From: Proposal for a classification system of radiographic bone changes after cervical disc replacement
Device SSED | IDE # of patients | Follow-up | Heterotopic ossification classification type | Radiolucencies | Disc height measurement | Migration/subsidence/loosening | Radiographic success |
---|---|---|---|---|---|---|---|
Prestige (one-level) July 2007 | 276 | 6 weeks, 3-, 6-, 12-, 24-months and annually thereafter | NR | NR | Assessment criteria: maintenance of height (height change ≤ 2 mm from 6-week post-op height) Success at 24 mos: 90/92 (97.8%) | Assessment criteria: NR Displacement/Loosening (reported as AE): 2/276 patients (0.7%), 2 events Subsidence (reported as AE): 1/276 patients (0.4%), 1 event | Assessment criteria: (I) the existence of flexion/extension angular motion in a range of > 4° to ≤ 20° and 2) no evidence of bridging trabecular bone forming a continuous connection between vertebral bodies Success at 24 mos: 85/117 (72.6%) |
Prodisc (one-level) December 2007 | 103 | 6 weeks, 3-, 6-, 12-, 18-, and 24-months | Assessment criteria: reported as “bridging bone” Result at 24 mos: 3/98 (3.0%) | Assessment criteria: radiolucencies > 25% around implant Result at 24 mos: 0/98 (0.0%) | Assessment criteria: height decrease > 3 mm (baseline unclear) Result at 24 mos: 0/98 (0.0%) | Assessment criteria: device motion > 3 mm Migration at 24 mos: 0/98 (0.0%) Subsidence at 24 mos: 0/98 (0.0%) | NR |
Bryan (one-level) May 2009 | 242 | 6 weeks, 3-, 6-, 12-, 24-months and biennially thereafter | Assessment criteria: reported as “bridging bone” Result at 24 mos: 0/154 (0.0%) | Assessment criteria: NR Result at 24 mos: 0/154 (0.0%) | Assessment criteria: maintenance of height (height change ≤ 2 mm from 3-month post-op height) Reported as part of radiographic success | Assessment criteria: Subsidence success defined as ≤ 2 mm decrease from the 3-month measurement Reported as part of Radiographic Success | Assessment criteria: FSU height/subsidence success based on a patient not having a surgical intervention related to a failure finding for either FSU or subsidence Success at 24 mos: 79.6% |
Secure-C (one-level) September 2012 | 236 (148 randomized, 88 training) | 6 weeks, 3-, 6-, 12-, 24-months and annually thereafter | Assessment criteria: Graded 0–IV per Mehren classification Result at 24 mos: Grade 0: 51/198 (25.8%) Grade I: 40/198 (20.2%) Grade II: 69/198 (34.8%) Grade III: 25/198 (12.6%) Grade IV: 13/198 (6.6%) | Assessment criteria: Radiolucencies > 25% around implant Result at 24 months: 0 (0.0%) | Assessment criteria: height change > 2 mm from pre-op baseline Result at 24 mos: 89/189 (47.1%) | Assessment criteria: device motion > 3 mm Migration/displacement/subsidence at 24 mos: 0 (0.0%) | NR |
PCM (one-level) October 2012 | 289 (214 randomized, 75 training) | 6 weeks, 3-, 6-, 12-, 24-months and annually thereafter | Assessment criteria: Graded 0–IV per Mehren classification Result at 24 mos: Grade 0: 141/233 (60.5%) Grade I: 34/233 (14.6%) Grade II: 48/233 (20.6%) Grade III: 7/233 (3.0%) Grade IV: 3/233 (1.3%) | Assessment criteria: Radiolucencies > 50% length of prosthesis Result at 24 mos: 14/182 (7.7%; all superior) AE reports Occurance at 24 mos: 3/214 patients (1.4%) | Assessment criteria: maintenance of height (≥ 80% of post-op baseline) Result at 24 mos: 160/177 (90.4%) | Assessment criteria: NR AE reports Subsidence at 24 mos: 1/214 patients (0.5%) Displacement/Loosening at 24 + mos: 10/214 patients (4.7%) | Assessment criteria: lack of evidence of continuous bridging bone between the adjacent endplates of the involved motion segment or > 2° of segmental movement on lateral flexion/extension radiographs Success at 24 mos: 178/180 (98.9%) |
