|Year : 2020 | Volume
| Issue : 2 | Page : 118-123
Stand-alone polyetheretherketone cages for anterior cervical discectomy and fusion for successive four-level degenerative disc disease without plate fixation
Ahmed M Ashour1, Ibrahim Abdelmohsen1, Medhat El Sawy2, Ahmed Faisal Toubar1
1 Department of Neurosurgery, Ain Shams University, Cairo, Egypt
2 Department of Neurosurgery, El-Menia University, Menia, Egypt
|Date of Submission||06-May-2020|
|Date of Acceptance||07-May-2020|
|Date of Web Publication||5-Jun-2020|
Dr. Ahmed M Ashour
Department of Neurosurgery, Ain Shams University, Abbasia Square, Cairo 11391
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Background: Anterior cervical discectomy with fusion became the most frequently performed technique for the treatment of symptoms related to cervical disc prolapse. Multilevel anterior cervical discectomy has been combined with anterior cervical plate application to help maintain the cervical lordosis and enhance fusion. This was associated with more soft-tissue separation and retraction with increased incidence of surgically related complications and postoperative dysphagia.Aim of the Study: The aim of this study is to evaluate the safety and efficacy of the stand-alone cervical polyetheretherketone (PEEK) cages in four-level discectomy and to determine if it is possible to avoid anterior plate fixation and to achieve satisfactory outcomes.
Methodology: This is a retrospective study which was performed between June 2011 and December 2018 at one institute. The clinical and radiological data were collected from patients who underwent successive four-level anterior cervical discectomy and fusion with PEEK cages for degenerative cervical disc disease without plate fixation.
Results: This study included 66 patients, 35 males and 31 females. The follow-up period was 24 months. Mean Japanese Orthopedic Association scores were 13.3 ± 1.41 preoperative and 15.9 ± 0.86 postoperative (P = 0.046). The cervical curvature index “Ishihara” (ICI) was 9.9 ± 5.90 preoperative and the mean of ICI was 10.5 ± 6.65 postoperative, which is insignificant, P = 0.7). The lordotic curvature according to these results was preserved till the end of the year and half of the follow-up period postoperative.
Conclusion: Consecutive four-level anterior discectomy with PEEK cage interbody fusion without plate and screw is a safe and effective procedure in the absence of instability, and it may be a reliable alternative for the treatment of multilevel cervical disc.
Keywords: Anterior cervical discectomy, cervical disc, cervical plate, four-level cervical disc
|How to cite this article:|
Ashour AM, Abdelmohsen I, Sawy ME, Toubar AF. Stand-alone polyetheretherketone cages for anterior cervical discectomy and fusion for successive four-level degenerative disc disease without plate fixation. J Craniovert Jun Spine 2020;11:118-23
|How to cite this URL:|
Ashour AM, Abdelmohsen I, Sawy ME, Toubar AF. Stand-alone polyetheretherketone cages for anterior cervical discectomy and fusion for successive four-level degenerative disc disease without plate fixation. J Craniovert Jun Spine [serial online] 2020 [cited 2020 Sep 22];11:118-23. Available from: http://www.jcvjs.com/text.asp?2020/11/2/118/285945
| Introduction|| |
Anterior cervical discectomy and fusion (ACDF) is a widely performed surgical procedure for radiculopathy and myelopathy that result from degenerative cervical disc disease., Since the initial procedure by Smith and Robinson, anterior cervical arthrodesis procedure has been tuned for the treatment of degenerative cervical disc disease. However, the failure rates increase as the levels of discectomies increase. Multilevel cervical discectomies are usually combined with plate fixation to keep the spinal curvature and increasing the rate of fusion.,,, The insertion of a plate over multiple vertebral bodies requires more tissue retraction which may increase the risk of occurrence of complications, such as screw breakage, pull out, esophageal injury, and recurrent laryngeal nerve injury. Such complications can compromise the satisfactory final outcome decompression of the spinal cord and/or nerve roots and bone fusion with maintenance of cervical lordotic curvature.,,,,
