REVIEW | doi:10.20944/preprints202106.0200.v2
Subject: Medicine & Pharmacology, Allergology Keywords: Neuropathic Pain; Combination Therapy; Pharmacotherapy; Randomized Control Trial
Online: 2 August 2021 (14:52:46 CEST)
Pharmacological treatment is not very effective for neuropathic pain (NP). A progressive decrease in the estimated effect of NP drugs has been reported, giving rise to an increase in the use of the multimodal analgesic approach. We performed a new, independent review to assess whether more evidence and of better-quality has become available since the last systematic review. We evaluated the efficacy, tolerability, and safety of double-blinded, randomized, controlled trials involving only adult participants and comparing combination therapy (CT: ≥ 2 drugs) to a placebo and/or at least one other comparator with an NP indication. The primary outcome assessed was the proportion of participants reporting ≥50% pain reductions from baseline. The secondary outcome assessed was the proportion of drop-outs due to treatment-emergent adverse events. After removing duplicates, 2323 citations were screened, with 164 articles assessed for eligibility, from which 16 were included for qualitative analysis. From the latter, only five lasted for at least 12 weeks and only six complied with the required data for complete analysis. CT has been adopted for years without robust evidence. Efforts have been made to achieve better-quality evidence, but the quality has not improved over the years. In this regard, guidelines for NP should attempt to make recommendations about CT research, prioritizing which combinations to analyze.
REVIEW | doi:10.20944/preprints202001.0148.v1
Subject: Medicine & Pharmacology, Clinical Neurology Keywords: nerve hydrodissection; pain management; ultrasonography; neuropathic pain
Online: 15 January 2020 (12:09:56 CET)
Nerve hydrodissection (HD), a technique used when treating nerve entrapments, involves using an anesthetic or solution such as saline or 5% dextrose solution to separate the nerve from the surrounding tissue, fascia, or adjacent structures. This technique aims to treat neuropathic pain, or pain caused by the nerve. Ultrasound-guided HD of peripheral nerves has gained significant attention in the medical profession and pain management fields in recent years. This is due to a number of high impact publications of randomized control trials demonstrating the efficacy and safety of this technique for the treatment of carpal tunnel syndrome. Even the 20th edition of Harrison’s Principles of Internal Medicine textbook lists injection of 5% dextrose as an alternative local treatment that does not have the side effects of corticosteroids. At present, there is no review of the current literature on this technique. This manuscript will summarize and discuss the following: 1) the different approaches to doing ultrasound-guided HD of nervous structures, 2) its usages in different clinical situations, 3) its clinical pearls, 4) the solution used, and 5) the postulated mechanisms of action.
REVIEW | doi:10.20944/preprints202106.0128.v1
Subject: Medicine & Pharmacology, Allergology Keywords: chronic pain; nociceptive pain; neuropathic pain; nociplastic pain; psychogenic pain; neuroinflammation; kynurenine
Online: 4 June 2021 (09:09:26 CEST)
Chronic pain is an unpleasant sensory and emotional experience that persists or recurs more than three months and may extend beyond the expected time of healing. Recently nociplastic pain has been introduced as a descriptor of mechanism of pain, which is due to disturbance of neural processing without actual or potential tissue damage, appearing to replace a concept of psychogenic pain. An interdisciplinary task force of the International Association for the Study of Pain (IASP) compiled a systematic classification of clinical conditions associated with chronic pain, which was published in 2018 and will officially come into effect in 2022 in the 11th revision of the International Statistical Classification of Diseases and Related Health Problems (ICD-11) by the World Health Organization. ICD-11 offers the option for recording the presence of psychological or social factors in chronic pain; however, cognitive, emotional, and social dimensions in the pathogenesis of chronic pain are missing. Earlier pain disorder was defined as a condition with chronic pain associated with psychological factors, but it was replaced with somatic symptom disorder with predominant pain in Diagnostic and Statistical Manual of Mental Disorders, 5th Edition (DSM-5) in 2013. Recently clinical nosology is trending toward highlighting neurological pathology of chronic pain, discounting psychological or social factors in the pathogenesis of pain. This review article discusses components of the pain pathway, the component-based mechanisms of pain, central and peripheral sensitization, roles of chronic inflammation, and the involvement of tryptophan-kynurenine pathway metabolites, exploring participations of psychosocial and behavioral factors in central sensitization of diseases progressing into development of chronic pain, comorbid diseases that commonly present a symptom of chronic pain, and psychiatric disorders that manifest chronic pain without obvious actual or potential tissue damage.
