Jordi Perez

Dietary Omega-3 Fatty Acids May Be Associated with Increased Neuropathic Pain in Nerve-Injured Rats

Certain dietary proteins and oils are capable of decreasing chronic neuropathic pain levels in rats after partial sciatic nerve ligation injury. We tested, for the first time, the role of dietary polyunsaturated fatty acids in suppressing pain in partial sciatic nerve ligation-injured rats. Six groups of male Wistar rats were fed an identical casein-based, fat-free diet for 1 wk preceding partial sciatic nerve ligation injury and for 1 wk thereafter. In addition, rats received, via gavage, 1 mL/day of pure canola, corn, hemp, soy, or sunflower oil, differing significantly in their &ohgr;-3 and &ohgr;-6 polyunsaturated fatty acid content, or 1 mL of plain water. Responses to tactile and noxious heat stimuli were recorded before and after surgery and a difference score was calculated for each group by subtracting the preoperative from the post-partial sciatic nerve ligation values. Heat hyperalgesia, but not tactile allodynia, was significantly different among the dietary groups (P = 0.005). Heat hyperalgesia of rats fed hemp oil, developing the most robust response, was significantly larger compared with rats fed corn oil, developing the least pain model (difference score: 24.3 ± 4.1 s versus 6.1 ± 3.1 s, respectively; P < 0.001). These oils contain similar levels of &ohgr;-6 polyunsaturated fatty acids (hemp, 60%; corn, 58%) but their &ohgr;-3 levels are 28-fold different (20% versus 0.7%, respectively). A significant correlation was found among dietary levels of &ohgr;-3, but not &ohgr;-6 or the &ohgr;-3/&ohgr;-6 ratio, of the six dietary groups and heat hyperalgesia (P = 0.006). We conclude that dietary oil might predict levels of neuropathic pain in rats and that this effect may be associated with dietary &ohgr;-3 levels.

Interventional Analgesic Management of Lung Cancer Pain

Lung cancer is one of the four most prevalent cancers worldwide. Comprehensive patient care includes not only adherence to clinical guidelines to control and when possible cure the disease but also appropriate symptom control. Pain is one of the most prevalent symptoms in patients diagnosed with lung cancer; it can arise from local invasion of chest structures or metastatic disease invading bones, nerves, or other anatomical structures potentially painful. Pain can also be a consequence of therapeutic approaches like surgery, chemotherapy, or radiotherapy. Conventional medical management of cancer pain includes prescription of opioids and coadjuvants at doses sufficient to control the symptoms without causing severe drug effects. When an adequate pharmacological medical management fails to provide satisfactory analgesia or when it causes limiting side effects, interventional cancer pain techniques may be considered. Interventional pain management is devoted to the use of invasive techniques such as joint injections, nerve blocks and/or neurolysis, neuromodulation, and cement augmentation techniques to provide diagnosis and treatment of pain syndromes resistant to conventional medical management. Advantages of interventional approaches include better analgesic outcomes without experiencing drug-related side effects and potential for opioid reduction thus avoiding central side effects. This review will describe various pain syndromes frequently described in lung cancer patients and those interventional techniques potentially indicated for those cases.

Ultrasound-Guided Cervical Medial Branch Radiofrequency Neurotomy: Can Multitined Deployment Cannulae Be the Solution?

Background and Objectives Novel multitined cannulae constitute an attractive option for ultrasound-guided radiofrequency neurotomy of cervical medial branches. The deployment tines increase the cannulas active area, thus altering its lesion size. Despite their theoretical benefits, multitined cannulae have not been assessed. In this bench study, we sought to investigate the lesions produced by a standard 18-gauge and 2 commercially available multitined deployment cannulae. We created ex vivo models to evaluate lesion morphology at a periosteal interface using approach angles likely to be encountered during an ultrasound-guided technique. Methods Two ex vivo models were assembled using chicken breast tissue and bovine tibia. Monopolar lesions were carried out with 3 commercially available cannulae (18-gauge curved [S], 17-gauge with laterally deploying tines [N], and 18-gauge with distally deploying tines [T]). All cannulae were positioned at 0, 25, 45, and 90 degrees to the periosteal plane. For each angulation and cannula, 2 series of measurements were recorded to document lesion morphology in the axial and sagittal planes. Data collected included the lesions surface area, shape, and dimensions relative to the needle tip. Results A total of 240 lesions were analyzed. The performances of S and N cannulae were significantly affected by approach angle, with lesion size decreasing as the angle increased. In contrast, T cannulae displayed similar lesion surface areas at 0 and 90 degrees. The multitined N and T cannulae produced the largest lesions at 0/25 and 90 degrees, respectively. Lesion height varied inversely according to approach angle for S and N cannulae, whereas T cannulae displayed stable characteristics. Conclusions Unlike their S and N counterparts, T cannulae demonstrated stable lesion characteristics at varying approach angles.

