introduction to spine arthroplasty ira fedder, md scoliosis and spine center towson, md depuy spine...
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Introduction to Spine Introduction to Spine Arthroplasty Arthroplasty
Ira Fedder, MDIra Fedder, MDScoliosis and Spine Center Scoliosis and Spine Center Towson, MDTowson, MD
DePuy Spine confidential information. Do not duplicate. Do not distribute.
Spine Surgery at the Spine Surgery at the MillenniumMillennium
Posterolateral +/- Posterolateral +/- InstrumentationInstrumentation
Circumferential (“360°”)Circumferential (“360°”) PLIF PLIF (Posterior Lumbar Interbody (Posterior Lumbar Interbody
Fusion)Fusion) ALIFALIF (Anterior Lumbar Interbody (Anterior Lumbar Interbody
Fusion)Fusion) TLIFTLIF (Transforaminal Lumbar (Transforaminal Lumbar
Interbody Fusion)Interbody Fusion)
ParadoxParadox
Can the same problem Can the same problem (discogenic pain) be treated (discogenic pain) be treated
effectively using interventions effectively using interventions with the exact opposite with the exact opposite
technical goals?technical goals?
80%80% AnterioAnterio
rr
20%20%PosterioPosterio
rr
BiomechanicsBiomechanics
The 80-20 rule of Spine loading
History of Lumbar TDRHistory of Lumbar TDR
Fernström – 1960’s
History of Lumbar TDRHistory of Lumbar TDR
Synthes™
PRODISC®
I - 1987 PRODISC® II - 1999
History of Lumbar TDRHistory of Lumbar TDR
Medtronic™
Maverick™ - 2001
Karin BKarin Büüttner-Janzttner-JanzINVENTORINVENTOR
HistoryHistory
DePuy Spine confidential information. Do not duplicate. Do not distribute.
History of Lumbar TDRHistory of Lumbar TDR
I - 1984 II - 1985 III - 1987
SB CHARITÉ™
HistoryHistoryDesign IterationsDesign Iterations
Inventors Drs. Schellnack and Inventors Drs. Schellnack and Büttner-JanzBüttner-Janz
SB CharitéSB Charité™™ I I 19841984 13 patients, 14 Implants13 patients, 14 Implants
SB Charité SB Charité ™™ II II 19851985 36 patients, 44 Implants36 patients, 44 Implants
Non-forged stainless steelNon-forged stainless steel No special instrumentationNo special instrumentation
Data from Data from The Artificial DiscThe Artificial Disc, Buttner-Janz, , Buttner-Janz, 20032003
Experimental Experimental PrototypesPrototypes
Never Commercially Never Commercially AvailableAvailable
History - Current Design History - Current Design CHARITÉ Artificial DiscCHARITÉ Artificial Disc
Refined design by Waldemar Refined design by Waldemar LinkLink Cast Cobalt Chrome EndplatesCast Cobalt Chrome Endplates Ultra High Molecular Weight Ultra High Molecular Weight
Polyethylene (UHMWPE) Sliding Polyethylene (UHMWPE) Sliding CoreCore
Design unchanged since 1987Design unchanged since 1987 First released 1987First released 1987
Thousands of implantations Thousands of implantations worldwideworldwide
Same design used in U.S. IDE Same design used in U.S. IDE clinical studyclinical study
17-year track record17-year track record
Importance of SizingImportance of Sizing
Proper Endplate SizeProper Endplate Size Bone DensityBone Density
Dr. Wolfgang Raushning - Uppsala University, Sweden 2000Dr. Wolfgang Raushning - Uppsala University, Sweden 2000
David, TJ.David, TJ.
Results related to surgeon experienceResults related to surgeon experience 1989 - 1991 1989 - 1991
43 patients: 63% excellent/good43 patients: 63% excellent/good 1992 - 19941992 - 1994
57 patients: 82% excellent/good57 patients: 82% excellent/good 1995 - 19971995 - 1997
44 patients: 93% excellent/good44 patients: 93% excellent/good
“Lumbar Disc Prosthesis: Five Years Follow-up Study on 147 Patients with 163 SB Charité Prosthesis.” EuroSpine 2003
European Experience:European Experience: Lessons Learned Lessons Learned
SizingSizing PositioningPositioning Patient selectionPatient selection Controlled distractionControlled distraction
Learning ObjectivesLearning Objectives
Patient SelectionPatient SelectionPatient SelectionPatient SelectionPatient SelectionPatient Selection
Radiographic EvaluationRadiographic Evaluation
We We AREARE treating discogenic pain with treating discogenic pain with TDRTDR
Biggest challenge is to identify the pain generatorBiggest challenge is to identify the pain generator
Start with plain x-rays, MRIStart with plain x-rays, MRI
Studies have shown high false positive rate of Studies have shown high false positive rate of MRIsMRIs
Discography can help distinguish between Discography can help distinguish between asymptomatic “dark discs” on MRI and those that asymptomatic “dark discs” on MRI and those that are pain generatorsare pain generators
DiscographyDiscography
Clinical pain provocation testClinical pain provocation test Radiographic imagesRadiographic images Test is positive only if:Test is positive only if:
The disc is abnormal in The disc is abnormal in appearance appearance
ANDAND Patient’s clinical pain is Patient’s clinical pain is
provoked during injectionprovoked during injection
Clinical IndicationsClinical Indications
