Clinical experience using polyetheretherketone (PEEK) intervertebral structural cage for anterior cervical corpectomy and fusion

Comparison of Three Grafting Options for Anterior Cervical Corpectomy and Fusion: A Retrospective 3-Arms Case Control Study

BACKGROUND

Anterior cervical corpectomy and fusion achieves foraminal radicular and central medullary decompression and spinal stabilization in staged lesions. Many bone graft materials have been developed for the reconstruction of cervical lordosis and the restoration of intervertebral height after corpectomy. The PolyEtherKetoneEtherKetoneKetone (PEKEKK) is a semicrystalline thermoplastic polymer that can be reinforced with carbon fibers to create long and highly fenestrated rectangular cervical cages for corpectomy. This study aimed to evaluate the radiological outcomes of an innovative PEKEEKK cage compared with others grafting options.

METHODS

Forty-five consecutive patients who underwent surgery with PEKEKK cages between 2017 and 2019 at a spine institution, were matched with 15 patients with a titanium mesh cylindrical cage (TMC) and 15 patients with a tricortical structural iliac bone graft. The restoration of vertebral height and cervical lordosis postoperatively, and subsidence of the construct were evaluated. Complications were reported.

RESULTS

The minimal follow-up was 5.1±2years. A better, but nonsignificant, postoperative gain in height was observed for PEKEKK (+8.1 ± 20%) and TMC cages (+8.2 ± 16%) than for iliac crest autograft reconstruction (+2.3 ± 15%, P = 0.119). The mean subsidence at the last follow-up was greater for TMC cages (-10.2 ± 13%), but was not significant, with -6.1 ± 10% for PEKEKK cages and -4.1 ± 7% for iliac crest autografts (P = 0.223). The gain in segmental cervical lordosis was significant (P < 0.001) and remained stable in all the groups.

CONCLUSIONS

Although an improvement in radiologic anatomical parameters can be achieved with all cage groups, the PEKEKK cage can be considered as a safe alternative for reducing subsidence.

Tumor Shape-Specific Brachytherapy Implants by 3D-Printing, Precision Radioactivity Painting, and Biomedical Imaging

In brachytherapy (BT), or internal radiation therapy, cancer is treated by radioactive implants. For instance, episcleral plaques (EPs) for the treatment of uveal melanoma, are designed according to generic population approximations. However, more personalized implants can enhance treatment precision through better adjustment of dose profiles to the contours of cancerous tissues. An original approach integrating biomedical imaging, 3D printing, radioactivity painting, and biomedical imaging, is developed as a workflow for the development of tumor shape-specific BT implants. First, computer-aided design plans of EP are prepared according to guidelines prescribed by the Collaborative Ocular Melanoma Study protocol. Polyetheretherketone (PEEK), a high-performance polymer suitable for permanent implants, is used to 3D-print plaques and the geometrical accuracy of the printed design is evaluated by imaging. The possibility to modulate the dose distribution in a tridimensional manner is demonstrated by painting the inner surfaces of the EPs with radioactive 103Pd, followed by dose profile measurements. The possibility to modulate dose distributions generated by these 3D-printed plaques through radioactivity painting is therefore confirmed. Ex vivo surgical tests on human eyeballs are performed as an assessment of manipulation ease. Overall, this work provides a solution for the fabrication of tumor-specific radioactive implants requiring higher dose precision.

Evaluation of the Grafting Efficacy of Active Biomolecules of Phosphatidylcholine and Type I Collagen on Polyether Ether Ketone: In Vitro and In Vivo

Biomolecule grafting on polyether ether ketone (PEEK) was used to improve cell affinity caused by surface inertness. This study demonstrated the sequence-polished (P) and sulfonated (SA) PEEK modification to make a 3D structure, active biomolecule graftings through PEEK silylation (SA/SI) and then processed with phosphatidylcholine (with silylation of SA/SI/PC; without SA/PC) and type I collagen (COL I, with silylation of SA/SI/C; without SA/C). Different modified PEEKs were implanted for 4, 8, and 12 weeks for histology. Sulfonated PEEK of SA showed the surface roughness was significantly increased; after the silylation of SA/SI, the hydrophilic nature was remarkably improved. The biomolecules were effectively grafted through silylation, and the cells showed improved attachment after 1 h. Furthermore, the SA/SI/PC group showed good in vitro mineralization. The new bone tissues were integrated into the 3D porous structures of SA/SI/PC and SA/SI/C in vivo making PEEK a potential alternative to metals in orthopedic implants.

