A Prospective Randomized Trial of Prognostic Genicular Nerve Blocks to Determine the Predictive Value for the Outcome of Cooled Radiofrequency Ablation for Chronic Knee Pain Due to Osteoarthritis.

Background and Objectives: Genicular nerve radiofrequency ablation is an effective treatment for patients with chronic pain due to knee osteoarthritis; however, little is known about factors that predict procedure success. The current study evaluated the utility of genicular nerve blocks to predict the outcome of genicular nerve cooled radiofrequency ablation (cRFA) in patients with osteoarthritis. Methods: This randomized comparative trial included patients with chronic knee pain due to osteoarthritis. Participants were randomized to receive a genicular nerve block or no block prior to cRFA. Patients receiving a prognostic block that demonstrated ≥50% pain relief for six hours received cRFA. The primary outcome was the proportion of participants with ≥50% reduction in knee pain at six months. Results: Twenty-nine participants (36 knees) had cRFA following a prognostic block, and 25 patients (35 knees) had cRFA without a block. Seventeen participants (58.6%) in the prognostic block group and 16 (64.0%) in the no block group had ≥50% pain relief at six months (P = 0.34). A 15-point decrease in the Western Ontario and McMaster Universities Osteoarthritis Index at six months was present in 17 of 29 (55.2%) in the prognostic block group and 15 of 25 (60%) in the no block group (P = 0.36). Conclusions: This study demonstrated clinically meaningful improvements in pain and physical function up to six months following cRFA. A prognostic genicular nerve block using a local anesthetic volume of 1 mL at each injection site and a threshold of ≥ 50% pain relief for subsequent cRFA eligibility did not improve the rate of treatment success.

A Prospective Randomized Comparative Trial of Targeted Steroid Injection Via Epidural Catheter Versus Standard C7-T1 Interlaminar Approach for the Treatment of Unilateral Cervical Radicular Pain.

BACKGROUND AND OBJECTIVES: No study has compared cervical interlaminar epidural steroid injection (CIESI) with epidural catheter advancement to the side and level of pathology versus standard C7-T1 CIESI. This study investigated whether cervical radicular pain is more effectively treated by CIESI with a targeted epidural catheter versus a standard C7-T1 approach. METHODS: Prospective, randomized, single-blinded trial. PRIMARY OUTCOME: Numerical Rating Scale (NRS) pain at 1 month. SECONDARY OUTCOMES: Oswestry Neck Disability Index (ONDI), Pain Disability Index (PDI), McGill Pain Questionnaire (MPQ), Patient Global Impression of Change (PGIC), daily morphine equivalents (DME), and Medication Quantification Scale (MQS) III scores. RESULTS: Seventy-six participants with a median age of 48 years (IQR, 40-56 years), 59% female, with C4 (n = 2), C5 (n = 27), or C6 (n = 47) radicular pain were enrolled. At 1 month in the catheter and no catheter groups, respectively: 26 (72%, 95% confidence interval [CI], 57%-87%) and 23 (60%; 95% CI, 45%-75%) participants reported 50% or greater NRS reduction; 24 (67%; 95% CI, 52%-84%) and 23 (58%; 95% CI, 42%-73%) participants reported 30% or greater ONDI reduction. There were no group differences in median NRS, ONDI, PDI, MPQ, PGIC, DME, or MQSIII scores (P > 0.05). Intergroup differences were not observed at any follow-up interval. CONCLUSIONS: This trial showed no significant difference in clinical outcomes with CIESI using a targeted epidural catheter compared to a standard C7-T1 approach for the treatment of unilateral cervical radicular pain at the C5 or C6 level. Both techniques were associated with clinically meaningful improvement across outcome domains of pain, function, disability, and medication use. These effects persisted to 6-month follow-up.The study was registered at Clinical Trials.gov (NCT02095197).

Characterization and in vitro cytotoxicity testing of ethanolamine-derived cadmium chelating agents.

We have synthesized and characterized the new cadmium chelating agent potassium bis(2-hydroxyethyl)aminoethyldithiocarbonate hemihydrate, K[bhexan] x 0.5H2O (2), that is structurally related to the known effective in vivo cadmium chelating agent potassium bis(2-hydroxyethyl)dithiocarbamate, K[bhedtc] (1). The corresponding cadmium complex of 2 differs from di(bis(2-hydroxyethyl)dithiocarbamato)cadmium(II), Cd(bhedtc)2 (3), in that the insoluble compound exhibits an elemental composition consistent with a cadmium:ligand ratio of 2:1. The cytotoxicity of the 1-3 was investigated using the human osteoblast-like cell line, Saos-2. Compounds 1 or 2 did not affect cell adherence or cell viability in the 100-500 microM concentration range studied, whereas 3 resulted in a concentration-dependent increase in loss of cell adherence and decrease in cell viability. Overall, the results of the loss of cell adherence, trypan blue exclusion and MTT assays showed that administration of 3 (cadmium complex of 1) resulted in cytotoxicity lower than that of cadmium chloride, but higher than that of the chelator 1 alone. The effect of simultaneous addition of cadmium chloride and 1 or 2 on cell viability was also assessed using the MTT assay. For the 100 microM cadmium chloride experiments, cell viability comparable to control cells was achieved for both 1 and 2 in the 100-500 microM concentration range studied. Cell viability comparable to control cells was achieved for 1 but not 2 in the 100-500 microM concentration range studied for the 200 microM cadmium chloride experiments. Thus 1 appears more effective than 2 in the ability to mediate the cytotoxic effects of cadmium in vitro upon concomitant administration.