Bone Graft Implants Research Articles

Interferon-γ enhances the efficacy of autogenous bone grafts by inhibiting postoperative bone resorption in rat calvarial defects

PurposeInterferon (IFN)-γ is a major cytokine produced by immune cells that plays diverse roles in modulating both the immune system and bone metabolism, but its role in autogenous bone grafting remains unknown. Here, we present that local IFN-γ administration improved the efficacy of autogenous bone graft treatment in an experimental rat model. MethodsAn autogenous bone graft model was prepared with critically sized rat calvariae defects. Four weeks (w) after bone graft implantation, rats were treated locally with IFN-γ or were not treated. The effect of IFN-γ on bone formation was evaluated for up to 8w with micro-computed tomography, quantitative histomorphometry, and Von Kossa staining. Osteoclastogenesis was assessed by tartrate-resistant acid phosphatase staining. Immunohistochemistry staining or quantitative polymerase chain reactions were used to estimate the expression of osteoclast differentiation factor and inflammatory cytokines including tumor necrosis factor (TNF)-α, a well-known stimulant of osteoclastogenesis and an inhibitor of osteoblast activity, in defects. ResultsNewly formed bone gradually replaced the autogenous bone grafts within 4w, although severe bone resorption with osteoclastogenesis and TNF-α expression occurred after 6w in the absence of IFN-γ administration. IFN-γ administration markedly attenuated bone loss, osteoclastogenesis, and TNF-α expression, while it enhanced bone formation at 8w. ConclusionLocal IFN-γ administration promoted bone formation in autogenous bone grafts possibly via regulating osteoclastogenesis and TNF-α expression. The data provide insights into the potential roles of IFN-γ in autogenous bone grafting.

Vascularized bone grafting fixed by biodegradable magnesium screw for treating osteonecrosis of the femoral head

Hip-preserving surgery with vascularized bone graft implantation has been widely practiced in treating osteonecrosis of the femoral head (ONFH). However, the current approach presents a drawback, in which the implanted bone graft without screw fixation may slip or exhibit a certain degree of displacement postoperatively. This study was designed to investigate the application potential of biodegradable magnesium (Mg) screws for the fixation of vascularized bone graft in ONFH patients. Forty-eight patients were randomly divided into two groups: the Mg screw group (vascularized bone grafting fixed by Mg screws) and the control group (vascularized bone grafting without fixation). During 12 month follow-up period after surgery, treatment outcomes in patients were assessed by multiple imaging techniques including x-ray and computed tomography (CT) scanning as well as functional recovery Harris hip score (HHS). The temporal changes in serum levels of Mg, Ca, and P as well as in vivo degradation rate of Mg screws were determined. The absence of potential adverse effects induced by degradation products from Mg screws on surrounding bone tissue was validated via CT imaging analysis. HHS was significantly improved in the Mg screw group when compared to the control group. X-ray imaging analysis showed that the screw shape did not show significant alteration due to the diameter of Mg screws measured with approximate 25% reduction within 12 months post-surgically. The postoperative serum levels of Ca, Mg, and P, which are relevant for liver and kidney function, were all within normal physiological range in all patients of both groups. The use of biodegradable Mg screws may provide a promising bone graft–screw fixation route in treating ONFH and present considerable potential for orthopedic applications.

Single-stage debridement and spinal fusion using PEEK cages through a posterior approach for eradication of lumbar pyogenic spondylodiscitis: a safe treatment strategy for a detrimental condition.

