Background: Abuse of prescription opioids is a serious problem in North America. Aims: The aim of this study was to conduct a systematic review of peer-reviewed and grey literature to examine existing strategies aimed at improving the appropriate use of prescription opioids and/or reducing the misuse, abuse, and diversion of these drugs. Methods: The following electronic databases were searched to September 2015 without language restrictions: MEDLINE, EMBASE, PsycINFO, and CINAHL; the grey literature was searched to May 2014. Reference lists of retrieved papers were also searched. Studies were eligible if a strategy was implemented and its impact on at least one of the primary outcomes of interest (appropriate prescription opioid use; misuse, abuse, opioid use disorder, diversion; overdose) was measured. Standardized, prepiloted forms were used for relevance screening, quality appraisal, and data extraction. Results: A total of 65 studies that assessed 66 distinct strategies were identified. Due to the heterogeneity of the strategies, a qualitative synthesis was conducted. Many studies combined more than one type of strategy and measured various types of outcomes. The strategies with most promising results involved education, clinical practices, collaborations, prescription monitoring programs, public campaigns, opioid substitution programs, and naloxone distribution. We also found strategies that had some unintended consequences after implementation. Conclusions: Our review identified successful strategies that have been implemented and evaluated in various jurisdictions. There is a need to replicate and disseminate these strategies where the problem of prescription opioid misuse and abuse has taken a toll on society.

Background: Gamma Knife radiosurgery (GKRS) is a minimally invasive procedure for trigeminal neuralgia secondary to multiple sclerosis (MS-TN). Patients with MS-TN experience suboptimal response rates to treatment, and the relationship between trigeminal microstructure and treatment outcome is poorly understood. Objective: To characterize imaging features of MS-TN pain and GKRS response. Methods: 3 T diffusion-weighted imaging (DWI), T1-w, T2-w, and fluid-attenuated inversion recovery (FLAIR) sequences were acquired for 18 MS-TN patients undergoing GKRS. Brainstem plaques were standardized into a common space to determine plaque distribution. Ratio of T1-w/T2-w or “myelin maps (MM)” was generated. Multi-tensor tractography was used to delineate the radiosurgical target (RT), root entry zone (REZ), and proximal pontine segment (PPS) of the trigeminal nerves. Results: Laterality of MS-TN is associated with increased axial diffusivity at the PPS, whereas decreased MM at the PPS correlated with poor GKRS response. Preoperatively, GKRS responders have higher fractional anisotropy at the RT, higher axial diffusivity at the REZ, and higher MM intensities at the PPS. Conclusion: This study demonstrates that diffusivities and MM intensities are important correlates of pain and treatment response, respectively. Overall, preoperative multimodal assessment of the central trigeminal pathway is a better indicator of GKRS response than postoperative assessment of the reduction in fractional anisotropy peripherally.

Imaging of trigeminal neuralgia (TN) has demonstrated key diffusion tensor imaging-based diffusivity alterations in the trigeminal nerve; however, imaging has primarily focused on the peripheral nerve segment because of previous limitations in reliably segmenting small fiber bundles across multiple subjects. We used Selective Automated Group Integrated Tractography to study 36 subjects with TN (right-sided pain) and 36 sex-matched controls to examine the trigeminal nerve (fifth cranial nerve [CN V]), pontine decussation (TPT), and thalamocortical fibers (S1). Gaussian process classifiers were trained by scrolling a moving window over CN V, TPT, and S1 tractography centroids. Fractional anisotropy (FA), generalized FA, radial diffusivity, axial diffusivity, and mean diffusivity metrics were evaluated for both groups, analyzing TN vs control groups and affected vs unaffected sides. Classifiers that performed at greater-than-or-equal-to 70% accuracy were included. Gaussian process classifier consistently demonstrated bilateral trigeminal changes, differentiating them from controls with an accuracy of 80%. Affected and unaffected sides could be differentiated from each other with 75% accuracy. Bilateral TPT could be distinguished from controls with at least 85% accuracy. TPT left–right classification achieved 98% accuracy. Bilateral S1 could be differentiated from controls, where the affected S1 radial diffusivity classifier achieved 87% accuracy. This is the first TN study that combines group-wise merged tractography, machine learning classification, and analysis of the complete trigeminal pathways from the peripheral fibers to S1 cortex. This analysis demonstrates that TN is characterized by bilateral abnormalities throughout the trigeminal pathway compared with controls and abnormalities between affected and unaffected sides. This full pathway tractography study of TN demonstrates bilateral changes throughout the trigeminal pathway and changes between affected and unaffected sides.