Despite its limitations, the ultrasound can be a useful tool to position the needle in the caudal space. It allows prompt identification of the sacral anatomy and real-time visualization of the injection. Considering it is portable, non-invasive, and free of radiation exposure, it is an attractive technique in the operating room especially in difficult cases. However, since its use in neuroaxis anesthesia is very primitive, more studies are necessary to make it a routine technique in anesthetic practice.
Objective
Upper limb complex regional pain syndrome is an important cause of chronic pain, and its treatment is challenging. In this pilot case series, we preliminarily evaluated the feasibility, effectiveness, and safety of a new technique for brachial plexus neuromodulation in the treatment of this disease in patients refractory to conservative treatment.
Methods
Between 2017 and 2018, 14 patients considered to be refractory to optimized conservative treatment were recruited to this study. In the first stage, patients were trialed for seven days with a new technique of implant of the brachial plexus. Patients with ≥50% pain relief in visual analog scale (VAS) score received a definitive implantation in the second stage. Follow-ups were conducted at pre-implant and 12 months using the Neuropathic Pain Scale, SF-32, and the visual analogic scale for pain.
Results
After the initial trial, 10 patients had a pain reduction of ≥50% and received a permanent implant. At 12-month follow-up, VAS, Neuropathic Pain Scale, SF-12 physical and mental scores improved by 57.4% +/- 10% (P = 0.005), 60.2% +/- 12.9% (P = 0.006), and 21.9% +/- 5.9% (P = 0.015), respectively.
Conclusions
Our data suggest that this new technique of brachial plexus stimulation may have long-term utility in the treatment of painful upper limb complex regional pain syndrome. New more detailed comprehensive studies should be carried out to confirm our findings in a larger population and to further refine the clinical implementation of this technique.
Background
Radiofrequency ablation of the genicular nerve is performed for knee osteoarthritis (KOA) when conservative treatment is not effective. Chemical ablation may be an alternative, but its effectiveness and safety have not been examined. The objective of this prospective open‐label cohort study is to evaluate the effectiveness and safety of ultrasound‐guided chemical neurolysis for genicular nerves with phenol to treat patients with chronic pain from KOA.
Methods
Forty‐three patients with KOA with pain intensity score (Numeric Rating Scale, NRS) ≥ 4, and duration of pain of more than 6 months were considered for enrollment. Ultrasound‐guided diagnostic blocks of genicular nerves (superomedial, inferomedial, and superolateral) with 1.5 mL of 0.25% bupivacaine at each site were performed. Those who reported more than 50% reduction in NRS went on to undergo chemical neurolysis, using 1.5 mL 7% glycerated phenol in each genicular nerve. NRS and Western Ontario and McMaster Universities Arthritis Index (WOMAC) scores were assessed before intervention and at 2 weeks and 1, 2, 3, and 6 months following the intervention.
Results
NRS and WOMAC scores improved at all time points. Mean pain intensity improved from 7.2 (95% confidence interval [CI]: 6.8 to 7.7) at baseline to 4.2 (95%CI: 3.5 to 5.0) at 6‐month follow‐up (P < 0.001). Composite WOMAC score improved from 48.7 (95%CI: 43.3 to 54.2) at baseline to 20.7 (95%CI: 16.6 to 24.7) at 6‐month follow‐up (P < 0.001). Adverse events did not persist beyond 1 month and included local pain, hypoesthesia, swelling, and bruise.
Conclusion
Chemical neurolysis of genicular nerves with phenol provided efficacious analgesia and functional improvement for at least 6 months in most patients with a low incidence of adverse effects.
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