Synthetic cages from polyetheretherketone (PEEK) cages have been designed to restore and keep stability immediately and to promote bone growth inside and around the cage.,,,, Clinical results of using interbody cages without plate fixation for single or two level (s) are encouraging. To our knowledge, ACDF without plate fixation showed a satisfactory fusion rate and neurological outcome after three levels of cervical discectomies,, which has lowered the complications and decreased the length of stay, pushing the interbody cage fusion without plate to be superior to fusion with plate., However, in long multilevel cervical reconstruction with cages, subsidence may occur. The aim of this study is to evaluate the safety and efficacy of the stand-alone cervical PEEK cages in four-level discectomy and to determine if it is possible to avoid anterior plate fixation and to achieve satisfactory outcomes.,,,
| Methodology|| |
A retrospective study was performed between June 2011 and December 2018 at one institute. The clinical and radiological data were collected in patients who underwent successive four-level ACDF with PEEK cages for degenerative cervical disease without plate fixation system. Inclusion criteria were patients suffering from radiculopathy, myelopathy, or a combination of both due to nerve root or cord compression with four-level successive degenerative disc disease, including ossified posterior longitudinal ligament and disc osteophyte complex, while exclusion criteria were patients with previous cervical surgery and cervical instability from the study cohort. Sixty-six patients were enrolled in the study, and radiological and clinical follow-up period was 2 years.
In supine position, intraoperative fluoroscopy was used to confirm the adequate exposure of the required levels, before a transverse incision at the midway level of the required levels or a longitudinal skin incision, medial to right sternocleidomastoid muscle to access the prevertebral space [Figure 1]. Standard macroscopic and microscopic discectomy was done in all patients. The osteophytes were excised with a Kerrison, and both end plates were decorticated. The posterior longitudinal ligament was removed to confirm sufficient decompression. The PEEK cages were packed with artificial bone granules (calcium hydroxyapatite in low crystalline form) and then inserted into the disc space. The cage is formed of PEEK with two serrated retention teeth to prevent migration and markers made of titanium alloy which indicates cage position on X-ray. The implants were available in four heights of 4, 5, 6, and 7 mm with an internal anteroposterior width of 12 or 14 mm. After cages insertion, intraoperative fluoroscopic was used to confirm the proper location of the cages, and submuscular drain was inserted in all cases. All patients postoperative were kept in a Philadelphia neck collar for 6 weeks.
|Figure 1:Intraoperative exposure after longitudinal incision and four-cage insertion|
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Outcome and follow-up
Postoperative, clinical, and radiological follow-up was done at the 3rd, 6th, 12th, and 24th months. Standard neurological evaluation and the modified Japanese Orthopedic Association (JOA) scoring system were used to assess the clinical outcome. Spinal curves, mobility, and fusion status with X-ray were recorded and evaluated. Anteroposterior, lateral, and flexion/extension images were obtained immediately after surgery and at follow-up intervals after surgery.
The cervical levels were defined to be successfully fused if there was no change in mobility of the fused levels on flexion and extension views obtained at 12–24 months postoperative without pain and with intact hardware. Fusion was assessed by existence of trabecular continuity, bone mass bridging across the disc space, and a cloudy interface between the cage and the end plates. Furthermore, images were assessed according to the classification of Vavruch et al. of the anterior cervical fusion; Type 1A is defined as bridging bone anterior and through the disc space, while 1B as bridging bone anterior but not through the disc space, 2A as bridging bone not anterior but through the disc space, and 2B as no bridging bone at all “pseudarthrosis.” Fusion group included 1A, 1B, or 2A while the Non-fusion group included 2B. Ishihara Curvature Index (ICI) of the lateral view was used to the degree of spinal curvature; which is the value calculated by adding the distance between 4 lines connecting the posteroinferior border of C2 to the posteroinferior border of C7 and each of the posteroinferior borders of the C3 to C6 “a3-a6”, and then divided by the distance of a line extended from the posteroinferior border of the C2 to C7 “CD” (spinal curvature index: [a3+a4+a5+a6]/CD×100). A positive intersection length indicated the degree of lordosis. If negative, it indicates kyphosis, while zero, defined as straight. A 3-mm reduction or more in the interbody height was defined as subsidence in the interbody height on the immediate postoperative and 12th-month follow-up images.
