Accepted

Chronic pain is a complex multidimensional condition that requires management with multiple professions' expertise. Healthcare training programs tend to adhere to curricula within their own profession with very few interactions with other groups. Project ECHO (Extension for Community Healthcare Outcomes) Chronic Pain and Opioid Stewardship is a model for interprofessional education, using tele-mentoring, case-base discussions and clinically focused presentations. The goal is to improve competency and confidence in managing complex cases in primary care. This qualitative study engaged twenty healthcare practitioners from multiple professions who had participated in ECHO in focus group discussions about managing patients with chronic pain, about their reasons for and the effect of participating in Project ECHO Ontario Chronic Pain/Opioid Stewardship, and about their perspectives on interprofessional care. The results show that participating in ECHO resulted in personal and professional benefit, and increased understanding about their own roles and limitations, as well as other healthcare professionals' roles. The participants described changes in their attitudes toward patients with chronic pain, and their colleagues from other professions. Non-physician participants were more likely to approach physicians to discuss their assessment and diagnosis as well as prescriptions. The interprofessional nature of the program was seen as positive and contributed to perceived changes in practice collaboration. These results show that healthcare professionals from multiple professions expressed mainly positive views of ECHO's emphasis on interprofessional care, with different professions appreciating different aspects of that approach.

Some forms of chronic pain are thought to be driven and maintained by nociceptive input, which can drive plasticity within nociceptive pathways. We have previously identified abnormalities along the entire nociceptive pathway in chronic myalgic temporomandibular disorders (mTMD), including the trigeminal nerves, brainstem pathways, and in the thalamus and somatosensory cortex. These data suggest that there is a peripheral nociceptive drive in mTMD, but the source of this nociceptive activity remains unknown. Here, our aim was to determine whether structural abnormalities exist in the muscles of mastication of patients with chronic mTMD. Specifically, we tested whether the volume of the temporalis muscle and its tendon-aponeurosis-complex (TAC, a structure that dissipates forces in a muscle) in mTMD patients differ compared to age- and sex-matched controls. To do so, we segmented these structures on T1-weighted structural MR images. We found that muscle volumes in mTMD were not different to controls. However, the mTMD group had significantly smaller volumes of the bilateral temporalis TAC, and thus a smaller TAC-to-muscle volume ratio. These findings were consistent across 2 independent cohorts of 17 mTMD patients, compared to 17 age- and sex-matched controls. We propose a model where reduced TAC-to-muscle ratio could result in a predisposition to muscle tissue injury. In sum, abnormalities of the temporalis muscles in mTMD supports our hypothesis that chronic mTMD pathophysiology may be related to peripheral nociceptive barrage originating from the muscles of mastication.