Review of Opioid Sparing Interventional Pain Management Options and Techniques for Radiofrequency Ablations for Sacroiliac Joint Pain.

PURPOSE OF REVIEW: The goal of this clinical review was to provide an update about the existing treatment options and associated evidence for various radiofrequency ablation techniques for sacroiliac joint pain. An electronic literature search on radiofrequency for the treatment of sacroiliac joint pain was conducted using PubMed, NCBI and Google Scholar. The following search keywords were used: radiofrequency ablation (cooled, pulsed, conventional, bipolar, intra-articular), sacroiliac joint and sacroiliac pain. The search was limited to human subjects, English language and articles with available full text. The bibliographic sections of all manuscripts were further searched for additional relevant citations. The full text of the relevant articles was reviewed by all the authors. RECENT FINDINGS: Our study showed that radiofrequency ablation is a safe and effective treatment option that can be utilized to manage sacroiliac joint pain. It offers accessibility to the primary care physician, reduces office visits with "pain" as the primary complaint and provides the added benefit of acting as a non-opioid sparing means of analgesia.

Vasovagal Reactions during Interventional Pain Management Procedures-A Review of Pathophysiology, Incidence, Risk Factors, Prevention, and Management.

Vasovagal reactions are a benign but common outcome of interventional pain management procedures that can negatively impact patient care, including aborted procedures and fear of future procedures that would otherwise help the patient. Research has been done on the incidence, risk factors, and management of vasovagal reactions resulting from such procedures, but less is known about how to prevent these reactions from occurring. In this paper, we present a literature review of the pathophysiology, incidence, risk factors, prevention, and management of vasovagal reactions during interventional pain management procedures, with an emphasis on the relative lack of research and conflicting advice on preventive measures. We found that moderate sedation and anxiolytics have been used prophylactically to prevent vasovagal reactions, but their side-effect profiles prevent them from being used commonly. Less studied is the prophylactic administration of antimuscarinics and IV fluids, despite the potential benefit of these measures and relatively low side-effect profile. We explore these topics here and offer advice for future research to fill the gaps in our knowledge.

Clinical Radiofrequency Ablation Outcomes of Combined Sensory Nerve Branch and Dorsal Entry Root Zone Complex Lesions for Sacroiliac Joint Complex Pain.

BACKGROUND: Chronic lower back pain (LBP) with or without leg pain (LP) is the most commonly reported anatomical site of pain among Canadian adults with chronic pain. A common cause for LBP and LP arises from dysfunction of the sacroiliac joint (SIJ) complex. When conventional medical management or rehabilitative efforts for SIJ-related LBP and LP fail to provide analgesia, pulsed radiofrequency (PRF) and/or radiofrequency ablation (RFA) of the dorsal entry root zone complex lesions (DREZC) and/or their more peripheral branches can also be a suitable means for treatment. Both PRF and RFA are interventional techniques that utilize heat to attenuate or ablate transmission of painful signals, respectively. The purpose of this chart review is to explore the clinical outcomes of patients experiencing SIJ-related pain who have undergone procedures with combined sensory nerve branch RFA and DREZC PRF lesions targeting the SIJ complex. METHODS: Following institutional review board approval, a retrospective chart review was performed from June 2018 to February 2021 for patients with LBP and/or LP refractory to physical rehabilitative efforts and medical management that underwent combined PRF and RF treatments for a diagnosis of SIJ complex pain. RF and PRF procedures were anatomically guided with the addition of sensory stimulation to ensure appropriate needle placement. Charts were reviewed for percentage of analgesia at final follow-up, duration of effect, degree of analgesia, patients' functional improvements, and changes in medication use patterns. RESULTS: Data was reviewed from 180 patients with LBP or LP who underwent combined PRF and RF treatments for a diagnosis of SIJ complex pain. The group consisted of 69 men and 111 women with a mean age of 59 years. All patients had lesions to their dorsal roots and/or branches (lumbar medial and sacral lateral), as determined using their pain profile as well as sensory stimulation. In the sample of 180 patients a total of 276 SIJs were treated over the period of data collection. Overall, 85.0% (n = 234) of procedures were considered successful with more than 50% analgesic relief at final follow-up. Of 234 successful outcomes, 110 reported ongoing analgesia (mean = 80.3% pain relief, SD ± 18.0) on the last date of follow up (mean = 53.2 days, SD ± 41.8) prior to being lost to follow-up. For patients not lost to follow-up, the mean amount of analgesia was reported to be 83.9% with an average duration of 86.3 days. Among all treatments, 6.9% (n = 19) provided no analgesic effect. Among the successful procedure outcomes, 54.4% (n = 150) reported increased activity/mobility, 24.3% (n = 67) reported improved sleep, 49.3% (n = 136) reported improved mood, and 11.6% (n = 32) reported decreased medication usage. Nine patients reported complications following the procedure. Complications included transient soreness, bruising, tenderness, myofascial pain, and two mild vagal responses without lasting sequelae. CONCLUSION: This review suggests that combined sensory nerve branch RFA and DREZC PRF lesions targeting the SIJ complex is a suitable intervention to treat SIJ-related LBP and/or LP refractory to physical rehabilitative efforts and medical management. Approximately 85% of these cases were successfully treated with the majority of patients report lasting analgesic effects with minimal complications, supporting the use of sensory stimulation-guided combined RF and PRF lesions for treatment of refractory SIJ complex pain.

