Failure in Lumbar Spinal Fusion and Current Management Modalities

Exploring an innovative augmentation strategy in spinal fusion: A novel selective prostaglandin EP4 receptor agonist as a potential osteopromotive factor to enhance lumbar posterolateral fusion

BACKGROUND

On-site delivery of bioactive agents facilitates enhancing the effectiveness of spinal fusion. However, the FDA-approved agents currently used in clinical practice are limited by side effects and cost issues, urging exploration of new alternatives.

AIM

This study aimed to investigate the effectiveness of KMN-159, a novel selective prostaglandin EP4 receptor agonist with osteopromotive properties, in spinal posterolateral fusion (PLF) surgery.

METHODS

Various doses of KMN-159 were delivered locally using a mineralized collagen matrix (MCM) scaffold, and its efficacy results were compared with FDA-approved recombinant human bone morphogenetic protein-2 (rhBMP-2) in a rat lumbar PLF model. 192 male Wistar rats, aged 10 weeks, were randomized into 8 groups: 1) SHAM, 2) MCM, 3) MCM +10 μg rhBMP-2 (per scaffold), 4-8) MCM + 0.1, 1, 10, 100 or 1000 μg KMN-159 (per scaffold). PLF surgery was performed at the L4-5 level, and animals were euthanized after 3 and 6 weeks for spinal fusion evaluation.

RESULTS

KMN-159 exhibited dose-dependent osteopromotive effects on osteoblasts, osteoclasts, and vascular ingrowth within MCM carriers, resulting in new bone formation in a dose-dependent manner. The mid- and high-dose KMN-159 (10, 100, and 1000 μg) groups significantly enhanced PLF with biomechanical improvement, while low-dose (0.1 and 1 μg) groups were insufficient to achieve lumbar fusion.

CONCLUSION

KMN-159 emerges as a novel osteopromotive factor, coupled with its functionalized MCM scaffold presents a potential bioactive material for enhancing PLF surgery outcomes.

Fusion Rate of Biphasic Calcium Phosphate Bone Graft with Needle-Shaped Submicron Surface Topography in Interbody Lumbar Fusion for Degenerative Disc Disease: A Single-Center Retrospective Review

BACKGROUND

Calcium phosphate bone grafts are emerging as alternatives to autologous bone grafts in lumbar spinal fusion. This study evaluates the 12-month fusion rate and clinical outcomes of lumbar interbody fusion using synthetic biphasic calcium phosphate with submicron needle-shaped surface topography (BCP<μm).

METHODS

A retrospective review identified patients who underwent lumbar interbody arthrodesis with BCP<μm, with or without autograft. Fusion was assessed by an independent neuroradiologist using a computed tomography alphanumeric classification based on bridging bone on 12-month postoperative computed tomography. Secondary outcomes included changes in visual analog scale, length of stay, and fusion of all treated levels.

RESULTS

Fifty-five patients with 93 treated levels were analyzed (average age: 62.78 years; body mass index: 28.73 kg/m2). Patients had an average of 3 comorbidities and a median of 2 levels fused. Procedures included anterior (52 levels), transforaminal (22 levels), and lateral lumbar interbody fusion (19 levels). Fusion occurred in 95.70% of levels without evidence of fixation failure. Fusion rates were unaffected by procedure type (P = 0.965) or supplemental autograft use (P = 1.00). Complications were reported in 4 patients. Six-month postoperative visual analog scale improved by a mean of 25.10 (P < 0.0001).

CONCLUSIONS

This study demonstrates a high fusion rate (95.70%) and low complication rate in a diverse patient population with multiple comorbidities, suggesting BCP<μm is a viable graft material for lumbar interbody fusion.

Evaluating the Association Between Physical Therapy Variables and Outcomes After Lumbar Fusion

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

The purpose of this study was to investigate how inpatient physical therapy variables impact (1) inpatient complications, (2) 90-day readmissions, (3) 1-year reoperation rates, and (4) length of stay after posterior lumbar decompression and fusion.

SUMMARY OF BACKGROUND DATA

Previous studies have emphasized the role of early ambulation in postoperative spine patients as an effective method for improving pain and decreasing length of stay, but few studies have evaluated the efficacy of inpatient physical therapy.

METHODS

Patients 18 years of age or older who underwent primary 1-level or 2-level posterior lumbar decompression and fusion from 2019 to 2020 were retrospectively identified. Physical therapy data, including time to first inpatient PT session, gait trial distance achieved, post-treatment pain rating, and Activity Measure for Post-Acute Care (Activity Measure for Post-Acute Care [AM-PAC]) scores were collected using manual chart review. Surgical outcome variables included length of stay, inpatient complications, 90-day readmissions, and reoperations within 1 year of primary surgery.

