Polyetheretherketone Cage Research Articles

Does Preoperative Modic Changes Influence the Short-term Fusion Rate of Single Level Transforaminal Lumbar Interbody Fusion?-a Matched-pair Case Control Study.

At present, the influence of Modic changes (MCs) on postoperative fusion rate of lumbar interbody fusion (LIF) is mainly focused on the medium- and long-term fusion rate, while the short-term fusion rate has not been reported. The aim of this study was to compare the short-term fusion rate of lumbar degenerative disease patients with and without MCs after single level transforaminal lumbar interbody fusion (TLIF). In this retrospective and matched-pair case control study, we included 100 patients who underwent TLIF from January 2017 to January 2020 and had at least two follow-up visits over a two-year period. Fifty patients with MCs (MCs group) were matched with 50 patients without MCs (non MCs group) for age, sex, surgical level, diagnosis, operative time, and intraoperative blood loss. We collected the X-ray and computed tomography (CT) data of patients from 3 months to 2 years after the operation to assess bony fusion and the cage union ratio. According to the type of cage, the MCs group was further divided into the nano-hydroxyapatite/polyamide 66 (n-HA/PA66) group and polyetheretherketone (PEEK) group, and the fusion performance between the two groups was compared. Finally, age, sex, body mass index (BMI), smoking and cage type were included in the logistic regression model for risk factor analysis. The bony fusion rates in the MCs group at 3 months, 6 months, 1 year and 2 years after surgery were significantly lower than those in the non MCs group (P < 0.05) (23.8% vs 62.5%, 52.6% vs 78.9%, 61.1% vs 83.3%, 74.0% vs 90.0%). The average coronal cage union ratios of the upper and lower endplates in the MCs group were significantly lower than those in the non MCs group (54.3% ± 17.5% vs 75.0% ± 17.2%, P < 0.05; 73.3% ± 12.0% vs 84.9% ± 8.0%, P < 0.05). Similarly, analogous results were obtained by comparing the MCs and non MCs groups' three-dimensional CT sagittal plane images (62.5% ± 16.5% vs 76.1% ± 12.4%, P < 0.05; 67.0% ± 13.9% vs 79.8% ± 11.5%, P < 0.05). Short-term fusion rates were lower in the MCs group than in the non MCs group. The coronal and sagittal cage union ratio in the MCs group was lower than that in the non MCs group. The fusion performance of n-HA/PA66 and PEEK cages in the MCs group was comparable.

Posterior Reduction and Intra-Articular Cage Fusion With a C2 Nerve Root Preservation Technique for Treating Posterior Atlantoaxial Dislocation Secondary to Os Odontoideum.

Posterior C1-C2 interlaminae compression fusion with iliac bone graft may lead to donor site complications and recurrent C1 posterior dislocation for posterior atlantoaxial dislocation (AAD) secondary to os odontoideum. C1-C2 intra-articular fusion often needs C2 nerve ganglion transection to facilitate exposing and manipulating the facet joint, leading to bleeding from the venous plexus and suboccipital numbness or pain. Therefore, this study was conducted to evaluate the outcomes of posterior C1-C2 intra-articular fusion with a C2 nerve root preservation technique in the treatment of posterior AAD secondary to os odontoideum. Data of the 11 patients who underwent C1-C2 posterior intra-articular fusion because of posterior AAD secondary to os odontoideum were retrospectively reviewed. Posterior reduction was performed using C1 transarch lateral mass screws and C2 pedicle screws. Intra-articular fusion was performed using a polyetheretherketone cage filled with autologous bone from the caudal edge of the C1 posterior arch and cranial edge of the C2 laminar. Outcomes were evaluated by using the Japanese Orthopaedics Association score, Neck Disability Index, and visual analog scale for neck pain. Bone fusion was evaluated by using computed tomography and 3-dimensional reconstruction. The average follow-up duration was 43.9 ± 9.5 months. All patients achieved good reduction and bone fusion, without transection of the C2 nerve roots. The mean bone fusion time was 4.3 ± 1.1 months. There was no complication related to the surgical approach and instrumentation. Function of the spinal cord manifested by the Japanese Orthopaedics Association score significantly improved ( P < .05). The Neck Disability Index score and visual analog scale for neck pain markedly decreased (all P < .05). Posterior reduction and intra-articular cage fusion with a C2 nerve root preservation technique was a promising treatment of posterior AAD secondary to os odontoideum.

