To investigate the comparative treatment effects of ultrasound-guided pulsed radiofrequency treatment (UG-PRF) in the gastrocnemius interfascial space and ultrasound-guided interfascial injection (UG-INJ) on myofascial pain syndrome.
Forty consecutive patients with myofascial pain syndrome of the gastrocnemius were enrolled and were allocated to one of the two groups. Twenty patients were treated by UG-PRF delivered to the gastrocnemius interfascial space (UG-PRF group) and the other 20 patients were treated by interfascial injection (UG-INJ group). The primary outcome measure was the numeric rating score (NRS) for pain on pressing the tender point in the gastrocnemius, and the secondary outcome measure was health-related quality of life as determined by the Short Form-36 questionnaire (SF-36). NRSs were obtained at the first visit, immediately after treatment, and at 2 and 4 weeks post-treatment, and physical component summary scores (PCS) and mental component summary scores (MCS) of the SF-36 questionnaire were measured at the first visit and at 4 weeks post-treatment.
Immediately after treatments, mean NRS in the UG-PRF group was significantly higher than that in the UG-INJ group (p<0.0001). However, at 2 and 4 weeks post-treatment, the mean NRS was significantly lower in the UG-PRF group (both p<0.0001). Similarly, at 4 weeks post-treatment, mean PCS and MCS were significantly higher in the UG-PRF group (p<0.0001 and p=0.002, respectively).
Based on these results, the authors conclude that ultrasound-guided gastrocnemius interfascial PRF provides an attractive treatment for myofascial pain syndrome of the gastrocnemius.
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To investigate the effect of pulsed radiofrequency (PRF) applied proximal to the injured peripheral nerve on the expression of tumor necrosis factor-α (TNF-α) in a neuropathic pain rat model.
Nineteen male Sprague-Dawley rats were used in the study. All rats underwent chronic constriction injury (CCI) procedure. After 7 days of CCI, withdrawal frequency of affected hind paw to mechanical stimuli and withdrawal latency of affected hind paw to heat stimulus were measured. They were randomly divided into two groups: group A, CCI group (n=9) and group B, CCI treated with PRF group (n=10). Rats of group B underwent PRF procedure on the sciatic nerve. Withdrawal frequency and withdrawal latency were measured at 12 hours, and 7 days after PRF. Immunohistochemistry and Western blot analysis were performed using a TNF-α antibody.
Before PRF, withdrawal frequency and withdrawal latency were not different in both groups. After PRF, withdrawal frequency decreased and withdrawal latency prolonged over time in group B. There was significant interaction between time and group for each withdrawal frequency and withdrawal latency. Group B showed decreased TNF-α immunoreactivity of the spinal cord and sciatic nerve at 7 days.
PRF applied proximal to the peripheral nerve injury is potentially helpful for the reduction of neuropathic pain by neuromodulation of inflammatory markers.
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To investigate the efficacy and safety of percutaneous intradiscal monopolar pulsed radiofrequency (PRF) in patients with chronic disabling discogenic back pain.
Twenty-six subjects (7 males; mean age 43.2 years) with chronic back pain refractory to active rehabilitative management were recruited. All subjects underwent MRI for evaluation of Modic changes, and monopolar PRF (20 min at 60 V) at the center of target lumbar intervertebral disc confirmed by pressure-controlled provocative discography. Clinical outcomes were measured by the visual analogue scale (VAS), Oswestry disability index (ODI), and sitting tolerance time (ST) for 12 months after treatment. Successful clinical outcome was described as a minimum of 2 point reduction in VAS compared with the baseline at each follow-up period.
The mean VAS for low back pain reduced significantly from 6.4±1.1 at pre-treatment to 4.4±1.9 at 12 months (p<0.05). The mean ODI score was 47.3±15.4 points at pre-treatment and 36.7±19.5 at 12 months (p<0.001). The ST was 27.8±20.4 minutes at pre-treatment and 71.5±42.2 at 12 months (p<0.001). However, successful clinical outcome was achieved at 58%, 50%, and 42%, measured at 3, 6, and 12 months post-treatment. There were no significant relationship between the clinical outcome and Modic changes; no adverse events were recorded.
The results demonstrated that the application of intradiscal monopolar PRF might be relatively effective but limited; successful intervention for chronic refractory discogenic back pain is needed. To achieve the optimal outcome through intradiscal PRF, we suggested further studies about stimulation duration, mode, and intensity of PRF.
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To evaluate the short-term effectiveness of pulsed radiofrequency on the dorsal root ganglion (DRG) in patients with chronic refractory cervical radicular pain.
Fifteen patients (13 males, 2 females; mean age, 55.9 years) with chronic radicular pain due to cervical disc herniation or foraminal stenosis refractory to active rehabilitative management, including transforaminal cervical epidural steroid injection and exercise, were selected. All patients received pulsed radiofrequency on the symptomatic cervical dorsal root ganglion and were carefully evaluated for neurologic deficits and side effects. The clinical outcomes were measured using a visual analogue scale (VAS) and a neck disability index (NDI) before treatment, one and three months after treatment. Successful pain relief was defined as a 50% or greater reduction in the VAS score as compared with the pre-treatment score. After three months, we categorized the patients' satisfaction.
The average VAS for radicular pain was reduced significantly from 5.3 at pretreatment to 2.5 at 3 months post-treatment (p<0.05). Eleven of 15 patients (77.3%) after cervical pulsed RF stimulation reported pain relief of 50% or more at the 3 month follow-up. The average NDI was significantly reduced from 44.0% at pretreatment to 35.8% 3 months post-treatment (p<0.05). At 3 months post-treatment, eleven of fifteen patients (73.3%) were satisfied with their status. No adverse effects were observed.
The results demonstrate that the application of pulsed radiofrequency on DRG might be an effective short-term intervention for chronic refractory cervical radicular pain. Further studies, including a randomized controlled trial with long-term follow-up, are now needed.
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