The Polyanalgesic Consensus Conference (PACC): Recommendations for Trialing of Intrathecal Drug Delivery Infusion Therapy.

INTRODUCTION: Intrathecal (IT) drug infusion is an appropriate and necessary tool in the algorithm to treat refractory cancer and noncancer pain. The decision-making steps/methodology for selecting appropriate patients for implanted targeted drug delivery systems is controversial and complicated. Therefore, a consensus on best practices for determining appropriate use of IT drug infusion may involve testing/trialing this therapy before implantation. METHODS: This current Polyanalgesic Consensus Conference (PACC) update was designed to address the deficiencies and emerging innovations since the previous PACC convened in 2012. A literature search identified publications available since the previous PACC publications in 2014, and relevant sources were contributed by the PACC members. After reviewing the literature, the panel determined the evidence levels and degrees of recommendations. The developed consensus was ranked as strong (>80%), moderate (50-79%), or weak (<49%). RESULTS: The trialing for IT drug delivery systems (IDDS) remains an area of continued controversy. The PACC recommendations for trialing are presented in 34 consensus points and cover trialing for morphine, ziconotide, and medication admixtures; starting doses and titration practices; measurements of success; trial settings and monitoring; management of systemic opioids during trialing; and the role of psychological evaluation. Finally, the PACC describes clinical scenarios in which IT trialing is required or not required. CONCLUSION: The PACC provides consensus guidance on best practices of trialing for IDDS implants. In addition, the PACC recommends that no trial may be required in certain patient populations.

The Polyanalgesic Consensus Conference (PACC): Recommendations on Intrathecal Drug Infusion Systems Best Practices and Guidelines.

INTRODUCTION: Pain treatment is best performed when a patient-centric, safety-based philosophy is used to determine an algorithmic process to guide care. Since 2007, the International Neuromodulation Society has organized a group of experts to evaluate evidence and create a Polyanalgesic Consensus Conference (PACC) to guide practice. METHODS: The current PACC update was designed to address the deficiencies and innovations emerging since the previous PACC publication of 2012. An extensive literature search identified publications between January 15, 2007 and November 22, 2015 and authors contributed additional relevant sources. After reviewing the literature, the panel convened to determine evidence levels and degrees of recommendations for intrathecal therapy. This meeting served as the basis for consensus development, which was ranked as strong, moderate or weak. Algorithms were developed for intrathecal medication choices to treat nociceptive and neuropathic pain for patients with cancer, terminal illness, and noncancer pain, with either localized or diffuse pain. RESULTS: The PACC has developed an algorithmic process for several aspects of intrathecal drug delivery to promote safe and efficacious evidence-based care. Consensus opinion, based on expertise, was used to fill gaps in evidence. Thirty-one consensus points emerged from the panel considerations. CONCLUSION: New algorithms and guidance have been established to improve care with the use of intrathecal drug delivery.

A Prospective, Randomized, Single-Blinded, Head-to-Head Long-Term Outcome Study, Comparing Intrathecal (IT) Boluses With Continuous Infusion Trialing Techniques Prior to Implantation of Drug Delivery Systems (DDS) for the Treatment of Severe Intractable Chronic Nonmalignant Pain.

OBJECTIVE: The study aims to compare intrathecal (IT) boluses to continuous infusion trialing techniques prior to implantation of drug delivery systems (DDS) for the treatment of severe intractable chronic nonmalignant pain. DESIGN: This is a prospective, randomized, head-to-head long-term outcome study. MATERIALS AND METHODS: Forty patients with comparable patient demographics were randomly assigned to two cohorts. Cohort A trialed with intermittent boluses; Cohort B trialed with continuous infusion. One patient failed trial in each group. Nineteen patients were implanted in each group. Follow-up was for 36 months with intervals at 6, 12, 18, 24, 36 months. The Brief Pain Inventory was used was used for assessment. OUTCOME MEASURES: We used the Brief Pain Inventory to measure pain (worst and average), physical function (walking, normal work, and general activity), behavioral function (mood, sleep, and relations with others), IT dose, and oral opioid use. RESULTS: We observed statistically significant reduction in pain and improvement of function in both cohorts following DDS implantation throughout the observation period. The IT dose remained virtually unchanged throughout as well, with overall limited dose escalation. Oral opioid use was significantly reduced. There was no statistically significant difference in prediction of trial success or long-term outcomes between the two cohorts. CONCLUSION: Low-dose IT opioids via DDS can provide significant and long-lasting reduction in pain, and improvement in function (physical and behavioral) for patients with chronic nonmalignant pain. The two trialing techniques tested, intermittent boluses, and continuous infusion delivered intrathecally showed no clinical significance difference in terms of predicting trial success or long-term outcomes.