Comparison of Fusion, Subsidence, and Clinical Results Between 3D-Printed Porous Titanium Cage and Polyetheretherketone Cage in Posterior Lumbar Interbody Fusion: A Minimum of 2 Years Follow-Up

The occurrence of early osteointegration and reduced modulus of elasticity have been proved with 3-dimensinally (3D) printed porous titanium (3DP-titanium) cages used for posterior lumbar interbody fusion (PLIF). The present study was conducted to demonstrate the fusion rate, subsidence, and clinical outcomes for the 3DP-titanium cage in PLIF and to compare its results with those of the polyetheretherketone (PEEK) cage. A total of 150 patients who underwent 1-2-level PLIF and were followed up for >2 years were retrospectively reviewed. The fusion rates, subsidence, segmental lordosis, visual analog scale (VAS) score for back pain, VAS score for leg pain, and Oswestry disability index were assessed. A higher 1-year (3DP-titanium, 86.9%; PEEK, 67.7%; P= 0.002) and 2-year (3DP-titanium, 92.9%; PEEK, 82.3%; P= 0.037) fusion rate could be achieved with 3DP-titanium cages for PLIF than with PEEK cages. The amount of subsidence (3DP-titanium, 1.4 ± 1.6 mm; PEEK, 1.9 ± 1.8 mm; P= 0.092) and incidence of significant subsidence (3DP-titanium, 17.9%; PEEK, 23.4%; P= 0.389) was not significantly different between the 2 materials. Furthermore, the VAS score for back pain and leg pain and Oswestry disability index were not significantly different between the 2 groups. On logistic regression analysis, cage material (P= 0.027) showed a significant association with fusion, and the number of levels fused (P= 0.012) was associated with subsidence. The 3DP-titanium cage resulted in a higher fusion rate than the PEEK cage when used for PLIF. The subsidence rate did not differ significantly between the 2 cage materials. Therefore, the 3DP-titanium cage can be safely used for PLIF, considering its stable construct.

Three-Dimensional-Printed Titanium Versus Polyetheretherketone Cages for Lumbar Interbody Fusion: A Systematic Review of Comparative In Vitro, Animal, and Human Studies.

Interbody fusion is a workhorse technique in lumbar spine surgery that facilities indirect decompression, sagittal plane realignment, and successful bony fusion. The 2 most commonly employed cage materials are titanium (Ti) alloy and polyetheretherketone (PEEK). While Ti alloy implants have superior osteoinductive properties they more poorly match the biomechanical properties of cancellous bones. Newly developed 3-dimensional (3D)-printed porous titanium (3D-pTi) address this disadvantage and are proposed as a new standard for lumbar interbody fusion (LIF) devices. In the present study, the literature directly comparing 3D-pTi and PEEK interbody devices is systematically reviewed with a focus on fusion outcomes and subsidence rates reported in the in vitro, animal, and human literature. A systematic review directly comparing outcomes of PEEK and 3D-pTi interbody spinal cages was performed. PubMed, Embase, and Cochrane Library databases were searched according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) guidelines. Mean Newcastle-Ottawa Scale score for cohort studies was 6.4. A total of 7 eligible studies were included, comprising a combination of clinical series, ovine animal data, and in vitro biomechanical studies. There was a total population of 299 human and 59 ovine subjects, with 134 human (44.8%) and 38 (64.4%) ovine models implanted with 3D-pTi cages. Of the 7 studies, 6 reported overall outcomes in favor of 3D-pTi compared to PEEK, including subsidence and osseointegration, while 1 study reported neutral outcomes for device related revision and reoperation rate. Though limited data are available, the current literature supports 3D-pTi interbodies as offering superior fusion outcomes relative to PEEK interbodies for LIF without increasing subsidence or reoperation risk. Histologic evidence suggests 3D-Ti to have superior osteoinductive properties that may underlie these superior outcomes, but additional clinical investigation is merited.

