Platelet gel (AGF) fails to increase fusion rates in instrumented posterolateral fusions

Efficacy of using autologous cells with graft substitutes for spinal fusion surgery: A systematic review and meta-analysis of clinical outcomes and imaging features

Over the past several decades, there has been a notable increase in the total number of spinal fusion procedures worldwide. Advanced spinal fusion techniques, surgical approaches, and new alternatives in grafting materials and implants, as well as autologous cellular therapies, have been widely employed for treating spinal diseases. While the potential of cellular therapies to yield better clinical results is appealing, supportive data are needed to confirm this claim. This meta-analysis aims to compare the radiographic and clinical outcomes between graft substitutes with autologous cell therapies and graft substitutes alone. PubMed, Scopus, Web of Science, ClinicalTrials.gov, and the Cochrane Central Register of Controlled Trials were searched for studies comparing graft substitutes with autologous cell therapies and graft substitutes alone up to February 2024. The risk of bias of the included studies was evaluated using the Downs and Black checklist. The following outcomes were extracted for comparison: fusion success, complications/adverse events, Visual Analog Scale (VAS) score, and Oswestry Disability Index (ODI) score. Thirteen studies involving 836 patients were included, with 7 studies considered for the meta-analysis. Results indicated that the use of graft substitutes with autologous cell therapies demonstrated higher fusion success rates at 3, 6, and 12 months, lower VAS score at 6 months, and lower ODI score at 3, 6, and 12 months. The complication rate was similar between graft substitutes with autologous cell therapies and graft substitutes alone. Although the current literature remains limited, this meta-analysis suggests that the incorporation of cellular therapies such as bone marrow and platelet derivatives with graft substitutes is associated with a higher fusion rate and significant improvements in functional status and pain following spinal fusion. Future well-designed randomized clinical trials are needed to definitively assess the clinical effectiveness of cellular therapies in spinal fusion.

Using a developed co-culture device to evaluate the proliferation of bone marrow stem cells by stimulation with platelet-rich plasma and electromagnetic field

BACKGROUNDS

Bone marrow stem cell can differentiate to osteoblast by growth factors, pulsed low-intensity ultrasound and electric magnetic field. In the research, bone marrow stem cells were cultured; bone marrow stem cells in culture can be stimulated by platelet-rich plasma and electric field.

METHODS

The culture well of the co-cultivation device has a radius of 7.5 mm and a depth of 7 mm. It is divided into two sub-chambers separated by a 3 mm high and 1 mm wide barrier. The bone marrow stem cells were seeded at a density of 2 × 104 cells and the medium volume was 120μl. Platelet-rich plasma (PRP) or platelet-poor plasma (PPP) was added to the other sub-chamber at a volume of 10μl. The bone marrow stem cells were subjected to different electric fields (0 ~ 1 V/cm) at a frequency of 70 kHz for 60 min.

RESULTS

The highest osteogenic capacity of bone marrow stem cells was achieved by addition of PRP to electric field stimulation (0.25 V/cm) resulted in a proliferation rate of 599.78%. In electric field stimulation (0.75 V/cm) with PPP, the proliferation rate was only 10.46%.

CONCLUSIONS

Bone marrow stem cell with PRP in the co-culture device combined with electric field at 0.25 V/cm strength significantly promoted the growth of bone marrow stem cells.

Combined effect of DBM, PRP, and bone marrow fluid on bone union in a rat posterolateral fusion model

Platelet-rich plasma (PRP) promotes bone union through osteoinduction. We investigated whether adding demineralized bone matrix (DBM), derived naturally from biomaterial and with various growth factors, for osteoconductivity and bone marrow fluid for osteogenesis results in different bone unions. Eight-week-old male Sprague-Dawley rats were divided into four groups of five based on transplantation material: sham control (C group); DBM alone (D group); DBM + PRP (DP group); and DBM + PRP + bone marrow fluid (DPB group). After posterolateral fusion at L3-5, postoperative weekly CT imaging determined average number of bone union in facet joints (4 joints × 5 animals = 20 joints) and bone formation. Pathological evaluation and bone strength were assessed using 3-point bending two weeks postoperatively. Facet joint bone union at four weeks postoperatively was 4/20 (20%, DP group) and 8/20 (40%, DPB group) joints. Six weeks postoperatively, it was 7/20 (35%, D group), 12/20 (60%, DP group), and 16/20 (80%, DPB group). Eight weeks postoperatively, it was 13/20 (65%, D group), 17/20 (85%, DP group), and 20/20 (100%, DPB group), suggesting that DPB > DP > D > C. Bone formation and bone strength showed a similar DPB > DP > D > C group trend. Adding PRP and bone marrow fluid to DBM promotes bone union and strength.

Advances in Platelet-Rich Plasma Treatment for Spinal Diseases: A Systematic Review

Spinal diseases are commonly associated with pain and neurological symptoms, which negatively impact patients' quality of life. Platelet-rich plasma (PRP) is an autologous source of multiple growth factors and cytokines, with the potential to promote tissue regeneration. Recently, PRP has been widely used for the treatment of musculoskeletal diseases, including spinal diseases, in clinics. Given the increasing popularity of PRP therapy, this article examines the current literature for basic research and emerging clinical applications of this therapy for treating spinal diseases. First, we review in vitro and in vivo studies, evaluating the potential of PRP in repairing intervertebral disc degeneration, promoting bone union in spinal fusion surgeries, and aiding in neurological recovery from spinal cord injury. Second, we address the clinical applications of PRP in treating degenerative spinal disease, including its analgesic effect on low back pain and radicular pain, as well as accelerating bone union during spinal fusion surgery. Basic research demonstrates the promising regenerative potential of PRP, and clinical studies have reported on the safety and efficacy of PRP therapy for treating several spinal diseases. Nevertheless, further high-quality randomized controlled trials would be required to establish clinical evidence of PRP therapy.

The efficacy of platelet-rich plasma applicated in spinal fusion surgery: A meta-analysis

Objective

The purpose of this meta-analysis is to evaluate the effect of the application of platelet-rich plasma (PRP) in spinal fusion surgery on the fusion rate of the spine.

Methods

A comprehensive search of the PubMed, Embase, Cochrane Library, and Science Direct databases was conducted to identify randomized control trials (RCTs) or observational cohort studies that evaluated the efficacy and safety of PRP in spinal fusion. Data on final fusion rate, changes in the visual analog scale (VAS), estimated blood loss (EBL), and operative time was collected from the eligible studies for meta-analysis. Patients were divided into PRP and non-PRP groups according to whether PRP was used during the spinal fusion procedure.

Results

According to the selection criteria, 4 randomized controlled trials and 8 cohort studies with 833 patients and 918 levels were included. The outcomes indicated that PRP application is associated with a lower fusion rat (OR = 0.62, 95% CI: (0.43, 0.89), P = 0.009) at final follow-up (>24 months). Subgroup analysis showed a lower rate of spinal fusion in the PRP group compared to the non-PRP group (OR = 0.35, 95% CI: (0.21, 0.58), P < 0.001) when spinal fusion was assessed using only anterior-posterior radiographs. When the bone graft material was a combination of autologous bone + artificial bone, the spinal fusion rate was lower in the PRP group than in the non-PRP group (OR = 0.34, 95% CI: (0.16, 0.71), P = 0.004). The PRP and non-PRP groups showed no significant differences in VAS changes at the 24th postoperative month (WMD = 0.36, 95% CI: (−0.37, 1.09), P = 0.33); Application of PRP does not reduce the estimated blood loss (WMD = −86.03, 95% CI: (−188.23, 16.17), P = 0.10). In terms of operation time, using PRP does not prolong operation time (WMD = −3.74, 95% CI: (−20.53, 13.04), P = 0.66).

Conclusion

Compared with bone graft fusion alone, PRP cannot increase the rate of spinal fusion. Inappropriate methods of spinal fusion assessment or mixing PRP with artificial/allograft bone may have been responsible for the lower rate of spinal fusion in the PRP group.

