Table 2.
Clinical studies included in the systematic review. Summary of the most important aspects taken into consideration for the results description: type and follow-up of the study, cages used for spinal fusion surgery, complications encountered, main results, and references. The studies were also grouped according to the performed surgical procedure.
| Study Type (f-up) |
Cages (no. of pz) |
Systemic and Local Complications | Fusion Results | Clinical Score Results | Ref. |
|---|---|---|---|---|---|
| Posterolateral lumbar interbody fusion (PLIF) 1-, 2- or 3-level PLIF | |||||
| Randomized study (24 mo) | PEEK cage (35 pz), ABG (34 pz) |
PEEK cage and ABG: dural tears. PEEK cage: superficial wound infection, no cage loosening or breaking |
PEEK cage and ABG: ↑ fusion rate, mean disc height |
PEEK cage and ABG: ↓ pain, VAS score with good functional outcomes | [19] |
| Prospective, nonrandomized, controlled study (mean 32 mo) | PEEK cage + ABG (173 pz), Biocage (206 pz) |
PEEK cage + ABG: similar operation time, blood loss, LOS, pseudoarthrosis, subsidence, delayed incision healing to Biocage |
PEEK cage + ABG and Biocage: ↑ fusion rate. PEEK cage: ↓ mean height of intervertebral space recovery, height of intervertebral foramen recovery compared to Biocage |
PEEK cage + ABG and Biocage: ↓ VAS, ODI | [20] |
| Prospective, uncontrolled study (12 mo) | PEEK + βTCP + BMA cage (34 pz) | Blood loss, transient paresis L5, dura leakage, migration of cage, seroma, inadequate fusion | ↑ fusion rate | ↓ ODI, VAS | [21] |
| Transforaminal lumbar interbody fusion (TLIF) 1-or multi-level TLIF | |||||
| Retrospective study (24 mo) | PEEK cage + ABG (40 pz), Ti cage + ABG (77 pz) |
PEEK cage + ABG: pseudoarthrosis at 10 level. Ti cage + ABG: pseudoarthrosis at 16 level |
PEEK cage + ABG: similar bone union rate to Ti cage + ABG | / | [22] |
| Observational, prospective, nonrandomized cohort study (24 mo) | PEEK + silicon cage added with Ti screw (22 pz) | LOS, pulmonary disease. Material failure in the dynamic portion, revision surgery, lumbar radiculopathy with no neurological deficit, misplaced pedicle screw and revision surgery, superficial wound infection, incidental durotomy |
/ | ↓ COMI, VAS scores | [23] |
| Randomised controlled clinical pilot trial (12 mo) | PEEK cage (20 pz), TiPEEK cage (20 pz) |
PEEK cage: similar revision for pseudoarthrosis, loose pedicle screws, i.o. hematoma to TiPEEK cage. TiPEEK cage: persistent leg pain, p.o. wound infection |
PEEK and TiPEEK cages: ↑ fusion rate, preservation of disc height in the fused or adjacent segments |
PEEK and TiPEEK cages: ↓ ODI score, ↑ EQ-5D. TiPEEK cage: ↑ VAS leg pain compared to PEEK cage |
[24] |
| Anterior lumbar interbody fusion (ALIF) 1-, 2-, 3-level ALIF | |||||
| Prospective, randomized, controlled clinical trial (12 mo) | PEEK + βTCP + BMA cage (50 pz) | Blood loss, paresis L5, hematoma, vessel lesions, migration of cage, pseudoarthrosis, inadequate fusion anteriorly | ↑ fusion | ↓ ODI, VAS | [25] |
| Prospective, uncontrolled study (mean 12 mo) | PEEK + rhBMP-2 cage (131 pz) | Minor complications. Major complications, prolonged pseudo-obstruction of the colon, DVT, bilateral pleural effusions, aspiration pneumonia, UTI. Pseudoarthrosis |