Commentary on "Three-Dimensional-Printed Titanium Versus Polyetheretherketone Cages for Lumbar Interbody Fusion: A Systematic Review of Comparative In Vitro, Animal, and Human Studies".

Commentary on "Three-Dimensional-Printed Titanium Versus Polyetheretherketone Cages for Lumbar Interbody Fusion: A Systematic Review of Comparative In Vitro, Animal, and Human Studies".

Early Experience With Uniplanar Versus Biplanar Expandable Interbody Fusion Devices in Single-Level Minimally Invasive Transforaminal Lumbar Interbody Fusion.

To compare the early radiographic and clinical outcomes of expandable uniplanar versus biplanar interbody cages used for single-level minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF). A retrospective review of 1-level MIS-TLIFs performed with uniplanar and biplanar polyetheretherketone cages was performed. Radiographic measurements were performed on radiographs taken preoperatively, at 6-week follow-up, and 1-year follow-up. Oswestry Disability Index (ODI) and visual analogue scale (VAS) for back and leg at 3-month and 1-year follow-up. A total of 93 patients (41 uniplanar, 52 biplanar) were included. Both cage types provided significant postoperative improvements in anterior disc height, posterior disc height, and segmental lordosis at 1 year. No significant differences in cage subsidence rates were found between uniplanar (21.9%) and biplanar devices (32.7%) at 6 weeks (odds ratio, 2.015; 95% confidence interval, 0.651-6.235; p = 0.249) with no additional instances of subsidence at 1 year. No significant differences in the magnitude of improvements based on ODI, VAS back, or VAS leg at 3-month or 1-year follow-up between groups and the proportion of patients achieving the minimal clinically important difference in ODI, VAS back, or VAS leg at 1 year were not statistically significantly different (p > 0.05). Finally, there were no significant differences in complication rates (p = 0.283), 90-day readmission rates (p = 1.00), revision surgical procedures (p = 0.423), or fusion rates at 1 year (p = 0.457) between groups. Biplanar and uniplanar expandable cages offer a safe and effective means of improving anterior disc height, posterior disc height, segmental lordosis, and patient-reported outcome measures at 1 year postoperatively. No significant differences in radiographic outcomes, subsidence rates, mean subsidence distance, 1-year patient-reported outcomes, and postoperative complications were noted between groups.

Comparing the Effectiveness and Safety of Anterior Cervical Discectomy and Fusion with Four Different Fixation Systems: A Systematic Review and Network Meta-analysis

Background: Anterior cervical discectomy and fusion (ACDF) is the classic procedure for the treatment of degenerative cervical myelopathy (DCM). Cage with plate (CP), polyetheretherketone cage alone (PCA), ROI-C and Zero-P are the most widely used fixation systems in ACDF. However, there is insufficient evidence to determine the optimal system for ACDF. Purpose: A comprehensive analysis to show which of the CP, PCA, ROI-C and Zero-P after ACDF has the best clinical efficacy and the most reliable safety. Methods: We searched the Embase, Pubmed, and Cochrane library up to the date of February 13th, 2021. Studies included relevant randomized controlled trials (RCTs) and cohort studies with a comparison of different fixation systems among CP, PCA, ROI-C and Zero-P were identified. Results: We screened 43 trials eligible, including 3045 patients. No significant differences were found in the NDI score. PCA has shown a significantly less recovery of cervical lordosis than CP and Zero-P. For the non-fusion rate, PCA was significantly higher than CP. PCA had a significantly higher subsidence rate than CP and Zero-P, and ROI-C was also significantly higher than CP. For the incidence of complications, CP was significantly higher than the others. The surface under the cumulative ranking curves (SUCRA) for NDI score improvement was: SSC, PCA, and CP. ROI-C, Zero-P, PCA, and CP; for cervical lordosis recovery: CP, Zero-P, ROI-C, and PCA; for non-fusion rate: PCA, Zero-P, ROI-C, and CP; for subsidence rate: PCA, ROI-C, Zero-P, and CP; for complications: CP, PCA, ROI-C, and Zero-P. Conclusion: Despite the third-ranking spectrums of fusion rate, Zero-P still could be recommended for its second-ranking spectrums of the NDI score improvement efficacy, cervical lordosis recovery, and reduction of subsidence rate, with the least ranking of complications. Registration: The number of PROSPERO is CRD42021230735 (www.crd.york.ac.uk/PROSPERO).

