Understanding the Future Prospects of Synergizing Minimally Invasive Transforaminal Lumbar Interbody Fusion Surgery with Ceramics and Regenerative Cellular Therapies

Application of RhBMP-2 in Percutaneous Endoscopic Posterior Lumbar Interbody Fusion

BACKGROUND

To investigate the application of recombinant human bone morphogenetic protein-2 (RhBMP-2) in Percutaneous Endoscopic Posterior Lumbar Interbody Fusion (PE-PLIF).

MATERIALS AND METHODS

The study randomly included 102 patients with lumbar spondylosis who underwent PE-PLIF at our hospital from April 2020 to August 2022. Following the random number table method, these subjects were graded as a study group of 51 cases and a control group of 51 cases. Posterior pedicle screw fixation treatment with RhBMP-2 or autologous bone was given respectively. The surgical status and perioperative complications, as well as lumbar spine function before surgery and at 1 and 12 months after surgery [Prolo score and Japanese Orthopaedic Association (JOA) score] of patients in the two groups were observed, and the postoperative fusion rate and cage displacement rate at 1 and 12 months after surgery were compared between the two groups. The degree of vertebral body slippage, intervertebral space height, and changes in quality of life were compared between the two groups before and 12 months after surgery.

RESULTS

There was no significant difference in hospital stay, surgical time, bleeding volume, and incidence of complications between the two groups (P > 0.05)0.12 months post-operation, the Prolo and JOA scores of both groups largely increased, which were significantly higher in the RhBMP-2 group than the control (P < 0.05). 12 months post-operation, the fusion rate in the RhBMP-2 group was 86.27%, which was significantly higher than that of 54.90% in the control group (P < 0.05). 12 months post-operation, the Cage displacement rate in the RhBMP-2 group was 5.88%, which was lower than that of 21.57% in the control group (P < 0.05). 12 months post-operation, the height of the intervertebral space in both groups largely increased, which was significantly higher in the RhBMP-2 group than in the control (P < 0.05). The degree of vertebral body slippage was significantly reduced in both groups, and the RhBMP-2 group was significantly lower than the control (P < 0.05). The cognitive function, social function, physiological function, and mental health were evidently improved in both groups 12 months post-operation and were significantly higher in the RhBMP-2 group than in the control (P < 0.05).

CONCLUSION

RhBMP-2 material in PE-PLIF could significantly restore lumbar function, promote postoperative fusion, reduce Cage displacement and vertebral slippage, accelerate recovery of lumbar intervertebral space, and improve patient quality of life.

Biphasic Calcium Phosphate Bone Graft With a Unique Surface Topography: A Single-Center Ambispective Study for Degenerative Disease of the Lumbar Spine

STUDY DESIGN

This study is an ambispective evaluation and analysis of a single-center cohort.

OBJECTIVE

This study aimed to evaluate the performance of a novel biphasic calcium phosphate (BCP) bone graft with submicron-sized needle-shaped surface topography (BCP<µm) in interbody arthrodesis of the lumbar spine.

METHODS

This study was a single-center ambispective assessment of adult patients receiving BCP<µm as part of their lumbar interbody fusion surgery. The primary outcome was a fusion status on computed tomography (CT) 12 months postoperative. The secondary outcomes included postoperative changes in the visual analog scale (VAS), Oswestry Disability Index (ODI), Short Form 12 (SF-12), and length of stay (LOS).

RESULTS

Sixty-three patients with one- to three-level anterior (48, 76%) and lateral (15, 24%) interbody fusions with posterior instrumentation were analyzed. Thirty-one participants (49%) had three or more comorbidities, including heart disease (43 participants, 68%), obesity (31 participants, 49%), and previous lumbar surgery (23 participants, 37%). The mean ODI decreased by 24. The mean SF-12 physical health and SF-12 mental health improved by a mean of 11.5 and 6.3, respectively. The mean VAS for the left leg, right leg, and back improved by a mean of 25.75, 22.07, and 37.87, respectively. Of 101 levels, 91 (90%) demonstrated complete bridging trabecular bone fusion with no evidence of supplemental fixation failure.

CONCLUSION

The data of BCP<µm in interbody fusions for degenerative disease of the lumbar spine provides evidence of fusion in a complicated cohort of patients.