Systematic Review Registration

doi: 10.37766/inplasy2022.5.0055

Biomaterials for Interbody Fusion in Bone Tissue Engineering

In recent years, interbody fusion cages have played an important role in interbody fusion surgery for treating diseases like disc protrusion and spondylolisthesis. However, traditional cages cannot achieve satisfactory results due to their unreasonable design, poor material biocompatibility, and induced osteogenesis ability, limiting their application. There are currently 3 ways to improve the fusion effect, as follows. First, the interbody fusion cage is designed to facilitate bone ingrowth through the preliminary design. Second, choose interbody fusion cages made of different materials to meet the variable needs of interbody fusion. Finally, complete post-processing steps, such as coating the designed cage, to achieve a suitable osseointegration microstructure, and add other bioactive materials to achieve the most suitable biological microenvironment of bone tissue and improve the fusion effect. The focus of this review is on the design methods of interbody fusion cages, a comparison of the advantages and disadvantages of various materials, the influence of post-processing techniques and additional materials on interbody fusion, and the prospects for the future development of interbody fusion cages.

Is Platelet-Rich Plasma Effective in Enhancing Spinal Fusion? Systematic Overview of Overlapping Meta-Analyses

STUDY DESIGN

Systematic review.

OBJECTIVES

We performed this systematic overview on overlapping meta-analyses that analyzed the role of platelet-rich plasma(PRP) in enhancing spinal fusion and identify which study provides the current best evidence on the topic and generate recommendations for the same.

MATERIALS AND METHODS

We conducted independent and duplicate electronic database searches in PubMed, Web of Science, Embase, Cochrane Database of Systematic Reviews, and Database of Abstracts of Reviews of Effects till October-2020 for meta-analyses that analyzed the role of PRP in spinal fusion procedures. Methodological quality assessment was made using Oxford Levels of Evidence, AMSTAR scoring, and AMSTAR 2 grades. We then utilized the Jadad decision algorithm to identify the study with highest quality to represent the current best evidence to generate recommendations.

RESULTS

3 meta-analyses fulfilling the eligibility criteria were included. The AMSTAR scores of included studies varied from 5-8(mean:6.3) and all included studies had critically low reliability in their summary of results due to their methodological flaws according to AMSTAR 2 grades. The current best evidence showed that utilization of PRP was not associated with significant improvement in patient-reported outcomes such as Visual Analog Score for pain compared to the standard fusion procedure. Moreover, PRP was found to be associated with lower fusion rates.

CONCLUSION

Based on this systematic overview, the effectiveness of PRP as a biological agent in augmenting spinal fusion is limited. Current evidence does not support the use of PRP as an adjuvant to enhance spinal fusion.

The role of Platelet Rich Plasma and other orthobiologics in bone healing and fracture management: A systematic review

BACKGROUND

Treatment of large bone defects and fracture healing complications (delayed and non-union) presents a substantial challenge for orthopaedic surgeons. Given that bone healing requires mechanical stability as well as a favourable biological microenvironment, orthobiologics such as Platelet-Rich Plasma (PRP) may have a significant clinical role to play.

AIMS

To perform a systematic review of the available literature to assess the clinical effect of PRP, with or without other orthobiologics, on bone healing.

METHOD

Two independent reviewers performed the literature search based on the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Clinical studies of any evidence, assessing effect of PRP with or without other orthobiologics on bone healing, were included. A qualitative analysis was carried out on the clinical and radiological outcomes reported.

RESULT

27 articles with 1631 patients (mean age = 43.56, 57.1% male, mean follow-up = 17.27 months) were included in the qualitative. Of the 27 studies, 13 dealt with fracture complications (delayed or non-unions), 7 with acute fracture healing, 4 with tibial osteotomies and lengthening procedures and 3 with lumbar spine pathology. 18/27 studies showed a clinical benefit of PRP, 8/27 showed no significant effect, and 1/27 showed a worse outcome with PRP.

CONCLUSION

Our review suggests PRP may play a clinical role in bone healing but further randomised controlled trials (RCTs) using standardised outcomes should be performed to establish its efficacy.

Autologous platelet-rich fibrin (PRF) augmentation as an add-on therapy in deep surgical site infections (dSSIs) after instrumented spinal surgery: preliminary results of a single institution case series

BACKGROUND

Deep surgical site infections (dSSIs) after instrumented spinal surgery pose major therapeutic challenges. Standard treatment involves surgical debridement, wound drainage, and long-term antibiotic administration. Autologous platelet-rich fibrin (PRF) constitutes a biomaterial obtained from patients' own blood that contains leukocytes, chemokines and growth factors boosting cicatrization. Due to favorable results reported from other surgical disciplines such as dentistry, orthopedics, maxillofacial and plastic surgery using PRF, the authors hypothesized that PRF augmentation will promote wound healing in dSSIs.

OBJECTIVE

To report our preliminary results on the safety and efficacy of autologous-PRF as an add-on therapy on a pilot case series of persistent dSSI after instrumented spinal surgery.

METHODS

Among the 293 patients who underwent dorsal decompression and stabilization of the cervical, thoracic, and lumbar spine due to degenerative diseases in our department, 12 patients (4%) presented persisting dSSI after standard wound debridement and antibiotic treatment. PRF augmentation was used during a second surgical revision as an add-on therapy to standard debridement. In all cases, the wound was primarily closed without drains.

RESULTS

Wound healing was completed between 14 and 21 days after the second surgical revision in all patients. At a median follow-up of 8 months (range: 6 to 18 months), no recurrence of dSSI nor complications were encountered in any case.

CONCLUSIONS

Our preliminary results suggest that PRF augmentation in persistent dSSI after instrumented spinal surgery appears to be a safe and effective strategy to promote wound healing. Prospective controlled studies are required to define the efficiency of PRF more clearly in both treating and preventing dSSI.

Platelet Concentrate In Lumbar Interbody Cage Fusion: A New Era of Modality Of Fusion

AIM: This was a prospective double-blinded randomized comparative study. Several authors have reported the efficacy of platelets derivatives for spinal union. However, the use of PRP and PRF for bone fusion with TLIF has not been fully explored. METHODS: Standard open TLIF surgery was performed on 80 patients, randomized in three groups, TLIF and local bone were used in 40 patients (control group) and TLIF, local bone, and PRP were used in 20 patients (PRP group) and PRF was used in 20 patients (PRF group). Radiological parameters were assessed by X-ray after 3 months post-operative to evaluate the position of the screws and cage migration and by CT scans at 6 months and 12 months postoperatively. Patients, surgeons, and post-surgical analysis were blinded. RESULTS: VAS scores for lower back pain and leg pain were statistically significant between the three groups preoperatively. The VAS scores of back pain improved after 12 months and were statistically significant (p < 0.001) and the VAS score of leg pain improved compared with preoperatively in the three groups during the 6- and 12-month follow-up postoperatively, however, the three groups, VAS scores for leg pain were not significantly different. After 1-year follow-up, significantly more patients achieved definite fusion, when implanted platelets derivatives compared with the control group, but with no significance regarding fusion rates. CONCLUSION: We advocated using platelet derivative as a fusion enhancer modality which is cost and time saving. It appears to be a complementary step that ensures better outcome for the patients.

Current applications of platelet gels in wound healing-A review

Human platelets play important roles in several physiologic and pathologic processes. Platelet concentrates are activated with thrombin or calcium, resulting in a viscous coagulum (platelet gel [PG]), composed of 95% platelets at least. PG is increasingly used for the treatment of a variety of soft and hard tissue defects, most notably in the management of chronic non-healing wounds. During wound healing, platelets not only play a critical role in primary hemostasis and thrombosis, but also release growth factors and cytokines to promote tissue regeneration, enhance collagen synthesis, and trigger an immune response. This review addresses a variety of aspects relevant to the functions of well-known platelet growth factors, animal and clinical studies of PG in the last decade, and different sources of platelets for PG. PG is used for non-healing chronic wounds, such as oral ulcerations related to epidermolysis bullosa and chronic graft-versus-host disease, for those, the traditional treatment effect is poor. PG maybe provide a new therapeutic direction for these diseases. Nevertheless, some uncertainty is present, the number of clinical studies is not enough. Hence, randomized controlled trials are still required to study the potential of the use of PG in the near future.