Statistical analyses were done with the IBM SPSS 22 software program (IBM, Armonk, New York, USA). Data are presented as mean ± standard deviation. P < 0.05 was considered statistically significant.
| Results|| |
There were 35 men and 31 women between the ages ranging from 36 to 68 years, with a mean age of 48. All patients were followed up for at least 24 months [Table 1]. Patients with C3 till C7 discectomies were 59 (89.1%) [Figure 2] and C2 till C6 were 7 (10.9%) [Figure 3]. Postoperative, no neurological deterioration occurred except in two cases who developed transient C5 root palsy and resolved within a month and in other case deterioration of motor power from G4 to G3 according to the Medical Research Council scale which resolved within 6 weeks. Postoperative X-rays confirmed the proper location of the PEEK cages [Figure 2]b. Mean JOA scores were 13.3 ± 1.41 preoperative and 15.9 ± 0.86 postoperative (P = 0.046). ICI of the lateral view used for curvature evaluation was 9.9 ± 5.90 preoperative, and the mean of ICI was 10.5 ± 6.65 postoperative. It was insignificant (P = 0.7). The lordotic curvature according to these results was preserved till the end of the year and half of follow-up period postoperative.
|Figure 2: Type 2A fusion case “2A as bridging bone not anterior but through the disc space,” (a) MRI of C3–C7 case, (b) intraoperative, (c) immediate postoperative, (d) 3-month follow-up, (e) 3-month follow-up CT scan, (f) 24-month follow-up|
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|Figure 3:Type 1A fusion case “1A is defined as bridging bone anterior and through the disc space,” (a) magnetic resonance imaging of C2–C6 case, (b) intraoperative, (c) immediate postoperative, (d) 3-month follow-up, (e) 12-month follow-up, (f) 20-month follow-up|
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At the final follow-up, the fusion rate of 1A, 1B, and 2A types was 92.4% (244/264 levels), while nonfusion type 2B “pseudarthrosis” 7.6% (20/264 levels) [Figure 3] and [Figure 4]. By the end of follow-up time no cage migration or collapse were observed [Figure 2] except in 3 cases (4.5%) belong to the nonfused group 2B in ten patients all were from C3–C7 group; they were all asymptomatic and kept on conservative management as no mobility was detected on flexion–extension images. Subsidence in the interbody height was seen in three cases (4.5%). All were in C3–C7 group seen in two consecutive levels in each case and were asymptomatic till 24 months of follow-up.
|Figure 4:Result distribution according to the level based on the classification of Vavruch et al. of the anterior cervical fusion; Type 1A is defined as bridging bone anterior and through the disc space, while 1B as bridging bone anterior but not through the disc space, 2A as bridging bone not anterior but through the disc space, and 2B as no bridging bone at all. Fusion group included 1A, 1B, or 2A while the Non-fusion group included 2B|
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| Discussion|| |
ACDF is a widely used procedure to treat multiple cervical spinal pathologies, as cervical spondylotic myelopathy, degenerative disc prolapse, and trauma. Regarding single-level ACDF, the studies concluded that it can achieve a variable fusion rate from 92% to 100% and a relief of neurological symptoms, which varied from 70% to 90%., In multilevel ACDF an autogenous bone graft usually fail to keep the spinal stability in multilevel discectomies properly and the complications rate related to the usage of autogenous bone graft increase when compared to single level discectomy, such as graft collapse 20%–30% seen in multilevel cases.,,,
Many literature had reported an increasing rate of nonfusion as the number of level discectomies increases 10%–12% for 1 level, 20%–25% for 2 levels, and about 30%–55% for 3 levels of fusions.,,, Hence, when a multilevel ACDF is being done, an augmentation with plate system for fixation seems to be preferred based on the fact that it may decrease the micromotion between consecutive levels and promote fusion rate and restoration of physiological sagittal lordosis. It has been reported that ACDF with plate fixation leads to better symptomatic pain relief and a higher fusion rate., However, the rate of pseudoarthrosis was 6%-–8% for one level and 25% for treatment of several levels in a retrospective study by Das et al. Furthermore, in three- and four-level ACDF, the fusion rates decreased to 35%, even when plates were used. The plate-associated morbidities varied from 2% to 20% as screw pullout, breakage, laryngeal nerve, esophageal injury, and root injuries. Longer operative time and hospital stay are reported as well.,, Such morbidity of the basic fusion techniques favored the cage technology. ACDF with cage was proved to be effective treatment of degenerative cervical disc pathologies, with high fusion rates ranging from 90% to 100%.,
Stand-alone cage concept was used by Bag for the 1st time, and then, it achieved an excellent outcome globally. Furthermore, the use of multiple cages for multilevel myelopathy and radiculopathy showed good outcome till 4 years of follow-up. In our study, the fusion rate was 92.4%, comparable to pervious similar studies in literature., The pseudarthrosis (fusion failure) in our study represented 7.6% (20/264 levels), while Chang et al. reported 0.04% of pseudarthrosis of 440 levels. However, these ten patients had no clinical symptoms observed during the 24-month follow-up period.
