Healos graft carrier with bone marrow aspirate instead of allograft as adjunct to local autograft for posterolateral fusion in degenerative lumbar scoliosis: a minimum 2-year follow-up study

A comprehensive systematic review of marketed bone grafts for load-bearing critical-sized bone defects

Treatment of critical-sized bone defects typically involves implantation of a bone graft. Various types of bone grafts are nowadays marketed, categorized by their origin as allografts, xenografts, or synthetic grafts. Despite their widespread use, a comprehensive understanding of their morphology and mechanical response remains elusive. Controlling these characteristics for promoting bone growth and ensuring mechanical resistance remains challenging, especially in load-bearing districts. This study aims to systematically review existing literature to delineate the principal morpho-mechanical characteristics of marketed bone grafts designed for load-bearing applications. Furthermore, the obtained data are organized and deeply discussed to find out the relationship between different graft characteristics. Among 196 documents identified through PRISMA guidelines, encompassing scientific papers and 510(k) documents, it was observed that a majority of marketed bone grafts exhibited porosity akin to bone (>60%) and mechanical properties resembling those of low-bone volume fraction trabecular bone. The present review underscores the dearth of information regarding the morpho-mechanical characteristics of bone grafts and the incomparability of data derived from different studies, due to the absence of suitable standards and guidelines. The need for new standards and complete and transparent morpho-mechanical characterization of marketed bone grafts is finally emphasized. Such an approach would enhance the comparability of data, aiding surgeons in selecting the optimal device to meet patient's needs.

Use of Autologous Stem Cells in Lumbar Spinal Fusion: A Systematic Review of Current Clinical Evidence

STUDY DESIGN

Systematic review.

OBJECTIVES

To systematically review, critically appraise and synthesize evidence on use of autologous stem cells sources for fusion in the lumbar spine.

METHODS

A systematic search of PubMed/MEDLINE, EMBASE and ClinicalTrials.gov through February 20, 2020 was conducted comparing autologous cell grafts to other biologics for lumbar spine fusion. The focus was on studies comparing distinct patient groups.

RESULTS

From 343 potentially relevant citations, 15 studies met the inclusion criteria set a priori. Seven studies compared distinct patient groups, with BMA being used in combination with allograft or autograft not as a standalone material. No economic evaluations were identified. Most observational studies were at moderately high risk of bias. When used for primary lumbar fusion, no statistical differences in outcomes or complications were seen between BMA+autograft/or +allograft compared to autograft/allograft alone. Compared with allograft, data from a RCT suggested statistically better fusion and lower complication rates with concentrated BMA+allograft. When used in revisions, no differences in outcomes were seen between BMA+allograft and either autograft or rh-BMP-2 but fusion rates were lower with BMA+allograft, leading to additional revision surgery.

CONCLUSIONS

There was substantial heterogeneity across studies in patient populations, sample size, biologic combinations, and surgical characteristics making direct comparisons difficult. The overall quality of evidence for fusion rates and the safety of BMA in lumbar fusion procedures was considered very low, with studies being at moderately high or high risk of bias.

Synthetic Bone Graft Materials in Spine Fusion: Current Evidence and Future Trends

Historically, iliac crest bone autograft has been considered the gold standard bone graft substitute for spinal fusion. However, the significant morbidity associated with harvesting procedures has influenced decision-making and practice patterns. To minimize these side effects, many clinicians have pursued the use of bone graft extenders to minimize the amount of autograft required for fusion in certain applications. Synthetic materials, including a variety of ceramic compounds, are a class that has been studied extensively as bone graft extenders. These have been used in combination with a wide array of other biomaterials and investigated in a variety of different spine fusion procedures. This review will summarize the current evidence of different synthetic materials in various spinal fusion procedures and discuss the future of novel synthetics.

