. 2010 May 28;19(8):1262–1280. doi: 10.1007/s00586-010-1445-3

Table 3.

Prospective cohort studies

Study/author	Indication in/exclusion criteria	Demografy/ type of disc for TDR/ Level of intervention	Follow up: duration and outcome
Charité^®
Zeegers et al. [21]	Indication/diagnosis: discopathy (40) post-discectomy discopathies (29) discopathy with possible disc protrusion (6) Exclusion criteria: predominant symptoms or deficits in the legs related to involvement of the nerve roots, spondylolisthesis, spinal stenosis, altered posterior elements, infection, metabolic bone diseases (e.g. osteoporosis, osteomalacia), severe scarring after previous surgery, insufficient motivation of the patient.	N = 50 ♀30 ♂20 mean 43 years (range 24–59 years) Type: Charité III^® Level: 1-level L5/S1 (n = 8), L4/L5 (n = 16), L3/L4 (n = 5) 2-level L4/L5/S1 (n = 12) L3/L4/L5 (n = 5) L5/S1and L3/L4 (n = 1) 3-level L3/L4/L5/S1 (n = 3)	Follow up: 24 months 8–32% lost to follow up Low Back pain (improvement): 65% (30/46) Leg pain (improvement): 64% (27/42) Return to work: 81% (35/43) Narcotic use (decrease): 30% (15/34) Patient Satisfactory (no regret of surgery): 83% (38/46) Overall clinical results (Stauffer Coventry Scale): Good and fair: 70% (32/46), Poor: 30% (14/46) Complication: n = 52 (in 30 patients = 60%) Re-operation: (n = 7) 14%
Regan [22]	Indication/Diagnosis: DDD, sympthomatic Inclusion criteria age between 18–60 years, single level DDD, contained herniated nucleus pulposus, paucity of facet joint degeneration, primary complaint of back pain, failed conservative treatment for at least 6 months, a minimum disc height of 4 mm, scarring/thickening of the annulus fibrosis with osteophytes indicating osteoarthritis. Exclusion criteria: previous thoracic or lumbar fusion, previous surgery on the effected level (except prior discectomy, nondestabilizing laminectomy/otomy without facetectomy, or nucleosis), osteoporosis or metabolic bone disease, radiculair leg pain, lumbar scoliosis, stenosis, segmental instability, spondylosis, spondylolisthesis, spinal neoplasm, active systemic or local infection, facet joint arthrosis, pregnancy, history of chronic steroid use, arachnoiditis, metal allergy, autoimmune disorders, psychosocial disorder, previous retroperitoneal or > 3 intra-abdominal operations	N = 100 ♀46 ♂54 mean 43 years (range 24–59 years) Type: Charité III^® Level: 1-level L5/S1 (n = 68) L4/L5 (n = 32)	Follow up: 6 months (6 weeks, 3, 6 months) 0% lost to follow up Pain (VAS): pre-op: 73.2 (SD14.5), follow up: 39.2 (SD26.4), difference: −34.0 Functional status (ODI): pre-op 53.4% (SD13.4) follow up: 37.6% (SD18.6), difference: −15.8% Complication: n = 9 (10%) Re-operation: n = 7 (7.0%)
Lemaire et al. [20, 23]	Indication/Diagnosis: DDD, sympthomatic Inclusion criteria failed conservative treatment Exclusion criteria: obesity, prior fusion, instability such as spondylolisthesis, deformity, radicular pain symptomology, presence of facet arthrosis	N = 100 ♀59 ♂41 mean 40 years (range 24–51 years) Type: Charité III^® Level: 1-level: (n = 54) 2-level: (n = 45) 3-level: (n = 1) L5/S1 (n = 72) L4/L5 (n = 69) L3/L4 (n = 6)	Follow up: mean 11.3 months (range 10–13.4 years) 7% lost to follow up (n = 107 originally included) Return to work: 91.6% (87/95) Overall clinical results (Stauffer Coventry Scale): Excellent: 62%, Good: 28%, Poor: 10% Complication: n = 16 (16%) Re-operation: n = 5 (5%)
Ross et al. [24]	Indication/Diagnosis: DDD, sympthomatic Inclusion criteria failed conservative treatment, ODI > 30% Exclusion criteria: spondylolisthesis	N = 160 ♀98 ♂62 mean 46 years (range 27–73 years) Type: Charité III^® Level: L5/S1 (n = 114) L4/L5 (n = 92) L3/L4 (n = 20)	Follow up: mean 79 months (range 31–161 months) 23.1% lost to follow up Pain (VAS): pre-op: 63, follow up: 47, difference: −16 Functional status (ODI): pre-op: 51% (26–90) follow up: 37% (0–90) difference: −14% Patient Satisfactory: “much better” 41%, “better” 28%, “same as before” 11%, “worse than before” 20% Complication: n = 53 (33.1%) Re-operation: n = 12 (7.5%) (n = 77/160), *(n = 123/160)
