Article Figures & Data
Tables
Anatomical / inherent / degenerative / mechanical Subsidence / dislocation risk Pars defects37 Osteoporosis7, 9, 19, 21, 25, 26, 33, 34, 36, 43, 8, 29, 30, 37, 38, 44, 49, 65, 79, 80 Fracture at L4, L5 or S19 or compromised vertebral body7, 16, 24, 29, 35, 38, 79, 81 Endocrine or metabolic disorder known to affect osteogenesis36 Disc height < 3mm10, <4mm7 Metabolic bone disease7, 9, 19, 21, 24, 29, 37, 43, 49, 81 End stage disc resorption and collapse19 Osteopenia7, 9, 12, 16, 19, 21, 26, 31, 37, 49, 82 Facet ankylosis7 Osteopathy7 Facet joint arthrosis/degeneration7–12, 14–17, 19, 21, 24–26, 29–31, 33–35, 37, 38, 41, 44, 49, 65, 78–83 Paget disease7, 21 Retrolisthesis7 Chronic steroid use9, 19, 21, 29, 37, 49, 83 Posterior element insufficiency7, 21, 24, 26, 36, 43, 65 Postsurgical deficiency of posterior elements 25, 31 or prior posterior lumbar surgery with significant morbidity36 Pathology not, or possibly not, treatable by TDR Scoliosis 7, 9, 12, 13, 16, 21, 24, 31, 33–37, 40, 49, 65, 81, 84 or major deformity15, 19, 25, 26, 29, 37, 38, 41, 44, 82 Nerve root compression7, 16, 35 Irregular vertebral body endplate shape7, 24, 29, 81 Positive straight leg raise9 Spondylosis7, 9, 16, 21, 24, 30, 31, 35, 37, 43, 49, 65, 81, 82 Radicular pain symptomology7, 15, 19, 29, 37, 43, 81, 82 Spondylolisthesis7, 9, 11, 13, 15, 16, 19, 24, 29–31, 33–38, 41, 43, 44, 49, 65, 78, 80–83 Straight leg raise producing pain below knee16, 35, 37 Isthmic spondylolysis / olisthesis19, 21, 38 Noncontained herniated nucleus pulposus7, 9, 12, 16, 19, 25, 31, 33, 34, 49, 65, 82 Lumbosacral joint anomalies81 Scarring from previous surgery43 Instability14, 21, 24, 37, 40, 81 Arachnoiditis7, 9, 12, 19, 49 Prior decompressive laminectomy12 Stenosis7, 9, 12, 13, 19, 21, 24, 25, 29–31, 33, 34, 36–38, 41, 43, 44, 49, 65, 78, 81, 82 Previous fusion7, 9, 11, 15, 16, 19, 21, 29, 30, 33, 34, 36–38, 44, 49, 79 Multilevel degeneration beyond 1 or 2 levels specified for TDR9, 19, 29, 33, 34, 36–38, 49 Pseudoarthrosis7, 12, 31, 65 Previous spinal surgery at affected level – except for discectomy, laminotomy/ectomy, without accompanying facetotomy, or intradiscal procedures at the level to be treated9, 13, 24, 36, 49, 81 Fibromyalgia7 Possibly reaction on implant material Cervical myelopathy21 History of hypersensitivity to protein pharmaceuticals or collagen36 History of implant rejection19 General Metal allergy7, 9, 19, 24, 29, 30, 34, 36, 37, 44, 49, 79, 81 Infection7–9, 19, 24, 26, 29, 30, 34, 36–38, 41, 43, 44, 49, 81 History of anaphylaxis36 Active hepatitis21 Active malignancy19, 21, 29, 34, 36, 37 Anterior approach related 3 or more Waddell signs13 Obesity – definition varied with study7-913, 15, 16, 19, 21, 29, 30, 34, 35, 37, 44, 49 Autoimmune disorder7, 9, 19, 21, 29, 34, 36, 37, 49, 83 Vascular anatomy that is aberrant7 Pregnancy7, 19, 9, 26, 29, 30, 34, 38, 41, 44, 49, 79 Vascular calcification7 Psychosocial disorder7, 36, 8, 9, 12, 13, 19, 37, 38, 49, 80 Previous abdominal surgery7, 26, 37 Osteomyelitis7 Abdominal wall hernia12 Spondylodiscitis7 Previous iliofemoral phlebitis12 Chronic disease of a major organ – cardiac failure, hepatitis, diabetes7, 26 Abdominal pain profile19 Neuromuscular disease30, 44 Previous vascular surgery7 Ankylosing spondylitis7 Prior retroperitoneal radiation7, 12, 19 Spinal tumor7, 9, 16, 19, 24, 35, 37, 38, 41, 49, 81 Prior surgery at the involved level7, 19, 36, 37, 41, 81 Other Previous exposure to any or all bone morphogenetic proteins (human or animal)36 Name of TDR Design Material Functional three-component Charité Artificial Disc (DePuy Spine) A 3 component ball and socket, 2 equal articulating surfaces CoCr – UHMWPE – CoCr InMotion (DePuySpine) A 3 component ball and socket, 2 equal articulating surfaces (furtherdevelopment of Charité Artificial Disc) CoCr – UHMWPE – CoCr Kineflex-L (SpinalMotion, Inc.) I 3 component ball and socket, 2 equal articulating surfaces CoCr – CoCr – CrCo Activ L (Aesculap /BBraun) I 3 component ball and socket, 2 equal articulating surfaces CoCr – UHMWPE - CoCr Dynardi (Zimmer) NA 3 component ball and socket, 2 equal articulating surfaces CoCr – Sulene PE - CoCr Mobidisc (LDRSpine)I 3 component with 2 articulating surfaces: 1 ball and socket superior surfaceand 1 flat inferior surface CoCr – UHMWPE – CoCr Orbit (GlobusMedical)NA 3 component with 2 articulating surfaces: 1 ball and socket superior surfaceand 1 cylindrical inferior surface (for extension/flexion) PEEK – PEEK - PEEK Functional two-component ProDisc-L (DePuySynthes) A 3 component ball and socket, 1 articulating surface, core affixed to caudalplate CoCr – UHMWPE-CoCr Maverick (Medtronic)I 2 component