Subsidence was seen in three cases of C3–C7 group seen in two levels from the four levels and was asymptomatic. When anterior cervical plates are not used the subsidence is a common complication in multilevel, 9%–16.5% per level, while subsidence decrease during occurrence of fusion when plates are used due to its curve, In another study, the rate was 13/104 per level.,
No cage-related complications occurred, and the usage of the cages was found to keep the sagittal balance spinal (lordosis) and preserved the height of the cervical foramina as well. The insertion of cervical cage increases the foraminal height, which helps in nerve root decompression. Hwang et al. results match with our finding that PEEK cages alone for three or four levels without plate fixation had less postoperative morbidity. Furthermore, the wedge-shaped cage design restores the lordosis. In our study, we found that using multiple PEEK resulted in keeping and restoration of the preoperative lordotic curvature as calculated using ICI, which was 9.9 ± 5.90 preoperative and 10.5 ± 6.65 postoperative.
PEEK cages were used for multilevel ACDF as complication rates are less when compared to the other modalities. PEEK is a polymer, which provides a strength, stiffness, and resistance to compression as seen in biomechanical studies.,,, Furthermore, PEEK cage has more elastic properties than the other cages made from metals, decreasing the incidence of subsidence into the surrounding vertebrae. Regarding biocompatibility, PEEK cage has a stimulatory effect on osteoblasts, osteocalcin synthesis, and fibroblast proliferation. The cage design with titanium spikes on the upper and lower surfaces of the cage helps to anchor the cage offering somehow a similar function of plate and screws. The imaging criteria of PEEK being radiotransparent, which help in the evaluation of bone fusion and its artifacts, are negligible in magnetic resonance imaging and computed tomography scans.,,,,
The complications related to the usage of autologous tricortical iliac bone graft reduced markedly with the usage of PEEK cages. In most of the previous studies, PEEK cages were packed with cancellous bone; in our study, we used calcium hydroxyapatite in low crystalline form (bone granules) mixed with autologous blood.,,
To our knowledge, our clinical series of consecutive four-level ACDF without plating have not been reported in literature before with providence of such number of cases. Our results provides an evidence that usage of stand-alone cages without plate in ACDF procedures for consecutive four-level degenerative disc disease without the presence of instability is safe and effective. This is guided by intraoperative fluoroscopy for observation of the restoration of the lordotic curve and avoidance of excess removal of end plate to avoid subsidence.
| Conclusion|| |
Consecutive four-level anterior discectomy with PEEK cage interbody fusion without plate and screw is a safe and effective procedure in the absence of instability, and it may be a reliable alternative for the treatment of multilevel cervical disc. It keeps the spinal biodynamics and decreases the risk of complications related to screw and plate fixation systems.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
| References|| |
Mummaneni PV, Kaiser MG, Matz PG, Anderson PA, Groff MW, Heary RF, et al
. Cervical surgical techniques for the treatment of cervical spondylotic myelopathy. J Neurosurg Spine2009;11:130-41.
