWPE Sliding Core 1 UHMWPE Sliding Core Mobile-bearing technology Mobile-bearing technology Convex Sliding-Core Concave Endplates

13 Design Rationale Footprint Sizes 2 3 4 5

14 Design Rationale Lordotic angles 12.5°12.5° 15°15° 17.5°17.5° 20°20° 0°0° 5°5° 7.5° 10° 10°10° 10°+ 0 ° or 5° + 5° 10° + 10° 7.5° + 5° 10° + 7.5° 7.5° + 7.5° or 10° + 5° Combinations Intra-Operative Modularity 0°+ 7.5 ° 7.5°7.5° 5°5° 0°+ 5 ° 0°+ 0 ° 0°0°

15 Design Rationale Sliding Core Heights 7.5 8.5 9.5 10.5 11.5 H H 2.5mm

16 Importance of Sizing Proper Endplate Size Bone Density Dr. Wolfgang Raushning - Uppsala University, Sweden 2000

17 David, TJ. Results related to surgeon experience 1989 - 1991 1989 - 1991 43 patients: 63% excellent/good 43 patients: 63% excellent/good 1992 - 1994 1992 - 1994 57 patients: 82% excellent/good 57 patients: 82% excellent/good 1995 - 1997 1995 - 1997 44 patients: 93% excellent/good 44 patients: 93% excellent/good “Lumbar Disc Prosthesis: Five Years Follow-up Study on 147 Patients with 163 SB Charité Prosthesis.” EuroSpine 2003

18 European Experience: Lessons Learned Sizing Sizing Positioning Positioning Patient selection Patient selection Controlled distraction Controlled distraction

19 Learning Objectives  Patient Selection

20 Radiographic Evaluation We ARE treating discogenic pain with TDR Biggest challenge is to identify the pain generator Biggest challenge is to identify the pain generator Start with plain x-rays, MRI Start with plain x-rays, MRI Studies have shown high false positive rate of MRIs Studies have shown high false positive rate of MRIs Discography can help distinguish between asymptomatic “dark discs” on MRI and those that are pain generators Discography can help distinguish between asymptomatic “dark discs” on MRI and those that are pain generators

21 Discography Clinical pain provocation test Clinical pain provocation test Radiographic images Radiographic images Test is positive only if: Test is positive only if: The disc is abnormal in appearance The disc is abnormal in appearanceAND Patient’s clinical pain is provoked during injection Patient’s clinical pain is provoked during injection

22 Clinical Indications Chronic low back pain +/- leg pain Chronic low back pain +/- leg pain Persisting > 6 months Persisting > 6 months Associated with degenerative disc changes Associated with degenerative disc changes Leg pain Leg pain Radicular Radicular Pseudoradicular Pseudoradicular Foraminal stenosis Foraminal stenosis Secondary to disc space height loss Secondary to disc space height loss may be relieved indirectly by disc height restoration may be relieved indirectly by disc height restoration

23 Contraindications Dexa-scan patients > age 50 or with more than 1 risk factor Dexa-scan patients > age 50 or with more than 1 risk factor T< -1.0 is contraindicated T< -1.0 is contraindicated Osteoporosis or Osteopenia

24 Contraindications Scoliosis >11º sagital deformity

25 Contraindications Instability including isthmic spondylolysis isthmic spondylolysis spondylolisthesis spondylolisthesis retro or anteriolisthesis > 3mm retro or anteriolisthesis > 3mm

26 Contraindications Poor psychometric evaluation  Abnormal pain discogram  Hz of Schizophrenia  Bi-polar condition  Severe depression  Inability to comprehend procedure and risks

27 Facet Disease? Widened joint diagnostic for instability: Degenerative Spondy

28 Facet Disease Contraindication:  Advanced Facet Disease  Severe Spinal Stenosis (canal space < 8mm)  Use CT Myelogram to evaluate Moderate Mild Severe

29 Contraindications Central Stenosis Central Stenosis Tumor Tumor Arachnoiditis Arachnoiditis History of chronic steroid use History of chronic steroid use Advanced facet disease Advanced facet disease Facet joint ankylosis Facet joint ankylosis Metal allergies Metal allergies Pregnancy Single or bilateral leg pain (due to nerve compression) Non-contained herniated nucleus pulposus Infection/neoplasm Autoimmune disorders

30 Approach Related Contraindications Anterior Vascular Calcification Anterior Vascular Calcification Previous major vessel surgery Previous major vessel surgery Obesity: BMI > 40 or 100lbs over ideal body weight Obesity: BMI > 40 or 100lbs over ideal body weight Previous retroperitoneal procedures Previous retroperitoneal procedures

31 Handling Vascular Complications Control: Control: One can often get proximal and distal control with pressure against the spine using peanut or sponge on a stick One can often get proximal and distal control with pressure against the spine using peanut or sponge on a stick Hemoclips: Hemoclips: Use a row of hemoclips along injured edge of vein rather than try to sew in a small deep wound Use a row of hemoclips along injured edge of vein rather than try to sew in a small deep wound Cell Saver: Cell Saver: Typically cell saver is not used routinely unless an injury occurs Typically cell saver is not used routinely unless an injury occurs

32 Spine Surgeons: Tips To Avoid Complications Cut the annulus Cut the annulus Clean side to side Clean side to side Remain in the space Remain in the space Beware of cautery conduction Beware of cautery conduction Be aware of the vessels Be aware of the vessels Always check clearances before using Spreading and Insertion Forceps Always check clearances before using Spreading and Insertion Forceps Lateral clearance Lateral clearance Superior / Inferior clearance Superior / Inferior clearance Maintain vascular clearance Maintain vascular clearance

33 Effectiveness Results (All Randomized) Small P-value indicates high degree of certainty Small P-value indicates high degree of certainty Primary Hypothesis: Overall Success Rate Conclusion: The CHARITÉ Artificial Disc is at least equivalent in overall success to the BAK cage in treatment of DDD at one level (L4-S1).

34 Effectiveness Results (All Randomized) * re-operation, revision, removal or additional fixation ** major vessel injury, neurological damage or nerve root injury Primary Effectiveness Endpoints

35 Implant Lateral X-Ray Final Center of rotation 2mm dorsal sagital midline maximum footprint coverage – proper lordotic angles

36 Implant A/P X-Ray Final Center spike positioned on A/P midline

37 Final Position

38 Final AP & Lateral Position

39


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