Clinical, radiological and histological study of the failure of cervical interbody fusions with bone substitutes

Biological aspects to enhance fracture healing

The ability to enhance fracture healing is paramount in modern orthopaedic trauma, particularly in the management of challenging cases including peri-prosthetic fractures, non-union and acute bone loss. Materials utilised in enhancing fracture healing should ideally be osteogenic, osteoinductive, osteoconductive, and facilitate vascular in-growth. Autologous bone graft remains the gold standard, providing all of these qualities. Limitations to this technique include low graft volume and donor site morbidity, with alternative techniques including the use of allograft or xenograft. Artificial scaffolds can provide an osteoconductive construct, however fail to provide an osteoinductive stimulus, and frequently have poor mechanical properties. Recombinant bone morphogenetic proteins can provide an osteoinductive stimulus; however, their licencing is limited and larger studies are required to clarify their role. For recalcitricant non-unions or high-risk cases, the use of composite graft combining the above techniques provides the highest chances of successfully achieving bony union.

Long-term results comparison after anterior cervical discectomy with BGS-7 spacer (NOVOMAX®-C) and allograft spacer: A prospective observational study

Introduction: In an anterior cervical discectomy and fusion (ACDF), various types of graft materials including autograft, allograft, and synthetic graft have been used to achieve adequate spinal fusion. Allograft spacer is mainly used in cervical fusion, especially in the anterior approach. The synthetic bone graft material BGS-7(CaO-SiO2-P2O5-B2O3, bioactive Glass-Ceramics) can bind with surrounding bone tissue by forming a hydroxyapatite layer bone bridge, leading to faster graft osseointegration. This study was conducted to compare long-term clinical outcome of BGS-7 spacer and allograft spacer for anterior cervical discectomy and fusion surgery. Materials and Methods: From September 2014 to December 2016, Consecutive anterior cervical discectomy and fusion surgeries using a BGS-7 spacer (N = 18) and Allograft spacer (N = 26) were compared for postoperative clinical outcomes. Radiologic assessments were performed, and Instrumental failure, including breakage, cage migration, subsidence were observed and Fusion status were analyzed. Finite element analysis was performed for simulating mechanical stress between the vertebral body and implant. Clinical outcomes were evaluated using neck VAS, NDI, and JOA on the patient's final follow-up visits. Results: Among the 44 patients who underwent an anterior cervical discectomy and fusion surgery using the BGS-7 spacer and Allograft spacer, there were 30 men and 14 women. The average age at the operation was 47.69 ± 10.49 in allograft spacer and 51.67 ± 11.03 in BGS-7 spacer. The mean follow-up period was 89.18 ± 5.44 months. Twenty three (88.46%) patients in allograft spacer and 20(100%) patients in BGS-7 spacer were demonstrated radiologic evidence of interbody fusion in last OPD, which accounts for fusion grade 4 or 5. Peak stresses were 343.85 MPa in allograft spacer, and 132.55 MPa in BGS-7 spacer. Long-term clinical outcomes including neck VAS, NDI, and JOA didn't show statistical differences between the two groups. There were no adverse events related to the BGS-7 spacer.10.3389/fbioe.2023.110046. Conclusion: The BGS-7 spacer demonstrated reliability as a spacer in anterior cervical discectomy and fusionF surgery without instrumental failure. Early stabilization with a bony bridge formation was observed at the intermediate follow-up period, and the long-term clinical outcome was favorable at more than 60 months after surgery without any adverse events. Thus, the BGS-7 spacer is a safe and effective alternative to the allograft spacer in anterior cervical discectomy and fusion surgery.

Clinical Application of Ceramics in Anterior Cervical Discectomy and Fusion: A Review and Update

STUDY DESIGN

Narrative review.

OBJECTIVES

Anterior cervical discectomy and fusion (ACDF) is a reliable procedure, commonly used for cervical degenerative disc disease. For interbody fusions, autograft was the gold standard for decades; however, limited availability and donor site morbidities have led to a constant search for new materials. Clinically, it has been shown that calcium phosphate ceramics, including hydroxyapatite (HA) and tricalcium phosphate (TCP), are effective as osteoconductive materials and bone grafts. In this review, we present the current findings regarding the use of ceramics in ACDF.