Anterior Cervical Discectomy and Fusion Performed Using a CaO-SiO2-P2O5-B2O3 Bioactive Glass Ceramic or Polyetheretherketone Cage Filled with Hydroxyapatite/β-Tricalcium Phosphate: A Prospective Randomized Controlled Trial.

A CaO-SiO2-P2O5-B2O3 bioactive glass-ceramic (BGS-7) spacer provides high mechanical stability, produces a chemical bond to the adjacent endplate, and facilitates fusion after spine surgery. This prospective, randomized, single-blind, non-inferiority trial aimed to evaluate the radiographic outcomes and clinical efficacy of anterior cervical discectomy and fusion (ACDF) using a BGS-7 spacer for treating cervical degenerative disorders. Thirty-six patients underwent ACDF using a BGS-7 spacer (Group N), and 40 patients underwent ACDF using polyetheretherketone (PEEK) cages filled with a mixture of hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP) for the treatment of cervical degenerative disorders. The spinal fusion rate was assessed 12 months postoperatively using three-dimensional computed tomography (CT) and dynamic radiographs. Clinical outcomes included patient-reported outcome measures, visual analog scale scores for neck and arm pain, and scores from the neck disability index (NDI), European Quality of Life-5 Dimensions (EQ-5D), and 12-item Short Form Survey (SF-12v2). All participants were randomly assigned to undergo ACDF using either a BGS-7 spacer or PEEK cage filled with HA and β-TCP. The primary outcome was the fusion rate on CT scan image at 12 months after ACDF surgery based on a per-protocol strategy. Clinical outcomes and adverse events were also assessed. The 12-month fusion rates for the BGS-7 and PEEK groups based on CT scans were 81.8% and 74.4%, respectively, while those based on dynamic radiographs were 78.1% and 73.7%, respectively, with no significant difference between the groups. There were no significant differences in the clinical outcomes between the two groups. Neck pain, arm pain, NDI, EQ-5D, and SF-12v2 scores significantly improved postoperatively, with no significant differences between the groups. No adverse events were observed in either group. In ACDF surgery, the BGS-7 spacer showed similar fusion rates and clinical outcomes as PEEK cages filled with HA and β-TCP.

Surface Modification Techniques for Polyetheretherketone as Spinal Interbody Fusion Cage Material to Stimulate Biological Response: A Review

Currently, spinal interbody cages are crucial for spinal fusion surgeries. Due to the mechanical and imaging characteristics of polyetheretherketone (PEEK), it is a widely used material for cages. However, the bioinert PEEK has poor osseointegration, thereby preventing the ideal fusion of PEEK cages. Therefore, efforts have been made for improving biological activity using surface modification techniques, including physical as well as chemical modifications and surface coating. In this study, we reviewed and analyzed recent studies on PEEK surface modification techniques to enhance our understanding for future studies.

Clinical Outcome of Pedicle-Sparing Transfacet Diskectomy and Fusion with Segmental Instrumentation for Thoracic Disc Herniation.

Thoracic disk herniations (TDHs) are relatively rare compared with their cervical and lumbar counterparts. Posterior approaches allow for a simpler and less invasive surgery than anterior and lateral approaches. A pedicle-sparing transfacet approach was initially described in 1995, and modified in 2010. A few clinical series have reported the outcome of this procedure in patients with TDH. This study aimed to evaluate the outcomes and complications of pedicle-sparing transfacet diskectomy with interbody fusion and segmental instrumentation in patients with TDH. Twenty-one consecutive patients with symptomatic TDH referred to our tertiary care center were included in this retrospective study. All patients underwent a pedicle-sparing transfacet diskectomy with polyetheretherketone (PEEK) cage interbody fusion and short segmental instrumentation. Distribution of TDH, operative duration, blood loss, Visual Analog Scale (VAS) pain scores, Nurick grades, modified Japanese Orthopaedic Association (mJOA) scores, and fusion rate were assessed. All patients had single-level herniations. The most common location was T12-L1 (38.1%), followed by T11-T12 (33.3%). All patients were successfully operated on with no cerebrospinal fluid (CSF) leaks or wrong-level surgery. The VAS scores significantly diminished from 4.9 (preoperatively) to 2 (18 months after surgery). The average mJOA score increased from 4.6 to 8.5, and the average Nurick grade decreased from 3.1 to 1.6. All patients reported significant improvement in quality of life relative to their preoperative status. A modified pedicle-sparing transfacet diskectomy combined with PEEK cage interbody fusion and segmental instrumentation offers a safe and less invasive approach for the treatment of TDHs.

