Anterior cervical fusion with interbody titanium cage containing surgical bone site graft: our institution's experience in 103 consecutive cases of degenerative spondylosis

Avulsion fracture of the anterior superior iliac crest following autograft for anterior lumbar fusion: case report and literature review

Avulsion fracture of the anterior superior iliac crest (ASIC) following autogenous bone grafting for anterior lumbar fusion (ALF) is an extremely rare complication. We describe a very rare case of avulsion fracture of the ASIC following autograft for ALF in a revision surgery for treating lumbar tuberculosis. A 68-year-old woman with lumbar tuberculosis underwent posterior debridement and posterior iliac crest bone graft fusion; however, her lumbar tuberculosis recurred 9 months after surgery. She then underwent a lumbar revision surgery, including removal of the posterior instrumentation and debridement, followed by anterior L2 corpectomy, debridement, anterior left iliac crest bone graft fusion, and internal fixation. When walking for the first time on postoperative day 3, she experienced a sharp, sudden-onset pain in the anterior iliac crest harvest area. X-ray revealed an avulsion fracture of the ASIC. Considering her failure to respond to conservative treatment for one week and large displacement of the fracture ends, an open reduction and internal fixation surgery was scheduled. Her pain symptoms were significantly relieved after the operation. Although rare, fracture of the ASIC following autograft for ALF should not be ignored. Fracture of the ASIC is usually treated conservatively. Additional surgical treatment is required only when intractable pain fails to respond to conservative treatment or when there is a large displacement of fracture ends that are not expected to heal spontaneously.

Implantation of an empty polyetheretherketone cage in anterior cervical discectomy and fusion: a prospective randomised controlled study with 2 years follow-up

PURPOSE

To compare the clinical outcomes, radiographic results and fusion rate of ACDF between empty PEEK cages and PEEK cages packed with β-tricalcium phosphate.

METHODS

Forty-five patients were prospectively enrolled with cervical degenerative disc disease who requiring ACDF with a PEEK cage. 23 patients were randomised to the study group (empty cages) and 22 patients were in the control group (cages filled with β-tricalcium phosphate). Both patient groups were fixed with a cervical locking plate. A CT scan was performed 12 months postoperatively and 24 months if not confirmed fused at 12 months to evaluate the status of fusion. Clinical status was evaluated using the Japanese Orthopaedic Association (JOA) score, the Oswestry Disability Index (ODI) and the Visual Analogue Scale (VAS).

RESULTS

46 levels (97.88%) in the study group and 44 levels (97.77%) in the control group were confirmed as fused at 24 months. There was no significant difference between the fusion rates observed in the study and control groups (p = 0.82). There was no significant difference in JOA, ODI, or VAS scores at 24 months follow-up. The results showed that the members of the non-fusion group tended to be older than the individuals in the fusion group at 12 months, but was not significant in statistics.

CONCLUSIONS

Similar fusion rates and clinical outcomes were achieved when using ACDF with PEEK cages and instrumentation, regardless of whether the cage was filled with bone substitute at 24 months follow-up. Fusion rates improved over time and are comparable between both groups. These slides can be retrieved under Electronic Supplementary material.

Titanium cages versus autogenous iliac crest bone grafts in anterior cervical discectomy and fusion treatment of patients with cervical degenerative diseases: a systematic review and meta-analysis

OBJECTIVE

A systematic review and partial meta-analysis is conducted to compare the efficacy and safety of anterior cervical decompression and fusion procedures employing either rectangular titanium cages or iliac crest autografts in patients suffering from cervical degenerative disc diseases.

METHODS

Medline, PubMed, CENTRAL, and Google Scholar databases were searched up to June 2015, using the key words cervical discectomy; bone transplantation; titanium cages; and iliac crest autografts. Outcomes of interbody fusion rates were compared using odds ratios (ORs) with 95% confidence intervals (CIs). Values of the Japanese Orthopaedic Association score, and visual analog scale before and after operation were also compared.

RESULTS

The rate of interbody fusion was similar between patients in the iliac crest autograft and titanium cage groups (pooled OR = 0.33, 95% CI = 0.07 to 1.66, P = .178). The overall analysis showed that patients in the two groups did not have significantly different post-surgery Japanese Orthopaedic Association score (pooled difference in means = -0.05, 95% CI = 0.73 to 0.63, P = .876). Improvement in arm and neck pain scores were assessed with a visual analog scale and differed significantly between patients in the iliac crest autograft and titanium cage groups (pooled difference in means = 0.16, 95% CI = -0.44 to 0.76, P = .610; and pooled difference in means = -0.44, 95% CI = -2.23 to 1.36, P = .634, respectively).

CONCLUSIONS

Our results suggest that the use of titanium cages constitutes a safe and efficient alternative to iliac crest bone autografts for anterior cervical discectomy with fusion.