ACDF plus Uncovertebrectomy versus ACDF alone for the Treatment of Cervical Spondylotic Radiculopathy: Minimum 5-Year Follow-Up

OBJECTIVE

 The surgical approach for cervical spondylotic radiculopathy (CSR) is controversial. This study aims to investigate the effectiveness of the combined anterior cervical diskectomy and fusion (ACDF) and uncovertebrectomy for treatment of CSR.

METHODS

 This is a retrospective case control study. One hundred and forty-six patients with CSR who underwent two different procedures (ACDF alone [group A]) and a combination of ACDF and uncovertebrectomy [group B]) from March 2008 to April 2013 were included. The operation time, blood loss, Visual Analog Scale scores of the neck (VAS-neck) and arm (VAS-arm), Neck Disability Index (NDI) score, 36-Item Short Form Health Survey (SF-36) score, fusion segment curvature, global cervical curvature, and the rate of surgical complication were evaluated.

RESULTS

 There were no significant differences in the basic demographic and clinical characteristics between the two groups (p > 0.05). No significant differences were noticed in the fusion segment curvature and global cervical curvature between the two groups (p > 0.05). Whereas the operation time and blood loss in group B were greater than those in group A (p < 0.05), the VAS-neck, VAS-arm, NDI, and SF-36 scores were better in group B (p < 0.05). The surgical complication rate between the two groups was not significantly different (p > 0.05).

CONCLUSIONS

 Clinical efficacy of ACDF plus uncovertebrectomy for the treatment of patients with CSR may be better than that of ACDF alone, but at the expense of more operation time and blood loss.

Evaluation of callus formation in distal femur fractures after carbon fiber composite versus stainless steel plate fixation

INTRODUCTION

Carbon-fiber-reinforced polyetheretherketone (CFR) composite plates have a more favorable stress modulus than stainless steel (SS) plates that may confer an advantage to bridge plating. The purpose of this study was to compare callus formation after CFR and SS plating of distal femur fractures.

METHODS

A retrospective review identified distal femoral fractures treated with CFR (n = 10) and SS (n = 21) plate fixation. Callus formation was measured using the modified Radiographic Union Score for Tibia (mRUST) at 3- and 6-month follow-up by three orthopedic trauma surgeons. Loss of alignment, implant failure, and revision surgeries were reviewed.

RESULTS

At 3 months, the mRUST in the CFR and SS groups was 9.0 (range, 6.3-12.3) and 6.9 (range, 4.3-11.7), respectively (p = 0.01). At 6 months, the mRUST in the CFR and SS groups was 11.4 (range, 7.7-16.0) and 10.5 (range, 6.0-15.7), respectively (p = 0.3). CFR and SS groups had a loss of fracture alignment in 1 (10%) and 1 (5%) patient, respectively (p = 0.5), and an unplanned revision surgery in 0 (0%) and 3 (15%) patients, respectively (p = 0.2). All three revisions surgeries in the SS group were for nonunion repair.

CONCLUSIONS

Treatment of distal femur fractures with CFR versus SS plating resulted in greater callus formation at 3 months. At 6 months, there was no difference in callus formation between groups. A larger series of patients is necessary to determine if the observed early increased callus formation confers a benefit to clinical outcomes.

LEVEL OF EVIDENCE

Therapeutic level III.