METHODS

A review of the relevant literature examining the clinical use of ceramics in anterior cervical discectomy and fusion procedures was conducted using PubMed, OVID and Cochrane.

RESULT

HA, coralline HA, sandwiched HA, TCP, and biphasic calcium phosphate ceramics were used in combination with osteoinductive materials such as bone marrow aspirate and various cages composed of poly-ether-ether-ketone (PEEK), fiber carbon, and titanium. Stand-alone ceramic spacers have been associated with fracture and cracks. Metallic cages such as titanium endure the risk of subsidence and migration. PEEK cages in combination with ceramics were shown to be a suitable substitute for autograft.

CONCLUSION

None of the discussed options has demonstrated clear superiority over others, although direct comparisons are often difficult due to discrepancies in data collection and study methodologies. Future randomized clinical trials are warranted before definitive conclusions can be drawn.

Is tutobone an efficient alternative to other implants used in anterior cervical discectomy and fusion surgeries?

BACKGROUND

The graft site morbidity following iliac crest harvesting is significant. To overcome this, different bone substitutes like coral dowels, solvent dissolved bovine/human bone substitutes, and carbon fiber/titanium cages have been used. This study was undertaken to assess the postoperative radiological fusion rates and symptom relief in patients who had Tutobone used as an interbody spacer compared to autologous bone graft (ABG), cages, surgibone and coral dowels.

METHODS

This was a retrospective, observational study. Case notes and post-operative cervical spine radiographs done at two subsequent follow-ups were reviewed. Data were derived from all Anterior Cervical Discectomy and fusion (ACDF) surgeries performed at our centre over a 10-year period for degenerative cervical spine disease. We analysed 530 patients. Exclusion criteria included incomplete notes, complex cervical surgery (both anterior and posterior fixation and vertebrectomies). Patients were divided into 3 groups, patients treated with (1) Autologous bone graft, (2) Tutobone and (3) other implants which include cages, surgibone and coral dowels.

RESULTS

An analysis of 530 patients who had ACDF with either ABG (n = 328) or tutobone (n = 95) or other implants (n = 90) is presented. A significantly greater number of patients in whom autologous bone was used had more than one level surgery. The median follow-up times were 3 months and 12 months. Rates of fusion and time to fusion with bone substitutes were inferior to ABG in our series, but there was not much to choose amongst them.

CONCLUSION

The use of ABG in ACDF leads to fusion in a shorter duration and greater proportion of patients, when compared to substitutes. Other implants like Tutobone (cheaper alternative), cages, etc can also be used in ACDF procedures with good efficacy with the added advantage of preventing donor site morbidity. There was no association between fusion rates and symptom relief and between use of plating and fusion.

A new source of autograft bone for interbody fusion in anterior cervical discectomy and fusion surgery: experience in 893 cases

PURPOSE

This study is to share our experience of a modified anterior cervical discectomy and fusion (ACDF) procedure with a new source of autograft bone for interbody fusion.

METHODS

The same procedure was performed in 893 cases where autograft was obtained from the osteophytes and/or the reams of vertebrae. For each case, radiological fusion rate and clinical outcome were followed up for 3 and 12 months after surgery.

RESULTS

For one to three-level ACDF, fusion rates were from 67.8% to 75.4% at 3 months follow-up, and 92% to 98.8% at 12 months follow-up. Patients' VAS, NDI, JOA and SF-36 score improve significantly at 12 months follow-up.

CONCLUSION

Osteophytes and vertebral reams can be a reliable source of bone graft that leads to high fusion rate and successful clinical outcome while avoiding all the problems with the current bone grafting methods used in ACDF surgery.

Current concepts of anterior cervical discectomy and fusion: a review of literature

Anterior cervical discectomy and fusion (ACDF) is a safe and effective procedure for degenerative cervical spinal disease unresponsive to conservative management and its outstanding results have been reported. To increase fusion rates and decrease complications, numerous graft materials, cage, anterior plating and total disc replacement have been developed, and better results were reported from those, but still there are areas that have not been established. Therefore, we are going to analyze the treatment outcome with the various procedure through the literature review and determine the efficacy of ACDF.