Bone regeneration in Ds-Red pig calvarial defect using allogenic transplantation of EGFP-pMSCs - A comparison of host cells and seeding cells in the scaffold

Background

Cells, scaffolds, and factors are the triad of regenerative engineering; however, it is difficult to distinguish whether cells in the regenerative construct are from the seeded cells or host cells via the host blood supply. We performed a novel in vivo study to transplant enhanced green fluorescent pig mesenchymal stem cells (EGFP-pMSCs) into calvarial defect of DsRed pigs. The cell distribution and proportion were distinguished by the different fluorescent colors through the whole regenerative period.

Method/Results

Eight adult domestic Ds-Red pigs were treated with five modalities: empty defects without scaffold (group 1); defects filled only with scaffold (group 2); defects filled with osteoinduction medium-loaded scaffold (group 3); defects filled with 5 x 10³ cells/scaffold (group 4); and defects filled with 5 x 10⁴ cells/scaffold (group 5). The in vitro cell distribution, morphology, osteogenic differentiation, and fluorescence images of groups 4 and 5 were analyzed. Two animals were sacrificed at 1, 2, 3, and 4 weeks after transplantation. The in vivo fluorescence imaging and quantification data showed that EGFP-pMSCs were represented in the scaffolds in groups 4 and 5 throughout the whole regenerative period. A higher seeded cell density resulted in more sustained seeded cells in bone regeneration compared to a lower seeded cell density. Host cells were recruited by seeded cells if enough space was available in the scaffold. Host cells in groups 1 to 3 did not change from the 1st week to 4th week, which indicates that the scaffold without seeded cells cannot recruit host cells even when enough space is available for cell ingrowth. The histological and immunohistochemical data showed that more cells were involved in osteogenesis in scaffolds with seeded cells.

Conclusion

Our in vivo results showed that more seeded cells recruit more host cells and that both cell types participate in osteogenesis. These results suggest that scaffolds without seeded cells may not be effective in bone transplantation.

An inception cohort study of patients in a military clinic treated for lower back pain with lumbar fusion and SIGNAFUSE® with a systematic review of the literature

Background: Use of synthetic bone graft substitutes for spinal fusion has increased sharply over the past 20 years. SIGNAFUSE® is one such synthetic graft material that provides an osteostimulatory effect for spinal fusion. Because clinical trials are not required for commercialization of synthetic bone graft substitutes in the United States, fusion rates attained using SIGNAFUSE for lumbar fusion are not well documented. The goal of the current study is to determine the rate of spinal fusion in a military clinic following lumbar fusion surgery augmented with SIGNAFUSE. Methods: We report a retrospective chart review of 8 patients who received lumbar spinal fusion surgery augmented with SIGNAFUSE. All patients were assessed by computed tomographic (CT) imaging at least 1-year post-surgery to determine whether bony fusion had occurred. We also systematically reviewed literature sources that report fusion rate following spinal fusion surgery, for broader context. Results: An average of 1.6 spinal levels were treated with SIGNAFUSE-loaded interbody cages. All patients had stabilization hardware via pedicle screws or integrated cage fixation. Seven of 8 patients successfully fused, for an overall fusion rate of 87.5% (95% confidence interval: 47.4% to 99.7%). Systematic review of 26 recent publications that included 1,126 patients treated with synthetic bone graft showed that the overall fusion rate in the literature is 84.4%. Conclusions: Fusion was achieved in 87.5% of patients treated with SIGNAFUSE. This is comparable to the fusion rate in a systematic review of 1,126 patients treated with synthetic bone graft materials.

Allograft Versus Demineralized Bone Matrix in Instrumented and Noninstrumented Lumbar Fusion: A Systematic Review

STUDY DESIGN

Systematic review.

OBJECTIVES

The aim was to determine the fusion efficacy of allograft and demineralized bone matrix (DBM) in lumbar instrumented and noninstrumented fusion procedures for degenerative lumbar disorders.

METHODS

A literature search was conducted using the PubMed and Cochrane databases. To be considered, publications had to meet 4 criteria: patients were treated for a degenerative lumbar disorder, a minimum group size of 10 patients, use of allograft or DBM, and at least a 2-year follow-up. Data on the study population, follow-up time, surgery type, grafting material, fusion rates, and its definition were collected.