Chronic Pain as a Hypothetical Construct: A Practical and Philosophical Consideration.

Pain has been defined by the International Association for the Study of Pain (IASP) as "an unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage." Chronic pain is usually described as pain that has persisted for 3-6 months and/or beyond the expected time of healing. The numerical pain rating (NPR) is the customary metric and often considered as a proxy for the subjective experience of chronic pain. This definition of pain (chronic) has been of significant heuristic value. However, the definition and the models it has spawned tend to encourage the interpretation of pain as a measurable entity and implies that the patient's experience of pain can be fully comprehended by someone other than the person in pain. Several major models of pain have been scrutinized and found to propagate the notion of pain as a 'thing' and fall prey to biomedical reductionism and Cartesian (mind-body) dualism. Furthermore, the NPR does not appear to capture the complexity of chronic pain and correlates poorly with other clinically meaningful outcomes. It, and other aspects of the current notion of chronic pain, appear to be an extension of our reliance on the philosophical principles of reductionism and materialism. These and other shortcomings identified in the IASP definition have resulted in an increased interest in a reexamination and possible updating of our view of pain (chronic) and its definition. The present paper describes an alternative view of pain, in particular chronic pain. It argues that chronic pain should be understood as a separate phenomenon from, rather than an extension of, acute pain and interpreted as a hypothetical construct (HC). HCs are contrasted to intervening variables (IV) and the use of HCs in science is illustrated. The acceptance of the principles of nonlinearity and emergence are seen as important characteristics. The practical implications and barriers of this philosophical shift for assessment, treatment, and education are explored. The patient's narrative is presented as a potential source of important phenomenological data relating to their 'experience' of pain. It is further proposed that educational and academic endeavors incorporate a discussion of the process of chronification and the role of complexity theory.

Psychological factors in spinal cord stimulation therapy: brief review and discussion.

Since its introduction in 1967 by Shealy and colleagues, spinal cord stimulation (SCS) therapy has become an accepted approach to the treatment of certain types of chronic pain. Significant advances have been made in surgical technique, hardware technology, and the variety of disorders for which SCS has proven to be potentially beneficial. Despite these advancements, 25 to 50% of patients in whom a preimplantation trial screening yields successful results report loss of analgesia within 12 to 24 months of implantation, even in the presence of a functioning device. Psychological factors may play an important role in understanding this observation and improving the outcomes. In this article the author briefly reviews some of the data on psychological factors potentially involved in SCS. Research on patients with low-back and extremity pain was more heavily relied on because this is the population for which the most data exist. The discussion is divided into four sections: 1) role of psychological factors; 2) psychological screening and assessment; 3) patient selection and psychological screening; and 4) psychological variables and outcomes. To date, the data remain speculative. Although few definitive conclusions can be drawn, the cumulative existing experience does lend itself to some reasonable recommendations. As with all therapies for chronic pain, invasive or noninvasive, the criteria for success and an acceptable level of failure need to be established, but remain elusive. The emphasis herein is to try to take what works and make it work better.

Pain tolerance as a predictor of outcome following multidisciplinary treatment for chronic pain: differential effects as a function of sex.