Systematic Review of the Use of Intravenous Ketamine for Fibromyalgia.

Background: Fibromyalgia, a complex disorder that affects 1% to 5% of the population, presents as widespread chronic musculoskeletal pain without physical or laboratory signs of any specific pathologic process. The mechanism, while still being explored, suggests central sensitization and disordered pain regulation at the spinal cord and supraspinal levels, with a resulting imbalance between excitation and inhibition that may alter central nervous system nociceptive processing. Nociceptive hypersensitivity results from activity of the N-methyl-D-aspartate receptor (NMDAR)-mediated glutamatergic synaptic transmission in the spinal cord and brain. Because ketamine, an NMDAR antagonist, may reduce induction of synaptic plasticity and maintenance of chronic pain states, the study of its use in intravenous form to treat fibromyalgia has increased. Methods: We conducted a literature search with the objectives of examining the effect of intravenous ketamine administration on pain relief, identifying side effects, and highlighting the need for clinical studies to evaluate ketamine infusion treatment protocols for patients with fibromyalgia. We used the keywords "fibromyalgia," "chronic pain," "ketamine," "intravenous," and "infusion" and found 7 publications that included 118 patients with fibromyalgia who met inclusion criteria. Results: Clinical studies revealed a short-term reduction-only for a few hours after the infusions-in self-reported pain intensity with single, low-dose, intravenous ketamine infusions, likely attributable to nociception-dependent central sensitization in fibromyalgia via NMDAR blockade. Case studies suggest that increases in the total dose of ketamine and longer, more frequent infusions may be associated with more effective pain relief and longer-lasting analgesia. Another neurotransmitter release may be contributing to this outcome. Conclusion: This systematic review suggests a dose response, indicating potential efficacy of intravenous ketamine in the treatment of fibromyalgia.

Low-Dose Naltrexone (LDN)-Review of Therapeutic Utilization.

Naltrexone and naloxone are classical opioid antagonists. In substantially lower than standard doses, they exert different pharmacodynamics. Low-dose naltrexone (LDN), considered in a daily dose of 1 to 5 mg, has been shown to reduce glial inflammatory response by modulating Toll-like receptor 4 signaling in addition to systemically upregulating endogenous opioid signaling by transient opioid-receptor blockade. Clinical reports of LDN have demonstrated possible benefits in diseases such as fibromyalgia, Crohn's disease, multiple sclerosis, complex-regional pain syndrome, Hailey-Hailey disease, and cancer. In a dosing range at less than 1 µg per day, oral naltrexone or intravenous naloxone potentiate opioid analgesia by acting on filamin A, a scaffolding protein involved in µ-opioid receptor signaling. This dose is termed ultra low-dose naltrexone/naloxone (ULDN). It has been of use in postoperative control of analgesia by reducing the need for the total amount of opioids following surgery, as well as ameliorating certain side-effects of opioid-related treatment. A dosing range between 1 µg and 1 mg comprises very low-dose naltrexone (VLDN), which has primarily been used as an experimental adjunct treatment for boosting tolerability of opioid-weaning methadone taper. In general, all of the low-dose features regarding naltrexone and naloxone have been only recently and still scarcely scientifically evaluated. This review aims to present an overview of the current knowledge on these topics and summarize the key findings published in peer-review sources. The existing potential of LDN, VLDN, and ULDN for various areas of biomedicine has still not been thoroughly and comprehensively addressed.

Psychoneuroimmunological approach to gastrointestinal related pain.

