Iliac Crest Bone Graft in Lumbar Fusion: The Effectiveness and Safety Compared with Local Bone Graft, and Graft Site Morbidity Comparing a Single-Incision Midline Approach with a Two-Incision Traditional Approach

A new option for bone regeneration: a rapid methodology for cellularization of allograft with human bone marrow stromal cells with in vivo bone-forming potential

The treatment of severe musculoskeletal injuries, such as loss of bone tissue and consolidation disorders, requires bone transplantation, and the success of this bone reconstruction depends on the grafts transplant's osteogenic, osteoconductive, and osteoinductive properties. Although the gold standard is autograft, it is limited by availability, morbidity, and infection risk. Despite their low capacity for osteoinduction and osteogenesis, decellularized bone allografts have been used in the search for alternative therapeutic strategies to improve bone regeneration. Considering that bone marrow stromal cells (BMSCs) are responsible for the maintenance of bone turnover throughout life, we believe that associating BMSCs with allograft could produce a material that is biologically similar to autologous bone graft. For this reason, this study evaluated the osteogenic potential of bone allograft cellularized with BMSCs. First, BMSC was characterized and allograft decellularization was confirmed by histology, scanning electron microscopy, and DNA quantification. Subsequently, the BMSCs and allografts were associated and evaluated for adhesion, proliferation, and in vitro and in vivo osteogenic potential. We demonstrated that, after 2 hours, BMSCs had already adhered to the surface of allografts and remained viable for 14 days. In vitro osteogenic assays indicated increased osteogenic potential of allografts compared with beta-tricalcium phosphate (β-TCP). In vivo transplantation assays in immunodeficient mice confirmed the allograft's potential to induce bone formation, with significantly better results than β-TCP. Finally, our results indicate that allograft can provide structural support for BMSC adhesion, offering a favorable microenvironment for cell survival and differentiation and inducing new bone formation. Taken together, our data indicate that this rapid methodology for cellularization of allograft with BMSCs might be a new therapeutic alternative in regenerative medicine and bone bioengineering.

Biportal endoscopic decompression, debridement, and interbody fusion, combined with percutaneous screw fixation for lumbar brucellosis spondylitis

Objective

This study aims to investigate the effectiveness and feasibility of biportal endoscopic decompression, debridement, and interbody fusion, combined with percutaneous screw fixation for lumbar brucellosis spondylitis (LBS).

Methods

The data of 13 patients with LBS were retrospectively analyzed, who underwent biportal endoscopic decompression, debridement, and interbody fusion, combined with percutaneous screw fixation from May 2020 to June 2022. The patients' clinical data, the duration of operation, the estimated blood loss (including postoperative drainage), and complications were recorded. Clinical outcomes include serum agglutination test (SAT) measures Brucella antibody titer, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), the visual analog scale (VAS) scores of low back and leg, Japanese Orthopaedic Association (JOA) score, Oswestry Disability Index (ODI), American Spinal Injury Association neurological classification, and lordotic angle were analyzed. All patients were assessed using the modified Macnab criteria at the final follow-up. The intervertebral bone graft fusion was assessed using the Bridwell grading criteria.

Results

The mean operation duration was 177.31 ± 19.54 min, and the estimated blood loss was 176.15 ± 43.79 ml (including postoperative drainage was 41.15 ± 10.44 ml). The mean follow-up period was 13.92 ± 1.5 months. SAT showed that the antibody titers of 13 patients were normal 3 months after the operation and at the final follow-up. ESR and CRP levels returned to normal by the end of the 3-month follow-up. VAS scores of low back and leg, JOA score, and ODI significantly improved after the operation throughout the follow-up period (P < 0.05). Based on the modified Macnab criteria, 92.3% showed excellent to good outcomes. One patient had only a percutaneous screw internal fixation on the decompression side due to severe osteoporosis. One case suffered a superficial incision infection postoperatively that healed with dressing change and effective antibiotic treatment. Bony fusion was obtained in all patients at the last follow-up, including 12 cases with grade I and 1 case with grade II, with a fusion rate of 92.31%.