Sex-related differences in the experience of clinical and experimental pain have been widely reported. Females are at elevated risk for developing several chronic pain conditions and women demonstrate greater sensitivity to noxious stimulation in the laboratory. However, relationships between responses to experimental noxious stimuli and the experience of clinical pain have not been well characterized. One previous study of healthy adults indicated that pain threshold and tolerance were associated with clinical pain among women but not men (i.e. females with lower pain threshold and tolerance reported more clinical pain). In the present investigation, relationships between pain tolerance and outcomes of treatment for chronic pain were evaluated in a sex-dependent manner. Ischemic pain tolerance was assessed prior to treatment in 171 chronic pain patients completing a pain management program. Outcomes were measured as changes in pain severity, affect, and pain-related disability. Over the course of treatment, women demonstrated greater improvement in pain-related disability while men showed more reduction in pain. Ischemic pain tolerance was related to outcome in a sex-specific fashion. Women with higher pain tolerances showed greater improvement in pain, more reduction in pain-related interference, and more increases in activity level than women with lower pain tolerances. In contrast, pain tolerance was not associated with positive treatment outcomes among men. These results indicate that experimental pain responses may be most clinically relevant for women, and that sex differences may exist in the determinants of pain-treatment outcomes.

Exercise quotas, anticipatory concern and self-efficacy expectancies in chronic pain: a preliminary report.

Reduced activity levels are a frequently encountered problem among chronic pain patients which has been shown to be responsive to exercise quota systems. This study extends the knowledge of exercise quota systems by examining their effects on beliefs relevant to exercise avoidance. Results indicate that exercise quota systems produce systematic increases in both exercise levels and expectancies of capability while reducing worry and concern about exercising. These data highlight the importance of avoidance learning in chronic pain and suggest that the effectiveness of exercise quota systems is related to a deconditioning process based on exposure rather than the process of applying reinforcement to quota achievement.

The role of self-efficacy expectancies in the prediction of pain tolerance.

The association of self-efficacy expectancies with pain tolerance on the cold pressor test was examined during treatment conditions of setting quotas alone and in conjunction with monetary reinforcement and placebos in 64 college volunteers. It was found that quota setting was an effective means of increasing cold pressor pain tolerance. The addition of monetary reinforcement of quota achievement did not enhance performance, while the addition of a placebo decreased the effectiveness of quota setting. Self-efficacy expectancies were significantly correlated with pain tolerance times and were better predictors of tolerance than pain ratings. Self-efficacy expectancies and pain tolerance times at treatment were both found to predict 1 week follow-up performance.

The effect of two sites of high frequency vibration on cutaneous pain threshold.

The purpose of this study was to evaluate the effect of two sites of high frequency vibration on experimentally produced pain thresholds. Subjects were assigned to one of two experimental groups. Vibration was applied proximal to the site of pain threshold measurement in one group and distal to the measurement site in the other group. The cutaneous pain threshold was measured at the ulnar aspect of the wrist in both groups prior to, during, and following 5 min of vibration. Subjects were 30 right-handed, Caucasian males with a negative history of upper extremity dysfunction. A repeated measures analysis of variance (ANOVA) was used to analyze the data. There was a significant interaction between vibration site and time of pain threshold measurement. Post hoc analysis of that interaction indicated that a significant difference between experimental groups occurred only during vibration; the distal group values were significantly higher than the proximal group values (P less than 0.03). For the distal group, pain threshold values were significantly higher during vibration than pre vibration and post vibration (P less than 0.05). In the proximal group, there was no significant difference in pain threshold values across the 3 time periods. The results of this study indicate that vibration applied distal to the site of pain can provide temporary analgesia.

Spousal responses are differentially associated with clinical variables in women and men with chronic pain.