The use of Carbon-Peek volar plate after distal radius osteotomy for Kienbock's Disease in a volleyball athlete: a case report

Kienbock’s Disease, or lunatomalacia, has uncertain etiopathogenesis, it is more common in male from 20 to 45-year-old. The Lichtman’s classification is the most used by authors and it divides Kienbock’s Disease in 4 stages according to radiographic parameters. In early stages could be performed a conservative treatment, but failure rate is high; various surgical techniques are available in case of failure or higher stages. We report a case of a 26-year-old female volleyball player affected by stage I Kienbock’s Disease who underwent distal radius osteotomy core decompression synthesized with Carbon-Peek plate fixation. Follow-up was performed with clinical evaluation (ROM analysis, VAS score, Quick Dash Score), wrist radiographs and wrist MRI. (www.actabiomedica.it)

Clinical and radiological results comparison of allograft and polyetheretherketone cage for one to two-level anterior cervical discectomy and fusion: A CONSORT-compliant article

BACKGROUND

Recently, many kinds of cages for cervical fusion have been developed to avoid the related complications caused by tricortical iliac crest graft. The existing literature has reported the excellent clinical efficacy and superior fusion rate. However, various types of cages have their own disadvantages. Which bone graft material is the best choice for cage with the fewest complications? At present, there is still no conclusion.

METHODS

By reviewing patients with 1 to 2-level cervical degenerative disease in our hospital with a novel cage made of allograft or polyetheretherketone (PEEK), we evaluated the efficacy and reliability of the new cage in anterior cervical discectomy and fusion (ACDF). From 2015 to 2016, a prospective review of 58 and 49 consecutive cases with spondylotic radiculopathy or myelopathy undergoing ACDF using allograft (group A) and PEEK (group B) cage were performed. The follow-up ranged from 12 to 40 months. Intraoperative index, clinical outcome and complications were recorded. Radiographs evaluated segmental and overall cervical lordosis, the height of the intervertebral space, interbody height ratio (IHR), cage positioning, and fusion state.

RESULTS

A total of 134 cages were implanted. Compared to preoperatively, the visual analog scale (VAS) and neck disability index (NDI) were reduced postoperatively without any change during the subsequent follow-up in both groups. There was no migration or extrusion of the cages at the latest follow-up. There were 2 and 4 patients suffering dysphagia respectively. In both groups, the intervertebral height, IHR, segmental and overall cervical lordosis were significantly greater than pre-operation (P < .05) and were maintained at the last follow-up, but were not statistically significant (P > .05). The allograft group achieved a fusion rate of 100% (58/58) according to CT scans at 3 months post-operation, while PEEK group was 91.8% (45/49), which reached 95.9% (47/49) at 6 months and 100% at 12 months. In addition, the fusion state was maintained in all patients at the last follow-up.

CONCLUSION

Our data showed that the new allograft cage is superior to the PEEK cage in providing a high fusion rate and fewer complications after 1-level and 2-level ACDF procedures. It may represent an excellent alternative to other cages.

Correlation Between Different Interbody Grafts and Pseudarthrosis After Anterior Cervical Discectomy and Fusion Compared with Control Group: Systematic Review

BACKGROUND

Cervical spine degenerative disease is one of the main causes of myelopathy. Anterior cervical discectomy and fusion (ACDF) is the most common surgical procedure used to treat cervical myelopathy. Therefore, it is important to study pseudarthrosis rates after ACDF and correlate them with the graft used.

METHODS

We performed a systematic review to evaluate the relationship between pseudarthrosis after ACDF and the interbody graft used.

RESULTS

A total of 3732 patients were evaluated in 46 studies. The mean age of the included patients was 51.5 ± 4.18 years (range, 42-59.6 years). ACDF is most often perforemd as single-level surgery and the level most impaired is C5-C6. The use of titanium cages, zero profile, recombinant human bone morphogenetic protein 2, and carbon cages was seen as a protective factor for pseudarthrosis compared with the autograft group (control group); with an odds ratio of 0.29, 0.51, 0.03, and 0.3, respectively; the results were statistically relevant. The use of polyetheretherketone, poly(methyl methacrylate), and trabecular metal was a risk factor for development of pseudarthrosis compared with the control group, with an odds ratio of 1.7, 8.7, and 6.8, respectively; the results were statistically relevant. Radiologic follow-up was an important factor for the pseudarthrosis rate; paradoxically, a short follow-up (<1 year) had lower rates of pseudarthrosis and follow-up >2 years increased the chance of finding pseudarthrosis.

CONCLUSIONS

Different types of grafts lead to a significant difference in pseudarthrosis rates. Follow-up time is also an important factor that affects the rate of pseudarthrosis after ACDF.