The Use of Platelet-Rich Plasma (PRP) for the Management of Non-union Fractures

PURPOSE OF REVIEW

The treatment of non-union fractures represents a significant challenge for orthopaedic surgeons. In recent years, biologic agents have been investigated and utilised to support and improve bone healing. Among these agents, platelet-rich plasma (PRP) is an emerging strategy that is gaining popularity. The aim of this review is to evaluate the current literature regarding the application and clinical effectiveness of PRP injections, specifically for the treatment of non-union fractures.

RECENT FINDINGS

The majority of published studies reported that PRP accelerated fracture healing; however, this evidence was predominantly level IV. The lack of randomised, clinical trials (level I-II evidence) is currently hampering the successful clinical translation of PRP as a therapy for non-union fractures. This is despite the positive reports regarding its potential to heal non-union fractures, when used in isolation or in combination with other forms of treatment. Future recommendations to facilitate clinical translation and acceptance of PRP as a therapy include the need to investigate the effects of administering higher volumes of PRP (i.e. 5-20 mL) along with the requirement for more prolonged (> 11 months) randomised clinical trials.

Platelet Rich Plasma in Orthopedic Surgical Medicine

There is a global interest in optimizing post-surgical tissue repair strategies, leading to better patient outcomes and fewer complications, most ideally with reduced overall cost. In this regard, in recent years, the interest in autologous biological treatments in orthopedic surgery and sports medicine has increased greatly, and the addition of platelet-rich plasma (PRP) to the surgical armamentarium is of particular note. Unfortunately, the number of PRP preparation devices has also grown immensely over the recent decades, raising meaningful concern for the considerable variation in the qualities of currently available PRP preparations. The lack of consensus on the standardization of PRP preparation and of agreement on condition specific PRP formulations is largely responsible for the sometimes contradictory outcomes in the literature. Furthermore, the full potential of PRP technology, the concept of individualized treatment protocols based on bioformulation options, and platelet dosing, angiogenesis, and antimicrobial and painkilling effects of PRP relevant to orthopedic surgery have rarely been addressed. In this review, we will discuss recent developments regarding PRP preparations and potential therapeutic effects. Additionally, we present a synopsis of several published data regarding PRP applications in orthopedic surgery for treating tendon injuries, inducing bone repair, strengthening spinal fusion outcomes, and supporting major joint replacements.

Assisted therapy with platelet-rich plasma for burn patients: A meta-analysis and systematic review

INTRODUCTION

Platelet-rich plasma (PRP) therapy has been used in different medical fields, but its effectiveness in burn wound healing remains debatable. In this study, we performed a systematic review and meta-analysis of the available evidence on burn patients treated with PRP to evaluate the safety and efficacy of the treatment.

METHODS

Randomized controlled trials evaluating the efficacy of PRP in patients with burn injuries were selected. Eligible retrospective studies were abstracted and assessed for the risk of bias by two reviewers and results of mean time to complete epithelization and wound closure rate in the included studies were analyzed. Studies on the correlation between PRP and burn wound healing published in English or Chinese before March 2020 were retrieved from PubMed.

RESULTS

Eight studies (including 449 patients) met our inclusion criteria. Qualitative analysis revealed that compared with the control group, the PRP group had significantly better wound closure rates at weeks 2 (mean difference (MD): 12.79 [95% confidence interval (CI): 7.08, 18.49]; I2: 0%; p < 0.0001) and 3 (MD: 12.66 [95% CI: 5.97, 19.34]; I2: 55%; p = 0.0002) and time to complete epithelialization (MD: -3.45 [95% CI: -4.87, -2.04] (days); I2: 0%; p < 0.00001). There was no significant difference in infection rate or graft take rate.

CONCLUSIONS

PRP application can accelerate wound closure, however, it has no effect on the rates of wound infection and graft take rate.

The impact of platelet-rich plasma on postoperative outcomes after spinal fusion: a systematic review and meta-analysis

OBJECTIVE

Platelet-rich plasma (PRP) is a biological agent obtained by centrifuging a sample of blood and retrieving a high concentration of platelets and plasma components. The concentrate is then stimulated for platelet secretion of various growth factors and cytokines. Although it is not widely used in clinical practice, its role in augmenting bony union among patients undergoing spinal fusion has been assessed in several clinical studies. The objective of this study was to perform a systematic review and meta-analysis of the existing literature to determine the efficacy of PRP use in spinal fusion procedures.

METHODS

A comprehensive literature search was conducted using PubMed, Scopus, and EMBASE for studies from all available dates. From eligible studies, data regarding the fusion rate and method of assessing fusion, estimated blood loss (EBL), and baseline and final visual analog scale (VAS) scores were collected as the primary outcomes of interest. Patients were grouped by those undergoing spinal fusion with PRP and bone graft (PRP group) and those only with bone graft (graft-only group).

RESULTS

The literature search resulted in 207 articles. Forty-five full-text articles were screened, of which 11 studies were included, resulting in a meta-analysis including 741 patients. Patients without PRP were more likely to have a successful fusion at the last follow-up compared with those with PRP in their bone grafts (OR 0.53, 95% CI 0.34-0.84; p = 0.006). There was no statistically significant difference with regard to change in VAS scores (OR 0.00, 95% CI -2.84 to 2.84; p > 0.99) or change in EBL (OR 3.67, 95% CI -67.13-74.48; p = 0.92) between the groups.

CONCLUSIONS

This study found that the additional use of PRP was not associated with any significant improvement in patient-reported outcomes and was actually found to be associated with lower fusion rates compared with standard grafting techniques. Thus, PRP may have a limited role in augmenting spinal fusion.

Role of Platelet-Rich Plasma in Spinal Fusion Surgery: Systematic Review and Meta-Analysis

Background

Platelet-rich plasma (PRP) has been used very successfully in enhancing bone fusion in animal experiments. Also, the efficaciousness of PRP in other specialties of medicine such as dentistry, dermatology ophthalmology, and sports medicine is well documented. But the use of PRP to augment bone fusion after spinal surgery in humans is still controversial. We conducted a meta-analysis to determine the role of PRP in enhancing spinal fusion by fastening the rate of new bone formation and decreasing pain after spinal surgery in humans.

Methods

We searched PubMed, EMBASE, and the Cochrane Library studies that compared PRP versus control in enhancing spinal fusion after deformity correction.

Results

Five retrospective studies with 253 participants and nine prospective cohort studies with 460 participants were identified. The bone fusion rate was excellent for studies that used a high platelet concentration in PRP relative to control (odds ratio (OR) = 4.35, 95% confidence interval (CI) (2.13, 8.83), and P < 0.05) while bone fusion was poor to studies that used a low concentrate of platelet in PRP relative to control. The rate of new bone formation was high in the PRP group compared to the control group with the mean difference in Hounsfield unit (HU) 144.91 (95% CI (80.63, 209.18), P < 0.05). Time to bone fusion was short in the PRP group during the first six months of surgery relative to the control group with a mean difference of −2.03 (95% CI (−2.35, −1.7); P < 0.05). No difference was found in pain reduction by visual analog score (VAS) between the PRP group and control.

Conclusion

PRP facilitates new bone formation and bone fusion with a minimum concentration of the growth factor 5 times that of the peripheral blood. PRP stimulatory effects are not continuous and are very effective within six months of implantation.

Efficacy of Using Platelet-Rich Plasma in Spinal Fusion Surgery-A Preferred Reporting Items for Systematic Reviews and Meta-Analyses-Compliant Meta-Analysis

BACKGROUND

Platelet-rich plasma (PRP) has been frequently used to enhance bone regeneration. A meta-analysis was conducted to systematically assess the fusion rate and pain relief of applying PRP during spinal fusion surgery.

