Changes in Pain Sensitivity and Pain Modulation During Oral Opioid Treatment: The Impact of Negative Affect.

OBJECTIVE: Opioids are frequently prescribed for chronic low back pain (CLBP), but there are broad individual differences in the benefits and risks of opioid therapy, including the development opioid-induced hyperalgesia. This study examined quantitative sensory testing (QST) data among a group of CLBP patients undergoing sustained oral opioid treatment. We investigated whether individual differences in psychological characteristics were related to opioid-induced changes in pain perception and pain modulation. DESIGN: The six-month, open-label trial evaluated patients with low to high levels of negative affect (e.g., symptoms of distress, depression and anxiety); participants underwent QST at baseline (prior to initiating treatment) and during oral opioid treatment. SETTING: A chronic pain management center. PATIENTS: The 31 study participants had chronic discogenic back pain, with a pain intensity rating >3/10. Participants were divided into groups with high vs. low levels of Negative Affect (NA). RESULTS: In the previously-published manuscript describing the clinical outcomes of the trial, high NA patients achieved only about half of the analgesic effect observed in the low NA group (Wasan AD, Michna E, Edwards RR, et al. Psychiatric comorbidity is associated prospectively with diminished opioid analgesia and increased opioid misuse in patients with chronic low back pain. Anesthesiology 2015;123:861-72). The QST findings reported here suggested that tolerance to experimental (cold pressor) pain and conditioned pain modulation tended to decrease in the high NA group over the course of opioid treatment, while temporal summation of mechanical pain declined in the low NA group. CONCLUSIONS: These results reveal that while the low NA group seemed to exhibit a generally adaptive, analgesic pattern of changes during opioid management, the high NA group showed a pattern more consistent with opioid-induced hyperalgesic processes. A greater susceptibility to hyperalgesia-promoting changes in pain modulation among patients with high levels of distress may contribute to a lower degree of benefit from opioid treatment in high NA patients.

Catastrophic thinking and increased risk for prescription opioid misuse in patients with chronic pain.

BACKGROUND: As a consequence of the substantial rise in the prescription of opioids for the treatment of chronic noncancer pain, greater attention has been paid to the factors that may be associated with an increased risk for prescription opioid misuse. Recently, a growing number of studies have shown that patients with high levels of catastrophizing are at increased risk for prescription opioid misuse. OBJECTIVE: The primary objective of this study was to examine the variables that might underlie the association between catastrophizing and risk for prescription opioid misuse in patients with chronic pain. METHODS: Patients with chronic musculoskeletal pain (n=115) were asked to complete the SOAPP-R, a validated self-report questionnaire designed to identify patients at risk for prescription opioid misuse. Patients were also asked to complete self-report measures of pain intensity, catastrophizing, anxiety, and depression. RESULTS: Consistent with previous research, we found that catastrophizing was associated with an increased risk for prescription opioid misuse. Results also revealed that the association between catastrophizing and risk for opioid misuse was partially mediated by patients' levels of anxiety. Follow-up analyses, however, indicated that catastrophizing remained a significant 'unique' predictor of risk for opioid misuse even when controlling for patients' levels of pain severity, anxiety and depressive symptoms. DISCUSSION: Discussion addresses the factors that might place patients with high levels of catastrophizing at increased risk for prescription opioid misuse. The implications of our findings for the management of patients considered for opioid therapy are also discussed.

Maternal satisfaction and pain control in women electing natural childbirth.

BACKGROUND AND OBJECTIVES: Many women who choose natural childbirth for labor ultimately request epidural analgesia to control labor pain. Unfortunately, parturients and family members may often be unprepared for epidural anesthesia, which can contribute to disappointment and dissatisfaction with their labor and delivery. This study examines how epidural analgesia for labor influences maternal satisfaction in women who initially choose natural childbirth. METHODS: This study compared pain and maternal satisfaction in women who elected natural childbirth and successfully followed through (n = 23), with those who elected natural childbirth, but requested epidural analgesia during their labor (n = 24). Subjects rated their pain throughout labor and completed pre- and postlabor questionnaires. RESULTS: Women who requested epidural analgesia for pain during labor reported significantly lower pain scores than those women who had natural childbirth (P < .001). However, 88% of women who requested an epidural for pain reported being less satisfied with their childbirth experience than those who did not, despite lower pain intensity. Antenatal survey results suggest that concerns about epidurals and their effect on the baby, greater than anticipated labor pain, perceived failure of requesting an epidural, and longer duration of labor may have accounted for these findings. CONCLUSIONS: This study examined the influence of epidural analgesia in parturients electing natural childbirth. Pain relief alone was not found to improve maternal satisfaction. This study highlights the importance of experience and prelabor expectations on maternal satisfaction with childbirth.