Gioia et al. [25]	Indication/Diagnosis: DDD, sympthomatic Exclusion criteria: disc herniation, spinal canal stenosis, spondylolysis, osteoporosis.	N = 36 ♀23 ♂13 mean 40 years (range 32–49 years) Type: Charité III^® Level: 1-level: (n = 28) 2-level: (n = 7) 3-level: (n = 1) L5/S1 (n = 15) L4/L5 (n = 11) L3/L4 (n = 2)	Follow up: mean 6.9 years (range 5–9 years) lost to follow up not mentioned Pain (VAS): pre-op: 80 (75–83), follow up: 14 (9–19), difference: −66 Functional status (ODI): pre-op: 44% (39.3–48.7), follow up: 9% (5.4–12.2), difference: −35% Patient Satisfactory: “excellent” 72%, “good” 20%, “inadequate” 4%, “poor” 4% Surgery again?: ‘yes’92% (33/36) Complication: n = 11 (30.6%) Re-operation: n = 5 (13.9%)
Warachit [26]	Indication/Diagnosis: DDD, sympthomatic	N = 43 ♀17 ♂26 mean 42 years (range 23–54 years) Type: Charité III^® Level: 1-level: (n = 36) 2-level: (n = 7) L5/S1 (n = 16) L4/L5 (n = 33) L3/L4 (n = 1)	Follow up: 3 years lost to follow up not mentioned Pain (VAS): pre-op: 74, follow up: 13, difference: −61 Functional status (ODI): pre-op: 60.9%, follow up: 9.8% difference: −51.1% Complication: n = 3 (7.0%) Re-operation: n = 1 (2.3%)
Prodisc^®
Bertagnoli et al. [27]	Indication/Diagnosis: Degenerative disc disease (DDD) (n = 67) Failed disc surgery syndrome (n = 35) Transition zone syndrome (TZS) (n = 6) Exclusion criteria: Severe osteoporosis, physiological dysfunction, history of previous infection, severe posterior element pathologies, fracture of the vertebra, tumor.	N = 108 ♀50 ♂58 mean 42 years (range 34–65 years) Type: ProDisc II^® Level: 1-level L5/S1 (n = 61) L5/L6 (n = 3) L4/L5 (n = 31) L3/L4 (n = 7) L2/L3 (n = 3) 2-level L4/L5/S1 (n = 10) L2/L3 and L4/L5 (n = 1) 3-level L3/L4/L5/S1 (n = 2)	Follow up: range 3 months–2 years lost of follow up not mentioned exact, at least 50% lost to follow up at 1 year Return to work: same level 64.8% (n = 35), lower level 31.5% (n = 17), unable 3.7% (n = 2) Resume daily activity: average 2.3 wk (range 1.5–3.2 wk) Overall: excellent 90.8% (n = 98), good 7.4% (n = 8), fair 1.8% (n = 2), poor 0% (n = 0) Complication: n = 1 (1.0%) Re-operations: n = 0
Tropiano et al. [28]	Indication/Diagnosis: DDD, sympthomatic (n = 33) Failed spine surgery (n = 20) Inclusion criteria Failed ≥ 6 months of conservative treatment Exclusion criteria Associated facet degeneration, history of abdominal or retroperitoneal surgery near planned anterior approach, osteoporosis, osteopenia, structural spinal deformities, absence (postoperative) of posterior elements, chronic disease of major organ system, history of local infection, pregnancy	N = 53 ♀35 ♂18 mean 45 years (range 28–68 years) Type: ProDisc II^® Level: 1-level L5/S1 (n = 27), L4/L5 (n = 13), 2-level L4/L5/S1 (n = 9) L3/L4/L5 (n = 2) 3-level L3/L4/L5/S1 (n = 2)	Follow up: mean 1.4 years (range 1–2 years) lost to follow up not mentioned Pain lumbar (VAS): pre-op: 74 (SD 25), follow up: 13 (SD18), difference: −61 Pain radicular (VAS): pre-op: 67 (SD 30), follow up: 19 (SD26), difference: −48 Functional status (ODI): pre-op: 56% (SD 8.2), follow up: 14% (SD 7.4), difference: −42% Return to work: “normal”: 71.7%, “slightly limited”: 28.3%, “impossible”: 13.2% Patient Satisfaction: “entirely satisfied”: 86.8%, “satisfied”: 13.2%, “not satisfied”: 0% Complication: n = 5 (9.4%) Re-operations: n = 3 (5.7%)
Tropiano et al. [29]	Indication/Diagnosis: DDD, symptomatic Inclusion criteria: Single- and multi-level symptomatic DDD confirmed by radiology, severe lumbar pain, failed ≥ 6 months of conservative treatment Exclusion criteria: Facet arthrosis, central or lateral recess stenosis, osteoporosis, sagittal or coronal plane deformity, postoperative absence of posterior elements, sequestrated herniated nucleus pulposis	N = 55 ♀25 ♂30 mean 46 years (range 25–65 years) Type: ProDisc I^® Level: 1-level L5/S1 (n = 10), L4/L5 (n = 17), L4/L5* (n = 6), L3/L4 (n = 2) 2-level L3/L4/L5 (n = 1) L3/L4/L5* (n = 1) L4/L5/S1 (n = 15) 3-level L3/L4/L5/S1 (n = 3) *with concomitant L5–S1 arthrodes	Follow up: mean 104 months (range 84–128 months) 14.1% lost to follow up (n = 64 originally included) Low-back pain (severe or moderate) pre-op: 94.5%, follow-up: 43.6%, difference: −50.9% Lower-limb pain (severe or moderate) pre-op: 85.5%, follow-up: 21.8%, difference: −63.7% Impairment (substantially or limited or impossible) pre-op: 83.6%, follow-up: 20.0%, difference: −63.6% Functional status, Modified Stauffer-Coventry score (scale 0–20) pre-op: 7.0 (SD 3.3), follow up: 16.1 (SD 2.8), difference: ±9.1 Patient Satisfaction: “completely satisfied” 63.6%, “satisfied” 27.3%, “not satisfied” 9.0% Overall: excellent 60%, good 14.5%, poor 25.5% Complications: n = 10 (18.2%) Re-operations: n = 3 (5.5%)
