Background Many medically-refractory trigeminal neuralgia patients are non-responders to surgical treatment. Few studies have explored how trigeminal nerve characteristics relate to surgical outcome, and none have investigated the relationship between subcortical brain structure and treatment outcomes. Methods We retrospectively studied trigeminal neuralgia patients undergoing surgical treatment with microvascular decompression. Preoperative magnetic resonance imaging was used for manual tracing of trigeminal nerves and automated segmentation of hippocampus, amygdala, and thalamus. Nerve and subcortical structure volumes were compared between responders and non-responders and assessed for ability to predict postoperative pain outcome. Results In all, 359 trigeminal neuralgia patients treated surgically from 2005–2018 were identified. A total of 34 patients met the inclusion criteria (32 with classic and two with idiopathic trigeminal neuralgia). Across all patients, thalamus volume was reduced ipsilateral compared to contralateral to the side of pain. Between responders and non-responders, non-responders exhibited larger contralateral trigeminal nerve volume, and larger ipsilateral and contralateral hippocampus volume. Through receiver-operator characteristic curve analyses, contralateral hippocampus volume correctly classified treatment outcome in 82% of cases (91% sensitive, 78% specific, p = 0.008), and contralateral nerve volume correctly classified 81% of cases (91% sensitive, 75% specific, p < 0.001). Binomial logistic regression analysis showed that contralateral hippocampus and contralateral nerve volumes together classified outcome with 84% accuracy (Nagelkerke R2 = 65.1). Conclusion Preoperative hippocampal and trigeminal nerve volume, measured on standard clinical magnetic resonance images, may predict early non-response to surgical treatment for trigeminal neuralgia. Treatment resistance in medically refractory trigeminal neuralgia may depend on the structural features of both the trigeminal nerve and structures involved in limbic components of chronic pain.

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Introduction: This needs assessment evaluated residents’ and medical students’ knowledge of Competence by Design (CBD), perceived benefits of and challenges or barriers to the transition to CBD for residents, and perceived overall preparedness for the transition to CBD in diagnostic radiology. Materials and Methods: All diagnostic radiology residents and medical students in Canada were eligible to participate in this national cross-sectional, questionnaire-based needs assessment. Knowledge of CBD was evaluated through participants’ self-reported rating of their knowledge of CBD on a 5-point Likert scale. Perceived benefits of and challenges or barriers to the transition to CBD for residents were rank ordered. Participants’ overall self-reported preparedness for the transition to CBD was assessed on a 5-point Likert scale. Data were summarized by descriptive statistics and bivariate analyses were conducted as appropriate. Results: Ninety-four residents ( n = 77) and medical students ( n = 17) participated in this needs assessment. Participants’ mean ± standard deviation self-reported rating of their overall knowledge of CBD was 2.86 ± .94. Provision of meaningful feedback to learners and learners’ ability to identify their own educational needs were among the highest ranked perceived benefits of the transition to CBD, while demands on time and increased frequency of evaluation were among the highest ranked perceived challenges or barriers to the transition to CBD. Few participants reported being either “prepared” (4.7%) or “somewhat prepared” (14.0%) for the transition to CBD. Conclusion: Preparedness for the transition to CBD in diagnostic radiology may be improved. Targeted interventions to augment the preparedness of residents and medical students should be considered.

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