Effect of Interbody Composition on the Development of Pseudarthrosis Following Anterior Cervical Discectomy and Fusion.

Retrospective cohort study. To determine if polyetheretherketone (PEEK) or titanium alloy cages increase the rate of pseudarthrosis development or revision surgery rate compared with structural allograft following anterior cervical discectomy and fusion (ACDF) and identify if the cage type results in differences in patient-reported outcome measures (PROMs) versus structural allograft. PEEK and titanium alloy cages have become popular options for ACDF intervertebral spacers. However, while data is beginning to emerge on how cage types affect arthrodesis rates, the effect of their composition on PROMs is less clear. All patients aged >18 years who underwent primary one- to four-level ACDF at a single institution were retrospectively identified. Propensity matching was performed to compare patients' PEEK or titanium alloy cages with structural allograft. Multivariate logistic regression analysis was performed to measure the effect of interbody spacer composition on the likelihood of pseudarthrosis development. Of the 502 patients who received structural allograft and had 1-year postoperative dynamic radiographs, 96 patients were propensity matched to 32 patients who received a PEEK cage, and 162 patients were propensity matched to 54 patients who received a titanium alloy cage. Multivariate logistic regression analysis identified that PEEK cage implants (odds ratio [OR], 3.34; p =0.007) predicted pseudarthrosis development compared with structural allograft implantation. Titanium alloy cage (OR, 1.64; p =0.156) implantation was not predictive of pseudarthrosis. One-year postoperative PROMs were not significantly different between patients who received PEEK or titanium alloy cages and those who received structural allograft (all p >0.05). Compared with structural allograft, receiving a PEEK cage increased the risk of pseudarthrosis development following ACDF, whereas receiving a titanium alloy cage had no significant effect on pseudarthrosis development. One-year postoperative patient-reported outcomes were similar between patients who received structural allograft, PEEK, and titanium alloy interbody spacers.

Titanium‑coated polyetheretherketone cages vs. polyetheretherketone cages in lumbar interbody fusion: A systematic review and meta‑analysis.

Fusion material is one of the key factors in the success of lumbar interbody fusion surgery. The present meta-analysis compared the safety and efficacy of titanium-coated (Ti) polyetheretherketone (PEEK) and PEEK cages. Published literature on the use of Ti-PEEK and PEEK cages in lumbar interbody fusion was systematically searched on Embase, PubMed, Central, Cochrane Library, China National Knowledge Infrastructure and Wanfang databases. A total of 84 studies were retrieved and seven were included in the present meta-analysis. Literature quality was assessed using the Cochrane systematic review methodology. After data extraction, meta-analysis was performed using the ReviewManager 5.4 software. Meta-analysis showed that, compared with that in the PEEK cage group, the Ti-PEEK cage group showed a higher interbody fusion rate at 6 months postoperatively (95% CI, 1.09-5.60; P=0.03) and improved Oswestry Disability Index (ODI) scores at 3 months postoperatively [95% CI, -7.80-(-0.62); P=0.02] and visual analog scale (VAS) scores of back pain at 6 months postoperatively [95% CI, -0.8-(-0.23); P=0.0008]. However, there were no significant differences in intervertebral bone fusion rate (12 months after surgery), cage subsidence rate, ODI score (6 and 12 months after surgery) or VAS score (3 and 12 months after surgery) between the two groups. The results of the meta-analysis showed that the Ti-PEEK group had an improved interbody fusion rate and higher postoperative ODI score in the early postoperative period (≤6 months).