Bertagnoli et al. [30]	Indication/Diagnosis: Single-level DDD, symptomatic Inclusion criteria: Single-level symptomatic DDD at L3–S1 confirmed by radiology, back and/or leg (radicular) pain, failed ≥ 9 months of conservative treatment, age between 18 and 60 years Exclusion criteria: patients with spinal stenosis, osteoporosis, prior fusion surgery, chronic infections, metal allergies, pregnancy, facet arthrosis, inadequate vertebral endplate size, more than one level of spondylosis, neuromuscular disease, Worker’s Compensation, spinal litigation, body mass index greater than 35, and/or any isthmic or degenerative spondylolisthesis greater than Grade 1	N = 104 ♀57 ♂47 median 48 years (range 36–60 years) Type: ProDisc II^® Level: 1-level L5/S1 (n = 80), L4/L5 (n = 17) L3/L4 (n = 7)	Follow up: 24 months (6 weeks, 3, 6, 12, 24 months), 12% lost to follow up (n = 118 originally included) Pain (VAS): pre-op: 75, follow up: 30, difference: −45 Back Pain: No pain: pre-op: 0%, follow up: 32.0%, difference: +32.0% Occasional pain: pre-op: 15.3%, follow up: 59.2%, difference: +43.9% Regular pain: pre-op: 84.6%, follow up: 9.0%, difference: −75.6% Radiculair Pain: No pain: pre-op: 11.9%, follow up: 62.6%, difference: +50.7% Occasional pain: pre-op: 45.5%, follow up: 29.5%, difference: −16.0% Regular pain: pre-op: 42.6%, follow up: 8.8%, difference: −33.8% Functional status (ODI): pre-op: 54% follow up: 29%, difference: −25% Return to work: Full-time: threefold increase, Part-time: fourfold increase, not working: fivefold decrease Patient Satisfactory: “completely satisfied” 58.3%, “satisfied” 38.8%, “unsatisfied” 3.1% Complication: n = 5 (4.2%) Re-operations: n = 1 (1.0%)
Bertagnoli et al. [31]	Indication/Diagnosis: Multi-level DDD, symptomatic Inclusion criteria: Multi-level symptomatic DDD at L1–S1 confirmed by radiology, back and/or leg (radicular) pain, failed ≥ 9 months of conservative treatment, age between 18 and 60 years Exclusion criteria: Patients with spinal stenosis, osteoporosis, prior fusion surgery, chronic infections, metal allergies, pregnancy, facet arthrosis, inadequate vertebral endplate size, more than one level of spondylosis, neuromuscular disease, Worker’s Compensation, spinal litigation, body mass index greater than 35, and/or any isthmic or degenerative spondylolisthesis greater than Grade 1	N = 25 ♀10 ♂15 median 51 years (range 30–60 years) Type: ProDisc II^® Level: 2-level L2/L3 and L4/L5 (n = 1) L3/L4 and L5/S1 (n = 1) L3/L4/L5 (n = 5) L4/L5/S1 (n = 8) 3-level L3/L4/L5/S1 (n = 10)	Follow up: 24 months (6 weeks, 3, 6, 12, 24 months), 13.8% lost to follow up (n = 29 originally included) Pain (VAS): pre-op: 83 (60–100), follow up: 21 (0–60), difference: −62 Back Pain: No pain: pre-op: 0%, follow up: 56%, difference: +56% Episodic pain: pre-op: 8%, follow up: 36%, difference: +28% Regular pain: pre-op: 92%, follow up: 8%, difference: −84% Radiculair Pain: No pain: pre-op: 20%, follow up: 67%, difference: +47% Episodic pain: pre-op: 28%, follow up: 33%, difference: +5% Regular pain: pre-op: 52%, follow up: 0%, difference: −52% Functional status (ODI): pre-op: 65.0% (42–92) follow up: 21.6% (0–48), difference: −43.4% Return to work: Full-time: fivefold increase, Part-time: twofold increase, not working: fourfold decrease Patient Satisfactory: “completely satisfied”: 75%, “satisfied”: 17%, “unsatisfied”: 8% Complication: n = 5 (20%) Re-operations: n = 1 (4.0%)
Chung et al. [32]	Indication/Diagnosis: DDD, symptomatic Inclusion criteria symptomatic DDD at L3–S1 confirmed by radiology, primary complaint of back pain, failed ≥ 6 months of conservative treatment, age between 18 and 60 years, minimum disc height of 4 mm, ODI ≥ 40 Exclusion criteria scoliosis, spondylolysis, spondylolithesis, severe facet degeneration, osteoporosis	N = 36 ♀20 ♂16 mean 43 years (range 25–58 years) Type: ProDisc II^® Level: 1-level: (n = 25) 2-level: (n = 11) L5/S1 (n = 21), L4/L5 (n = 24) L3/L4 (n = 2)	Follow up: 24 months (6 weeks, 12, 24 months), 5.3% lost to follow up (n = 38 originally included) Low back pain (VAS): pre-op: 75, follow up: 30, difference: −45 Leg pain (VAS): pre-op: 47, follow up: 12, difference: −35 Functional status (ODI): pre-op: 69.2%, follow up: 21.0%, difference: −48.2% Clinical success (ODI improvement > 25%): 94.4% (n = 34) Clinical success (ODI improvement > 75%): 44.4% (n = 16) Complication: n = 5 (13.8%) Re-operations: n = 0
