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Object Herniated discs can induce sciatica by mechanical compression and/or chemical irritation caused by proinflammatory cytokines. Using immunohistochemistry methods in the dorsal horn of a rat model of lumbar disc herniation, the authors investigated the effects of pulsed radiofrequency (PRF) current administration to the dorsal root ganglion (DRG) on pain-related behavior and activation of microglia, astrocytes, and mitogen-activated protein kinase. Methods A total of 33 Sprague-Dawley rats were randomly assigned to either a sham-operated group (n = 10) or a nucleus pulposus (NP)–exposed group (n = 23). Rats in the NP-exposed group were further subdivided into NP exposed with sham stimulation (NP+sham stimulation, n = 10), NP exposed with PRF (NP+PRF, n = 10), or euthanasia 10 days after NP exposure (n = 3). The DRGs in the NP+PRF rats were exposed to PRF waves (2 Hz) for 120 seconds at 45 V on postoperative Day 10. Rats were tested for mechanical allodynia 10 days after surgery and at 8 hours, 1 day, 3 days, 10 days, 20 days, and 40 days after PRF administration. Immunohistochemical staining of astrocytes (glial fibrillary acidic protein), microglia (OX-42), and phosphorylated extracellular signal–regulated kinases (pERKs) in the spinal dorsal horn was performed at 41 days after PRF administration. Results Starting at 8 hours after PRF administration, mechanical withdrawal thresholds dramatically increased; this response persisted for 40 days (p < 0.05). After PRF administration, immunohistochemical expressions of OX-42 and pERK in the spinal dorsal horn were quantitatively reduced (p < 0.05). Conclusions Pulsed radiofrequency administration to the DRG reduced mechanical allodynia and downregulated microglia activity and pERK expression in the spinal dorsal horn of a rat model of lumbar disc herniation.

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Background:This study aimed to demonstrate the effect of intra-articular (IA) lumbar facet joint (LFJ) pulsed radiofrequency (PRF) for the management of LFJ pain, and to compare the effect of IA LFJ PRF to IA corticosteroid injection (ICI). Pathology in the LFJ is a common source of lower back pain (LBP). It is responsible for chronic LBP in approximately 15% to 45% of patients. It has been reported that PRF stimulation can effectively reduce refractory joint pain.Methods:Sixty patients with LFJ pain were recruited and randomly assigned to 1 of 2 groups: the IA PRF group and the ICI group. There were 30 patients in each group. At pretreatment, 2 weeks, 1, 3, and 6 months after treatment, we assessed the severity of LBP using a numeric rating scale (NRS).Results:Compared with the pretreatment NRS scores, patients in both groups showed a significant decrease in NRS scores at 2 weeks, and 1, 3, and 6 months after each treatment. Between groups, changes in the NRS scores were significantly different over time. At 2 weeks and 1 month after each procedure, the NRS score after ICI was significantly lower than that after the PRF stimulation. However, at 3 and 6 months after the procedures, the decrements of NRS scores were not significantly different between the 2 groups. Six months after treatment, about half of patients in both groups reported successful pain relief (pain relief of ≥50%).Conclusion:In the current study, both IA PRF stimulation and ICI into the LFJ significantly relieved LFJ pain. Their effects persisted for at least 6 months after the procedure. Thus, IA PRF is a useful therapeutic option for the management of LFJ pain.

