Conquering pain

Neuropathic pain and deep brain stimulation

Deep brain stimulation (DBS) is a neurosurgical intervention the efficacy, safety, and utility of which are established in the treatment of Parkinson's disease. For the treatment of chronic, neuropathic pain refractory to medical therapies, many prospective case series have been reported, but few have published findings from patients treated with current standards of neuroimaging and stimulator technology over the last decade . We summarize the history, science, selection, assessment, surgery, programming, and personal clinical experience of DBS of the ventral posterior thalamus, periventricular/periaqueductal gray matter, and latterly rostral anterior cingulate cortex (Cg24) in 113 patients treated at 2 centers (John Radcliffe, Oxford, UK, and Hospital de São João, Porto, Portugal) over 13 years. Several experienced centers continue DBS for chronic pain, with success in selected patients, in particular those with pain after amputation, brachial plexus injury, stroke, and cephalalgias including anesthesia dolorosa. Other successes include pain after multiple sclerosis and spine injury. Somatotopic coverage during awake surgery is important in our technique, with cingulate DBS under general anesthesia considered for whole or hemibody pain, or after unsuccessful DBS of other targets. Findings discussed from neuroimaging modalities, invasive neurophysiological insights from local field potential recording, and autonomic assessments may translate into improved patient selection and enhanced efficacy, encouraging larger clinical trials.

Deep brain stimulation for pain

Deep brain stimulation (DBS) is a neurosurgical intervention whose efficacy, safety, and utility have been shown in the treatment of movement disorders. For the treatment of chronic pain refractory to medical therapies, many prospective case series have been reported, but few have published findings from patients treated during the past decade using current standards of neuroimaging and stimulator technology. We summarize the history, science, selection, assessment, surgery, and personal clinical experience of DBS of the ventral posterior thalamus, periventricular/periaqueductal gray matter, and, latterly, the rostral anterior cingulate cortex (Cg24) in 100 patients treated now at two centers (John Radcliffe Hospital, Oxford, UK, and Hospital de São João, Porto, Portugal) over 12 years. Several experienced centers continue DBS for chronic pain with success in selected patients, in particular those with pain after amputation, brachial plexus injury, stroke, and cephalalgias including anesthesia dolorosa. Other successes include pain after multiple sclerosis and spine injury. Somatotopic coverage during awake surgery is important in our technique, with cingulate DBS considered for whole-body pain or after unsuccessful DBS of other targets. Findings discussed from neuroimaging modalities, invasive neurophysiological insights from local field potential recording, and autonomic assessments may translate into improved patient selection and enhanced efficacy, encouraging larger clinical trials.

Management of chronic limb pain with spinal cord stimulation

BACKGROUND

Spinal Cord Stimulation (SCS) is a treatment option for chronic pain patients. The most common indication for SCS is the failed back syndrome with leg pain. In the last decade, advances in our understanding of appropriate stimulation programming, lead placement and the physiology of SCS, have led to changes in multi-site stimulation, and stimulation with differing programs. In the past, low back, axial neuropathic type pain was not responsive to SCS. With dual electrode arrays, and dual stimulation with alternating programs of stimulation, steering of stimulation paresthesia, and versatile programmable stimulation parameters, SCS has become a more versatile form of analgesia.

PURPOSE

To describe the current treatment rational for SCS and the results of that treatment.

RESULTS

The SCS is most efficient in patients with neuropathic pain of the extremities and less efficacious in patients with axial pain.

CONCLUSION

SCS is the most effective treatment for limb pain not amenable to surgical decompression. The success of SCS in this chronic pain group is 80% successful in treatment of leg pain, and much less effective in treatment of axial pain.

Pain assessment in the perspective of action science

Pain assessment is examined in the perspective of action science with the aim to discover espoused theories and theories-in-use for pain assessment. In action science there are 2 sets of theories of action: espouse theories and theories-in-use, which often exist in practice inconsistently with each other resulting in haphazard actions. Espoused theories of pain and pain assessment and a set of theories-in-use were revealed. Alignments between the espoused theories and the theories-in-use, and disparities between these theories were found in the pain assessment situations. The findings point to possible explanations regarding problems in pain assessment, and provide insights into our understanding of nursing practice especially in relation to pain assessment.

