• The Korean Journal of Pain
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• v.35 no.2
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• pp.183-190
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• 2022

Background: To compare ultrasound-guided pulsed radiofrequency (PRF) of the genicular nerve with the genicular nerve block using local anesthetic and steroid for management of osteoarthritis (OA) knee pain. Methods: Thirty patients with OA knee were randomly allocated to receive either ultrasound-guided PRF of the genicular nerve (PRF group) or nerve block with bupivacaine and methylprednisolone acetate (local anesthetic steroid [LAS] group). Verbal numeric rating scale (VNRS) and Western Ontario McMaster Universities Osteoarthritis Index (WOMAC) scores were measured at pre-procedure and 1-, 4-, and 12-weeks post-procedure. Results: VNRS scores decreased significantly (P < 0.001) in both the groups at 12 weeks and other follow up times compared to baseline. Seventy-three percent of patients in the PRF group and 66% in the LAS group achieved effective pain relief (≥ 50% pain reduction) at 12 weeks (P > 0.999). There was also a statistically significant (P < 0.001) improvement in WOMAC scores in both groups at all follow up times. However, there was no intergroup difference in VNRS (P = 0.893) and WOMAC scores (P = 0.983). No complications were reported. Conclusions: Both ultrasound-guided PRF of the genicular nerve and blocks of genicular nerve with local anesthetic and a steroid provided comparable pain relief without any complications. However, PRF of the genicular nerve is a procedure that takes much more time and equipment than the genicular nerve block.

• Clinics in Shoulder and Elbow
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• v.24 no.1
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• pp.36-41
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• 2021

Chronic shoulder pain not relieved by either conservative or surgical management is referred to as chronic refractory shoulder pain. This is a retrospective case series where chronic refractory shoulder pain patients were treated either with peripheral nerve stimulation (PNS) or with pulsed radiofrequency (p-RF) therapy to the suprascapular nerve. Both patients receiving PNS reported 100% pain relief for the first month. At the 3- and 6-month follow-ups, one patient continued to experience 100% relief while the other reported 90% relief. One patient undergoing p-RF experienced about 90% pain relief at both 1- and 3-month intervals and 0% relief at the 6-month interval. The other patient with p-RF experienced 33% relief at 1-month and 0% relief thereafter. No patient reported any complications. The results of previous randomized controlled trials evaluating the efficacy of p-RF administered to the suprascapular nerve were mixed, and there is a lack of published studies on PNS effects. Neuromodulation of the suprascapular nerve can be effective for chronic refractory shoulder pain patients. Larger scale randomized controlled trials comparing PNS and p-RF are needed to better understand their respective therapeutic capacity.

• Journal of Korean Neurosurgical Society
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• v.54 no.6
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• pp.507-510
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• 2013

Objective : The aim of this study was to evaluate effect of pulsed radiofrequency (PRF) neuromodulation of suprascpaular nerve (SSN) in patients with chronic shoulder pain due to adhesive capsulitis and/or rotator cuff tear. Methods : The study included 11 patients suffering from chronic shoulder pain for at least 6 months who were diagnosed with adhesive capsulitis (n=4), rotator cuff tear (n=5), or adhesive capsulitis+rotator cuff tear (n=2) using shoulder magnetic resonance imaging or extremity ultrasonography. After a favorable response to a diagnostic suprascapular nerve block twice a week (pain improvement >50%), PRF neuromodulation was performed. Shoulder pain and quality of life were assessed using a Visual Analogue Scale (VAS) and the Oxford Shoulder Score (OSS) before the diagnostic block and every month after PRF neuromodulation over a 9-month period. Results : The mean VAS score of 11 patients before PRF was $6.4{\pm}1.49$, and the scores at 6-month and 9 month follow-up were $1.0{\pm}0.73$ and $1.5{\pm}1.23$, respectively. A significant pain reduction (p<0.001) was observed. The mean OSS score of 11 patients before PRF was $22.7{\pm}8.1$, and the scores at 6-month and 9 month follow-up were $41.5{\pm}6.65$ and $41.0{\pm}6.67$, respectively. A significant OSS improvement (p<0.001) was observed. Conclusion : PRF neuromodulation of the suprascapular nerve is an effective treatment for chronic shoulder pain, and the effect was sustained over a relatively long period in patients with medically intractable shoulder pain.

