The National Academy of Sciences through its Institute of Medicine (IOM) has produced a major scholarly assessment of pain in America. This document is a tremendous contribution to the evolving nec...

Relieving pain in america: a blueprint for transforming prevention, care, education, and research

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It has long been appreciated that the experience of pain is highly variable between individuals. Pain results from activation of sensory receptors specialized to detect actual or impending tissue damage (i.e., nociceptors). However, a direct correlation between activation of nociceptors and the sensory experience of pain is not always apparent. Even in cases in which the severity of injury appears similar, individual pain experiences may vary dramatically. Emotional state, degree of anxiety, attention and distraction, past experiences, memories, and many other factors can either enhance or diminish the pain experience. Here, we review evidence for "top-down" modulatory circuits that profoundly change the sensory experience of pain.

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Central modulation of pain

Methods and apparatus are provided for renal neuromodulation using a pulsed electric field to effectuate electroporation or electrofusion. It is expected that renal neuromodulation (e.g., denervation) may, among other things, reduce expansion of an acute myocardial infarction, reduce or prevent the onset of morphological changes that are affiliated with congestive heart failure, and/or be efficacious in the treatment of end stage renal disease. Embodiments of the present invention are configured for percutaneous intravascular delivery of pulsed electric fields to achieve such neuromodulation.

Methods and apparatus for renal neuromodulation

https://www.thelancet.com/pdfs/journals/lancet/PIIS0140-6736(11)60402-9.pdf

Treatment of chronic non-cancer pain

Acute differential modulation of synaptic transmission and cell survival during exposure to pulsed and continuous radiofrequency energy

Objective. Pulsed radiofrequency, where short bursts of radiofrequency energy are applied to nervous tissue, has been used by pain practitioners as a non- or minimally neurodestructive technique, alternative to radiofrequency heat lesions. Clinical advantages and mechanisms of this treatment remain unclear. The objective of this study was to review current clinical and laboratory data.

Design. We systematically searched the MEDLINE database (PubMed) and tables of contents of electronically available pain journals. Reference lists of relevant reports and international scientific pain congress abstract books were also hand searched. Only those reports on pulsed radiofrequency were withheld.

Results. The final analysis yielded 58 reports on the clinical use of pulsed radiofrequency in different applications: 33 full publications and 25 abstracts. We also retrieved six basic science reports, five full publications, and one abstract.

Conclusions. The accumulation of these data shows that the use of pulsed radiofrequency generates an increasing interest of pain physicians for the management of a variety of pain syndromes. Although the mechanism of action has not been completely elucidated, laboratory reports suggest a genuine neurobiological phenomenon altering the pain signaling, which some have described as neuromodulatory. No side effects related to the pulsed radiofrequency technique were reported to date. Further research in the clinical and biological effects is justified.

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Pulsed radiofrequency: current clinical and biological literature available.

"Chronic" low back pain (LBP), defined as present for 3 or more months, has become a major socioeconomic problem insufficiently addressed by five major entities largely working in isolation from one another - procedural based specialties, strength based rehabilitation, cognitive behavioral therapy, pain management and manipulative care. As direct and indirect costs continue to rise, many authors have systematically evaluated the body of evidence in an effort to demonstrate the effectiveness (or lack thereof) for various diagnostic and therapeutic interventions. The objective of this Spine Focus issue is not to replicate previous work in this area. Rather, our expert panel has chosen a set of potentially controversial topics for more in-depth study and discussion. A recurring theme is that chronic LBP is a heterogeneous condition, and this affects the way it is diagnosed, classified, treated, and studied. The efficacy of some treatments may be appreciated only through a better understanding of heterogeneity of treatment effects (i.e., identification of clinically relevant subgroups with differing responses to the same treatment). Current clinical guidelines and payer policies for LBP are systematically compared for consistency and quality. Novel approaches for data gathering, such as national spine registries, may offer a preferable approach to gain meaningful data and direct us towards a "results-based medicine." This approach would require more high-quality studies, more consistent recording for various phenotypes and exploration of studies on genetic epidemiologic undertones to guide us in the emerging era of "results based medicine."

Chronic low back pain: a heterogeneous condition with challenges for an evidence-based approach.

Many women undergo cesarean delivery without problems, however some experience significant pain after cesarean section. Pain is associated with negative short-term and long-term effects on the mother. Prior to women undergoing surgery, can we predict who is at risk for developing significant postoperative pain and potentially prevent or minimize its negative consequences? These are the fundamental questions that a team from the University of Washington, Stanford University, the Catholic University in Brussels, Belgium, Santa Joana Women's Hospital in Sao Paulo, Brazil, and Rambam Medical Center in Israel is currently evaluating in an international research collaboration. The ultimate goal of this project is to provide optimal pain relief during and after cesarean section by offering individualized anesthetic care to women who appear to be more 'susceptible' to pain after surgery. A significant number of women experience moderate or severe acute post-partum pain after vaginal and cesarean deliveries. (1) Furthermore, 10-15% of women suffer chronic persistent pain after cesarean section. (2) With constant increase in cesarean rates in the US (3) and the already high rate in Brazil, this is bound to create a significant public health problem. When questioning women's fears and expectations from cesarean section, pain during and after it is their greatest concern. (4) Individual variability in severity of pain after vaginal or operative delivery is influenced by multiple factors including sensitivity to pain, psychological factors, age, and genetics. The unique birth experience leads to unpredictable requirements for analgesics, from 'none at all' to 'very high' doses of pain medication. Pain after cesarean section is an excellent model to study post-operative pain because it is performed on otherwise young and healthy women. Therefore, it is recommended to attenuate the pain during the acute phase because this may lead to chronic pain disorders. The impact of developing persistent pain is immense, since it may impair not only the ability of women to care for their child in the immediate postpartum period, but also their own well being for a long period of time. In a series of projects, an international research network is currently investigating the effect of pregnancy on pain modulation and ways to predict who will suffer acute severe pain and potentially chronic pain, by using simple pain tests and questionnaires in combination with genetic analysis. A relatively recent approach to investigate pain modulation is via the psychophysical measure of Diffuse Noxious Inhibitory Control (DNIC). This pain-modulating process is the neurophysiological basis for the well-known phenomenon of 'pain inhibits pain' from remote areas of the body. The DNIC paradigm has evolved recently into a clinical tool and simple test and has been shown to be a predictor of post-operative pain.(5) Since pregnancy is associated with decreased pain sensitivity and/or enhanced processes of pain modulation, using tests that investigate pain modulation should provide a better understanding of the pathways involved with pregnancy-induced analgesia and may help predict pain outcomes during labor and delivery. For those women delivering by cesarean section, a DNIC test performed prior to surgery along with psychosocial questionnaires and genetic tests should enable one to identify women prone to suffer severe post-cesarean pain and persistent pain. These clinical tests should allow anesthesiologists to offer not only personalized medicine to women with the promise to improve well-being and satisfaction, but also a reduction in the overall cost of perioperative and long term care due to pain and suffering. On a larger scale, these tests that explore pain modulation may become bedside screening tests to predict the development of pain disorders following surgery.

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Alex Cahana

Papers

Treatment of chronic non-cancer pain

Acute differential modulation of synaptic transmission and cell survival during exposure to pulsed and continuous radiofrequency energy

Pulsed radiofrequency: current clinical and biological literature available.

Chronic low back pain: a heterogeneous condition with challenges for an evidence-based approach.

An experimental paradigm for the prediction of Post-Operative Pain (PPOP).