Anterior cervical interbody fusion using polyetheretherketone cage filled with autologous and synthetic bone graft substrates for cervical spondylosis: comparative analysis between PolyBone® and iliac bone

Clinical and radiological outcomes of cervical interbody fusion using a polyetheretherketone cage filled with PolyBone(®) (Kyungwon Medical Co., Ltd., Seoul, Korea), beta-tricalcium phosphate material, and autologous iliac bone were retrospectively compared in 47 patients who underwent anterior cervical discectomy and fusion (ACDF) between January 2007 and April 2008. Of these, 23 received iliac bone grafts and 24 received PolyBone. Numeric rating scale and neck disability index were used for clinical outcome assessments. Cervical radiography was performed immediately postoperatively, and at 1, 3, 6, 12, and 24 months postoperatively. Computed tomography (CT) was performed at 12 and 24 months postoperatively. Change in segmental lordosis, disk height, and fusion were compared at 12 and 24 months postoperatively. Clinical outcomes were similar between both groups. CT and radiography at 12 months showed that fusion had occurred in 22 patients in the iliac bone group and in 19 in the PolyBone recipients. Fusion was also identified in 22 patients in both iliac bone and PolyBone groups at 24 months postoperatively. The clinical outcomes of ACDF using PolyBone and iliac bone were similar, with similar cervical interbody fusion rates at 24 months postoperatively. However, the time taken for fusion was apparently longer in the PolyBone group.

Tissue-engineered bone formation in vivo for artificial laminae of the vertebral arch using β-tricalcium phosphate bioceramics seeded with mesenchymal stem cells

STUDY DESIGN

A rabbit laminectomy model was used to evaluate the efficacy of artificial laminae of vertebral arch using bone marrow-derived mesenchymal stem cells (MSCs) transplanted in porous beta-calcium phosphates (β-TCP) bioceramics.

OBJECTIVE

The aim of this study was to establish artificial lamina of the vertebral arch for bone tissue engineering using β-TCP bioceramics seeded with MSCs in a rabbit model of decompressive laminectomy.

SUMMARY OF BACKGROUND DATA

Decompressive laminectomy may induce various degrees of scar tissue and adhesion formation in the epidural space, and thus is the most common cause of failed back surgery syndrome. However, there is no effective method of bone defect treatment to control and reduce the scar tissue formation.

METHODS

MSCs were harvested from New Zealand rabbits (2-week old) by femoral bone marrow extraction. These cells were seeded into porous β-TCP bioceramics and cultivated for up to 3 weeks in the presence of osteogenic supplements. Segmental defects (20 × 8 mm) were created in 48 adult New Zealand rabbits that underwent laminectomy at the L5 to L6 levels. The animals were transplanted with cell media (control), β-TCP bioceramics (group I), or MSC-loaded β-TCP bioceramics (group II). Bone formation was evaluated after operation using scanning electron microscopy, computed tomography, magnetic resonance imaging, histomorphometry, and immunohistochemistry.

RESULTS

Scanning electron microscopy showed that MSCs filled the pores and surfaces of bioceramics in MSC-loaded β-TCP. In addition, significant increases in bone formation were observed in group II compared with other groups. Computed tomography and magnetic resonance imaging at 16 weeks showed that the artificial lamina of the vertebral arch was successfully formed. Hematoxylin-eosin and Masson trichrome staining were used to show the artificial laminae of the vertebral arch and the degraded bioceramics. In addition, immunohistochemistry results showed that the expression of bone morphogenetic protein-2 increased significantly in group II compared with group I at 2,4, and 8 weeks after implantation (P < 0.05).

CONCLUSION

β-TCP bioceramics seeded with MSCs are a promising source of tissue-engineered bone for the artificial lamina of the vertebral arch.