OBJECTIVES: Spousal responses have been related to clinical variables in patients with chronic pain. For example, solicitous responses from spouses have been associated with greater levels of pain and disability among patients with chronic pain. However, few investigators have determined whether spousal solicitousness produces different effects in women versus men with chronic pain. The present study examined pain reports, medication use, psychosocial factors, functional measures, and pain tolerance in patients with chronic pain. METHODS: Subjects included 114 female and 213 male chronic pain patients, who described their spouses as either high or low in solicitousness on the Multidimensional Pain Inventory. Measures of pain severity, affective distress, physical function, medication use, and pain tolerance were examined in women and men with high versus low scores on spousal solicitousness. RESULTS: Among males only, high spousal solicitousness was associated with greater numerical ratings of pain and greater self-reported disability compared with patients with low solicitous spouses. Among females only, the high spousal solicitousness patients showed lower pain tolerance, greater pain-related interference, poorer performance on functional tasks (eg, timed walking, lifting, and carrying tasks), and greater use of opioid medications. In both women and men, spousal solicitousness was associated with higher scores on the MPI pain severity scale. DISCUSSION: These results extend previous findings demonstrating a relationship between spousal responses and patients' adjustment to pain; however, the pattern of these effects appears to be moderated by the sex of the patient. Implications for assessment and treatment of chronic pain are discussed.

Psychologic evaluation for patients undergoing neuroaugmentative procedures.

Neuroaugmentative and neuromodulation therapy continues to expand. New applications are being found for existing technology, such as the use of SCS therapy in the treatment of head pain. The potential impact of existing therapies is enhanced by new discoveries as exemplified by the availability and demonstrated efficacy of different pharmacologic agents and combinations of agents in intrathecal therapy [39]. Increased attention is being paid to cortical stimulation, including motor cortex stimulation and deep brain stimulation. We must, however, not let our fascination for gadgets betray sound sense. The role of psychosocial factors in the outcome of more "objective" and measurable problems, such as spasticity and tremor versus pain, remains an open area of investigation. Although psychologic issues may not be as prevalent in the amelioration of such problems, they may influence the patient's overall level of satisfaction with the therapy and improvement in quality of life.

Ethnic Group Differences in the Outcomes of Multidisciplinary Pain Treatment.

OBJECTIVES: The aim of this prospective investigation was to evaluate ethnic group differences in pain-related outcomes following multidisciplinary chronic pain treatment. A prospective pre- and post-treatment assessment design was employed to investigate the effects of ethnicity on changes in pain-related variables following completion of a multidisciplinary pain treatment program. METHODS: One hundred fifty five chronic pain patients participating in a multidisciplinary pain treatment program completed measures of pain and mood both prior to and following the four-week treatment. Primary outcome variables included pain severity, pain-related interference, and depressive symptoms. RESULTS: Baseline differences between African-Americans and Whites were observed for depressive symptoms, but not for pain severity or pain-related interference. Following multidisciplinary pain treatment, both White and African-American patients displayed post-treatment reductions in depressive symptoms and pain-related interference. However, White patients also reported reduced pain severity while African-Americans did not. CONCLUSIONS: The treatment approach used in the present study appeared to be less effective in reducing self-reported pain severity in African-American versus White patients, though both groups benefited in terms of reduced depressive symptoms and pain-related interference. Moreover, the observation that improvements in functioning occurred without reductions in pain severity in African-American patients suggests that differences may exist in treatment processes as a function of ethnic group, and will consequently be an important area for future research.

Comprehensive consensus based guidelines on intrathecal drug delivery systems in the treatment of pain caused by cancer pain.