Interactive computer method for rating quality of life: comparison of chronic pain patients and healthy controls.

OBJECTIVE: This study presents information on the development of an interactive computer-based rating method of quality of life that assesses the multidimensional impact of chronic pain on the individual. METHOD: A software program assessing 20 categories of quality of life was created and administered to 103 chronic pain patients. Comparison data were obtained from 103 matched healthy controls. RESULTS: High variability was found among pain patients in their ratings of quality of life, and pain patients rated all categories lower than controls. Three groups emerged from a cluster analysis of the data reflecting high, mixed, and low ratings of satisfaction with quality of life. CONCLUSIONS: The rating method was convenient, was easy for the patient to understand, and took very little time to administer. Further investigation of the validity and reliability of this tool is needed.

Perceived treatment helpfulness and cost in chronic pain rehabilitation.

OBJECTIVE: This article examines the perceived helpfulness of treatment components in comprehensive interdisciplinary pain management programs as they relate to cost. DESIGN: Patient satisfaction results assessed by the Treatment Helpfulness Questionnaire (THQ) and treatment costs were compared for 309 subjects at three comprehensive interdisciplinary chronic pain management centers. All subjects completed the THQ immediately after treatment, and follow-up data were gathered 3 to 6 months after the end of treatment at two of the three centers. RESULTS: Ratings of treatment helpfulness were not found to be related to either demographic or medical variables. Mean THQ ratings for many treatment modalities did differ significantly between centers, but subjects at all centers generally gave higher THQ ratings to psychological and educational therapies than to physical therapy and medical modalities both at posttreatment and at follow-up evaluations. More costly treatments generally did not receive higher ratings than less costly ones. THQ ratings tended to decline modestly from posttreatment to follow-up evaluations. CONCLUSIONS: For the selected population of patients undergoing comprehensive interdisciplinary pain management, educational and psychological approaches received high ratings of helpfulness at a relatively low cost. Further research is needed to address whether comparative patient satisfaction data can be used at pain centers to produce improved outcomes at reduced costs.

Characteristics of methadone maintenance patients with chronic pain.

Chronic pain patients who have limited access to opioids may be redirected to methadone maintenance centers for management of their pain. Unfortunately, little information exists on the incidence and characteristics of methadone maintenance patients with chronic pain. The aim of this study was to survey individuals at methadone maintenance centers in order to determine the prevalence of chronic pain and to explore differences between patients with and without pain in this treatment setting. Of 248 participants interviewed at three centers, 152 (61.3%) reported chronic pain. Compared with patients without pain, those with pain reported significantly more health problems (P < 0.001), more psychiatric disturbance (P < 0.05), more prescription and nonprescription medication use (P < 0.001), and greater belief that they were undertreated (P < 0.001); 44% of those with pain believed that opioids prescribed for their pain had led to an addiction problem. Most of the methadone maintenance patients stated that they had always required some substance (alcohol or opioids) to feel normal. These results raise many questions about chronic-pain treatment policies and resources for persons with a history of substance abuse. Further investigations are needed to define the needs of this population and to improve their access to effective pain management.

Opioid therapy for chronic noncancer back pain. A randomized prospective study.

STUDY DESIGN: A randomized, open, long-term, repeated-dose comparison of an anti-inflammatory drug and two opioid regimens in 36 patients with back pain. OBJECTIVES: To examine the long-term safety and efficacy of chronic opioid therapy in a randomized trial of patients with back pain. METHODS: All participants underwent a 4-week washout period of no opioid medication before being randomly assigned to one of three treatment regimens for 16 weeks: 1) naproxen only, 2) set-dose oxycodone, or 3) titrated-dose oxycodone and sustained-release morphine sulfate. All patients then were assigned to a titrated dose of opioids for 16 weeks and then gradually tapered off their medication for 12 weeks. Finally, all participants were monitored for a 1-month posttreatment washout period. Each patient was called once a week for a report on pain, activity, mood, medication, hours awake, and adverse effects and was monitored carefully for signs of abuse and noncompliance. RESULTS: Weekly reports during the experimental phase showed the titrated-dose group to have less pain (P < 0.001) and less emotional distress (P < 0.001) than the other two groups. Both opioid groups were significantly different from the naproxen-only group. During the titration phase, patients also reported significantly less pain and improved mood. Few differences were found in activity or hours asleep, or between average pretreatment and posttreatment phone-interview and questionnaire variables. No adverse events occurred, and only one participant showed signs of abuse behavior. CONCLUSIONS: The results suggest that opioid therapy has a positive effect on pain and mood but little effect on activity and sleep. Opioid therapy for chronic back pain was used without significant risk of abuse. However, tapered-off opioid treatment is palliative and without long-term benefit.

