Table 2.
Study characteristics of selected RCTs (significant results in bold; figures show first interventional group and second comparator)
| References | Murrey [14] | Heller [10] | Cheng [5] | Anderson [1] | Mummaneni [13] | Nabhan [15] | Robertson [17] |
|---|---|---|---|---|---|---|---|
| Country | USA (FDA) multicentre study | USA (FDA) multicentre study | China | USA (FDA) multicentre study | USA (FDA) multicentre study | G | USA |
| Sponsor | Synthes | Medtronic | n.s. | Medtronic | Medtronic | n.s. | Medtronic |
| Product | ProDisc-C | Bryan Cervical disc | Bryan Cervical disc | Bryan Cervical disc | Prestige St Cervical disc | ProDisc-C | Bryan Cervical disc |
| Comparator | ACDF | ACDF + plate | ACDF (+plate) | ACDF + plate | ACDF | ACDF + cage + plate | ACDF + plate |
| Study design | RCT (non-inferiority) | RCT (non-inferiority) | RCT | RCT (non-inferiority) | RCT (non-inferiority) | RCT | RCT + non-comparative registry |
| Number of patients randomised | 209 (103/106) | 582 (290/292) | 65 (31/34) | 463 (242/221) | 625 (313/312) | 49 (25/24) | 305 (103/202) |
| Age of patients (included min/max age) | Ø 42/44 (18–60) | Ø 44/47 (25–78) | Ø 45/47 | n.s. | Ø 43/44 (22–73) | Ø 40 | Ø 56/45 (28–81) |
| Discs per patient | 1 | 1 | 2 | 1 | 1 | 1 | 1 |
| Follow up (months) | 24 | 24 | 24 | 24 | 24 | 36 | 24 |
| Outcome year 1 | |||||||
| NDI | n.s. | −36.6/−31.4 (p0.007) | −38/−33 (p0.03) | n.a. | −34.8/−32.8 (p 0.89) | n.a. | n.a. |
| Pain VAS | |||||||
| Neck pain | n.s. | −51.8/−46.7 (p0.04) | −5.4/−4.6 | n.a. | Figures n.s. | −4.2/−4.2 (p n.s.) | n.a. |
| Arm pain | −54.7/−49.9 (p0.03) | −5.3/−4.8 (p n.s.) | −5.9/−5.7 (p n.s.) | ||||
| SF 36 | |||||||
| Physical component | 81%/76.7%c (p 0.3) | +15.8/+13.7 (p0.010) | +14/+ 12 | n.a. | +12.8/+11.2 (not s.) | n.a. | n.a. |
| Mental component | +10.2/+7 (p0.048) | n.s. | +7.7/+6.1 (not s.) | ||||
| Overall success (OS) | n.a. | n.a. | n.a. | n.a. | 77.6%/66.4% (p0.004) | n.a. | n.a. |
| Satisfaction | n.s. | n.a. | n.a. | n.a. | n.a. | n.a. | n.a. |
| Outcome year 2 | |||||||
| NDI | 79.8%/78.3%a (not s.) | 86%/78.9%a (p0.035) | −39/−32 (p0.023) | n.a. | −36/−33.6 (p 0.08) | n.a. | n.a. |
| Pain VAS | |||||||
| Neck pain | 87.9%/86.9%d (p 1.0) | −52.8/−44.5 (p0.009) | −5.8/−4.5 (p0.012) | n.a. | Figures n.s. | −4.2/−3.5 (p n.s.) | n.a. |
| Arm pain | −52.17/−49.7 (p 0.194) | −5.7/−4.5 (p0.013) | −6.1/−5.3 (p n.s.) | ||||
| SF 36 | |||||||
| Physical component | +15.3/+14.5 (p 0.15) | +15/+11 (p0.013) | n.a. | +13.1/+11.8 (not s.) | n.a. | n.a. | |
| Mental component | +9.4/+7.1 (p 0.27) | n.s. | +7.4/+7.5 (not s.) | ||||
| Overall | 79.2%/70%c (p 0.09) | ||||||
| Neurological successb | 90.9%/88% (p 0.638) | 93.9%/90.2% (p 0.1) | n.s. | n.a. | 92.8%/84.3% (p0.006) | n.a. | n.a. |
| Overall success (OS) | 72.3%/68.3% (p0.01 non-inf.) | 82.6%/72.7% (p0.001 non-inf.; p0.01 superior) | n.a. | n.a. | 79.3%/67.8% (p0.004 non-inf.; p0.0053 superior) |
n.a. | n.a. |
| 72.7%/60.4%e (p0.047) | |||||||
| Satisfaction | 83.4/80 (not s.) | n.s. | n.a. | n.a. | n.a. | n.a. | |
| Employment | |||||||
| Employment rate | 83%/80% (p 0.71) | 76.8%/73.6% (not s.) | n.a. | n.a. | 75.4%/74.7% (p n.s.) | n.a. | n.a. |
| Return to work time | 48 days/61 days (p0.004) | 45 days/61 days (p0.022) | |||||
| Outcome year 3 | |||||||
| Pain VAS | |||||||
| Neck pain | n.a. | n.a. | n.a. | n.a. | n.a. | −4.3/−3.7 (p 0.06) | n.a. |
| Arm pain | −6.1/−5.5 (p 0.1) | ||||||
| Drop-out rate | 2 (103)/6 (106) | 60 (290)/98 (292) | 1 (31)/2 (34) | 10% | 91 (313)/115 (312) [3] | 6 (25)/3 (24) | 29 (103)/44 (202) |
| Complications | |||||||
| SSP | 2 (103)/9 (106) | 6 (242)/8 (290) (not s.) | 13 (242)/17 (221) (p0.045) | 5 (276)/23 (265) | n.s. | ||
| IAE | 3 (103)/7 (106) | 2.9%/5.4% | |||||
| SAE | 1.7%/3.2% | 32 (242)/47 (221) | |||||
| GAE | 1 (31)/1 (34) | 82 (242)/64 (221) (p0.023) | 17 (276)/11 (265) | ||||
| ME | 36 (242)/34 (221) (p 0.07) | ||||||
| SADD | 0 (103)/1 (106) | 3 (276)/9 (265) (p 0.07) | 0 (158)/11 (74) (p0.018) | ||||
ACDF anterior cervical discectomy and fusion, CH Switzerland, F France, G Germany, GAE general adverse events, IAE implant or implantation-related serious adverse event (fatal, life threatening, requires hospitalisation, prolongation of hospitalisation, results in persistent or significant disability/incapacity or requires medical/surgical intervention), n.a. not applicable, ME medical events possibly or directly related to operation, NDI neck disability index, non-inf. non-inferiority hypothesis, n.s. not stated, not s. not significant, OS ≥15-point improvement in NDI, no serious adverse events, no additional surgical procedure [13] (maintenance/improvement in neurological parameters) [10, 14], SADD symptomatic adjacent disc disease, SF-36 Short form 36 (mental and physical health survey), SAE serious adverse events (WHO grade 3 + 4) related to implant or operation, SSP secondary surgery procedure (revision, removal or re-operation), VAS visual analogue scale
a>15-point improvement
bMaintenance or improvement in sensory, motor and reflex functions
cAny improvement from baseline
d20% improvement in arm or neck pain
eMinimum clinically important difference hypothesis