↑ interbody fusion | ↓ ODI, VAS, ↑ SF-36 PCS and SF-36 MCS | [26] |
| Extreme lateral interbody fusion (XLIF) | |||||
| Retrospective study (24 mo) | PEEK + βTCP + HA cage (25 pz), PEEK + rhBMP-2 cage (110 pz) |
PEEK + rhBMP-2 cage: hematoma. PEEK + βTCP + HA cage: similar radiculopathy, subsidence, superficial wound infection to PEEK + rhBMP-2 cage |
PEEK + rhBMP-2 cage: ↑ fusion rate compared to PEEK + βTCP + HA cage | PEEK + βTCP + HA and PEEK + rhBMP-2 cages: ↓ ODI, VAS, ↑ SF-36 PCS, SF-36 MCS | [27] |
| Anterior cervical discectomy and fusion (ACDF) 1- and 2-level ACDF | |||||
| Retrospective analytical observational cohort study | PEEK + ABG cage (30 pz), ABG (30 pz) |
PEEK + ABG cage: ↓ operation time compared to ABG. ABG: donor site chronic pain, surgical wound infection, reoperation due to broken fixation system screw |
PEEK + ABG cage and ABG: ↑ fusion rates, recovery of disc space height. PEEK + ABG cage: similar fusion rate as ABG |
PEEK + ABG cage and ABG: ↑ clinical results | [28] |
| / (24 mo) |
PEEK + ABG cage (29 pz), ABG (31 pz) |
PEEK + ABG cage: ↓ operation time, blood loss, perioperative complications compared to ABG. PEEK + ABG cage: dysphagia. ABG: donor site pain, dysphagia, wound infections |
PEEK + ABG cage and ABG: ↑ fusion rate. PEEK + ABG cage: similar fusion rate as ABG |
PEEK + ABG cage and ABG: ↓ VAS, ↑ JOA score. PEEK + ABG cage: ↓ DSH than ABG |
[29] |
| Prospective study (24 mo) | PEEK + ABG cage (28 pz) |
4-level ACDF: ↑ operation time, bleeding compared to 2- and 3-level ACDF. 2-, 3- and 4-level ACDF: Transient dysphagia, subsidence. 3- and 4-level ACDF: significant dysphagia, pseudoarthrosis rate, transient donor site pain |
2-, 3- and 4-level ACDF: ↑ solid fusion | 2-, 3- and 4-level ACDF: ↓ VAS, excellent and good results | [30] |
| Retrospective study (mean 29 mo) | Self-locking PEEK + bioceramic artificial bone cage with or without plate fixation (54 pz) | Mild dysphagia. Mild pseudoarthrosis |
With and without plate fixation: ↑ fusion rate | With and without plate fixation: ↑ NDI, JOA | [31] |
| Prospective, single-blind randomized controlled study (24 mo) | PEEK + ABG cage (48 pz), Silicon nitride + blood cage (52 pz) |
PEEK + ABG cage: similar operation time, blood loss, LOS, transient dysphagia, subsidence, incidental durotomy, recurrent symptomatic nerve root compression as silicon nitride + blood cage. PEEK + ABG cage: ↓ revision surgery at the adjacent level than silicon nitride + blood cage |
PEEK + ABG and silicon nitride + blood cages: ↑ fusion rate | PEEK + ABG and silicon nitride + blood cages: ↑ NDI, SF36, patient perceived recovery, ↓ VAS | [32] |
| Retrospective study (mean 96.4 mo) | PEEK + ABG cage (47 pz), nHA/PA66 + ABG cage (51 pz) |
PEEK + ABG cage: similar wound infection, subsidence to nHA/PA66 + ABG cage |
PEEK + ABG and nHA/PA66 + ABG cages: ↑ fusion rate, segmental lordosis. PEEK + ABG cage: similar fusion rate as nHA/PA66 + ABG cage |
PEEK + ABG and nHA/PA66 + ABG cages: ↑ JOA score, ↓ VAS score, good clinical outcome. | [33] |
| Prospective, randomized, controlled clinical study (24 mo) | PEEK + ABG cage (33 pz), PEEK + CS/DBM cage (35 pz) |