Strategies in assessing post operative pain—A South African study

The purpose of this validation study was to describe strategies used in postoperative pain assessment among a group of nurses in South Africa. A mixed qualitative and quantitative study was conducted in a 950-bed academic hospital complex. Surgical nurses (n = 12) carried out pain assessments of postoperative patients (n = 36) in pain. Data were collected using detailed interviews and pain intensity was estimated on a visual analogue scale (VAS, 0-10 cm). Nurses used four categories of criteria (a) how the patient looks, (b) what the patient says, (c) the patient's way of talking, and (d) experience of similar circumstances and drew on their past experiences in five different ways: (a) some patients report lower pain intensity than expected, (b) a typology of patients, (c) a focus on listening to patients, (d) what to look for, and (e) what to do for patients were identified. The system of categories described by Sjöström [Sjöström B. Assessing acute postoperative pain. Assessment strategies and quality of clinical experience and professional role. Göteborg: Acta Universitatis Gothoburgensis; 1995] was valid for this sample with an additional category. The different categories seem to be complementary and necessary for assessing pain in others. The findings have implications for professionals who provide care for patients in pain.

Deep brain stimulation for chronic pain: results of two multicenter trials and a structured review

OBJECTIVES

A U.S. Food and Drug Administration ruling required clinical trials to evaluate the safety and efficacy of deep brain stimulation devices, thereby limiting treatment to the investigational setting.

INTRODUCTION

As an investigator in two clinical trials of deep brain stimulation, I sought to determine why pain remained an unapproved indication despite regulatory approval of the same device for tremor.

METHODS

The results of two multicenter trials of deep brain stimulation for pain were analyzed, and the pertinent literature was reviewed using published guidelines for the evaluation of clinical trial reports.

RESULTS

The first-generation Model 3380 lead trial enrolled 196 patients; the current Model 3387 trial enrolled 50 patients. Prospectively defined criteria for success included at least half of patients reporting >/=50% pain relief at 1 year. Manufacture of the Model 3380 lead was discontinued, and the 3387 trial closed early because of slow enrollment, high attrition, and low efficacy. When results were analyzed according to the study plan, neither trial was successful. Consequently, deep brain stimulation has not been approved for pain control by the U.S. Food and Drug Administration.

CONCLUSIONS

Deep brain stimulation has not been shown to produce effective long-term pain relief. Future studies of motor cortex stimulation and similar therapies will require appropriate control groups and accepted methods of data collection and analysis to support claims that predictable and reliable analgesic effects are produced in humans.

Strategies of Pain Assessment Used by Nurses on Surgical Units

The purpose of this study was to identify the criteria nurses actually used to assess postoperative pain and the kind of knowledge they drew on from past experience. A series of semistructured interviews were performed with 10 nurses while they conducted pain assessments with 30 postsurgical patients. Data were analyzed on the basis of Dahlgren and Fallsberg's (1991) analytic approach called phenomenography. Findings were compared with Sjostrom's 1995 study of nurses in Sweden. Nurses in this study, much like the group in Sweden, used three categories of criteria (i.e., how the patient looked, what the patient said, and experience with similar circumstances) and drew on their past experiences in four different ways (i.e., in terms of a typology of patients, a focus on listening to patients, what to look for, and what to do for patients) when assessing postoperative pain. In the most frequently reported strategy, nurses relied on criteria related to the patient's appearance and drew on their past experience in terms of what physical signs to look for (e.g., facial expressions, bodily movement, and heart rate). The variety of strategies used by nurses in this study opens an avenue for further investigating the linkage between underlying conceptions of pain (as essentially subjective vs. objective phenomenon) and the quality and effectiveness of nurses' assessments of pain and its management in postoperative and other contexts across nursing.