Anterior cervical discectomy and fusion: review and update for radiologists

OBJECTIVES

The goals of this article are to describe the various types of interbody grafts and anterior cervical plating systems, techniques for optimizing evaluation of cervical spine metallic implants on CT and MR imaging, expected appearance and complications of ACDF on postoperative imaging and imaging assessment of fusion. Optimization for optimizing metal induced artifacts.

CONCLUSION

Currently, ACDF is the most commonly performed surgical procedure for degenerative cervical spine disease. Interbody fusion is performed with bone grafts or interbody spacers, and may be supplemented with anterior cervical plating. Compressive pathologies at the vertebral body level may be addressed by simultaneous corpectomy. Postoperatively, imaging plays an integral role in routine screening of asymptomatic individuals, fusion assessment and evaluation of complications.

PEEK radiolucent plate for distal radius fractures: multicentre clinical results at 12 months follow up

INTRODUCTION

Open reduction and internal fixation (ORIF) with plate and screws represents the recommended treatment for unstable intra-articular distal radius fractures. Although significant progresses in surgical technique have been made, anatomical reconstruction of radio-carpal articular surface still represent a difficult task, especially in multifragmentary fractures. Available PEEK reinforced-carbon fiber composite radiolucent devices allow both an easier and more careful assessment of intra-operative reduction of the articular surface of distal radius and prompt correction of any residual step deformity.

MATERIALS AND METHODS

We retrospectively reviewed clinical and radiological multicentre results of 71 consecutive AO B and C fracture pattern of distal radius treated using the same PEEK reinforced-carbon fiber composite radiolucent plate.

RESULTS

Three patients lost at final follow up and 4 cases with incomplete radiological documentations were excluded from the study. 64 patients (38 females, 26 males) were available and formed the basis of this report. Fracture types included 9 patients with 23-B, 13 patients 23-B2,15 patients with 23-B3,10 patients with 23-C1, 7 patients with 23-C2 and 10 patients with 23-C3. Mean Modified Mayo wrist Score was on average 38.11 (SD 10.1; range 24-75, 95%CI 34.7-41.4), 67.22 (SD 9.6, range 50-90, 95%CI 64-70.4), 90.54 (SD 6.3, range 75-100, 95%CI 88.4-92.6) at one, two and twelve months of follow-up, respectively. A statistically significant difference was found between mean scores at different follow-up periods (p = 0.001). We noted 1 case of distal screw fixation aseptic loosening at 5 months post surgical intervention.

CONCLUSIONS

PEEK reinforced-carbon fiber composite radiolucent plate represents a useful device for treatment of complex distal radius fractures in the adult population. It possesses unique biomechanical properties and allows for an easier anatomical reduction during surgical intervention.

[PEEK cage fusion after anterior cervical corpectomy : Clinical and radiological results in patients with spondylotic myelopathy]

BACKGROUND

Anterior cervical corpectomy and fusion (ACCF) has become a standard procedure for patients with spondylotic myelopathy due to multisegmental stenosis of the cervical canal. In addition to the fusion technique using autogenous bone grafts and titanium implants, synthetic polyetheretherketone (PEEK) cages have been used increasingly during the last years. However, limited evidence on the clinical and radiological results of PEEK cages for ACCF exists in the literature. The study presented here is the largest series to date reporting clinical and radiological outcome as well as complication rates after one to three-level ACCF using PEEK cages augmented by an anterior plate-screw osteosynthesis.

MATERIALS AND METHODS

Retrospective study on 101 patients after stand-alone PEEK cage-ACCF with a minimum follow-up of 6 months. The number of hardware failures and implant-related surgical revisions were determined. The rate of subsidence and fusion and the course of lordotic alignment were analysed. The neck disability index (NDI) and the European myelopathy score (EMS) were assessed.

RESULTS

Screw complications were detected in 8/101 cases and 3 cases of cage dislocation occurred, resulting in an overall implant related revision rate of 2.9 % (all revision cases showed cage dislocation). The rate of cage subsidence >3 mm was 12 % and solid fusion was achieved in 82 % of the patients. NDI, EMS and lordotic alignment improved significantly.

CONCLUSIONS

PEEK cages are a safe and effective alternative to titanium cages or autogenous bone graft for ACCF. Further randomized evaluation of different fusion techniques in ACCF is still necessary.