BACKGROUND AND PURPOSE (AIMS): Psychoneuroimmunology is both a theoretical and practical field of medicine in which human biology and psychology are considered an interconnected unity. Through such a framework it is possible to elucidate complex syndromes in gastrointestinal related pain, particularly chronic non-malignant. The aim is to provide insight into pathophysiological mechanisms and suggest treatment modalities according to a comprehensive paradigm. The article also presents novel findings that may guide clinicians to recognize new targets or scientists to find new research topics. METHODS: A literature search of 'PubMed' and 'Google Scholar' databases was performed. Search terms included: 'Visceral pain', 'Psychoneuroimmunology', 'Psychoneuroimmunology and pain', 'Pain in GI system', 'GI related pain', 'Pain and microbiota', 'Enteric nervous system', 'Enteric nervous system and inflammation', 'CNS and pain', 'Inflammation and pain in GI tract', 'Neurogastroenterology', 'Neuroendocrinology', 'Immune system in GI pain'. After searching and reading sources deemed recent and relevant, a narrative review was written with a tendency to discriminate the peripheral, intermediate, and central pathophysiological mechanisms or treatment targets. RESULTS: Recent evidence point out the importance of considering the brain-gut axis as the main connector of the central and peripheral phenomena encountered in patients suffering from chronic non-malignant gastrointestinal related pain. This axis is also a prime clinical target with multiple components to be addressed in order for therapy to be more effective. Patients suffering from inflammatory bowel disease or functional gastrointestinal disorders represent groups that could benefit most from the proposed approach. CONCLUSIONS (BASED ON OUR FINDINGS): Rather than proceeding with established allopathic single-target central or peripheral treatments, by non-invasively modulating the brain-gut axis components such as the psychological and neuroendocrinological status, microbiota, enteric nervous system, or immune cells (e.g. glial or mast cells), a favourable clinical outcome in various chronic gastrointestinal related pain syndromes may be achieved. Clinical tools are readily available in forms of psychotherapy, prebiotics, probiotics, nutritional advice, and off-label drugs. An example of the latter is low-dose naltrexone, a compound which opens the perspective of targeting glial cells to reduce neuroinflammation and ultimately pain. IMPLICATIONS (OUR OPINION ON WHAT OUR FINDINGS MEAN): Current findings from basic science provide sound mechanistic evidence and once entering clinical practice should yield more effective outcomes for patients. In addition to well-established pharmacotherapy comprised notably of anti-inflammatories, antibiotics, and proton-pump inhibitors, valid treatment strategies may contain other options. These disease modulating add-ons include probiotics, prebiotics, food supplements with anti-inflammatory properties, various forms of psychotherapy, and low-dose naltrexone as a glial modulator that attenuates neuroinflammation. Clearly, a broader and still under exploited set of evidence-based tools is available for clinical use.

Lidocaine 5% Patch for Treatment of Acute Pain After Robotic Cardiac Surgery and Prevention of Persistent Incisional Pain: A Randomized, Placebo-Controlled, Double-Blind Trial.

OBJECTIVES: To test the hypotheses that lidocaine 5% patches decrease the severity of acute pain and incidence of persistent incisional pain after robotic cardiac valve surgery. DESIGN: A randomized, placebo-controlled, double-blind trial. SETTING: Tertiary care academic medical center. SUBJECTS: Patients having robotic cardiac valve surgery. METHODS: Patients having robotic cardiac valve surgery were randomly assigned to 5% lidocaine patches or identical-appearing placebo patches. Patches were applied around each incision 12 hours/day until pain resolved, or for 6 months. Supplemental opioid was provided by patient-controlled analgesia or orally. Pain was initially evaluated with a Visual Analog Scale, and subsequently by telephone with a Verbal Response Scale and the Pain Disability Index (our primary outcome) after 1 week, 1 month, 3 months, and 6 months. Global Perceived Effect, a measure of patient satisfaction, was simultaneously recorded. Repeated-measures analysis of variance and generalized estimating equations were our primary statistical tools. RESULTS: Acute pain scores and opioid use were low, as was the incidence of persistent pain. Lidocaine 5% patches did not influence any measure of acute or persistent incisional pain. Estimated difference (95% CI) in mean Pain Disability Index for Lidocaine patch minus placebo was -2.5 (95% CI -7.1, 2.1), P = 0.28. CONCLUSIONS: Lidocaine 5% patches did not reduce acute or persistent pain in patients having robotic thoracic surgery, though pain scores were low in both treatment groups. Clinicians should choose alternative analgesic approaches in these patients.

Radiofrequency intradiscal biacuplasty for treatment of discogenic lower back pain: a 12-month follow-up.

