Anterior interbody fusion of the cervical spine with coralline hydroxyapatite

Hydroxyapatite Use in Spine Surgery—Molecular and Clinical Aspect

Hydroxyapatite possesses desirable properties as a scaffold in tissue engineering: it is biocompatible at a site of implantation, and it is degradable to non-toxic products. Moreover, its porosity enables infiltration of cells, nutrients and waste products. The outcome of hydroxyapatite implantation highly depends on the extent of the host immune response. Authors emphasise major roles of the chemical, morphological and physical properties of the surface of biomaterial used. A number of techniques have been applied to transform the theoretical osteoconductive features of HAp into spinal fusion systems—from integration of HAp with autograft to synthetic intervertebral implants. The most popular uses of HAp in spine surgery include implants (ACDF), bone grafts in posterolateral lumbar fusion and transpedicular screws coating. In the past, autologous bone graft has been used as an intervertebral cage in ACDF. Due to the morbidity related to autograft harvesting from the iliac bone, a synthetic cage with osteoconductive material such as hydroxyapatite seems to be a good alternative. Regarding posterolateral lumbar fusion, it requires the graft to induce new bone growth and reinforce fusion between the vertebrae. Hydroxyapatite formulations have shown good results in that field. Moreover, the HAp coating has proven to be an efficient method of increasing screw fixation strength. It can decrease the risk of complications such as screw loosening after pedicle screw fixation in osteoporotic patients. The purpose of this literature review is to describe in vivo reaction to HAp implants and to summarise its current application in spine surgery.

Preparation of Coralline Hydroxyapatite Implant with Recombinant Human Bone Morphogenetic Protein-2-Loaded Chitosan Nanospheres and Its Osteogenic Efficacy

OBJECTIVE

Spinal fusion is one of the most common surgical interventions for spine reconstruction. Despite the efforts to promote osteogenesis after spinal fusion, osteogenesis after spinal fusion remains a clinical challenge and new methods are still needed. The bone morphogenetic protein-2 (BMP-2) is a widely reported factor that can facilitate the osteogenesis in spinal fusion. In previous research, we found that the delivery of chitosan nanospheres could promote the effects of BMP-2 on osteogenic activity. The coralline hydroxyapatite (CHA) is one of the most frequently used implants in bone fusion. However, up to now no study has focused on the osteogenic efficacy of the CHA composite with recombinant human BMP-2 (rhBMP-2)-loaded chitosan nanospheres. This study aimed to investigate the effects of the CHA implant with rhBMP-2-loaded chitosan nanospheres on osteogenesis in spinal fusion.

METHODS

The rhBMP-2-loaded microspheres and CHA composite (rhBMP-2 microspheres/CHA) were prepared and were used for implantation of the rats. All SD rats were divided into four groups: the rhBMP-2 microspheres/CHA composite group (containing 0.5 mg rhBMP-2), the rhBMP-2-loaded CHA (rhBMP-2/CHA) composite group (containing 0.5 mg rhBMP-2), the blank CHA group, and the negative control group. The microsphere morphology was scanned and analyzed using a scanning electron microscope. Micro-computed tomography examination and three-dimensional reconstruction were performed 4 weeks after the surgery. Hematoxylin and eosin staining was conducted for histological analysis. Both alkaline phosphatase (ALP) and calcium content were measured.

RESULTS

The rhBMP-2-loaded CHA (rhBMP-2/CHA) composite was successfully prepared. Spherical regularity and a smooth and unwrinkled surface of the spheres were observed in all chitosan (CS)/rhBMP-2 microspheres. No side effects, infections, or abnormal behaviors were found in the animals. After 4 weeks of surgery, obvious new bone formation and bone fusion could be observed around the implant in both the rhBMP-2 microspheres/CHA composite group and the rhBMP-2/CHA composite group. No ectopic osteogenesis was found in the vertebral canal or other muscle tissues. After 4 weeks of implantation, in both the rhBMP-2 microspheres/CHA composite group and the rhBMP-2/CHA composite group, osteoid tissues could be found, and bone cells, bone marrow, and trabecular bone turned into mature sclerotin, obvious bone tissue formation could be also seen. Both ALP activity and calcium content in the rhBMP-2 microspheres/CHA composite group (6.52 ± 0.50 kat/g and 17.54 ± 2.49 μg/mg) were significantly higher than in all other groups.

CONCLUSION

The composite with rhBMP-2-loaded CS nanospheres could enhance osteogenic efficacy and increase the ALP activity and calcium content. These results might provide a novel method for osteogenesis in spinal fusion and offer new insight into the role of BMP-2 in osteogenesis.

Complications of anterior cervical spine surgery: a systematic review of the literature

The anterior approach to the cervical spine is commonly utilized for a variety of degenerative, traumatic, neoplastic, and infectious indications. While many potential complications overlap with those of the posterior approach, the distinct anatomy of the anterior neck also presents a unique set of hazards. We performed a systematic review of the literature to assess the etiology, presentation, natural history, and management of these complications. Following the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA), a PubMed search was conducted to evaluate clinical studies and case reports of patients who suffered a complication of anterior cervical spine surgery. The search specifically included articles concerning adult human subjects, written in the English language, and published from 1989 to 2019. The PubMed search yielded 240 articles meeting our criteria. The overall rates of complications were as follows: dysphagia 5.3%, esophageal perforation 0.2%, recurrent laryngeal nerve palsy 1.3%, infection 1.2%, adjacent segment disease 8.1%, pseudarthrosis 2.0%, graft or hardware failure 2.1%, cerebrospinal fluid leak 0.5%, hematoma 1.0%, Horner syndrome 0.4%, C5 palsy 3.0%, vertebral artery injury 0.4%, and new or worsening neurological deficit 0.5%. Morbidity rates in anterior cervical spine surgery are low. Nevertheless, the unique anatomy of the anterior neck presents a wide variety of potential complications involving vascular, aerodigestive, neural, and osseous structures.

Radiographic and CT Evaluation of Recombinant Human Bone Morphogenetic Protein-2-assisted Cervical Spinal Interbody Fusion

STUDY DESIGN

This was a retrospective study.

OBJECTIVE

To radiographically demonstrate the distinct fusion pattern of recombinant human bone morphogenetic protein-2 (rhBMP-2) in the setting of anterior cervical discectomy and fusion.

SUMMARY OF BACKGROUND DATA

Studies investigating spinal fusion assisted with rhBMP-2 have yielded promising results, suggesting rhBMP-2 is an efficacious alternative to iliac crest autografts. rhBMP-2-assisted spinal fusion both hastens healing and eliminates patient morbidity from iliac crest autograft. Unique to rhBMP-assisted spinal fusion is its distinct radiographic fusion pattern as fusion is achieved. Despite promising results and increased clinical use of rhBMP-2, there remains a paucity of literature documenting this radiographic process.

MATERIALS AND METHODS

This study included 26 patients who underwent single-level anterior cervical discectomy and fusion using rhBMP-2. All data used for this study was collected from a prior FDA Investigational Device Exemption study.

RESULTS

A polyetheretherketone cage was used as an interbody disk spacer in all 26 patients. Patients were evaluated between 2 and 6 weeks after surgery and subsequently at 3, 6, 12, and 24 months postoperative. All patients underwent plain radiography at every follow-up visit, and computed tomograhy evaluation was performed at 3, 6, 12, and 24 months as part of the study protocol. Earliest fusion was observed at 3 months in 38% of patients. Likely fusion was observed in all patients by 12 months postoperative.

CONCLUSIONS

rhBMP-2 leads to both successful interbody fusion and an enhanced fusion rate with unique imaging characteristics. Additional characteristics of BMP observed in 100% of patients included prevertebral soft-tissue swelling and early endplate resorption. Other common features included polyetheretherketone cage migration, heterotopic bone formation and cage subsidence.

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.

Fabrication of calcite blocks from gypsum blocks by compositional transformation based on dissolution-precipitation reactions in sodium carbonate solution

Calcium carbonate (CaCO₃) has been used as a bone substitute, and is a precursor for carbonate apatite, which is also a promising bone substitute. However, limited studies have been reported on the fabrication of artificial calcite blocks. In the present study, cylindrical calcite blocks (ϕ6×3mm) were fabricated by compositional transformation based on dissolution-precipitation reactions using different calcium sulfate blocks as a precursor. In the dissolution-precipitation reactions, both CaSO₄·2H₂O and CaSO₄ transformed into calcite, a polymorph of CaCO₃, while maintaining their macroscopic structure when immersed in 1mol/L Na₂CO₃ solution at 80°C for 1week. The diametral tensile strengths of the calcite blocks formed using CaSO₄·2H₂O and CaSO₄ were 1.0±0.3 and 2.3±0.7MPa, respectively. The fabrication of calcite blocks using CaSO₄·2H₂O and CaSO₄ proposed in this investigation may be a useful method to produce calcite blocks because of the self-setting ability and high temperature stability of gypsum precursors.

