Spinal cord stimulation (SCS) is a minimally invasive therapy used for the treatment of chronic neuropathic pain. SCS is a safe and effective alternative to medications such as opioids, and multiple randomized controlled studies have demonstrated efficacy for difficult-to-treat neuropathic conditions such as failed back surgery syndrome. Conventional SCS is believed mediate pain relief via activation of dorsal column Aβ fibers, resulting in variable effects on sensory and pain thresholds, and measurable alterations in higher order cortical processing. Although potentiation of inhibition, as suggested by Wall and Melzack's gate control theory, continues to be the leading explanatory model, other segmental and supraspinal mechanisms have been described. Novel, non-standard, stimulation waveforms such as high-frequency and burst have been shown in some studies to be clinically superior to conventional SCS, however their mechanisms of action remain to be determined. Additional studies are needed, both mechanistic and clinical, to better understand optimal stimulation strategies for different neuropathic conditions, improve patient selection and optimize efficacy.

Spinal Cord Stimulation: Clinical Efficacy and Potential Mechanisms.

The transversus abdominis plane (TAP) block is a relatively new regional anesthesia technique that provides analgesia to the parietal peritoneum as well as the skin and muscles of the anterior abdominal wall. It has a high margin of safety and is technically simple to perform, especially under ultrasound guidance. A growing body of evidence supports the use of TAP blocks for a variety of abdominal procedures, yet, widespread adoption of this therapeutic adjunct has been slow. In part, this may be related to the limited sources for anesthesiologists to develop an appreciation for its sound anatomical basis and the versatility of its clinical application. As such, we provide a brief historical perspective on the TAP block, describe relevant anatomy, review current techniques, discuss pharmacologic considerations, and summarize the existing literature regarding its clinical utility with an emphasis on recently published studies that have not been included in other systematic reviews or meta-analyses.

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Clinical implications of the transversus abdominis plane block in adults.

Botulinum toxin (BoNT) has been used as a treatment for excessive muscle stiffness, spasticity, and dystonia. BoNT for approximately 40 years, and has recently been used to treat various types of neuropathic pain. The mechanism by which BoNT acts on neuropathic pain involves inhibiting the release of inflammatory mediators and peripheral neurotransmitters from sensory nerves. Recent journals have demonstrated that BoNT is effective for neuropathic pain, such as postherpetic neuralgia, trigeminal neuralgia, and peripheral neuralgia. The purpose of this review is to summarize the experimental and clinical evidence of the mechanism by which BoNT acts on various types of neuropathic pain and describe why BoNT can be applied as treatment. The PubMed database was searched from 1988 to May 2017. Recent studies have demonstrated that BoNT injections are effective treatments for post-herpetic neuralgia, diabetic neuropathy, trigeminal neuralgia, and intractable neuropathic pain, such as poststroke pain and spinal cord injury.

Botulinum Toxin for the Treatment of Neuropathic Pain

Botulinum toxin A, brain and pain.

Introduction
Intrathecal therapy is an important part of the pain treatment algorithm for chronic disease states. The use of this option is a viable treatment strategy, but it is inherent for pain physicians to understand risk assessment and mitigation. In this manuscript, we explore evidence and mitigating strategies to improve safety with intrathecal therapy.

Methods
A robust literature search was performed covering January 2011 to October 9, 2016, in PubMed, Embase, MEDLINE, Biomed Central, Google Scholar, Current Contents Connect, and International Pharmaceutical Abstracts. The information was cross-referenced and compiled for evidence, analysis, and consensus review, with the intent to offer weighted recommendations and consensus statements on safety for targeted intrathecal therapy delivery.

Results
The Polyanalgesic Consensus Conference has made several best practice recommendations to improve care and reduce morbidity and mortality associated with intrathecal therapy through all phases of management. The United States Prevention Service Task Force evidence level and consensus strength assessments are offered for each recommendation.

Conclusion
Intrathecal therapy is a viable and relatively safe option for the treatment of cancer- and noncancer-related pain. Continued research and expert opinion are required to improve our current pharmacokinetic and pharmacodynamic model of intrathecal drug delivery, as this will undoubtedly improve safety and efficacy.

The Polyanalgesic Consensus Conference (PACC): Recommendations for Intrathecal Drug Delivery: Guidance for Improving Safety and Mitigating Risks.

Objectives Spinal cord stimulation (SCS) for patients with failed back surgery syndrome (FBSS) show variable results and limited to moderate evidence. In the last years the stimulation of high frequency (HF) has been considered as a better alternative in this pathology for its supposed benefits compared to the stimulation with conventional frequency (CF). To compare in one year follow-up, the efficacy of high-frequency SCS (HF) versus conventional frequency SCS (CF) on the patients with FBSS. Design Prospective, Randomized blind trial. Setting Academic University Pain Medicine Center. Subject Seventy eight patients with FBSS diagnosis based on internationally recognized criteria, and refractory to conservative therapy for at least 6 months, have been initially recruited, and. Methods Sixty subjects met the eligibility criteria and were randomized and scheduled for the trial phase.The patients were randomly assigned in either, one of the two groups: CF SCS or HF SCS. Within the study methods, special attention was paid to standardizing patient programming, so that these parameters would not impact the results.The trial period was considered successful if there was ?50% reduction in the NRS from baseline. Results A total of 55 subjects successfully completed all assessments during one year follow-up. Change patterns in scores do not differ based on high versus conventional frequency, with significant global average reduction at 1 year similarly for both groups. Among all the items included in the Short Form-12 questionnaire (SF-12), only the variations in the social function score between the instants t1 and t2 are somewhat higher in the high frequency group. Conclusion The evolutionary pattern of the different parameters studied in our patients with FBSS does not differ according to their treatment by spinal stimulation, with conventional or high frequency, in one year follow-up.

