Osteoconductive bone graft extenders in posterolateral thoracolumbar spinal fusion: a systematic review

Assessing the potential role of ChatGPT in spine surgery research

Purpose

Since its release in November 2022, Chat Generative Pre-Trained Transformer 3.5 (ChatGPT), a complex machine learning model, has garnered more than 100 million users worldwide. The aim of this study is to determine how well ChatGPT can generate novel systematic review ideas on topics within spine surgery.

Methods

ChatGPT was instructed to give ten novel systematic review ideas for five popular topics in spine surgery literature: microdiscectomy, laminectomy, spinal fusion, kyphoplasty and disc replacement. A comprehensive literature search was conducted in PubMed, CINAHL, EMBASE and Cochrane. The number of nonsystematic review articles and number of systematic review papers that had been published on each ChatGPT-generated idea were recorded.

Results

Overall, ChatGPT had a 68% accuracy rate in creating novel systematic review ideas. More specifically, the accuracy rates were 80%, 80%, 40%, 70% and 70% for microdiscectomy, laminectomy, spinal fusion, kyphoplasty and disc replacement, respectively. However, there was a 32% rate of ChatGPT generating ideas for which there were 0 nonsystematic review articles published. There was a 71.4%, 50%, 22.2%, 50%, 62.5% and 51.2% success rate of generating novel systematic review ideas, for which there were also nonsystematic reviews published, for microdiscectomy, laminectomy, spinal fusion, kyphoplasty, disc replacement and overall, respectively.

Conclusions

ChatGPT generated novel systematic review ideas at an overall rate of 68%. ChatGPT can help identify knowledge gaps in spine research that warrant further investigation, when used under supervision of an experienced spine specialist. This technology can be erroneous and lacks intrinsic logic; so, it should never be used in isolation.

Level of Evidence

Not applicable.

Ceramic bone graft substitute (Mg-HA) in spinal fusion: A prospective pilot study

Background: Iliac crest bone graft (ICBG) is considered the gold standard for spine surgical procedures to achieve a successful fusion due to its known osteoinductive and osteoconductive properties. However, complications related to harvesting procedure and donor site morbidity have been largely reported in the literature, favoring the development of a wide range of alternative products to be used as bone graft extenders or substitutes for spine fusion. Among all, ceramic-based biomaterials have been widely studied and employed in the last years as bone graft substitutes. Methods: We report here the results of a prospective pilot study aimed to evaluating the grade of ossification obtained by the use of an Mg-doped hydroxyapatite (HA) product to achieve postero-lateral fusion in degenerative spine diseases. Results: Results show a successful degree of fusion of about 62% at the 12-month follow-up and an improvement of quality of life and health status following surgery, as evaluated by clinical scores (ODI, VAS, and EQ-5L). No adverse events related to the material were reported. Conclusion: The present pilot study shows the effectiveness and the safety profile of an Mg-doped HA bone graft substitute used to achieve postero-lateral fusion in the treatment of degenerative spine diseases, laying down the basis for further larger clinical investigations.

Posterior Thoracic Cage Interbody Fusion Offers Solid Bone Fusion with Sagittal Alignment Preservation for Decompression and Fusion Surgery in Lower Thoracic and Thoracolumbar Spine

OBJECTIVE

It is challenging to make solid fusion by posterior screw fixation and laminectomy with posterolateral fusion (PLF) in thoracic and thoracolumbar (TL) diseases. In this study, we report our experience and follow-up results with a new surgical technique entitled posterior thoracic cage interbody fusion (PTCIF) for thoracic and TL spine in comparison with conventional PLF.

METHODS

After institutional review board approval, a total of 57 patients who underwent PTCIF (n=30) and conventional PLF (n=27) for decompression and fusion in thoracic and TL spine between 2004 and 2019 were analyzed. Clinical outcomes and radiological parameters, including bone fusion, regional Cobb angle, and proximal junctional Cobb angle, were evaluated.