Analysis of clinically relevant mechanical and thermal characteristics of titanium foam spinal implants during drilling

Although high biocompatibility promotes the use of titanium (Ti) alloy in spinal implants, this material shows high stiffness, which is an issue for removal by drilling. The recently developed, porous Ti foam implants, which have shown enhanced osteoformation, may overcome this flaw. Thus, this study aimed to compare the mechanical and thermal characteristics of Ti-foam (80 % porosity) and conventional Ti alloy (0 % porosity) implants drilled in clinically relevant conditions. Mechanical properties were analyzed by measuring axial and torque forces using a pressure sensor with a drill of 2.5-mm diameter at a rotation frequency of 20 Hz. Thermography was used to evaluate the heat generated by a diamond burr attached to a high-speed (80,000 rpm) drill. The torque and axial strengths of Ti foam (13.63 ± 1.43 and 82.60 ± 7.78 N, respectively) were significantly lower (P = 0.001) than those of Ti alloy (73.58 ± 13.60 and 850.72 ± 146.99 N, respectively). Furthermore, irrigation reduced the area of local heating for Ti foam to 56-82 % of that for Ti alloy, indicating lower thermal conductivity. These data suggest that the use of Ti foam implants may be advantageous in cases with a probability of implant drilling in the future.

Anterior cervical discectomy and fusion with "mini-invasive" harvesting of iliac crest graft versus polyetheretherketone (PEEK) cages: a retrospective outcome analysis

BACKGROUND

Limited outcome data suggested a minimal evidence for better clinical and radiographic outcome of polyetheretherketone cages compared with bone grafts in the anterior cervical discectomy and fusion. We proposed a "mini-invasive" surgical technique for harvesting iliac crest grafts that provides bicortical autografts of sufficient size to be used in multilevel cervical procedures and is not associated with long-term significant donor site pain.

METHODS

All patients undergoing discectomy and fusion during a three years period were consecutively extracted from computer database and retrospectively evaluated by means of telephonic interview, independently from surgical procedure (iliac crest autograph or prosthesis). Two procedure-blinded neurologists retrieved baseline clinical-demographic data and pre-surgical scores of routinely performed scales for pain and functional abilities. Afterwards, a third blinded neurologist performed clinical follow up by a semi-structured interview including Verbal Analog Scale for pain and Neck Disability Scale for discomfort.

RESULTS

80 patients out of 115 selected cases completed the follow up. 40 patients had been treated by mini-invasive bone graft harvesting and 40 with PEEK cages for cervical fusion. VAS for both neck and arm pain were significantly reduced within groups. Patients did not complaint any significant pain and/or paraesthesias at donor site from the first week after intervention. Neck Disability Scale was significantly lower at the end of follow up in both groups.

CONCLUSIONS

"Miniinvasive" bicortical autografts is a less invasive, inexpensive technique to harvest iliac graft that may produce a reduced amount of general and local donor-site complications without outcome differences with prosthetic cages.

Histological, mechanical, and radiological study of osteoformation in titanium foam implants

BACKGROUND

Titanium (Ti) is widely used for implants because of its high mechanical reliability and because it aids osteoformation. However, it also produces artifacts during radiological imaging. Further, Ti implants can sometimes cause the surrounding bone to break. Owing to recent advances, Ti can be transformed into sponge-like, porous materials having a three-dimensional network of pores; such materials are called Ti foams. These foams exhibit distinct characteristics that make them more suitable than nonporous Ti. The objective of this study was to evaluate Ti foams as implant materials.

METHODS

Implants based on Ti foams having porosities of 80% and 90% were embedded in the femurs of 11 rabbits. Implants based on 0% porosity Ti were used as controls. Five rabbits were sacrificed 4 weeks after implantation, while the remaining were sacrificed after 12 weeks. The femurs containing the Ti implants were harvested and analyzed.

RESULTS

Biomechanical analyses showed that the 80% porosity implants induced greater osteoformation. There were significant differences in the average pushout strengths of the control and 80% porosity implants after 4 weeks (p = 0.048) and 12 weeks (p = 0.001). Histopathological analyses confirmed osteoformation in the case of the 80% porosity implants. Analyses of the micro-computed tomography images of the Ti foam-based implants did not suggest the presence of artifacts.

CONCLUSIONS

The 80% porosity Ti implants did not exhibit the shortcomings associated with conventional Ti implants. In addition, they induced greater osteoformation. Finally, the Ti foams did not produce radiological artifacts.

Novel biodegradable lamina for lamina repair and reconstruction

BACKGROUND CONTEXT

Posterior laminectomy is an effective spinal surgical procedure. The adhesion of postoperative scar tissue to surgically exposed dura and, occasionally, to nerve roots can cause failed back surgery syndrome. The establishment of a barrier between scar tissue and dura that is made of hard material may prevent scar adhesions.

PURPOSE

To evaluate the efficacy of a novel biodegradable multi-amino acid copolymer/nanohydroxyapatite composite artificial lamina.