RESULTS

The search yielded 692 citations with 17 studies meeting the criteria including 4 retrospective and 13 prospective studies. Six studies used DBM and 11 employed allograft alone or in the combination with autograft. For the allograft, fusion rates ranged from 58% to 68% for noninstrumented and from 68% to 98% for instrumented procedures. For DBM, fusion rates were 83% for noninstrumented and between 60% and 100% for instrumented lumbar fusion procedures.

CONCLUSIONS

Both allograft and DBM appeared to provide similar fusion rates in instrumented fusions. On the other hand, in noninstrumented procedures DBM was superior. However, a large variation in the type of surgery, outcomes collection, lack of control groups, and follow-up time prevented any significant conclusions. Thus, studies comparing the performance of allograft and DBM to adequate controls in large, well-defined patient populations and with a sufficient follow-up time are needed to establish the efficacy of these materials as adjuncts to fusion.

Comparison of the PEEK cage and an autologous cage made from the lumbar spinous process and laminae in posterior lumbar interbody fusion

Background

A prospective cohort study was performed to evaluate the clinical and radiological outcomes following posterior lumbar interbody fusion (PLIF) in patients treated with a PEEK cage compared to those treated with an autologous cage using the lumbar spinous process and laminae (ACSP).

Methods

Sixty-nine consecutive patients with lumbar degenerative disc disease were randomly assigned to either a PEEK cage (group A, n = 34) or an ACSP (group B, n = 35). Monosegmental PLIF was performed in all patients. Mean lumbar lordosis, mean disc height, visual analog scale (VAS) scores, functional outcomes, fusion rates and complication rates were recorded and compared. The patients were followed postoperatively for a minimum of 2 years.

Results

Successful radiographic fusion was documented in all patients. No flexion–extension hypermobility or pedicle screw loosening or breakage occurred during the follow-up period. No significant difference existed between the 2 groups when comparing the mean lumbar lordosis, mean disc height, visual analog scale (VAS) scores, functional outcomes, fusion rates or complication rates. Overall satisfactory results were achieved in both groups.

Conclusions

The results suggest that the ACSP appears to be equally as safe and effective as the PEEK cage.

Trial registration

ISRCTN25558534. Retrospectively registered 16/02/2016.

Synthetic bone graft versus autograft or allograft for spinal fusion: a systematic review

The purpose of this review was to compare the efficacy and safety of synthetic bone graft substitutes versus autograft or allograft for the treatment of lumbar and cervical spinal degenerative diseases. Multiple major medical reference databases were searched for studies that evaluated spinal fusion using synthetic bone graft substitutes (either alone or with an autograft or allograft) compared with autograft and allograft. Randomized controlled trials (RCT) and cohort studies with more than 10 patients were included. Radiographic fusion, patient-reported outcomes, and functional outcomes were the primary outcomes of interest. The search yielded 214 citations with 27 studies that met the inclusion criteria. For the patients with lumbar spinal degenerative disease, data from 19 comparative studies were included: 3 RCTs, 12 prospective, and 4 retrospective studies. Hydroxyapatite (HA), HA+collagen, β-tricalcium phosphate (β-TCP), calcium sulfate, or polymethylmethacrylate (PMMA) were used. Overall, there were no differences between the treatment groups in terms of fusion, functional outcomes, or complications, except in 1 study that found higher rates of HA graft absorption. For the patients with cervical degenerative conditions, data from 8 comparative studies were included: 4 RCTs and 4 cohort studies (1 prospective and 3 retrospective studies). Synthetic grafts included HA, β-TCP/HA, PMMA, and biocompatible osteoconductive polymer (BOP). The PMMA and BOP grafts led to lower fusion rates, and PMMA, HA, and BOP had greater risks of graft fragmentation, settling, and instrumentation problems compared with iliac crest bone graft. The overall quality of evidence evaluating the potential use and superiority of the synthetic biological materials for lumbar and cervical fusion in this systematic review was low or insufficient, largely due to the high potential for bias and small sample sizes. Thus, definitive conclusions or recommendations regarding the use of these synthetic materials should be made cautiously and within the context of the limitations of the evidence.