Full-Endoscopic Removal of Migrated and Pseudoarthrotic Lumbar Interbody Cages: Case Reports and Technical Note.

The removal of a lumbar interbody cage in revision spine surgery can be challenging, as there is an increased risk of nerve injury and a protracted outcome. The aim of this study was to evaluate the feasibility and preliminary results of uniportal full-endoscopic surgery for the removal of migrated and/or pseudarthrotic lumbar interbody cages. Three complex revision surgery cases with migrated and pseudarthrotic lumbar interbody cages are presented, and the endoscopic surgical technique is described. The clinical outcome was assessed with a visual analog scale and Oswestry Disability Index (ODI) at 1-, 3-, 6-, and 12-month follow-up, while the radiologic outcome was assessed with pre- and postoperative x-ray and computed tomographic images. Full-endoscopic surgery was performed to extract the interbody cage, bypassing scar tissue of previous surgeries with the trans-Kambin approach. Foraminoplasty with manual reamers and/or a high-speed burr under direct endoscopic vision was performed to ensure the safety of the exiting nerve root during cage extraction. The retrieved cage was replaced with a large footprint, expandable titanium cage using the trans-Kambin approach. In all 3 cases, different types of interbody cages (1 titanium, 2 polyetheretherketone, and 1 expandable titanium cage) were removed under direct endoscopic view. In 1 case, we were only able to partially remove an impacted polyetheretherketone cage from the interbody disc endoscopically. The postoperative outcome significantly (P < 0.05) improved compared with preoperative scores in all 3 cases with a follow-up of 6 and 12 months, respectively. In most cases, lumbar interbody cages can be safely removed with endoscopic surgery with good preliminary clinical outcome. Nonetheless, further clinical research with long-term follow-up is required. Results indicate the feasibility of full-endoscopic removal of migrated and pseudoarthrotic lumbar interbody cages.

Presentation of an intraosseous suspensory fixation technique for pediatric and adult ACL reconstruction

The aim is to present a technique for pediatric and adult ACL reconstruction using an intraosseous suspensory fixation. This technique uses a 4-strands hamstring graft fixed in the femoral tunnel, with a loop locked in a polyetheretherketone (PEEK) cage. The ACLip® device offers an inside-out drilling system and a closer fixation to the joint than an extracortical button fixation. The technique can be easily used both in adults and in skeletally immature patients. The first practical experience shows promising results regarding the safety and the effectiveness of the technique. Level of evidence: IV.

Trabecular Bone Remodeling After Posterior Lumbar Interbody Fusion: Comparison of Three-Dimensional Porous Tantalum and Titanium-Coated Polyetheretherketone Interbody Cages.

Retrospective cohort study. The criteria for determining completion of intervertebral stability after posterior lumbar interbody fusion (PLIF) remain controversial. Several new radiological indicators of bone growth and osteointegration have been established. We compared computed tomography (CT) findings related to osteointegration after PLIF with interbody cages of two different materials and designs. We retrospectively analyzed data from 103 patients who underwent PLIF with three-dimensional porous tantalum (Tn) cages or titanium-coated polyetheretherketone (TiP) cages. CT images obtained 3months and 1year after surgery were examined for trabecular bone remodeling (TBR), cancellous condensation (CC), and vertebral endplate cyst (VEC) formation. The incidences of each finding were compared by cage type, and rates of instrument failure and pseudarthrosis were determined. Three months postoperatively, 87% of the levels with Tn cages exhibited TBR, whereas 96% of those with TiP cages did not (P < .001). Most levels with Tn cages levels exhibited TBR and no CC 3months (81%) and 1 year (94%) after surgery. Although 78% of levels with TiP cages exhibited CC and no TBR 3months after surgery, 59% exhibited both CC and TBR 1 year after surgery. Significantly fewer VECs formed around the Tn cages than around the TiP cages both 3months (P = .002) and 1year (P < .001) after surgery. Implant-related problems occurred at levels that exhibited neither TBR nor CC. The porous tantalum cage may enable intervertebral stability that is comparable to bony fusion soon after surgery.