ARTICLE | doi:10.20944/preprints201911.0101.v1
Subject: Medicine & Pharmacology, Anesthesiology Keywords: chronic pain; epigenetics; neuropathic pain; postoperative pain; thoracic surgery; video-assisted
Online: 10 November 2019 (09:29:13 CET)
Background: Elucidation of epigenetic mechanisms correlating with neuropathic pain in humans is crucial for the prevention and treatment of this treatment-resistant pain state. In the present study, associations between neuropathic pain characteristics and DNA methylation of the transient receptor potential ankyrin 1(TRPA1) gene were evaluated in chronic pain patients and preoperative patients. Methods: Pain and psychological states were prospectively assessed in patients who suffered chronic pain or were scheduled for thoracic surgery. Neuropathic characteristics were assessed using the Douleur Neuropathique 4 (DN4) questionnaire. DNA methylation levels of the CpG island in the TRPA1 gene were examined using whole blood. Results: Forty-eight adult patients were enrolled in this study. Increases in DNA methylation rates at CpG -51 showed positive correlations with increases in the DN4 score both in preoperative and chronic pain patients. Combined methylation rates at CpG -51 also significantly increased together with increase in DN4 scores. Conclusions: Neuropathic pain characteristics are likely associated with methylation rates at the promoter region of the TRPA1 gene in human peripheral blood.
ARTICLE | doi:10.20944/preprints202008.0389.v1
Subject: Medicine & Pharmacology, Pharmacology & Toxicology Keywords: ECN; neuropathic pain; oxidative stress; apoptosis; myelin sheath; spectroscopy
Online: 18 August 2020 (12:00:15 CEST)
7β-(3-ethyl-cis-crotonoyloxy)-1α-(2-methylbutyryloxy)-3,14-dehydro-Z-notonipetranone (ECN), a sesquiterpenoid obtained from a natural origin (Tussilago farfara)has proved to be effective in minimizing various side effects associated with opioids and nonsteroidal anti-inflammatory drugs. The current study focused on investigating the effects of ECN on neuropathic pain induced by partial sciatic nerve ligation (PSNL) by mainly focusing on oxidative stress, inflammatory and apoptotic proteins expression in mice. Neuropathic pain was induced in mice by PSNL surgery performed on day 1 and ECN (1 and 10 mg/kg, i.p.), was administered once daily for 11 days, starting from the third day after surgery. ECN post-treatment was found to reduce hyperalgesia and allodynia in a dose dependent manner. ECN significantly reversed the severity of neuropathic pain by improving distress symptoms and survival rate. ECN remarkably reversed the histopathological abnormalities associated with oxidative stress, apoptosis and inflammation. Furthermore, ECN prevented the suppression of antioxidants (glutathione, glutathione-S-transferase, catalase, superoxide dismutase, NF-E2-related factor-2 (Nrf2), hemeoxygenase-1 and NAD(P)H: quinone oxidoreductase) by PSNL. Moreover, pro-inflammatory cytokines (tumor necrotic factor alpha, interleukin 1 beta, interleukin 6, cyclooxygenase-2 and inducible nitric oxide synthase) expression was reduced by ECN administration. Treatment with ECN was successful in reducing caspase-3 level consistent with the observed modulation of pro-apoptotic proteins. Additionally, ECN showed protective effect on the lipid content of myelin sheath as evident from FTIR spectroscopy which showed the shift of lipid component bands to higher values. Thus, anti-neuropathic potential of ECN might be due to inhibition of oxidative stress, inflammatory mediators and pro-apoptotic proteins.