Mobi-C (one-level) August 2013 | 179 (164 randomized, 15 training) | 6 weeks, 3-, 6-, 12-, 18-, 24-months and annually thereafter | Assessment criteria: Graded 0–IV per Mehren classification Result at 24 mos: Grade 0: 14/164 (8.5%) Grade I: 13/164 (7.9%) Grade II: 109/164 (66.5%) Grade III: 16/164 (9.8%) Grade IV: 10/164 (6.1%) AE reports Occurance at 24 mos: 9/179 patients (5.0%), 10 events Occurance at 60 mos: 13/179 patients (7.3%), 16 events | Assessment criteria: categorized as none, mild (< 25%), moderate (25–50%), or severe (> 50%) Result 24 mos: mild radiolucency in 2 (1.3%) | Assessment criteria: height change from post-op (at discharge) height Result at 24 mos (randomized cohort): − 0.41 mm ± 0.427 mm Result at 24 mos (training cohort): − 0.45 mm ± 0.336 mm | Assessment criteria: device motion ≥ 3 mm (cranial/caudal for subsidence, anterior/posterior for migration) Subsidence at 24 mos: 0 Migration at 24 mos: 0 | Assessment criteria (radiographic failure): evidence of continuous bridging bone and < 2° total angular motion (from flexion to extension) Reported as a part of overall success/failure |
Mobi-C (two-level) August 2013 | 234 (225 randomized, 9 training) | 6 weeks, 3-, 6-, 12-, 18-, 24-months and annually thereafter | Assessment criteria: Graded 0–IV per Mehren classification Result at 24 mos: Grade 0: Sup. 23/225 (10.2%); Inf. 20/225 (8.9%) Grade I: Sup. 15/225 (6.7%); Inf. 7/225 (3.1%) Grade II: Sup. 161/225 (71.6%); Inf. 162/225 (72.0%) Grade III: Sup. 17/225 (7.6%); Inf. 17/225 (7.6%) Grade IV: Sup. 8/225 (3.6%); Inf. 6/225 (2.7%) AE reports Occurance at 24 mos: 6/234 patients (2.6%), 6 events Occurance at 60 mos: 13/234 patients (5.6%), 13 events | Assessment criteria: categorized as none, mild (< 25%), moderate (25–50%), or severe (> 50%) Result at 24 mos: mild radiolucency in 2 (1.3%) | Assessment criteria: height change from 6-week post-op height Result at 24 mos (superior): − 0.43 ± 0.398 mm Result at 24 mos (inferior): − 0.35 ± 0.385 mm | Assessment criteria: device motion ≥ 3 mm (cranial/caudal for subsidence, anterior/posterior for migration) Subsidence at 24 mos: 0 Migration at 24 mos: 1 | Assessment criteria (radiographic failure): evidence of continuous bridging bone and < 2° total angular motion (from flexion to extension) Reported as a part of overall success/failure |
Prestige LP (one-level) July 2014 | 280 | 6 weeks, 3-, 6-, 12-, 24-months and annually thereafter | Assessment criteria: reported as bone bridging (criteria comparable to Class IV HO assessment per Mehren) Evidence of bridging at 24 mos: 16/280 (5.9%) AE reports Occurance at 24 mos: 27/280 subjects (9.6%), 31 events | Assessment criteria: NR Reported as part of Radiographic Success | Assessment criteria: maintenance of height (height change ≤ 2 mm from 6-week post-op height) Result at 24 mos: 205/224 (91.5%) | NR | Assessment criteria: evidence of bone spanning the two vertebral bodies, existence of angular motion stability < 4°, and no radiolucent lines covering more than 50% of the implant surface Success at 24 mos: 219/316 (69.3%) |