Effects of epidural steroid injection on pain due to lumbar spinal stenosis or herniated disks: a prospective study.

OBJECTIVES: To describe the extent of pain relief two weeks after an epidural steroid injection in patients with herniated disks and lumbar spinal stenosis, and to identify predictors of changes in pain ratings in each population. METHODS: The study design was a prospective evaluation of patients with lumbar spinal stenosis (LSS) and herniated disks (HDs) referred to a hospital-based pain clinic for an epidural steroid injection (ESI). A complete history, detailed physical examination, comprehensive pain questionnaire, and Brief Symptom Inventory were obtained for all patients. Pain was assessed at baseline and two weeks following a single ESI using a visual analog scale. RESULTS: Two hundred twelve patients (mean age 54 years) were enrolled, and 78 of these provided pain ratings before and two weeks after the injection. LSS patients improved less two weeks following the ESI than HD patients (P = 0.04). Just 38% of LSS patients reported improvement in pain score compared with 61% of HD patients. In analyses that combined LSS and HD patients, predictors of worse response included a report of health problems and a diagnosis of LSS. CONCLUSIONS: LSS patients have worse response to ESIs than HD patients. The poor response to ESI in patients with LSS underscores the need for randomized controlled trials of ESI in this population.

Controlled trial of Japanese acupuncture for chronic myofascial neck pain: assessment of specific and nonspecific effects of treatment.

OBJECTIVE: This article examines the specific and nonspecific effects of Japanese acupuncture on chronic myofascial neck pain in a randomized single-blind trial. DESIGN: Forty-six patients were randomly assigned to receive relevant acupuncture, irrelevant acupuncture, or no-acupuncture control treatment consisting of nonsteroidal anti-inflammatory medication. The two acupuncture groups underwent comparable light shallow needling. The irrelevant acupuncture group received acupuncture at specific sites not relevant for cervical pain. OUTCOME MEASURES: The study measures included the McGill Pain Questionnaire-Short Form (SF-MPQ), the Short-Form Health Survey (SF-36), the Symptom Checklist 90-Revised (SCL-90-R), medication diary, and physiologic measures. The factors examined as predictors of outcome pain ratings were experience with, beliefs about, and knowledge of acupuncture before treatment; perceived efficacy, credibility, and logic of acupuncture; perceived competence of the acupuncturist; and painfulness of acupuncture. RESULTS: No differences were found among the three groups at baseline, except that the relevant acupuncture group reported having had more previous acupuncture treatments. No significant differences in terms of perceived credibility or perceived effectiveness of treatment were found between the two acupuncture groups. The relevant acupuncture group had significantly greater pre-/posttreatment differences in pain than the irrelevant acupuncture and control groups (p < .05). The nonspecific effects of confidence in the acupuncturist, willingness to try any treatment, mood, and physiologic effect of needling were not predictive of treatment outcome, whereas confidence in the treatment and past experiences with acupuncture did correlate significantly with a decrease in pain. CONCLUSIONS: Relevant acupuncture with heat contributes to modest pain reduction in persons with myofascial neck pain. Previous experience with and confidence in treatment help to predict benefit. Measurement of nonspecific effects of alternative therapy is recommended in future clinical trials.

Assessment of postoperative pain management: patient satisfaction and perceived helpfulness.