ball and socket, 1 articulating surface CoCr – CoCr Flexicore (Stryker) I 2 component ball and socket, 1 articulating surface, internal stiff stop ofaxial rotation CoCr – CoCr XL TDR (NuVasive)I 2 component ball and socket, 1 articulating surface CoCr - CoCr Functional one-component Freedom (AxioMed) I 1-piece bonded viscoelastic, no articulating surface Ti – SPCU - Ti M6-L (SpinalKinetics, Inc.)NA 1-piece viscoelastic, with movable core - not bonded to plates Ti - PCU core - Ti, UHMWPE fiber annulus, PCU sheath Cadisc-L (Ranier)NA 1-piece bonded viscoelastic, no articulating surface PCU with graduated modulus LP-ESP (FHOrthopedics) NA 1-piece viscoelastic, no articulating surface Ti plates, silicone core filled withmicrovoids, surrounded by PCU Physio-L (K2M) NA 1-piece viscoelastic, no articulating surface Ti – PCU – Ti multidurometer core CoCr = cobalt chrome; PCU = polycarbonate urethane; SPCU = silicone polycarbonate urethane; Ti = titanium alloy; UHMWPE = ultra high molecular weight polyethylene
FDA status: A Approved; I Investigational; NA Not approved, not involved in IDE trial at this time
Characteristic Compared to Natural Disc Metal-on-Metal Metal-on-Poly Viscoelastic one-Piece 1. Restoration of normal/adjacent Disc Height (+) (+) (+) 2. Restoration of Disc Angle (+) (+) (+) 3. Mimics Quantity of Motion (ROM) - - (-) 4. Mimics Quality of Motion (stiffness, COR, NZ) - - (-) 5. Stability (Passive Restraint) - - (+) 6. Shock Damping - (-) + 1. & 2. Restoration of normal disc height and disc angle depends on the assortment of available implants in relation to patient's disc height and disc angle variations. The disc height is most stable in the long run in metal-on-metal discs, followed by metal-on-poly implants. Most viscoelastic one-piece discs can better sustain the disc angle than functional 2- or 3-component discs.
3. No disc has physiological ROM to the different directions (sagittal, frontal, transversal plane). Spherical ball and socket discs imply always hypermobility.
4. There is no disc with complete qualitative physiological features.
5. Stability is not to separate from quantity and quality of motion. The intervertebral motion has much more resistance in viscoelastic discs.
6. Damping function is the pre-condition for any motion in viscoelastic one-piece discs. Material Poly has a low degree of elasticity.
- Table 4
Proposed overview how to determine types of TDR in relation to patient selection criteria.
Preoperative factor Functional three component spherical ball and socket disc Functional two component spherical ball and socket disc One-piece viscoelastic disc with movable core Compact (stiff) one-piece viscoelastic disc Patient Selection Criteria Patient data and medical history Age 20-40 20-40 30-50 40- >60 (precondition >50 y: sclerosis of endplates) Back pain yes yes yes yes Leg pain yes yes yes yes, no > 50 y Duration of non-surgical treatment 20-30 y: 9 months 30-40 y: 6 months 20-30 y: 9 months 30-40 y: 6 months 30-40 y: 6 months 40-50 y: 5 months 40-50 yrs: 5 months 50-60 yrs: 4 months >60: 3 months Prior surgery no (besides nucleotomy/discectomy without destabilizing bone resection) no (besides nucleotomy/discecomy without destabilizing bone resection) no (besides nucleotomy/discectomy without destabilizing bone resection) yes (without facet-resection or laminectomy) Pain and disability VAS > 50/100 > 50/100 > 40/100 > 40/100 ODI >macr; 40/100 >macr; 40/100 >macr; 40/100 >macr; 40/100 Clinical findings No severe nerve stretching findings no severe nerve stretching findings no severe nerve stretching findings no severe nerve stretching findings No severe nerve stretching findings Radiographic findings Maximal reduced disc height compared to upper healthy disc 1/2 1/2 1/2 2/3 Osteochondrosis yes yes yes yes Degenerative spondylolisthesis no no no Yes< 3mm Isthmic spondylolisthesis no no no no Degenerative scoliosis no no minimal yes Bony stenosis of spinal canal no no no no Facet arthritis grades85 up to grade II up to grade II up to grade II up to grade III Facetectomy no no no no MRI Nucleus pulposus prolapse at disc level with nerve root irritation (= anterior discectomy possible) yes yes yes yes Modic changes yes yes yes yes Invasive diagnostic procedures Facet joint injection no reduced pain no reduced pain no reduced pain < 50% reduced pain Specific pain at discography yes yes yes yes Reduced leg pain at periradicular injection +/- +/- +/- +/- Bone quality DEXA T > -1.0 T > -1.0 T > -1.0 T > -1.0 Psychosocial / psychological factors Result of test(s) negative negative negative negative Surgical experience Possible number of levels 1 1-2 1-2 > 2
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