METHODS

A cervical laminectomy animal model in goats was used, and the animals were randomly divided into three groups. In the test group, cervical 4 was removed by laminectomy and the artificial lamina was inserted (n=12). In the control group, the incision was closed directly without implantation (n=9). The goats in the normal group did not undergo any procedure or treatment. Copolymer efficiency was tested by using X-ray, computed tomography scanning, magnetic resonance imaging, scanning electronic microscope, and histologic and biomechanical measurements 4, 12, and 24 weeks postoperation.

RESULTS

No shifting of the artificial lamina or dural adhesion pressure was observed. New cervical natural bone formed in the defect and the bony spinal canal was rebuilt. In the control group, fibrous scar tissue filled the defect and exerted pressure on the dura. No paralysis was observed, and gait was normal in all test and control goats.

CONCLUSIONS

Artificial lamina can prevent the epidural adhesions surrounding the defect and promote effectively bone tissue repair and new bone formation.

The CASCADE trial: effectiveness of ceramic versus PEEK cages for anterior cervical discectomy with interbody fusion; protocol of a blinded randomized controlled trial

Background

Anterior cervical discectomy with interbody fusion cages is considered the standard surgical procedure in patients with cervical disc herniation. However, PEEK or metal cages have some undesirable imaging characteristics, leading to a search for alternative materials not creating artifacts on images; silicon nitride ceramic. Whether patients treated with silicon nitride ceramic cages have similar functional outcome as patients treated with PEEK cages is not known. We present the design of the CASCADE trial on effectiveness of ceramic cages versus PEEK cages in patients with cervical disc herniation and/or osteophytes.

Methods/Design

Patients (age 18–75 years) with monoradicular symptoms in one or both arms lasting more than 8 weeks, due to disc herniation and/or osteophytes, are eligible for the trial. The study is designed as a randomized controlled equivalence trial in which patients are blinded to the type of cage for 1 year. The total follow-up period is 2 years. The primary outcome measure is improvement in the Neck and Disability Index (NDI). Secondary outcomes measures include improvement in arm pain and neck pain (VAS), SF-36 and patients' perceived recovery. The final elements of comparison are perioperative statistics including operating time, blood loss, length of hospital stay, and adverse events. Lateral plane films at each follow-up visit and CT scan (at 6 months) will be used to judge fusion and the incidence of subsidence. Based on a power of 90% and assuming 8% loss to follow-up, 100 patients will be randomized into the 2 groups. The first analysis will be conducted when all patients have 1 year of follow-up, and the groups will be followed for 1 additional year to judge stability of outcomes.

Discussion

While the new ceramic cage has received the CE Mark based on standard compliance and animal studies, a randomized comparative study with the golden standard product will provide more conclusive information for clinicians. Implementation of any new device should only be done after completion of randomized controlled effectiveness trials.

Non-fusion rates in anterior cervical discectomy and implantation of empty polyetheretherketone cages

STUDY DESIGN

A prospective analysis.

OBJECTIVE

Our aim was to assess the radiographically detectable bony fusion in patients with anterior cervical discectomy (ACD) and polyetheretherketone (PEEK)-cage implantation without additional filling. Furthermore, clinical data of patients with and without fusion were compared.

SUMMARY OF BACKGROUND DATA

PEEK-cage implantation is performed in cervical spinal surgery because of its benefits. However, fusion rates without filling of the cage have not been reported.

METHODS

Patients selected for ACD with PEEK-cage implantation prospectively underwent plain radiography in anterior-posterior and lateral projections during the postoperative hospital stay and at follow-up. Furthermore, clinical status was evaluated using the Odom scale, the Short Form-36, the Visual Analog Scale (VAS) for arm and neck pain, and the cervical Oswestry score. Fusion status, migration, and subsidence of the PEEK cage were evaluated on the basis of the lateral radiographs. Fusion was confirmed by presence of continuous trabecular bone bridges in the disc space. To exclude an influence of the cage on the evaluation of fusion rates, fusion was evaluated in analogous fashion retrospectively in a control group.

RESULTS

A total of 52 patients underwent ACD and interbody fusion. One-level surgery was performed in 44 patients and 2-level surgery in 8 patients. A total of 60 ACD and interbody fusions with a PEEK cage were analyzed. A majority of operations were at the C5/6 level (40 patients, 77%). Cage height was 4 mm in 32 cases, 5 mm in 23 cases, and 6 mm in 5 cases. Bony fusion was present at 43 treated levels (71.7%), whereas at 17 levels (28.3%) no fusion was found. Statistical analysis revealed no significant difference between the fusion and non-fusion groups regarding time to follow-up, implanted cage height. Short Form-36, cervical Oswestry score, VAS arm and neck, or Odom criteria. In the control group, ACD was performed in 29 patients (42 levels; 18 one-level and 12 two-level operations). Bony fusion was present at 30 levels (71.4%), whereas non-fusion was present at 12 treated levels (28.6%). Statistically analysis revealed no significant difference between the study group and the control group regarding time to follow-up or fusion rates.

CONCLUSION

Implantation of empty PEEK cages after ACD shows an unexpectedly low rate effusion according to radiologic criteria, although no statistically significant difference could be observed clinically.