INTRODUCTION: Discogenic low back pain (LBP) affects a considerable number of patients suffering from chronic LBP. Recently, a growing interest has emerged in minimally invasive treatment options for discogenic LBP. Intradiscal biacuplasty (IDB), which uses cooled radiofrequency technology to ablate nociceptors in the posterior aspect of the intervertebral disc, is one such option. We previously presented 6-month results of a randomized, double-blinded, sham-controlled study. Now, we present the unblinded, 12-month follow-up data for treatment patients and 6-month data for cross-over subjects from the original sham group. METHODS: Physical function, pain relief, and disability were assessed using the Short Form-36, numerical rating scale, and Oswestry Disability Index, respectively. Subjects were unblinded at 6 months, and those initially randomized to sham procedure were given the option to cross over to IDB. RESULTS: Twenty-two out of 27 subjects in the original active treatment group were followed until 12 months and had clinically significant improvements in physical function (Δ = 22) and pain (Δ = -2.9). Out of 30 subjects originally in the sham group, 24 chose to cross over, and 20 cross-over patients completed follow-up at 6 months. In cross-over patients, improvements in physical function and pain did not differ statistically from those of patients originally randomized to IDB treatment. No complications or adverse events related to the procedure were reported. CONCLUSIONS: Clinically significant improvements after IDB initially reported at 6 months were maintained at 9 and 12 months. The cross-over subjects had similar improvement in all outcome measures at all observed time points.

A randomized, placebo-controlled trial of transdiscal radiofrequency, biacuplasty for treatment of discogenic lower back pain.

OBJECTIVE: The aim was to compare the efficacy of intradiscal biacuplasty (IDB) with that of placebo treatment for discogenic low back pain. DESIGN: This is a randomized, placebo-controlled trial. Subjects were randomized on a 1:1 basis to IDB and sham groups. Follow-ups were conducted at 1, 3, and 6 months. Subjects and coordinators were blinded to randomization until 6 months. Of the 1,894 subjects screened, 64 subjects were enrolled, and 59 were treated: 29 randomized to IDB and 30 to sham. All subjects had a history of chronic low back pain for longer than 6 months. INTERVENTIONS: Two cooled radiofrequency (RF) electrodes placed in a bipolar manner in affected discs to lesion the nociceptive fibers of the annulus fibrosus. The sham procedure was identical to the active treatment except that probes were not directly inserted into the disc space, and RF energy was not actively delivered. RESULTS: The principal outcome measures were physical function, pain, disability, and opioid usage. Patients in the IDB group exhibited statistically significant improvements in physical function (P = 0.029), pain (P = 0.006), and disability (P = 0.037) at 6-month follow-up as compared to patients who received sham treatment. Treatment patients reported a reduction of 16 mg daily intake of opioids at 6 months; however, the results were not statistically different from sham patients. CONCLUSIONS: The results suggest that the clinical benefits observed in this study are the result of non-placebo treatment effects afforded by IDB. IDB should be recommended to select the patients with chronic discogenic low back pain. (Clinicaltrials.gov number, NCT00750191.).

Glossopharyngeal neuralgia secondary to vascular compression in a patient with multiple sclerosis: a case report.

INTRODUCTION: Glossopharyngeal neuralgia is an uncommon, painful syndrome, characterized by paroxysms of pain in the sensory distribution of the 9th cranial nerve. Idiopathic glossopharyngeal neuralgia may be due to compression of the glossopharyngeal nerve by adjacent vessels, while secondary glossopharyngeal neuralgia is associated with identifiable lesions affecting the glossopharyngeal nerve at different levels of its neuroanatomic pathway. Glossopharyngeal neuralgia is rare in the general population, but is more common in patients with multiple sclerosis. CASE PRESENTATION: A 56-year-old Caucasian woman with multiple sclerosis and migraine presented to our facility with intermittent lancinating pain to the right of her throat, tongue, and the floor of her mouth that had been occurring for the past year. The pain was intense, sharp, and stabbing, which lasted two to six seconds with radiation to the right ear. Initially, the attacks were infrequent, however, they had become more intense and frequent over time. Our patient reported weight loss, headache, painful swallowing, and the inability to maintain sleep due to painful attacks. A neurological examination revealed a right-handed woman with trigger points in the back of the tongue and throat on the right side. She also had dysphagia, hoarseness, and pain in the distribution of the right glossopharyngeal nerve. Mild right hemiparesis, hyperreflexia, dysmetria, and an ataxic gait were present. A magnetic resonance imaging scan of the brain was consistent with multiple sclerosis and magnetic resonance angiography demonstrated a loop of the posterior inferior cerebellar artery compressing the right glossopharyngeal nerve. She responded satisfactorily to carbamazepine. Microvascular decompression and Gamma Knife® radiosurgery were discussed in case of failure of the medical treatment; however, she declined these options. CONCLUSIONS: Glossopharyngeal neuralgia in multiple sclerosis may occur due to vascular compressive lesions and it should not be solely attributed to the underlying demyelinating process. Vascular compression of the glossopharyngeal nerve could independently cause glossopharyngeal neuralgia in patients with multiple sclerosis, and vascular imaging to exclude such a diagnosis is recommended.