Conclusion

Biportal endoscopic decompression, debridement, and interbody fusion, combined with percutaneous screw fixation is an effective, safe, and viable surgical procedure for the treatment of LBS.

Does conflict of interest affect the reported fusion rates of bone graft substitutes and extenders?

Background

Bone graft extenders are being used more in spine surgery as a substitute for iliac crest bone graft. However, potential conflict of interest could impact average fusion rates. The purpose of this study was to evaluate whether fusion rates reported in the literature were different in papers evaluating bone graft substitutes and extenders when there was potential conflict of interest versus no potential conflict of interest.

Methods

Pubmed was searched for studies evaluating fusion rates when bone graft extenders including demineralized bone matrix, hydroxyapatite, and tricalcium sulfate were used. Studies were screened for one or two level fusions and for degenerative spinal conditions. The average fusion rates of subgroups were compared using unpaired Student's t-tests.

Results

1928 studies were evaluated. 86 studies were included in the study. The fusion rates varied from 4 to 100%. There were 24 studies with a potential conflict of interest and 62 studies with no conflict of interest. The average fusion rate of all the studies was 84.63% with standard deviation of 18.33%. The average fusion rates of those studies with conflict of interest was 80.93% versus 86.06% without conflict of interest. This was not statistically significant (p>0.07). The average fusion rate of studies evaluated by CT scan was 79.8% versus 87.9% without CT. The average fusion rate of studies that employed an independent reviewer to evaluate the fusion was 82.61% versus 85.63% for studies with no independent reviewer.

Conclusion

There is a great variability in the reported fusion rates of bone graft extenders. Counter to expectations, average fusion rates were lower in the studies where there was a potential conflict of interest. The use of CT scans and an independent reviewer seem to account for the lower reported fusion rates, and may be a means of negating the potential conflicts of interest in fusion studies.

Level of Evidence

2

Local Autograft Versus Iliac Crest Bone Graft PSF-Augmented TLIF in Low-Grade Isthmic and Degenerative Lumbar Spondylolisthesis

STUDY DESIGN

Prospective randomized controlled cohort study.

OBJECTIVE

To compare the outcome of local autograft versus iliac crest bone graft (ICBG) stand-alone transforaminal lumbar interbody fusion (TLIF) in lumbar spondylolisthesis.

METHODS

One hundred eight patients with low-grade single-level spondylolisthesis underwent operation with pedicular screw fixation (PSF)-augmented stand-alone TLIF. Patients were randomly divided into groups according to bone graft: group I, autograft group; and group II, ICBG group, with 54 patients each. Fifty-nine patients had isthmic spondylolisthesis and 49 had degenerative spondylolisthesis. Clinical outcome parameters included Visual Analogue Scale (VAS), Oswestry Disability Index (ODI), and patient's satisfaction, while the radiological parameters included fusion rate, slip reduction, segmental angle, and disc height. The mean follow-up period was 38 ± 19 months, with a minimum 24 of months.

RESULTS

The preoperative VAS of back pain improved from 8 ± 3.1 to 3.4 ± 2.9 and from 8 ± 3.2 to3.6 ± 2.6 in group I and group II, respectively. The preoperative ODI improved from 41.4 ± 8 to 12.3 ± 7 and from 39 ± 9 to 13 ± 8 in group I and group II, respectively. The fusion rate was 93% in group I and 94.5% in group II. The percentage of slip was reduced from 26.7 ± 7.1% to 16.5 ± 6.1% in group I and from 27.4 ± 8.25 to 15.8 ± 5.2% in group II. Intervertebral disc height increased from 25.27 ± 14.62 to 46.38 ± 15.41 in group I and from 22.29 ± 13.72 to 45.15 ± 16.77 in group II. Segmental angle improved from 10.5 ± 8.1° to 16.7 ± 5.4° in group I and from 11.6 ± 5.3° to 15.9 ± 6.2° in group II. There was no significant difference of the above-mentioned parameters between the 2 groups.