RESULTS

Overall, 425 patients were identified. There was no difference in hours to PT or total gait trial distance achieved between patients who experienced a complication and those that did not. Patients in the noncomplication group had higher AM-PAC scores than patients in the complication group. There was no difference with regards to time to PT, AM-PAC score, or gait trial distance achieved between readmitted patients and nonreadmitted patients or revision patients and nonrevision patients. Stepwise logistic regression showed that having a physical therapy session within 6 hours of surgery was predictive of a decreased length of stay both in all patients.

CONCLUSIONS

While inpatient physical therapy within 6 hours of surgery does not appear to impact readmissions, complications, or reoperations, surgeons should encourage early ambulation postoperatively to decrease extended hospital stays. Future investigation should seek to identify factors that delay inpatient PT in the 6 hours after surgery.

Prospective cohort study of basivertebral nerve ablation for chronic low back pain in a real-world setting: 12 months follow-up

Background

The basivertebral nerve, which densely supplies the vertebral endplates, is a potential source of chronic low back pain transmission in patients with Modic changes. Basivertebral nerve ablation (BVNA), a minimally invasive procedure, aims to disrupt this pain signaling.

Objectives

In this study, we investigated BVNA's effectiveness in treatment of vertebrogenic low back pain and we followed patients for 12 months to assess long-term effectiveness.

Study design

Single group prospective cohort study (ClinicalTrials.gov NCT05692440).

Setting

Single-center, community private practice.

Methods

Thirty-five patients were treated with the INTRACEPT® device (Boston Scientific, MA, USA). Thirty-one patients completed Oswestry Disability Index (ODI), Visual Analog Scale (VAS), SF-36 Physical Component Summary (PCS), and SF-36 Mental Component Summary (MCS) at baseline and follow-up visits up to 12 months.

Results

The average age of the 31 patients was 73.0 ± 6.34 years and 71.0 % of the population was male (N=22)) at baseline. All four self-reported outcomes (ODI, VAS, SF-36 PCS, and MCS) showed statistically and clinically significant improvements from baseline through 12 months (all p < 0.001, with the exception of the SF-36 MCS at 1 month, p = 0.165). Overall, 67.7 % of patients demonstrated ODI improvements above the minimal clinically important difference (decrease of at least 15 points) and 77.4 % of patients demonstrated a decrease on the VAS above the minimal clinically important difference (≥2 cm reduction) at 12 months.

Limitations

Limitations of the study include the lack of a control group and potentially unintentional bias in patient selection.

Conclusions

BVNA demonstrates potential as an effective and minimally invasive treatment for chronic low back pain in a real-world patient cohort where substantial improvements were observed. These results align with those seen in previous randomized controlled trials (RCTs) and industry-funded studies of BVNA.

The effect of radiotherapy, chemotherapy, and immunotherapy on fusion rate in spinal surgery using osteobiologics for patients with metastatic spinal disease: a systematic review

OBJECTIVE

To evaluate the impact that adjuvant therapies like radiotherapy, chemotherapy, and immunotherapy have on osteobiologic properties and bony regeneration in patients with metastatic spine disease (MSD) undergoing spinal fusion surgery.

METHODS

PubMed and ClinicalTrials.gov searches were performed. MSD patients undergoing fusion surgery with an osteobiologic and radiotherapy, chemotherapy and/or immunotherapy were included. Demographics, primary tumor, surgery, adjuvant treatments, osteobiologic type, fusion rates with scoring criteria, hardware failure, reoperation rates, follow-up, and survival were extracted. 1487 studies were screened, 20 included.

RESULTS

585 patients (464 with MSD) had fusion rates ranging from 17.9 to 100%. In the setting of radiotherapy, fusion rates of 10 studies using autologous bone graft (autograft), 5 studies using allogenic bone graft (allograft), 5 studies using combination autograft/allograft, 4 studies using biomaterial scaffolds (BMS), 3 studies using demineralized bone matrices (DBM), and 1 study using growth factors (GF), were 50-100%, 17.9-100%, 57.8-100%, 52.9-100%, 20-100%, and 100%, respectively. A higher incidence of fusion in patients with autograft or allograft receiving stereotactic body radiotherapy (SBRT) at lower biologically effective doses (BED) and at least 1-month postoperatively was noted. Chemotherapy had no impact on fusion. No studies evaluated the impact of immunotherapy on fusion.

CONCLUSIONS

SBRT at lower doses given greater than 1-month postoperatively may enhance bony fusion in patients receiving autograft, allograft, or autograft/allograft. Chemotherapy may delay bony fusion without affecting overall fusion rates. Preclinical studies suggest immunotherapy may prevent osteolysis and promote osteogenesis, but no studies have yet evaluated the clinical impact of these findings on spinal fusion. Further research is needed on osteobiologics in bony regeneration in the MSD population.