METHODS

Studies investigating spinal fusion surgery combined with PRP were retrieved from Medline and the Web of Science in accordance with the inclusion and exclusion criteria. A quality evaluation was conducted using the Cochrane collaboration tool for randomized controlled trials and the Newcastle-Ottawa scale quality assessment for cohort trials. Statistical analysis was performed using RevMan, version 5.3.

RESULTS

A total of 12 studies, including 3 randomized controlled trials and 9 cohort studies, with 661 patients, were included in the present meta-analysis. The mean age was 52.3 ± 8.0 years. Overall, the pooled results demonstrated that the differences in the fusion rates between the PRP and non-PRP treatment groups were not statistically significant. The risk ratio was 1.01 (95% confidence interval, 0.95-1.06; P = 0.83). Also, no significant difference in pain relief measured using the visual analog scale was found between the 2 groups. The mean difference was -0.08 (95% confidence interval, -0.26 to 0.11; P = 0.42).

CONCLUSIONS

Adding PRP did not increase the fusion rates from spinal fusion surgery. In addition, no significant difference was found in pain relief between the PRP and non-PRP treatment groups.

The use of platelet-rich fibrin in lumbar interbody fusion in lytic spondylolisthesis

Study Design:

This was a retrospective observational study.

Aim:

The aim of this study was to evaluate the effectiveness of applying the platelet-rich fibrin (PRF) with bone graft in accelerating the rate of lumbar interbody fusion.

Settings and Design:

This was a retrospective study measuring the outcome of posterior lumbar interbody fusion (PLIF) combined with PRF versus PLIF alone in the management of lytic spondylolisthesis.

Subjects and Methods:

Forty patients were treated with instrumented PLIF for low-grade lytic spondylolisthesis and divided into two equal groups: one with addition of PRF to the bone graft and the other without. The minimum follow-up was 2 years. Clinical outcome was measured by the Oswestry Disability Index (ODI) and Visual Analogue Pain Scale (VAS) at 3, 6, and 12 months postoperatively. Radiological outcome was measured by standing X-ray at 3, 6, 12, and 24 months and computed tomography at 6 and 12 months postoperatively.

Results:

ODI for the PRF group improved by 60% and 79% at 6 and 12 months, respectively, whereas for the non-PRF group, it improved by 55% and 70%. Radiological outcome showed fusion in 15 of 20 cases in the PRF group (75%) by the 6^th month and in 19 of 20 cases (95%) by 1 year and 100% at 2 years. In the control group, fusion was present in 12 of 20 cases (60%) by the 6^th month and in 13 of 20 cases in the PRF group (65%) by 1 year and 90% at 2 years (P < 0.05).

Conclusions:

These preliminary results show that PRF accelerates the rate of fusion in low-grade lytic spondylolisthesis in short-term follow-up.

Graft Materials and Biologics for Spinal Interbody Fusion

Spinal fusion is the most widely performed procedure in spine surgery. It is the preferred treatment for a wide variety of pathologies including degenerative disc disease, spondylolisthesis, segmental instability, and deformity. Surgeons have the choice of fusing vertebrae by utilizing cages containing autografts, allografts, demineralized bone matrices (DBMs), or graft substitutes such as ceramic scaffolds. Autografts from the iliac spine are the most commonly used as they offer osteogenic, osteoinductive, and osteoconductive capabilities, all while avoiding immune system rejection. Allografts obtained from cadavers and living donors can also be advantageous as they lack the need for graft extraction from the patient. DBMs are acid-extracted organic allografts with osteoinductive properties. Ceramic grafts containing hydroxyapatite can be readily manufactured and are able to provide osteoinductive support while having a long shelf life. Further, bone-morphogenetic proteins (BMPs), mesenchymal stem cells (MSCs), synthetic peptides, and autologous growth factors are currently being optimized to assist in improving vertebral fusion. Genetic therapies utilizing viral transduction are also currently being devised. This review provides an overview of the advantages, disadvantages, and future directions of currently available graft materials. The current literature on growth factors, stem cells, and genetic therapy is also discussed.

Platelet-rich plasma for the spinal fusion

There has been a wide interest in using platelet-rich plasma (PRP) as a therapeutic agent to enhance spinal fusion. There are two review articles based only on clinical studies regarding the effect of PRP on spinal fusion. However, with regard to both animal model studies and clinical studies, there is no review studies regarding its effect on spinal fusion and no review studies focusing on the platelet count and the concentration of the growth factor in the PRP. The purpose is to review the literatures about the effect of PRP on spinal fusion according to the animal model studies and clinical studies, focusing on the effect of the platelet count and the concentration of the growth factor in the PRP. A PubMed search was performed for English-language articles. We identified 20 articles regarding the effect of PRP on fusion in animal model studies and clinical studies, of which 16 articles met the study criteria of case-control studies or prospective randomized studies for the spinal fusion. The articles were categorized into small-sized animal model, middle-sized animal model, and clinical studies. Studies have shown both beneficial and inhibitory effects. The conclusion that PRP has the stimulating effect on spinal fusion was not reached. However, PRP might promote the human spinal fusion if the platelet count or the concentration of growth factors in the PRP increases.

Positive effect on spinal fusion by the combination of platelet-rich plasma and collagen-mineral scaffold using lumbar posterolateral fusion model in rats

Background

Platelet-rich plasma (PRP) is autologous in origin and contains a high concentration of platelets which is a source of various growth factors. Previous studies have suggested that PRP has a positive effect in accelerating fusion by an autologous bone graft in a lumbar fusion. The role of PRP on artificial bone grafts in spinal fusion remains controversial. In this study, positive effect on spinal fusion by PRP was hypothesized; in vitro and in vivo studies were designed to test this hypothesis.

Methods

PRP was produced from peripheral blood of Sprague-Dawley (SD) rats. A lumbar posterolateral arthrodesis model was used to test the efficacy of PRP on spinal fusion. Thirty SD rats were divided into three groups by different implants: the PRP group, PRP plus collagen-mineral carrier; the platelet-poor plasma (PPP) group, PPP plus collagen-mineral carrier; and the control group, collagen-mineral only. Spinal fusion was examined using plain radiographs, micro-computed tomography (micro-CT), manual palpation, and histological analysis. The fusion rate by micro-CT and that by manual palpation in groups were compared.

Results

In the micro-CT results, 16 fused segments were observed in the PRP group (80%, 16/20), 2 in the PPP group (10%, 2/20), and 2 in the control group (10%, 2/20). The fusion rate, determined by manual palpation, was 60% (6/10) in the PRP group, 0% (0/10) in the PPP group, and 0% (0/10) in the control group. Histology showed that the PRP group had more new bone and matured marrow formation.

Conclusions

The results of this study demonstrated that PRP on an artificial bone carrier had positive effects on lumbar spinal fusion in rats. In the future, this composite could be potentially used as a bone graft in humans.

Platelet-rich plasma enhances bone union in posterolateral lumbar fusion: A prospective randomized controlled trial

BACKGROUND CONTEXT

Platelet-rich plasma (PRP) accelerates bone union in vivo in a rodent model of spinal fusion surgery. However, PRP's effect on bone union after spinal surgery remains unclear.

PURPOSE

The objective of this study was to evaluate the efficacy of PRP after posterolateral lumbar fusion (PLF) surgery.

STUDY DESIGN/SETTING

Single-center prospective randomized controlled clinical trial with 2-year follow-up.

PATIENT SAMPLE

The patient sample included a total 62 patients (31 patients in the PRP group or 31 patients in the control group).

OUTCOME MEASURES

The outcome measures included the bone fusion rate, the area of bone fusion mass, the duration of bone fusion, and the clinical score using the visual analog scale (VAS).