Prestige LP (two-level) July 2016 | 209 | 6 weeks, 3-, 6-, 12-, 24-months and annually thereafter until last subject enrollment (36-, 60-, 84-, and 120- months) | Assessment criteria: Graded 0–IV per Mehren classification Result at 24 mos: Grade 0: Sup. 143/198 (72.2%); Inf. 126/198 (63.6%) Grade I: Sup. 10/198 (5.1%); Inf. 11/198 (5.6%) Grade II: Sup. 13/198 (6.6%); Inf. 22/198 (11.1%) Grade III: Sup. 28/198 (14.1%); Inf. 33/198 (16.7%) Grade IV: Sup. 4/198 (2.0%); Inf. 6/198 (3.0%) Bone bridging comparable to Class IV HO also reported AE reports Occurance ≤ 24 months: 22/209 subjects (10.5%), 27 events Occurance ≤ 84 months: 33/209 subjects (15.8%), 40 events | Assessment criteria: NR Reported as part of Radiographic Success | Assessment criteria: maintenance of height (height change ≤ 2 mm from 6-week post-op height at both treated levels) Result at 24 mos: 159/170 (93.5%) | AE reports Displacement: ≤ 24 Months: 6/209 subjects (2.9%), 6 events ≤ 84 Months: 7/209 subjects (3.3%), 7 events Subsidence: ≤ 24 Months: 2/209 subjects (1.0%), 3 events ≤ 84 Months: 3/209 subjects (1.4%), 4 events Loosening: ≤ 24 Months: 0/209 subjects (0.0%) ≤ 84 Months: 0/209 subjects (0.0%) | Assessment criteria: angular motion on lateral flexion/extension radiographs > 4° but ≤ 20° and no radiographic evidence of bridging trabecular bone that forms a continuous bony connection with the vertebral bodies (i.e., no bridging bone) at both treated levels Success at 24 mos (superior): 137/197 (69.5%) Success at 24 mos (inferior): 126/195 (64.6%) Success at 24 mos (both levels): 100/196 (51.0%) |
M6-C (one-level) February 2019 | 160 | 6 weeks, 3-, 6-, 12-, 24-months and annually thereafter | Assessment criteria: Graded 0-IV per Mehren classification Result at 24 mos: Grade 0: 61/150 (40.7%) Grade I: 22/150 (14.7%) Grade II: 50/150 (33.3%) Grade III: 16/150 (10.7%) Grade IV: 1/150 (0.7%) | Assessment criteria: categorized as none, mild (< 25%), moderate (25–50%), or severe (> 50%) Result at 24 mos: None: 144 (96.0%) Mild (< 25%): 6 (4.0%) Moderate (25–50%): 0 (0.0%) Severe (> 50%): 0 (0.0%) | Assessment criteria: disc height comparison from pre-op height Height preoperatively: 3.22 ± 0.73 mm Height at 24 months: 5.31 ± 1.02 mm | Assessment criteria: NR Loosening at 24 mos: 4/150 (2.6%) Subsidence at 24 mos: 1/150 (0.7%) Migration at 24 mos: 0/150 (0.0%) | NR |
Simplify (one-level) September 2020 | 166 (150 randomized, 16 training) | 6 weeks, 3-, 6-, 12-, 24-months and annually thereafter | Assessment criteria: Graded 0–IV per Mehren classification Results at 24 mos: Grade 0: 20/139 (14%) Grade I: 16/139 (12%) Grade II: 80/139 (58%) Grade III: 11/139 (8%) Grade IV: 10/139 (7%) | NR | Assessment criteria: disc height comparison from pre-op height Height preoperatively: 3.31 ± 0.74 Height at 24 months: 4.24 ± 0.94 mm Superior and inferior adjacent level height also reported | Assessment criteria: device motion > 3 mm compared to position at implantation Migration at 24 months: 0 AE reports Implant collapse or Subsidence through Day 790: 0 | NR |
Simplify (two-level) April 2021 | 200 (182 randomized, 18 training) | 6 weeks, 3-, 6-, 12-, 24-, 36-months and annually thereafter | Assessment criteria: Graded 0–IV per Mehren classification Results at 24 mos: Grade 0: 21/166 (13%) Grade I: 21/166 (13%) Grade II: 106/166 (64%) Grade III: 8/166 (5%) Grade IV: 8/166 (5%) | NR | Assessment criteria: height change from post-op height Result at 24 months: Superior component: 1.19 ± 0.81 mm Inferior component: 0.84 ± 0.96 mm Superior and inferior adjacent level height also reported Assessment criteria for disc height success also reported but with no corresponding results | Assessment criteria: device motion > 3 mm compared to position at implantation Migration at 24 months: 0 AE reports Implant collapse or Subsidence through Day 790: 0 | NR |