Bone Union Rate Following Instrumented Posterolateral Lumbar Fusion: Comparison between Demineralized Bone Matrix versus Hydroxyapatite

Study Design

Retrospective study.

Purpose

To compare the union rate of posterolateral lumbar fusion (PLF) using demineralized bone matrix (DBM) versus hydroxyapatite (HA) as bone graft extender.

Overview of Literature

To our knowledge, there has been no clinical trial to compare the outcomes of DBM versus HA as a graft material for PLF.

Methods

We analyzed prospectively collected data from consecutive 79 patients who underwent instrumented PLF. Patients who received DBM were assigned to group B (n=38), and patients who received HA were assigned into group C (n=41). The primary study outcome was fusion rate assessed with radiographs. The secondary outcomes included pain intensity using a visual analogue scale, functional outcome using Oswestry disability index score, laboratory tests of inflammatory profiles and infection rate.

Results

One year postoperatively, bone fusion was achieved in 73% in group B and 58% in group C without significant difference between the groups (p=0.15). There were no differences between the groups with respect to secondary outcomes.

Conclusions

DBM would provide noninferior outcomes compared to the HA as a fusion material for PLF, and could be a notable alternative.

Is there a role of coral bone substitutes in bone repair?

Xenogeneic bone graft materials are an alternative to autologous bone grafting. Among such implants, coralline-derived bone grafts substitutes have a long track record as safe, biocompatible and osteoconductive graft materials. In this review, we present the available literature surrounding their use with special focus on the commercially available graft materials. Corals thanks to their chemical and structural characteristics similar to those of the human cancellous bone have shown great potential but clinical data presented to date is ambiguous with both positive and negative outcomes reported. Correct formulation and design of the graft to ensure adequate osteo-activity and resorption appear intrinsic to a successful outcome.

Bone substitutes and expanders in Spine Surgery: A review of their fusion efficacies

STUDY DESIGN

A narrative review of literature.

OBJECTIVE

This manuscript intends to provide a review of clinically relevant bone substitutes and bone expanders for spinal surgery in terms of efficacy and associated clinical outcomes, as reported in contemporary spine literature.

SUMMARY OF BACKGROUND DATA

Ever since the introduction of allograft as a substitute for autologous bone in spinal surgery, a sea of literature has surfaced, evaluating both established and newly emerging fusion alternatives. An understanding of the available fusion options and an organized evidence-based approach to their use in spine surgery is essential for achieving optimal results.

METHODS

A Medline search of English language literature published through March 2016 discussing bone graft substitutes and fusion extenders was performed. All clinical studies reporting radiological and/or patient outcomes following the use of bone substitutes were reviewed under the broad categories of Allografts, Demineralized Bone Matrices (DBM), Ceramics, Bone Morphogenic proteins (BMPs), Autologous growth factors (AGFs), Stem cell products and Synthetic Peptides. These were further grouped depending on their application in lumbar and cervical spine surgeries, deformity correction or other miscellaneous procedures viz. trauma, infection or tumors; wherever data was forthcoming. Studies in animal populations and experimental in vitro studies were excluded. Primary endpoints were radiological fusion rates and successful clinical outcomes.

RESULTS

A total of 181 clinical studies were found suitable to be included in the review. More than a third of the published articles (62 studies, 34.25%) focused on BMP. Ceramics (40 studies) and Allografts (39 studies) were the other two highly published groups of bone substitutes. Highest radiographic fusion rates were observed with BMPs, followed by allograft and DBM. There were no significant differences in the reported clinical outcomes across all classes of bone substitutes.

CONCLUSIONS

There is a clear publication bias in the literature, mostly favoring BMP. Based on the available data, BMP is however associated with the highest radiographic fusion rate. Allograft is also very well corroborated in the literature. The use of DBM as a bone expander to augment autograft is supported, especially in the lumbar spine. Ceramics are also utilized as bone graft extenders and results are generally supportive, although limited. The use of autologous growth factors is not substantiated at this time. Cell matrix or stem cell-based products and the synthetic peptides have inadequate data. More comparative studies are needed to evaluate the efficacy of bone graft substitutes overall.

Efficacy of i-Factor Bone Graft versus Autograft in Anterior Cervical Discectomy and Fusion: Results of the Prospective, Randomized, Single-blinded Food and Drug Administration Investigational Device Exemption Study

STUDY DESIGN

A prospective, randomized, controlled, parallel, single-blinded noninferiority multicenter pivotal FDA IDE trial.

OBJECTIVE

The objective of this study was to investigate efficacy and safety of i-Factor Bone Graft (i-Factor) compared with local autograft in single-level anterior cervical discectomy and fusion (ACDF) for cervical radiculopathy.

SUMMARY OF BACKGROUND DATA

i-Factor is a composite bone substitute material consisting of the P-15 synthetic collagen fragment adsorbed onto anorganic bone mineral and suspended in an inert biocompatible hydrogel carrier. P-15 has demonstrated bone healing efficacy in dental, orthopedic, and nonhuman applications.

METHODS

Patients randomly received either autograft (N = 154) or i-Factor (N = 165) in a cortical ring allograft. Study success was defined as noninferiority in fusion, Neck Disability Index (NDI), and Neurological Success endpoints, and similar adverse events profile at 12 months.

RESULTS

At 12 months (follow-up rate 87%), both i-Factor and autograft subjects demonstrated a high fusion rate (88.97% and 85.82%, respectively, noninferiority P = 0.0004), significant improvements in NDI (28.75 and 27.40, respectively, noninferiority P < 0.0001), and high Neurological Success rate (93.71% and 93.01%, respectively, noninferiority P < 0.0001). There was no difference in the rate of adverse events (83.64% and 82.47% in the i-Factor and autograft groups, respectively, P = 0.8814). Overall success rate consisting of fusion, NDI, Neurological Success and Safety Success was higher in i-Factor subjects than in autograft subjects (68.75% and 56.94%, respectively, P = 0.0382). Improvements in VAS pain and SF-36v2 scores were clinically relevant and similar between the groups. A high proportion of patients reported good or excellent Odom outcomes (81.4% in both groups).

CONCLUSION

i-Factor has met all four FDA mandated noninferiority success criteria and has demonstrated safety and efficacy in single-level ACDF for cervical radiculopathy. i-Factor and autograft groups demonstrated significant postsurgical improvement and high fusion rates.

LEVEL OF EVIDENCE

1.

Comparison of the clinical and radiologic outcomes obtained with single- versus two-level anterior cervical decompression and fusion using stand-alone PEEK cages filled with allograft

BACKGROUND

Although anterior cervical decompression and fusion with a stand-alone cage (ACDF-SAC) is accepted as a suitable procedure, the outcomes of the multi-level procedure remain controversial. The aim of this study is to compare the clinical and radiologic outcomes achieved with single versus two-level ACDF-SAC along with identification of the factors that contribute to loss in mean disc height (MDH) and change in cervical lordotic angle (CLA).

METHODS

A total of 109 consecutive patients who underwent ACDF-SAC for degenerative spondylosis were reviewed. Patients were divided into two groups according to surgical level (group A, single; group B, two) and were followed for at least 1 year. Clinical outcomes were evaluated using the visual analog scale (VAS) and Robinson's criteria. The fusion and subsidence rates, MDH, CLA, anterior, and posterior vertebral body height of the fused segments (AVBH, PVBH) were measured retrospectively from plain radiographs.

RESULTS

Clinical outcomes were similar in both groups, in terms of decreasing VAS score and a grade higher than "good" by Robinson's criteria. The fusion and subsidence rates for each group were found to be 92.2, 91.1, 14.1, and 20.0 %, respectively. The MDH (mm) increased by 1.44 ± 0.96 in group A, 1.57 ± 0.79 and 1.66 ± 0.69 for each surgical level in group B over the 12 postoperative months. The CLA (°) decreased by 1.70 ± 4.04 and 0.75 ± 6.12 over the 12 postoperative months from its presurgery value, the rate of kyphosis >5° was 26.6 and 22.2 % for each group. All compared values were not significantly different between the two groups. Correlation analysis revealed that the AVBH/PVBH ratio exhibited a positive correlation with CLA change in both groups (r = 0.368, 0.397; p = 0.018, 0.040).

CONCLUSIONS

The overall outcomes achieved with two-level ACDF-SAC were similar to those achieved with single-level ones. In addition, the AVBH/PVBH ratio might be a predictable marker for a postoperative kyphosis.