The effect of amorphous pyrophosphate on calcium phosphate cement resorption and bone generation

Pyrophosphate ions are both inhibitors of HA formation and substrates for phosphatase enzymes. Unlike polyphosphates their hydrolysis results simultaneously in the complete loss of mineral formation inhibition and a localised elevation in orthophosphate ion concentration. Despite recent advances in our knowledge of the role of the pyrophosphate ion, very little is known about the effects of pyrophosphate on bone formation and even less is known about its local delivery. In this work we first developed a self setting pyrophosphate based calcium cement system with appropriate handling properties and then compared its in vivo degradation properties with those of a non-pyrophosphate containing control. Contrary to expectation, the presence of the pyrophosphate phase in the cement matrix did not inhibit mineralisation of the healing bone around the implant, but actually appeared to stimulate it. In vitro evidence suggested that enzymatic action accelerated dissolution of the inorganic pyrophosphate ions, causing a simultaneous loss of their mineralisation inhibition and a localised rise in supersaturation with respect to HA. This is thought to be a rare example of a biologically responsive inorganic material and these materials seem to be worthy of further investigation. Bioceramics to date have mainly been limited to orthophosphate, silicate and carbonate salts of calcium, here we report the successful application of a pyrophosphate material as a degradable osteoconductive bone repair cement.

Comparison of 3 fusion techniques in the treatment of the degenerative cervical spine disease. Is stand-alone autograft really the "gold standard?": prospective study with 2-year follow-up

STUDY DESIGN

A prospective study.

OBJECTIVE

The aim of this study was to compare the 3 different methods of interbody fusion of the cervical spine-autograft in stand-alone technique, autograft with anterior plate, and polyetheretherketone cage supported by anterior plate. The clinical and radiological data obtained were analyzed and discussed.

SUMMARY OF BACKGROUND DATA

Although degenerative cervical spine disease has been treated by an anterior approach for more than 50 years, there is not one generally accepted operative approach. There is a very low-quality evidence of little or no difference in pain relief between each of the techniques. Iliac crest autograft still seems to be the "gold standard" for interbody fusion.

METHODS

Prospective study collecting clinical and radiological data of 81 patients undergoing anterior cervical interbody fusion, in which the interbody fusion of 1 or 2 motion segments from C3 to C7 was done by any of the 3 techniques--stand-alone insertion of autograft (group 1: 28 patients), autograft and anterior plate (group 2: 18 patients), and polyetheretherketone cage filled with beta-tricalcium phosphate and plate (group 3: 29 patients). Patients were followed for 2 years after surgery.

RESULTS

Significant interaction of relative height in the segment and time was found (P < 0.001). The values of the relative height of stand-alone autograft dropped below 95% of initial height and the values of the other 2 groups remained above 105%. Significant interaction of time and group was found for Cobb S angles (P < 0.001). Values of group 1 decreased substantially and remained significantly lower than values of other 2 groups. Fusion rate was 100% in all groups. Neck Disability Index group and time interaction was found (P = 0.023). During postoperative follow-up, group 1 scored in all controls higher than the other 2 groups, but differences were not significant. Visual analogue scale showed effect of time (P < 0.001). This was due to a smaller improvement of patients in group 1 during the whole follow-up in comparison with the other 2 groups. Highest proportion of unsatisfied patients was in group 1 compared with the other 2 groups after 2 years (P = 0.034).

CONCLUSION

Significantly worse radiological and clinical results after 2 years of follow-up were achieved using stand-alone autograft technique in comparison with autograft supported by anterior plating similarly as in comparison with cage implant and anterior plating. Using artificial fusion substrate together with plate and cage can offer the same clinical and radiological results such as iliac autograft and plating. Anterior plating seems to be an important factor influencing the postoperative cervical spine alignment and also the clinical outcome.

β-Tricalcium phosphate promotes bony fusion after anterior cervical discectomy and fusion using titanium cages

STUDY DESIGN

Retrospective consecutive cohort study.

OBJECTIVE

To study the effectiveness of β-tricalcium phosphate (β-TCP) granules as a packing material in the titanium cages for anterior cervical discectomy and fusion (ACDF), compared with the conventional hydroxyapatite (HA) granules.

SUMMARY OF BACKGROUND DATA

ACDF using titanium cages is a standard procedure for the treatment of cervical spinal degenerative diseases. Synthetic bone substitutes are widely used to pack the titanium cage to augment intervertebral bony fusion, but the efficacy has not been confirmed.

METHODS

Fusion condition was evaluated on lateral radiographs and computed tomography. Complete fusion of the treated segments was defined by three criteria: movement of the spinous process at flexion and extension positions of less than 3 mm, bony bridging between vertebral bodies, and absence of the halo around the titanium cage. The evaluation was performed at 6 months, 1 year, and 2 years after surgery.