Cervical corpectomies: results of a survey and review of the literature on diagnosis, indications, and surgical technique

OBJECTIVES

Cervical corpectomy is an uncommon procedure and there are only limited data on the procedure's indications, surgical approaches, and complications. The diagnosis, indications, surgical planning, and complications of cervical corpectomy were therefore surveyed to clarify the treatment strategies used by spinal surgeons in central Europe, with special attention to preoperative planning and decision-making for additional dorsal approaches in multilevel cases.

MATERIALS AND METHODS

An online survey with 18 questions on the preoperative, intraoperative, and postoperative management of cervical corpectomies was conducted. The relevant specialist societies in Germany and Austria provided 1137 contacts for surgeons, and the responses were compared with recent literature reports.

RESULTS

In all, 302 surgeons (27 %) completed the survey, with wide variability in the treatment options offered. Most (51 %) perform fewer than five anterior cervical corpectomy and fusion (ACCF) procedures per year; 35 % do 5-20 per year. Anterior cervical discectomy and fusion (ACDF) was preferred by 41 % of the participants to laminoplasty/laminectomy (19 %/16 %) and ACCF (12 %). Most indications for ACCF involved degenerative (27 %), traumatic (17 %), and neoplastic (20 %) conditions. Intraoperative and postoperative complications were mainly associated with hardware failure. One-third of the surgeons tend to use an additional dorsal approach to increase the corpectomy construct's stability for either two-level or three-level corpectomies.

CONCLUSIONS

There is no current consensus in central Europe on the treatment of complex cervical disease and cervical corpectomy. The procedure is still rare, and the need for additional dorsal fixation is unclear. Further studies are needed in order to establish evidence-based standards for patient care.

Polyetheretherketone (PEEK) for medical applications

Polyetheretherketone (PEEK) is a polyaromatic semi-crystalline thermoplastic polymer with mechanical properties favorable for bio-medical applications. Polyetheretherketone forms: PEEK-LT1, PEEK-LT2, and PEEK-LT3 have already been applied in different surgical fields: spine surgery, orthopedic surgery, maxillo-facial surgery etc. Synthesis of PEEK composites broadens the physicochemical and mechanical properties of PEEK materials. To improve their osteoinductive and antimicrobial capabilities, different types of functionalization of PEEK surfaces and changes in PEEK structure were proposed. PEEK based materials are becoming an important group of biomaterials used for bone and cartilage replacement as well as in a large number of diverse medical fields. The current paper describes the structural changes and the surface functionalization of PEEK materials and their most common biomedical applications. The possibility to use these materials in 3D printing process could increase the scientific interest and their future development as well.

Long-term results of anterior cervical corpectomy and fusion with nano-hydroxyapatite/polyamide 66 strut for cervical spondylotic myelopathy

To assess the long-term clinical and radiographic outcomes of anterior cervical corpectomy and fusion (ACCF) with a neotype nano-hydroxyapatite/polyamide 66 (n-HA/PA66) strut in the treatment of cervical spondylotic myelopathy (CSM). Fifty patients with CSM who underwent 1- or 2-level ACCF with n-HA/PA66 struts were retrospectively investigated. With a mean follow-up of 79.6 months, the overall mean JOA score, VAS and cervical alignment were improved significantly. At last follow-up, the fusion rate was 98%, and the subsidence rate of the n-HA/PA66 strut was 8%. The "radiolucent gap" at the interface between the n-HA/PA66 strut and the vertebra was further noted to evaluate the osteoconductivity and osseointegration of the strut, and the incidence of it was 62% at the last follow-up. Three patients suffered symptomatic adjacent segment degeneration (ASD). No significant difference was detected in the outcomes between 1- and 2-level corpectomy at follow-ups. In conclusion, the satisfactory outcomes in this study indicated that the n-HA/PA66 strut was an effective graft for cervical reconstruction. Moreover, the osteoconductivity and osseointegration of the strut is still need to be optimized for future clinical application owing to the notably presence of "radiolucent gap" in present study.