CONCLUSION

Patients with single-level low-grade spondylolisthesis can be effectively treated with PSF-augmented stand-alone TLIF using either local autograft or ICBG with no outcome differences between the 2 groups.

Comparing porous tantalum fusion implants and iliac crest bone grafts for spondylodesis of thoracolumbar burst fractures: Prospectice Cohort study

The aim of this study was to compare two different techniques of performing one-level spondylodesis for thoracolumbar burst fractures using either an autologous iliac crest bone graft (ICBG) or a porous tantalum fusion implant (PTFI). In a prospective nonrandomized study, 44 patients (20 women, 24 men; average age 43.1 ± 13.2 years) suffering from severe thoracolumbar burst fractures were treated with combined anterior–posterior stabilization. An ICBG was used in 21 cases, and a PTFI was used in the other 23 cases. A two-year clinical and radiographic follow-up was carried out. There were no statistically significant differences in age, sex, localization/classification of the fracture, or visual analog scale (VAS) before injury between the two groups. All 44 patients were followed up for an average period of 533 days (range 173–1567). The sagittal spinal profile was restored by an average of 11.1° (ICBG) vs. 14.3° (PTFI) (monosegmental Cobb angle). Loss of correction until the last follow-up tended to be higher in the patients treated with ICBG than in those treated with PTFI (mean: 2.8° vs. 1.6°). Furthermore, significantly better restoration of the sagittal profile was obtained with the PTFI than with the iliac bone graft at the long-term follow-up (mean: ICBG 7.8°, PTFI 12.3°; p < 0.005). Short-segment posterior instrumentation combined with anterior one-level spondylodesis using either an ICBG or a PTFI resulted in sufficient correction of posttraumatic segmental kyphosis. PTFI might be a good alternative for autologous bone grafting and prevent donor site morbidities.

Bone Substitutes in Orthopaedic Surgery: Current Status and Future Perspectives

Bone replacement materials have been successfully supplied for a long time. But there are cases, especially in critical sized bone defects, in which the therapy is not sufficient. Nowadays, there are multiple bone substitutes available. Autologous bone grafts remain the "gold standard" in bone regeneration. Yet, donor-site morbidity and the available amount of sufficient material are limitations for autologous bone grafting. This study aimed to provide information about the current status in research regarding bone substitutes. We report on the advantages and drawbacks of several bone substitutes. At the end, we discuss the current developments of combining ceramic substitutes with osteoinductive substances.

Patient Perceptions of Iliac Crest Bone Grafting in Minimally Invasive Transforaminal Lumbar Interbody Fusion

STUDY DESIGN

Retrospective cohort.

OBJECTIVE

The objective of this study was to determine patients' perception of iliac crest bone graft (ICBG) harvesting and donor site pain following minimally invasive transforaminal lumbar interbody fusion (MIS TLIF).

SUMMARY OF BACKGROUND DATA

The incidence of donor site pain has been debated in the literature because of the varying techniques associated with its harvest.

METHODS

Patients undergoing primary, single-level MIS TLIF with ICBG were retrospectively identified. ICBG harvesting was performed using a percutaneous technique with a tubular retractor. A survey was administered to assess if patients could accurately describe which side of their iliac crest they believed was harvested, and if they were experiencing any pain perceived to be originating from the donor site. Patient characteristics were compared using χ analysis and independent t test.

RESULTS

In total, 82 patients were included. The majority of patients had the ICBG harvested from the left iliac crest (97.5%). Approximately half of the patients correctly identified the side of harvest (50.6%). 48.1% of patients reported they were not confident or had guessed on their response. Patients that reported pain from the ICBG were more likely to feel confident or somewhat confident in their harvest site identification (57.9% vs. 46.3%) but less likely to be correct (36.8% vs. 63.4%) than patients without pain. 22 patients (27.8%) correctly identified the side of harvest without guessing. Of these, 11 (13.9%) reported pain.