RESULTS

Intervertebral fusion was studied in patients who underwent ACDF using β-TCP (93 segments of 57 patients) or HA (72 segments of 48 patients) packing of cylindrical titanium cages. Complete fusion rate at 6 months and 1 year was significantly better in the β-TCP group (46% at 6 months and 69% at 1 year) than in the HA group (24% at 6 months and 49% at 1 year), but the rate was similar at 2 years in the β-TCP group (94%) and the HA group (90%). There were no material-related adverse effects.

CONCLUSION

Satisfactory final fusion rates were obtained after ACDF using both β-TCP- and HA-packed titanium cages. β-TCP showed higher fusion rate in the early stage after surgery and can be recommended as a bone substitute for ACDF with titanium cages.

Comparative study of clinical outcomes of anterior cervical discectomy and fusion using autobone graft or cage with bone substitute

Study Design

A retrospective study.

Purpose

To compare the clinical and radiological outcomes of autogenous bone graft and cage with bone substitute for anterior cervical discectomy and fusion.

Overview of Literature

The clinical outcomes of cage with bone substitute for anterior cervical discectomy and fusion is satisfactory.

Methods

Eighty four patients who underwent cervical spine surgery between February 2004 and April 2009 were included. Fifty-nine patients were approached anteriorly and underwent anterior cervical discectomy and fusion by the Smith-Robinson method (Group A), and 25 patients underwent fusion by decompression of the cervical spine and cage with bone substitute (Group B). We measured and evaluated the postoperative period until patients were able to ambulate, for pre- and postoperative symptomatic improvement, postoperative complications, pre- and postoperative change of lordosis, degree of endplate collapse or subsidence, and fusion rate and period of union.

Results

By Robinson's criteria, respectively 45, 10 and 4 patients in Group A experienced excellent, good and fair symptomatic improvement, and respectively 19, 5 and 1 patients in Group B experienced excellent, good and fair symptomatic improvement. The postoperative period in which patients became ambulant and the period of hospital stay was significantly shorter in Group B. Increase of lordosis at final follow up after surgery was significantly larger in Group A, as was the fusion period. Significantly more endplate collapse occurred in Group B.

Conclusions

Of patients who had anterior cervical discectomy and fusion, results of both groups were both satisfactory.

Efficacy of PEEK cages and plate augmentation in three-level anterior cervical fusion of elderly patients

Background

To evaluate the clinical efficacy of three-level anterior cervical arthrodesis with polyethyletherketone (PEEK) cages and plate fixation for aged and osteoporotic patients with degenerative cervical spinal disorders.

Methods

Twenty one patients, who had undergone three-level anterior cervical arthrodesis with a cage and plate construct for degenerative cervical spinal disorder from November 2001 to April 2007 and were followed up for at least two years, were enrolled in this study. The mean age was 71.7 years and the mean T-score using the bone mineral density was -2.8 SD. The fusion rate, change in cervical lordosis, adjacent segment degeneration were analyzed by plain radiographs and computed tomography, and the complications were assessed by the medical records. The clinical outcomes were analyzed using the SF-36 physical composite score (PCS) and neck disability index (NDI).

Results

Radiological fusion was observed at a mean of 12.3 weeks (range, 10 to 15 weeks) after surgery. The average angle of cervical lordosis was 5° preoperatively, 17.6° postoperatively and 16.5° at the last follow-up. Degenerative changes in the adjacent segments occurred in 3 patients (14.3%), but revision surgery was unnecessary. In terms of instrument-related complications, there was cage subsidence in 5 patients (23.8%) with an average of 2.8 mm, and loosening of the plate and screw occurred in 3 patients (14.3%) but there were no clinical problems. The SF-36 PCS before surgery, second postoperative week and at the last follow-up was 29.5, 43.1, and 66.2, respectively. The respective NDI was 55.3, 24.6, and 15.9.

Conclusions

For aged and osteoporotic patients with degenerative cervical spinal disorders, three-level anterior cervical arthrodesis with PEEK cages and plate fixation reduced the pseudarthrosis and adjacent segment degeneration and improved the clinical outcomes. This method is considered to be a relatively safe and effective treatment modality.