RESULTS

In PTCIF and conventional PLF, the mean age was 61.2 and 58.2 years (p=0.46), and the numbers of levels fused were 2.8 and 3.1 (p=0.46), respectively. Every patient showed functional improvement except one case of PTCIF. Postoperative hematoma as a perioperative complication occurred in one and three cases, respectively. The mean difference in the regional Cobb angle immediately after surgery compared with that of the last follow-up was 1.4° in PTCIF and 7.6° in conventional PLF (p=0.003), respectively. The mean durations of postoperative follow-up were 35.6 months in PTCIF and 37.3 months in conventional PLF (p=0.86).

CONCLUSION

PTCIF is an effective fusion method in decompression and fixation surgery with good clinical outcomes for various spinal diseases in the thoracic and TL spine. It provides more stable bone fusion than conventional PLF by anterior column support.

rhBMP in lumber fusion for lumbar spondylolisthesis: A systematic review and meta-analysis

PURPOSE

To compare the efficacy and safety of recombinant human bone morphogenetic protein (rhBMP) and iliac crest autograft in the fusion treatment of lumbar spondylolisthesis.

METHODS

The studies using randomized controlled trials to compare the rhBMP with iliac crest autograft in the treatment of lumbar spondylolisthesis were retrieved from Embase, Pubmed, ProQuest dissertations & theses (PQDT), China national knowledge infrastructure (CNKI), Chinese Biomedical Database, Wanfang Data, Cochrane Library (from March 1998 to March 2018). Postoperative fusion rate, clinical success rate, postoperative intervertebral height, complications, operation time, blood loss and duration of hospitalization were chosen as the outcome indicators. Methodological quality of the trials was critically assessed, and relevant data were extracted. Statistical software Revman 5.3 was used for data-analysis.

RESULTS

Eleven articles were included in the meta-analysis. The results showed that, comparing the efficacy of rhBMP with iliac crest autograft, statistical significance was found in the 24-month fusion rate post operation [95% CI (1.38, 24.70), p = 0.02] and operation time [95% CI (-14.22, -2.08), p = 0.008]. There is not sufficient evidence for statistical differences in the remaining indicators.

CONCLUSION

The current literature shows rhBMP is a safe and effective grafting material in the treatment of lumbar spondylolisthesis. Further evidence is dependent on the emergence of more randomized controlled trials with higher quality and larger sample sizes in the future.

Single-center, consecutive series study of the use of a novel platelet-rich fibrin matrix (PRFM) and beta-tricalcium phosphate in posterolateral lumbar fusion

PURPOSE

To evaluate the radiographic and clinical outcomes of the combination of platelet-rich fibrin matrix (PRFM) with beta-tricalcium phosphate (β-TCP) and bone marrow aspirate (BMA) as a graft alternative in posterolateral lumbar fusion procedures.

METHODS

Researchers evaluated 50 consecutive patients undergoing one-level to three-level posterolateral lumbar fusion procedures, resulting in a total of 66 operated levels. The primary outcome was evidence of radiographic fusion at 1-year follow-up, assessed by three independent evaluators using the Lenke scoring system. Secondary outcomes included back and leg VAS scores, incidence of reoperations and complications, return-to-work status, and opioid use.

RESULTS

At 1-year follow-up, radiographic fusion was observed in 92.4% (61/66) of operated levels. There was significant improvement in VAS scores for both back and leg pain (p < 0.05). Compared to baseline figures, the number of patients using opioid analgesics at 12-months decreased by 38%. The majority (31/50) of patients were retired, yet 68% of employed patients (n = 19) were able to return to work. No surgical site infections were noted, and no revision surgery at the operated level was required.

CONCLUSIONS

This is the first report to analyze the combination of PRFM with β-TCP and BMA for PLF procedures. Our results indicate a rate of fusion similar to those reported using iliac crest bone graft (ICBG), while avoiding donor site morbidity related to ICBG harvesting such as hematoma, pain, and infection. These slides can be retrieved under Electronic Supplementary Material.