Chronic low back pain +/- leg painChronic low back pain +/- leg pain Persisting > 6 monthsPersisting > 6 months Associated with degenerative disc changesAssociated with degenerative disc changes
Leg painLeg pain RadicularRadicular PseudoradicularPseudoradicular
Foraminal stenosisForaminal stenosis Secondary to disc space height lossSecondary to disc space height loss
may be relieved indirectly by disc height may be relieved indirectly by disc height restorationrestoration
ContraindicationsContraindications
Dexa-scan Dexa-scan patients > age 50 patients > age 50 or with more than or with more than 1 risk factor1 risk factor
T< -1.0 is T< -1.0 is contraindicatedcontraindicated
Osteoporosis or Osteoporosis or OsteopeniaOsteopenia
ContraindicationsContraindications
Scoliosis >11º sagital deformityScoliosis >11º sagital deformity
ContraindicationsContraindications
InstabilityInstability including including isthmic spondylolysisisthmic spondylolysis spondylolisthesisspondylolisthesis retro or anteriolisthesis retro or anteriolisthesis
> 3mm> 3mm
ContraindicationsContraindicationsPoor psychometric Poor psychometric
evaluationevaluation
Abnormal pain discogramAbnormal pain discogram
Hz of SchizophreniaHz of Schizophrenia
Bi-polar conditionBi-polar condition
Severe depressionSevere depression
Inability to comprehend Inability to comprehend procedure and risksprocedure and risks
Facet DiseaseFacet Disease
Contraindication:Contraindication:
Advanced Facet DiseaseAdvanced Facet Disease
Severe Spinal Stenosis (canal space < Severe Spinal Stenosis (canal space < 8mm)8mm)
Use CT Myelogram to evaluateUse CT Myelogram to evaluate
ModerateMild
Severe
ContraindicationsContraindications
Central StenosisCentral Stenosis TumorTumor ArachnoiditisArachnoiditis History of chronic History of chronic
steroid usesteroid use Advanced facet Advanced facet
diseasedisease Facet joint ankylosis Facet joint ankylosis Metal allergiesMetal allergies
PregnancyPregnancy Single or bilateral leg Single or bilateral leg
pain (due to nerve pain (due to nerve compression)compression)
Non-contained Non-contained herniated nucleus herniated nucleus pulposuspulposus
Infection/neoplasmInfection/neoplasm Autoimmune Autoimmune
disordersdisorders
Approach Related Approach Related ContraindicationsContraindications
Anterior Vascular Anterior Vascular Calcification Calcification
Previous major vessel Previous major vessel surgerysurgery
Obesity: BMI > 40 or 100lbs Obesity: BMI > 40 or 100lbs over ideal body weightover ideal body weight
Previous retroperitoneal Previous retroperitoneal proceduresprocedures
Effectiveness Results Effectiveness Results (All Randomized)(All Randomized)
Small P-value indicates high degree of Small P-value indicates high degree of certaintycertainty
Primary Hypothesis: Overall Success Primary Hypothesis: Overall Success RateRateConclusionConclusion: The CHARITÉ Artificial Disc is at : The CHARITÉ Artificial Disc is at least equivalent in overall success to the BAK least equivalent in overall success to the BAK cage in treatment of DDD at one level (L4-S1).cage in treatment of DDD at one level (L4-S1).
Overall Success CHARITÉ BAK Cage Blackwelder’s Test P-Value*
N (completers) 184 81 Yes 107 (58%) 44 (54%) <.0173 No 77 (42%) 37 (46%) *Blackwelder’s test: delta=.10 Ho:Pbak = PBsb + delta, Ha:PBAK <= Psb + delta
Effectiveness Results Effectiveness Results (All Randomized)(All Randomized)
Characteristic CHARITÉ BAK Cage N (completers) 184 81
15pt improvement in Oswestry Yes 117 (64%) 47 (58%) No 67 (36%) 34 (42%)
Device failures* Success 175 (95%) 74 (91%) Failure 9 (5%) 7 (9%)
Major complications** Success 182 (99%) 80 (99%) Failure 2 (1%) 1 (1%)
Neurological deterioration Success 167 (91%) 77 (95%) Failure 17 (9%) 4 (5%) Overall Success Rate 107 (58%) 44 (54%)
Characteristic CHARITÉ BAK Cage N (completers) 184 81
15pt improvement in Oswestry Yes 117 (64%) 47 (58%) No 67 (36%) 34 (42%)
Device failures* Success 175 (95%) 74 (91%) Failure 9 (5%) 7 (9%)
Major complications** Success 182 (99%) 80 (99%) Failure 2 (1%) 1 (1%)
Neurological deterioration Success 167 (91%) 77 (95%) Failure 17 (9%) 4 (5%) Overall Success Rate 107 (58%) 44 (54%)
* re-operation, revision, removal or additional fixation* re-operation, revision, removal or additional fixation
** major vessel injury, neurological damage or nerve root ** major vessel injury, neurological damage or nerve root injuryinjury
Primary Effectiveness EndpointsPrimary Effectiveness Endpoints
Implant Lateral X-Ray FinalImplant Lateral X-Ray Final
Center of rotation 2mm dorsal sagital midlineCenter of rotation 2mm dorsal sagital midlinemaximum footprint coverage – proper lordotic anglesmaximum footprint coverage – proper lordotic angles
Implant A/P X-Ray FinalImplant A/P X-Ray Final
Center spike positioned on A/P midlineCenter spike positioned on A/P midline
Final PositionFinal Position
Final AP & Lateral PositionFinal AP & Lateral Position