BackgroundPyogenic infections of the lumbar spine are a rare but critical pathology, yet with considerably high mortality rates. In cases indicating surgical therapy, the implantation of titanium cages or autologous bone grafts represent today's gold standard. Although non-metallic implants such as poly-ether-ether-ketone (PEEK) have proven to be advantageous in diverse degenerative conditions, their saftey and practicability in lumbar spine infection remains questionable. Moreover, the efficacy of a single-step radical debridement of the infected disc space with subsequent fusion from a strictly posterior approach continues to be an issue of debate. We therefore sought to evaluate the feasibility, clinical and radiological outcome of a single-step TLIF procedure using oblique PEEK cages in the surgical management of patients with lumbar pyogenic spondylodiscitis.MethodsFrom January 2009 through December 2013, all patients meeting the indication for surgical treatment of lumbar pyogenic spondylodiscitis were included. Patients demonstrating intact cortical bone on preoperative CT received a single-step radical debridement of the infected intervertebral disc space, posterior screw-and-rod instrumentation and implantation of an oblique PEEK cage using the TLIF technique. Oral antibiotics were continued for 12 weeks postoperatively and clinical and radiological results recorded throughout a minimum 1-year clinical follow-up.ResultsA total of 104 patients were admitted to receive surgical therapy for lumbar pyogenic spondylodiscitis. Within this patient population, 18 patients met the diagnostic criteria to receive the implantation of an oblique PEEK cage. Pathogens were detected in 13 cases with Staph. aureus being the predominant causative organism. All patients were discharged to recover in their domestic environment. Throughout the first year of clinical and radiological follow-up and beyond, none of the 18 patients demonstrated any signs of residual neurologic deficits or recurrent infection. Furthermore, two-plane conventional X-rays showed no significant implant subsidence or failure at any of the given time-points in up to 5 years postoperatively.ConclusionsIn patients meeting the criteria for surgical treatment of lumbar pyogenic spondylodiscitis, the implantation of PEEK cages using a single-step TLIF approach is a safe and feasible procedure. Based on our experience, the concern of a recurrent infection when implanting non-metallic cages may be refuted in carefully selected patients.

Initial Experience with Tricortical Iliac Crest Bone Graft and Human Amniotic Allograft in Evans Calcaneal Osteotomy

Background: Adult acquired flatfoot deformity is generally mediated with an Evans procedure where a wedge of bone is placed into the calcaneus to better align the foot and decrease the deformity. The purpose of this study was to assess the efficacy and safety of human amniotic allograft applied to allogeneic tri-cortical grafts in Evans calcaneal osteotomy. Methods: The medical records of patients who had Evans calcaneal osteotomy with implantation of tri-cortical iliac crest bone graft with human anmiotic allograft for surgical management of adult acquired flatfoot deformity with 2 years follow-up data were reviewed. Results: A total of 63 patients (mean age: 33.3 yr, range: 18 - 66 yr) were enrolled with adult acquired flatfoot deformity. Median time to weight-bearing was 6 weeks. Time to wearing normal shoes was 10 weeks, and time to radiographic healing was 16 weeks. Conclusions: The use of human amniotic allograft did not diminish the long term outcome of procedure or the short term benchmarks for healing after surgery. There were no nonunion, wound dehiscence, infection, or allergic or immune reaction reported. This retrospective study demonstrated that tri-cortical iliac crest bone graft and HAA could be safely used in Evans calcaneal osteotomy with favorable results.

Efficacy of Chitra granules (porous hydroxyapatite crystals) as an alloplastic bone graft

Introduction: Bone grafting is a gold standard technique in restoring the bone defects created due to the surgical removal of cysts and tumors as well as surgical corrections of skeletal deformities. The aim of the case series was to evaluate clinically, radiographically, and ultrastructurally the efficacy of Chitra granules, a porous hydroxyapatite synthetic bone graft, substituting as a restorative material in the maxillary bone defects. Materials and Methods: In this study, six patients were divided into two groups according to the size of the bone defect after the removal of periapical intraosseous lesions. Then, the defect was filled with Chitra granules mixed with sterile saline and the surgical site was closed as per regular surgical protocols. The surgical region was evaluated clinically and radiographically at regular intervals to assess healing and bone formation. Also, a bone biopsy was taken 3-6 months after implantation of bone graft for scanning electron microscopic study. Results: New bone formation with indistinct graft-surgical margin was evident in the postoperative radiographic evaluation after 6 months. Scanning electron microscopy revealed trabeculae of bone formation at the periphery and fibrous connective tissue growth in the pores of the granules along with ossification of fibrous connective tissue in and around the granules. Conclusion: In conclusion, with the encouraging results in the literature on the role of hydroxyapatite as an osseous filling material, Chitra granules as a biomaterial can be considered as a suitable alternative to autogenous grafts, allogenous grafts, and xenografts.

