Ultrasound-guided cervical facet joint injections.

BACKGROUND CONTEXT: Cervical facet joints are a common cause of chronic neck pain. Radiofrequency neurotomy is a validated treatment technique for cervical facet joint pain, but the role of intra-articular injections is less clear. Ultrasound guidance can be used to inject the cervical facet joints. Given that the accuracy of any injection technique is likely to affect treatment outcomes, it would be useful to know the accuracy of ultrasound-guided cervical facet joint injections. PURPOSE: The primary purpose of this study was to determine the accuracy of ultrasound-guided cervical facet joint injections using a lateral technique. The secondary purpose was to describe the technique. STUDY DESIGN/SETTING: Cohort study of ultrasound-guided cervical facet joint injections performed by an experienced spine and ultrasound interventionist, as assessed by contrast dye arthrography at a community interventional spine practice. PATIENT SAMPLE: Sixty joints in 36 patients with facet mediated pain. OUTCOME MEASURES: Accuracy of ultrasound-guided injections as determined by the percent of fluoroscopic contrast dye patterns interpreted to be intra-articular by the operator and an independent imaging specialist. Confidence intervals were determined using binomial "exact" and normal approximation to the binomial calculations. METHODS: Ultrasound using a long-axis or in-plane approach was used to guide a needle into a facet joint, followed by injection of contrast dye and a lateral fluoroscopic image. The dye pattern was interpreted by the operator. Depending on the pattern, local anesthetic and corticosteroid were injected. The patient was asked whether their neck pain had resolved. If not resolved, another joint was selected and the process was repeated. At the end of the study, all of the contrast patterns were interpreted independently by the imaging specialist. Funding was through a 501(c)(3) foundation without any commercial or sponsorship interests. RESULTS: The accuracy of ultrasound-guided cervical facet joint injections using the lateral technique ranged from 92% to 98% depending on the criteria used to confirm an intra-articular contrast pattern (95% CI: 0.82-0.97 to 0.91-1.0, and 0.85-0.99 to 0.95-1.00). The distribution of injections was C2-3 (22%), C3-4 (40%), C4-5 (33%) and C5-6 (5%). CONCLUSIONS: Cervical facet joint injections can be performed with a high degree of accuracy using a lateral ultrasound-guided technique. As with fluoroscopy-guided cervical facet joint injections, the technique requires a careful approach and a high degree of skill.

Ultrasonic aspiration for vaccination-related shoulder dysfunction.

BACKGROUND: Chronic shoulder pain occurs rarely after a vaccination and is hypothesized to arise from the effects of unintentional vaccine injection into the subacromial bursa, rotator cuff, capsule or underlying bone. The avascular nature of the rotator cuff, as well as unknown genetic and environmental factors, may predispose to the persistence of pain and disability, referred to as vaccination-related shoulder dysfunction and shoulder injury related to vaccine administration (SIRVA). METHODS: Ultrasonography, sonopalpation and ultrasound-guided anesthetic injections were used to locate the anatomical source of chronic (mean 20, range 8-42 months) shoulder pain after a vaccination in a consecutive series of 5 patients. Subsequently ultrasound-guided ultrasonic aspiration and debridement was performed using a 2.1 mm outer cannula with an inner needle vibrating at 28 kHz. Outcomes were assessed using the Quick Disabilities of the Arm, Shoulder and Hand (QDASH) scale at 2, 4, 12, 24 weeks and 1 year. RESULTS: The distal infraspinatus and teres minor tendons, their insertions and or the adjacent bone were the source of pain in all 5 patients. The mean QDASH score improved from 65 points to 11 points at 2 weeks (P = 0.001), and to 1 point at 4 weeks after the procedures (P = 0.003). Improvements in pain and function remained stable at 1 year in 3 patients, for at least 24 weeks in 1 patient who died of unrelated causes, and 1 year in 1 patient for posterior shoulder pain who after a pain free interval developed anterior shoulder pain related to his previously asymptomatic osteoarthritis (P = 0.013). CONCLUSION: The distal infraspinatus and teres minor tendons, their insertions and adjacent bone are a common source of chronic shoulder pain after a vaccination. Ultrasound-guided ultrasonic aspiration and debridement is a potentially effective treatment for resolving pain and restoring function.

