Research and Education Highlights

A multidisciplinary approach to the care of chronic postsurgical pain: a case report by the Transitional Pain Service

Posted on 16-05-2017 — The serious risks of opioid use (including side effects, dependence, tolerance, and overdose mortality) have raised concerns about safe opioid prescribing and management. Opioid-dependent chronic pain patients who undergo major surgery are especially vulnerable. The current postsurgical care provides little guidance and education for patients to manage their pain. The Toronto General Hospital Transitional Pain Service (TPS) is a novel team that provides specialized, multidisciplinary care for chronic postsurgical pain patients. In a recent case report, UTCSP members Dr. Hance Clarke, Dr. Joel Katz, and colleagues describe the postsurgical care by the TPS team of a patient with complex chronic pain and high opioid dependence.

Reflecting on the 2017 UTCSP Annual Scientific Meeting

Posted on 14-03-2017 — On February 28th, the UTCSP held its Annual Scientific Meeting at the Toronto Rehabilitation Institute. After a welcome and introduction by Drs. Hance Clarke, Rob Bonin, and Bonnie Stevens, attendees had the opportunity to hear from several speakers, including UTCSP faculty and trainees with expertise in both basic and clinical pain research.

Structural neuroimaging reveals the peripheral and central contributions to trigeminal neuralgia pain

Posted on 14-03-2017 — Trigeminal neuralgia (TN) is a chronic neuropathic facial pain disorder, considered as one of the most painful conditions known to medicine. The characteristic feature of TN involves severe episodes of electric shock-like unilateral facial pain. Since a viable animal model of TN has not been established, the etiology and pathophysiological mechanisms of TN remains elusive. In a recent review article, UTCSP members Drs. Danielle DeSouza, Mojgan Hodaie, and Karen Davis discuss their body of work on how structural magnetic resonance imaging (MRI), including diffusion tensor imaging (DTI), can reveal peripheral and CNS abnormalities of TN.

A microglial pannexin-1 mechanism is critical for morphine withdrawal

Posted on 14-03-2017 — Morphine is the gold standard medication for pain management due to its potent analgesic properties. Unfortunately, morphine is also associated severe withdrawal symptoms including nausea, chills, and severe headaches. These symptoms often negatively impact a patient’s attempts to stop opiate-based therapies. As a result, there is significant interest in trying to alleviate negative side effects without attenuation of morphine’s analgesic effect. However, the current understanding of the mechanisms underlying withdrawal is limited.

Opioids, musculoskeletal disorders, and work-related outcomes

Posted on 23-01-2017 — Musculoskeletal disorders (MSDs) such as strains, sprains, fractures, and arthritis are a common cause of work disability and absenteeism. Current guidelines suggest that opioid medications should be prescribed for MSDs only when pain is severe and unresponsive to non-opioid analgesics. However, in some cases best practice guidelines are not being followed and opioids are overprescribed for MSDs, potentially contributing to work disability. 

A sweet solution for reducing procedural pain in neonates

Posted on 23-01-2017 — Sweet solutions have been repeatedly demonstrated to be analgesic in neonates undergoing medical procedures. Despite the extent of evidence for the efficacy of this intervention, clinical trials continue to be conducted using placebo/no-treatment groups. Thus, Dr. Bonnie Stevens and colleagues conducted a cumulative meta-analyses (CMAs) on the impact of sugar solutions on behavioural pain outcomes.

Diurnal variations in chronic pain are mediated by glucocorticoid regulation of ATP

Posted on 09-11-2016 — Diurnal variations in symptoms of chronic pain patients have been widely reported. However, the underlying mechanisms for this phenonemon have yet to be delineated. UTCSP scientist Michael Salter has collaborated with scientists in Japan to help reveal the molecular mechanisms underlying diurnal variations in pain hypersensitivity.

Targeting adenylyl cyclase in bone cancer pain

Posted on 09-11-2016 — Scientists in China have collaborated with UTCSP scientist Min Zhuo to investigate the potential mechanisms of bone cancer pain, a greatly understudied form of chronic pain. Patients with bone cancer experience severe pain at the site of the cancerous tumour, manifesting as continuous and/or spontaneous pain, and allodynia. This pain often becomes worse as the cancer progresses, greatly decreasing patient quality of life. Previous studies of other types of chronic pain have shown a role of the anterior cingulate cortex (ACC) and a compound called adenylyl cyclase (AC) in the development of the chronic pain condition. AC is activated when a neuron is very active, which triggers the production of cAMP and PKA, two second messengers involved in increased gene transcription and translation. This process works to increase glutamate receptor expression at the post-synaptic membrane, effectively potentiating synapses and increasing the fidelity of pain signals reaching the brain. In this study, the authors sought to determine whether this AC cascade in the ACC is also occurring in bone cancer pain models.

Variability in fMRI BOLD signal is a novel indicator of pain sensitivity and coping

Posted on 28-09-2016 — Dr. Karen Davis and PhD student Anton Rogachov have recently discovered that regional blood oxygen level-dependent (BOLD) signal variability is a novel indicator of pain sensitivity and coping. Published online by PAIN in July, this study is the first to demonstrate a link between neural signal variability and an individual’s acute pain sensitivity and ability to cope with pain.

Connaught Summer Institute in Pain keynote lecture: Inhibition of tetrahydrobiopterin synthesis alleviates neuropathic and inflammatory pain

Posted on 28-09-2016 — The Connaught Summer Institute in Pain brought pain research trainees from across the globe to Toronto to learn about the integration of research and clinical practice. The weeklong pain school culminated in a scientific meeting with keynote speaker Dr. Clifford Woolf, a renowned preclinical pain researcher based out of Boston Children's Hospital and Harvard University. Dr. Woolf discussed his recent research published in Neuron which highlighted the potential viability of targeting the tetrahydrobiopterin (BH4) synthesis pathway to treat inflammatory and neuropathic pain in humans.

