The Spatial Extent of Pain Is Associated with Pain Intensity, Catastrophizing and Some Measures of Central Sensitization in People with Frozen Shoulder

The aim of this cross-sectional study was to explore the spatial extent of pain and its association with clinical symptoms, psychological features, and pain sensitization in people with frozen shoulder (FS). Forty-eight individuals with FS completed pain drawings (PDs) and reported their clinical symptoms including pain intensity (Visual Analogue Scale) and shoulder disability (Shoulder Pain and Disability Index). Moreover, pain sensitization measurements (pressure pain thresholds, temporal summation, conditioned pain modulation, and Central Sensitization Inventory (CSI)) were assessed. Psychological features were assessed by Pain Catastrophizing Scale (PCS) and Pain Vigilance and Awareness Questionnaire. Pain frequency maps were generated, Margolis rating scale was used for pain location, and Spearman correlation coefficients were computed. The mean (SD) pain extent was 12.5% (6.7%) and the most common painful area was the anterolateral shoulder region (100%). Women presented a more widespread pain distribution compared with men. Significant positive associations were obtained between pain extent and current pain intensity (rs = 0.421, p < 0.01), PCS (rs = 0.307, p < 0.05) and CSI (rs = 0.358, p < 0.05). The anterolateral region of the shoulder was the most common painful area in people with FS. Women with FS presented more extended areas of pain; and a more widespread distribution of pain was correlated with higher levels of pain, pain catastrophizing and pain sensitization.

Psychophysical testing in chronic migraine and chronic tension type headache: An observational study

Background Clinical presentation is the key to the diagnosis of patients with migraine and tension-type headache, but features may overlap when both become chronic. Psychophysical parameters may distinguish both conditions. We aimed to compare psychophysical aspects of patients with chronic migraine, chronic tension-type headache and headache-free controls, and to determine whether these can predict headache frequency. Methods An examiner blinded to the diagnosis assessed 100 participants (chronic migraine (n = 38), chronic tension-type headache (n = 31) and controls (n = 31)). Assessed variables included painful area, pressure pain thresholds, temporal summation, cervical range of motion, neck posture, headache and neck impact, quality of life, and kinesiophobia. Comparison between groups was performed with one-way ANOVA and multiple linear regression was used to assess the headache frequency predictors. Results We found differences of both headache groups compared to controls ( p < 0.01), but not between headache groups. Neck disability was a significant predictor of headache frequency for chronic tension-type headache (adjusted R2 = 0.14; β = 0.43; p = 0.03) and chronic migraine (adjusted R2 = 0.18; β = 0.51; p < 0.01). Conclusions Chronic tension-type headache and chronic migraine showed similar psychophysical results, but were significantly worse when compared to controls. The psychophysical examination did not discriminate between headache types. The variable best explaining headache frequency for both headache types was neck disability.

Development of the Bristol Rabbit Pain Scale (BRPS): A multidimensional composite pain scale specific to rabbits (Oryctolagus cuniculus)

A species-specific composite pain scale is a prerequisite for adequate pain assessment. The aim of this study was to develop a multidimensional pain scale specific to rabbits (Oryctolagus cuniculus) called the Bristol Rabbit Pain Scale (BRPS). The scale was developed over five phases using a unique combination of methods: focus groups and behavioural observation. The first two phases aimed at identifying descriptors to describe a rabbit in pain, and then reducing their number, both using focus groups. A total of 72 pain descriptors were grouped under six categories (Demeanour, Posture, Facial expression, Attention to the painful area, Audible and Other) and ‘No pain’ descriptors were added. The third phase aimed to confirm, through video observation of rabbits, the categories and descriptors previously described, to reject those terms that were ambiguous, and identify any new descriptors that had not been included in the previous list of descriptors. This led to the rejection of the categories Audible and Attention to the painful area and of 34 descriptors. Seven new descriptors were identified. The last two phases constructed the final format of the BRPS by refining the categories, ranking the descriptors on an ordinal scale and testing the internal reliability of the scale using Cronbach’s alpha test. This led to a composite pain scale of six categories (Demeanour, Posture, Locomotion, Ears, Eyes and Grooming) with four intensities of pain (0, 1, 2, and 3), a total score of 0–18, and a high Cronbach’s alpha coefficient (alpha = 0.843). This BRPS fills an important gap in the field of rabbit medicine and has the potential to improve the assessment and management of pain in rabbits providing veterinary professionals with a novel multidimensional pain assessment tool. Further studies will investigate the clinical utility, validity and reliability of the BRPS.