PEEK + ABG cage: ↑ operation time, blood loos, total complication rate compared to PEEK + CS/DBM cage. PEEK + ABG cage: similar LOS, minor complications, hoarseness, superficial wound infection as PEEK + CS/DBM cage |
PEEK + ABG and PEEK + CS/DBM cages: ↑ fusion rate. PEEK + ABG cage: similar fusion rate as PEEK + CS/DBM cage |
PEEK + ABG and PEEK + CS/DBM cages: ↓ VAS, ↑ JOA score | [34] |
| Retrospective study (mean 30 mo) | PEEK + ABG cage (23 pz), PEEK + PolyBone cage (24 pz) |
PEEK + ABG cage: similar operation time as PEEK + PolyBone cage |
PEEK + ABG and PEEK + PolyBone cages: ↑ fusion rate. PEEK + PolyBone cage: ↓ disc height, ↑ time taken for fusion compared to PEEK + ABG cage |
PEEK + ABG and PEEK + PolyBone cages: ↓ NDI, NRS score | [35] |
| Prospective, single-blind, randomized, controlled clinical study (12 mo) | PEEK + βTCP cage (32 pz), Acrylic cage (32 pz) |
PEEK + βTCP cage: similar transient hoarseness, new degenerative changes at each level of the cervical spine, disk herniation at lower level compared to acrylic cage |
PEEK + βTCP cage: ↓ fusion rate, disc space height compared to acrylic cage. PEEK + βTCP cage: similar subsidence as acrylic cage |
PEEK + βTCP cage: ↓ clinical outcomes compared to acrylic cage | [36] |
| Retrospective chart review (median 12 mo) | PEEK + βTCP cage (107 pz), PEEK + rhBMP2 cage (84 pz) |
PEEK + βTCP cage: ↓ 30-day readmission, oral steroids compared to PEEK + rhBMP2 cage. PEEK + βTCP cage: similar LOS, postoperative neurologic deficit, any dysphagia, ICU asPEEK + rhBMP2 cage. PEEK + βTCP cage: hardware failures. PEEK + βTCP cage: ↑ subsequent cervical spine surgery compared to PEEK + rhBMP2 cage |
PEEK + βTCP cage: ↓ fusion rate compared to PEEK + rhBMP2 cage | / | [37] |
| Prospective single senior surgeon cohort study (mean 14.6 mo) | PEEK + Ti alloy + allograft cage (24 pz) | Without anterior plate fixation: pseudoarthrosis | With and without anterior plate fixation: ↑ fusion rate | With and without anterior plate fixation: ↑ MCS, ↓ VAS, good and excellent clinical outcomes | [38] |
| Retrospective cohort study (mean 24 mo) | Non-Plasmapore-coated Ti cage (42 pz), Ti cage coated with Plasmapore (30 pz) |
None-Plasmapore-coated Ti cage: similar blood loss, operation time as Ti cage coated with Plasmapore | Non-Plasmapore-coated Ti cage and Ti cage coated with Plasmapore: ↑ solid fusion rate | / | [39] |
↑ = increased; ↓ = reduced; ABG = autologous bone graft; ACDF = anterior cervical discectomy and fusion; BMA = bone marrow aspirate; COMI = Core Outcome Measures Index; CS/DBM = calcium sulphate/demineralized bone matrix; DSH = disc space heights; DVT = deep venous thrombosis;; f-up = follow-up; HA = hydroxyapatite; ICU = intensive care unit; JOA = Japanese Orthopaedic Association; LOS = length of stay in hospital; MCS = Mental Health Component Summary; mo = month; NDI = Neck Disability Index; NRS = numeric rating scale; ODI = Oswestry dysfunction index; PA66 = polyamide 66; PEEK = Polyetheretherketone; pz = patients; Ref. = reference; rhBMP-2 = recombinant human bone morphogenetic protein 2; SF-36 MCS = Short Form 36 mental component summary; SF-36 PCS = Short Form 36 physical component summary; Ti = titanium; UTI = urinary tract infection; VAS = Visual Analog Scale; yrs = years; βTCP = beta tricalcium phosphate.