OBJECTIVE: Increasing attention has been given to the assessment of patient satisfaction as a way to monitor quality of care in hospital settings. Postoperative patient satisfaction has been thought to be related to level of pain intensity, expectations of outcome, perceived concern by the staff, and helpfulness of treatments. The aim of this study is to develop a simple, reliable measure to assess pain and satisfaction in postsurgical patients and to examine factors related to patient satisfaction. DESIGN: A satisfaction questionnaire was developed for this study and administered to 119 patients who had undergone a major orthopedic surgical procedure. The majority of the patients were diagnosed with osteoarthritis and reported moderate to severe preoperative pain. The 13-item measure was found to be reliable (test-retest r = .86; interexaminer r = .98), valid (exploratory factor analyses; intercorrelations), and easy to administer. RESULTS: Results showed that the majority of the patients were satisfied with their care (91%), postoperative pain intensity (94%), and the way they were treated by the physicians and nurses (98%). Patients with low postoperative pain ratings who perceived that the physicians and nurses showed concern with how much pain they were feeling reported greatest satisfaction with their care (p < .001). In general, lower postoperative pain ratings were the best predictors of satisfaction and helpfulness of treatment. Preoperative pain status, expected level of postoperative pain, and time waiting for pain medication after a request was made were not significantly correlated with ratings of postoperative pain or satisfaction. CONCLUSIONS: These results highlight the important influence of adequate treatment of postoperative pain and perceived concern by the hospital staff on patient satisfaction.

Readiness to adopt a self-management approach to chronic pain: the Pain Stages of Change Questionnaire (PSOCQ).

This manuscript describes the development and initial validation of a self-report questionnaire designed to assess an individual's readiness to adopt a self-management approach to their chronic pain condition. Theory and preliminary empirical work informed the development of a pool of items that were administered to a sample of individuals reporting chronic pain. Analyses of the data support a four factor measure that is consistent with the transtheoretical model of change and associated stages of change model. Each of the four factors, precontemplation, contemplation, action, and maintenance, was found to be internally consistent and stable over time. There was also substantial support for each factor's discriminant and criterion-related validity.

Treatment Helpfulness Questionnaire: a measure of patient satisfaction with treatment modalities provided in chronic pain management programs.

The Treatment Helpfulness Questionnaire (THQ) is presented as a reliable and valid measure for assessing patient perceptions of the helpfulness of treatment modalities offered at multidisciplinary pain centers. It is easy to administer and score and shows good interscorer and test-retest reliability without order effects and with good internal consistency. Patients give diverse responses to items that fall into four factors, three of which represent identifiable components of multidisciplinary treatment for chronic pain. Findings that similar THQ items are positively correlated and that many items show positive correlations with treatment outcome support the validity of the instrument. The latter finding also suggests the potential of patient satisfaction measurement for improving treatment outcomes at pain centers.

Comprehensive pretreatment and outcome assessment for chronic opioid therapy in nonmalignant pain.

Guidelines currently exist on the use of opioid therapy for chronic nonmalignant pain. Unfortunately, no randomized, prospective, controlled studies have been conducted to verify these guidelines or determine the optimal inclusion or exclusion criteria for this treatment. The decision to administer opioid therapy is often based on treatment orientation and subjective clinical impressions. This article contains two sections relevant to assessment for chronic opioid therapy in nonmalignant pain. First, a brief review of the literature on opioid therapy is presented. Survey data on opioid use and follow-up helpfulness are also presented. Second, current guidelines for opioid therapy are discussed, and areas considered critical in assessing treatment efficacy are reviewed, including (1) pain intensity, (2) functional capacity, (3) personality and mood, (4) pain beliefs, (5) medication usage, (6) adverse effects, (7) health-care utilization, and (8) medical and psychosocial history. Finally, questions are posed for future investigations of the efficacy of opioid therapy in selected patients with chronic nonmalignant pain. This article identifies important areas to consider when initiating controlled trials designed to identify those patients most suitable for chronic use of opioids.

Psychological factors in chronic pain: assessment and treatment issues.

This article presents an overview of psychological factors which influence chronic pain. Emphasis is placed on assessment techniques and psychological treatment approaches for patients with chronic pain. In the first section, the usefulness of psychometric measures are discussed and areas considered critical in the psychological assessment of chronic pain are reviewed, including (1) pain intensity, (2) functional capacity, (3) mood and personality, (4) pain beliefs and coping, (5) medication usage, (6) adverse effects, (7) behavioral analysis, and (8) health care utilization. Personality factors affecting pain syndromes, DSM-IV diagnoses and health care utilization issues are also discussed. In the second section, an overview of psychological and behavioral interventions for chronic non-malignant pain are presented within the context of a multi-disciplinary pain management program. A rationale for a group-based program along with roles of a team, program goals, patient selection criterion, components of the program, and information on program evaluation is reviewed.