REVIEW | doi:10.20944/preprints202301.0034.v1
Subject: Medicine & Pharmacology, Clinical Neurology Keywords: migraine; neuropathic pain; calcitonin gene-related peptide (CGRP); kynurenine; glia; cytokines; neuroinflammation; transient receptor potential (TRP) ion channels; endocannabinoids
Online: 4 January 2023 (01:53:45 CET)
Migraine and neuropathic pain (NP) are evocative of painful, disabling, chronic conditions which exhibit resembling symptoms and thus considered to share a common etiology. Calcitonin gene-related peptide (CGRP) has gained credit as a target for migraine management; nevertheless, the efficacy and the applicability of CGRP modifiers warrant search for more effective therapeutic targets for pain management. This scoping review overviews human studies of common pathogenic factors in migraine and NP to explore potential novel therapeutic targets. CGRP causes inflammation in the meninges; monoclonal antibodies and inhibitors target CGRP. Gluta-mate-induced hyperexcitability and subsequent sensitization are closely linked to an alteration of the tryptophan (Trp)-kynurenine (KYN) metabolic system; the Trp-KYN system may serve as a potential target. Microglial overaction is observed in migraine and NP; modifying the microglial activity may be a possible approach. Cytokine-induced inflammation is a leading hypothesis of the pathogenesis of the conditions; alleviating neuroinflammation may complement a pain-relieving armamentarium. Transient receptor potential (TRP) ion channels evoke the release of several substances; TRP ion channels may potentially emerge as new targets. The endocannabinoid system plays a major role in the pain trafficking pathway; modification of the system may open a new path toward discovery of new analgesics. Here we highlight the mechanism of those common pathogenic factors to explore therapeutic targets for innovative pain management in migraine and NP.
ARTICLE | doi:10.20944/preprints202209.0178.v1
Subject: Medicine & Pharmacology, Anesthesiology Keywords: chronic postoperative pain; erector spinae plane block; coronary artery bypass grafting; Neuropathic Pain Symptom Inventory
Online: 13 September 2022 (11:24:28 CEST)
Up to 56% of patients develop chronic postsurgical pain (CPSP) after coronary artery bypass grafting (CABG). CPSP can affect patients’ moods and decrease daily activities. The primary aim of this study was to investigate CPSP severity in patients following off-pump (OP)-CABG using the Neuropathic Pain Symptom Inventory (NPSI). This was a prospective cohort study conducted in a cardiac surgery department of a teaching hospital. Patients undergoing OP-CABG were enrolled in an erector spinae plane block (ESPB) group (n = 27) or a control (CON) group (n = 24). Before the induction of general anesthesia, ESPB was performed on both sides under ultrasound guidance using 0.375% ropivacaine. The secondary outcomes included cumulative oxycodone consumption, acute pain intensity, mechanical ventilation time, hospital length of stay, and postoperative complications. CPSP intensity was lower in the ESPB group than in the CON group 1, 3, and 6 months postsurgery (p < 0.001). Significant between-group differences were also observed in other outcomes, including postoperative pain severity, opioid consumption, mechanical ventilation time, and hospital length of stay in favor of the ESPB group. Preemptive ESPB appears to decrease the risk of CPSP development in patients undergoing OP-CABG. Reduced acute pain severity and shorter mechanical ventilation times and hospital stays should improve patients’ satisfaction and reduce perioperative complications.
REVIEW | doi:10.20944/preprints202210.0083.v1
Subject: Medicine & Pharmacology, Pathology & Pathobiology Keywords: epigenetics; TRP channels; TRPA1; pain transmission; neuropathic pain; neurogenic inflammation; migraine; DNA methylation; histone modification; micro RNA
Online: 7 October 2022 (15:21:34 CEST)
Background: Transient receptor potential cation channel subfamily A member 1 (TRPA1) is expressed in trigeminal neurons and brain regions important in migraine pathogenesis and is activated by many migraine triggers. Epigenetic regulation of TRPA1 expression is important in pain transmission and neurogenic inflammation.Findings: TRPA1 channels change noxious stimuli into pain signals with the involvement of epigenetic regulation, including DNA methylation, histone modifications, and effects of micro RNAs (miRNAs) and long non-coding RNAs. TRPA1 may change epigenetic profile of many pain-related genes as it may modify enzymes establishing the epigenetic profile and expression of non-coding RNAs. TRPA1 may induce the release of calcitonin gene related peptide (CGRP), from trigeminal neurons and dural tissue. Therefore, epigenetic regulation of TRPA1 may play a role in efficacy and safety of anti-migraine therapies targeting TRP channels and CGRP. TRPA1 is also involved in neurogenic inflammation, important in migraine. The fundamental role of TRPA1 in inflammatory pain transmission may be epigenetically regulated. Conclusions: Epigenetic connections of TRPA1 may play a role in efficacy and safety of anti-migraine therapy targeting TRP channels or CGRP and they should be further explored for efficient and safe antimigraine treatment.