A Comprehensive Review of Complication Rates After Surgery for Adult Deformity: A Reference for Informed Consent

OBJECTIVE

An up-to-date review of recent literatures and a comprehensive reference for informed consent specific to ASD complications is lacking. The goal of the present study was to determine current complication rates after ASD surgery, in order to provide a reference for informed consent as well as to determine differences between three-column and non-three-column osteotomy procedures to aid in shared decision making.

METHODS

A review of the literature was conducted using the PubMed database. Randomized controlled trials, nonrandomized trials, cohort studies, case-control studies, and case series providing postoperative complications published in 2000 or later were included. Complication rates were recorded and calculated for perioperative (both major and minor) and long-term complication rates. Postoperative outcomes were all stratified by surgical procedure (ie, three-column osteotomy and non-three-column osteotomy).

RESULTS

Ninety-three articles were ultimately eligible for analysis. The data of 11,692 patients were extracted; there were 3,646 complications, mean age at surgery was 53.3 years (range: 25-77 years), mean follow-up was 3.49 years (range: 6 weeks-9.7 years), estimated blood loss was 2,161 mL (range: 717-7,034 mL), and the overall mean complication rate was 55%. Specifically, major perioperative complications occurred at a mean rate of 18.5%, minor perioperative complications occurred at a mean rate of 15.7%, and long-term complications occurred at a mean rate of 20.5%. Furthermore, three-column osteotomy resulted in a higher overall complication rate and estimated blood loss than non-three-column osteotomy.

CONCLUSIONS

A review of recent literatures providing complication rates for ASD surgery was performed, providing the most up-to-date incidence of early and late complications. Providers may use such data in helping to counsel patients of the literature-supported complication rates of such procedures despite the planned benefits, thus obtaining a more thorough informed consent.

Mineralized Collagen: Rationale, Current Status, and Clinical Applications

This paper presents a review of the rationale for the in vitro mineralization process, preparation methods, and clinical applications of mineralized collagen. The rationale for natural mineralized collagen and the related mineralization process has been investigated for decades. Based on the understanding of natural mineralized collagen and its formation process, many attempts have been made to prepare biomimetic materials that resemble natural mineralized collagen in both composition and structure. To date, a number of bone substitute materials have been developed based on the principles of mineralized collagen, and some of them have been commercialized and approved by regulatory agencies. The clinical outcomes of mineralized collagen are of significance to advance the evaluation and improvement of related medical device products. Some representative clinical cases have been reported, and there are more clinical applications and long-term follow-ups that currently being performed by many research groups.

Segmental kyphosis after cervical interbody fusion with stand-alone polyetheretherketone (PEEK) cages: a comparative study on 2 different PEEK cages

STUDY DESIGN

Retrospective comparative study.

OBJECTIVE

Two polyetheretherketone (PEEK) cages of different designs were compared in terms of the postoperative segmental kyphosis after anterior cervical discectomy and fusion.

SUMMARY OF BACKGROUND DATA

Segmental kyphosis occasionally occurs after the use of a stand-alone cage for anterior cervical discectomy and fusion. Although PEEK material seems to have less risk of segmental kyphosis compared with other materials, the occurrence of segmental kyphosis for PEEK cages has been reported to be from 0% to 29%. There have been a few reports that addressed the issue of PEEK cage design.

METHOD

A total of 41 consecutive patients who underwent single-level anterior discectomy and fusion with a stand-alone cage were included. Either a round tube-type (Solis; 18 patients, S-group) or a trapezoidal tube-type (MC+; 23 patients, M-group) cage was used. The contact area between the cage and the vertebral body is larger in MC+ than in Solis, and anchoring pins were present in the Solis cage. The effect of the cage type on the segmental angle (SA) (lordosis vs. kyphosis) at postoperative month 24 was analyzed.