Fabrication of porous calcite using chopped nylon fiber and its evaluation using rats

Although porous calcite has attracted attention as bone substitutes, limited studies have been made so far. In the present study, porous calcite block was fabricated by introducing chopped nylon fiber as porogen. Ca(OH)2 powder containing 10 wt% chopped nylon fiber was compacted at 150 MPa, and sintered to burn out the fiber and to carbonate the Ca(OH)2 under stream of 1:2 O2-CO2. Sintering of Ca(OH)2 at 750 °C or lower temperature resulted in incomplete burning out of the fiber whereas sintering at 800 °C or higher temperature resulted in the formation of CaO due to the thermal decomposition of Ca(OH)2. However, sintering at 770 °C resulted in complete burning out of the fiber and complete carbonation of Ca(OH)2 to calcite without forming CaO. Macro- and micro-porosities of the porous calcite were approximately 23 and 16%, respectively. Diameter of the macropores was approximately 100 μm which is suitable for bone tissue penetration. Porous calcite block fabricated by this method exhibited good tissue response when implanted in the bone defect in femur of 12-weeks-old rat. Four weeks after implantation, bone bonded on the surface of calcite. Furthermore, bone tissue penetrated interior to the macropore at 8 weeks. These results demonstrated the good potential value of porous calcite as artificial bone substitutes.

Zero-P: a new zero-profile cage-plate device for single and multilevel ACDF. A single institution series with four years maximum follow-up and review of the literature on zero-profile devices

PURPOSE

To analyze the prospectively collected data in a series of patients treated with single- or multilevel ACDF with a stand-alone, zero-profile device, focusing on clinico-radiological outcome, complications and technical hints, and to review the literature on such new devices.

METHODS

Eighty-five patients harboring symptomatic DDD underwent ACDF with the Zero-P cage-plate: 29 at 1-level and 56 at 2-4 levels (total 162 devices). In the multilevel group, 9 patients received a combination of Zero-P and stand-alone cages (hybrid implants). This study focuses on 32 patients with follow-up ranging from 20 to 48 months. NDI, SF-36 and arm pain VAS scores were registered preoperatively and at follow-up visits. Dysphagia was assessed using the Bazaz score. Imaging included X-rays, CT and MRI, also to assess the presence of vertebral body fractures in multilevel cases. Paired Student t test was used for statistical analysis.

RESULTS

SF-36 and NDI showed a statistically significant improvement (p < 0.01) and mean arm pain VAS score decreased from 79 to 41. X-rays and CT demonstrated, respectively, a 94.5 % and a 92 % fusion rate. Three patients complained of moderate and two of mild transient dysphagia (15.5 %). No device-related complications occurred and no fractures, secondary to four screws insertion in one vertebral body (i.e., swiss cheese effect), were detected in multilevel cases. In patients with extensive anterior osteophytes only a "focal spondylectomy" was required.

CONCLUSION

The Zero-P device is safe and efficient, even in multilevel cases. Dysphagia is minimal, extensive anterior osteophytectomy is unnecessary and technical hints may ease the surgical workflow. This is the largest series, with the longest follow-up, reported.

Calcium Orthophosphate-Based Bioceramics

Various types of grafts have been traditionally used to restore damaged bones. In the late 1960s, a strong interest was raised in studying ceramics as potential bone grafts due to their biomechanical properties. A bit later, such synthetic biomaterials were called bioceramics. In principle, bioceramics can be prepared from diverse materials but this review is limited to calcium orthophosphate-based formulations only, which possess the specific advantages due to the chemical similarity to mammalian bones and teeth. During the past 40 years, there have been a number of important achievements in this field. Namely, after the initial development of bioceramics that was just tolerated in the physiological environment, an emphasis was shifted towards the formulations able to form direct chemical bonds with the adjacent bones. Afterwards, by the structural and compositional controls, it became possible to choose whether the calcium orthophosphate-based implants remain biologically stable once incorporated into the skeletal structure or whether they were resorbed over time. At the turn of the millennium, a new concept of regenerative bioceramics was developed and such formulations became an integrated part of the tissue engineering approach. Now calcium orthophosphate scaffolds are designed to induce bone formation and vascularization. These scaffolds are often porous and harbor different biomolecules and/or cells. Therefore, current biomedical applications of calcium orthophosphate bioceramics include bone augmentations, artificial bone grafts, maxillofacial reconstruction, spinal fusion, periodontal disease repairs and bone fillers after tumor surgery. Perspective future applications comprise drug delivery and tissue engineering purposes because calcium orthophosphates appear to be promising carriers of growth factors, bioactive peptides and various types of cells.

Porous/dense composite hydroxyapatite for anterior cervical discectomy and fusion

STUDY DESIGN

A prospective analysis

OBJECTIVE

Our aim was to investigate the efficacy of new synthetic porous/dense composite hydroxyapatite (HA) for use in anterior cervical discectomy and fusion (ACDF).

SUMMARY OF BACKGROUND DATA

Iliac crest bone graft (ICBG) has been traditionally used as the "gold standard" for ACDF. The significant complication rate associated with harvesting tricortical ICBG, however, has encouraged development of alternative graft substitutes.

METHODS

The morphology of the porous/dense HA was observed by scanning electron microscopy (SEM), and the in vitro compressive strength of the composite HA was measured. From April 2005, 51 consecutive patients underwent 81 levels of ACDF using the composite HA with percutaneously harvested trephine bone chips. Clinical and radiological evaluation was performed during the postoperative hospital stay and at follow-up. Furthermore, the outcomes in ACDF using the composite HA were compared with those using tricortical ICBG.

RESULTS

The SEM images demonstrated 100- to 300-μm pores (approximately 40% of porosity) in the porous layers of the HA. The compressive strength of the composite HA was 203.1 ± 4.1 MPa. In the clinical study, the demographic data of the patients were similar in HA and ICBG groups. The fusion rates in HA group were comparable with those in ICBG group. The cervical lordosis was enhanced postoperatively in both groups and well preserved at 2-year follow-up without significant differences between the groups. The intraoperative blood loss in HA group was significantly lesser than that in ICBG group. Donor site complications were found in 29.2% of the patients in ICBG group, whereas no donor site morbidity was found in HA group. No major collapse or fragmentation of the composite HA was found.

CONCLUSION

The hybrid graft of composite HA and percutaneously harvested trephine chips seemed promising as a graft substitute for ACDF.

LEVEL OF EVIDENCE

4.

Backfilling of iliac crest defects with hydroxyapatite-calcium triphosphate biphasic compound: a prospective, randomized computed tomography and patient-based analysis

BACKGROUND CONTEXT

Hydroxyapatite-calcium triphosphate (HCT) biphasic compounds are known to be efficacious in filling bone voids. No large study to date has assessed their radiographic efficacy in iliac crest voids with computed tomography (CT) analysis at a 2-year follow-up.

PURPOSE

To assess whether backfilling iliac crest defects with HCT biphasic compound decreases donor site pain and what effect backfilling has on CT appearance of the donor ilium.

STUDY DESIGN

Prospective randomized clinical trial.

PATIENT SAMPLE

Adult patients with spinal disorders undergoing spinal arthrodesis requiring posterior iliac crest bone grafting.

OUTCOME MEASURES

Physician-administered visual analog scale (VAS) and pre- and postoperative CT analysis was performed.

METHODS

This prospective, randomized, single-blind study followed patients requiring nonstructural posterior iliac crest harvest as part of spinal disorder treatment for 2 years. The harvest technique preserved both cortical tables and their periostea. All patients were randomized to backfill of HCT or no backfill. All patients had a CT of the pelvis immediately postoperative and at the 2-year follow-up. Computed tomography analysis was performed by a board-certified neuroradiologist. Analysis included qualitative assessment of the ilia appearance and defect density quantified in Hounsfield units. All patients completed VAS of their donor site pain (0-10, from low to high) at 6 weeks and 2 years postoperatively.

RESULTS

Thirty-seven of 40 (17 women and 20 men) subjects returned for a mean 23.9-month follow-up (range, 22-29 months). The average age was 51.7 years (range, 27-79 years). Eighteen patients were in the backfill group (BF) and 19 were in the control group (C). There was no statistically significant difference in pain at 6 weeks or 2 years between the two groups. Bone density significantly decreased from postoperative to 2 years in BF (implying resorption of HCT and replacement of host bone) and significantly increased in C (implying reformation of host bone). Both groups had similar cortical defect repair. The backfill group had significantly better medullary defect repair (p<.01, Fisher exact test).

CONCLUSIONS

Backfilling iliac crest voids with HCT biphasic compound does not significantly decrease donor site pain. Both the backfilled and control defects reformed bone over the 2-year period, with BF having significantly less medullary defects than C.

Silicate-substituted calcium phosphate ceramic bone graft replacement for spinal fusion procedures

STUDY DESIGN

Retrospective study.

OBJECTIVE

To assess the clinical and radiographical outcomes in spinal fusion procedures using silicate-substituted calcium phosphate (Si-CaP).

SUMMARY OF BACKGROUND DATA

Si-CaP is a newer-generation synthetic ceramic designed to maximize osteoinduction and osteoconduction.