Cervical spondylodiscitis – A clinical analysis of surgically treated patients and review of the literature

ObjectiveThe aim of this study was to analyze our clinical and neurological results of surgically treated patients suffering from cervical spondylodiscitis with focusing particularly on the surgical methods used and to review the literature. Patients and methodsWe present a series of 21 patients operated with cervical spondylodiscitis between 1998 and 2011. Basic demographic data, comorbidities, the radiological segments involved, the surgical strategy with special consideration of the material used and the clinical outcome were evaluated retrospectively. ResultsThe mean age of 6 female and 12 male patients was 65 years (range 28–89 years). The mean follow-up was 3.7 years ranging between 4 weeks and 9 years. The leading symptom was neurological deficits rather than pain. The segments C 5/6 (n=8) and C 6/7 (n=7) were most frequently involved. Different surgical methods depending on the location, anatomical and pathological condition and extension of the lesion were performed. ConclusionIn conclusion, cervical spondylodiscitis could effectively be treated in the presented patient cohort by surgical decompression, debridement and PMMA or bone graft implants followed by long term antibiotic therapy. The presented surgical reconstruction technique with PMMA might be a feasible alternative to the use of bone graft or cages. The promising clinical results warrant future prospective studies to further investigate this technique.

Integration of fluoridated implants in onlay autogenous bone grafts – An experimental study in the rabbit tibia

IntroductionBone augmentation before treatment with endosseous implants is a common procedure for rehabilitation of the edentulous jaw. Both machined and surface modified implants have been used in one-stage and two-stage surgery protocols with varying results and survival rates. The influence of surface modification on the integration of implants has been documented in both non-grafted and grafted bone. The aim of this study was to compare the integration and stability of surface modified fluoridated vs. machined implants when placed simultaneously with an onlay bone graft. Material and methodsEight rabbits were used in this study. A disc shaped bone graft was harvested from each side of the sagittal suture of the calvarial bone and fixed bi-cortically to the proximal tibial metaphysis by means of a dental implant, 9 mm long and 3.5 mm in diameter with a smooth machined surface as control and a blasted, fluoridated surface as test. Test and control sides were randomised. After a healing time of 8 weeks, the rabbits were sacrificed and the implants were removed en block for light microscopic analysis. Bone to implant contact (BIC) was registered as well as the amount of bone filling a rectangle indicating a region of interest (ROI) in the grafted area. Resonance frequency analysis (RFA) was conducted both at the time of surgery and at the end of the study. ResultsOur results showed statistically significant differences in BIC within the grafted area and the total bone to implant contact between the test and control sides in favour of the surface modified implants. The bone area filling the threads within a region of interest showed no statistically significant difference between the test and control sides. RFA showed higher implant stability with significant differences at the time of sacrifice in favour of the fluoridated implants. ConclusionSurface modified fluoridated implants showed a higher degree of osseointegration and stability in onlay bone grafts compared with control implants with machined surface texture.

Polymeric scaffolds as stem cell carriers in bone repair

Although bone has a high potential to regenerate itself after damage and injury, the efficacious repair of large bone defects resulting from resection, trauma or non-union fractures still requires the implantation of bone grafts. Materials science, in conjunction with biotechnology, can satisfy these needs by developing artificial bones, synthetic substitutes and organ implants. In particular, recent advances in polymer science have provided several innovations, underlying the increasing importance of macromolecules in this field. To address the increasing need for improved bone substitutes, tissue engineering seeks to create synthetic, three-dimensional scaffolds made from polymeric materials, incorporating stem cells and growth factors, to induce new bone tissue formation. Polymeric materials have shown a great affinity for cell transplantation and differentiation and, moreover, their structure can be tuned in order to maintain an adequate mechanical resistance and contemporarily be fully bioresorbable. This review emphasizes recent progress in polymer science that allows relaible polymeric scaffolds to be synthesized for stem cell growth in bone regeneration.