Artrodese na coluna cervical utilizando SICAP como substituto de enxerto ósseo

OBJETIVO: Substitutos de enxerto ósseo autólogo foram desenvolvidos para evitar as complicações da retirada de enxerto ósseo autólogo. SiCaP (Actifuse, ApaTech EUA, Reino Unido) é um enxerto ósseo composto de cálcio-fosfato com um substituição de silicato na estrutura química, com uma estrutura tridimensional que parece osso natural. MÉTODOS: 19 pacientes foram submetidos à fusão óssea cervical e analisados retrospectivamente. A avaliação radiográfica e avaliação clínica foram realizadas utilizando o questionário Neck Disability Index e a escala análoga da dor (VAS) pré- e pós-operação. RESULTADOS: O período médio de acompanhamento pós-operatório foi de 14 meses ± 5 meses (7-30 meses). 11 pacientes foram submetidos à fusão via anterior; 5 pacientes via posterior e 3 pacientes via anterior e posterior. A revisão radiográfica mostrou 19/19 (100%) de fusão óssea, nenhum caso apresentou subsidência, quebra ou soltura de material de implante ou movimento nos níveis fusionados. Nenhum exemplo de ossificação heterotópica ou de crescimento ósseo intracanal foi observado. Clinicamente, os escores médios do Neck Disability decresceram 13,3 pontos (media pré-op. de 34,5, pós-op. de 21,2, melhora de 39%), a média da VAS para dor cervical decresceu 2 pontos (2,7 pré-op para 0,7 pós-op.; melhora de 74,1%). Não foram observadas complicações como infecção, osteólise ou edema excessivo das partes moles. CONCLUSÃO: Os resultados preliminares obtidos nesta série foram encorajadores com o uso do SICaP como enxerto ósseo, com sólida fusão óssea obtida em todos os casos e sem formação de ossificação heterotópica ou crescimento de osso intracanal. SIcaP demonstra ser um substituto confiável para o enxerto ósseo autólogo na coluna cervical.

Clinical result of sintered bovine hydroxyapatite bone substitute: analysis of the interface reaction between tissue and bone substitute

BACKGROUND

Autogenic bone graft is the first choice for managing bone defects. However, donor site-associated morbidity and limited bone volume are constraints in clinical applications. Allografts can provide sufficient amounts for bone defects but have a high risk of infection. Bone substitute composed of hydroxyapatite (HA) is an alternative material for avoiding the aforementioned risks. Sintered bovine bone is a naturally occurring HA that has been proved to have excellent bioactivity for inducing osteoblastic expression and new bone formation in animal studies. The objective of this study was to evaluate the interactions between the tissue and the bone substitute composed of HA (sintered from bovine bone) in the human body.

METHODS

From 2003 to 2005, a total of 33 patients were enrolled to receive the sintered bovine HA as a bone substitute. Inclusion criteria were fractures with bony defects, benign bone tumors with a cavity, and spinal fusions. Bone healing was monitored by a series of radiographs, and bone microstructure was checked by scanning electron microscopy (SEM) and von Kossa staining.

RESULTS

In 81.8% (27/33) of cases, significant fusion mass formation was visible in the radiographs after 6-12 months. New bone formation on the surface of the sintered bovine HA was seen under microscopic observation. Tight bonding between the interface of the bone and the sintered bovine HA was shown with SEM/energy-dispersive spectroscopy and von Kossa staining.

CONCLUSIONS

Sintered bovine HA is a suitable material as a bone substitute to provide bone growth and promote bone healing.

