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DePuy Spine confidential information. Do not duplicate

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Presentation on theme: "DePuy Spine confidential information. Do not duplicate"— 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 Circumferential (“360°”) PLIF (Posterior Lumbar Interbody Fusion) ALIF (Anterior 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 rule of Spine loading

5 History of Lumbar TDR Fernström – 1960’s

6 History of Lumbar TDR Synthes™ PRODISC® I PRODISC® II

7 History of Lumbar TDR Medtronic™ Maverick™

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

9 History of Lumbar TDR SB CHARITÉ™ I II III

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

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

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

13 Design Rationale Footprint Sizes
2 3 4 5

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

15 Design Rationale 2.5mm H Sliding Core Heights H

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

17 David, TJ. Results related to surgeon experience 1989 - 1991
“Lumbar Disc Prosthesis: Five Years Follow-up Study on 147 Patients with 163 SB Charité Prosthesis.” EuroSpine 2003 Results related to surgeon experience 43 patients: 63% excellent/good 57 patients: 82% excellent/good 44 patients: 93% excellent/good Note that outcomes improved over time. By 1997 outcomes were at 93%. This speaks to the need for training. Increasingly superior results correlates with identification of the proper indications, the appropriate patient, the availability of more implant sizes and refinement of the surgical technique and instrumentation. Of additional note is that the U.S. trial was conducted with the during the latter date ranges using the improved instrumentation and refined surgical technique thereby incorporating the learning experience of the European surgeons into the trial.

18 European Experience: Lessons Learned
Sizing Positioning Patient selection 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 Start with plain x-rays, MRI 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

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

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

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

24 Contraindications Scoliosis >11º sagital deformity

25 Contraindications Instability including isthmic spondylolysis
spondylolisthesis 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
Mild Moderate Severe Contraindication: Advanced Facet Disease Severe Spinal Stenosis (canal space < 8mm) Use CT Myelogram to evaluate

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

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

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

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

33 Effectiveness Results (All Randomized)
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). Small P-value indicates high degree of certainty

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

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


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