The bone morphogenetic protein 2 analogue L51P enhances spinal fusion in combination with BMP2 in an in vivo rat tail model

Bone morphogenic protein 2 (BMP2) is known to induce osteogenesis and is applied clinically to enhance spinal fusion despite adverse effects. BMP2 needs to be used in high doses to be effective due to the presence of BMP2 inhibitors. L51P is a BMP2 analogue that acts by inhibition of BMP2 inhibitors. Here, we hypothesized that mixtures of BMP2 and L51P could achieve better spinal fusion outcomes regarding ossification. To test whether mixtures of both cytokines are sufficient to improve ossification, 45 elderly Wistar rats (of which 21 were males) were assigned to seven experimental groups, all which received spinal fusion surgery, including discectomy at the caudal 4-5 level using an external fixator and a porous β-tricalcium phosphate (βTCP) carrier. These βTCP carriers were coated with varying concentrations of BMP2 and L51P. X-rays were taken immediately after surgery and again six and twelve weeks post-operatively. Histological sections and µCT were analyzed after twelve weeks. Spinal fusion was assessed using X-ray, µCT and histology according to the Bridwell scale by voxel-based quantification and a semi-quantitative histological score, respectively. The results were congruent across modalities and revealed high ossification for high-dose BMP2 (10 µg), while PBS induced no ossification. Low-dose BMP2 (1 µg) or 10 µg L51P alone did not induce relevant bone formation. However, all combinations of low-dose BMP2 with L51P (1 µg + 1/5/10 µg) were able to induce similar ossificationas high-dose BMP2. These results are of high clinical relevance, as they indicate L51P is sufficient to increase the efficacy of BMP2 and thus lower the required dose for spinal fusion. STATEMENT OF SIGNIFICANCE: Spinal fusion surgery is frequently applied to treat spinal pathologies. Bone Morphogenic Protein-2 (BMP2) has been approved by the U .S. Food and Drug Administration (FDA-) and by the "Conformité Européenne" (CE)-label. However, its application is expensive and high concentrations cause side-effects. This research targets the improvement of the efficacy of BMP2 in spinal fusion surgery.

Osteobiologies for Spinal Fusion from Biological Mechanisms to Clinical Applications: A Narrative Review

Degenerative lumbar spinal disease (DLSD), including spondylolisthesis and spinal stenosis, is increasing due to the aging population. Along with the disease severity, lumbar interbody fusion (LIF) is a mainstay of surgical treatment through decompression, the restoration of intervertebral heights, and the stabilization of motion segments. Currently, pseudoarthrosis after LIF is an important and unsolved issue, which is closely related to osteobiologies. Of the many signaling pathways, the bone morphogenetic protein (BMP) signaling pathway contributes to osteoblast differentiation, which is generally regulated by SMAD proteins as common in the TGF-β superfamily. BMP-2 and -4 are also inter-connected with Wnt/β-catenin, Notch, and FGF signaling pathways. With the potent potential for osteoinduction in BMP-2 and -4, the combination of allogenous bone and recombinant human BMPs (rhBMPs) is currently an ideal fusion material, which has equalized or improved fusion rates compared to traditional materials. However, safety issues in the dosage of BMP remain, so overcoming current limitations will provide significant advancement in spine surgery. In the future, translational research and the application of clinical study will be important to overcome the current limitations of spinal surgery.

Concepts of Regeneration for Spinal Diseases in 2023

It is our pleasure to announce the publication of the Special Issue "Regeneration for Spinal Diseases 3.0" in the International Journal of Molecular Sciences (ISSN 1422-0067) [...].

History and Evolution of the Minimally Invasive Transforaminal Lumbar Interbody Fusion

The minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) is a popular surgical technique for lumbar arthrodesis, widely considered to hold great efficacy while conferring an impressive safety profile through the minimization of soft tissue damage. This elegant approach to lumbar stabilization is the byproduct of several innovations throughout the past century. In 1934, Mixter and Barr's paper in the New England Journal of Medicine elucidated the role of disc herniation in spinal instability and radiculopathy, prompting surgeons to explore new approaches and instruments to access the disc space. In 1944, Briggs and Milligan published their novel technique, the posterior lumbar interbody fusion (PLIF), involving continuous removal of vertebral bone chips and replacement of the disc with a round bone peg. The following decades witnessed several PLIF modifications, including the addition of long pedicle screws. In 1982, Harms and Rolinger sought to redefine the posterior corridor by approaching the disc space through the intervertebral foramen, establishing the transforaminal lumbar interbody fusion (TLIF). In the 1990s, lumbar spine surgery experienced a paradigm shift, with surgeons placing increased emphasis on tissuesparing minimally invasive techniques. Spurred by this revolution, Foley and Lefkowitz published the novel MIS-TLIF technique in 2002. The MIS-TLIF has demonstrated comparable surgical outcomes to the TLIF, with an improved safety profile. Here, we present a view into the history of the posterior-approach treatment of the discogenic radiculopathy, culminating in the MIS-TLIF. Additionally, we evaluate the hallmark characteristics, technical variability, and reported outcomes of the modern MIS-TLIF and take a brief look at technologies that may define the future MIS-TLIF.