Background:Chronic lumbosacral radicular pain is a challenging medical problem with respect to therapeutic management. Many patients with lumbosacral radicular pain complain of persistent leg pain after transforaminal epidural steroid injection. Nowadays, pulsed radiofrequency (PRF) stimulation on the dorsal root ganglion (DRG) is widely used for controlling lumbosacral radicular pain.Methods:We evaluated the effect of bipolar PRF on the DRG for the management of lumbosacral radicular pain. In addition, we compared the effect of bipolar PRF to monopolar PRF. Fifty patients with chronic lumbosacral radicular pain were included in the study and randomly assigned to 1 of 2 groups, the bipolar or monopolar PRF group (n = 25 per group). Pain intensity was evaluated using a numeric rating scale (NRS) at pretreatment, and 1, 2, and 3 months after treatment.Results:When compared to the pretreatment NRS scores, patients in both groups showed a significant decrease in NRS scores at 1, 2, and 3 months after treatment. Reductions in the NRS scores over time were significantly larger in the bipolar PRF group. Three months after treatment, 19 patients (76.0%) in the bipolar PRF group and 12 patients (48.0%) in the monopolar PRF group reported successful pain relief (pain relief of ≥50%).Conclusion:The use of bipolar PRF on the DRG can be an effective and safe interventional technique for chronic refractory lumbosacral radiculopathy, particularly in patients whose pain are refractory to epidural steroid injection or monopolar PRF stimulation.

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ObjectiveTo investigate changes in lumbar multifidus (LM) and deep lumbar stabilizing abdominal muscles (transverse abdominis [TrA] and obliquus internus [OI]) during transcutaneous neuromuscular electrical stimulation (NMES) of lumbar paraspinal L4-L5 regions using real-time ultrasound imaging (RUSI).MethodsLumbar paraspinal regions of 20 healthy physically active male volunteers were stimulated at 20, 50, and 80 Hz. Ultrasound images of the LM, TrA, OI, and obliquus externus (OE) were captured during stimulation at each frequency.ResultsThe thicknesses of superficial LM and deep LM as measured by RUSI were greater during NMES than at rest for all three frequencies (p<0.05). The thicknesses in TrA, OI, and OE were also significantly greater during NMES of lumbar paraspinal regions than at rest (p<0.05).ConclusionThe studied transcutaneous NMES of the lumbar paraspinal region significantly activated deep spinal stabilizing muscle (LM) and the abdominal lumbar stabilizing muscles TrA and OI as evidenced by RUSI. The findings of this study suggested that transcutaneous NMES might be useful for improving spinal stability and strength in patients having difficulty initiating contraction of these muscles.

Myofascial pain syndrome (MPS) of the trapezius muscle (TM) is a frequently occurring musculoskeletal disorder. However, the treatment of MPS of the TM remains a challenge. We investigated the effects of ultrasound (US)-guided pulsed radiofrequency (PRF) stimulation on the interfascial area of the TM. In addition, we compared its effect with that of interfascial block (IFB) with 10 mL of 0.6% lidocaine on the interfascial area of the TM. Thirty-six patients with MPS of the TM were included and randomly assigned into 2 groups. Eighteen patients underwent PRF stimulation on the interfascial area of the TM (PRF group) and 18 patients underwent IFB with lidocaine on the same area (IFB group). Pain intensity was evaluated using a numerical rating scale (NRS) at pretreatment, 2, 4, and 8 weeks after treatment. At pretreatment and 8 weeks after treatment, quality of life was assessed using the Short Form-36 Health Survey (SF-36), which includes the physical component score (PCS) and the mental component score (MCS). One patient in the PRF group was lost to follow-up. Patients in both groups showed a significant decrease in NRS scores at 2, 4, and 8 weeks after treatments and a significant increase in PCS and MCS of the SF-36 at 8 weeks after treatments. Two weeks after each treatment, the decrements of NRS scores were not significantly different between the 2 groups. However, 4 and 8 weeks after the procedures, we found that the NRS score was significantly lower in the PRF group than in the IFB group. At 8 weeks after the treatments, PCS and MCS of the SF-36 in the PRF group were significantly higher than those in the IFB group. For the management of MPS of the TM, US-guided interfascial PRF had a better long-term effect on reducing the pain and the quality of life compared to US-guided IFB. Therefore, we think US-guided PRF stimulation on the interfascial area of the TM can be a beneficial alternative to manage the pain following MPS of the TM.