Plate augmentation in anterior cervical discectomy and fusion with cage for degenerative cervical spinal disorders

Anterior cervical discectomy and fusion (ACDF) with cage alone (ACDF-C) is associated with a significant incidence of subsidence, local kyphosis, and migration. The use of concurrent plate augmentation may decrease the incidence of these complications while improving the fusion rate. The purpose of the study is to present our results with ACDF with cage and plate augmentation (ACDF-CPA) and to compare these results to previous reports of outcomes following ACDF-C. We evaluated the radiologic and clinical parameters of 83 patients (266 fusion sites) who had an ACDF-CPA between March 2002 and May 2006. Radiologic parameters included fusion rate, fusion time, fusion type, site of pseudoarthrosis and rate and degree of subsidence. Clinical parameters included complications and overall outcomes assessed with Robinson's criteria; 79 of 83 patients showed bony fusion (95.1%) at last follow-up postoperatively, and there was no significant difference in fusion rate between the number of fusion levels. Type I (pseudoarthrosis) was noticed in 9 patients (12 fusion sites), type II in 14 (19 fusion sites), and type III in 60 (235 fusion sites). Five type I and all type II fusions converged into type III by the last follow-up; 76 of 83 patients (91.6%) experienced good clinical outcomes. Pseudoarthrosis occurred more commonly in more proximal locations, and the subsidence rate was significantly greater in two-level fusions when compared with single-level fusions (P = 0.046). There were four metal-related complications. Plate augmentation in one- or two-level anterior cervical fusions for degenerative cervical spine disorders may improve fusion rates and reduce subsidence and complication rates, resulting in improved clinical outcomes.

Usefulness of polyetheretherketone (PEEK) cage with plate augmentation for anterior arthrodesis in traumatic cervical spine injury

BACKGROUND CONTEXT

Even though many clinical reports about cages have been documented in patients with degenerative disorders, reports were scarce for traumatic injury cases, and those cases using metal cages were restricted to only one-level injury.

PURPOSE

To evaluate the usefulness of polyetheretherketone (PEEK) cage and plate construction in anterior interbody fusions (AIF) for traumatic cervical spine injuries by analyzing radiographic changes and clinical outcomes.

STUDY DESIGN/SETTING

Retrospective study.

PATIENT SAMPLE

Fifty-eight patients (91 levels) underwent cage and plate construction for treatment of traumatic cervical spine injury.

OUTCOME MEASURES

The fusion rate, fusion time, changes of Cobb angle, subsidence rate, and adjacent level changes were assessed as a radiographic outcome. Clinical analysis includes the recovery rate on the American Spinal Injury Association (ASIA) impairment scale and the presence of the complications.

METHODS

We evaluated 58 patients (91 levels) who underwent surgery and had at least 24 months in follow-up study. Radiographic evaluation included the assessment of interbody fusion rate, fusion time, changes of Cobb angle, subsidence rate, and adjacent level changes. Clinical assessment was done by analyzing recovery state of ASIA impairment scale from preoperative period to the last follow-up and by evaluating complications.

RESULTS

Fifty-four cases showed bony fusion within 3 months after the surgery. The mean Cobb angle between the vertebral bodies was 2.54 degrees before operation, 9.13 degrees after operation, and 8.39 degrees at the latest follow-up. The mean intervertebral disc height was increased by 3.01 mm after the operation, but the mean height was 2.17 mm shorter at the last follow-up than after postoperation. In terms of clinical results, five Grade A cases and one Grade B case as assessed by the ASIA impairment scale were unchanged until the last follow-up. Twenty-three cases of Grade C, 16 cases of Grade D, and 13 cases of Grade E improved to seven cases, 26 cases, and 19 cases, respectively. Three cases went through additional surgery, two posterior fusions for delayed union and posterior instability and one AIF for adjacent level disease.

CONCLUSION

The PEEK cage and additional plate fixation is a surgical procedure that decreases donor site morbidity, obtains high fusion rate with rigid fixation, and provides satisfactory clinical outcome for traumatic cervical spine injuries, regardless of the numbers of the involved levels.

Anterior cervical interbody fusion with hydroxyapatite graft: clinical and radiological analysis of graft breakage

STUDY DESIGN

Prospective longitudinal cohort.

OBJECTIVE

To evaluate the efficacy of hydroxyapatite (HA) grafts in combination with cervical plates in terms of fusion, restoration, and maintenance of cervical lordosis and to compare clinical and radiologic outcomes of patients who experienced graft breakage with patients who did not.

SUMMARY OF BACKGROUND DATA

The most common complication related to the use of HA graft for cervical anterior fusion is graft breakage. However, the implication of graft breakage in terms of loss of graft height, cervical alignment, plate migration, and clinical outcomes has not been adequately evaluated.