METHODS

This is a retrospective analysis of a prospectively collected patient database including 108 patients (204 individual spinal levels). Different surgical procedures performed included 25 anterior cervical discectomy and fusions, 17 posterior cervical fusions, 7 combined anterior and posterior cervical fusions, 10 thoracic fusion surgeries, 18 transforaminal lumbar interbody fusions with 12 axial lumbar interbody fusions, 11 transpsoas discectomy and fusions, and 8 combined thoracolumbar fusion procedures. Si-CaP was used as bone extender without any additional graft material, bone marrow aspirate, or bone morphogenetic protein. Clinical outcomes were assessed using the visual analogue scale (VAS), Oswestry Disability Index, and Neck Disability Index. Fusion was determined by the presence of bony bridging on 2 consecutive sections in at least 2 planes on computed tomographic imaging.

RESULTS

At a follow-up of 12 (± 4.7) months, 90% of all patients demonstrated radiographical fusion. Fusion rates were highest in the cervical spine (97%) followed by thoracic and lumbar spines (86% and 81%, respectively). There were significant improvements in all clinical outcome measures-Oswestry Disability Index, 11.1 (± 10.2) and Neck Disability Index, 9.0 (± 11.4); VAS-back, 3.1(± 3.0); VAS-leg, 3.5 (± 3.6); VAS-neck, 3.7 (± 2.5); and VAS-arm 4.0 (± 3.2). There was no radiographical loosening of instrumentation due to infection or nonunion in this series, and no subsequent revisions for nonunion were required.

CONCLUSION

Si-CaP is an alternative to autogenous bone graft in spinal arthrodesis procedures. At 12-month follow-up, we detected high levels of bony fusion using Si-CaP in combination with various surgical spinal techniques.

Pain from donor site after anterior cervical fusion with bone graft: a prospective randomized study with 12 months of follow-up

INTRODUCTION

Harvesting bone graft from the iliac crest in spinal fusion surgery is a widely used technique. However, complications can occur and there are also reports of patients with persistent graft site pain after surgery. The aim of this study was to evaluate pain from the donor site (DS) over time, and register associated complications and if it affected health-related quality of life (HRQoL).

MATERIAL AND METHODS

One hundred and seven patients participating in an RCT between two different methods of reconstruction after cervical decompression were included in this study. One group underwent surgery with bone graft (BG) from the iliac crest and the other with no bone graft (NBG). All patients were evaluated concerning pain at DS and HRQoL preoperatively, at 4 weeks, 3 months and 1 year. Pain was evaluated with visual analog scale (VAS) and HRQoL with EQ-5D.

RESULTS

A statistically significant difference was found at all times of follow-up in the BG group compared to preoperative levels and the NBG group. The VAS levels at follow-ups at 3 months and 1 year were however of questionable clinical importance. Two patients in the BG group had superficial wound infections postoperatively and five patients still had sensory disturbance in the area of graft site at 12 months. No major complications were registered. No difference could be seen in EQ-5D at any time of follow-up between the groups.

CONCLUSION

Harvesting of iliac crest bone graft is associated with significant pain. However, at 3 months postoperatively, the negative effect of clinical importance seemed to have disappeared compared to when no bone graft was harvested. The pain from bone graft harvesting does not seem to affect the quality of life at 4 weeks postoperatively and onward.

Feasibility of anterior cervical discectomy and fusion as an outpatient procedure

BACKGROUND

Anterior cervical discectomy and fusion (ACDF) procedures are increasingly being managed on an outpatient basis. Currently there are no definitive guidelines within the literature that delineate which patient population can safely be managed as such. The purpose of this study is to demonstrate that ACDF procedures, within a selective patient population at our institution, can be safely performed on an outpatient basis.

METHODS

This is a retrospective chart review within one physician's practice of patients undergoing instrumented ACDF procedures using allograft. This sample included 117 patients who underwent one- and two-level ACDF procedures from November 2005 to April 2009. Hospital length of stay and hospital readmissions were noted. Complication rates in the outpatient population were assessed to determine the feasibility of outpatient management for selective patients undergoing ACDF procedures.

RESULTS

A total of 59 patients (50%) were treated on an outpatient basis. Sixty-eight patients underwent single level ACDF procedures, 38 patients (56%) of which were discharged on the same day. Forty-nine patients underwent two-level ACDF procedures, 21 patients (43%) of which were discharged on the same day. There was one complication (1.4%) in patients who were discharged on the same day. That patient required readmission for 23-hour observation secondary to neck swelling.

CONCLUSIONS

ACDF procedures involving single and two-level fusions can safely be performed on an outpatient basis. Complication rates associated with this procedure are low, with critical postoperative complications involving respiratory compromise occurring very infrequently and in the immediate postoperative period.

Bone substitutes in the Netherlands - a systematic literature review

Autologous bone grafting is currently considered as the gold standard to restore bone defects. However, clinical benefit is not guaranteed and there is an associated 8-39% complication rate. This has resulted in the development of alternative (synthetic) bone substitutes. The aim of this systematic literature review was to provide a comprehensive overview of literature data of bone substitutes registered in the Netherlands for use in trauma and orthopedic surgery. Brand names of selected products were used as search terms in three available databases: Embase, PubMed and Cochrane. Manuscripts written in English, German or Dutch that reported on structural, biological or biomechanical properties of the pure product or on its use in trauma and orthopedic surgery were included. The primary search resulted in 475 manuscripts from PubMed, 653 from Embase and 10 from Cochrane. Of these, 218 met the final inclusion criteria. Of each product, structural, biological and biomechanical characteristics as well as their clinical indications in trauma and orthopedic surgery are provided. All included products possess osteoconductive properties but differ in resorption time and biomechanical properties. They have been used for a wide range of clinical applications; however, the overall level of clinical evidence is low. The requirements of an optimal bone substitute are related to the size and location of the defect. Calcium phosphate grafts have been used for most trauma and orthopedic surgery procedures. Calcium sulphates were mainly used to restore bone defects after tumour resection surgery but offer minimal structural support. Bioactive glass remains a potential alternative; however, its use has only been studied to a limited extent.

Effect of hydroxyapatite on bone integration in a rabbit tibial defect model

Background

The aim of the present study was to prepare hydroxyapatite (HA) and then characterize its effect on bone integration in a rabbit tibial defect model. The bone formation with different designs of HA was compared and the bony integration of several graft materials was investigated qualitatively by radiologic and histologic study.

Methods

Ten rabbits were included in this study; two holes were drilled bilaterally across the near cortex and the four holes in each rabbit were divided into four treatment groups (HAP, hydroxyapatite powder; HAC, hydroxyapatite cylinder; HA/TCP, hydroxyapatite/tri-calcium phosphate cylinder, and titanium cylinder). The volume of bone ingrowth and the change of bone mineral density were statistically calculated by computed tomography five times for each treatment group at 0, 2, 4, 6, and 8 weeks after grafting. Histologic analysis was performed at 8 weeks after grafting.

Results

The HAP group showed the most pronounced effect on the bone ingrowth surface area, which seen at 4, 6, and 8 weeks after graft (p < 0.05). On comparing the change of bone mineral density the bone ingrowth surface area among the 4 groups, there were no statistically significant differences among the groups found for any period (p > 0.05). On histological examination, the HAP group revealed well-recovered cortical bone, but the bone was irregularly thickened and haphazardly admixed with powder. The HAC group showed similar histological features to those of the HA/TCP group; the cortical surface of the newly developed bone was smooth and the bone matrix on the surface of the cylinder was regularly arranged.

Conclusions

We concluded that both the hydroxyapatite powder and cylinder models investigated in our study may be suitable as a bone substitute in the rabbit tibial defect model, but their characteristic properties are quite different. In contrast to hydroxyapatite powder, which showed better results for the bone ingrowth surface, the hydroxyapatite cylinder showed better results for the sustained morphology.

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.

Clinical and radiological outcomes of anterior cervical interbody fusion using hydroxyapatite spacer

OBJECTIVE

This is retrospective study of clinical and radiological outcomes of anterior cervical fusion using Bongros-HA (BioAlpha, Seongnam, Korea) which is a type of synthetic hydroxyapatite (HA) spacer to evaluate the efficacy in its clinical application and usefulness as a reliable alternative to autograft bone.

METHODS

Twenty-nine patients were enrolled in this study and 40 segments were involved. All patients were performed anterior cervical interbody fusion using HA spacer and plating system. Indications for surgery were radiculopathy caused by soft-disc herniation or spondylosis in 18 patients, spondylotic myelopathy in 1 patient, and spinal trauma in 10 patients. Cervical spine radiographs were obtained on postoperative 1day, 1week, and then at 1, 2, 6, and 12 months in all patients to evaluate intervertebral disc height, and the degrees of lordosis. Cervical computed tomography was done at postoperative 12 month in all patients to confirm the fusion status. The mean period of clinical follow-up was 17 months.

RESULTS

Complete interbody fusion was achieved in 100% of patients. Preoperative kyphotic deformities were corrected in all cases after surgery. Intervertebral disc height was well maintained during follow up period. There were no cases of graft extrusion, graft deterioration and graft fracture.