Evidence-based knee injections for the management of arthritis.

OBJECTIVE: Arthritis of the knee affects 46 million Americans. We aimed to determine the level of evidence of intraarticular knee injections in the management of arthritic knee pain. METHODS: We systematically searched PUBMED/MEDLINE and the Cochrane databases for articles published on knee injections and evaluated their level of evidence and recommendations according to established criteria. RESULTS: The evidence supports the use of intraarticular corticosteroid injections for rheumatoid arthritis (1A+ Level), osteoarthritis (1A+ Level), and juvenile idiopathic arthritis (2C+ Level). Pain relief and functional improvement are significant for months up to 1 year after the injection. Triamcinolone hexacetonide offers an advantage over triamcinolone acetonide and should be the intraarticular steroid of choice (2B+ Level). Intraarticular injection of hyaluronate may provide longer pain relief than steroid injection in osteoarthritis (2B+ Level). It can also be effective for rheumatoid arthritis knee pain (1A+ Level). However, it is only recommended for patients with significant surgical risk factors and for patients with mild radiographic disease in whom conservative treatment has failed (2B± Level). Botulinum toxin type A injection is effective in reducing arthritic knee pain (2B+ Level), and so is tropisetron (2B+ Level) and tanezumab (2B+ Level). The new agents, such as rAAV2-TNFR:Fc, SB-210396/CE 9.1, and various radioisotopes have provided various degrees of success, but their long-term safety and efficacy remains to be determined. CONCLUSIONS: We conclude that strong evidence supports the use of intraarticular knee injection as a valuable intervention in the continuum of management of arthritis between conservative treatment and knee surgeries.

Differential epidural block predicts the success of visceral block in patients with chronic visceral abdominal pain.

BACKGROUND AND AIMS: Differential thoracic epidural regional block, also known as a differential neural block (DNB), involves the placement of an epidural catheter placed in the thoracic epidural space to achieve appropriate anesthesia in a dermatomal distribution. This is a retrospective case series evaluating how well a DNB may predict success of subsequent visceral blockade in patients with chronic abdominal pain of visceral origin. METHODS: Of 402 patients who had a DNB performed for unexplained abdominal pain from January 2000 to January 2009, 81 patients were found to have results consistent with visceral pain and thus underwent subsequent visceral blockade. Basic demographic data, years of chronic pain, history of psychosocial issues, initial visual analog scale (VAS) pain score, pain location, and medication usage were documented in our electronic medical record database. Parameters regarding DNB and visceral blocks also were documented. Descriptive statistics were computed for all variables. The positive predictive value (PPV) for DNB for whom visceral block was successful (at least a 50% reduction in VAS) was calculated. Additionally, subjects with successful visceral blocks were compared to those with unsuccessful visceral blocks. PARTICIPANTS: All patients with chronic abdominal pain with normal gastrointestinal studies who underwent DNB. SETTING: Tertiary Outpatient Pain Management Clinic. DESIGN: Retrospective Cohort Study. RESULTS: Mean age of patients was 46 (± 15) years, 73% were female, and median duration of pain was 5 years. 67% of subjects were taking opioid analgesics. PPV of DNB was 70.4%. Only factor found to be statistically significant with visceral block success was baseline VAS with higher scores associated with DNB predictive success (6.8 ± 1.7 vs. 5.5, 1.8; P = 0.004). Use of membrane stabilizing medications was significantly more common in subjects for whom visceral block was not successful (46% vs. 25%; P = 0.058). Area underneath curve (AUC) for VAS was found to be 0.70 (95% CI: 0.57, 0.82), which signifies fair discrimination. CONCLUSION: Differential neural block is fairly predictive of subsequent visceral block success in patients with chronic abdominal pain of visceral origin. An initial VAS ≥ 5 provides a sensitivity of 93%, which implies that VAS < 5 may predict unsuccessful visceral block. Contrarily, a value of ≥ 8 would provide a specificity of 92% and may be used to predict success of subsequent visceral block.