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Background: Wireless percutaneous nerve stimulation (PNS) for chronic pain is rapidly evolving in the ever expanding neuromodulation paradigm. Safety and lower risks with a potential of long-term analgesia cannot be over emphasised especially with the ongoing opioid pandemic. PNS with an implanted pulse generator (IPG) has also been shown to provide good benefit, without often unpleasant widespread paraesthesia from conventional spinal cord stimulators. Aim and Methods: We retrospectively extracted data on all wireless PNS implants in our highly specialised pain neuromodulation centre since initiation of wireless PNS service in August 2019. Patient demographics, pain history, analgesic intake and details on implant follow-up data within 1 year post-implant including pain relief, EuroQol-5 Dimension (EQ-5D) and Patients' Global Impression of Change (PGIC) scores were extracted. The cases are presented in a narrative format. Result: A total of five patients were implanted with wireless (Stimwave®) PNS from August 2019 to February 2020. Neuropathic pain was the most common presenting diagnosis. All patients showed >50% pain relief at 3 months. EQ-5D and PGIC did not show any improvement in the subjects. Two of the patients managed to decrease their analgesics after implantation. Similar sustained benefits could not be demonstrated after 1 year. Discussion: PNS can provide analgesia in appropriately selected cases. Naivety of the technique and procedure might cause some degree of uncertainty. External pulse generator with wireless transmission avoids IPG and tunnelling related side effects, but requires individualised special wearable technology to power the lead. Minimally invasive nature of the technique might be attractive and preferable for patients with complex medical issues, nickel allergy and poor general health who may otherwise be unsuitable for Spinal Cord Stimulation (SCS) with conventional hardware. Robust prospective controlled studies and RCTs in future might provide further insights on utility in other neuropathic pain diagnosis, long-term outcomes and acceptability compared to conventional SCS.
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Objective: Abdominal Cutaneous Nerve Entrapment Syndrome (ACNES) is a common but under recognised cause of chronic abdominal wall Pain. This survey was carried out to understand the clinical course of the condition following interventions such as nerve blocks and surgical release of entrapped nerve. Design: Retrospective, Cross-sectional survey. Setting: Pain Management clinic at University teaching hospital. Subjects: Adult patients who had interventions either nerve block or surgical release over a 6 year period. Methods: After written informed consent, participants completed a questionnaire including Brief Pain Inventory (BPI), quality of health measure (EQ-5D-5L), and global impression of change scale as well as open-ended question about the outcomes. Baseline demographics, details of pain condition, interventions received were collected from the health records. Results: The diagnosis of ACNES was established in 85.2% by ultrasound guided injections. The injection therapy with local anaesthetic and steroid was successful to 75.8% while the surgical release was successful in 90%. The cumulative duration of pain relief varied from 3 weeks to 5 years. A significant difference was noted in BPI (p = 0.001), EQ-5D-5L (p = 0.002) and health thermometer (p = 0.009) post interventions. Conclusions: Ultrasound guided injections aid the accurate diagnosis of ACNES. Appropriate treatment of ACNES improves both pain control and quality of life.
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BACKGROUND AND OBJECTIVE: Studies have reported relief of chronic shoulder pain with non-ablative pulsed neuromodulatory (pRF) or ablative radiofrequency (aRF) procedures on innervation of the shoulder joint but interpretation of these reports is hampered by inconsistent indications, anatomic targets and follow-up. This systematic review was conducted to synthesize the existing literature on procedures employing pRF or aRF for treating chronic shoulder pain. DATABASES AND DATA TREATMENT: MEDLINE and other medical literature databases were reviewed up to 31 December 2019 for publications on pRF or aRF procedures on shoulder joint innervation to relieve chronic pain. Data on analgesic and functional outcomes measured at any time point following the interventions were extracted. Existing knowledge on innervation of the shoulder joint with relevance to RF procedures was also synthesized. RESULTS: In all, 42 publications, 7 randomized controlled trials (RCTs) and 35 observational studies, case series or reports were identified. Thirty-six of these publications were on pRF procedure and 29 of these reported procedures exclusively targeting the suprascapular nerve. A meta-analysis of the seven RCTs evaluating pRF indicated no analgesic benefit or functional improvement with this treatment over conventional medical management. Case series and reports on aRF indicate a potential for analgesic benefit but the quality of this evidence was low. CONCLUSIONS: RF treatments targeting the sensory innervation of the shoulder joint affected by degenerative conditions have the potential to reduce pain but the current evidence does not suggest analgesic or functional benefit (GRADE certainty of evidence-low). Studies of high methodological quality are required to further investigate the role of these interventions. SIGNIFICANCE: This is a comprehensive review of literature on pulsed (non-ablative) and ablative radiofrequency (RF) procedures for chronic shoulder pain. The systematic review and meta-analysis of 7 trials found that pulsed RF for chronic shoulder pain provided similar analgesia and functional improvement as conservative medical management at three months after the procedures. The case series and reports on ablative RF for shoulder pain indicate possible analgesic benefit but their quality was low. This review highlights the need for studies of a high quality on ablative RF treatments for chronic shoulder pain.