The influence of porcine cathelicidins on neutrophils isolated from rabbits in the course of bone graft implantation

Antimicrobial peptides are important elements of host defence because of their direct antimicrobial activity and modulatory role in innate immune response. The purpose of the study was to determine whether porcine peptides PR-39, protegrins (PGs) and low molecular weight extract (LMWE) are able to influence the neutrophil response during bone graft implantation in rabbits. The study was conducted on 10 White New Zealand rabbits and neutrophil activity was assayed on the basis of elastase, myeloperoxidase, and alkaline phosphatase release as well as free radical generation. Our study showed that PR-39 and PGs inhibited enzyme release from neutrophils except for elastase, which is essential in the first phase of injury. Superoxide and nitric oxide generation under the influence of PR-39 and PGs were also decreased. Moreover, we found that unlike separated peptides PR-39 and PGs, LMWE acts proinflammatorily, intensifying the neutrophil secretory response and free radical generation. These results should be taken into account in treatment with natural antimicrobial peptides. The increased neutrophil responses in the first phase of inflammation during surgery may be useful in prevention of infection, but LMWE should not be used in conditions in which excessive neutrophil response is injurious.

Endosseous Implants in Non-vascularized Bone Grafts: Outcome Analysis

To evaluate osseointegration of dental implants placed into non-vascularized bone grafts and to assess differences in outcomes with regards to jaw defect (type, size, etiology) and type of graft (autograft, allograft, xenograft, and alloplast).

Engineering bone tissue substitutes from human induced pluripotent stem cells

Congenital defects, trauma, and disease can compromise the integrity and functionality of the skeletal system to the extent requiring implantation of bone grafts. Engineering of viable bone substitutes that can be personalized to meet specific clinical needs represents a promising therapeutic alternative. The aim of our study was to evaluate the utility of human-induced pluripotent stem cells (hiPSCs) for bone tissue engineering. We first induced three hiPSC lines with different tissue and reprogramming backgrounds into the mesenchymal lineages and used a combination of differentiation assays, surface antigen profiling, and global gene expression analysis to identify the lines exhibiting strong osteogenic differentiation potential. We then engineered functional bone substitutes by culturing hiPSC-derived mesenchymal progenitors on osteoconductive scaffolds in perfusion bioreactors and confirmed their phenotype stability in a subcutaneous implantation model for 12 wk. Molecular analysis confirmed that the maturation of bone substitutes in perfusion bioreactors results in global repression of cell proliferation and an increased expression of lineage-specific genes. These results pave the way for growing patient-specific bone substitutes for reconstructive treatments of the skeletal system and for constructing qualified experimental models of development and disease.

Effect of Implantation of Augment® Bone Graft on Serum Concentrations of Platelet-Derived Growth Factors: A Pharmacokinetic Study

Augment(®) Bone Graft is a bone graft substitute intended to be used as an alternative to autologous bone graft in the fusion of hindfoot and ankle joints. Augment(®) Bone Graft is a combination device comprised of beta-tricalcium phosphate (β-TCP) and recombinant human platelet-derived growth factor BB homodimer (rhPDGF-BB). This human pharmacokinetic study was undertaken to assess the effect of Augment(®) Bone Graft implantation on the serum concentration of platelet-derived growth factors (PDGFs). Under the terms of a Research Ethics Board-approved protocol, Augment(®) Bone Graft was implanted in patients (n = 7) undergoing hindfoot and ankle arthrodesis procedures requiring graft material. The control cohort of the study (n = 4) received autologous bone graft. The serum concentrations of PDGF isoforms AA, AB and BB in blood samples, obtained prior to and at ten time points (up to 7 days) after surgery, were measured using enzyme-linked immunosorbent assays (ELISA). The serum concentration of PDGF-BB did not vary significantly from baseline (median of the combined cohorts 3.89 ng/mL) throughout the course of the study. The serum concentrations of PDGF-AA, PDGF-AB and total PDGF did not deviate from their baseline values (medians of the combined cohorts were 2.87, 14.95 and 20.19 ng/mL for PDGF-AA, PDGF-AB and total PDGF, respectively) except for the last time point in which they were increased (medians for the combined cohorts were 4.71, 20.42 and 30.29 ng/mL for PDGF-AA, PDGF-AB and total PDGF, respectively). There were no differences between the two treatment groups with regard to changes in the serum concentrations of PDGF. None of the samples tested contained anti-PDGF-BB antibodies. Analysis of the data demonstrated that the serum concentrations of all three PDGF isoforms analysed were unaffected by implantation of Augment(®) Bone Graft.