Siepe et al. [33, 34], Mayer et al. [36]	Indication/Diagnosis: DDD, symptomatic Inclusion criteria Symptomatic DDD confirmed by radiology, primary complaint of low back pain, failed conservative treatment Exclusion criteria DDD + disc herniation, post-discectomy, DDD + modic changes, central or lateral spinal stenosis, facet joint arthrosis/symptomatic facet joint problems, spondylolysis/spondylolisthesis, spinal instability (iatrogenic/altered posterior elements, e.g., following, laminectomy), major deformity/curvature deviations (e.g., scoliosis), metabolic bone disease (e.g., manifest osteoporosis/osteomalacia), previous operation with severe scarring and radiculopathy, compromised vertebral body (irregular endplate shape), previous/latent infection, metal allergy, spinal tumor, post-traumatic segments	N = 99 ♀60 ♂39 mean 43 years (range 22–66 years) Type: ProDisc II^® Level: 1-level L5/S1 (n = 57), L4/L5 (n = 22), 2-level L4/L5/S1 (n = 20)	Follow up: 12 months (3 m, 6 m, 12 m), 0% lost to follow up (n = 218 included, 99 had reached 12 months FU) pain (VAS): pre-op: 70, follow up: 30, difference: −40 (SD 24) Functional status (ODI): pre-op: 42.0%, follow up: 21.0%, difference: −21.0% (SD 17) Return to work: 66.3% Patient Satisfaction: “completely satisfied” 58.5%, “satisfied” 20.2%, “unsatisfied” 21.3% Complication: n = 17 (17.2%) Re-operations: n = 8 (8.1%)
Ogon et al. [35]	Indication/Diagnosis: degenerative disc disease (DDD) Exclusion criteria spondylarthrosis, spondylolisthesis, spinal stenosis, scoliosis, osteoporosis, infection, tumor	N = 34 ♀26 ♂8 mean 44 years (range 30–60 years) Type: ProDisc ^® Level: 1-level L5/S1 (n = 22), L4/L5 (n = 10), 2-level L4/L5/S1 (n = 2)	Follow up: 12 months (3 m, 12 m), lost to follow up not mentioned pain (VAS): pre-op: 74, follow up: 28, difference: −46 Functional status (ODI): pre-op: 48.0%, follow up: 13.1%, difference: −34.9% Functional status (SF-36) PCSS: pre-op: 31.3, follow up: 44.2, difference: −10.9 MCSS: pre-op: 38.6, follow up: 44.8, difference: −6.2 Patient Satisfaction: “completely satisfied”: 76.5%, “satisfied”: 14.7%, “unsatisfied”: 8.8% Complication: n = 4 (11.8%) Re-operations: n = 1 (2.9%)
Maverick ^®
Huec et al. [37–39]	Indication/Diagnosis: DDD, symptomatic Inclusion criteria: symptomatic DDD confirmed by radiography and MRI, predominant chronic back pain and absence of permanent nerve root compression, failed ≥ 12 months of conservative treatment, ODI > 30%, age between 20 and 60 years irrespective of sex Exclusion criteria: Severe osteoporosis, physiological dysfunction, history of previous infection, severe posterior element pathologies, fracture of the vertebra, tumor.	N = 64 ♀39 ♂25 mean 44 years (range 37–51 years) Intervention: TDR TDR +fusion Type: Maverick^® Level: 1-level: L5/S1 (n = 35), L4/L5 (n = 14), L3/L4 (n = 2) 2-level:L5/S1 TDR + L5/S1 fusion (n = 13)	Follow up: 24 months (1 m, 3 m, 6 m, 12 m, 24 m), 0% lost to follow up Low back pain (VAS): pre-op: 76 (SD17), follow up: 32 (SD18), difference: −44, Leg pain (VAS): pre-op: 39, follow up: 21, difference: −18 Functional status (ODI): pre-op: 43.8% follow up: 23.1%, difference: −20.7% Clinical success (ODI improvement > 25%): 75% Complication: n = 26 (40.6%) Reoperation: n = 0 (0%)
Acroflex ^®
Fraser et al. [40]	Indication/Diagnosis: DDD, sympthomatic Inclusion criteria: 1-level or 2-level symptomatic DDD at L4-S1 confirmed by radiology, back and/or leg (radicular) pain, failed ≥ 6 mo of conservative treatment, age between 30 and 55 years Exclusion criteria: previous lumbar surgery with the exception of discectomy and chemonucleolysis at the target level, steep lumbosacral angle at the target, central or lateral spinal stenosis, spondylolisthesis, systemic disease that would impact the patient’s condition, obesity, alcohol and/or drug abuse, presence of three or more positive Waddell signs, scoliosis, major psychiatric disorder,current involvement in litigation related to the spinal condition or involvement in pursuing legal action related to the spinal condition	N = 28 ♀14 ♂14 mean 41 years (range 30–54 years) Type: Acroflex^® Level: 1-level L5/S1 (n = 19), L4/L5 (n = 5), 2-level:L4/L5/S1 (n = 4)	Follow up: 24 months (6, 12 weeks, 6, 12, 24 months), lost to follow up not mentioned Low back pain (LBOS): pre-op: 17.7, follow up: 33.0, difference: −15.3 Functional status (ODI): pre-op: 49.3% follow up: 34.4%, difference: −14.9% Complication: n = 17 (60.7%) Re-operation: n = 8 (28.6%)