BACKGROUND: Chronic persistent pain as a result of terminal illness, either as a consequence of the disease or the necessary treatment, is common in patients with cancer. For these patients with moderate-to-severe intractable pain, intrathecal (IT) drug delivery systems may represent an effective option for pain management. Thus, IT drug delivery is a viable treatment strategy for both neuropathy and nociceptive pain in the cancer population. However, there is a scarcity of comprehensive guidelines in implanting IT drug delivery systems in the treatment of pain caused by cancer. OBJECTIVE: This article outlines consensus guidelines for the implementation of intrathecal therapy in patients with cancer-related pain and other end of life states causing pain. We highlight the multidisciplinary criteria that warrant careful consideration to ensure meaningful analgesia. METHODS: Evidence was compiled, ranked, and strength considered by an invited panel of well-published and innovative clinician research leaders in pain medicine. Based on that analysis, an accumulation of evidence from observational and randomized prospective trials supports the use of intrathecal (IT) drug delivery to provide effective analgesia for patients with cancer-related pain, including individuals at the end of life. Although not all patients are candidates for this invasive treatment modality, clinicians can determine the appropriateness of proceeding with device implantation by carefully evaluating the individual's overall medical status, psychological stability, social support system, and prognosis of disease. Further, consumption of health care resources and cost-effective treatment is becoming more of a priority; not only is this therapy appropriate medically, but also economically. This multifaceted approach to patient selection assists in maximizing treatment effect and avoiding unintended consequences of therapy. LIMITATIONS: The limitations of these guidelines include that these are of expert panel guidelines. The literature describes appropriate preparation of guidelines based on evidence derived from randomized trials and systematic reviews. However, there is also value for consensus-based guidelines due to non-availability of evidence from either systematic reviews of randomized trials or randomized trials alone. In addition, the evidence is not available on many aspects of intrathecal infusion systems even with observational studies and case reports. Thus, the present approach with expert consensus guidelines is acceptable. CONCLUSIONS: These consensus guidelines are intended to assist clinicians in identifying the candidacy of patients with cancer-related pain and end of life diseases causing pain that may benefit from intrathecal drug delivery. With careful consideration of the patient's medical comorbidities and prior therapies, communication with the oncologist, proper psychological evaluation, and appropriate trialing technique, clinicians can effectively optimize the use of IT therapy for cancer pain. The panel advocates for a much wider application of IT therapy to provide meaningful analgesia for patients with cancer pain, including those at the end of life from a variety of causes.

Catastrophizing, acceptance, and interference: laboratory findings, subjective report, and pain willingness as a moderator.

OBJECTIVE: The present study investigated the effects of both catastrophizing and the pain willingness component of acceptance on interference in daily activities and task performance during experimentally induced ischemic pain. In addition, the potential moderating role of pain willingness on the relationship between catastrophizing and degree of pain interference was also examined. DESIGN: Sixty-seven persons with chronic low back pain completed measures of catastrophizing, acceptance, and daily pain interference. Participants underwent an ischemic pain induction procedure during which a Stroop-like task was administered. MAIN OUTCOME MEASURES: Self-reported pain interference and observed performance on a Stroop-like task during induced pain. RESULTS: The pain willingness component of acceptance and catastrophizing both contributed significantly to self-reports of pain interference. However, levels of pain willingness had an effect much stronger than the negative effects associated with catastrophizing with respect to observed pain interference during induced pain. Results also indicated that pain willingness serves as a moderator in the relationship between catastrophizing and task performance during induced pain. CONCLUSION: The pain willingness factor of acceptance and catastrophizing both appear to be strong predictors for self-reported pain interference. During an objective assessment of pain interference, however, pain willingness shows a stronger effect and attenuates the negative impact of catastrophizing on task functioning.

Consensus guidelines for the selection and implantation of patients with noncancer pain for intrathecal drug delivery.

Intrathecal therapy offers an invasive alternative for the long-term management of select patients with intractable pain associated with various disease states, including those of noncancer origin. It is commonly accepted that proper patient selection is essential to optimizing treatment outcomes, yet the practice of candidate selection for device implantation varies widely. A multifaceted approach--with consideration of preexisting medical comorbidities; psychological status; associated social, technical, and economic issues; and response to intrathecal trialing--enables practitioners to fully evaluate the appropriateness of implanting a patient with an intrathecal drug delivery system. Yet, to date no standard set of guidelines have been developed to aid practitioners in navigating this evaluation process. Using experience- and knowledge-based expert opinion to systematically evaluate the available evidence, this article provides consensus guidelines aimed at optimizing the selection of patients with noncancer pain for intrathecal therapy. In conclusion, complete assessment of a patient's physical, psychological, and social characteristics, can guide practitioners in determining the appropriateness of initiating intrathecal therapy. These consensus guidelines are intended to assist with weighing this risk/benefit ratio of intrathecal therapy, thereby minimizing the potential for treatment failure, unacceptable adverse effects, and excess mortality.

Depressive symptoms and pain evaluations among persons with chronic pain: catastrophizing, but not pain acceptance, shows significant effects.