Biphasic calcium phosphate with submicron surface topography in an Ovine model of instrumented posterolateral spinal fusion

As spinal fusions require large volumes of bone graft, different bone graft substitutes are being investigated as alternatives. A subclass of calcium phosphate materials with submicron surface topography has been shown to be a highly effective bone graft substitute. In this work, a commercially available biphasic calcium phosphate (BCP) with submicron surface topography (MagnetOs; Kuros Biosciences BV) was evaluated in an Ovine model of instrumented posterolateral fusion. The material was implanted stand-alone, either as granules (BCPgranules) or as granules embedded within a fast-resorbing polymeric carrier (BCPputty) and compared to autograft bone (AG). Twenty-five adult, female Merino sheep underwent posterolateral fusion at L2-3 and L4-5 levels with instrumentation. After 6, 12, and 26 weeks, outcomes were evaluated by manual palpation, range of motion (ROM) testing, micro-computed tomography, histology and histomorphometry. Fusion assessment by manual palpation 12 weeks after implantation revealed 100% fusion rates in all treatment groups. The three treatment groups showed a significant decrease in lateral bending at the fusion levels at 12 weeks (P < 0.05) and 26 weeks (P < 0.001) compared to the 6 week time-point. Flexion-extension and axial rotation were also reduced over time, but statistical significance was only reached in flexion-extension for AG and BCPputty between the 6 and 26 week time-points (P < 0.05). No significant differences in ROM were observed between the treatment groups at any of the time-points investigated. Histological assessment at 12 weeks showed fusion rates of 75%, 92%, and 83% for AG, BCPgranules and BCPputty, respectively. The fusion rates were further increased 26 weeks postimplantation. Similar trends of bone growth were observed by histomorphometry. The fusion mass consisted of at least 55% bone for all treatment groups 26 weeks after implantation. These results suggest that this BCP with submicron surface topography, in granules or putty form, is a promising alternative to autograft for spinal fusion.

Clinical outcomes of posterior thoracic cage interbody fusion (PTCIF) to treat trauma and degenerative disease of the thoracic and thoracolumbar junctional spine

Laminectomy followed by posterolateral fusion (PLF) is a standard procedure for thoracic and thoracolumbar (TL) compressive lesions. However, it is challenging to apply sufficient bone chips as the spinal cord is exposed after the laminectomy. Therefore, we performed posterior thoracic cage interbody fusion (PTCIF) as an alternative technique. A total of 25 patients operated with PTCIF technique between 2012 and 2017 were analyzed in our study. These patients required a posterior decompression and fusion in thoracic and TL spine for traumatic injury or degenerative disease. To evaluate the outcome of bone fusion, computed tomography (CT) was performed at least 3-4 months after PTCIF. The surgery was performed through insertion of screws and cages packed with autologous bone chips in a similar fashion to the posterior lumbar interbody fusion technique. Among 25 patients who underwent PTCIF, 22 patients were involved in our study. The mean age and follow-up interval were 58.6 (28-78) years and 27.1 (6-60) months, respectively. Traumatic spinal injury was diagnosed in 6 patients and degenerative disease in 16 patients. One level PTCIF was performed in 12 patients and 2 levels in 8 patients. After the operation, patients with degenerative disease showed neurological improvement, and trauma cases showed no neurological aggravation. Successful bone fusion was confirmed on CT for all patients. PTCIF is an effective treatment thereby we suggest this approach to be considered as an alternative procedure to decompression and fusion surgery in the thoracic and TL spine.

A new bioinspired collagen-hydroxyapatite bone graft substitute in adult scoliosis surgery: results at 3-year follow-up

Background

Spinal fusion is a common procedure used for surgical treatment of spinal deformity. In recent years, many bone graft substitutes (BGS) have been developed to provide good arthrodesis when the available autologous bone harvested from the patient is not enough. The aim of this study was to analyze the use of a new-generation composite material (RegenOss) made of Mg-hydroxyapatite nanoparticles nucleated on type I collagen to obtain long posterolateral fusion in adult scoliosis surgery.