Study/author

Indication
in/exclusion criteria

Demografy/
type of disc for TDR/
Level of intervention

Follow up: duration and outcome

Charité^®

Zeegers et al. [21]

Indication/diagnosis:

discopathy (40)

post-discectomy discopathies (29)

discopathy with possible disc protrusion (6)

Exclusion criteria:

predominant symptoms or deficits in the legs related to involvement of the nerve roots, spondylolisthesis, spinal stenosis, altered posterior elements, infection, metabolic bone diseases (e.g. osteoporosis, osteomalacia), severe scarring after previous surgery, insufficient motivation of the patient.

N = 50 ♀30 ♂20

mean 43 years (range 24–59 years)

Type: Charité III^®

Level:

1-level L5/S1 (n = 8),

L4/L5 (n = 16),

L3/L4 (n = 5)

2-level L4/L5/S1 (n = 12)

L3/L4/L5 (n = 5)

L5/S1and L3/L4 (n = 1)

3-level L3/L4/L5/S1 (n = 3)

Follow up: 24 months

8–32% lost to follow up

Low Back pain (improvement): 65% (30/46)

Leg pain (improvement): 64% (27/42)

Return to work: 81% (35/43)

Narcotic use (decrease): 30% (15/34)

Patient Satisfactory (no regret of surgery): 83% (38/46)

Overall clinical results (Stauffer Coventry Scale): Good and fair: 70% (32/46), Poor: 30% (14/46)

Complication: n = 52 (in 30 patients = 60%)

Re-operation: (n = 7) 14%

Regan [22]

Indication/Diagnosis:

DDD, sympthomatic

Inclusion criteria

age between 18–60 years, single level DDD, contained herniated nucleus pulposus, paucity of facet joint degeneration, primary complaint of back pain, failed conservative treatment for at least 6 months, a minimum disc height of 4 mm, scarring/thickening of the annulus fibrosis with osteophytes indicating osteoarthritis.

Exclusion criteria:

previous thoracic or lumbar fusion, previous surgery on the effected level (except prior discectomy, nondestabilizing laminectomy/otomy without facetectomy, or nucleosis), osteoporosis or metabolic bone disease, radiculair leg pain, lumbar scoliosis, stenosis, segmental instability, spondylosis, spondylolisthesis, spinal neoplasm, active systemic or local infection, facet joint arthrosis, pregnancy, history of chronic steroid use, arachnoiditis, metal allergy, autoimmune disorders, psychosocial disorder, previous retroperitoneal or > 3 intra-abdominal operations

N = 100 ♀46 ♂54

mean 43 years (range 24–59 years)

Type: Charité III^®

Level:

1-level L5/S1 (n = 68)

L4/L5 (n = 32)

Follow up: 6 months (6 weeks, 3, 6 months)

0% lost to follow up

Pain (VAS): pre-op: 73.2 (SD14.5), follow up: 39.2 (SD26.4), difference: −34.0

Functional status (ODI): pre-op 53.4% (SD13.4) follow up: 37.6% (SD18.6), difference: −15.8%

Complication: n = 9 (10%)

Re-operation: n = 7 (7.0%)

Lemaire et al. [20, 23]

Indication/Diagnosis:

DDD, sympthomatic

Inclusion criteria

failed conservative treatment

Exclusion criteria:

obesity, prior fusion, instability such as spondylolisthesis, deformity, radicular pain symptomology, presence of facet arthrosis

N = 100 ♀59 ♂41

mean 40 years (range 24–51 years)

Type: Charité III^®

Level:

1-level: (n = 54)

2-level: (n = 45)

3-level: (n = 1)

L5/S1 (n = 72)

L4/L5 (n = 69)

L3/L4 (n = 6)

Follow up: mean 11.3 months (range 10–13.4 years)

7% lost to follow up (n = 107 originally included)

Return to work: 91.6% (87/95)

Overall clinical results (Stauffer Coventry Scale): Excellent: 62%, Good: 28%, Poor: 10%

Complication: n = 16 (16%)

Re-operation: n = 5 (5%)

Ross et al. [24]

Indication/Diagnosis:

DDD, sympthomatic

Inclusion criteria

failed conservative treatment, ODI > 30%

Exclusion criteria:

spondylolisthesis

N = 160 ♀98 ♂62

mean 46 years (range 27–73 years)

Type: Charité III^®

Level:

L5/S1 (n = 114)

L4/L5 (n = 92)

L3/L4 (n = 20)

Follow up: mean 79 months (range 31–161 months)

23.1% lost to follow up

Pain (VAS): pre-op*: 63, follow up**: 47, difference: −16

Functional status (ODI): pre-op*: 51% (26–90) follow up**: 37% (0–90) difference: −14%

Patient Satisfactory**: “much better” 41%, “better” 28%, “same as before” 11%, “worse than before” 20%

Complication: n = 53 (33.1%)

Re-operation: n = 12 (7.5%)

*(n = 77/160), **(n = 123/160)

Gioia et al. [25]

Indication/Diagnosis:

DDD, sympthomatic

Exclusion criteria:

disc herniation, spinal canal stenosis, spondylolysis, osteoporosis.