Effect of Prior Cheilectomy on Outcomes of First Metatarsophalangeal Joint Fusion

Cheilectomy, a joint-conserving procedure, is often a first-line choice for treating early stages of hallux rigidus. Recent evidence has revealed its efficacy in treating more advanced stages. However, when degeneration is profound, first metatarsophalangeal (MTP) fusion remains the most appropriate strategy. Nevertheless, it is common for surgeons to proceed initially with cheilectomy, reserving joint fusion for subsequent considerations if cheilectomy fails. This article will explore the relationship between the 2 procedures and evaluate the research surrounding the effect of prior cheilectomy on first MTP joint arthrodesis.

An overview of magnesium-based implants in orthopaedics and a prospect of its application in spine fusion

Due to matching biomechanical properties and significant biological activity, Mg-based implants present great potential in orthopedic applications. In recent years, the biocompatibility and therapeutic effect of magnesium-based implants have been widely investigated in trauma repair. In contrast, the R&D work of Mg-based implants in spinal fusion is still limited. This review firstly introduced the general background for Mg-based implants. Secondly, the mechanical properties and degradation behaviors of Mg and its traditional and novel alloys were reviewed. Then, different surface modification techniques of Mg-based implants were described. Thirdly, this review comprehensively summarized the biological pathways of Mg degradation to promote bone formation in neuro-musculoskeletal circuit, angiogenesis with H-type vessel formation, osteogenesis with osteoblasts activation and chondrocyte ossification as an integrated system. Fourthly, this review followed the translation process of Mg-based implants via updating the preclinical studies in fracture fixation, sports trauma repair and reconstruction, and bone distraction for large bone defect. Furthermore, the pilot clinical studies were involved to demonstrate the reliable clinical safety and satisfactory bioactive effects of Mg-based implants in bone formation. Finally, this review introduced the background of spine fusion surgeryand the challenges of biological matching cage development. At last, this review prospected the translation potential of a hybrid Mg-PEEK spine fusion cage design.

High Strength and Shape Memory Spinal Fusion Device for Minimally Invasive Interbody Fusions

INTRODUCTION

Lumbar interbody fusion is widely employed for both acute and chronic spinal diseases interventions. However, large incision created during interbody cage implantation may adversely impair spinal tissue and influence postoperative recovery. The aim of this study was to design a shape memory interbody fusion device suitable for small incision implantation.

METHODS

In this study, we designed and fabricated an intervertebral fusion cage that utilizes near-infrared (NIR) light-responsive shape memory characteristics. This cage was composed of bisphenol A diglycidyl ether, polyether amine D-230, decylamine and iron oxide nanoparticles. A self-hardening calcium phosphate-starch cement (CSC) was injected internally through the injection channel of the cage for healing outcome improvement.

RESULTS

The size of the interbody cage is reduced from 22 mm to 8.8 mm to minimize the incision size. Subsequent NIR light irradiation prompted a swift recovery of the cage shape within 5 min at the lesion site. The biocompatibility of the shape memory composite was validated through in vitro MC3T3-E1 cell (osteoblast-like cells) adhesion and proliferation assays and subcutaneous implantation experiments in rats. CSC was injected into the cage, and the relevant results revealed that CSC is uniformly dispersed within the internal space, along with the cage compressive strength increasing from 12 to 20 MPa.

CONCLUSION

The results from this study thus demonstrated that this integrated approach of using a minimally invasive NIR shape memory spinal fusion cage with CSC has potential for lumbar interbody fusion.

Association Between Preoperative Cannabis Use and Increased Rate of Revision Surgery Following Spinal Fusion: A Systematic Review and Meta-Analysis

The use of cannabis as a method of chronic pain relief has skyrocketed since its legalization in states across the United States. Clinicians currently have a limited scope regarding the effectiveness of marijuana on surgical procedures. This systematic review aims to determine the effect of current cannabis use on the rate of failure of spinal fusions and overall surgical outcomes. A systematic review was performed in accordance with the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) statement. PubMed, Embase, and Scopus were searched, identifying studies assessing spinal fusion with reported preoperative cannabis use. Outcomes of interest included reoperation due to fusion failure or pseudoarthrosis with a follow-up time of at least six months. Subgroups of cervical fusions alone and lumbar fusions alone were also analyzed. Certainty in evidence and bias was assessed using the GRADE criteria and ROBINS-I tool (PROSPERO #CRD42023463548). Four studies met the inclusion criteria, with a total of 788 patients (188 in the cannabis user group and 600 in the non-user group). The rate of revision surgery among cannabis users was higher than that in non-users for all spinal fusions (RR: 3.58, 95% CI: 1.67 to 7.66, p = 0.001). For cervical fusions alone, there remained a higher rate of revision surgery for cannabis users compared to non-users (RR: 4.47, 95% CI: 1.93 to 10.36, p = 0.0005). For lumbar fusions alone, there was no difference in the rates of revision surgery between cannabis users and non-users (RR: 1.21, 95% CI: 0.28 to 7.73, p = 0.79). Cannabis use was shown to be associated with a higher rate of pseudoarthrosis revisions in spinal fusions on meta-analysis. On subgroup stratification by spine region, cannabis use remained associated with pseudoarthrosis revisions on cervical fusions alone but not lumbar fusions alone. Further research with larger, randomized studies is required to fully elucidate the relationship between cannabis use and fusion, both in general and by spinal region.