Wang JC, McDonough PW, Endow KK, Delamarter RB. Increased fusion rates with cervical plating for two-level anterior cervical discectomy and fusion. Spine (Phila Pa 1976) 2000;25:41-5.
Elias A, Kyriaki P, Polychronios S, Ioannis B, Athanasios S, Ioannis P. Stand-alone anterior cervical decompression and fusion in three levels with peek cages: A possible satisfactory alternative. J Neurol Neurosci 2017;08:237-240.
Song KS, Piyaskulkaew C, Chuntarapas T, Buchowski JM, Kim HJ, Park MS, et al
. Dynamic radiographic criteria for detecting pseudarthrosis following anterior cervical arthrodesis. J Bone Joint Surg Am 2014;96:557-63.
El-Tantawy A. Is it possible to eliminate the plate-related problems and still achieve satisfactory outcome after multilevel anterior cervical discectomy? Eur J Orthop Surg Traumatol 2015;25 Suppl 1:S135-45.
Panjabi MM, Cholewicki J, Nibu K, Grauer J, Babat LB, Dvorak J. Critical load of the human cervical spine: Anin vitro
experimental study. Clin Biomech (Bristol, Avon) 1998;13:11-7.
Smith GW, Robinson RA. The treatment of certain cervical-spine disorders by anterior removal of the intervertebral disc and interbody fusion. J Bone Joint Surg Am 1958;40-A: 607-24.
Kulkarni AG, Hee HT, Wong HK. Solis cage (PEEK) for anterior cervical fusion: Preliminary radiological results with emphasis on fusion and subsidence. Spine J 2007;7:205-9.
Song KJ, Taghavi CE, Hsu MS, Lee KB, Kim GH, Song JH. Plate augmentation in anterior cervical discectomy and fusion with cage for degenerative cervical spinal disorders. Eur Spine J 2010;19:1677-83.
Tye GW, Graham RS, Broaddus WC, Young HF. Graft subsidence after instrument-assisted anterior cervical fusion. J Neurosurg 2002;97:186-92.
Hilibrand AS, Yoo JU, Carlson GD, Bohlman HH. The success of anterior cervical arthrodesis adjacent to a previous fusion. Spine (Phila Pa 1976) 1997;22:1574-9.
Roguski M, Benzel EC, Curran JN, Magge SN, Bisson EF, Krishnaney AA, et al
. Postoperative cervical sagittal imbalance negatively affects outcomes after surgery for cervical spondylotic myelopathy. Spine (Phila Pa 1976) 2014;39:2070-7.
Lee CH, Kim KJ, Hyun SJ, Yeom JS, Jahng TA, Kim HJ. Subsidence as of 12 months after single-level anterior cervical inter-body fusion. Is it related to clinical outcomes? Acta Neurochir (Wien) 2015;157:1063-8.
Phillips FM, Carlson G, Emery SE, Bohlman HH. Anterior cervical pseudarthrosis. Spine (Phila Pa 1976) 1997;22:1585-9.
Suchomel P, Barsa P, Buchvald P, Svobodnik A, Vanickova E. Autologous versus allogenic bone grafts in instrumented anterior cervical discectomy and fusion: A prospective study with respect to bone union pattern. Eur Spine J 2004;13:510-5.
Samartzis D, Shen FH, Goldberg EJ, An HS. Is autograft the gold standard in achieving radiographic fusion in one-level anterior cervical discectomy and fusion with rigid anterior plate fixation? Spine (Phila Pa 1976) 2005;30:1756-61.
Sonntag VK. Point of view: Three-level anterior cervical discectomy and fusion. Spine (Phila Pa 1976) 1997;22:2625.
Demircan MN, Kutlay AM, Colak A, Kaya S, Tekin T, Kibici K, et al
. Multilevel cervical fusion without plates, screws or autogenous iliac crest bone graft. J Clin Neurosci 2007;14:723-8.
Kim WB, Hyun SJ, Choi H, Kim KJ, Jahng TA, Kim HJ. Long-term follow-Up results of anterior cervical inter-body fusion with stand-alone cages. J Korean Neurosurg Soc 2016;59:385-91.