RESULTS

Preoperatively, segmental lordosis was present in 12/18 S-group and 16/23 M-group patients (P=0.84). The SA was more lordotic than the preoperative angle in both groups just after surgery, with no difference between groups (P=0.39). At 24 months, segmental lordosis was observed in 9/18 S-group and 20/23 M-group patients (P=0.01). The patients in M-group were 7.83 times more likely than patients in S-group (P=0.04; odds ratio, 7.83; 95% confidence interval, 1.09-56.28) not to develop segmental kyphosis.

CONCLUSIONS

The design of the PEEK cage used may influence the SA, and this association needs to be considered when using stand-alone PEEK cages.

Surgical treatments for degenerative lumbar scoliosis: a meta analysis

PURPOSE

Degenerative lumbar scoliosis (DLS) is a spinal deformity that typically develops in adults over 50 years old. Although its etiology is unclear, asymmetric degeneration of the spine is the main cause. Individuals with DLS may experience no symptoms of the deformity, mild symptoms, or severe disability. Most patients with DLS receive conservative treatment, while a small number of patients receive surgery for severe DLS with back pain and/or progressive neurological symptoms. A variety of surgical procedures have emerged. However, a systemic comparison of these surgical procedures is currently unavailable. This study reviews the main outcomes and complications of surgical treatments.

METHODS

A meta analysis of main outcomes and complications of surgical treatments of DLS was conducted through searching PubMed and EMbase databases.

RESULTS

A total of 45 studies were included in this study, which were classified into four surgical categories. Nine studies utilized isolated decompression, 12 used short interbody fusion, 17 used long interbody fusion, and 11 studies included patients using short or long interbody fusion or surgery other than fusion, respectively. Decompression surgery is used to release the symptoms of neurogenic claudication. Spine fusion is widely utilized to prevent worsening of the curve. Instrumentation has been used together with fusion to straighten the spine, correct sagittal imbalance, and repair rotational defects. Decompression is commonly combined with fusion surgery when treating an individual with DLS.

CONCLUSION

Despite a high rate of complications, this review demonstrates that surgery is an effective and reasonable treatment intervention for severe DLS and ultimately improves spine function and deformity. This review also suggests that large scale, high quality studies with long term follow-up are needed to provide more reliable evidence for future evaluation.

Adult Degenerative Scoliosis Surgical Outcomes: A Systematic Review and Meta-analysis

INTRODUCTION

There is increasing awareness of adult degenerative or de novo scoliosis, and its surgical treatment when indicated can be challenging and resource intense. Surgical randomized controlled trials are rare, and observational studies pose limitations because of the heterogeneity of surgical practices, techniques, and patient populations. Pooled analysis of current literature may identify effective treatment strategies and guide future efforts at prospective clinical research. This study aimed to synthesize existing data on the outcomes of surgical intervention for adult degenerative scoliosis.

METHODS

PubMed, Medline, Cochrane, and Web of Science databases were searched using key words and were limited to the English language. Spine surgeons reviewed abstracts and evaluated whether they contained surgically treated cohorts of adults (more than 18 years of age) with degenerative scoliosis. Full-text articles were reviewed in detail and data were abstracted. All meta-analyses were conducted using random effects models and heterogeneity was estimated with I². Random-effects meta-regression models were used to investigate the association of treatment effects with baseline levels of each outcome.

RESULTS

Of 482 articles, 24 (n = 805) met inclusion criteria Available outcomes included Cobb angle correction, coronal and sagittal balance, visual analog scale for pain (VAS), and Oswestry Disability Index. Despite significant heterogeneity among studies, random-effects meta-analysis showed significant improvements in Cobb angle (-11.1°; 95% confidence interval [CI], -13.86° to -8.40°), coronal balance (7.674 mm; 95% CI, -10.5 to -4.9), VAS (-3.24; 95% CI, -4.5 to -1.98), and Oswestry Disability Index (-27.18%; 95% CI, -34.22 to -20.15) postoperative treatment (p < .001). Meta-regression models showed that preoperative values for Cobb angle, coronal balance, and VAS were significantly associated with surgical treatment effect (p < .05). Changes in sagittal balance did not reach statistical significance although only 6 articles were included.