MATERIALS AND METHODS

We randomized 62 patients who underwent one- or two-level instrumented PLF for lumbar degenerative spondylosis with instability to either the PRP (31 patients) or the control (31 patients) groups. Platelet-rich plasma-treated patients underwent surgery using an autograft bone chip (local bone), and PRP was prepared from patient blood samples immediately before surgery; patients from the control group underwent PLF without PRP treatment. We assessed platelet counts and growth factor concentrations in PRP prepared immediately before surgery. The duration of bone union, the postoperative bone fusion rate, and the area of fusion mass were assessed using plain radiography every 3 months after surgery and by computed tomography at 12 or 24 months. The duration of bone fusion and the clinical scores for low back pain, leg pain, and leg numbness before and 3, 6, 12, and 24 months after surgery were evaluated using VAS.

RESULTS

Data from 50 patients with complete data were included. The bone union rate at the final follow-up was significantly higher in the PRP group (94%) than in the control group (74%) (p=.002). The area of fusion mass was significantly higher in the PRP group (572 mm²) than in the control group (367 mm²) (p=.02). The mean period necessary for union was 7.8 months in the PRP group and 9.8 months in the control group (p=.013). In the PRP, the platelet count was 7.7 times higher and the growth factor concentrations were 50 times higher than those found in plasma (p<.05). There was no significant difference in low back pain, leg pain, and leg numbness in either group at any time evaluated (p>.05).

CONCLUSIONS

Patients treated with PRP showed a higher fusion rate, greater fusion mass, and more rapid bone union after spinal fusion surgery than patients not treated with PRP.

Does Recombinant Human Bone Morphogenic Protein 2 Affect Perioperative Blood Loss after Lumbar and Thoracic Spinal Fusion?

STUDY DESIGN

Retrospective cohort design.

PURPOSE

This study aimed to determine whether recombinant human bone morphogenic protein 2 (rhBMP-2) reduces total perioperative blood loss during lumbar and thoracic fusion.

OVERVIEW OF LITERATURE

Previous studies on rhBMP-2 versus iliac crest bone grafting in thoracic and lumbar fusions have yielded mixed results regarding reductions in blood loss and have largely neglected the postoperative period when analyzing total blood loss. Additionally, these studies have been limited by heterogeneity and sample size.

METHODS

We analyzed the blood loss patterns of 617 consecutive adult patients undergoing lumbar and/or thoracic fusions requiring subfascial drain placement at a single institution from January 2009 to December 2016. Patients were divided into BMP and non-BMP cohorts, and a propensity score analysis was conducted to account for the differences between cohorts.

RESULTS

At a per-level fused basis, the BMP group exhibited a significant reduction in the intraoperative (66.1 mL per-level fused basis; 95% confidence interval [CI], 127.9 to 4.25 mL; p =0.036) and total perioperative blood loss (100.7 mL per-level fused basis; 95% CI, 200.9 to 0.5 mL; p =0.049). However, no significant differences were observed in an analysis when not controlling for the number of levels or when examining the postoperative drain output.

CONCLUSIONS

RhBMP-2 appears to reduce both intraoperative and total blood loss during lumbar and thoracic fusions on a per-level fused basis. This total reduction in blood loss was achieved via intraoperative effects because RhBMP-2 had no significant effect on the postoperative drain output.

Efficacy of Platelet-Rich Plasma for Bone Fusion in Transforaminal Lumbar Interbody Fusion

Study Design

Retrospective case series.

Purpose

To examine the efficacy of platelet-rich plasma (PRP) for bone fusion in transforaminal lumbar interbody fusion (TLIF) using local bone grafting.

Overview of Literature

Several authors have reported the efficacy of PRP for bone union in animal models. However, the use of PRP for bone fusion in TLIF surgery has not been fully explored.

Methods

Twenty patients underwent single-level TLIF surgery because of L4 spondylolisthesis. An interbody fusion cage and local bone were used in nine patients (control group) and an interbody fusion cage, local bone, and PRP were used in 11 patients (PRP group). PRP was prepared from the patients' blood samples (400 mL) immediately before surgery. The duration of bone union and postoperative bone fusion rate were assessed using plain radiography at every 3 months postoperatively and computed tomography at 12 or 24 months postoperatively, respectively. Lower back pain, leg pain, and leg numbness were evaluated using the visual analog scale preoperatively and at 3, 6, 12, and 24 months postoperatively.

Results

The platelet count was 8.7 times higher in PRP than in blood. The bone union rate was significantly superior in the PRP group than in the control group (91% and 77%, respectively; p=0.035), whereas the average duration of bone union was not significantly different between the groups (7.7±0.74 and 10.0±2.00 months, respectively; p=0.131). There was no significant difference in lower back pain, leg pain, and leg numbness in both groups during follow-up (p>0.05).

Conclusions

Our study suggests that the use of PRP in TLIF surgery increases bone fusion rate.

The role of bone marrow aspirate cells in the management of atrophic mandibular fractures by mini-invasive surgical approach: Single-institution experience

PURPOSE

The treatment of fractures involves addressing the biology of fracture repair and the mechanical stability of fracture fixation. Traditionally it has included the addition of bone graft to enhance healing. New advances in the understanding of the cellular and molecular mechanisms of fracture repair have led to the use of growth factors to accelerate bone healing. This study aimed to assess the advantages of autologous stem cell use for atrophic mandibular fracture treatment in comparison to standard technique.

MATERIALS AND METHODS

A total of 35 patients (14 male and 21 female) were treated for fractures of atrophic mandibles between January 2011 and December 2014. Surgical technique provided mini-invasive open reduction with or without immediate homologous bone graft, while selected patients received autologous bone marrow aspirate cell grafts in addition to the standard treatment. Demographic data and details of treatment and outcomes were recorded.

RESULTS

Patients were categorized according to the use of autologous stem cells, leaving 17 patients treated with standard technique and autologous stem cells (Group A) and 18 treated with standard osteosynthesis only (Group B). Of the 35 patients, 26 had bilateral fractures; most patients had significant medical co-morbidities. Immediate bone graft was used in 37.1% of patients (7 in group A and 6 in group B). Complications occurred in 5 patients (14.3%). Two patients in group B (11.1%) showed non-union of the fracture. One patient in group A (5.8%) and one patient in group B (5.5%) showed wound dehiscence and were treated conservatively; one patient in group B had a local infection (5.5%), one out of 35 (2.8%), that was managed by prolonged antibiotic treatment.

CONCLUSIONS

Despite the advanced age and medical co-morbidities of the vast majority of patients, mini-invasive open approach with autologous bone graft ensures a fast and excellent recovery. Moreover, the management of atrophic mandibular fractures by bone marrow aspirate cells is a safe and useful procedure which has a lower complication rate when compared to standard technique.

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.

Platelet-Rich Plasma: The Choice of Activation Method Affects the Release of Bioactive Molecules

Platelet-Rich Plasma (PRP) is a low-cost procedure to deliver high concentrations of autologous growth factors (GFs). Platelet activation is a crucial step that might influence the availability of bioactive molecules and therefore tissue healing. Activation of PRP from ten voluntary healthy males was performed by adding 10% of CaCl₂, 10% of autologous thrombin, 10% of a mixture of CaCl₂ + thrombin, and 10% of collagen type I. Blood derivatives were incubated for 15 and 30 minutes and 1, 2, and 24 hours and samples were evaluated for the release of VEGF, TGF-β1, PDGF-AB, IL-1β, and TNF-α. PRP activated with CaCl₂, thrombin, and CaCl₂/thrombin formed clots detected from the 15-minute evaluation, whereas in collagen-type-I-activated samples no clot formation was noticed. Collagen type I produced an overall lower GF release. Thrombin, CaCl₂/thrombin, and collagen type I activated PRPs showed an immediate release of PDGF and TGF-β₁ that remained stable over time, whereas VEGF showed an increasing trend from 15 minutes up to 24 hours. CaCl₂ induced a progressive release of GFs from 15 minutes and increasing up to 24 hours. The method chosen to activate PRP influences both its physical form and the releasate in terms of GF amount and release kinetic.