Cognitive factors such as catastrophic thoughts regarding pain, and conversely, one's acceptance of that pain, may affect emotional functioning among persons with chronic pain conditions. The aims of the present study were to examine the effects of both catastrophizing and acceptance on affective ratings of experimentally induced ischemic pain and also self-reports of depressive symptoms. Sixty-seven individuals with chronic back pain completed self-report measures of catastrophizing, acceptance, and depressive symptoms. In addition, participants underwent an ischemic pain induction procedure and were asked to rate the induced pain. Catastrophizing showed significant effects on sensory and intensity but not affective ratings of the induced pain. Acceptance did not show any significant associations, when catastrophizing was also in the model, with any form of ratings of the induced pain. Catastrophizing, but not acceptance, was also significantly associated with self-reported depressive symptoms when these two variables were both included in a regression model. Overall, results indicate negative thought patterns such as catastrophizing appear to be more closely related to outcomes of perceived pain severity and affect in persons with chronic pain exposed to an experimental laboratory pain stimulus than does more positive patterns as reflected in measures of acceptance.

Multidimensional Outcomes Analysis of Intrathecal, Oral Opioid, and Behavioral-Functional Restoration Therapy for Failed Back Surgery Syndrome: A Retrospective Study With 4 Years' Follow-up.

Study Design. A retrospective design comparing three matched groups was used to evaluate the application of a multidimensional approach to outcomes analysis using a variety of disease-specific and generic outcome measures to assess three treatments for failed back surgery syndrome. Objective. The objective of this study was to explore the use of a multidimensional analysis of outcomes to compare and contrast the effects of three different treatments: 1) intrathecal therapy using an implantable drug administration system (DAS), 2) standard medical therapy emphasizing the use of oral opioids (OO), and 3) residential pain and rehabilitation program (RPRP) for the treatment of chronic low back pain. Summary of Background Data. The incidence of low back pain in patients with prior back surgery remains significant. Treatments for failed back surgery syndrome include interventional, pharmacologic, and functional restorative therapies. Outcome studies have rarely compared these three treatments over an extended follow-up period using both disease-specific and generic outcome measures. This study examined three groups of patients completing treatment in clinical setting with a 4-year follow-up. Methods. Patients were selected from three different clinical treatment populations: DAS, OO, and RPRP. The three groups consisted of 40-50 patients each, matched on a number of demographic and pain variables. The average duration of follow-up for each group was about 4 years. Data were collected on disease-specific outcome variables using Numerical Pain Ratings, the McGill Pain Questionnaire, the Beck Depression Inventory, the Oswestry Disability Scale, medication utilization, and other generic outcomes such as SF-36, Quality of Well-Being, Overall Improvement in Pain, and Patient Satisfaction. Information was obtained via chart review and telephone interviews with patients by a disinterested third party. Analysis of variance, chi-square test, and t-test were performed on the various dependent measures. Results. The DAS group appeared to be superior to the OO and RPRP groups on 8 of 11 dependent measures, but only one dependent measure, the posttreatment numerical pain rating, was statistically significant. The RPRP group reported the highest Quality of Well-Being score, while the OO group had the highest level of patient satisfaction. Overall, each of the groups fell well below the "normal" range on generic measures, even when compared to other clinical populations. Measures of depression, subjective disability, and pain remained in the "moderate" range with little evidence of improved functioning or quality of life (QoL). Despite these findings, patients rated their overall improvement at 50-60% and reported high levels of satisfaction with their treatment. Conclusions. The interpretation as to the most effective treatment depended on the particular outcome measure emphasized. There appeared to be a "disconnect" between ratings of pain, disability, mood, and QoL. The use of a multidimensional outcomes approach revealed a number of inconsistencies in the data, which could have been overlooked using only pain ratings and patient satisfaction data. No one treatment emerged as the most effective across all of the disease-specific and generic measures. However, patients in the DAS group tended to report greater improvement. Overall, although generally "satisfied" with treatment, they were generally "satisfied" with treatment despite continuing to report significant levels of pain, disability, and impaired QoL.