METHODOLOGY

A prospective study of 40 patients who underwent anterior cervical fusion in which HA graft and plate systems were used. Clinical and radiologic assessments were made 1 month after surgery and again at the final follow-up.

RESULTS

At the final follow-up evaluation, 80% of patients had an excellent clinical outcome, 15% had a good outcome, and 5% had a fair outcome based on Odom's classification. All patients achieved lordotic alignment in the immediate postoperative period. Graft breakage was observed in 25% of cases. Patients who experienced HA block breakage have 21 times more chance to have intervertebral height loss greater than 2 mm, 4.9 times more likely to undergo loss of cervical alignment exceeding 3 degrees, and 12.4 times more likely to present migration of the plates when compared to patients who had normal HA grafts.

CONCLUSION

Despite the positive clinical results observed in this study, breakage of HA grafts was a common complication occurring in 25% of patients. Graft breakage was associated with strut height loss of more than 2 mm, loss of cervical alignment exceeding 3 degrees and a higher rate of plate migration. These changes related to the HA graft breakage demonstrate the necessity to continue searching for better grafting methods to perform cervical interbody fusion.

Bone graft substitutes in anterior cervical discectomy and fusion

Anterior cervical discectomy with fusion is a common surgical procedure for patients suffering pain and/or neurological deficits and unresponsive to conservative management. For decades, autologous bone grafted from the iliac crest has been used as a substrate for cervical arthrodesis. However patient dissatisfaction with donor site morbidity has led to the search for alternative techniques. We present a literature review examining the progress of available grafting options as assessed in human clinical trials, considering allograft-based, synthetic, factor- and cell-based technologies.

Incorporation and immunogenicity of cleaned bovine bone in a sheep model

This study was conducted to determine if a novel cleaning process could extract antigenic material from bovine bone thereby improving incorporation. Cleaned bovine xenograft, untreated bovine xenograft and sheep allograft were implanted into the tibia of mature sheep for 12 and 24 weeks. Inflammation, bone integration and immunological reactions were evaluated via standardized assays. Cleaned bovine bone dowels induced significantly lower inflammatory responses (p < 50.05) when compared to traditionally processed xenograft. Bone integration, measured by in situ biomechanics, was not different between cleaned bovine bone and allograft controls (p = 0.96). A transient antibody response was observed for non-treated xenografts although this response abated by 3 months.

Anterior cervical fusion with interbody cage containing beta-tricalcium phosphate augmented with plate fixation: a prospective randomized study with 2-year follow-up

A variety of bone graft substitutes, interbody cages, and anterior plates have been used in cervical interbody fusion, but no controlled study was conducted on the clinical performance of beta-tricalcium phosphate (beta-TCP) and the effect of supplemented anterior plate fixation. The objective of this prospective, randomized clinical study was to evaluate the effectiveness of implanting interbody fusion cage containing beta-TCP for the treatment of cervical radiculopathy and/or myelopathy, and the fusion rates and outcomes in patients with or without randomly assigned plate fixation. Sixty-two patients with cervical radiculopathy and/or myelopathy due to soft disc herniation or spondylosis were treated with one- or two-level discectomy and fusion with interbody cages containing beta-TCP. They were randomly assigned to receive supplemented anterior plate (n = 33) or not (n = 29). The patients were followed up for 2 years postoperatively. The radiological and clinical outcomes were assessed during a 2-year follow-up. The results showed that the fusion rate (75.0%) 3 months after surgery in patients treated without anterior cervical plating was significantly lower than that (97.9%) with plate fixation (P < 0.05), but successful bone fusion was achieved in all patients of both groups at 6-month follow-up assessment. Patients treated without anterior plate fixation had 11 of 52 (19.2%) cage subsidence at last follow-up. No difference (P > 0.05) was found regarding improvement in spinal curvature as well as neck and arm pain, and recovery rate of JOA score at all time intervals between the two groups. Based on the findings of this study, interbody fusion cage containing beta-TCP following one- or two-level discectomy proved to be an effective treatment for cervical spondylotic radiculopathy and/or myelopathy. Supplemented anterior plate fixation can promote interbody fusion and prevent cage subsidence but do not improve the 2-year outcome when compared with those treated without anterior plate fixation.