We present a case of a lumbar perineural cyst treated with nerve root pulsed radiofrequency and steroid therapy to address severe lower limb pain. The patient, a 43-year-old man, sought care at our orthopedic department for persistent left thigh pain, rated 7 on the numerical rating scale (NRS) for the past month. He exhibited left L3 radicular pain, and lumbar MRI confirmed a 10 mm perineural cyst at the left L3 nerve root. Referred for pain management, the patient received pulsed radiofrequency therapy combined with steroid administration, resulting in pain reduction to NRS 2. Perineural cysts, extensions of the dura mater along the nerve root, are often discovered incidentally through advanced imaging techniques. While most remain asymptomatic, they can cause pain from nerve root compression or bone erosion. Various interventions, including surgical options and percutaneous cyst puncture, have proven effective, underscoring the potential of pulsed radiofrequency therapy for radicular pain related to lumbar perineural cysts.

Case: A 17-year-old female basketball player diagnosed with lumbar spondylolysis at another hospital was referred to our clinic. Her back pain worsened after a traumatic injury during a game. She developed persistent left lumbar pain, exacerbated by trunk rotation, difficulty with load-bearing to the left, and claudication. A CT scan of the lumbar spine revealed separation of the fifth lumbar vertebra (right fusion, left pseudarthrosis). Progress: Exercise therapy was ineffective and pain relief with intervertebral joint block was limited. Direct administration of local anesthetics to the separation area provided a short-term relief. Considering lumbar spondylolysis as the main cause of the patient's low back pain, we performed radiofrequency thermocoagulation (60℃ for 6 minutes) to achieve long-term effects. Improvement in lower back pain and alleviation of limping have been observed since the implementation, and there was no deterioration in symptoms even after 6 months. Conclusion: Pseudarthrosis radiofrequency thermocoagulation may improve low back pain in patients with lumbar spondylolysis.

Fentanyl patch (FP) has been available for more than 10 years for the management of intractable chronic pain. Indications for chronic pain is still problematic in terms of duration and dosage. In this study, we planned to switch to oxycodone while measuring serum concentrations of fentanyl in patients who had been using long-term, very high-dose FP for intractable chronic pain due to familial Mediterranean fever, an incurable disease, and musculoskeletal disease. The patient was switched to oxycodone while serum fentanyl concentrations were measured. The patient was initially managed as an inpatient and was able to reduce the opioid dose to about 1/3 of the original dose over 21 weeks, while improving activities of daily living and quality of life.