Effects of Different pH-Values on the Nanomechanical Surface Properties of PEEK and CFR-PEEK Compared to Dental Resin-Based Materials

The study determines the stability and durability of polyetheretherketone (PEEK) and a carbon fiber-reinforced PEEK (CFR-PEEK) with 30% short carbon fibers, a dental composite based on Bis-GMA and polymethylmethacrylate (PMMA) under the influence of different pH-values of the oral environment in vitro. Nanomechanical properties were investigated by nanoindentation and nanoscratch tests before and after incubation of the specimens at 37 °C for 30 days in artificial saliva with pH-values of 3, 7 and 10, respectively. Nanoindentation and nanoscratching tests were performed using the Hysitron TI950 TriboIndenter to evaluate the reduced elastic moduli, nanohardness, viscoelasticity, friction coefficient and residual scratch profiles. After treatment, the nanomechanical properties of unfilled PEEK did not change. The reduced elastic moduli and nanohardness of the carbon fiber-reinforced PEEK increased significantly. The reduced elastic moduli and nanohardness of CHARISMA decreased. The plasticity of all materials except that of the unfilled PEEK increased. This indicates that different pH-values of the artificial saliva solutions had no obvious influences on the nanomechanical properties of the PEEK matrix. Therefore, the aging resistance of the unfilled PEEK was higher than those of other materials. It can be deduced that the PEEK matrix without filler was more stable than with filler in the nanoscale.

A new volar plate made of carbon-fiber-reinforced polyetheretherketon for distal radius fracture: analysis of 40 cases

BACKGROUND

Implants based on the polyetheretherketon (PEEK) polymer have been developed in the last decade as an alternative to conventional metallic devices. PEEK devices may provide several advantages over the use of conventional orthopedic materials, including the lack of metal allergies, radiolucency, low artifacts on magnetic resonance imaging scans and the possibility of tailoring mechanical properties. The purpose of this study was to evaluate the clinical results at 12-month follow-up using a new plate made of carbon-fiber-reinforced polyetheretherketon for the treatment of distal radius fractures.

MATERIALS AND METHODS

We included 40 consecutive fractures of AO types B and C that remained displaced after an initial attempt at reduction. The fractures were classified according to the AO classification: 21 fractures were type C1, 9 were type C2, 2 were type C3, 2 were type B1 and 6 were type B2.

RESULTS

At a 12-month follow-up no cases of hardware breakage or loss of the surgically achieved fracture reduction were documented. All fractures healed, and radiographic union was observed at an average of 6 weeks. The final Disabilities of Arm, Shoulder and Hand score was 6.0 points. The average grip strength, expressed as a percentage of the contralateral limb, was 92 %. Hardware removal was performed only in one case, for the occurrence of extensor tenosynovitis.

CONCLUSION

At early follow-up this device showed good clinical results and allowed maintenance of reduction in complex, AO fractures.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

Risk factors for subsidence in anterior cervical fusion with stand-alone polyetheretherketone (PEEK) cages: a review of 82 cases and 182 levels

INTRODUCTION

To determine risk factors for subsidence in patients treated with anterior cervical discectomy and fusion (ACDF) and stand-alone polyetheretherketone (PEEK) cages.

MATERIALS AND METHODS

Records of patients with degenerative spondylosis or traumatic disc herniation resulting in radiculopathy or myelopathy between C2 and C7 who underwent ACDF with stand-alone PEEK cages were retrospectively reviewed. Cages were filled with autogenous cancellous bone harvested from iliac crest or hydroxyapatite. Subsidence was defined as a decrease of 3 mm or more of anterior or posterior disc height from that measured on the postoperative radiograph. Eighty-two patients (32 males, 50 females; 182 treatment levels) were included in the analysis.

RESULTS

Most patients had 1-2 treatment levels (62.2 %), and 37.8 % had 3-4 treatment levels. Treatment levels were from C2-7. Of the 82 patients, cage subsidence occurred in 31 patients, and at 39 treatment levels. Multivariable analysis showed that subsidence was more likely to occur in patients with more than two treatment levels, and more likely to occur at treatment levels C5-7 than at levels C2-5. Subsidence was not associated with postoperative alignment change but associated with more disc height change (relatively oversized cage).

CONCLUSION

Subsidence is associated with a greater number of treatment levels, treatment at C5-7 and relatively oversized cage use.