New frontier: cancer pain management clinical fellowship

Cancer pain is a multi-dimensional experience, varies from person to person both physically and psycho-socially, and impacts all aspects of the patients’ quality of life. Majority of patients with an advanced or metastatic cancer will experience pain. It is estimated that as many as half of cancer patients are under-treated and as many as 20% experience pain refractory to the conventional WHO ladder of pain management. The McGill University Health Centre (MUHC) Cancer Pain Clinic (CPC) was created to meet the needs of those patients with a diagnosis of cancer whose pain had become a main symptom and those who failed to respond to conventional treatment. The clinic offers a unique interdisciplinary approach with a core team that includes an anesthesiologist, a palliative care physician, a radiation oncologist, a nurse clinician specialist in oncology and palliative care, and, recently, also an interventional radiologist. A cancer pain clinical fellowship was offered for the first time in July 2016. It provides intense training in the classification, epidemiology, pathophysiology, and treatment of cancer pain. Through our education program, the fellow learns to appreciate, weigh, and respond to the full spectrum of factors influencing a specific patient’s condition and to develop a tailor-made care plan. To our knowledge, it is the only fellowship program in existence that focuses exclusively on cancer pain. We see it as a beacon and hope that our graduate fellows become professional leaders with a quest not only to provide the best possible care but also to raise awareness of the humanitarian need to control cancer pain.

An internet based survey to assess clinicians' knowledge and attitudes towards opioid induced hypogonadism.

Long‐term opioid therapy for chronic pain management requires regularly assessing and documenting benefits and side effects. Opioid‐induced sex hormone disturbances are a complication that needs to be assessed routinely and perhaps not only when suspected. There is abundant literature about its prevalence, clinical consequences, and treatment, yet routine hormone screening and appropriate treatment are seldom performed in pain clinics. Ignorance, skepticism, and/or indifference are possible reasons explaining why opioid‐induced hypogonadism (OIH) remains underdiagnosed among chronic pain patients.

The McGill University Health Centre interdisciplinary approach to cancer pain management: Description of treatments and outcomes.

190 Background: Cancer-related symptom management is best achieved by interdisciplinary teams. In 2011, the MUHC launched an interdisciplinary Cancer Pain Clinic including palliative care, anesthesia, radiation oncology and nursing with rapid access to physiotherapy, occupational therapy and psychosocial oncology. METHODS We retrospectively analysed all new outpatients completing two subsequent visits since March 2013. Variables included a) symptom severity with the Edmonton Symptom Assessment Scale (ESAS), b) pain with the Brief Pain Inventory (BPI) and c) treatment including medication (type, formulation, dose of opioids) of non-pharmacological approaches. RESULTS 71 patients were analysed. Symptom management: Severity of pain and other five symptoms decreased significantly at V2 or V3 (Table). Pain significantly decreased in all four BPI categories. One third of patients had ≥50% pain relief at V2 or V3. Number of severe pain cases decreased (45% at V1 to 18% at V3) in parallel to an increase of mild pain cases (11% at V1, 41% at V3). TREATMENTS Acetaminophen, anticonvulsants and NSAIDs were the most common non-opioid drugs. Opioid prescription remained constant at an 80% yet the ratio between short acting (SA) and long acting (LA) changed at V3 compared to V1 (V1: SA/LA=76/44; V3: SA/LA=48/58) and the morphine equivalent daily doses decreased (V1: 100±194 mg, V2: 84±158mg and V3: 65±80mg). Among non-pharmacological methods, 28% of patients received interventional procedures, 18% psychotherapy and 12% palliative radiotherapy. CONCLUSIONS We believe that the pain and other symptom improvement observed after three visits along with a lower opioid consumption is a result of the interdisciplinary approach offered. [Table: see text].