Cognitive Behavioural Training for Pain: Does it Change your Brain?

Posted on 06-05-2016 — UTCSP member Dr. Karen Davis and her colleagues, Drs. Aaron Kucyi and Tim Salomons, recently reported in PAIN on differences in the brain function of healthy individuals via fMRI before and after cognitive behavioural training and repeated painful heat stimulus application.

Poor Pain Outcomes After Musculoskeletal Surgery Can Be Predicted By Post-Injury Anxiety and PTSD

Posted on 06-05-2016 — New clinical research from UTCSP members Dr. Colin McCartney and Dr. Joel Katz, and PhD candidate Brittany Rosenbloom helps to shed light on the vulnerabilities in patients that may predispose them to have poor pain outcomes, including development of chronic neuropathic pain.

The Periaqueductal Gray Matter: Sub-regions and Functional Connectivity with Descending Pain Modulation Circuitry

Posted on 16-03-2016 — The experience of pain is highly variable between individuals for a multitude of physiological and psychological reasons. Evidence now suggests that part of this variability is due to interactions between ascending nociceptive signaling pathways and descending modulatory circuitry. The periaqueductal gray matter (PAG) is a critical brain region involved in top-down modulatory circuits. The laboratory of Dr. Karen Davis, and post-doctoral fellow Dr. Marie-Andree Colulombe recently investigated sub-regions of the PAG and their functional connectivity with other brain regions involved in pain processing.

Neural Mechanisms Underlying Anxiety-Chronic Pain Interactions

Posted on 16-03-2016 — In a recent article in Trends in Neuroscience, Dr. Min Zhuo discusses the link between anxiety and chronic pain. While chronic pain and anxiety are often comorbid, and treating anxiety can result in a reduction in pain, these conditions are usually studied separately. Dr. Zhuo proposes that these conditions are related via long-term potentiation (LTP) mechanisms in the anterior cingulate cortex (ACC).

Abnormal cross-network functional connectivity in chronic pain and its association with clinical symptoms

Posted on 20-01-2016 — Kasey Hemington, Keith Wu, Aaron Kucyi, Robert Inman and Karen Davis recently published a neuroimaging study, characterizing abnormalities between functional brain networks in chronic pain patients. The authors used resting state, functional magnetic resonance imaging to uncover abnormal connections between functional networks that were closely related to clinical symptom severity.

Longitudinal Study of Catastrophizing, Pain and Cortical Thickness in Chronic Pain Patients

Posted on 20-01-2016 — Neuropathic pain is a common chronic pain condition, which occurs following peripheral nerve injury (PNI). It is currently unknown why only some individuals with PNI develop chronic pain. However, it is predicted that both biological and psychological factors contribute to this process. The laboratory of Dr. Karen Davis recently conducted a longitudinal investigation of pan catastrophizing (i.e., when an individual has exaggerated negative thinking about painful experiences) and insula gray matter changes in patients with nerve injury.

Preventing chronic post-surgical pain through the Toronto General Hospital Transitional Pain Service

Posted on 23-11-2015 — Chronic postsurgical pain can develop in 5-10% of patients within a year of surgery. Chronic post-surgical pain is difficult to treat, and results in poor patient outcomes, including loss of work, increased medical leave, and loss of quality of life. The global annual cost of chronic post-surgical pain has been estimated in the billions of dollars, underscoring the need for better treatment for post-surgical pain.

Efficacy of celecoxib in the treatment of chronic nonspecific low back pain

Posted on 19-11-2015 — Dr. Robert D. Inman’s research group has demonstrated that celecoxib, a non-steroidal anti-inflammatory drug, which selectively inhibits COX-2, has superior efficacy as compared to acetaminophen in treating chronic nonspecific low back pain. Dr. Inman conducted a randomized controlled trial to compare the effects of a 4-week treatment of either celecoxib (200mg, 2x daily) or acetaminophen (500mg, 2x daily) on both pain scores and MRI scores in 50 patients with nonspecific low back pain. Patients receiving celecoxib had more relief of total back pain and nocturnal back pain as well as more significant improvements on disability measures and global assessment measures than patients receiving acetaminophen. Neither celecoxib nor acetaminophen treatment produced any changes on MRI scores of inflammatory lesions nor morning stiffness, suggesting that both treatments are only effective at reducing pain scores.

A New Method to Detect Dishonesty in Self-Report Measures of Pain

Posted on 18-09-2015 — Self-report is the most valid and frequently used measure of pain in both clinical and research settings. However, some individuals may be inclined to provide deceitful self-reports in certain situations (e.g. insurance fraud). Thus, it is desirable to have a reliable method to detect dishonesty in self-report. Recently, UTCSP alumni Dr. Aaron Kucyi demonstrated that the use of sensory interference during self-report may be a potential tool to identify feigned self-reports.

Different Mechanisms of Spinal Cord Neuron Disinhibition in Neuropathic Pain Models Require Different Therapeutic Interventions

Posted on 18-09-2015 — Exciting new research from Dr. Steven Prescott’s lab is working to bridge the gap between basic research on neuropathic pain etiology to possible clinical interventions to treat neuropathic pain. Dr. Steven Prescott is a UTCSP member and scientist at the Hospital for Sick Children. In this paper, lead author Dr. Kwan Lee uses a unique method to measure intact spinal cord neurons from alive, anaesthetized animals, overcoming disadvantages of ex-vivo methodologies.