Methods

A total of 41 patients who underwent spinal fusion for the treatment of adult scoliosis were retrospectively analyzed. According to Lenke classification, visual analog scale (VAS) score and Oswestry Disability Index (ODI) score, radiographic rates of bone union were evaluated before surgery and at 6, 12 and 36 months of follow-up. Fusion was considered to be successful when criteria for Lenke grade A or B were satisfied. Patient-related risk factors were considered for the evaluation of the final outcome.

Results

At 36-month follow-up, radiographic evidence of spinal fusion was present in the majority of patients (95.1%). A time-dependent statistically significant improvement was evidenced after surgery for all clinical outcomes evaluated. Based on the demographic data collected, there were no statistically significant factors determining fusion. The correction of deformity was maintained at different time points. No intraoperative or postoperative complications were recorded.

Conclusions

The present study demonstrated that RegenOss can safely be used to achieve good arthrodesis when associated with autologous bone graft to obtain long spinal fusion in the treatment of adult scoliosis.

Hybrid Biosynthetic Autograft Extender for Use in Posterior Lumbar Interbody Fusion: Safety and Clinical Effectiveness

Autologous iliac crest bone graft is the preferred option for spinal fusion, but the morbidity associated with bone harvest and the need for graft augmentation in more demanding cases necessitates combining local bone with bone substitutes. The purpose of this study was to document the clinical effectiveness and safety of a novel hybrid biosynthetic scaffold material consisting of poly(D,L-lactide-co-glycolide) (PLGA, 75:25) combined by lyophilization with unmodified high molecular weight hyaluronic acid (10-12% wt:wt) as an extender for a broad range of spinal fusion procedures. We retrospectively evaluated all patients undergoing single- and multi-level posterior lumbar interbody fusion at an academic medical center over a 3-year period. A total of 108 patients underwent 109 procedures (245 individual vertebral levels). Patient-related outcomes included pain measured on a Visual Analog Scale. Radiographic outcomes were assessed at 6 weeks, 3-6 months, and 1 year postoperatively. Radiographic fusion or progression of fusion was documented in 221 of 236 index levels (93.6%) at a mean (±SD) time to fusion of 10.2+4.1 months. Single and multi-level fusions were not associated with significantly different success rates. Mean pain scores (+SD) for all patients improved from 6.8+2.5 at baseline to 3.6+2.9 at approximately 12 months. Improvements in VAS were greatest in patients undergoing one- or two-level fusion, with patients undergoing multi-level fusion demonstrating lesser but still statistically significant improvements. Overall, stable fusion was observed in 64.8% of vertebral levels; partial fusion was demonstrated in 28.8% of vertebral levels. Only 15 of 236 levels (6.4%) were non-fused at final follow-up

Accelerated postero-lateral spinal fusion by collagen scaffolds modified with engineered collagen-binding human bone morphogenetic protein-2 in rats

Bone morphogenetic protein-2 (BMP-2) is a potent osteoinductive cytokine that plays a critical role in bone regeneration and repair. However, its distribution and side effects are major barriers to its success as therapeutic treatment. The improvement of therapy using collagen delivery matrices has been reported. To investigate a delivery system on postero-lateral spinal fusion, both engineered human BMP-2 with a collagen binding domain (CBD-BMP-2) and collagen scaffolds were developed and their combination was implanted into Sprague-Dawley (SD) rats to study Lumbar 4–5 (L4–L5) posterolateral spine fusion. We divided SD rats into three groups, the sham group (G1, n = 20), the collagen scaffold-treated group (G2, n = 20) and the BMP-2-loaded collagen scaffolds group (G3, n = 20). 16 weeks after surgery, the spines of the rats were evaluated by X-radiographs, high-resolution micro-computed tomography (micro-CT), manual palpation and hematoxylin and eosin (H&E) staining. The results showed that spine L4–L5 fusions occurred in G2(40%) and G3(100%) group, while results from the sham group were inconsistent. Moreover, G3 had better results than G2, including higher fusion efficiency (X score, G2 = 2.4±0.163, G3 = 3.0±0, p<0.05), higher bone mineral density (BMD, G2: 0.3337±0.0025g/cm3, G3: 0.4353±0.0234g/cm3. p<0.05) and more bone trabecular formation. The results demonstrated that with site-specific collagen binding domain, a dose of BMP-2 as low as 0.02mg CBD-BMP-2/cm³ collagen scaffold could enhance the posterolateral intertransverse process fusion in rats. It suggested that combination delivery could be an alternative in spine fusion with dramatically decreased side effects caused by high dose of BMP-2.