CONCLUSIONS

Exhaustive literature review yielded 24 studies reporting preoperative and postoperative data regarding the surgical treatment of adult degenerative scoliosis. No randomized clinical trials (RCTs) were identified. Despite heterogeneity, a limited meta-analysis showed significant improvement in Cobb angle, coronal balance, and VAS after surgical treatment of adult degenerative scoliosis.

Bone graft substitutes currently available in orthopaedic practice: the evidence for their use

We reviewed 59 bone graft substitutes marketed by 17 companies currently available for implantation in the United Kingdom, with the aim of assessing the peer-reviewed literature to facilitate informed decision-making regarding their use in clinical practice. After critical analysis of the literature, only 22 products (37%) had any clinical data. Norian SRS (Synthes), Vitoss (Orthovita), Cortoss (Orthovita) and Alpha-BSM (Etex) had Level I evidence. We question the need for so many different products, especially with limited published clinical evidence for their efficacy, and conclude that there is a considerable need for further prospective randomised trials to facilitate informed decision-making with regard to the use of current and future bone graft substitutes in clinical practice.

Current status of adult spinal deformity

Purpose To review the current literature for the nonoperative and operative treatment for adult spinal deformity. Recent Findings With more than 11 million baby boomers joining the population of over 60 years of age in the United States, the incidence of lumbar deformity is greatly increasing. Recent literature suggests that a lack of evidence exists to support the effectiveness of nonoperative treatment for adult scoliosis. In regards to operative treatment, current literature reports a varying range of improved clinical outcomes, curve correction, and complication rates. The extension of fusion to S1 compared with L5 and lower thoracic levels compared with L1 remains a highly controversial topic among literature. Summary Most adult deformity patients never seek nonoperative or operative treatment. Of the few that seek treatment, many can benefit from nonoperative treatment. However, in selected patients who have failed nonoperative treatment and who are candidates for surgical intervention, the literature reflects positive outcomes related to surgical intervention as compared with nonoperative treatment despite varying associated ranges in morbidity and mortality rates. If nonoperative therapy fails in addressing a patient's complaints, then an appropriate surgical procedure that relieves neural compression, corrects excessive sagittal or coronal imbalance, and results in a solidly fused, pain-free spine is warranted.

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.

Application of scaffolds for bone regeneration strategies: current trends and future directions

Scaffolds are extensively used in surgery to replace missing bone and to achieve bony union and fusion. An ideal scaffold should not only maintain, induce, and restore biological functions where cells, extracellular matrix, and growth factors are needed, but also have the right properties with respect to degradation, cell binding, cellular uptake, non-immunogenicity, mechanical strength, and flexibility. Here we examine both the basic science behind the development of scaffolds and comprehensively and systematically review the clinical applications.

Surgery is an Effective and Reasonable Treatment for Degenerative Scoliosis: A Systematic Review

OBJECTIVE: A systematic review to evaluate the role of surgery for treating degenerative scoliosis (DS) in terms of improved function (Oswestry Disability Index [ODI]) and correction of deformity (Cobb angle); safety outcomes included complication and repeat surgery rates. METHODS: A search of the MEDLINE, ISI Web of Knowledge and Cochrane Library databases was performed. The methodological quality of each study was assessed according to standardized criteria and data were extracted. RESULTS: A total of 16 studies including 553 patients with DS met the eligibility criteria for inclusion. The mean ODI score at final follow-up was 36.0 ± 7.8 (304 patients) and the mean decrease in ODI was 23.3 ± 11.3 (302 patients). Mean reduction in curve angle (as a percentage of the original curve) was 48.5 ± 21.0% (527 patients). The overall incidence of complications was 49.0% (171 in 349 patients) and the rate of repeat surgery was 15.3% (61 in 398 patients). CONCLUSIONS: Despite a high incidence of complications and reoperations, surgery was an effective and reasonable treatment for DS, providing significant functional improvement and deformity correction.