Comparing the process of creeping substitution between allograft bone and local bone grafting in lumbar interbody fusion

Vascular study of decellularized porcine long bones: Characterization of a tissue engineering model

INTRODUCTION

Massive bone allografts enable the reconstruction of critical bone defects in numerous conditions (e.g. tumoral, infection or trauma). Unfortunately, their biological integration remains insufficient and the reconstruction may suffer from several postoperative complications. Perfusion-decellularization emerges as a tissue engineering potential solution to enhance osseointegration. Therefore, an intrinsic vascular study of this novel tissue engineering tool becomes essential to understand its efficacy and applicability.

MATERIAL AND METHODS

32 porcine long bones (humeri and femurs) were used to assess the quality of their vascular network prior and after undergoing a perfusion-decellularization protocol. 12 paired bones were used to assess the vascular matrix prior (N = 6) and after our protocol (N = 6) by immunohistochemistry. Collagen IV, Von Willebrand factor and CD31 were targeted then quantified. The medullary macroscopic vascular network was evaluated with 12 bones: 6 were decellularized and the other 6 were, as control, not treated. All 12 underwent a contrast-agent injection through the nutrient artery prior an angio CT-scan acquisition. The images were processed and the length of medullary vessels filled with contrast agent were measured on angiographic cT images obtained in control and decellularized bones by 4 independent observers to evaluate the vascular network preservation. The microscopic cortical vascular network was evaluated on 8 bones: 4 control and 4 decellularized. After injection of gelatinous fluorochrome mixture (calcein green), non-decalcified fluoroscopic microscopy was performed in order to assess the perfusion quality of cortical vascular lacunae.

RESULTS

The continuity of the microscopic vascular network was assessed with Collagen IV immunohistochemistry (p-value = 0.805) while the decellularization quality was observed through CD31 and Von Willebrand factor immunohistochemistry (p-values <0.001). The macroscopic vascular network was severely impaired after perfusion-decellularization; nutrient arteries were still patent but the amount of medullary vascular channels measured was significantly higher in the control group compared to the decellularized group (p-value <0.001). On average, the observers show good agreement on these results, except in the decellularized group where more inter-observer discrepancies were observed. The microscopic vascular network was observed with green fluoroscopic signal in almost every canals and lacunae of the bone cortices, in three different bone locations (proximal metaphysis, diaphysis and distal metaphysis).

CONCLUSION

Despite the aggressiveness of the decellularization protocol on medullary vessels, total porcine long bones decellularized by perfusion retain an acellular cortical microvascular network. By injection through the intact nutrient arteries, this latter vascular network can still be used as a total bone infusion access for bone tissue engineering in order to enhance massive bone allografts prior implantation.

Structural Versus Nonstructural Bone Grafting Via the Posterior Approach in the Treatment of Thoracic and Lumbar Tuberculosis: A Systematic Review and Meta-Analysis

BACKGROUND

Bone grafting is necessary in spinal tuberculosis surgery. Structural bone grafting is considered the gold standard treatment for spinal tuberculosis bone defects; however, nonstructural bone grafting via the posterior approach has recently gained attention. In this meta-analysis, we evaluated the clinical efficacy of structural versus nonstructural bone grafting via the posterior approach in the treatment of thoracic and lumbar tuberculosis.

METHODS

Studies comparing the clinical efficacy of structural and nonstructural bone grafting via the posterior approach in spinal tuberculosis surgery were identified from 8 databases from inception to August 2022. Study selection, data extraction, and evaluation of the risk of bias were performed, and meta-analysis was conducted.

RESULTS

Ten studies including 528 patients with spinal tuberculosis were enrolled. Meta-analysis revealed no between-group differences in fusion rate (P = 0.29), complications (P = 0.21), postoperative Cobb angle (P = 0.7), visual analog scale score (P = 0.66), erythrocyte sedimentation rate (P = 0.74), or C-reactive protein level (P = 0.14) at the final follow-up. Nonstructural bone grafting was associated with less intraoperative blood loss (P < 0.00001), shorter operation time (P < 0.0001), shorter fusion time (P < 0.01), and shorter hospital stay (P < 0.00001), while structural bone grafting was associated with lower Cobb angle loss (P = 0.002).

CONCLUSIONS

Both techniques can achieve a satisfactory bony fusion rate for spinal tuberculosis. Nonstructural bone grafting has the advantages of less operative trauma, shorter fusion time, and shorter hospital stay, making it an attractive option for short-segment spinal tuberculosis. Nevertheless, structural bone grafting is superior for maintaining corrected kyphotic deformities.