CONCLUSION

HA spacer is very efficient in achieving cervical fusion, maintaining intervertebral disc height, and restoring lordosis. When combined with the placement of a cervical plate, immediate stability can be achieved and graft related complication can be prevented.

Coralline hydroxyapatite is a suitable bone graft substitute in an intra-articular goat defect model

Intra-articular defects can be filled with an autologous bone graft taken from the iliac crest. This can be indicated after trauma or following correcting osteotomy. Patients may encounter donor site morbidity after this procedure. In this in vivo study, we studied if coralline hydroxyapatite (CHA) is a suitable material to replace autologous bone graft to fill a defect in the femoral trochlea of goats. CHA did not evoke any negative reaction in the synovium, and the articular cartilage was comparable to controls. In the bone graft group, we found scattered areas of (enchondral formed) bone. Most bone graft had been resorbed or remodeled, and the scarce remnants were incorporated into new bone. Resorption of CHA was limited or absent and most CHA was surrounded by new bone. In areas with fragmented CHA, close to the joint surface, numerous giant cells were found. The study shows that in this animal model, CHA inserted in a defect that directly communicates with the joint space incorporates into bone. This study did not show any negative effects of CHA in a joint environment.

An update on bone substitutes for spinal fusion

With the current advances in spinal surgery, an understanding of the precise biological mechanism of each bone substitute is necessary for inducing successful spinal fusion. In this review, the categories of bone substitutes include allografts, ceramics, demineralized bone matrix, osteoinductive factors, autogenous platelet concentrate, mesenchymal stem cells, and gene therapy. Further, clinical studies have been evaluated by their levels of evidence in order to elucidate the precise effect of the bone substitute employed and to establish clinical guidance. This article will review both clinical studies based on evidence and basic research in current advances in order to avoid as far as possible any chances of failure in the future and to understand cellular biology in novel technologies.

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.

Diagnosing cervical fusion: a comprehensive literature review

Study Design

Comprehensive literature review.

Purpose

To document the criteria for fusion utilized in these studies to determine if a consensus on the definition of a solid fusion exists.

Overview of Literature

Numerous studies have reported on fusion rates following anterior cervical arthrodesis. There is a wide discrepancy in the fusion rates in these studies. While factors such as graft type, Instrumentation, and technique play a factor in fusion rate, another reason for the difference may be a result of differences in the definition of fusion following anterior cervical spine surgery.

Methods

A comprehensive English Medline literature review from 1966 to 2004 using the key words "anterior," "cervical," and "fusion" was performed. We divided these into two groups: newer studies done between 2000 and 2004, and earlier studies done between 1966 and 2000. These articles were then analyzed for the number of patients, follow-up period, graft type, and levels fused. Moreover, all of the articles were examined for their definition of fusion along with their fusion rate.

Results

In the earlier studies from 1966 to 2000, there was no consensus for what constituted a solid fusion. Only fifteen percent of these studies employed the most stringent definition of a solid fusion which was the presence of bridging bone and the absence of motion on flexion and extension radiographs. On the other hand, the later studies (2000 to 2004) used such a definition a majority (63%) of the time, suggesting that a consensus opinion for the definition of fusion is beginning to form.

Conclusions

Our study suggests that over the past several years, a consensus definition of fusion is beginning to form. However, a large percentage of studies are still being published without using stringent fusion criteria. To that end, we recommend that all studies reporting on fusion rates use the most stringent criteria for solid fusion following anterior cervical spine surgery: the absence of motion on flexion/extension views and presence of bridging trabeculae on lateral x-rays. We believe that a universal adoption of such uniform criteria will help to standardize such studies and make it more possible to compare one study with another.

Long term outcome of anterior cervical discectomy and fusion using coral grafts

BACKGROUND

To determine the long term efficacy of coral grafts in anterior cervical discectomy and fusion.

METHODS

In this prospective longitudinal study, All patients presenting with myelopathy and/or radiculopathy due to discal hernia or cervical spondylosis underwent anterior cervical microdiscectomy, arthrodesis with coral, and stabilization with anterior cervical locking plates. Clinical and radiological post-operative evaluations were performed at 2 days, 3, 6, and 12 months, and then yearly. The visual analogue scale was used for the evaluation of pain. Fusion was defined as the absence of motion on dynamic imaging combined with the disappearance of radio-lucent lines around the graft. The mean follow-up period was 44 months. In 83.3%, 91.2% and 93.7% of patients there was a satisfactory outcome for neck pain, arm pain, and motor deficit, respectively. The overall complication rate was 17.5%, all of which were transient. Additional surgery was required in nine cases. The occurrence of complications is correlated with less satisfactory outcomes for both neck and arm pain. While 95.5% of patients expressed overall satisfaction with their surgery, 70.5% stated that they had returned to their previous activities. The fusion rate was 45%; which was not correlated with clinical outcome and more likely in patients with of cervical spondylosis and one-level arthrodesis.

CONCLUSIONS

Despite satisfactory clinical results and a long follow-up period, coral implants yield low fusion rates, particularly in patients with discal hernia of two-level arthrodesis. The use of coral grafts cannot be recommended when fusion is one of the post-operative endpoints.

Hydroxyapatite-bioactive glass ceramic composite as stand-alone graft substitute for posterolateral fusion of lumbar spine: a prospective, matched, and controlled study

STUDY DESIGN

Prospective, matched, and controlled study.

OBJECTIVE

To evaluate the efficacy of hydroxyapatite-bioactive glass ceramic composite (Chitra-HABg) as a stand-alone graft substitute in promoting posterolateral fusion in the lumbar spine as compared with autologous bone.

BACKGROUND

The use of ceramics as stand-alone graft substitutes in posterolateral fusion remains controversial. The Chitra-HABg is a new composite that has undergone clinical trials in various orthopedic applications with excellent clinical and radiologic outcomes.

METHODS

Twenty-four patients underwent instrumented posterolateral fusion, with Chitra-HABg laid on the left intertransverse bed and autogenous graft on the right side. The primary outcome measure was radiologic consolidation of the graft, and secondary outcome measures were the work status and the Modified Oswestry Disability index. The McNamara and Student chi test were applied for statistical analysis.

RESULTS

Although the study was prematurely terminated owing to the high incidence of resorption of Chitra-HABg, 22 of the 24 subjects were followed-up for a minimum of 1 year. At the end of 1-year, excellent radiologic outcome was seen on the right side (autogenous graft) in all the cases, whereas 95% (21/22) of the cases had poor consolidation on the left side (Chitra-HABg). The clinical outcome was rated as good in 16/22 (73%) patients, fair in 5, and poor in only 1 patient, but this had no statistically significant association with the consolidation of the fusion mass.

CONCLUSIONS

This study clearly demonstrates that hydroxyapatite-bioactive glass ceramic composites (Chitra-HABg) has no role as stand-alone bone graft substitutes in posterolateral fusion of the lumbar spine, as the composite undergoes resorption without the formation of bridging callus.

LEVEL OF EVIDENCE

Level 1.

[Experience with Poly Ether Ether Ketone (PEEK) cages and locking plate for anterior cervical fusion in the treatment of spine trauma without cord injury]

PURPOSE OF THE STUDY

The purpose of this study was to determine whether spinal fusion using radiotransparent cages can be an appropriate treatment for traumatic injury of the cervical spine.

MATERIAL AND METHODS

This series included 30 patients aged 17-84 years (average 46 years) treated between October 1999 and June 2003 for traumatic injury of the cervical spine without neurological deficit or cord injury. There were two bifocal cases so that the study concerned 32 fusions. Injuries were: tear drop (n=1), serious flexion sprain (n=8), biarticular dislocation (n=4), serous hyperextension sprain (n=4), dislocation-fracture (n=1), uniarticular fracture (n=7), fracture-separation of the facet joints (n=4), post-traumatic herniation (n=3). For each injury, we measured pre and postoperatively and at last follow-up: the intersomatic angle, anterior displacement, and height of the intersomatic space at the center of the intervertebral disc. All x-rays were read twice, by two independent investigators. In the event of disagreement, the x-rays were read again by a senior surgeon and the main author of this article. Anterior fusion was achieved using a Poly Ether Ether Ketone (PEEK) (32%) and knitted carbon (68%) cage (cologne, Ostapek, Nexis) filled with cancellous bone harvested percutaneously from the iliac crest. The cage was associated with an anterior titanium plate fixation (Senegas, Euros and Orion, Medtronic). A posterior approach was associated if further stability was required (n=4 fusions). All patients were reviewed at minimum five months follow-up. Intersomatic fusion was verified on the standard x-rays (plus stress images and computed tomography at three months). Fusion was considered to be achieved if continuous bone lines crossed the graft and angle measurements remained stable, with the cage in the same position on successive examinations.

