Hooten, W. Michael

Dorsal root ganglia (DRG) are critical anatomical structures involved in nociception. Intraganglionic (IG) drug delivery is therefore an important route of administration for novel analgesic therapies. Although IG injection in large animal models is highly desirable for preclinical biodistribution and toxicology studies of new drugs, no method to deliver pharmaceutical agents into the DRG has been reported in any large species. The present study describes a minimally invasive technique of IG agent delivery in domestic swine, one of the most common large animal models. The technique utilizes CT guidance for DRG targeting and a custom-made injection assembly for convectionenhanced delivery (CED) of therapeutic agents directly into DRG parenchyma. The DRG were initially visualized by CT myelography to determine the optimal access route to the DRG. The subsequent IG injection consisted of 3 steps. First, a commercially available guide needle was advanced to a position dorsolateral to the DRG, and the dural root sleeve was punctured, leaving the guide needle contiguous with, but not penetrating, the DRG. Second, the custom-made stepped stylet was inserted through the guide needle into the DRG parenchyma. Third, the stepped stylet was replaced by the custom-made stepped needle, which was used for the IG CED. Initial dye injections performed in pig cadavers confirmed the accuracy of DRG targeting under CT guidance. Intraganglionic administration of adeno-associated virus in vivo resulted in a unilateral transduction of the injected DRG, with 33.5% DRG neurons transduced. Transgene expression was also found in the dorsal root entry zones at the corresponding spinal levels. The results thereby confirm the efficacy of CED by the stepped needle and a selectivity of DRG targeting. Imaging-based modeling of the procedure in humans suggests that IG CED may be translatable to the clinical setting.

AbstractBackground and ObjectivesPrevious studies have established the relationship between tobacco use and pain severity among patients suffering from chronic pain. Unfortunately, many physicians feel underprepared to counsel patients on smoking cessation. The purpose of this study was to identify the attitudes, beliefs, and practices of pain medicine fellowship directors in regard to tobacco control interventions and trainee education.MethodsProgram directors of ACGME‐accredited pain medicine fellowships were surveyed via a web‐based form to assess current practices in tobacco intervention and to gauge interest in incorporating tobacco control into their current fellowship training curriculum.ResultsOf the respondents, the majority indicated that they frequently asking their patients about tobacco use and advise them to quit. In addition, most agreed that presenting tobacco control is a responsibility of pain physicians. However, few consistently provided any assistance with quitting. Finally, the majority of program directors felt that pain medicine fellowships should include tobacco control training and were interested in incorporating an educational module about smoking and pain into their training program.ConclusionsThis survey of pain medicine fellowship program directors indicates that although smoking cessation interventions are not being consistently applied in academic pain practices, there is a strong interest in doing so. Furthermore, the majority of program directors recognized the importance of incorporating tobacco control training into pain medicine fellowships. This recognition may provide an opportunity to develop a web‐based training module that could be easily incorporated into the upcoming milestones in pain medicine training.

AbstractChronic pain is common in persons with HIV and is often associated with psychiatric illness and substance abuse. Current literature links psychiatric illness and substance abuse with worse HIV outcomes; however, the relationship of chronic pain, alone and in the context of psychiatric illness and substance abuse, to outcomes in HIV has not been described. To develop this new area of inquiry, we propose an adapted biopsychosocial framework specifically for chronic pain in HIV. This framework will describe these relationships and serve as a conceptual framework for future investigations.

Cigarette smoke, which serves as a nicotine delivery vehicle in humans, produces profound changes in physiology. Experimental studies suggest that nicotine has analgesic properties. However, epidemiologic evidence shows that smoking is a risk factor for chronic pain. The complex relationship between smoking and pain not only is of scientific interest, but also has clinical relevance in the practice of anesthesiology and pain medicine. This review will examine current knowledge regarding how acute and chronic exposure to nicotine and cigarette smoke affects acute and chronic painful conditions. It will cover the relevant pharmacology of nicotine and other ligands at the nicotinic acetylcholine receptor as related to pain, explore the association of cigarette smoking with chronic painful conditions and potential mechanisms to explain this association, and examine clinical implications for the care of smokers with pain.

Objective: The five-factor model of personality was used to describe the correlates of smoking abstinence. Methods: Following treatment in the Mayo Clinic Nicotine Dependence Center, the six month abstinence status was determined by self-report. Sixteen months to 2.4 years following the initial treatment evaluation, and 10 months to 1.9 years after the abstinence status was determined, 475 patients were mailed a Neuroticism, Extraversion, Openness, Five-Factor Inventory questionnaire. Ninety-nine abstinent and 151 smoking patients returned a completed questionnaire. Results: Multivariate analysis showed that low scores on neuroticism and openness were associated with tobacco abstinence. In addition, high scores on neuroticism and low scores on agreeableness and conscientiousness were associated with predictors of poor outcome including greater number of cigarettes smoked per day, initiation of smoking prior to age 18, and a Fagerström Test for Nicotine Dependence score of ≥ 6. Conclusions: Personality characteristics as predictors of smoking abstinence following treatment warrant further investigation in prospective clinical trails. Treatment matching using personality profiling as a guide may be a valuable tool for improving abstinence rates following treatment for nicotine dependence.