CONCLUSIONS

Approximately half of patients undergoing MIS TLIF with ICBG are able to correctly identify which side of their iliac crest was harvested. However, the majority of patients reporting pain were unable to correctly identify the side of harvest. This suggests that most patients are likely attributing other sources of pain to their ICBG. Therefore, rates of donor site pain may be over-reported in the current literature with contemporary harvesting techniques.

Current Updates on Bone Grafting Biomaterials and Recombinant Human Growth Factors Implanted Biotherapy for Spinal Fusion: A Review of Human Clinical Studies

BACKGROUND

Owing to their great promise in the spinal surgeries, bone graft substitutes have been widely investigated for their safety and clinical potential. By the current advances in the spinal surgery, an understanding of the precise biological mechanism of each bone graft substitute is mandatory for upholding the induction of solid spinal fusion.

OBJECTIVE

The aim of the present review is to critically discuss various surgical implications and level of evidence of most commonly employed bone graft substitutes for spinal fusion.

METHOD

Data was collected via electronic search using "PubMed", "SciFinder", "ScienceDirect", "Google Scholar", "Web of Science" and a library search for articles published in peer-reviewed journals, conferences, and e-books.

RESULTS

Despite having exceptional inherent osteogenic, osteoinductive, and osteoconductive features, clinical acceptability of autografts (patient's own bone) is limited due to several perioperative and postoperative complications i.e., donor-site morbidities and limited graft supply. Alternatively, allografts (bone harvested from cadaver) have shown great promise in achieving acceptable bone fusion rate while alleviating the donor-site morbidities associated with implantation of autografts. As an adjuvant to allograft, demineralized bone matrix (DBM) has shown remarkable efficacy of bone fusion, when employed as graft extender or graft enhancer. Recent advances in recombinant technologies have made it possible to implant growth and differentiation factors (bone morphogenetic proteins) for spinal fusion.

CONCLUSION

Selection of a particular bone grafting biotherapy can be rationalized based on the level of spine fusion, clinical experience and preference of orthopaedic surgeon, and prevalence of donor-site morbidities.

Use of Recombinant Human Bone Morphogenetic Protein-2 at the C1-C2 Lateral Articulation without Posterior Structural Bone Graft in Posterior Atlantoaxial Fusion in Adult Patients

BACKGROUND

Posterior atlantoaxial fusion is an important armamentarium for neurosurgeons to treat several pathologies involving the craniovertebral junction. Although the potential advantages of recombinant human bone morphogenetic protein-2 (rhBMP-2) are well documented in the lumbar spine, its indication for C1-C2 fusion has not been well characterized. In our institution, we apply rhBMP-2 to the C1-C2 joint either alone or with hydroxyapatite, locally harvested autograft chips, and/or morselized allogenic bone graft for selected cases-without conventional posterior structural bone graft. We report the clinical outcomes of the surgical technique to elucidate its feasibility.

METHODS

We performed a single-center, retrospective review of data from 2008 to 2016 and identified 69 patients who had undergone posterior atlantoaxial fusion with rhBMP-2. The clinical records of these patients were reviewed, and the baseline characteristics, operative data, and postoperative complications were collected and statistically analyzed.

RESULTS

The average age of the 69 patients was 60.8 ± 4.5 years, and 55.1% were women. With an average follow-up period of 21.1 ± 4.2 months, the C1-C2 fusion rate was 94.3% (65 of 69), and the average time to fusion was 11.4 ± 2.6 months (range, 5-23). The overall reoperation rate was 10.1% (7 of 69), with instrumentation failure in 7 patients (10.1%), adjacent segment disease in 2 (2.9%), and postoperative dysphagia and dyspnea in 2 patients (2.9%). No ectopic bone formation or soft tissue edema developed.

CONCLUSIONS

Although retrospective and from a single center, our study has shown that rhBMP-2 usage at the C1-C2 joint without posterior structural bone grafting is a safe and reasonable surgical option.

