Document

Report
Introduction to Spine
Arthroplasty
Ira Fedder, MD
Scoliosis and Spine Center
Towson, MD
DePuy Spine confidential information. Do not duplicate. Do not distribute.
Spine Surgery at the
Millennium
Posterolateral +/- Instrumentation
 Circumferential (“360°”)




PLIF (Posterior Lumbar Interbody
Fusion)
ALIF (Anterior Lumbar Interbody
Fusion)
TLIF (Transforaminal Lumbar Interbody
Fusion)
Paradox
Can the same problem (discogenic
pain) be treated effectively using
interventions with the exact opposite
technical goals?
Biomechanics
80%
Anterior
20%
Posterior
The 80-20 rule of Spine loading
History of Lumbar TDR
Fernström – 1960’s
History of Lumbar TDR
Synthes™
PRODISC® I - 1987
PRODISC® II - 1999
History of Lumbar TDR
Medtronic™
Maverick™ - 2001
History
Karin Büttner-Janz
INVENTOR
DePuy Spine confidential information. Do not duplicate. Do not distribute.
History of Lumbar TDR
SB CHARITÉ™
I - 1984
II - 1985
III - 1987
History
Design Iterations


Inventors Drs. Schellnack and
Büttner-Janz
SB Charité I
™



1984
13 patients, 14 Implants
SB Charité II
™




Experimental Prototypes
Never Commercially
Available
1985
36 patients, 44 Implants
Non-forged stainless steel
No special instrumentation
Data from The Artificial Disc, Buttner-Janz, 2003
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
Importance of Sizing
Proper Endplate Size
Bone Density
Dr. Wolfgang Raushning - Uppsala University, Sweden 2000
David, TJ.
“Lumbar Disc Prosthesis: Five Years Follow-up Study on 147
Patients with 163 SB Charité Prosthesis.” EuroSpine 2003
Results related to surgeon experience
 1989 - 1991


1992 - 1994


43 patients: 63% excellent/good
57 patients: 82% excellent/good
1995 - 1997

44 patients: 93% excellent/good
European Experience:
Lessons Learned
Sizing
 Positioning
 Patient selection
 Controlled distraction

Learning Objectives
 Patient Selection
 Patient Selection
 Patient Selection
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
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
Clinical Indications

Chronic low back pain +/- leg pain



Leg pain



Persisting > 6 months
Associated with degenerative disc changes
Radicular
Pseudoradicular
Foraminal stenosis

Secondary to disc space height loss

may be relieved indirectly by disc height restoration
Contraindications
Osteoporosis or Osteopenia


Dexa-scan patients
> age 50 or with
more than 1 risk
factor
T< -1.0 is
contraindicated
Contraindications
Scoliosis >11º sagital deformity
Contraindications
Instability including
 isthmic
spondylolysis
 spondylolisthesis
 retro or anteriolisthesis >
3mm
Contraindications
Poor psychometric evaluation
 Abnormal pain discogram
 Hz of Schizophrenia
 Bi-polar condition
 Severe depression
 Inability to comprehend
procedure and risks
Facet Disease
Mild
Moderate
Severe
Contraindication:
 Advanced Facet Disease
 Severe Spinal Stenosis (canal space < 8mm)
 Use CT Myelogram to evaluate
Contraindications
Central Stenosis
 Tumor
 Arachnoiditis
 History of chronic steroid
use
 Advanced facet disease
 Facet joint ankylosis
 Metal allergies






Pregnancy
Single or bilateral leg
pain (due to nerve
compression)
Non-contained herniated
nucleus pulposus
Infection/neoplasm
Autoimmune disorders
Approach Related
Contraindications
Anterior Vascular Calcification
 Previous major vessel surgery
 Obesity: BMI > 40 or 100lbs
over ideal body weight
 Previous retroperitoneal
procedures

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).
Overall Success
CHARITÉ
BAK Cage
Blackwelder’s Test
P-Value*
N (completers)
184
81
<.0173
Yes
107 (58%)
44 (54%)
No
77 (42%)
37 (46%)
*Blackwelder’s test: delta=.10 Ho:Pbak = PBsb + delta, Ha:PBAK <= Psb + delta

Small P-value indicates high degree of certainty
Effectiveness Results
(All Randomized)
Primary Effectiveness Endpoints
Characteristic
N (completers)
15pt improvement in Oswestry
Yes
No
Device failures*
Success
Failure
Major complications**
Success
Failure
Neurological deterioration
Success
Failure
Overall Success Rate
CHARITÉ
BAK Cage
184
81
117 (64%)
67 (36%)
47 (58%)
34 (42%)
175 (95%)
9 (5%)
74 (91%)
7 (9%)
182 (99%)
2 (1%)
80 (99%)
1 (1%)
167 (91%)
17 (9%)
107 (58%)
77 (95%)
4 (5%)
44 (54%)
* re-operation, revision, removal or additional fixation
** major vessel injury, neurological damage or nerve root injury
Implant Lateral X-Ray Final
Center of rotation 2mm dorsal sagital midline
maximum footprint coverage – proper lordotic angles
Implant A/P X-Ray Final
Center spike positioned on A/P midline
Final Position
Final AP & Lateral Position

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