Effect of local anesthetics on platelet physiology and function.

Local anesthetics are often used at the site of injury or mixed with platelet-rich plasma to reduce pain when treating orthopedic and sports-related injuries. Local anesthetics have been shown to have deleterious effects on stromal cells, but their impact on platelets has not been investigated. In this study, we aimed to assess the effects of lidocaine, bupivacaine, and ropivacaine on platelet health. Based on the deleterious effects of local anesthetics on nucleated cells, we hypothesized that these compounds would affect platelet viability, intracellular physiology, and function. Platelet preparations were derived from randomly selected donors and exposed to lidocaine 1%, bupivacaine 0.75%, ropivacaine 0.5%, and saline at 1:1 and 1:3 ratios. Platelet morphology, viability, intracellular calcium, production of radical oxygen species (ROS), apoptosis, and adhesion were assessed via fluorescent microscopy and flow cytometry. Bupivacaine resulted in increased ROS production, calcium dysregulation, apoptosis, and reduced platelet adhesion. By contrast, ropivacaine and lidocaine were similar to saline in most assays, except for a low degree of mitochondrial stress as evidenced by increased ROS production. Ultimately, bupivacaine 0.75% was harmful to platelets as evidenced by reduced platelet viability, adhesion, and increased apoptosis, whereas lidocaine 1% and ropivacaine 0.5% were relatively safe at the 1:1 and 1:3 dilutions. Clinical significance: Lidocaine 1% and ropivacaine 0.5% can be used at up to a 1:1 ratio with platelet preparations to reduce the pain and discomfort of PRP procedures while maintaining platelet therapeutic potential.

Human mesenchymal stem cells respond differentially to platelet preparations and synthesize hyaluronic acid in nucleus pulposus extracellular matrix.

BACKGROUND CONTEXT: In recent years, autologous platelet-rich plasma (PRP) and bone marrow aspirate concentrate (BMAC) have been used as treatments for disc-related pain. A better understanding of the effects of leukocyte-rich (LR) versus leukocyte poor (LP-) PRP on bone marrow derived human mesenchymal stem/progenitor cells (hMSCs) is likely to improve future research studies, clinical practice and care for patients with chronic discogenic back pain. PURPOSE: The primary aim of this study is to determine the effects of LR-PRP and LP-PRP on the proliferation and migration of hMSCs in pig nucleus pulposus (NP) extracellular matrix (ECM). The secondary aim is to characterize hMSC-dependent expression of the matrix remodeling enzymes metalloproteinases MMP-2, MMP-3, MMP-9 and tissue inhibitor of metalloproteinases TIMP-2, and to determine whether transplanted hMSCs can synthesize hyaluronic acid (HA). STUDY DESIGN: Controlled laboratory study. METHODS: Bone marrow-derived culture expanded hMSCs were seeded onto pig NP and cultured with LR-PRP, LP-PRP or serum/platelet releasate (PR). The same conditions without hMSCs were used as controls. hMSC proliferation, migration and dispersion was assessed via fluorescent microscopy, while HA synthesis, MMP-2, MMP-3, MMP-9, and TIMP-2 protein levels were assessed via enzyme linked immunosorbent assay. All funding was provided by a 501c(3) research foundation and does not have any commercial or sponsorship interests. RESULTS: LP-PRP and PR cultures resulted in higher hMSC proliferation, migration, dispersion, and MMP-2 expression. LP-PRP cultures resulted in the highest HA production. LR-PRP cultures resulted in lower hMSC proliferation, negligible migration and dispersion, increased MMP-9 expression and lower HA production. CONCLUSIONS: Human bone marrow-derived hMSCs seeded onto pig NP ECM are capable of synthesizing HA, indicating a transition towards a NP cell phenotype. This process was most enhanced by LP-PRP and marked by increased hMSC proliferation, MMP-2 production, HA synthesis and reduced MMP-9 levels. CLINICAL SIGNIFICANCE: LP-PRP and PR, with or without hMSCs, may provide better outcomes than LR-PRP in lab investigations and clinical trials for discogenic pain. Bone marrow-derived hMSCs may hold promise as a treatment for disc degeneration.