N = 36 ♀23 ♂13

mean 40 years (range 32–49 years)

Type: Charité III^®

Level:

1-level: (n = 28)

2-level: (n = 7)

3-level: (n = 1)

L5/S1 (n = 15)

L4/L5 (n = 11)

L3/L4 (n = 2)

Follow up: mean 6.9 years (range 5–9 years)

lost to follow up not mentioned

Pain (VAS): pre-op: 80 (75–83), follow up: 14 (9–19), difference: −66

Functional status (ODI): pre-op: 44% (39.3–48.7), follow up: 9% (5.4–12.2), difference: −35%

Patient Satisfactory: “excellent” 72%, “good” 20%, “inadequate” 4%, “poor” 4%

Surgery again?: ‘yes’92% (33/36)

Complication: n = 11 (30.6%)

Re-operation: n = 5 (13.9%)

Warachit [26]

Indication/Diagnosis:

DDD, sympthomatic

N = 43 ♀17 ♂26

mean 42 years (range 23–54 years)

Type: Charité III^®

Level:

1-level: (n = 36)

2-level: (n = 7)

L5/S1 (n = 16)

L4/L5 (n = 33)

L3/L4 (n = 1)

Follow up: 3 years

lost to follow up not mentioned

Pain (VAS): pre-op: 74, follow up: 13, difference: −61

Functional status (ODI): pre-op: 60.9%, follow up: 9.8% difference: −51.1%

Complication: n = 3 (7.0%)

Re-operation: n = 1 (2.3%)

Prodisc^®

Bertagnoli et al. [27]

Indication/Diagnosis:

Degenerative disc disease (DDD) (n = 67)

Failed disc surgery syndrome (n = 35)

Transition zone syndrome (TZS) (n = 6)

Exclusion criteria:

Severe osteoporosis, physiological dysfunction, history of previous infection, severe posterior element pathologies, fracture of the vertebra, tumor.

N = 108 ♀50 ♂58

mean 42 years (range 34–65 years)

Type: ProDisc II^®

Level:

1-level L5/S1 (n = 61)

L5/L6 (n = 3)

L4/L5 (n = 31)

L3/L4 (n = 7)

L2/L3 (n = 3)

2-level L4/L5/S1 (n = 10)

L2/L3 and L4/L5 (n = 1)

3-level L3/L4/L5/S1 (n = 2)

Follow up: range 3 months–2 years

lost of follow up not mentioned exact, at least 50% lost to follow up at 1 year

Return to work: same level 64.8% (n = 35), lower level 31.5% (n = 17), unable 3.7% (n = 2)

Resume daily activity: average 2.3 wk (range 1.5–3.2 wk)

Overall: excellent 90.8% (n = 98), good 7.4% (n = 8), fair 1.8% (n = 2), poor 0% (n = 0)

Complication: n = 1 (1.0%)

Re-operations: n = 0

Tropiano et al. [28]

Indication/Diagnosis:

DDD, sympthomatic (n = 33)

Failed spine surgery (n = 20)

Inclusion criteria

Failed ≥ 6 months of conservative treatment

Exclusion criteria

Associated facet degeneration, history of abdominal or retroperitoneal surgery near planned anterior approach, osteoporosis, osteopenia, structural spinal deformities, absence (postoperative) of posterior elements, chronic disease of major organ system, history of local infection, pregnancy

N = 53 ♀35 ♂18

mean 45 years (range 28–68 years)

Type: ProDisc II^®

Level:

1-level L5/S1 (n = 27),

L4/L5 (n = 13),

2-level L4/L5/S1 (n = 9)

L3/L4/L5 (n = 2)

3-level L3/L4/L5/S1 (n = 2)

Follow up: mean 1.4 years (range 1–2 years)

lost to follow up not mentioned

Pain lumbar (VAS): pre-op: 74 (SD 25), follow up: 13 (SD18), difference: −61

Pain radicular (VAS): pre-op: 67 (SD 30), follow up: 19 (SD26), difference: −48

Functional status (ODI): pre-op: 56% (SD 8.2), follow up: 14% (SD 7.4), difference: −42%

Return to work: “normal”: 71.7%, “slightly limited”: 28.3%, “impossible”: 13.2%

Patient Satisfaction: “entirely satisfied”: 86.8%, “satisfied”: 13.2%, “not satisfied”: 0%

Complication: n = 5 (9.4%)

Re-operations: n = 3 (5.7%)

Tropiano et al. [29]

Indication/Diagnosis:

DDD, symptomatic

Inclusion criteria:

Single- and multi-level symptomatic DDD confirmed by radiology, severe lumbar pain, failed ≥ 6 months of conservative treatment

Exclusion criteria:

Facet arthrosis, central or lateral recess stenosis, osteoporosis, sagittal or coronal plane deformity, postoperative absence of posterior elements, sequestrated herniated nucleus pulposis

N = 55 ♀25 ♂30

mean 46 years (range 25–65 years)

Type: ProDisc I^®

Level:

1-level L5/S1 (n = 10),

L4/L5 (n = 17),

L4/L5* (n = 6),

L3/L4 (n = 2)

2-level L3/L4/L5 (n = 1)

L3/L4/L5* (n = 1)

L4/L5/S1 (n = 15)

3-level L3/L4/L5/S1 (n = 3)

*with concomitant L5–S1 arthrodes

Follow up: mean 104 months (range 84–128 months)

14.1% lost to follow up (n = 64 originally included)

Low-back pain (severe or moderate) pre-op: 94.5%, follow-up: 43.6%, difference: −50.9%

Lower-limb pain (severe or moderate) pre-op: 85.5%, follow-up: 21.8%, difference: −63.7%

Impairment (substantially or limited or impossible)

pre-op: 83.6%, follow-up: 20.0%, difference: −63.6%

Functional status, Modified Stauffer-Coventry score (scale 0–20)

pre-op: 7.0 (SD 3.3), follow up: 16.1 (SD 2.8), difference: ±9.1

Patient Satisfaction: “completely satisfied” 63.6%, “satisfied” 27.3%, “not satisfied” 9.0%

Overall: excellent 60%, good 14.5%, poor 25.5%

Complications: n = 10 (18.2%)

Re-operations: n = 3 (5.5%)

Bertagnoli et al. [30]

Indication/Diagnosis:

Single-level DDD, symptomatic

Inclusion criteria:

Single-level symptomatic DDD at L3–S1 confirmed by radiology, back and/or leg (radicular) pain, failed ≥ 9 months of conservative treatment, age between 18 and 60 years

Exclusion criteria:

patients with spinal stenosis, osteoporosis, prior fusion surgery, chronic infections, metal allergies, pregnancy, facet arthrosis, inadequate vertebral endplate size, more than one level of spondylosis, neuromuscular disease, Worker’s Compensation, spinal litigation, body mass index greater than 35, and/or any isthmic or degenerative spondylolisthesis greater than Grade 1

N = 104 ♀57 ♂47

median 48 years (range 36–60 years)

Type: ProDisc II^®

Level:

1-level L5/S1 (n = 80),

L4/L5 (n = 17)

L3/L4 (n = 7)

Follow up: 24 months (6 weeks, 3, 6, 12, 24 months),

12% lost to follow up (n = 118 originally included)

Pain (VAS): pre-op: 75, follow up: 30, difference: −45

Back Pain:

No pain: pre-op: 0%, follow up: 32.0%, difference: +32.0%

Occasional pain: pre-op: 15.3%, follow up: 59.2%, difference: +43.9%

Regular pain: pre-op: 84.6%, follow up: 9.0%, difference: −75.6%

Radiculair Pain:

No pain: pre-op: 11.9%, follow up: 62.6%, difference: +50.7%

Occasional pain: pre-op: 45.5%, follow up: 29.5%, difference: −16.0%

Regular pain: pre-op: 42.6%, follow up: 8.8%, difference: −33.8%

Functional status (ODI): pre-op: 54% follow up: 29%, difference: −25%

Return to work: Full-time: threefold increase, Part-time: fourfold increase, not working: fivefold decrease

Patient Satisfactory: “completely satisfied” 58.3%, “satisfied” 38.8%, “unsatisfied” 3.1%

Complication: n = 5 (4.2%)

Re-operations: n = 1 (1.0%)

Bertagnoli et al. [31]

Indication/Diagnosis:

Multi-level DDD, symptomatic

Inclusion criteria:

Multi-level symptomatic DDD at L1–S1 confirmed by radiology, back and/or leg (radicular) pain, failed ≥ 9 months of conservative treatment, age between 18 and 60 years

Exclusion criteria:

Patients with spinal stenosis, osteoporosis, prior fusion surgery, chronic infections, metal allergies, pregnancy, facet arthrosis, inadequate vertebral endplate size, more than one level of spondylosis, neuromuscular disease, Worker’s Compensation, spinal litigation, body mass index greater than 35, and/or any isthmic or degenerative spondylolisthesis greater than Grade 1

N = 25 ♀10 ♂15

median 51 years (range 30–60 years)

Type: ProDisc II^®

Level:

2-level L2/L3 and L4/L5 (n = 1) L3/L4 and L5/S1 (n = 1)

L3/L4/L5 (n = 5)

L4/L5/S1 (n = 8)

3-level L3/L4/L5/S1 (n = 10)

Follow up: 24 months (6 weeks, 3, 6, 12, 24 months),

13.8% lost to follow up (n = 29 originally included)

Pain (VAS): pre-op: 83 (60–100), follow up: 21 (0–60), difference: −62

Back Pain:

No pain: pre-op: 0%, follow up: 56%, difference: +56%

Episodic pain: pre-op: 8%, follow up: 36%, difference: +28%

Regular pain: pre-op: 92%, follow up: 8%, difference: −84%

Radiculair Pain:

No pain: pre-op: 20%, follow up: 67%, difference: +47%

Episodic pain: pre-op: 28%, follow up: 33%, difference: +5%

Regular pain: pre-op: 52%, follow up: 0%, difference: −52%

Functional status (ODI): pre-op: 65.0% (42–92) follow up: 21.6% (0–48), difference: −43.4%

Return to work: Full-time: fivefold increase, Part-time: twofold increase, not working: fourfold decrease

Patient Satisfactory: “completely satisfied”: 75%, “satisfied”: 17%, “unsatisfied”: 8%

Complication: n = 5 (20%)

Re-operations: n = 1 (4.0%)

Chung et al. [32]

Indication/Diagnosis:

DDD, symptomatic

Inclusion criteria

symptomatic DDD at L3–S1 confirmed by radiology, primary complaint of back pain, failed ≥ 6 months of conservative treatment, age between 18 and 60 years, minimum disc height of 4 mm, ODI ≥ 40

Exclusion criteria

scoliosis, spondylolysis, spondylolithesis, severe facet degeneration, osteoporosis

N = 36 ♀20 ♂16

mean 43 years (range 25–58 years)

Type: ProDisc II^®

Level:

1-level: (n = 25)

2-level: (n = 11)

L5/S1 (n = 21),

L4/L5 (n = 24)

L3/L4 (n = 2)

Follow up: 24 months (6 weeks, 12, 24 months),

5.3% lost to follow up (n = 38 originally included)

Low back pain (VAS): pre-op: 75, follow up: 30, difference: −45

Leg pain (VAS): pre-op: 47, follow up: 12, difference: −35

Functional status (ODI): pre-op: 69.2%, follow up: 21.0%, difference: −48.2%

Clinical success (ODI improvement > 25%): 94.4% (n = 34)

Clinical success (ODI improvement > 75%): 44.4% (n = 16)

Complication: n = 5 (13.8%)

Re-operations: n = 0

Siepe et al. [33, 34], Mayer et al. [36]

Indication/Diagnosis:

DDD, symptomatic

Inclusion criteria

Symptomatic DDD confirmed by radiology, primary complaint of low back pain, failed conservative treatment

Exclusion criteria

DDD + disc herniation, post-discectomy, DDD + modic changes, central or lateral spinal stenosis, facet joint arthrosis/symptomatic facet joint problems, spondylolysis/spondylolisthesis, spinal instability (iatrogenic/altered posterior elements, e.g., following, laminectomy), major deformity/curvature deviations (e.g., scoliosis), metabolic bone disease (e.g., manifest osteoporosis/osteomalacia), previous operation with severe scarring and radiculopathy, compromised vertebral body (irregular endplate shape), previous/latent infection, metal allergy, spinal tumor, post-traumatic segments

N = 99 ♀60 ♂39

mean 43 years (range 22–66 years)

Type: ProDisc II^®

Level:

1-level L5/S1 (n = 57),

L4/L5 (n = 22),

2-level L4/L5/S1 (n = 20)

Follow up: 12 months (3 m, 6 m, 12 m),

0% lost to follow up (n = 218 included, 99 had reached 12 months FU)

pain (VAS): pre-op: 70, follow up: 30, difference: −40 (SD 24)

Functional status (ODI): pre-op: 42.0%, follow up: 21.0%, difference: −21.0% (SD 17)

Return to work: 66.3%

Patient Satisfaction: “completely satisfied” 58.5%, “satisfied” 20.2%, “unsatisfied” 21.3%

Complication: n = 17 (17.2%)

Re-operations: n = 8 (8.1%)

Ogon et al. [35]

Indication/Diagnosis:

degenerative disc disease (DDD)

Exclusion criteria

spondylarthrosis, spondylolisthesis, spinal stenosis, scoliosis, osteoporosis, infection, tumor

N = 34 ♀26 ♂8

mean 44 years (range 30–60 years)

Type: ProDisc ^®

Level:

1-level L5/S1 (n = 22),

L4/L5 (n = 10),

2-level L4/L5/S1 (n = 2)

Follow up: 12 months (3 m, 12 m),

lost to follow up not mentioned

pain (VAS): pre-op: 74, follow up: 28, difference: −46

Functional status (ODI): pre-op: 48.0%, follow up: 13.1%, difference: −34.9%

Functional status (SF-36)

PCSS: pre-op: 31.3, follow up: 44.2, difference: −10.9

MCSS: pre-op: 38.6, follow up: 44.8, difference: −6.2

Patient Satisfaction: “completely satisfied”: 76.5%, “satisfied”: 14.7%, “unsatisfied”: 8.8%

Complication: n = 4 (11.8%)

Re-operations: n = 1 (2.9%)

Maverick ^®

Huec et al. [37–39]

Indication/Diagnosis:

DDD, symptomatic

Inclusion criteria:

symptomatic DDD confirmed by radiography and MRI, predominant chronic back pain and absence of permanent nerve root compression, failed ≥ 12 months of conservative treatment, ODI > 30%, age between 20 and 60 years irrespective of sex

Exclusion criteria:

Severe osteoporosis, physiological dysfunction, history of previous infection, severe posterior element pathologies, fracture of the vertebra, tumor.

N = 64 ♀39 ♂25

mean 44 years (range 37–51 years)

Intervention: TDR

TDR +fusion

Type: Maverick^®

Level:

1-level: L5/S1 (n = 35),

L4/L5 (n = 14),

L3/L4 (n = 2)

2-level:L5/S1 TDR +

L5/S1 fusion (n = 13)

Follow up: 24 months (1 m, 3 m, 6 m, 12 m, 24 m),

0% lost to follow up

Low back pain (VAS): pre-op: 76 (SD17), follow up: 32 (SD18), difference: −44,

Leg pain (VAS): pre-op: 39, follow up: 21, difference: −18

Functional status (ODI): pre-op: 43.8% follow up: 23.1%, difference: −20.7%

Clinical success (ODI improvement > 25%): 75%

Complication: n = 26 (40.6%)

Reoperation: n = 0 (0%)

Acroflex ^®

Fraser et al. [40]

Indication/Diagnosis:

DDD, sympthomatic

Inclusion criteria:

1-level or 2-level symptomatic DDD at L4-S1 confirmed by radiology, back and/or leg (radicular) pain, failed ≥ 6 mo of conservative treatment, age between 30 and 55 years

Exclusion criteria:

previous lumbar surgery with the exception of discectomy and chemonucleolysis at the target level, steep lumbosacral angle at the target, central or lateral spinal stenosis, spondylolisthesis, systemic disease that would impact the patient’s condition, obesity, alcohol and/or drug abuse, presence of three or more positive Waddell signs, scoliosis, major psychiatric disorder,current involvement in litigation related to the spinal condition or involvement in pursuing legal action related to the spinal condition

N = 28 ♀14 ♂14

mean 41 years (range 30–54 years)

Type: Acroflex^®

Level:

1-level L5/S1 (n = 19),

L4/L5 (n = 5),

2-level:L4/L5/S1 (n = 4)

Follow up: 24 months (6, 12 weeks, 6, 12, 24 months),

lost to follow up not mentioned

Low back pain (LBOS): pre-op: 17.7, follow up: 33.0, difference: −15.3

Functional status (ODI): pre-op: 49.3% follow up: 34.4%, difference: −14.9%

Complication: n = 17 (60.7%)

Re-operation: n = 8 (28.6%)

VAS (scale 0–100), ODI (scale 0–100)

All ODI scores and VAS scores were converted into 0–100 scale