EFFECT OF PULSED ELECTROMAGNETIC FIELD ON THE CONSOLIDATION OF POSTEROLATERAL ARTHRODESES IN THE LUMBOSACRAL SPINE: A PROSPECTIVE, DOUBLE-BLIND, RANDOMIZED STUDY

ABSTRACT Objective: To assess the effect of pulsed electromagnetic field (PEMF) on the consolidation of instrumented lumbar posterolateral arthrodeses in patients who have been surgically treated for degenerative spine disease. Methods: Forty cases were recruited from 163 consecutive patients undergoing lumbar arthrodesis at the same center. The patients were randomized into two groups of 20 patients: Active Group, who were exposed to PEMF for 4 hours a day for 90 days after surgery, and Inactive Group, who received an identical device, with the same instructions for use but without the ability to generate PEMF. The patients underwent computed tomography scans at 45, 90, 180 and 360 days after surgery to check for the occurrence of arthrodesis at each operated spinal level. Results: In the course of the study, two patients were excluded from each group. There were no significant differences between the groups with respect to age, gender, smoking habit, or the number of vertebral levels included in the arthrodesis. The percentage of consolidation of the vertebral levels increased at 90, 180 and 360 days compared to 45 days (p<0.001) in both groups. The Active Group had a 276% greater chance of consolidation in the vertebral levels (OR = 3.76; 95% CI: 1.39-10.20), regardless of the time of evaluation. Patients in the Active Group presented 16% more consolidation than patients in the inactive group (p=0.018). Conclusions: Post-operative exposure to PEMF following instrumented arthrodesis of the lumbar spine for degenerative spine disease increased consolidation in the first year after surgery.

Results of lumbar spondylodeses using different bone grafting materials after transforaminal lumbar interbody fusion (TLIF)

PURPOSE

Can a mixture of hydroxyapatite (HA) and autologous bone from decompression sites produce similar results when used for transforaminal lumbar interbody fusion (TLIF)? In the current literature, autologous iliac crest bone grafts (ICBGs) have been reported the gold standard for this procedure. Indeed, to date, no clinical data have confirmed that a mixture of equal volumes of HA and local autologous bone produce similar results in term of fusion as the same volume of autologous ICBG alone.

METHODS

Study design/setting This study was approved by the local ethics committee and completed in a prospective, randomized, single-blinded manner. The results of lumbar fusion using TLIF and different bone grafting materials were compared. Patient sample The patient sample included patients with spinal lumbar degenerative disease. Outcome measures The clinical outcome was determined using the Oswestry Low Back Pain Disability Questionnaire (ODI) and Visual Analog Scale (VAS). The radiological outcomes and fusion rates were determined with radiographs evaluated using the McAfee criteria and computed tomography (CT) data evaluated by the Williams criteria. Three blinded investigators (one radiologist and two orthopedic surgeons) assessed the data. The secondary variables included donor site morbidity. Methods The patients were admitted to our department for orthopedic surgery with degenerative lumbar pathologies (L2-S1) that required stabilization in one or two segments using a TLIF procedure. The patients were 18-80 years old. Only those patients who had degenerative lumbar pathologies and agreed to be educated about the study were included. The patients were divided into the following two randomized groups: group A: TLIF procedure using autologous ICBGs alone; and group B: TLIF procedure using local bone from decompression site mixed with hydroxyapatite. Each group received equal graft volumes. The mixture in group B consisted of equal volumes of local autograft (5 cc) and synthetic bone (5 cc). A graft volume of 10 cc was used at each fusion level. The patients were followed up at three appointments at 1.5, 6 and 12 months postoperatively. Every patient received detailed education about the course of the study.

