PAIN Report

Functional and histological improvements of small nerve neuropathy after high-concentration capsaicin patch application: A case study Introduction: Small fiber neuropathy has been found to occur in a large variety of pathological onditions, and the gold standard for diagnosis of small fiber neuropathy is skin biopsy. Sudorimetry is now considered an accurate technique to evaluate small fiber function with a good sensitivity and specificity for the diagnosis of small fiber neuropathy. Capsaicin high-concentration patch is approved for the treatment of peripheral neuropathic pain in adults either alone or in combination with other medicinal products for pain. Methods: We describe the case of a 50-year-old woman diagnosed with small fiber neuropathy. After 2 previous treatment failures, she was proposed a treatment with high-dose capsaicin patches on the sole of her foot. The patient experienced an important diminution of her neuropathic pain. There was a 50% decrease in the pain numeric scale. Electrochemical skin conductance and skin biopsy were repeated 3 months after patch application. Results: At 3 months, the patient then experienced an important diminution of her neuropathic pain, electrochemical skin conductance had normalized both in the hands and feet and intraepidermal nerve fiber density at distal leg increased almost reaching normal range. Conclusion: This case report shows the correlation between clinical improvement, electrochemical skin conductance normalization, and intraepidermal nerve fiber density improvement after a high-dose capsaicin patch in a patient with small fiber neuropathy. Corresponding author. Address: Centre d'Evaluation et Traitement de la Douleur, Hôpitaux Universitaire Paris Centre, Cochin, 27, Rue du Faubourg Saint Jacques, 75014 Paris, France. Tel.: +33 1 58 41 26 24; fax: +33 1 58 41 15 55. E-mail address: annepriscille.trouvin@aphp.fr (A.-P. Trouvin). Sponsorships or competing interests that may be relevant to content are disclosed at the end of this article. Received February 14, 2019 Received in revised form May 04, 2019 Accepted May 08, 2019 This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives License 4.0 (CCBY-NC-ND), where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially without permission from the journal. © 2019 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of The International Association for the Study of Pain.

Peripheral nerve pathology in sickle cell disease mice Introduction: Many patients with sickle cell disease (SCD) suffer from chronic pain, which is often described as neuropathic in nature. Although vascular and inflammatory pathology undoubtedly contribute to the SCD pain experience, the nociceptive signals that ultimately drive symptoms are detected and transmitted by peripheral sensory neurons. To date, no systematic histological examination of peripheral nerves has been completed in patients or mouse models of SCD to diagnose disease-related neuropathy. Objectives: In this brief report, we compared peripheral nerve morphology in tissues obtained from Berkeley transgenic SCD mice and control animals. Methods: Sciatic nerves were visualized using light and transmission electron microscopy. Myelin basic protein expression was assessed through Western blot. Blood–nerve barrier permeability was measured using Evan's blue plasma extravasation. Results: Peripheral fibers from SCD mice have thinner myelin sheaths than control mice and widespread myelin instability as evidenced by myelin sheath infolding and unwrapping. Deficits are also observed in nonmyelinating Schwann cell structures; Remak bundles from SCD nerves contain fewer C fibers, some of which are not fully ensheathed by the corresponding Schwann cell. Increased blood–nerve barrier permeability and expression of myelin basic protein are noted in SCD tissue. Conclusions: These data are the first to characterize Berkeley SCD mice as a naturally occurring model of peripheral neuropathy. Widespread myelin instability is observed in nerves from SCD mice. This pathology may be explained by increased permeability of the blood–nerve barrier and, thus, increased access to circulating demyelinating agents at the level of primary sensory afferents. Corresponding author. Address: Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, 8701 Watertown Plank Rd, Milwaukee, WI 53226. Tel.: 414-955-8373. E-mail address: cstucky@mcw.edu (C. Stucky). Sponsorships or competing interests that may be relevant to content are disclosed at the end of this article. Received April 06, 2019 Received in revised form May 02, 2019 Accepted May 19, 2019 This is an open access article distributed under the Creative Commons Attribution License 4.0 (CCBY), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2019 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of The International Association for the Study of Pain.