Oblique lumbar interbody fusion combined with stress end plate augmentation and anterolateral screw fixation for degenerative lumbar spinal stenosis with osteoporosis: a matched-pair case-controlled study

BACKGROUND CONTEXT

Oblique lumbar interbody fusion (OLIF) has been proven to be effective in treating degenerative lumbar spinal stenosis (DLSS). Whether OLIF is suitable for treating patients with DLSS with osteoporosis (OP) is still controversial. Bone cement augmentation is widely used to enhance the internal fixation strength of osteoporotic spines. However, the effectiveness of OLIF combined with bone cement stress end plate augmentation (SEA) and anterolateral screw fixation (AF) for DLSS with OP have not confirmed yet.

PURPOSE

To evaluate the clinical, radiological, and functional outcomes of OLIF-AF versus OLIF-AF-SEA in the treatment of DLSS with OP.

STUDY DESIGN

Retrospective case-control study.

PATIENT SAMPLE

A total of 60 patients with OP managed for DLSS at L4-L5.

OUTCOME MEASURES

Visual analog scale (VAS) score of the lower back and leg, Oswestry Disability Index (ODI), disk height (DH), lumbar lordosis (LL), segmental lordosis (SL), cage subsidence and fusion rate.

METHODS

The study was performed as a retrospective matched-pair case‒controlled study. Patients with OP managed for DLSS at L4-L5 between October 2017 and June 2020 and completed at least 2 years of follow-up were included, which were 30 patients treated by OLIF-AF and 30 patients undergoing OLIF-AF-SEA. The demographics and radiographic data, fusion status and functional outcomes were therefore compared to evaluate the efficacy of the two approaches.

RESULTS

Pain and disability improved similarly in both groups at the 24-month follow-up. However, the SEA group had lower pain and functional disability at 3 months postoperatively (p<.05). The mean postoperative disc height decrease (△DH) was significantly lower in the SEA group than in the control group (1.17±0.81 mm vs 2.89±2.03 mm; p<.001). There was no significant difference in lumbar lordosis (LL) or segmental lordosis (SL) between the groups preoperatively and 1 day postoperatively. However, a statistically significant difference was observed in SL and LL between the groups at 24 months postoperatively (p<.05). CS was observed in 4 cases (13.33%) in the SEA group and 17 cases (56.67%) in the control group (p<.001). A nonsignificant difference was observed in the fusion rate between the SEA and control groups (p=.347) at 24 months postoperatively.

CONCLUSIONS

This study revealed that OLIF-AF-SEA was safe and effective in the treatment of DLSS with OP. Compared with OLIF-AF, OLIF-AF-SEA results in a minor postoperative disc height decrease, a lower rate of CS, better sagittal balance, and no adverse effect on interbody fusion.

Biomaterials for Interbody Fusion in Bone Tissue Engineering

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

PLIF surgery with titanium-coated PEEK or uncoated PEEK cages: a prospective randomised clinical and radiological study

PURPOSE

This study aimed to compare clinical results and fusion rates of uncoated polyetheretherketone (PEEK) cages with titanium-coated PEEK cages in posterior lumbar interbody fusion (PLIF) surgery.

METHODS

A prospective randomised study including 60 patients with one- or two-segment lumbar degenerative diseases. Patients received either titanium-coated PEEK cages (group A) or uncoated PEEK cages (group B). Fusion rates were evaluated on plain X-rays and CT scans after 6 and 12 months. Clinical follow-up (visual analogue scale, VAS; Oswestry Disability Index score, ODI; EQ-5D) was performed for 24 months.

RESULTS

Fifty-five patients (92%) (36 female, 19 male) had a complete follow-up. There were no statistically significant differences in demographic, peri- or intraoperative data between groups A and B. ODI, VAS and EQ-5D improved significantly (p < 0.001) after surgery without statistically significant differences between the two groups. Overall, 65 operated segments could be evaluated for fusion (group A: 29 segments, group B: 36 segments, p = 0.6). Osseous integration of the cage surface improved significantly (p < 0.001) in both groups between 6 and 12 months after surgery. At 12-month follow-up, neither radiolucency nor signs of instability or dislocation were noted. Fusion was present in CT scans as follows: (a) bone growth through cage pores (A: 100%, B: 100%); (b) bone growth outside the cages (A: 48%, B: 61%; p = 0.3).

CONCLUSIONS

PEEK and titanium-coated PEEK cages for PLIF produce equally favourable clinical and radiological results up to 24 months post-surgery. The fusion rate was not different.

Efficacy and safety of bone substitutes in lumbar spinal fusion: a systematic review and network meta-analysis of randomized controlled trials

PURPOSE

A variety of alternative grafts to autologous iliac crest bone (ICBG) have been developed for lumbar spondylodesis, due to frequent complications following ICBG harvest. The optimal alternative graft to ICBG, however, remains elusive till now. The purpose of this study was to compare the efficacy and safety of fusion materials in lumbar degeneration diseases and to provide a ranking spectrum of the grafts.