Biportal Endoscopic Transforaminal Lumbar Interbody Fusion Using Double Cages: Surgical Techniques and Treatment Outcomes.

To describe the surgical techniques and the treatment outcomes of biportal endoscopic transforaminal lumbar interbody fusion (BETLIF) using double cages. This study included 89 patients with 114 fusion segments between July 2019 and May 2021. One pure polyetheretherketone (PEEK) cage and 1 composite titanium-PEEK cage were used for interbody fusion. Clinical outcomes measures included visual analogue scale (VAS) scores for lower back pain and leg pain, Oswestry Disability Index (ODI), and Japanese Orthopedic Association (JOA) scores. Computed tomography (CT) of the lumbar spine 1 year postoperatively was used to evaluate the Bridwell interbody fusion grades. There were significant improvement in VAS for lower back pain from 5.2 ± 3.1 to 1.7 ± 2.1, VAS for leg pain from 6.3 ± 2.5 to 1.7 ± 2.0, ODI from 46.7 ± 17.0 to 12.7 ± 16.1, and JOA score from 15.6 ± 6.3 to 26.4 ± 3.2. The p-values were all < 0.001. The average hospital stay was 5.7 ± 1.1 days. The CT studies available for 60 fusion segments showed successful fusion (Bridwell grade I or grade II) in 56 segments (93.3%). Significant cage subsidence of more than 2 mm was only noted in 3 segments (5.0%). Complications included 1 dural tear, 2 pedicle screws malposition, and 2 epidural hematomas, in which 2 patients required reoperations. BETLIF with double cages provided good neural decompression and a sound environment for interbody fusion with a big cage footprint, a large amount of bone graft, endplate preservation, and segmental stability.

Clinical Efficacy of Autogenous Vertebrae-Filled PEEK Cage in Anterior Cervical Discectomy and Fusion with Instrumentation

This study aimed to investigate the clinical efficacy of the autologous vertebral-filled polyetheretherketone (PEEK) cage in anterior cervical discectomy and fusion with instrumentation (ACDFI). The clinical data of 368 patients who received ACDFI from September 2012 to September 2017 were retrospectively analyzed. Based on the material that filled PEEK cage during the surgery, the patients were divided into two groups, the autologous vertebrate group (n equal to 185) and the autologous iliac group (n equal to 183). The operative time, operative blood loss, postoperative complications in the two groups were recorded and analyzed. The bone graft fusion and postoperative functional outcomes, including scores of modified Japanese Orthopedic Association score (mJOA), Neck Disability Index (NDI), and Visual Analog Scale (VAS) were compared. Patients were followed-up for 14.04 ± 0.98 months. At 6-months follow-up, the rate of spinal fusion was 96.29% (178/185) in the vertebral group and 95.94% (176/183) in the iliac group, with no significant difference between the two groups (p &gt; 0.05). The postoperative VAS, mJOA, and NDI scores were also not significantly different between two groups during the follow-up (p &gt; 0.05). The operative time and blood loss in the vertebral group were significantly less than that of the iliac group (p &lt; 0.01). All patients in the iliac group suffered pain at the iliac donor site, 65 patients suffered numbness, 12 patients had fat liquefaction at donor incision. Meanwhile, all the patients in the vertebral group had no postoperative complications. This study concluded that the autologous vertebrae-filled PEEK cage could achieve the same clinical outcome as the autologous iliac, but have the advantages of shorter operative time, less intraoperative blood loss, and postoperative complications.