Application of calcium phosphates and fibronectin as complementary treatment for osteoporotic bone fractures

INTRODUCTION

The gradual aging of the population results in increased incidence of osteoporotic bone fractures. In a good quality bone, the fixation with the usual methods is adequate, but not in osteoporotic bone, in which consolidation delays and other complications are common, with failure rates for screws up to 25%.

OBJECTIVE

To test fibronectin loaded hydroxyapatite as a complementary treatment for osteoporotic fractures.

MATERIAL AND METHODS

This study was performed in a vivo model; 42 female osteoporotic adult rabbits 4-5kg (White New Zealand) were used. Two groups (hydroxyapatite and fibronectin loaded hydroxyapatite) and a control group were tested. 3 time points 24h, 48h and 5days were studied. Defects were created in both femurs, in one of them, a cannulated screw (4mm) and a biocompatible material were placed; in the other femur a screw was inserted without supplemented material forming the control group. Osteoporosis was induced from models already known throughout administration of steroids. Samples were analyzed histologically and through imaging (micro Ct).

RESULTS

Basal levels of BMD are observed below to normal when compared to other studies (0.25/0.3 instead of 0.4). Global and dependent of time analysis of samples, show no significant differences for samples analyzed. However, an important trend was noted for variables that define the trabecular bone microarchitecture. Indices that define trabecular microarchitecture in the comparative analysis found to have statistical differences (p<0.01).

DISCUSSION

Osteosynthesis in an osteoporotic bone is a challenge for the surgeon, due to a reduced bone mineral density and different bone architecture. The main finding was the verification of the hypothesis that the trabecular bone parameters increases with our augmentation material in weak rabbit bone quality. Also, the histological analyses of samples show an increase of non inflammatory cells in protein samples (OHAp-Fn) from the first 24hours.

CONCLUSION

An early response of rabbit osteroporotic bone to a complementary treatment with fibronectin loaded hydroxyapatite has been observed. This response is reflected in greater values for indices that define the trabecular bone microarchitecture, thickness and separation, a greater non-inflammatory cellularity after only 24hours and an increased amount of connective tissue observed at 48hours.

The Role of Platelet and its Interaction with Aspirin

<p>Introduction. Platelets are not strictly “cells”, they are cytoplasmic fragments that are produced by the division of the cytoplasm of the megakaryocytes in the bone marrow; among its properties of adhesion and aggregation, platelets are involved in primary hemostasis, thrombosis, repair and tissue regeneration processes. To modify the pro-thrombotic platelet properties aspirin (ASA) is provided, which allows blocking the synthesis of prostaglandins in order to irreversibly inhibit the COX1 and prevent platelet aggregation. The current guidelines govern the use of aspirin in the prevention of cardiovascular diseases. Objective. In this review paper graphics were created to facilitate the understanding of platelets and its interaction with various physiological and pathological processes. Methodology. A literature review of a total of 74 documents such as articles and books was carried out; it was obtained from bibliographic searches in the following databases: Scielo, NEJM, Elsevier, Pubmed, Redalyc, Wiley, Springer, ScienceDirect, BVS, Nature Riviews, EBSCO, Naxos (databases offered by the University of Cauca). Mendeley free access program was used for the management and organization of information. Conclusion. It is recognized the role of platelet in different physiopathological processes and thus its interaction with aspirin, preventing its aggregation and thrombus formation in the spleen and other organs, this way contributing to the prevention of future cardiovascular events.</p>

Bone Marrow Concentrate Improves Early Cartilage Phase Maturation of a Scaffold Plug in the Knee: A Comparative Magnetic Resonance Imaging Analysis to Platelet-Rich Plasma and Control

BACKGROUND

Limited information exists on the clinical use of a synthetic osteochondral scaffold plug for cartilage restoration in the knee.

PURPOSE/HYPOTHESIS

The purpose of this study was to compare the early magnetic resonance imaging (MRI) appearance, including quantitative T2 values, between cartilage defects treated with a scaffold versus a scaffold with platelet-rich plasma (PRP) or bone marrow aspirate concentrate (BMAC). The hypothesis was that the addition of PRP or BMAC would result in an improved cartilage appearance.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Forty-six patients with full-thickness cartilage defects of the femur were surgically treated with a control scaffold (n = 11), scaffold with PRP (n = 23), or scaffold with BMAC (n = 12) and were followed prospectively. Patients underwent MRI with a qualitative assessment and quantitative T2 mapping at 12 months after surgery. An image assessment was performed retrospectively by a blinded musculoskeletal radiologist. The cartilage phase was measured by cartilage fill and quantitative T2 values on MRI. A comparison between groups after cartilage repair was performed.

RESULTS

The control scaffold group consisted of 8 male and 3 female patients (mean age, 38 years; mean body mass index [BMI], 25 kg/m(2)), the PRP group had 15 male and 8 female patients (mean age, 39 years; mean BMI, 26 kg/m(2)), and the BMAC group consisted of 8 male and 4 female patients (mean age, 36 years; mean BMI, 26 kg/m(2)). The PRP-treated (P = .002) and BMAC-treated (P = .03) scaffolds had superior cartilage fill compared with the control group. With quantitative methods, the PRP group demonstrated a mean T2 value (49.1 ms) that was similar to that of the control scaffold group (42.7 ms; P = .07), but the BMAC group demonstrated a mean T2 value (60.5 ms) closer to that of superficial hyaline cartilage (P = .01). The stratification of T2 values between the deep and superficial zones was not observed in any of the groups.

CONCLUSION

In this comparative study, patients treated with scaffold implantation augmented with BMAC had improved cartilage maturation with greater fill and mean T2 values closer to that of superficial native hyaline cartilage at 12 months. Further work will determine if this translates into improved clinical outcomes.

Platelet concentrates in spine fusion: meta-analysis of union rates and complications in controlled trials

PURPOSE

Platelet concentrates in spine fusion gained increasing popularity among spine surgeons. They avoid morbidity of bone harvest and promise good union rates without additional device-related adverse events. Therefore, they seem to be a safe and effective alternative to common bone substitutes. This meta-analysis assesses the available evidence for union rate and overall complications with the use of platelet concentrates in spine fusion.

METHODS

We conducted an online search for relevant controlled trials and extracted data on union rates, complications, and revision rates. These data were synthesized in a meta-analysis using fixed-effects odds ratios (OR). To assess covariates, meta-regression was performed as well.

RESULTS

Our search produced 166 results, ten of which were eligible for inclusion. These studies report on a total of 763 patients (328 experimental, 435 controls) with a mean age of 50.3 ± 7.5 years. Mean follow-up was 1.9 ± 0.0.4 years. With the use of platelet concentrates, union rate decreased significantly, OR 0.53 (95 % CI 0.35-0.79, p = 0.002), compared with the control group. There was no statistically significant difference in complication rates OR 1.34 (95 % CI 0.62-2.90, p = 0.46) or in revision rates OR 3.0 (95 % CI 0.90-10.00, p = 0.74). Meta-regression showed no statistically significant influence of randomization, Jadad score, or assessment of fusion.

CONCLUSION

The use of platelet concentrates in spine fusion shows significantly decreased union rates compared with the control group. However, complication and revision rates were not significantly increased. The current data do not recommend the use of platelet concentrate in spine fusion.

Biologic adjuvants and bone: current use in orthopedic surgery

Normal bone healing is a complex process that eventually restores original structure and function to the site of trauma. However, clinical circumstances such as nonunion, critical-sized defects, systemic bone disease, and fusion procedures have stimulated a search for ways to enhance this normal healing process. Biologics are an important part of this search and many, including bone marrow aspirate concentrate, demineralized bone matrix, platelet-rich plasma, bone morphogenic proteins, and platelet-derived growth factor, are currently in clinical use. Many others, including mesenchymal stem cells, parathyroid hormone, and Nel-like molecule-1 (NELL-1) will likely be in use in the future depending on the results of preclinical and clinical trials.