RESULTS

One patient died from lung cancer five months after spinal fusion. All other patients survived with a mean follow-up of 24 months. Fusion was achieved in all cases, at mean 78 days. The mean intersomatic angle increased from 12 degrees kyposis preoperatively to 13 degrees lordosis postoperatively at last follow-up. Anterior displacement of the fractured vertebral body was 3 mm preoperatively and 0.3 mm postoperatively. Height in the middle of the intersomatic space was 5.3 mm preoperatively and 8.2 mm postoperatively. There were no cases of secondary displacement.

DISCUSSION

This study demonstrated that fusion with an intersomatic cage associated with anterior plating can be used in spine trauma victims, providing an outcome as good as in patients with degenerative disease. This method enables nearly anatomic reduction without secondary displacement and fusion in a short delay (which can be explained by the mechanical properties of the assembly and by the use of pure cancellous graft from the iliac crest). There is very little morbidity in our experience. For us, this technique is more reliable than fusion using a tri-cortical iliac crest graft.

CONCLUSION

The use of an intersomatic cage is a simple, reliable technique for intersomatic spinal fusion with little morbidity for unstable traumatic injury of the spine without spinal cord injury.

Evaluation of hydroxyapatite ceramic vertebral spacers with different porosities and their binding capability to the vertebral body: an experimental study in sheep

Object

The aim of this study was to evaluate the degree of bone ingrowth and bonding stiffness at the surface of hydroxyapatite ceramic (HAC) spacers with different porosities in an animal model and to discuss the ideal porous characteristics of these spacers for anterior spinal reconstruction.

Methods

Twenty-one adult sheep (age 1–2 years, mean weight 70 kg) were used in this experiment. Surgery consisted of anterior lumbar interbody fusion at L2–3 and L4–5, insertion of an HAC spacer (10 × 13 × 24 mm) with three different porosities (0, 3, and 15%), and single-rod anterior instrumentation. At 4 and 6 months postoperatively, the lumbar spines were harvested. Bonding conditions at the bone–HAC spacer interface were evaluated using neuroimages and biomechanically. A histological evaluation was also conducted to examine the state of bone ingrowth at the surface of the HAC spacer.

Biomechanical testing showed that the bonding strength of HAC at 6 months postoperatively was 0.047 MPa in 0% porosity spacers, 0.39 MPa in 3%, and 0.49 MPa in 15% porosity spacers. The histological study showed that there was a soft-tissue layer at the surface of the HAC spacer with 0% porosity. Direct bonding was observed between bone and spacers with 3 or 15% porosity. Micro–computed tomography scans showed direct bonding between the bone and HAC with 3 or 15% porosity. No direct bonding was observed in HAC with 0% porosity.

Conclusions

Dense (0%) HAC anterior vertebral spacers did not achieve direct bonding to the bone in the sheep model. The HAC vertebral spacers with 3 or 15% porosity showed proof of direct bonding to the bone at 6 months postoperatively. The higher porosity HAC spacer showed better bonding stiffness to the bone.

Instrumented fusion of thoracolumbar fracture with type I mineralized collagen matrix combined with autogenous bone marrow as a bone graft substitute: a four-case report

In order to avoid the morbidity from autogenous bone harvesting, bone graft substitutes are being used more frequently in spinal surgery. There is indirect radiological evidence that bone graft substitutes are efficacious in humans. The purpose of this four-case study was to visually, manually, and histologically assess the quality of a fusion mass produced by a collagen hydroxyapatite scaffold impregnated with autologous bone marrow aspirate for posterolateral fusion. Four patients sustained an acute thoracolumbar fracture and were treated by short posterior segment fusion using the AO fixateur interne. Autologous bone marrow (iliac crest) impregnated hydroxyapatite-collagen scaffold was laid on the decorticated posterior elements. Routine implant removal was performed after a mean of 15.3 months (12–20). During this second surgery, fusion mass was assessed visually and manually. A bone biopsy was sent for histological analysis of all four cases. Fusion was confirmed in all four patients intraoperatively and sagittal stress testing confirmed mechanical adequacy of the fusion mass. Three out of the four (cases 2–4) had their implants removed between 12 and 15 months after the index surgery. All their histological cuts showed evidence of newly formed bone and presence of active membranous and/or enchondral ossification foci. The last patient (case 1) underwent implant removal at 20 months and his histological cuts showed mature bone, but no active ossification foci. This four-case report suggests that the fusion mass produced by a mineralized collagen matrix graft soaked in aspirated bone marrow is histologically and mechanically adequate in a thoracolumbar fracture model. A larger patient series and/or randomized controlled studies are warranted to confirm these initial results.

Efficacy and safety of the use of titanium mesh cages and anterior cervical plates for interbody fusion after anterior cervical corpectomy

BACKGROUND

To determine the safety and effectiveness of the use of titanium mesh cages (TMCs) and anterior cervical plates (ACPs) for interbody fusion after anterior cervical corpectomy.

METHODS

From June 2001 to June 2003, 15 patients underwent reconstruction with TMCs and ACPs for interbody fusion after anterior cervical corpectomy in our hospital. The mean follow-up is 13.6 months (range, 9-24 months). Subjects included those with cervical degenerative, traumatic, or pathological diseases. Titanium mesh cages were filled with autologous bone grafts taken from the corpectomy and iliac crest bone chips and were all filled with triosite (calcium phosphate ceramics). The patients' observable signs, neurological reconstruction results, and complications were fully and explicitly recorded throughout the procedure. Radiological imaging studies for measurements of coronal and sagittal angles, sagittal displacements, and settling ratio changes were performed to evaluate spinal stability. We used axial cervical computed tomography (CT) and reconstructive sagittal cervical CT to demonstrate interbody fusion within titanium mesh.

RESULTS

The alleviation and frequent disappearance of the subjects' original symptoms and the significant neurological recovery obvious in most patients indicated that postoperative spinal stability could be well maintained. No significant differences in mean cage height-related settling rates, mean sagittal displacements, and mean coronal and sagittal angle changes were observed between 1-level and multilevel corpectomy. All patients who received axial and reconstructive sagittal cervical CT scan could demonstrate true interbody fusion within TMC, and no nonunions were present. Cage malplacement was observed in one subject who had neck pain and neck stiffness, rather than from radiculopathy or myelopathy. One subject died of acute myocardial infarction. There were no ceramic-related complications.

CONCLUSIONS

Based on preliminary findings from this study, reconstruction involving TMC interbody fusion with ACP fixation after anterior cervical corpectomy serves as an effective and safe method for the treatment of cervical disease.

Implantation of an empty carbon fiber cage or a tricortical iliac crest autograft after cervical discectomy for single-level disc herniation: a prospective comparative study

Object

The authors conducted a study to evaluate and compare prospectively the implantation of either an empty carbon fiber composite frame cage (CFCFC) or an iliac crest autograft after anterior cervical discectomy (ACD) for cervical disc herniation with monoradiculopathy.

Methods

Thirty-six consecutive patients with one-level radiculopathy due to single-level cervical disc herniation were treated by ACD, and implantation of either an empty CFCFC (24 patients) or an iliac crest autograft (12 patients). Radiological and clinical assessments were performed preoperatively, immediately postoperatively; and at 3, 6, and 12 months postoperatively. Fusion, at the 12-month follow-up examination was demonstrated in 96% of the patients in the cage group and in 100% of those in the autograft group. The mean anterior intervertebral body height was 3.7 mm preoperatively and 3.9 mm at 12 months in the CFCFC, and 4.1 and 3.8 mm, respectively, in the autograft group. In cage-treated patients, neck pain, as measured using the visual analog scale (VAS) (Score 0 = minimum; 10 = maximum) decreased from 6.4 preoperatively to 2.0 at 12 months, and radicular pain, decreased from 8.4 preoperatively to 1.5 at 12 months. In the autograft group, neck pain changed from a mean preoperative VAS score of 7.2 to 2.5 at 12 months, and radicular pain decreased from a preoperative mean of 7.8 to 1.4 at 12 months. Analysis of the 12-Item Short Form Health Survey domains and the Oswestry Disability Index scores indicated a significant improvement in both the Physical and Mental Component Summary domains in both groups.

Conclusions

Implantation of an empty CFCFC or a tricortical iliac crest autograft after ACD are safe and reliable options for the treatment of cervical disc herniation causing one-sided radiculopathy. Both procedures produced equally satisfying clinical and radiological results, leading to a high fusion rate and maintaining intervertebral height. Implantation of an empty CFCFC has the advantages of avoiding any donor site morbidity and requiring a significantly shorter operative time.