ARTICLE | doi:10.20944/preprints202105.0495.v1
Subject: Medicine & Pharmacology, Allergology Keywords: nephrectomy; Neuropathic Pain Symptom Inventory; patient-controlled analgesia; quadratus lumborum block; persistent postoperative pain
Online: 20 May 2021 (17:17:47 CEST)
Background: New regional techniques can improve pain management after nephrectomy. Methods: This study was a randomized controlled trial conducted at two teaching hospitals. Patients undergoing elective open and laparoscopic nephrectomy were eligible to participate in the trial. A total of 100 patients were divided into a quadratus lumborum block (QLB) group and a control (CON) group. At the end of surgery, but while still under general anesthesia, unilateral QLB with ropivacaine was performed on the side of nephrectomy for patients in the QLB group. The main measured outcome of this study was oxycodone consumption via a patient-controlled anesthesia (PCA) pump during the first 24 hours following surgery; other measured outcomes included postoperative pain intensity assessment, patient satisfaction with pain management, and persistent pain evaluation. Results: Patients undergoing QLB needed less oxycodone than those in the CON group (34.5 mg [interquartile range 23–40 mg] vs. 47.5 mg [35–50 mg]; p<0.001). No difference between the groups was seen in postoperative pain intensity measured on the visual analog scale, except for the evaluation at hour 2, which was in favor of the QLB group (p=0.03). Patients who received QLB were more satisfied with postoperative pain management than the CON group. Persistent postoperative pain was assessed with the Neuropathic Pain Symptom Inventory (NPSI) at months 1, 3, and 6 and was found to be significantly lower in the QLB group at each evaluation (p<0.001). We also analyzed the impact of the surgery type on persistent pain severity, which was significantly lower after laparoscopic procedures than open procedures at months 1, 3, and 6. Conclusions: QLB reduces oxycodone consumption in patients undergoing open and laparoscopic nephrectomy and decreases persistent pain severity months after hospital discharge.
REVIEW | doi:10.20944/preprints201808.0293.v1
Subject: Medicine & Pharmacology, Oncology & Oncogenics Keywords: Keywords: palliative care, child, brain, neoplasm, neuropathic pain, pain, symptoms, hospice
Online: 16 August 2018 (15:14:46 CEST)
Children with central nervous system (CNS) malignancies often suffer from high symptom burden and risk of death. Pediatric palliative care is a medical specialty, provided by an interdisciplinary team, which focuses on enhancing quality of life and minimizing suffering for children with life-threatening or life-limiting disease, and their families. Primary palliative care skills which include basic symptom management, facilitation of goals-of-care discussions, and transition to hospice can and should be developed by all providers of neuro-oncology care. This chapter will review the fundamentals of providing primary palliative care
CASE REPORT | doi:10.20944/preprints202208.0165.v1
Subject: Medicine & Pharmacology, Clinical Neurology Keywords: neuralgia; earache; facial pain; neuropathic pain; geniculate neuralgia; nervus intermedius; otalgia; gabapentin
Online: 9 August 2022 (03:20:29 CEST)
(1) Background: Painful nervus intermedius neuropathy (e.g., geniculate neuralgia) involves continuous or near-continuous pain affecting the distribution of the intermedius nerve(s). The diagnosis of this entity is challenging, particularly when the clinical and demographic features do not resemble the typical presentation of this condition. To the best of our knowledge, only three case reports have described the occurrence of nervus intermedius neuropathy in young patients. (2) Case Description: A 13-year-old female referred to the Orofacial Pain clinic with a complaint of pain located deep in the right ear and mastoid area. The pain was described as a constant throbbing and dull, with an intensity of 7/10 on numerical rating scale, characterized by superimposed brief paroxysms of severe sharp pain. The past treatments included ineffective pharmacological and irreversible surgical approaches. After a comprehensive evaluation, a diagnosis of idiopathic painful nervus intermedius neuropathy was given, which was successfully managed with the use of gabapentin. (3) Conclusions and Practical Implications: The diagnosis and treatment of neuropathic pain affecting the nervus intermedius can be challenging due to the complex nature of the sensory innervation of the ear. The diagnosis can be even more challenging in cases of atypical clinical and demographic presentations, which in turn may result in unsuccessful, unnecessary, and irreversible treatments. Multidisciplinary teams and constant knowledge update are fundamental to provide good quality of care to our patients and to not overlook any relevant signs or symptoms.