A systematic assessment of the use of platelet-rich plasma in spinal fusion

Spinal fusion is one of the most commonly performed procedures for the treatment of spinal instability caused by a multitude of pathologies. However, despite significant advances in spinal instrumentation, failed fusion, or pseudoarthrosis, remains a significant challenge. Therefore, other additives such as bone graft extenders and growth factors have been explored as a method to augment fusion rates. Platelet-rich plasma (PRP) represents an additional approach, as it has shown some promise in bone regeneration. While the general use of PRP in orthopedic applications has been reviewed previously, its use in spinal fusion has not been systematically analyzed. The objective of this review is to systematically discuss the role of PRP in augmentation of bone regeneration for the purpose of spinal fusion. Background information on PRP, including a discussion of its preparation, activation, and growth factors, is included. Additionally, data from in vitro studies utilizing PRP in bone tissue engineering strategies is analyzed, and the available animal and clinical studies are systematically reviewed in order to provide guidance on future research pathways as well as the potential role of PRP in spinal fusion surgery.

Large volume inside the cage leading incomplete interbody bone fusion and residual back pain after posterior lumbar interbody fusion

The purpose of this study is to compare intervertebral bone fusion and clinical outcomes in L4-5 posterior lumbar interbody fusion (PLIF) using the same posterior instrumentation with four combinations of one of three types of interbody cage with one of two bone grafts, iliac and local or only local. In 67 patients who underwent L4-5 PLIF, 19 patients had the Brantigan cage and iliac and local bone graft, 18 with the TELAMON C cage and iliac and local bone graft, 16 with the TELAMON C cage and local bone graft (TL), and 14 with the OIC PEEK cage and local bone graft. Clinical assessments were based on Japanese Orthopaedic Association (JOA) scores and on the visual analogue scale (VAS). The bone fusion assessments were based on radiography and CT scans according to the Brantigan, Steffee, and Fraser criteria. More than 2 years after surgery, these assessments were made. In the results, the fusion outcome for the group receiving TL was significantly less than those for the other three groups. In TL, multivariate logistic regression analysis showed that the inside volume of the cage of ≥2.0 mL was the only significant factor for incomplete fusion. Moreover, the VAS (low back pain) score was significantly higher for TL than for the other three groups. In conclusions, we believe that the large volume inside the cage (≥2.0 mL) with local bone graft may lead incomplete interbody bone fusion and residual postsurgical low back pain after PLIF.

Transforming growth factor Beta family: insight into the role of growth factors in regulation of fracture healing biology and potential clinical applications

The transforming growth factor beta (TGF-β) family forms a group of three isoforms, TGF-β1, TGF-β2, and TGF-β3, with their structure formed by interrelated dimeric polypeptide chains. Pleiotropic and redundant functions of the TGF-β family concern control of numerous aspects and effects of cell functions, including proliferation, differentiation, and migration, in all tissues of the human body. Amongst many cytokines and growth factors, the TGF-β family is considered a group playing one of numerous key roles in control of physiological phenomena concerning maintenance of metabolic homeostasis in the bone tissue. By breaking the continuity of bone tissue, a spread-over-time and complex bone healing process is initiated, considered a recapitulation of embryonic intracartilaginous ossification. This process is a cascade of local and systemic phenomena spread over time, involving whole cell lineages and various cytokines and growth factors. Numerous in vivo and in vitro studies in various models analysing cytokines and growth factors' involvement have shown that TGF-β has a leading role in the fracture healing process. This paper sums up current knowledge on the basis of available literature concerning the role of the TGF-β family in the fracture healing process.

Ceramic-based bone grafts as a bone grafts extender for lumbar spine arthrodesis: a systematic review

Study Design Systematic review. Objective Ceramic-based bone grafts have been widely utilized to reduce the need for iliac crest bone grafting given the complications associated with the harvest of iliac crest autograft. As a family, ceramics vary widely based on differences in composition, manufacturing, porosity, and structure, which may ultimately affect their efficacy. This article reviews the current data of ceramics used in different environments in the lumbar spine to achieve arthrodesis. Methods Medline, EMBASE, and Cochrane Central Register of Controlled Trials were searched for publications from 1980 to 2013 involving ceramic-based bone grafts in the lumbar spine. Variables such as age of patients, volume of ceramic, procedure, time to evaluation, method of evaluation, specific composition of ceramic, adjuncts used with ceramic products, type of fusion, and fusion rate were compared using a multivariate logistic regression model. Results Thirty studies with 1,332 patients met the final inclusion criteria. The overall fusion rate for all ceramic products as a bone graft extender in the lumbar spine was 86.4%. Age, gender, method of evaluation (plain radiographs, computed tomography, or combination), or specific ceramic product did not significantly affect fusion rate. Ceramics used in combination with local autograft resulted in significantly higher fusion rates compared with all other adjuncts, and bone marrow aspirate and platelet concentrates resulted in significantly lower fusion rates. Conclusions Ceramic-based bone grafts represent a promising bone graft extender in lumbar spine fusion when an osteoinductive stimulus, such as local bone graft is available.

Use of platelet rich plasma for the treatment of bicipital tendinopathy in spinal cord injury:: a pilot study

The purpose of study is to explore the efficacy and safety of platelet rich plasma (PRP) in the nonoperative management of shoulder tendinopathy amongst individuals with spinal cord injury. This objective was met by completing a pilot study on the effectiveness and safety of a PRP injection into the biceps tendon demonstrating clinical and ultrasonagraphic pathology. Recent analysis of the preliminary pilot data has demonstrated remarkably convincing results demonstrating both the safety and efficacy of this novel intervention.

Stem cell-based therapy for prevention of delayed fracture union: a randomized and prospective preliminary study

Distal tibial fractures tend towards delayed- or nonunion. The purpose of this study was to evaluate the safety and efficacy of early minimally invasive intervention (MII) in the treatment of these fractures. A total 24 consecutive patients who underwent operative treatment for distal tibial fractures were randomized into a control and an intervention group. MII entailed aspirating iliac crest bone marrow and peripheral blood, yielding mesenchymal stem cells (MSCs) and platelet-rich plasma (PRP) respectively, that were mixed with demineralized bone matrix (DBM) and injected under fluoroscopic control into the fracture site. No complications occurred in either group. The median time to union was 1.5 months in the MII group and 3 months in the control group. MII was found to be a safe and efficient procedure.

Bone ingrowth and vascular supply in experimental spinal fusion with platelet-rich plasma

STUDY DESIGN

Prospective investigation using a posterolateral spinal fusion (PLSF) model in rabbits.

OBJECTIVE

To assess the effects of platelet-rich plasma (PRP) alone, or with uncultured bone marrow, on bone ingrowth and angiogenesis in experimental PLSF.

SUMMARY OF BACKGROUND DATA

PRP is an autologous substance potentially beneficial to spinal fusion, because it includes several growth factors that may stimulate bone ingrowth and angiogenesis. However, the results of experimental and clinical investigations on the effectiveness of PRP in spinal fusion are controversial. This study was aimed at analyzing the influence of PRP on bone ingrowth and angiogenesis in experimental PLSF.

METHODS

Twenty White New Zealand rabbits underwent PLSF at L4-L5 level. The graft material included a ceramic carrier (Pro-Osteon 500R) loaded, in 7 rabbits, with PRP alone on the right side (group 1A) and with uncultured bone marrow in the left side (group 1B). In 7 rabbits, the ceramic carrier was used alone in the right side (group 2A), and with uncultured bone marrow in the left side (group 2B). Six rabbits (group 3) were sham operated on both right and left sides. Six months after surgery, the lumbar spine was harvested en bloc and evaluated by high-resolution radiographs (Faxitron, Wheeling, IL) and histology.