Shriver MF, Lewis DJ, Kshettry VR, Rosenbaum BP, Benzel EC, Mroz TE. Pseudoarthrosis rates in anterior cervical discectomy and fusion: A meta-analysis. Spine J 2015;15:2016-27.
Echevarría A, Arroyave C. Electrochemical assessment of some titanium and stainless steel implant dental alloys. Rev Metal 2003;39:174-81.
Barsa P, Suchomel P. Factors affecting sagittal malalignment due to cage subsidence in standalone cage assisted anterior cervical fusion. Eur Spine J 2007;16:1395-400.
Epstein NE. Iliac crest autograft versus alternative constructs for anterior cervical spine surgery: Pros, cons, and costs. Surg Neurol Int 2012;3:S143-56.
] [Full text]
Chiang CJ, Kuo YJ, Chiang YF, Rau G, Tsuang YH. Anterior cervical fusion using a polyetheretherketone cage containing a bovine xenograftp: Three to five-year follow-up. Spine (Phila Pa 1976) 2008;33:2524-428.
Vavruch L, Hedlund R, Javid D, Leszniewski W, Shalabi A. Prospective randomized comparison between the cloward procedure and a carbon fiber cage in the cervical spine. Spine (Phila Pa 1976) 2002;27:1694-701.
Takeshita K, Murakami M, Kobayashi A, Nakamura C. Relationship between cervical curvature index (Ishihara) and cervical spine angle (C2--7). J Orthop Sci 2001;6:223-6.
Matgé G. Cervical cage fusion with 5 different implants: 250 cases. Acta Neurochir (Wien) 2002;144:539-49.
Matge G. Anterior interbody fusion with the BAK-cage in cervical spondylosis. Acta Neurochir (Wien) 1998;140:1-8.
Sharma A, Kishore H, Singh V, Shawky Abdelgawaad A, Sinha S, Kamble PC, et al
. Comparative study of functional outcome of anterior cervical decompression and interbody fusion with tricortical stand-alone iliac crest autograft versus stand-alone polyetheretherketone cage in cervical spondylotic myelopathy. Global Spine J 2018;8:860-5.
Kim YS, Park JY, Moon BJ, Kim SD, Lee JK. Is stand alone PEEK cage the gold standard in multilevel anterior cervical discectomy and fusion (ACDF)? Results of a minimum 1-year follow up. J Clin Neurosci 2018;47:341-6.
Ng EP, Yip AS, Wan KH, Tse MS, Wong KK, Kwok TK, et al
. Stand-alone cervical cages in 2-level anterior interbody fusion in cervical spondylotic myelopathy: Results from a minimum 2-year follow-up. Asian Spine J 2019;13:225-32.
Emery SE, Fisher RJ, Bohlman HH. Three-level anterior cervical discectomy and fusion. Spine (Phila Pa 1976) 1997;22:2622-4.
Fountas KN1, Kapsalaki EZ, Nikolakakos LG, Smisson HF, Johnston KW, Grigorian AA, et al
. Anterior cervical discectomy and fusion associated complications. Spine (Phila Pa 1976) 2007;32:2310-7.
Lee YS, Kim YB, Park SW. Risk factors for postoperative subsidence of single-level anterior cervical discectomy and fusion: The significance of the preoperative cervical alignment. Spine (Phila Pa 1976) 2014;39:1280-7.
Das K, Couldwell WT, Sava G, Taddonio RF. Use of cylindrical titanium mesh and locking plates in anterior cervical fusion. Technical note. J Neurosurg 2001;94:174-8.
Bishop RC, Moore KA, Hadley MN. Anterior cervical interbody fusion using autogeneic and allogeneic bone graft substrate: A prospective comparative analysis. J Neurosurg 1996;85:206-10.
Wang JC, McDonough PW, Endow KK, Delamarter RB. A comparison of fusion rates between single-level cervical corpectomy and two-level discectomy and fusion. J Spinal Disord 2001;14:222-5.