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Prospective, Randomized Blind Effect-on-Outcome Study of Conventional vs High-Frequency Spinal Cord Stimulation in Patients with Pain and Disability Due to Failed Back Surgery Syndrome.

Objective
We searched the medical literature from the last 15 years (1998 to 2013) relating to the etiology, diagnosis, and treatment of vulvodynia. The evidence was reviewed supporting the therapeutic proposals currently in use and propose the incorporation of novel, minimally invasive, interventional therapies, within the context of a multidisciplinary approach.

Methods
This was a systematic review of all relevant studies with no language restrictions. Studies were identified through Medline/PubMed (1998 to March 2013), the Cochrane Library (2001 to 2013), and conference records and book chapters. The keywords used included “chronic pelvic pain,” “vulvodynia,” “vestibulodynia,” and search terms “etiology,” “diagnosis,” and “treatment” were added. The levels of evidence were assessed using grading system for “Therapy/Prevention/Etiology/Harm” developed by the Centre for Evidence-Based Medicine (CEBM). The grading system assists in clinical decision-making, and we decided to use “The Grading of Recommendations Assessment, Development, and Evaluation (GRADE).”

Results
A total of 391 papers were assessed. Of these, 215 were analyzed and 175 were excluded, as they pertained to areas not directly related to the disease under review.

Conclusion
The optimal therapy for vulvar pain syndrome remains elusive, with low percentages of therapeutic success, using either local or systemic pharmacological approaches. Surgery involving invasive and often irreversible therapeutic procedures has resulted in success for certain subtypes of vulvodynia. We present a multidisciplinary approach whereby pain treatment units may provide an intermediate level of care between standard medical and surgical treatments.

Vulvodynia—An Evidence-Based Literature Review and Proposed Treatment Algorithm

▪ : Supraorbital neuralgia has been identified as an infrequent cause of headache that may prove very difficult to control pharmacologically. Peripheral nerve stimulation using electrodes to stimulate the nerve segmentally responsible for the zone of pain may constitute a management alternative in such cases. We present the case of a patient with headache because of posttraumatic supraorbital neuralgia, refractory to medical treatment, with good analgesic control after peripheral nerve stimulation.



Peripheral nerve stimulation may be considered a safe, reversible treatment for patients with headache secondary to supraorbital neuralgia who respond poorly to pharmacological treatment, thus avoiding irreversible alternatives such as surgery. ▪

Peripheral Neurostimulation in Supraorbital Neuralgia Refractory to Conventional Therapy

Objective Botulinum toxin is a neurotoxin that has been widely used in chronic pain for the treatment of multiple conditions with a component of localized muscle spasm. Recent studies suggest that botulinum toxin is effective in the treatment of neuropathic pain syndromes such as postherpetic neuralgia or painful scars. Methods We searched the PubMed and OvidSP databases. We also included cross-referencing bibliographies from primary and review articles. Discussion In this descriptive review, we evaluate the usefulness, safety, and potential pathophysiological mechanism of botulinum toxin type A for treatment of painful disorders with neuropathic component such as postherpetic neuralgia, diabetic neuropathy, or trigeminal neuralgia. Conclusions On the basis of the analysis of the reports published in the literature, it would seem that fractioned peripheral subcutaneous and perineural injections of botulinum toxin type A may be useful for the treatment of various chronic pain conditions with neuropathic component.

Subcutaneous and perineural botulinum toxin type a for neuropathic pain: a descriptive review.

Objective: Botulinum toxin is a neurotoxin that has been widely used in chronic pain for the treatment of multiple conditions with a component of localized muscle spasm. Recent studies suggest that botulinum toxin is effective in the treatment of neuropathic pain syndromes such as post-herpetic neuralgia.

Case Report:  We report the case of a 67-year-old man who underwent atypical segmentectomy of a right lower lobe lung nodule. The patient was referred to our pain management department with a of 2-year history persistent pain along the thoracotomy scar having a predominantly neuropathic component, refractory to standard treatments. He was successfully treated with subcutaneous botulinum toxin type A.

Discussion:  On the basics of our own experience and on the analysis of the reports published in the literature, fractioned subcutaneous injections of botulinum toxin may be useful for the treatment of various chronic localized pain conditions including chronic post-thoracotomy pain.

J.M. Asensio-Samper

Papers

Prospective, Randomized Blind Effect-on-Outcome Study of Conventional vs High-Frequency Spinal Cord Stimulation in Patients with Pain and Disability Due to Failed Back Surgery Syndrome.

Vulvodynia—An Evidence-Based Literature Review and Proposed Treatment Algorithm

Peripheral Neurostimulation in Supraorbital Neuralgia Refractory to Conventional Therapy

Subcutaneous and perineural botulinum toxin type a for neuropathic pain: a descriptive review.

Subcutaneous botulinum toxin for chronic post-thoracotomy pain.