Pretreatment of nucleus pulposus mesenchymal stem cells with appropriate concentration of H2O2 enhances their ability to treat intervertebral disc degeneration

Background

Nucleus pulposus mesenchymal stem cells (NPMSCs) transplantation is a promising treatment for intervertebral disc degeneration (IVDD). However, the transplanted NPMSCs exhibited weak cell proliferation, high cell apoptosis, and a low ability to resist the harsh microenvironment of the degenerated intervertebral disc. There is an urgent need to explore feasible methods to enhance the therapeutic efficacy of NPMSCs transplantation.

Objective

To identify the optimal concentration for NPMSCs pretreatment with hydrogen peroxide (H₂O₂) and explore the therapeutic efficacy of NPMSCs transplantation using H₂O₂ pretreatment in IVDD.

Methods

Rat NPMSCs were pretreated with different concentrations (range from 25 to 300 μM) of H₂O₂. The proliferation, reactive oxygen species (ROS) level, and apoptosis of NPMSCs were detected by cell counting kit-8 (CCK-8) assay, 5-ethynyl-2′-deoxyuridine (EdU) staining, and flow cytometry in vitro. The underlying signalling pathways were explored utilizing Western blotting. A rat needle puncture-stimulated IVDD model was established. X-ray, histological staining, and a multimode small animal live imaging system were used to evaluate the therapeutic effect of H₂O₂-pretreated NPMSCs in vivo.

Results

NPMSCs pretreated with 75 μM H₂O₂ demonstrated the strongest elevated cell proliferation by inhibiting the Hippo pathway (P < 0.01). Meanwhile, 75 μM H₂O₂-pretreated NPMSCs exhibited significantly enhanced antioxidative stress ability (P < 0.01), which is related to downregulated Brd4 and Keap1 and upregulated Nrf2. NPMSCs pretreated with 75 μM H₂O₂ also exhibited distinctly decreased apoptosis (P < 0.01). In vivo experiments verified that 75 μM H₂O₂-pretreated NPMSCs-transplanted rats exhibited an enhanced disc height index (DHI% = 90.00 ± 4.55, P < 0.01) and better histological morphology (histological score = 13.5 ± 0.5, P < 0.01), which means 75 μM H₂O₂-pretreated NPMSCs can better adapt to the environment of degenerative intervertebral discs and promote the repair of IVDD.

Conclusions

Pretreatment with 75 μM H₂O₂ was the optimal concentration to improve the proliferation, antioxidative stress, and antiapoptotic ability of transplanted NPMSCs, which is expected to provide a new feasible method to improve the stem cell therapy efficacy of IVDD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-022-03031-7.

Application and thinking of minimally invasive transforaminal lumbar interbody fusion in degenerative lumbar diseases

Background

This study sought to investigate the clinical efficacy and safety of minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) in the treatment of lumbar degenerative diseases.

Methods

The clinical data of 55 patients with lumbar degenerative diseases treated at our hospital from January 2018 to January 2020 were analyzed retrospectively. Of the 55 patients, 35 who underwent MIS-TLIF were included in the MIS-TLIF group, and 20 who underwent posterior lumbar interbody fusion (PLIF) were included in the PLIF group. The visual analogue scale (VAS) score, Oswestry disability index (ODI) score, operation time, incision length, intraoperative bleeding, postoperative drainage, postoperative landing time, postoperative hospital stay, postoperative interbody fusion rate, and complications were compared between the two groups.

Results

The patients in both groups were followed-up for at least 1.5 years (range, 18–30 months; with an average of 27.5±2.6 months). There was no significant difference in the operation time, incision length, intraoperative bleeding, VAS score for low back and leg pain, ODI score, interbody fusion rate, hospitalization expenses, and complication rate between the two groups (P>0.05). One patient had nail failure in the MIS-TLIF group, 1 patient in each group had nerve root irritation, and 1 patient in each group had superficial incision infection and local suture dehiscence. The postoperative drainage volume, postoperative landing time, and postoperative hospital stay of the MIS-TLIF group were less than those of the PLIF group (P<0.05).

Conclusions

Compared to PLIF, the use of MIS-TLIF in the treatment of lumbar degenerative diseases has a number of advantages, including more complete intraoperative hemostasis, less postoperative drainage, earlier landing, and faster discharge, and also significantly improves postoperative lumbar discomfort.