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

Few histological studies on bone substitutes in human cervical spine are available and the biological processes of bone substitutes are not well documented. The authors studied four failure cases of cervical interbody fusion: two cases with hydroxyapatite (HA), one case with beta-tricalcium phosphate ceramic (beta-TCP) and one case with xenograft (bovine bone). Clinical data showed that all the patients experienced neck pain with or without numbness of upper extremity due to fusion failure. Successful fusions were achieved after the salvage surgeries in which autograft were used. Radiographs showed that radiolucent lines were present in all cases. Two HA substitutes fractured without complications. One of them sank into the vertebral body. Some small beta-TCP fragments were found under the microscope. Histological study demonstrated only a few newly formed bones at the interface of the substitutes. The fragments of HA were encapsulated by fibrous tissue. The degradation process and bone regeneration were more active in beta-TCP than in HA. The intertrabecular spaces of bovine bone were filled with fibrous tissue. The results suggest that a porous calcium phosphate ceramic with special design might assure bone ingrowth and meet the mechanical requirements in cervical interbody fusion. The complications of these materials in the cervical spine should be highlighted.

A prospective randomized comparison of rectangular titanium cage fusion and iliac crest autograft fusion in patients undergoing anterior cervical discectomy

Object

The authors compare clinical outcome and fusion rates after iliac crest autograft (ICAG)– and rectangular titanium cage (RTC)–augmented fusion in patients undergoing anterior cervical discectomy (ACD).

Methods

One hundred consecutive patients with 127 levels of cervical disc disease refractory to conservative treatment were randomized into one of the two treatment groups (ICAG/RTC fusion). The visual analog scale was used by the patient to rate overall pain and head, neck, arm, and donor site pain separately. Myelopathy was documented according to Japanese Orthopaedic Association and Nurick grading systems. Outcome was analyzed using Odom criteria, the 36-Item Short Form (SF-36), and Patient Satisfaction Index scales. Fusion rates were assessed on standard and flexion–extension radiographs. Follow-up data of at least 12 months' duration were available for 95 patients.

More residual overall pain after 12 months was documented in patients who underwent ICAG fusion (3.3 ± 2.5 [ICAG] and 2.2 ± 2.4 [RTC]; p < 0.05). Although arm and head pain were minimal in both groups, neck pain proved to be the predominant symptom (2.7 ± 2.5 [ICAG] and 1.9 ± 2.1 [RTC]), which resolved in only 67 and 48% of RTC-and ICAG-treated patients, respectively (p < 0.05). Myelopathy improved comparably in both groups. Regardless of increased pain in ICAG-treated patients, PSI and SF-36 scores were not significantly different between groups (only four [8%] of 47 ICAG-treated patients and five [10%] of 48 RTC-treated patients were unsatisfied). Good to excellent functional recovery according to Odom criteria was observed in 75 and 79% of ICAG- and RTC-treated patients, respectively. Fusion rates were 81 and 74%, respectively (p = 0.51).

Conclusions

Fusion rates and clinical outcome at 12 months after ACD were comparable between patients who underwent ICAG and RTC fusion. The use of rectangular cages, however, avoids donor site morbidity and reduces overall pain and, thus, seems to be an advantageous treatment alternative.

Primary stability of anterior lumbar stabilization: interdependence of implant type and endplate retention or removal

This is a comparative in vitro biomechanical study of the primary stability of an anterior lumbar interbody stabilization. The objective was to compare the stability of a interbody stabilizing titanium cage with and without the retention of the bordering vertebral endplates, as well as to compare the titanium cage with a tricalcium phosphate block when the endplates are removed. An adequate blood supply is critical for interbody fusion, which suggests surgical treatment of the bordering endplates. On the other hand, primary stability is improved by the retention of the endplates. Furthermore, bone substitute materials are finding more frequent use due to complications associated with autologous bone grafts. Ten bovine lumbar spine motion segments (average age 6 months) were investigated. Pure bending loadings as well as eccentric axial compression loadings were applied. A titanium cage and tricalcium phosphate block, were tested in conjunction with an anterior augmentation (MACS). Range of motion, neutral zone (NZ) and bending stiffness were measured under pure bending to 10 Nm, and bending stiffness under axial loads of up to 1,500 N. Range of motion of both implants in flexion-extension was significantly smaller than physiologic (cage without endplates 4.3 degrees , cage with 2.8 degrees , block without 3.4 degrees , and physiologic 6.6 degrees , all p<0.001). The cage with endplates and the block without endplates were both significantly stiffer than physiologic in all directions except left lateral bending. The block without endplates and the cage with endplates were both stiffer than the cage without endplates. The results suggest that the use of the bone substitute block provides better stability than the cage when the endplates are removed.

Outcome Analyses of Interbody Titanium Cage Fusion Used in the Anterior Discectomy for Cervical Degenerative Disc Disease

Anterior discectomy and fusion to treat cervical degenerative disc disease is the preferred procedure for many spine surgeons. The ideal device for structural reconstruction of the anterior cervical spine remains controversial. The purpose of this prospective study was to investigate the effectiveness of a non-threaded titanium cage in performing anterior spinal fusion for cervical degenerative disc disease. The clinical and radiologic data of 78 consecutive patients were reviewed. Neurologic outcome was assessed using Odom's criteria. Neck pain was graded using a 10-point visual analog scale. The cervical spinal curvature, the height of foramina, and fusion status were evaluated on preoperative and postoperative radiographs. Mean follow-up was 24.9 (range 18-35) months. An excellent or good result was found in 92% of the patients with radiculopathy, 69% of those with myelopathy, and 73% of those with myeloradiculopathy. Statistical analyses also showed improvement of cervical pain after surgery (P < 0.001) and a significant increase in foraminal height (P = 0.035). Cervical kyphosis was present in 27 (34%) patients before surgery; it was corrected to lordosis in 9. The fusion rate at 12 months and 24 months was 91% and 95%, respectively. No surgery or cage-related complication occurred in these patients. Non-threaded interbody cage fusion in this study achieved a high fusion rate and had a good neurologic outcome. These results suggest that non-threaded cage fusion is a safe and effective method for anterior cervical discectomy.

Cage containing a biphasic calcium phosphate ceramic (Triosite) for the treatment of cervical spondylosis

BACKGROUND

We evaluated the fusion efficacy and clinical outcomes of a cage containing a biphasic calcium phosphate ceramic (Triosite) in treating cervical spondylosis.

METHODS

We randomly divided 100 patients with cervical spondylosis undergoing anterior discectomy with interbody polyetheretherketone (PEEK) fusion into 2 groups in the past 2 years: group A (n = 50), PEEK cage containing a biphasic calcium phosphate ceramic (Triosite), and group B (n = 50), PEEK cage containing an autogenous iliac bone graft. We compared the fusion rate, fusion time, spinal curvature, and neuroforamen size between the 2 groups. We also compared excess operation time, excess blood loss, hospital stay, complications, and neurological recovery status between the groups.

RESULTS

The fusion rates were 57%, 67%, 77%, 82%, 92%, and 100% in group A and 81%, 86%, 95%, 95% 100%, and 100% in group B in the first 6 postoperative months. The fusion rate in group A was significantly lower than that in group B in the first 5 months after the procedure (P < .05 and P < .01, respectively), but the fusion rate reached 100% in both groups by the sixth month. Within the first 6 months, as the fusion level increased, the fusion rates reduced and time to fusion was delayed in both groups. There were no donor site complications in group A. However, 3 patients (6%) from group B experienced complications (1, wound infection; 1, numbness of thigh; and 1, subcutaneous hematoma) (P < .001). The hospital stay was shorter in group A (4.43 +/- 2.36 days) than in group B (7.00 +/- 3.77 days) (P = .001). The mean excessive blood loss and excessive operative time for an iliac bone graft in group B were 15 +/- 5 mL and 10 +/- 6 minutes. There was no statistical significance in spinal curve correction, neuroforamen enlargement, and neurological recovery.

CONCLUSIONS

A cage containing a biphasic calcium phosphate ceramic resulted in complete fusion by the sixth postoperative month, although the fusion rate was lower than that in a cage containing an autograft during the first 5 months after the operation and the time to fusion was delayed. Using a cage containing a biphasic calcium phosphate ceramic leads to a shorter hospital stay, less blood loss, shorter operative time, and no donor site complications. It seemed to be a good substitute for cervical spondylotic fusion.

Advantages and disadvantages of nonfusion technology in spine surgery

Nonfusion technology in spine surgery may improve outcomes by reducing surgical morbidity and the incidence of adjacent level degeneration; however, new technologies also introduce new short- and long-term complications. There is currently no evidence that nonfusion implants are superior to fusion in mid- to long-term follow-up. Understanding the potential risks and benefits of nonfusion technology is essential for spine surgeons and their patients. This article reviews the current evidence relating to the potential risks and benefits of nonfusion technology in spine surgery.

[Interest of porous biomaterials in spinal surgery]

PURPOSE OF THE STUDY

The aim of this work was to study the behavior of porous alumina ceramic cages in spinal cervical surgery, with or without plate fixation as needed.

MATERIAL AND METHODS

The population included 61 patients who underwent spinal surgery between May 1999 and October 2003. There were 48 women and 13 men, mean age 49 years at surgery. 74 implants were used, among them 71 were interbody cages. Ten patients were operated at two levels; C5-C6 and C6-C7 were most frequently instrumented. Patients were reviewed at 1 month, 3 months and 6 months, and, whenever possible more after. Clinical and radiological data were available for all patients.