Wu WJ, Jiang LS, Liang Y, Dai LY. Cage subsidence does not, but cervical lordosis improvement does affect the long-term results of anterior cervical fusion with stand-alone cage for degenerative cervical disc disease: A retrospective study. Eur Spine J 2011;21:1374-82.
Castro FP Jr., Holt RT, Majd M, Whitecloud TS 3rd
. A cost analysis of two anterior cervical fusion procedures. J Spinal Disord 2000;13:511-4.
ElAbed K, Shawky A, Barakat M, Ainscow D. Anterior cervical discectomy and fusion with stand-alone trabecular metal cages as a surgical treatment for cervical radiculopathy: Mid-term outcomes. Asian Spine J 2016;10:245-50.
Barbagallo GM, Assietti R, Corbino L, Olindo G, Foti PV, Russo V, et al
. Early results and review of the literature of a novel hybrid surgical technique combining cervical arthrodesis and disc arthroplasty for treating multilevel degenerative disc disease: Opposite or complementary techniques? Eur Spine J 2009;18 Suppl 1:29-39.
Chang SW, Kakarla UK, Maughan PH, DeSanto J, Fox D, Theodore N, et al
. Four-level anterior cervical discectomy and fusion with plate fixation: Radiographic and clinical results. Neurosurgery 2010;66:637-9.
Zhou J, Li X, Dong J, Zhou X, Fang T, Lin H, et al
. Three-level anterior cervical discectomy and fusion with self-locking stand-alone polyetheretherketone cages. J Clin Neurosci 2011;18:1505-9.
Chung CK, Kim CH. Anterior plating is better than the stand-alone cage in the restoration of segmental kyphosis. Spine J 2012;12:S100.
Hwang SL, Lin CL, Lieu AS, Lee KS, Kuo TH, Hwang YF, et al
. Three-level and four-level anterior cervical discectomies and titanium cage-augmented fusion with and without plate fixation. J. Neurosurg Spine 2004;1:160-7.
Chen Y, Wang X, Lu X, Yang L, Yang H, Yuan W, et al
. Comparison of titanium and polyetheretherketone (PEEK) cages in the surgical treatment of multilevel cervical spondylotic myelopathy: A prospective, randomized, control study with over 7-year follow-up. Eur Spine J 2013;22:1539-46.
Williams DF, McNamara A, Turner RM. Potential of polyetheretherketone (PEEK) and carbon-fibre-reinforced PEEK in medical applications. J Mater Sci Lett 1987;6:188-90.
Cho DY, Liau WR, Lee WY, Liu JT, Chiu CL, Sheu PC. Preliminary experience using a polyetheretherketone (PEEK) cage in the treatment of cervical disc disease. Neurosurgery 2002;51:1343-50.
Topuz K, Colak A, Kaya S, Simşek H, Kutlay M, Demircan MN, et al
. Two-level contiguous cervical disc disease treated with peek cages packed with demineralized bone matrix: Results of 3-year follow-up. Eur Spine J 2009;18:238-43.
Pirkle S, Kaskovich S, Cook DJ, Ho A, Shi LL, Lee MJ. Cages in ACDF are associated with a higher nonunion rate than allograft: A stratified comparative analysis of 6130 patients. Spine (Phila Pa 1976) 2019;44:384-8.
Krause KL, Obayashi JT, Bridges KJ, Raslan AM, Than KD. Fivefold higher rate of pseudarthrosis with polyetheretherketone interbody device than with structural allograft used for 1-level anterior cervical discectomy and fusion: Presented at the 2018 AANS/CNS Joint Section on Disorders of the Spine and Peripheral Nerves. J Neurosurg Spine 2018;1:1-6.
Barber SM, Radaideh M, Parrish R. Efficacy of autogenous bone marrow aspirate as a fusion-promoting adjunct to anterior cervical discectomy and fusion: A single center retrospective cohort study. Cureus 2018;10:e2636.
Song KJ, Yoon SJ, Lee KB. Three-and four-level anterior cervical discectomy and fusion with a PEEK cage and plate construct. Eur Spine J 2012;21:2492-7.
[Figure 1], [Figure 2], [Figure 3], [Figure 4]