Postoperative Sclerotic Modic Changes After Transforaminal Lumbar Interbody Fusion: The Prevalence, Risk Factors, and Impact on Fusion

STUDY DESIGN

A retrospective cohort study.

OBJECTIVE

This study aimed to assess postoperative sclerotic modic changes (MCs) following transforaminal lumbar interbody fusion for lumbar degenerative disc disease, investigating their prevalence, risk factors, and association with clinical outcomes.

SUMMARY OF BACKGROUND DATA

Sclerotic MCs may occur in patients with lumbar degenerative disc disease after lumbar interbody fusion. The incidence and characteristics of postoperative sclerotic MCs, as well as their clinical impact, are unknown.

MATERIALS AND METHODS

The study included 467 patients (510 levels) who underwent single or two-level transforaminal lumbar interbody fusion surgery, divided into a postoperative sclerotic MC group (60 patients, 66 levels) and a non-MC group (407 patients, 444 levels). The time of development and location of postoperative sclerotic MCs, fusion rate, cage subsidence, bilateral process decompression, and cross-link usage were recorded. Preoperative, postoperative, and follow-up visual analogue scale and Oswestry disability index scores were collected. Multivariable logistic regression was used to evaluate factors associated with the development of postoperative sclerotic MCs.

RESULTS

The prevalence of postoperative sclerotic MCs was 12.8%. The postoperative sclerotic MC group had a higher body mass index (BMI). The postoperative sclerotic MC group demonstrated a fusion rate of 47%, significantly lower than that of the non-MC group (71%) at six months post-operation. At final follow-up, the fusion rate in the postoperative sclerotic MC group was 62%, significantly lower than that of the non-MC group (86%). Postoperative visual analogue scale and Oswestry disability index scores were significantly higher in the group with postoperative sclerotic MCs. BMI and osteoporosis were significantly associated with the development of postoperative sclerotic MCs.

CONCLUSION

Postoperative sclerotic MCs generally appear within the first year after surgery, with a prevalence of 12.8%. The presence of postoperative sclerotic MCs can adversely impact postoperative outcomes. To prevent postoperative sclerotic MCs, the authors postulate extending the immobilization period with external bracing and improving the management of BMI and osteoporosis in the perioperative time window.

Efficacy and Outcome Measurement of iFactor/ABM/P-15 in Lumbar Spine Surgery: A Systematic Review

STUDY DESIGN

Systematic Review.

OBJECTIVES

To determine the efficacy and overall outcomes of iFactor/ABM/P-15 following lumbar spine surgery.

METHODS

We performed a search of the Cochrane Library, Medline Ovid, PubMed, and SCOPUS databases from inception until August 2023. Eligible studies included outcomes of patients receiving iFactor following lumbar spine surgery. The primary outcomes of interest were fusion rates and iFactor efficacy after lumbar surgery in patients who received iFactor. Secondary outcomes included patient-reported outcomes and complication rates.

RESULTS

A total of 766 titles were initially screened. After inclusion criteria were applied, 5 studies (388 patients) were included, which measured overall outcomes of iFactor/ABM/P-15 following lumbar spine surgery. These studies showed acceptable reliability for inclusion based on the Methodical Index for Non-Randomized studies and Critical Appraisal Skills Programme assessment tools. iFactor/ABM/P-15 facilitated significantly faster bone development in various procedures while maintaining favorable clinical outcomes compared to traditional grafts.

CONCLUSIONS

This systematic review found that iFactor/ABM/P-15 use for lumbar spine surgery maintains similar managing patient-reported outcomes relative to other grafting methods. In regard to rates of fusion, iFactor/ABM/P-15 showed a significantly faster rate of fusion when compared to traditional grafts including allograft, autograft, demineralized bone matrix (DBM), and recombinant human bone morphogenetic protein-2 (rhBMP-2). Future multicenter randomized control trials with larger sample sizes are recommended to further assess iFactor/ABM/P-15 efficacy in lumbar spine surgery.

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.