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