RESULTS

Forty-eight patients finished the study (2 patients dropped out). The radiographic fusion rate did not significantly differ between the two groups. Based on the CT criteria, 83.3% of the patients showed fusion in both groups after 12 months. Furthermore, 95.3% of the patients in group A and 91.7% of the patients in group B showed bony spondylodeses according to the radiographic criteria at the 12-month follow-up. The donor site morbidity consisted of one patient with a wound infection and one with a hematoma in group A and two patients with persistent pain in group B. Group A also included one patient with cage subsidence of 4 mm and archived fusion after 12 months. In group B, one patient had a pedicle screw breakage and achieved fusion after 6 months. The clinical outcomes were similar between the two groups. In both groups, the VAS and ODI data improved during the follow-up period (p < 0.05). No patients required additional surgeries.

CONCLUSIONS

Both groups demonstrated equivalent clinical outcomes. HA and autologous bone from decompression sites can achieve similar fusion rates to those achieved with identical volumes of the gold standard autologous graft. The graft mixture can be used for one- or two-level lumbar spondylodeses to avoid donor site morbidity.

Dynamic cultivation with radial flow bioreactor enhances proliferation or differentiation of rat bone marrow cells by fibroblast growth factor or osteogenic differentiation factor

Dynamic cultivation using a radial flow bioreactor (RFB) has gained increasing interest as a method of achieving bone regeneration. In order to enhance bone generation in large bone defects, it is necessary to use an RFB to expand the primary cells such as bone marrow cells derived from biotissue. The present study aimed to evaluate the cell expansion and osteogenic differentiation of rat bone marrow cells (rBMC) when added to basic fibroblast growth factor containing medium (bFGFM) or osteogenic differentiation factor containing medium (ODM) under dynamic cultivation using an RFB. Cell proliferation was evaluated with a DNA-based cell count method and histological analysis. An alkaline phosphatase (ALP) activity assay and immunohistochemistry staining of osteogenic markers including BMP-2 and osteopontin were used to assess osteogenic differentiation ability. After culture for one week, rBMC cell numbers increased significantly under dynamic cultivation compared with that under static cultivation in all culture media. For different culture media in dynamic cultivation, bFGFM had the highest increase in cell numbers. ALP activity was facilitated by dynamic cultivation with ODM. Furthermore, both BMP-2 and osteopontin were detected in the dynamic cultivation with ODM. These results suggested that bFGFM promotes cell proliferation and ODM promotes osteogenic differentiation of rBMC under dynamic cultivation using an RFB.

Variables Affecting Fusion Rates in the Rat Posterolateral Spinal Fusion Model with Autogenic/Allogenic Bone Grafts: A Meta-analysis

The rat posterolateral spinal fusion model with autogenic/allogenic bone graft (rat PFABG) has been increasingly utilized as an experimental model to assess the efficacy of novel fusion treatments. The objective of this study was to investigate the reliability of the rat PFABG model and examine the effects of different variables on spinal fusion. A web-based literature search from January, 1970 to September, 2015, yielded 26 studies, which included 40 rat PFABG control groups and 449 rats. Data regarding age, weight, sex, and strain of rats, graft volume, graft type, decorticated levels, surgical approach, institution, the number of control rats, fusion rate, methods of fusion assessment, and timing of fusion assessment were collected and analyzed. The primary outcome variable of interest was fusion rate, as evaluated by manual palpation. Fusion rates varied widely, from 0 to 96%. The calculated overall fusion rate was 46.1% with an I ² value of 62.4, which indicated moderate heterogeneity. Weight >300 g, age >14 weeks, male rat, Sprague-Dawley strain, and autogenic coccyx grafts increased fusion rates with statistical significance. Additionally, an assessment time-point ≥8 weeks had a trend towards statistical significance (p = 0.070). Multi-regression analysis demonstrated that timing of assessment and age as continuous variables, as well as sex as a categorical variable, can predict the fusion rate with R ² = 0.82. In an inter-institution reliability analysis, the pooled overall fusion rate was 50.0% [44.8, 55.3%], with statistically significant differences among fusion outcomes at different institutions (p < 0.001 and I ² of 72.2). Due to the heterogeneity of fusion outcomes, the reliability of the rat PFABG model was relatively limited. However, selection of adequate variables can optimize its use as a control group in studies evaluating the efficacy of novel fusion therapies.