Effect of Postoperative Analgesic Exposure to the Cannabinoid Receptor Agonist WIN55 on Osteogenic Differentiation and Spinal Fusion in Rats

A Mechanistic and Preclinical Assessment of BioRestore Bioactive Glass as a Synthetic Bone Graft Extender and Substitute for Osteoinduction and Spine Fusion

STUDY DESIGN

Preclinical animal study.

OBJECTIVE

Evaluate the osteoinductivity and bone regenerative capacity of BioRestore bioactive glass.

SUMMARY OF BACKGROUND DATA

BioRestore is a Food and Drug Administration (FDA)-approved bone void filler that has not yet been evaluated as a bone graft extender or substitute for spine fusion.

METHODS

In vitro and in vivo methods were used to compare BioRestore with other biomaterials for the capacity to promote osteodifferentiation and spinal fusion. The materials evaluated (1) absorbable collagen sponge (ACS), (2) allograft, (3) BioRestore, (4) Human Demineralized Bone Matrix (DBM), and (5) MasterGraft. For in vitro studies, rat bone marrow-derived stem cells (BMSC) were cultured on the materials in either standard or osteogenic media (SM, OM), followed by quantification of osteogenic marker genes (Runx2, Osx, Alpl, Bglap, Spp1) and alkaline phosphatase (ALP) activity. Sixty female Fischer rats underwent L4-5 posterolateral fusion (PLF) with placement of 1 of 5 implants: (1) ICBG from syngeneic rats; (2) ICBG+BioRestore; (3) BioRestore alone; (4) ICBG+Allograft; or (5) ICBG+MasterGraft. Spines were harvested 8 weeks postoperatively and evaluated for bone formation and fusion via radiography, blinded manual palpation, microCT, and histology.

RESULTS

After culture for 1 week, BioRestore promoted similar expression levels of Runx2 and Osx to cells grown on DBM. At the 2-week timepoint, the relative ALP activity for BioRestore-OM was significantly higher (P<0.001) than that of ACS-OM and DBM-OM (P<0.01) and statistically equivalent to cells grown on allograft-OM. In vivo, radiographic and microCT evaluation showed some degree of bridging bone formation in all groups tested, with the exception of BioRestore alone, which did not produce successful fusions.

CONCLUSIONS

This study demonstrates the capacity of BioRestore to promote osteoinductivity in vitro. In vivo, BioRestore performed similarly to commercially available bone graft extender materials but was incapable of producing fusion as a bone graft substitute.

LEVEL OF EVIDENCE

Level V.

Silencing p75NTR regulates osteogenic differentiation and angiogenesis of BMSCs to enhance bone healing in fractured rats

BACKGROUND

Fractures heal through a process that involves angiogenesis and osteogenesis but may also lead to non-union or delayed healing. Bone marrow mesenchymal stem cells (BMSCs) have been reported to play a pivotal role in bone formation and vascular regeneration and the p75 neurotrophin receptor (p75NTR) as being an important regulator of osteogenesis. Herein, we aim to determine the potential mediation of BMSCs by p75NTR in bone healing.

METHODS

Rat BMSCs were identified by flow cytometry (FCM) to detect cell cycle and surface markers. Then transfection of si/oe-p75NTR was performed in BMSCs, followed by Alizarin red staining to detect osteogenic differentiation of cells, immunofluorescence double staining was performed to detect the expression of p75NTR and sortilin, co-immunoprecipitation (CO-IP) was conducted to analyze the interaction between p75NTR and sortilin, and EdU staining and cell scratch assay to assess the proliferation and migration of human umbilical vein endothelial cells (HUVECs). The expression of HIF-1α, VEGF, and apoptosis-related proteins were also detected. In addition, a rat fracture healing model was constructed, and BMSCs-si-p75NTR were injected, following which the fracture condition was observed using micro-CT imaging, and the expression of platelet/endothelial cell adhesion molecule-1 (CD31) was assessed.