• The Korean Journal of Pain
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• v.29 no.1
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• pp.3-11
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• 2016

A nerve block is an effective tool for diagnostic and therapeutic methods. If a diagnostic nerve block is successful for pain relief and the subsequent therapeutic nerve block is effective for only a limited duration, the next step that should be considered is a nerve ablation or modulation. The nerve ablation causes iatrogenic neural degeneration aiming only for sensory or sympathetic denervation without motor deficits. Nerve ablation produces the interruption of axonal continuity, degeneration of nerve fibers distal to the lesion (Wallerian degeneration), and the eventual death of axotomized neurons. The nerve ablation methods currently available for resection/removal of innervation are performed by either chemical or thermal ablation. Meanwhile, the nerve modulation method for interruption of innervation is performed using an electromagnetic field of pulsed radiofrequency. According to Sunderland's classification, it is first and foremost suggested that current neural ablations produce third degree peripheral nerve injury (PNI) to the myelin, axon, and endoneurium without any disruption of the fascicular arrangement, perineurium, and epineurium. The merit of Sunderland's third degree PNI is to produce a reversible injury. However, its shortcoming is the recurrence of pain and the necessity of repeated ablative procedures. The molecular mechanisms related to axonal regeneration after injury include cross-talk between axons and glial cells, neurotrophic factors, extracellular matrix molecules, and their receptors. It is essential to establish a safe, long-standing denervation method without any complications in future practices based on the mechanisms of nerve degeneration as well as following regeneration.

• The Korean Journal of Pain
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• v.29 no.2
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• pp.123-128
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• 2016

Phantom limb pain is a phenomenon in which patients experience pain in a part of the body that no longer exists. In several treatment modalities, spinal cord stimulation (SCS) has been introduced for the management of intractable post-amputation pain. A 46-year-old male patient complained of severe ankle and foot pain, following above-the-knee amputation surgery on the right side amputation surgery three years earlier. Despite undergoing treatment with multiple modalities for pain management involving numerous oral and intravenous medications, nerve blocks, and pulsed radiofrequency (RF) treatment, the effect duration was temporary and the decreases in the patient's pain score were not acceptable. Even the use of SCS did not provide completely satisfactory pain management. However, the trial lead positioning in the cauda equina was able to stimulate the site of the severe pain, and the patient's pain score was dramatically decreased. We report a case of successful pain management with spinal cauda equina stimulation following the failure of SCS in the treatment of intractable phantom limb pain.

• The Korean Journal of Pain
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• v.24 no.3
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• pp.154-157
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• 2011

Background: Postherpetic neuralgia (PHN) is usually managed pharmacologically. It is not uncommon for patients with chronic kidney disease (CKD) to suffer from PHN. It is difficult to prescribe a sufficient dose of anticonvulsants for intractable pain because of the decreased glomerular filtration rate. If the neural blockade and pulsed radiofrequency ablation provide only short-term amelioration of pain, spinal cord stimulation (SCS) with a low level of evidence may be used only as a last resort. This study was done to evaluate the efficacy of spinal cord stimulation in the treatment of PHN in patients with CKD. Methods: PHN patients with CKD who needed hemo-dialysis who received insufficient relief of pain over a VAS of 8 regardless of the neuropathic medications were eligible for SCS trial. The follow-up period was at least 2 years after permanent implantation. Results: Eleven patients received percutaneous SCS test trial from Jan 2003 to Dec 2007. Four patients had successfully received a permanent SCS implant with their pain being tolerable at a VAS score of less than 3 along with small doses of neuropathic medications. Conclusions: SCS was helpful in managing tolerable pain levels in some PHN patients with CKD along with tolerable neuropathic medications for over 2 years.

• The Korean Journal of Pain
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• v.31 no.3
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• pp.155-173
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• 2018

Chronic postsurgical pain (CPSP) is an unwanted adverse event in any operation. It leads to functional limitations and psychological trauma for patients, and leaves the operative team with feelings of failure and humiliation. Therefore, it is crucial that preventive strategies for CPSP are considered in high-risk operations. Various techniques have been implemented to reduce the risk with variable success. Identifying the risk factors for each patient and applying a timely preventive strategy may help patients avoid the distress of chronic pain. The preventive strategies include modification of the surgical technique, good pain control throughout the perioperative period, and preoperative psychological intervention focusing on the psychosocial and cognitive risk factors. Appropriate management of CPSP patients is also necessary to reduce their suffering. CPSP usually has a neuropathic pain component; therefore, the current recommendations are based on data on chronic neuropathic pain. Hence, voltage-dependent calcium channel antagonists, antidepressants, topical lidocaine and topical capsaicin are the main pharmacological treatments. Paracetamol, NSAIDs and weak opioids can be used according to symptom severity, but strong opioids should be used with great caution and are not recommended. Other drugs that may be helpful are ketamine, clonidine, and intravenous lidocaine infusion. For patients with failed pharmacological treatment, consideration should be given to pain interventions; examples include transcutaneous electrical nerve stimulation, botulinum toxin injections, pulsed radiofrequency, nerve blocks, nerve ablation, neuromodulation and surgical management. Physical therapy, cognitive behavioral therapy and lifestyle modifications are also useful for relieving the pain and distress experienced by CPSP patients.