Pharmacokinetic Properties and Systemic Safety of Vancomycin-Impregnated Cancellous Bone Grafts in the Treatment of Spondylodiscitis

The aim of the present study was to investigate the local pharmacokinetic properties and the systemic safety of vancomycin-impregnated cancellous bone grafts in the treatment of spondylodiscitis. Between 2010 and 2012, 8 patients (5 females, 3 males, mean age 68.75 y.) were treated with this method. Local vancomycin concentrations reached median values of 179 µg/mL (maximum 365 µg/mL) on day 1, decreasing to 98 µg/mL on day 3. The urine vancomycin concentrations showed similar pharmacokinetic properties as those locally determined. On day 1, median values were at 28.05 µg/mL (maximum 287 µg/mL). All serum vancomycin concentrations were in all cases and on every day below <2 µg/mL. The median serum creatinine values were preoperatively 0.87 mg/dL, followed by 0.625 mg/dL, 0.705 mg/dL, and 0.835 mg/dL on day 7, 14, and 28, respectively. No cases of ototoxicity could be observed. At a mean follow-up of 16.5 [4–36] months no cases of reinfections or persistent infections could be seen. In conclusion, the implantation of vancomycin-loaded cancellous bone grafts is an effective option in the treatment of spondylodiscitis with a high infection eradication rate and no risk of any systemic toxicity. The pharmacokinetic properties can be easily monitored locally, in the urine and the serum.

Outcome after thoracoscopic ventral stabilisation of thoracic and lumbar spine fractures

Background and PurposeThoracoscopic-assisted ventral stabilisation for thoracolumbar fractures has been shown to be associated with decreased recovery time and less morbidity when compared with open procedures. However, there are a limited number of studies evaluating late clinical and radiological results after thoracoscopic spinal surgery.MethodsWe performed an analysis of the late outcomes of thoracolumbar fractures after minimally invasive thoracoscopic ventral instrumentation. Between August 2003 and December 2008, 70 patients with thoracolumbar fractures (T5-L2) underwent ventral thoracoscopic stabilisation. Tricortical bone grafts, anterior plating systems (MACS-System), and cage implants were used for stabilisation. Outcomes measured include radiologic images (superior inferior endplate angle), Visual Analogue Scale (VAS), VAS Spine Score, quality of life scores SF-36 and Oswestry Disability Index (ODI).ResultsForty seven patients (67%, 47 out of 70) were recruited for the follow up evaluation (2.2 ± 1.5 years). Lower VAS Spine scores were calculated in patients with intra- or postoperative complications (44.7 (± 16.7) vs. 65.8 (± 24.5), p=0.0447). There was no difference in outcome between patients treated with bone graft vs. cage implants. Loss of correction was observed in both bone graft and titanium cage groups.InterpretationThe present study demonstrates diminished long-term quality of life in patients treated with thoracoscopic ventral spine when compared with the outcome of german reference population. In contrast to the other patients, those patients without intra-operative or post-operative complications were associated with improved outcome. The stabilisation method (bone graft versus spinal cage) did not affect the long-term clinical or radiographic results in this series.

Endoscopically assisted allogeneic bone grafting for atrophic nonunion of femur and tibia

BackgroundThe nonunion rate for all fractures is about 5–10%. The treatment of nonunion is based on the biologic and mechanical factors contributing to the cause of the nonunion. Debridement and bone grafting are the standard procedures used to treat nonunion of fractures. PurposeWe evaluated the results of endoscopically assisted allogeneic bone grafting performed to treat the nonunion of tibial and femoral fractures. MethodsBetween May 2006 and January 2011, eight patients (two men and six women) with tibial or femoral fracture nonunion were enrolled into our study. The average age of the patients was 35.4 years (range, 24–56 years). All patients underwent endoscopically assisted allogeneic bone graft implantation. We recorded the union status, clinical symptoms, and complications in all patients. ResultsThe average time from the fracture to surgery was 14.4 months (range, 9–22 months). The average follow-up period was 19.1 months (range, 9–28 months). Seven patients achieved bone union and only one patient required additional surgery. The average time between surgery and bone union was 6.4 months (range, 4–8 months). No major complications were reported. ConclusionEndoscopically assisted allogeneic bone grafting is a less invasive and effective treatment for atrophic nonunion of fractures.