RESULTS

The radiographical outcome showed a fusion rate of 86% in groups 1A, 1B, and 2B and a fusion rate of 71% in group 2A. No specimen showed a solid fusion in the sham group. Histological analysis revealed new bone formation in the periapophyseal area in groups 1 and 2, but a complete bony bridge between the transverse processes was not observed in any specimen. In all groups, vascular density was significantly greater in the peri- compared with the interapophyseal region. In the PRP group, there was no evidence of increased vascular density in the grafted material compared with the other groups.

CONCLUSION

In experimental PLSF model in rabbits, PRP was not effective in promoting new bone formation and vascularization.

A systematic review of comparative studies on bone graft alternatives for common spine fusion procedures

BACKGROUND

The increased prevalence of spinal fusion surgery has created an industry focus on bone graft alternatives. While autologous bone graft remains the gold standard, the complications and morbidity from harvesting autologous bone drives the search for reliable and safe bone graft substitutes. With the recent information about the adverse events related to bone morhogenetic protein use, it is appropriate to review the literature about the numerous products that are not solely bone morphogenetic protein.

PURPOSE

The purpose of this literature review is to determine the recommendations for use of non-bone morphogenetic protein bone graft alternatives in the most common spine procedures based on a quantifiable grading system.

STUDY DESIGN

Systematic literature review.

METHODS

A literature search of MEDLINE (1946-2012), CINAHL (1937-2012), and the Cochrane Central Register of Controlled Trials (1940-April 2012) was performed, and this was supplemented by a hand search. The studies were then evaluated based on the Guyatt criteria for quality of the research to determine the strength of the recommendation.

RESULTS

In this review, more than one hundred various studies on the ability of bone graft substitutes to create solid fusions and good patient outcomes are detailed.

CONCLUSION

The recommendations for use of bone graft substitutes and bone graft extenders are based on the strength of the studies and given a grade.

Gelatin gel as a carrier of platelet-derived growth factors

Currently, patient’s own growth factors from platelet-rich plasma and platelet-rich fibrin have been clinically used for repair and regeneration of defective tissues. In platelet-rich plasma and platelet-rich fibrin, fibrin gel is formed from blood fibrinogen and functions as a carrier for growth factors. In this study, the growth factors were extracted from the platelet-rich fibrin and incorporated into a gelatin gel by mixing the platelet-rich fibrin extract and gelatin solution before cross-linking with glutaraldehyde. About 70% of TGF-β1 was found to be released in vitro from the gelatin gel containing the platelet-rich fibrin extract into phosphate-buffered saline (–) in 7 days. The gelatin gel containing basic fibroblast growth factor, prepared as a comparison, showed a similar release profile. The gelatin gels were slowly degraded with time after subcutaneous implantation on the back of rats, and the gel containing the platelet-rich fibrin extract strongly induced neovascularization and granulation tissue formation around the implantation site compared to the gel only and the gel containing basic fibroblast growth factor, platelet-rich plasma, or platelet-rich fibrin. The gelatin gel containing the platelet-rich fibrin extract was attempted as wound dressing on a full-thickness skin defect model. After 2 weeks of application, the gel was found to be more effective in acceleration of wound healing than the commonly used platelet-rich plasma.

Improving the clinical evidence of bone graft substitute technology in lumbar spine surgery

Bone graft substitutes have been used routinely for spine fusion for decades, yet clinical evidence establishing comparative data remains sparse. With recent scrutiny paid to the outcomes, complications, and costs associated with osteobiologics, a need to improve available data guiding efficacious use exists. We review the currently available clinical literature, studying the outcomes of various biologics in posterolateral lumbar spine fusion, and establish the need for a multicenter, independent osteobiologics registry.

Platelet-rich plasma combined with hydroxyapatite for lumbar interbody fusion promoted bone formation and decreased an inflammatory pain neuropeptide in rats

STUDY DESIGN

A prospective interventional trial, using a rat model of lumbar interbody fusion.

OBJECTIVE

To examine the potential efficacy of platelet-rich plasma (PRP) for lumbar interbody fusion, using hydroxyapatite (HA).

SUMMARY OF BACKGROUND DATA

PRP is an autologous product containing a high concentration of platelets in a small volume of plasma and has osteoinductive effects. HA has osteoconductive ability and has been used in combination with autogenous bone for spine fusion. However, reports using PRP with HA for spine fusion are very few. The purpose of this study was to examine the efficacy of PRP with HA for spinal interbody fusion and at the same time to estimate the change in immunoreactivity of the inflammatory neuropeptide, calcitonin gene-related peptide (CGRP), in dorsal root ganglion (DRG) neurons innervating spinal discs.

METHODS

A total of 35 Sprague-Dawley rats were used in this study. Twenty-one rats were used for conducting interbody fusion experiments, 7 rats were used as immunostaining controls, and 7 other rats were used as blood donors for making PRP. L5-L6 interbody fusion was performed on 21 rats using HA + PRP (n = 7), HA + platelet-poor plasma (n = 7), or HA + saline (n = 7). Simultaneously, Fluoro-Gold neurotracer was applied to the intervertebral space to detect DRG neurons innervating the discs. L5-L6 lumbar radiographs were obtained and lumbar DRGs were immunostained for CGRP. The rate of bone union and the change in CGRP immunoreactive DRG neurons innervating the discs were evaluated and compared among groups.

RESULTS

All L5-L6 lumbar discs were fused in the PRP + HA group (fused 7/total 7), whereas only 1 case was fused in the platelet-poor plasma group (1 of 7) and no cases in the HA-only group (0 of 7), which was a significant difference. Upon immunohistochemical analysis, CGRP-positive neurons innervated L5-L6 intervertebral discs in nonunion cases, and these were significantly increased compared with those in union cases.

CONCLUSION

Our study suggests that using PRP with HA was beneficial for spine fusion. This combination may promote bone union and also decrease inflammatory neuropeptide in sensory neurons innervating the discs.

Intra-operatively customized implant coating strategies for local and controlled drug delivery to bone

Bone is one of the few tissues in the human body with high endogenous healing capacity. However, failure of the healing process presents a significant clinical challenge; it is a tremendous burden for the individual and has related health and economic consequences. To overcome such healing deficits, various concepts for a local drug delivery to bone have been developed during the last decades. However, in many cases these concepts do not meet the specific requirements of either surgeons who must use these strategies or individual patients who might benefit from them. We describe currently available methods for local drug delivery and their limitations in therapy. Various solutions for drug delivery to bone focusing on clinical applications and intra-operative constraints are discussed and drug delivery by implant coating is highlighted. Finally, a new set of design and performance requirements for intra-operatively customized implant coatings for controlled drug delivery is proposed. In the future, these requirements may improve approaches for local and intra-operative treatment of patients.

Proliferation and differentiation of human tenocytes in response to platelet rich plasma: an in vitro and in vivo study

Platelet rich plasma (PRP) is the autologous plasma fraction with a platelet-rich cellular component which is enriched with a number of growth factors. Due to its availability and low cost, PRP has become an increasingly popular clinical tool as an alternative source of growth factors for various applications, for example, tendon regeneration but with limited success in clinical trials. The main objective of the current study was to determine whether activated PRP [i.e., platelet rich plasma-clot release (PRCR)] could be used to induce the proliferation and collagen synthesis in human tenocyte in vitro. The advantage of using PRCR is that the platelet-derived bioactive factors are more concentrated and could initiate a more rapid and accelerated healing response than PRP. Our results demonstrated that 10% PRCR treatment accelerated the extent of cell proliferation and collagen production by human tenocytes in vitro. The expression of specific tenocyte markers were similar to conventional fetal bovine serum (FBS)-treated tenocytes implanted in mice within 14 days of implantation in diffusion chambers. Moreover, relatively more collagen fibrils were evident in PRCR-treated tenocytes in vivo as compared to 10% FBS-treated cells. Overall, our feasibility study has indicated that PRCR can induce human tenocyte proliferation and collagen synthesis which could be implemented for future tendon regeneration in reconstructive surgeries.