RESULTS

The results showed that BMSCs were successfully isolated, p75NTR inhibited apoptosis and the osteogenic differentiation of BMSCs, while si-p75NTR led to a decrease in sortilin expression in BMSCs, increased proliferation and migration in HUVECs, and upregulation of HIF-1α and VEGF expression. In addition, an interaction was observed between p75NTR and sortilin. The knockdown of p75NTR was found to reduce the severity of fracture in rats and increase the expression of CD31 and osteogenesis-related proteins.

CONCLUSION

Silencing p75NTR effectively modulates BMSCs to promote osteogenic differentiation and angiogenesis, offering a novel perspective for improving fracture healing.

Management of Postoperative Pain in Patients Following Spine Surgery: A Narrative Review

Perioperative pain management is a unique challenge in patients undergoing spine surgery due to the increased incidence of both pre-existing chronic pain conditions and chronic postsurgical pain. Peri-operative planning and counseling in spine surgery should involve an interdisciplinary approach that includes consideration of patient-level risk factors, as well as pharmacologic and non-pharmacologic pain management techniques. Consideration of psychological factors and patient focused education as an adjunct to these measures is paramount in developing a personalized perioperative pain management plan. Understanding the currently available body of knowledge surrounding perioperative opioid management, management of opioid use disorder, regional/neuraxial anesthetic techniques, ketamine/lidocaine infusions, non-opioid oral analgesics, and behavioral interventions can be useful in developing a comprehensive, multi-modal treatment plan among patients undergoing spine surgery. Although many of these techniques have proved efficacious in the immediate postoperative period, long-term follow-up is needed to define the impact of such approaches on persistent pain and opioid use. Future techniques involving the use of precision medicine may help identify phenotypic and physiologic characteristics that can identify patients that are most at risk of developing persistent postoperative pain after spine surgery.

Prevalence of Cannabinoid (CBD) Use in Orthopaedic Sports Medicine Patients

Background:

Although there is some evidence that cannabinoid (CBD) products may provide a therapeutic effect for musculoskeletal pain, little is known about the usage patterns or their prevalence of use in orthopaedic sports medicine patients.

Purpose:

To report the prevalence and perceived self-efficacy of CBD products in patients evaluated in an orthopaedic sports medicine clinic.

Study Design:

Descriptive epidemiology study. Level of evidence, 2.

Methods:

The study population consisted of new patients who visited an orthopaedic surgery sports medicine clinic at a large academic center for consultation with a surgeon between August 2020 and March 2021. All patients were asked to complete a survey that assessed perceived pain and effectiveness of CBD products and other nonsurgical treatment modalities using the Single Assessment Numeric Evaluation score (range, 0-100) and the Numeric Pain Rating Scale (NRS). Descriptive factors were collected via chart review. Descriptive statistics were used to characterize the data.

Results:

Overall, 823 patients completed the survey (45.4% female; mean age, 51 years [range, 18-87 years]; mean body mass index, 28.9 [range, 17.2-58.4]). Body areas involved included 285 shoulders, 44 elbows, 76 hips, 276 knees, 58 ankles, and 77 other. Of these patients, 19% (152/823) endorsed the use of CBD products before their initial evaluation. The mean NRS for pain was significantly different between non-CBD users and CBD users (5.6 vs 6.1; P = .029). CBD users were significantly more likely to have tried other nonoperative modalities compared with nonusers, including nonsteroidal anti-inflammatory drugs (79.6% vs 69.8%; P = .032), bracing (44.7% vs 34.6%; P = .024), steroid injections (38.8% vs 21.6%; P < .001), and physical therapy (54% vs 36.1%; P < .001). In addition, 30.9% of CBD utilizers reported marijuana use compared with 2.8% of non-CBD users ( P < .001) for management of their pain.

Conclusion:

In the current study, 19% of patients had used CBD products to manage joint-related issues. Sports medicine providers should be aware of this high incidence of usage and the potential interactions CBD products may have with other treatment modalities. Further studies are needed to assess the effectiveness of CBD as a therapeutic agent and the specific interactions it has with other drugs and other forms of treatment.