Advancing with Ceramic Biocomposites for Bone Graft Implants

Advancing with Ceramic Biocomposites for Bone Graft Implants

Advancing with Ceramic Biocomposites for Bone Graft Implants

Bone grafting has come a very long way since a Dutch surgeon used pieces of a dog's skull to repair a soldier's cranium in the 17 th Century. Current technology aims to deliver a scaffold that combines the unique osteogenic properties of ceramic biocomposite materials to make the best mimic of physiologic conditions. To do so, a scaffold must provide: i) A three-dimensional platform allowing for osteogenic cellular attachment and growth and vascular formation, ii) Struc- tural integrity while the damaged tissue heals, and iii) Non-toxic integration, degradation or resorption into the host over an appropriate time. The combination of inorganic, ceramic materials with cells, polymers and growth factors has come very close to creating a bone graft capable of meeting each of these requirements. Recent patents describe new methods to forming an ideal osteogenic matrix for both large and small bone repair. Many new technologies have been introduced that are very potent in their ability to heal small bone wounds and induce new bone formation, such as porous calcium phosphate pastes and hydroxyapatite cements. However, there is still a lack of quality and proven materials for load bear- ing purposes. This is a reminder of how much there still is to improve upon and that we are still a long way from creating bone products that are identical to the natural product. Despite these shortcomings, ceramic biocomposties represent one of the most promising materials in the bone graft field and their development and improvement will surely lead to a more natural bone replacement.

Effect of zoledronate acid treatment on osseointegration and fixation of implants in autologous iliac bone grafts in ovariectomized rabbits

One main problem associated with alveolar bone augmentation in implant dentistry is resorption of grafted bone, which may be further compromised by systemic skeletal disorders such as osteoporosis. Zoledronate acid (ZOL) is the most potent bisphosphonate to treat osteoporosis and therefore it is hypothesized to be able to invert the negative effect of osteoporosis on osseointegration and fixation of dental implants in autologous bone grafts. In this study, 56 rabbits received bilateral ovariectomy (OVX) (40 rabbits) or sham operation (16 rabbits). Three months later, 8 animals from each group were sacrificed for bone mineral density (BMD) examination. Then the remaining animals underwent bilateral autologous iliac bone grafting with simultaneous implantation of titanium implants in tibiae and were divided into 5 groups (n=8): Sham, OVX, Loc-ZOL (local treatment), Sys-ZOL (systemic treatment) and Loc+Sys-ZOL (local plus systemic) group. At 3 months after implantation, all animals were sacrificed and specimens were harvested for examinations. Both BMD and histological examinations of femurs showed osteoporotic changes after ovariectomy, while systemic treatment with ZOL restored mineralized bone. Micro-CT examination demonstrated that OVX group showed significant decrease of mineralized bone and implant-bone contact when compared with sham control, whereas both systemic and local treatments of ZOL significantly increased mineralized bone and implant-bone contact in ovariectomized animals. However, the best effects were observed in Loc+Sys-ZOL group (combined use of ZOL) and most of bone indices were similar to (IBCR, p>0.05) or higher than (BV/TV, Conn.D and Tb.N) (p<0.01) those of the sham group, except Tb.Th, which was still significantly lower (p<0.01), and Tb.Sp, which was further decreased (p<0.01). The aforementioned effects were also confirmed by histomorphometric analysis of bone indices on implant-bone contact and mineralized bone. In addition, biomechanical testing further supported the beneficial effect of ZOL treatment and maximal removal torque of titanium implants was observed in Loc+Sys-ZOL group. In conclusion, our study suggests that both systemic and local treatments with ZOL can invert negative effect of osteoporosis and promote osseointegration and fixation of dental implants in autologous bone grafts under osteoporotic condition. Combined systemic and local use of ZOL exerts best effects when compared to their single use.