METHODS

Randomized controlled trials (RCTs) comparing different bone grafts in lumbar arthrodesis were eligible for inclusion. A network meta-analysis was performed for endpoints including fusion rate and incidence of adverse events.

RESULTS

Twenty-seven RCTs involving 2488 patients and 13 available interventions were included. rhBMP-2 provided the highest fusion rate, being significantly superior to that of ICBG (OR = 0.21, p < 0.001), autograft local bone (ALB) (OR = 0.18, p = 0.022), rhBMP-7 (OR = 0.15, p < 0.001), allograft (OR = 0.13, p = 0.009), and DBM + ALB (OR = 0.07, p = 0.048). The treatment efficacy of allograft could be significantly enhanced by bone marrow concentrate (BMC) supplying (OR = 0.16, p = 0.010). ICBG ranks second on the frequency of complications, which is significantly higher than that of allograft (OR = 0.14, p = 0.041) and ALB (OR = 0.14, p = 0.030). All of the other comparisons showed similar efficacy and safety profiles between groups.

CONCLUSION

Ranking spectrums of the efficacy and safety for various bone grafts were provided graphically. Though rhBMP-2 was of the highest success rate, the application should be taken with proper caution because of the widely proposed life-threatening adverse events. ALB, ALB plus synthetic ceramic materials and allograft mixed with BMC were also proved to be potentially effective alternative graft to ICBG. These slides can be retrieved under Electronic Supplementary Material.

Comparison of Clinical and Radiological Outcomes of Lumbar Interbody Fusion Using a Combination of Hydroxyapatite and Demineralized Bone Matrix and Autografts for Lumbar Degenerative Spondylolisthesis

Study Design

Prospective, cohort, non-inferiority study.

Purpose

This study evaluated the clinical and radiological outcomes of interbody fusion using a combination of demineralized bone matrix (DBM) and hydroxyapatite (HA).

Overview of Literature

The use of autografts remains a gold standard in lumbar interbody fusion, but the limited availability and donor site morbidity encourages the use of bone substitutes. In addition to autografts, a combination of HA and DBM is being increasingly use for lumbar interbody fusion. However, there are no data on the clinical and radiological outcomes of this procedure.

Methods

We examined 35 patients with lumbar degenerative spondylolisthesis who underwent transforaminal interbody fusion. Autografts were used in 18 patients, and 17 patients received a combination of HA and DBM. Clinical outcomes were evaluated using the visual analog scale (VAS) for back and leg pain, Oswestry disability index (ODI), and Japanese Orthopaedic Association (JOA) scores at 3, 6, and 12 months postoperatively. Fusion was evaluated using computed tomography images obtained at 12 months postoperatively.

Results

The mean ODI, JOA, and back and leg pain VAS scores increased significantly in both groups. However, the VAS, JOA, and ODI scores did not differ significantly between the two groups (p=0.599, p=0.543, and p=0.780, respectively). The fusion rates at 1 year postoperatively were 77.8% and 76.5% in the autograft and HA+DBM groups, respectively (p=0.99).

Conclusions

The clinical and radiological outcomes of using a combination of HA and DBM in lumbar interbody fusion were not inferior to those of using autografts. A combination of HA and DBM can be considered as an alternative in patients with lumbar degenerative spondylolisthesis requiring surgery.

Comparative effectiveness of two different interbody fusion methods for transforaminal lumbar interbody fusion: cage versus morselized impacted bone grafts

Background

The use of an interbody fusion device (cage) to assist fusion and increase intervertebral stability is widely supported. We applied the morselized impacted bone graft method without using a cage in a single level interbody fusion with encouraging medium-term clinical results. The purpose of this paper is to compare the clinical and radiological results of local bone grafts with a cage to morselized impacted bone grafts without cage, in patients undergoing transforaminal lumbar interbody fusion (TLIF) surgery.

Methods

One hundred eighty-nine consecutive patients who underwent TLIF in our hospital were evaluated from July 2009 to July 2012. Eighty-four patients received TLIF and local bone graft with one polyetheretherketone (PEEK) cage, while 96 patients received the TLIF with local morselized impacted bone grafts without a cage. The clinical data and perioperative parameters of the patients in the two groups were recorded and compared.

Results

The mean follow-up time was 35 months. There were no significant differences in operation time and blood loss between the two groups. Single-level fusion was performed in all patients. There were no statistically significant differences between the two groups, according to the preoperative or postoperative Oswestry Disability Index (ODI) score. No statistically significant differences in fusion rate were observed between the two groups. At the final follow-up, the ratio of the disc height to vertebral height (HR) was not significantly different between the two groups.

Conclusion

Morselized impacted bone graft is as beneficial as local bone grafts with a cage for TLIF. Since the no cage procedure is less expensive, the morselized impacted bone graft is an affordable choice for single level TLIF, especially in less developed regions.