8% Capsaicin Patch in Treatment of Peripheral Neuropathic Pain

Background: Neuropathic pain is a complex condition that is difficult to control and has a high impact on quality of life. 8% Capsaicin patch can be a therapeutic strategy in the treatment of peripheral neuropathic pain. Objectives: This study aims to (1) evaluate clinical efficacy and (2) tolerability of 8% capsaicin patch in a Pain Unit. Study Design: Retrospective observational study Setting: Portuguese Pain Unit Methods: A sample of 120 patients diagnosed with peripheral neuropathic pain, underwent treatment with the 8% capsaicin patch between February 2011 and February 2019 in a Portuguese Pain Unit. Patients were included in one of the following groups according to the etiology of pain: postherpetic neuralgia (PHN), chronic post-surgical pain (CPSP), post traumatic neuropathic pain (PTNP), diabetic neuropathy (DN), regional pain syndrome. complex I and II (CRPS I / II), HIVassociated neuropathy (HIVN), lumbar neuropathic pain (LNP), trigeminal neuralgia (TN) and other neuropathies (O). The evaluated parameters were: pain intensity according to unit protocol (numerical rating scale), pain characteristics, location, size of the painful area. The evolution of pain intensity after treatment (patients were considered as responders to therapy if the decrease in NRS was equal to or greater than 30%; patients with a decrease in NRS of 50% or more were also analyzed), the area of pain and the need for adjuvant analgesic therapy, as well as the tolerability to treatment and the identification of eventual predictors of its efficacy were evaluated, at 15 days, 8 weeks and 12 weeks after 8% capsaicin patch. Results: Of the 120 patients in the sample, 40.8% had a ≥ 30% decrease in basal pain intensity 15 days after treatment, 43.3% after 8 weeks and 45.0% after 12 weeks. 30.8% of patients had ≥ 50% decreased basal pain intensity 15 days after treatment, 27.5% after 8 weeks and 30.0% after 12 weeks. Pain area decreased in 36.7% of patients and 18.3% reduced chronic analgesic therapy within 12 weeks after 8% capsaicin patch application. There was only one case of intolerance to the treatment. Limitations: This study has the limitations inherent to a retrospective study. The study period was only 12 weeks and some diagnostic groups included a small number of patients. Conclusion: Treatment of peripheral neuropathic pain with 8% capsaicin patch seem to be effective in the short and medium term, both in decreasing pain intensity and in reducing the painful area. Its application is tolerated by most patients. Key words: 8% capsaicin patch, peripheral neuropathic pain, pain intensity, painful area

Effect of Low Dose Lignocaine Injection in the Treatment of Post Stroke Pain: A Case Report

Pain experienced after a stroke is one of the worst experience for a given patient. Post stroke pain can present in various forms of which central post stroke pain (CPSP) is a neuropathic pain involving the area affected during the stroke. Till date there were different classes of medication used to treat CPSP without any promising results. This indirectly indicates so many mechanisms were included in these patients resulting in pain. We would like report a case of CPSP successfully treated in our institute with low dose lignocaine injection peripherally. We would like to conclude that the afferent sensory input from the painful area plays a role in maintaining the spontaneous (and the evoked) pain in CPSP which are getting blocked by giving low dose lignocaine injection peripherally. Further studies will be required to establish this novel treatment.

Comparing Intradermal Sterile Water with Intravenous Morphine in Reducing Pain in Patients with Renal Colic: A Double-Blind Randomized Clinical Trial

Objective: The present study was conducted to investigate the effect of intradermal administration of sterile water compared to intravenous morphine on patients with renal colic. Methods: This double-blind, randomized clinical trial study was conducted in 2017 to compare the therapeutic effects of intradermal sterile water with those of intravenous morphine on patients with renal colic presenting to the emergency departments (ED) of Imam Khomeini and Golestan Hospitals in Ahvaz, Iran. The first group received 0.5 ml of intradermal sterile water, and the second group 0.1mg/kg of intravenous morphine plus 0.5 ml of intradermal sterile water in the most painful area or the center of the painful area in the flank. The pain severity was measured using a visual analogue scale (VAS), and the medication side-effects were recorded at the beginning of the study and minutes 15, 30,45 and 60. Result: A total of 94 patients were studied in two groups. The mean severity of pain was 2.97 ± 1.51 in the sterile water group and 2.34 ± 1.89 in the morphine group at minute 30 (P=0.042), 2.58 ± 1.43 in the sterile water group and 1 ± 1.23 in the morphine group at minute 45 (p<0.001), and 1.89 ± 1.7 in the sterile water group and 0.52 ± 0.79 in the morphine group at minute 60 (p<0.001). Conclusion: Morphine reduces pain faster and more effectively than intradermal sterile water; nevertheless, treatment with intradermal sterile water can be used as an appropriate surrogate or adjunct therapy for pain control, particularly in special patients or in case of medication scarcity.

Hawley retainer and lichenoid reaction: a rare case report

Background Oral lichenoid reaction (OLR) is a type IV cell-mediated immune response in the oral cavity. There is an established relationship between various dental materials and OLR, but few cases reports reported the occurrence of a lichenoid reaction in association with the use of a Hawley retainer. Case presentation A female patient (twenty years of age) has been complaining of a reddish painful area on the tongue, which started one year ago and has been increasing in size over time. The patient completed orthodontic treatment two years ago and has been using a Hawley retainer for orthodontic retention since then. After performing histological analysis and patch test, the lesion was diagnosed as a lichenoid reaction to the Hawley retainer. Topical corticosteroids were prescribed, and the patient was asked to stop using the retainer and followed for six months. Conclusions It is difficult to diagnose lichenoid lesions and even more challenging to differentiate between OLP and OLR, therefore it is essential to do a full intraoral and extraoral examination. OLL can occur in association with Hawley retainer, which we believe could be because it is made of an acrylic based material. Generally, OLL resolves after removal of the cause.