Periodontal healing following reconstructive surgery: effect of guided tissue regeneration using a bioresorbable barrier device when combined with autogenous bone grafting. A randomized‐controlled trial 10‐year follow‐up

The objective of this 10-year randomized-controlled trial follow-up was to evaluate the stability of treatment outcomes following the implantation of autogenous bone graft with or without guided tissue regeneration (GTR) in the treatment of deep intra-bony periodontal defects. Forty patients exhibiting deep intra-bony periodontal defects were included in a randomized-controlled trial evaluating the adjunctive effect of GTR to autogenous bone graft. Twenty-six of 39 patients completing the original study were available for follow-up 10 years post-treatment. The patients had been included in a structured maintenance programme and were evaluated using the criteria of the original study by the same investigators. Significant improvements in the probing depth and clinical attachment level were observed for both groups between baseline and 9 months. Whereas the autogenous bone graft+GTR group showed significant improvements in probing bone levels and increased gingival recession at 9 months, no significant differences were observed for the autogenous bone graft group. Nine-month within-group results were maintained throughout the 10-year follow-up. Nevertheless, between-group comparisons at 10 years showed that the autogenous bone graft+GTR group exhibited significantly greater probing depth reduction (mean +/- SE: 4.2 +/- 0.5 versus 2.7 +/- 0.5 mm, p=0.023) and probing bone-level gain (3.9 +/- 0.8 versus 1.3 +/- 0.9 mm, p=0.034) than the autogenous bone graft group. Borderline significant differences between the autogenous bone graft+GTR and the autogenous bone graft groups were observed for clinical attachment level gain at 10 years (3.8 +/- 0.5 versus 2.2 +/- 0.7 mm, p=0.067), whereas no significant differences were observed for gingival recession (0.7 +/- 0.3 versus 0.6 +/- 0.5 mm, p>0.05). The results of this randomized study suggest that statistically significant differences were found with the adjunct use of GTR to an autogenous bone graft at 10 years. Nevertheless, these results should be interpreted with caution in light of its clinical relevance and biological rationale. Importantly, resolution of deep intra-bony periodontal defects can be maintained in the presence of a structured maintenance programme emphasizing high oral hygiene standards.

Influence of platelet-rich plasma on the anterior fusion in spinal injuries: a qualitative and quantitative analysis using computer tomography

The effects of platelet-rich plasma (PRP) were monitored by performing a controlled cohort study of patients undergoing an anterior spinal fusion. One group was treated with the addition of PRP. The growth factors contained within the blood platelets are known to play an important role in the new formation of bone following fractures or the implantation of bone grafts. But the results following the use of PRP in spinal fusion are not yet published. The study involved a group of 15 patients, who had suffered an injury of the thoracic or lumbar spine and had undergone an anterior fusion using cages. They had received an additional posterior stabilisation and/or anterior implants as well as bone graft combined with PRP. A control group made up of 20 patients received a similar treatment, but without the addition of PRP. A CT scan was performed of all patients during follow-up examinations. The area on the left side of the cage, where the bone graft with or without PRP had been applied, was analysed and the patients were divided into three classes, depending upon the rate of fusion: complete fusion, incomplete fusion and no/minimal ossification. In cases which were classified as complete or incomplete ossification, an additional CT volumetry and densitometry was performed. The patient-referred outcome was documented using the VAS spinal score. In both groups, 40% of the patients had reached a complete fusion in the CT scans. No or minimal fusion was documented in 20% of the PRP group and 30% of the control group. When measuring the density within the newly formed bone mass, both groups showed nearly identical percentages with a density of over 100 Hounsfield units (HU). The share of bone with a density of over +500 HU was 29.33% in the PRP group and 23.57% in the control group. Within the partition of over +100 HU, the absolute density was significantly higher in the PRP group (639.7 vs. 514.2 HU). Similar results could be shown within the partition of over +500 HU (930.7 vs. 846 HU). The VAS scores showed no significant differences between the two groups. The additional application of autologous PRP involves very little risk for the patients. The study implies that the use of PRP provides a faster fusion and higher density values within the fusion mass. A clear advancement in spinal fusion in terms of a clinical benefit remains questionable.