RESULTS

Mean follow-up was 7.2 months. Postoperative clinical data included assessment of neck and arm pain, using a visual analogic scale and fusion status determined by the presence of trabecular bridging bone and the disappearance of lucent lines around the implant on plain anteroposterior and lateral cervical radiographs. Two patients required another intervention, allowing intra-operative assessment of the quality of fusion. Clinical results were in agreement with the usual outcome reported in the literature with 54% of patients free of postoperative neck or arm pain and restriction of function mild or absent in 88%. Bone healing was achieved at 6 months on the average in 58 cases and in all patients at 12 months, including the two patients who required revision.

DISCUSSION

The porous alumine cage is a reliable biocompatible and mechanically stable element helpful for achieving bone healing. Integration into bone tissue was radiographically satisfactory. This kind of implant appears to be an attractive alternative in spinal cervical surgery, avoiding donor graft site complications.

Use of osteopromotive growth factors, demineralized bone matrix, and ceramics to enhance spinal fusion

Recently developed materials that can enhance fusion rates for posterolateral lumbar arthrodesis may be used alone or in combination with autogenous bone grafts. Novel osteopromotive growth factor preparations are currently under scrutiny; these include autogenous growth factor concentrate, bovine bone-derived osteoinductive protein, and recombinant human MP52. Demineralized bone matrix products may enhance or extend grafts. However, few studies, especially prospective randomized clinical trials, have assessed their efficacy, so it is difficult to compare formulations. Ceramics have been evaluated in animal studies and human clinical trials for a variety of applications in spinal surgery. These materials function best as bone graft extenders or as bioactive osteoinductive material carriers in posterolateral lumbar fusions. They have the advantage of variable porosity, low cost, and ease of manufacture. Hydroxyapatite/tricalcium phosphate ceramics have been shown to perform as well as autogenous bone grafts but with fewer complications.

Three-level and four-level anterior cervical discectomies and titanium cage-augmented fusion with and without plate fixation

OBJECT

Cage-assisted anterior cervical discectomy and fusion (ACDF) has proven to be a safe and effective procedure for the treatment of one- and two-level degenerative disc disease (DDD). To the authors' knowledge, clinical results after three- and four-level interbody cage-augmented ACDF have not been reported in the literature. The authors investigated the safety and effectiveness of titanium cages used in such procedures and evaluated the results in cases with or without plate fixation.

METHODS

Fifty-six patients suffering from cervical DDD were divided into two groups. Group 1 included 32 patients who underwent titanium cage-assisted ACDF; Group 2 included 24 patients who underwent the same procedure, supplemented with plate fixation. The cervical DDD was confirmed by radiography and magnetic resonance imaging. The patients underwent radiographic evaluation to assess cervical lordosis, segmental height of cervical spine, the height of the foramina, and spinal stability. Neurological outcomes were assessed using the Japanese Orthopaedic Association (JOA) scores. Neck pain was graded using a 10-point visual analog scale (VAS). The follow-up period ranged from 13 to 28 months (mean 17.2 months). In both Groups 1 and 2 significant increase (p < 0.001) was demonstrated in the JOA scores (preoperatively 10.7 +/- 2.4 and 11.1 +/- 2, postoperatively 13.9 +/- 2.2 and 14.1 +/- 2.3, respectively) and VAS pain scores (preoperatively 8.8 +/- 0.9 and 8.5 +/- 1, postoperatively 3.1 +/- 2.1 and 2.8 +/- 1.8, respectively); however, there was no significant intergroup difference. A significant increase in the cervical lordosis, foraminal height, and segmental height was observed in both groups. Good stability of cage fusion was obtained in both groups 12 months postoperatively (90.6% in Group 1 and 91.7% in Group 2); however, there were no statistically significant intergroup differences. The complication rate in Group 2 was higher than that in Group 1. The hospital length of stay in Group 1 was significantly lower than in Group 2 (p < 0.001).

CONCLUSIONS

Analysis of these findings demonstrated that titanium cage-assisted ACDF provided long-term stabilization, increased lordosis, increased segmental height, and increased foraminal height. In both groups good neurological outcomes were achieved and donor site morbidity was avoided. The lower complication rate and shorter hospital stay, however, make the cage-assisted fusion without plate fixation better than with plate fixation.

Anterior cervical discectomy and fusion with implantable titanium cage: initial impressions, patient outcomes and comparison to fusion with allograft

BACKGROUND CONTEXT

The use of metal cage prosthetic devices in anterior cervical discectomy with fusion (ACDF) has increased rapidly. One of these devices is the titanium Rabea cage (Signus, Alzenau, Germany) [correction]. There are no peer-reviewed objective reports on the use of these cages in cervical discectomy.

PURPOSE

The authors present preliminary outcomes data on the Rabea cage. This study is intended to provide adjunct data for surgeons who are using or are considering the use of these devices.

STUDY DESIGN/SETTING

Patients in a private practice were studied prospectively as part of a long-term assessment of outcomes using several surgical procedures. Data were collated and analyzed by an independent researcher.

PATIENT SAMPLE

Rabea cages were used in consecutive candidates (n=37) for ACDF. The results using Rabea cages were compared with two prospectively studied control groups, one historical (n=66) and one concurrent (n=28), both groups using ACDF with bone allograft and no instrumentation.

OUTCOME MEASURES

Success at 6 months after surgery was determined using six major patient-reported outcome measures, including visual analog scales (VAS) for arm and neck pain, the Oswestry pain and disability scale, four-part (excellent-through-poor) scales for measurement of return to activities of daily living or to work and satisfaction with the results of surgery. Perioperative complications, number of vertebral levels fused, and worker's compensation and smoking status were also compared among the study groups. Fusion and subsidence were evaluated for the Rabea cage group.

METHODS

Criteria for inclusion consisted of consecutive patients who presented with unremitting radicular arm pain, with or without neck pain, and/or a neurological deficit that correlated with appropriate level and side neural compression on magnetic resonance imaging or computed tomography. Questionnaire follow-up was at 6 months after surgery with 100% compliance.

RESULTS

A total of 50 cages were implanted in the 37 patients. At 6-month follow-up, 78% of patients reported successful arm pain relief (VAS scores below 5). Patient satisfaction was successful in 78% of the cases. Other success rates included neck pain relief in 73% and Oswestry pain and disability scale in 70%. There was a median improvement in the Oswestry scores of 28 points (61% change). Worker's compensation patients fared dramatically worse than did the noncompensation patients in all outcome measurements. Combining all three study groups resulted in significantly worse outcomes for multilevel than for single-level procedures and for smokers compared with nonsmokers, but low case numbers precluded conclusive analysis for the Rabea group alone. In the Rabea group there were two complications, neither cage related, whereas none were reported for the ACDF controls. Rabea group fusion rates were 84% at 3 months and 95% at 6 months, but the clinical relevance of this radiological evidence when metal prostheses are used is questionable. The outcomes results were clinically and statistically indistinguishable from those of our control groups and were similar to published studies using other titanium cages.

CONCLUSIONS

This is the first prospective, independently conducted report on Rabea cages. Results of the short-term (6 months) follow-up did not differ from outcomes results in our patients who have undergone ACDF with bone allograft. Although this is a preliminary assessment, the Rabea cage may represent an alternative to bone dowels and hip graft. As is the case for other allografts, artificial or bone, the main advantage is elimination of donor site complications, and the disadvantages include difficulty in radiographic assessment of fusion and potential for cage subsidence.

Pitfalls of Anterior Cervical Fusion Using Titanium Mesh and Local Autograft

Cervical fusion cages have been developed to provide an anterior structural support without harvesting tricortical iliac bone. Limited numbers of investigations have focused on pitfalls of anterior cervical fusion using cage implants. The objective of this study is to report clinical results and implant-related complications in anterior cervical fusion using titanium mesh and anterior plating. Twenty-four cases with anterior cervical fusion using a titanium mesh with local autograft and anterior plating were reviewed. One-level fusion was performed in 7 cases, and 17 patients underwent two-level fusion with corpectomy. The mean follow-up period was 27 months. Radiographic assessment included sagittal alignment, fusion status, and complications related to cage implants. Iliac bone graft harvesting was obviated in all the patients, whereas 15 patients required concomitant use of ceramic bone substitute. Sagittal alignment of the operative level was lordotic in 19 cases (79%) and neutral in 5 cases (21%) at the final follow-up. No late kyphotic collapse was observed. Twenty-three cases (96%) achieved a solid fusion, whereas the time to fusion was averaged 6.2 months. Cage subsidence frequently occurred in 42% of upper vertebrae and 50% of lower vertebrae. The use of titanium mesh and local autograft for anterior cervical fusion obviated the need for harvesting iliac bone block and provided structural anterior column support. However, it required a longer period to achieve a solid fusion when compared with tricortical iliac autograft. Cage subsidence was frequently observed in the early postoperative period.