Cell based therapies as compared to autologous bone grafts for spinal arthrodesis

STUDY DESIGN

Systematic review.

OBJECTIVE

To compare the clinical outcome of cell based grafts combined with bone extenders to autologous bone grafts.

SUMMARY OF BACKGROUND DATA

Alternative graft options that combine mesenchymal stem cells (MSCs) and bone marrow aspirate (BMA) with synthetic or allograft scaffolds have been recently used in several animal and clinical studies.

METHODS

This systematic review of the literature addresses the following key questions (KQs): (1) Does the use of MSCs or BMA combined with synthetic or allograft extenders contribute to thoracolumbar fusion rates that are comparable with the rates achieved by the use of iliac crest graft? (2) Are these fusion rates comparable with those of local bone graft (LBG)? (3) Does the addition of MSCs or BMA to iliac crest bone graft or LBG contribute to better throracolumbar fusion rates? (4) Are the cervical spine fusion outcomes achieved by the use of SCM or BMA with synthetic or allograft scaffolds comparable with the iliac crest bone graft or LBG outcomes? (5) Was there any difference in terms of fusion rates, when MSCs were compared with BMA?

RESULTS

For KQ1, 4 level II, III studies used iliac crest bone graft as control. The results of these studies were inconsistent, and the overall body of evidence was found insufficient. Three, level II, III studies were identified for KQ2. Comparable fusion rates were demonstrated between LBG and BMA combined with calcium phosphate or collagen carrier. The overall body of evidence was found weak. For KQ3, one level III study was found. No significant difference was found in the fusion rates. No studies met the criteria for KQ4, 5.

CONCLUSION

The currently available evidence is insufficient to support the use of MSCs or BMA combined with synthetic or allograft materials as a substitute or supplementary graft to autologous bone graft.

LEVEL OF EVIDENCE

2.

Bony defect repair in rabbit using hybrid rapid prototyping polylactic-co-glycolic acid/β-tricalciumphosphate collagen I/apatite scaffold and bone marrow mesenchymal stem cells

BACKGROUND

In bone tissue engineering, extracellular matrix exerts critical influence on cellular interaction with porous biomaterial and the apatite playing an important role in the bonding process of biomaterial to bone tissue. The aim of this study was to observe the therapeutic effects of hybrid rapid prototyping (RP) scaffolds comprising polylactic-co-glycolic acid (PLGA), β-tricalciumphosphate (β-TCP), collagen I and apatite (PLGA/β-TCP-collagen I/apatite) on segmental bone defects in conjunction with combination with bone marrow mesenchymal stem cells (BMSCs).

MATERIALS AND METHODS

BMSCs were seeded into the hybrid RP scaffolds to repair 15 mm defect in the radius of rabbits. Radiograph, microcomputed tomography and histology were used to evaluate new bone formation.

RESULTS

Radiographic analysis done from 12 to 36 weeks postoperative period demonstrated that new bone formed at the radial defect site and continues to increase until the medullary cavity is recanalized and remodelling is complete. The bone defect remained unconnected in the original RP scaffolds (PLGA/β-TCP) during the whole study. Histological observations conformed to the radiographic images. In hybrid RP scaffold group, woven bone united the radial defect at 12 weeks and consecutively remodeled into lamellar bone 24 weeks postoperation and finally matured into cortical bone with normal marrow cavity after another 12 weeks. No bone formation but connective tissue has been detected in RP scaffold at the same time.

CONCLUSION

Collagen I/apatite sponge composite coating could improve new bone formation in vivo. The hybrid RP scaffold of PLGA/β-TCP skeleton with collagen I/apatite sponge composite coating is a promising candidate for bone tissue engineering.