Sensory mapping of lumbar facet joint pain: a feasibility study

Objective: To evaluate the feasibility of sensory mapping of lumbar facet joint pain in patients scheduled to undergo radiofrequency (RF) denervation. Design: Prospective cohort study. Setting: University teaching hospital. Subjects: A total of 15 participants listed for RF denervation of lumbar facet joint. Method: After written informed consent, participants were recruited to the study. Participants completed a pain diagram prior to their procedure. After successful image-guided placement of RF cannulas, the sensory detection threshold using 50 Hz stimulation was obtained, followed by application of suprathreshold stimulation. Participants mapped their stimulated area in comparison to their pre-procedure pain diagram. Results: All 15 participants had previously undergone diagnostic blocks. All participants were able to report either pain or paraesthesia during suprathreshold stimulation. In total, 14 out of 15 participants reported complete coverage of their usual painful area with suprathreshold stimulation of nerves scheduled for RF denervation. In one of the participants, an area of upper lumbar pain was not covered during suprathreshold stimulation. Nearly two-thirds of the participants (n = 9), reported either pain or paraesthesia, outside their normal painful area during suprathreshold stimulation. A total of 71 nerves were scheduled for RF denervation. Sensory electrical stimulation was successfully achieved in 68 out of 71 nerves (96%). The average sensory detection threshold was found to be 0.3 V while the suprathreshold stimulation was 0.6 V. Conclusion: Lumbar facet joint pain can be mapped using suprathreshold sensory stimulation, which has the potential to introduce objectivity during RF denervation.

Radiofrequency Mapping Prior to Dorsal Root Ganglion Stimulation in a Patient with CRPS and Transitional Vertebral Anatomy: A Case Report

Dorsal root ganglion (DRG) stimulation is an effective treatment for chronic, refractory complex regional pain syndrome (CRPS). Routinely, the placement of a DRG stimulator lead is based on established anatomical knowledge of dermatomes. In patients with lumbosacral transitional vertebral anatomy, dermatome maps are not dependable due to dermatomal variance. This can make correct placement of stimulator leads challenging as the supposed target may not actually be responsible for sensing the painful area. We present a case of a 60-year-old woman with CRPS and lumbarization of the S1 vertebral body (presence of 6 lumbar vertebrae and 4 sacral vertebrae) who failed a DRG stimulator trial after using conventional dermatome maps to identify target DRGs assuming that the nerve exiting below L6 corresponded to the S1 dermatome. Following the failed trial, sensory stimulation of the DRG via radiofrequency stimulation was used to accurately map dermatomes leading to a successful DRG stimulation implant at a DRG level that differed from expected based on traditional dermatome maps. Thus, DRG stimulation may guide decisionmaking in regard to target stimulation in patients with abnormal vertebral anatomy. Key words: Dorsal root ganglion stimulation, dermatome mapping, radiofrequency stimulation, spinal anomaly, lumbosacral transitional vertebrae, complex regional pain syndrome, neuromodulation, dermatomal variance

128 The Importance of Somatotopy to Achieve Clinical Benefit in Motor Cortex Stimulation for Pain Relief

INTRODUCTION The aim of this study was to search the relationship between the anatomical location and the eventual analgesic effect of each contact. METHODS 22 patients (14 men and 8 women) suffering from central and/or peripheral neuropathic pain were implanted with stimulation of the precentral cortex. The implantation of the electrodes was performed using intraoperative: 1) Anatomical identification by Neuronavigation with 3D MRI, 2) Somesthetic evoqued potentials monitoring to check the potential reverse over the central sulcus, 3) Electrical stimulations through the dura to identify the motor responses and its somatotopy. In order to locate postoperatively the electrodes, a 3D-CT was performed in each case and fused with the preoperative MRI. The clinical analgesic effects of cortical stimulation were collected on a regular basis (VAS reduction > 50%, drugs consumption). Data were analyzed to search a correlation between the anatomical position of contacts and analgesic effects. RESULTS >Post implantation analgesic effects were obtained in 18 (81.81%) patients out of 22. The analgesic effect was companied with reduction of the drugs consumption in 15 patients (68.18%). The post-operative 3D CT analysis shows a correspondence between the effective contacts localization and the motor cerebral cortex somatotopy in the patients with post-operative good analgesic effects. No correspondence was found between the contacts localization and the motor cerebral cortex somatotopy in the 4 patients with no analgesic effects. In three out of these four patients, analgesic effects were obtained after a new surgery allowing a replacement of the electrode position over the motor cortex somatotopy corresponding to the painful area. CONCLUSION This study shows the correlation between position of the contact over the precentral cortex and the analgesia obtained when the somatotopy of the stimulated cortex correspond to the painful area.