ARTICLE | doi:10.20944/preprints202003.0116.v1
Subject: Medicine & Pharmacology, Anesthesiology Keywords: continuous epidural infusion; dexamethasone; dexamethasone pulse therapy; inflammation; local anesthetics; neuropathic pain; postherpetic neuralgia
Online: 7 March 2020 (03:22:47 CET)
The most common complication of herpes zoster is postherpetic neuralgia (PHN), which is accompanied by severe pain that lowers patients’ quality of life. Although epidural injection of local anesthetics and steroids is effective in controlling neuropathic pain resulting from herpes zoster, few studies report the efficacy and safety of epidural steroid administration in PHN patients. We randomly assigned 42 patients with severe PHN pain (visual analog scale (VAS) score ≥7) to receive continuous epidural infusion of local anesthetics with either a one-time bolus of 5 mg dexamethasone or dexamethasone pulse therapy. VAS scores significantly decreased over time for all patients, but the reduction in VAS scores and likelihood of achieving complete remission were significantly greater among patients who received dexamethasone pulse therapy, without any adverse effects. These results show that continuous epidural infusion of local anesthetics with dexamethasone is effective and safe for reducing PHN pain and promoting complete remission and that more pronounced beneficial effects are associated with more intense epidural steroid administration.
ARTICLE | doi:10.20944/preprints202207.0361.v1
Subject: Medicine & Pharmacology, Anesthesiology Keywords: PSPS; FBSS; SCS; surgical lead; SCS implantation; MAST (for Minimal Access Spine Technologies); TCIVA (for Target Controlled Intra-Veinous Anesthesia); composite score; pain mapping; neuropathic pain; chronic pain; quality of life; anesthesia; hypnosis
Online: 25 July 2022 (08:34:26 CEST)
Spinal Cord Stimulation (SCS) is an effective and validated treatment to address chronic refractory neuropathic pain in Persistent Spinal Pain Syndrome-Type 2 (PSPS-T2) patients. Surgical SCS lead placement is traditionally performed under general anesthesia due to its invasiveness. In parallel, recent works have suggested that Awake Anesthesia (AA), consisting in Target Controlled Intra-Veinous Anesthesia (TCIVA), could be an interesting tool to optimize lead anatomical placement using patient intra-operative feedback. We hypothesized that combining AA with Minimal Invasive Surgery (MIS) could improve SCS outcomes. The goal of this study was to evaluate SCS lead performance (defined by the area of pain adequately covered by paraesthesia generated via SCS), using an intraoperative objective quantitative mapping tool, and secondarily to assess pain relief, functional improvement and change in quality of life with a composite score. We analyzed data from a prospective multicenter study (ESTIMET) to compare the outcomes of 115 patients implanted with MIS under AA (MISAA group) or General Anesthesia (MISGA group), or by Laminectomy under General Anesthesia (LGA group). All in all, MISAA appears to show significantly better performance in terms of patient pain coverage, as well as improved secondary outcomes. One step further, our results suggest that MISAA combined with intra-operative hypnosis could potentialize patient intraoperative cooperation and could be proposed as a personalized package offered to PSPS-T2 patients eligible for SCS implantation in highly dedicated neuromodulation centers.