Speed and quality of interbody fusion in porous bioceramic Al2O3 and polyetheretherketone cages for anterior cervical discectomy and fusion: a comparative study

BackgroundThe objective of this prospective randomized monocentric study is to compare the speed and quality of interbody fusion of implanted porous Al2O3 (aluminium oxide) cages with PEEK (polyetheretherketone) cages in ACDF (anterior cervical discectomy and fusion).Materials and methodsA total of 111 patients were enrolled in the study, which was carried out between 2015 and 2021. The 18-month follow-up (FU) was completed in 68 patients with an Al2O3 cage and 35 patients with a PEEK cage in one-level ACDF. Initially, the first evidence (initialization) of fusion was evaluated on computed tomography. Subsequently, interbody fusion was evaluated according to the fusion quality scale, fusion rate and incidence of subsidence.ResultsSigns of incipient fusion at 3 months were detected in 22% of cases with the Al2O3 cage and 37.1% with the PEEK cage. At 12-month FU, the fusion rate was 88.2% for Al2O3 and 97.1% for PEEK cages, and at the final FU at 18 months, 92.6% and 100%, respectively. The incidence of subsidence was observed to be 11.8% and 22.9% of cases with Al2O3 and PEEK cages, respectively.ConclusionsPorous Al2O3 cages demonstrated a lower speed and quality of fusion in comparison with PEEK cages. However, the fusion rate of Al2O3 cages was within the range of published results for various cages. The incidence of subsidence of Al2O3 cages was lower compared to published results. We consider the porous Al2O3 cage as safe for a stand-alone disc replacement in ACDF.

Biomechanical analysis of the novel S-type dynamic cage by implementation of teaching learning based optimization algorithm - An experimental and finite element study.

Anterior Cervical Discectomy and Fusion (ACDF) is the most popular and effective procedure for patients with intervertebral disc degeneration, where the degenerated disc is replaced with an interbody implant (widely known as cage). The design of the cage plays a vital role since it has to provide stability for the anterior cervical column without any side-effects. We designed a novel S-type dynamic cage for C4-C5 level, using Polyetheretherketone (PEEK) material considering four different shapes namely: square, circle, rectangle and elliptical, for the central window to occupy bone graft. The major design constrain for a successful cage is minimized cage stress, in order to avoid subsidence. Finite Element (FE) analysis results revealed that the cage stress values obtained during the physiological motion varied depending upon the shape of the central window provided for bone graft. The objective of this study is to optimize the central window shape using the Teaching Learning Based Optimization (TLBO) algorithm. It was found that square and elliptical shape bone graft cavity resulted in better outcomes. Additional experimental study was also conducted with a six-axis spine simulator. Based on the optimization results, we manufactured two PEEK cage models with square and elliptical shaped central window using additive manufacturing. A prototype model of the C4-C5 level made of Polyvinylchloride (PVC) was used for experiment due to the existing constraints for using a cadaveric model. The experimental results were cross-verified using FE analysis. Thus, we would like to conclude that square and elliptical shape of the central window were the better design factor for our novel dynamic cage.

Unexpected Bone Formation after Stand-Alone Anterior Cervical Discectomy and Fusion Using Polyetheretherketone Cage with i-Factor

Several recent studies have revealed that anterior cervical discectomy and fusion (ACDF) with i-factor, a bone substitute material, is safe and effective, with a superior fusion rate. Clinical studies with i-factor have thus far been shown favorable results, despite theoretical concerns; moreover, no adverse events related to i-factor after ACDF have been reported. Herein, we discuss two cases that presented unexpected bone formation after ACDF using polyetheretherketone (PEEK) cage with i-factor. A 60-year-old male patient underwent stand-alone ACDF surgery at the C4–5–6–7 level. The appropriate PEEK cage was selected, filled with an i-factor 2.5 mL divided into 1/3 that was intermixed with autologous bone chips, The patient developed mild dysphagia 1 month after surgery. A simple cervical spine radiograph showed unexpected bone formation in the anterior portion of the vertebral body at C6 and C7 levels. A 67-year-old male patient underwent stand-alone ACDF surgery at the C3–4 level. The appropriate PEEK cage was selected, filled with 1 mL of i-factor 1 mL that was intermixed with autologous bone chips. The patient developed mild dysphagia 3 months after surgery. Computed tomography (CT) scan revealed the presence of a bridging bone at the graft level, but showed unexpected bone formation in the anterior portion of the vertebral body. The unexpected bone formation causing dysphagia that we observed may be due to the high potent bone-inductive capacity of i-factor, but instead because there are no guidelines on proper dosage and usage. Further biomechanical studies are required to determine the optimal dose and usage instruction of i-factor.