Characterisation of the effects of pulsed radio frequency treatment of the dorsal root ganglion on cerebrospinal fluid cellular and peptide constituents in patients with chronic radicular pain: A randomised, triple-blinded, controlled trial.

INTRODUCTION: Chronic radicular neuropathic pain is a major clinical problem with a life time prevalence of more than 50%. Pulsed radiofrequency (PRF) treatment is a recognised therapy. However, the pathophysiology of chronic neuropathic pain (CNP) and the mechanism of action of PRF remains ill-defined. Improving our knowledge of the mechanisms of CNP and PRF action will enhance our ability to treat patients with this common debilitating problem more effectively. This study aims to characterise the CSF cellular and peptide constituents in patients with CNP and the effect of pulsed radiofrequency (PRF) on these constituents and reported pain. MATERIALS AND METHODS: Prospective randomised tripled-blinded control trial of patients receiving PRF treatment versus sham for radicular pain. All patients received local anaesthetic to the appropriate dermatome to confirm diagnosis. Clinical assessment using standard clinical assessment tools and examination of CSF using flow cytometry and ELISA for cellular and peptide constituents was carried out before and 3 months after treatment. RESULTS: Ten patients were randomised to PRF (n = 5) or Sham (n = 5) treatment. PRF resulted in a significant reduction in pain score (NRS) at 3 months (6.8 to 2.6, p < .05). PRF reduced the TNF-α concentration and CD3+ count in CSF. CD4/CD8 ratio of patients with CNP was lower than historical controls (1.4 versus 3.0-4.2). The majority of CD3+ cells in the CNP patients were activated effector memory cells (80%) versus the surveillance central memory cells (85%) seen in healthy controls. CONCLUSIONS: PRF is superior to local anaesthetic administration for the management of radicular pain and is associated with CSF constituent modulation in vivo. Patients with CNP have lymphocyte characteristics which suggest immune activation.

Dorsal root ganglion pulsed radiofrequency treatment for chronic cervical radicular pain: a retrospective review of outcomes in fifty-nine cases.

Pulsed radiofrequency treatment adjacent to the cervical dorsal root ganglion is used to treat persistent cervical radicular pain that has not responded to conservative therapies. This technique has gained popularity in years for both cervical and lumbosacral radicular pain. The evidence to support its use is still evolving. METHODS: We performed a retrospective review of outcomes in 59 patients who underwent this therapy over a 3-year period in our institution. We evaluated a reduction in pain, duration of pain relief, reduction in use of analgesics and progression to surgery. RESULTS: Our results demonstrated 49 patients experienced some relief. Forty patients of the 59 experienced an improvement in pain of 50% or more. The mean duration of relief in this group was 37 weeks. Seven patients experienced complete resolution of their pain. In this group, the mean duration of relief was 39 weeks. Regarding the 53 patients who were taking medication for pain prior to the procedure, 37 patients reduced or discontinued their usage after the procedure. CONCLUSION: Despite the limitations of a retrospective study, we feel our study adds to the growing evidence base that pulsed radiofrequency treatment adjacent to the cervical dorsal root ganglion has a role in the treatment of chronic cervical radicular pain.

Human dorsal root ganglion pulsed radiofrequency treatment modulates cerebrospinal fluid lymphocytes and neuroinflammatory markers in chronic radicular pain.

Radicular pain is a common cause of disability. Traditionally treatment has been either epidural steroid injection providing short-term relief or surgery with associated complications. Pulsed radiofrequency (PRF) applied to the dorsal root ganglion (DRG) is a minimally invasive day-care treatment, which is gaining significant clinical acceptance in a selective group of patients with pure radicular pain. Greater insights into the immunomodulatory effects of this procedure may help to further optimise its application and find alternative treatment options. We have examined it's effect on lymphocyte frequencies and secreted inflammatory markers in the cerebrospinal fluid (CSF) and correlated this with clinical outcome to identify clinical markers of chronic radicular pain. Ten patients were recruited for the study. CSF lymphocyte frequencies and levels of cytokines, chemokines and growth factors were quantified using flow cytometry and enzyme-linked immunosorbent assay (ELISA), respectively. Clinical assessment utilised Brief Pain Inventory scores. Nine out of ten patients (90%) demonstrated significant reduction in pain severity (p = 0.0007) and pain interference scores (p = 0.0015) three months post-treatment. Our data revealed significant reductions in CD56+, CD3-, NK cell frequencies (p = 0.03) and IFN-γ levels (p = 0.03) in treatment responders, while CD8+ T cell frequencies (p = 0.02) and IL-6 levels were increased (p = 0.05). IL-17 inversely correlated with post-treatment pain severity score (p = 0.01) and pre and post-treatment pain interference scores (p = 0.03, p = 0.01). These results support the concept that chronic radicular pain is a centrally mediated neuroimmune phenomenon and the mechanism of action of DRG PRF treatment is immunomodulatory.

Percutaneous radiofrequency rhizotomy for cervical zygapophyseal joint mediated neck pain: A retrospective review of outcomes in forty-four cases.

BACKGROUND: Percutaneous radiofrequency (RF) rhizotomy of the medial branches of the dorsal rami from the spinal nerves is the standard treatment for cervical zygapophyseal joint mediated pain. There is a paucity of data regarding the longevity of analgesia following this procedure. OBJECTIVE: To determine the duration of complete pain relief, analgesic consumption and any adverse events following percutaneous cervical RF rhizotomy. METHODS: Retrospective chart review of patients who had undergone percutaneous cervical RF rhizotomy for zygapophyseal joint mediated neck pain. Patient reviews were undertaken by the pain consultant at 6 weeks, 6 months and 1 year following the procedure. Where follow-up was incomplete, the patient was assumed only to have had pain relief until their last review where complete pain relief had been documented. Analgesic consumption and any adverse events were recorded. The data was analysed using Microsoft Excel®. RESULTS: At 12 months 63.64% of patients were pain free. Median duration of complete pain relief was 52 weeks. Patients who experienced pain relief had ceased using prescription analgesia by their 6 week review. There were no repeat cervical RF rhizotomies, procedure related infections or unplanned hospital admissions. CONCLUSION: Percutaneous cervical RF rhizotomy is an effective treatment for cervical zygapophyseal joint mediated neck pain.