The experiences and needs of people seeking primary care for low-back pain in Australia Introduction: There is a knowledge gap about the current experiences and needs of people with low back pain (LBP) seeking primary care in Australia. Objectives: The aim of this study was to understand the experiences and needs of Australians who have received treatment for LBP in primary care. Methods: This was a prospective, cross-sectional internet survey conducted between July 2017 and September 2017. Participants were adults who had experienced an episode of LBP in the past year, had sought primary care in Australia, and were proficient in English. Outcomes were patient-reported experiences about primary care treatment, including reasons for seeking care, health care practitioners consulted, components of care received, and patients' evaluations of the importance and helpfulness of treatment. Results: A total of 426 Australians completed the survey. The response rate of survey completion was 50%. Participants reported seeking primary care for LBP not only for pain relief, but for difficulties with activities and participation with usual social roles as well as quality of life and mood. Participants consulted multiple health care practitioners and used numerous treatment modalities. Only half reported they received education and a very low proportion were aware of receiving guideline-based advice. The level of satisfaction with care was below moderate for 42% of respondents. Participants reported that they want LBP care to be more person-centred and better tailored to their needs; they also reported wanting more education, particularly about prevention of future episodes and self-management. Conclusions: The needs of people currently seeking primary care for LBP in Australia do not seem to be adequately met. Improving patients' experiences and outcomes may require better integration of health care across providers and delivery of more person-centred care. Corresponding author. Address: Department of Health Professions, Faculty of Medicine and Health Sciences, Macquarie University, Room G813, 75 Talavera Road, NSW 2109, Australia. Tel.: +61 2 9850 6621. E-mail address: Julia.hush@mq.edu.au (J.M. Hush). Sponsorships or competing interests that may be relevant to content are disclosed at the end of this article. Supplemental digital content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal's Web site (www.painrpts.com). Received March 09, 2019 Received in revised form April 15, 2019 Accepted April 20, 2019 This is an open access article distributed under the Creative Commons Attribution-NoDerivatives License 4.0 (CC BY-ND) which allows for redistribution, commercial and non-commercial, as long as it is passed along unchanged and in whole, with credit to the author. © 2019 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of The International Association for the Study of Pain.

Truncal blocks and teenager postoperative pain perception after laparoscopic surgical procedures Introduction: The prevalence of moderate to severe pain is high in hospitalized teenage patients admitted to surgical services. Objectives: The aims of this study were to determine (1) the preoperative and postoperative factors influencing teenager postoperative pain perception; and (2) suffering, defined as the patient's anxiety, pain catastrophizing thoughts, and mood. Methods: Data were collected from medical records and from 2 medical interviews at the time of enrollment and postoperative day 1. Stepwise linear regression was conducted to assess variables that predicted teenagers' pain scores and suffering. Results: Two hundred two patients (mean age = 13.8 years, SD = 1.9), 56.4% females, scheduled for laparoscopic surgical procedures completed the study. The variables found to be significant predictors of pain response in teenagers were pain on the day of surgery (6.81, 95% confidence interval [CI] = 0.08–13.55, P = 0.05) and use of regional anesthesia (single-injection rectus sheath, transversus abdominis plane, and paravertebral nerve blocks) (−6.58, 95% CI = −12.87 to −0.30, P = 0.04). The use of regional anesthesia was found to predict mood responses (all patients: 2.60, 95% CI = 0.68–4.52, P = 0.01; girls: 3.45, 95% CI = 0.96–5.93, P = 0.01; 14–17-year-old teens: 2.77, 95% CI = 0.44–5.10, P = 0.02) and to negatively predict catastrophic thoughts among all patients as a group (−4.35, 95% CI = −7.51 to −1.19, P = 0.01) and among 14- to 17-year-old teens (−5.17, 95% CI = −9.44 to −0.90, P = 0.02). Conclusion: A comprehensive pain approach that includes truncal blocks may improve teenagers' postoperative pain control after laparoscopic surgeries. Corresponding author. Address: Department of Pediatric Anesthesiology, UPMC Children's Hospital of Pittsburgh, Children's Hospital Dr, 4401, Penn Ave, Pittsburgh, PA 15224. Tel.: 412- 692-5260; fax: 421 692 8658. E-mail address: visoium@upmc.edu (M. Visoiu). Sponsorships or competing interests that may be relevant to content are disclosed at the end of this article. Received November 21, 2018 Received in revised form April 18, 2019 Accepted May 15, 2019 This is an open access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives License 4.0 (CCBY-NC-ND), where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially without permission from the journal. http://creativecommons.org/licenses/by-nc-nd/4.0 © 2019 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of The International Association for the Study of Pain.