Survey of opioid use in chronic nonmalignant pain patients.

BACKGROUND AND OBJECTIVES: Opioids have been accepted as appropriate treatment for acute and cancer pain, but remain controversial for use with chronic nonmalignant pain. Clinicians are concerned about efficacy, tolerance, addiction, and unwanted side effects. METHODS: The aim of this study was to survey chronic pain patients who were taking opioids for their pain, to determine the incidence of these adverse conditions. Two hundred seventeen patients who were being treated for their pain at two different pain centers completed a medication questionnaire. The most common diagnosis was low back pain. One hundred twelve patients reported taking oral opioids for their pain. RESULTS: Of the patients who reported taking opioids for their chronic pain, 83% felt that the opioids were moderately beneficial in relieving their pain; 25% felt that the opioid had not lost its ability to relieve the pain over time; 35% reported that they did not need to increase their medication; 36% expressed no fear of addiction or dependence; and 56% reported having no unwanted side effects. CONCLUSIONS: The results suggest that chronic nonmalignant pain patients taking opioids for their pain reported some tolerance, fear of addiction, and side effects when taking opioids. However, despite these concerns, some of these patients felt that opioid therapy was very beneficial. Further investigations are needed to determine which patient characteristics predict benefit from opioid therapy for nonmalignant pain.

Psychosocial and pharmacologic predictors of satisfaction with intravenous patient-controlled analgesia.

Despite intravenous patient-controlled analgesia's (IV-PCA) increasing popularity, the psychological and pharmacological factors upon which patient satisfaction with IV-PCA are based are unknown. Sixty-eight women scheduled for abdominal hysterectomy completed a series of questionnaires measuring emotional distress, locus of control, perceived support, and optimism before their surgery. Postoperative ratings of pain intensity, emotional distress, anticipated recovery time, nightmares, and satisfaction with IV-PCA were taken 1 and 3 days after surgery. A nurse observer rated perceived anxiety, estimated recovery, and satisfaction with IV-PCA. Cumulative and hourly IV-PCA use and dose/demand ratio were obtained. Degree of dissatisfaction with IV-PCA was significantly correlated with pain intensity, nightmares, patient's perceptions of support, expectations of recovery, preoperative anxiety, and postoperative depression. Dose/demand ratio and hourly analgesic usage were significantly related to pre- and postoperative emotional distress factors. Perioperative management of anxiety, perceptions, and expectations may prove valuable in improving pain control and satisfaction with IV-PCA.

Illness behavior in children of chronic pain patients.

OBJECTIVE: Recent studies on pain behavior have pointed to a relationship between expression of illness in patients with chronic pain and reports of physical complaints in other family members. This article includes two related studies. The aim of the first study was to determine whether, among pain patient families, parents who exhibited higher levels of illness behavior and emotional distress were more likely to report that their children had frequent pain complaints. The aim of the second study was to assess whether children of patients with chronic pain were perceived by their parents to have more pain and illness behavior than children of non-pain parents. METHOD: In the first study, forty-two primary caregivers in families with a parent with chronic pain completed questionnaires regarding their children's pain and illness behavior. In the second study, report of somatic complaints in children of chronic pain parents was compared to complaints in fifty-five children of parents without chronic pain. RESULTS: Results of the first study showed that frequently reported pain in the child was associated with significantly higher levels of parent disability, pain behavior and emotional distress. Results of the second study showed that children of patients with chronic pain were reported to have more frequent abdominal pain and to use more medication than children of parents without pain. CONCLUSIONS: The findings of these studies suggest that children of parents with chronic pain may be at risk for illness behavior, especially when the parents exhibit emotional reactions to their pain.

Low back pain patients unresponsive to an epidural steroid injection: identifying predictive factors.

This study examined factors that help to identify low back pain patients who do not benefit from a lumbar epidural steroid injection (LESI). Two-hundred and forty-nine chronic low back pain patients assessed their pain intensity before, 1 day after, and 2 weeks after receiving a LESI. All patients completed a comprehensive pain questionnaire and a Brief Symptom Inventory (BSI) prior to treatment. Diagnosis and extent of pathology were independently assessed by two physicians. One-hundred and thirty-one patients (52.6%) were followed 1 year after treatment. Results showed that average pain intensity ratings decreased in 62.3% of patients 2 weeks after receiving a LESI. One year after treatment, 62.6% felt that LESI was helpful. Nine patients (7%) felt that the treatment was harmful. Four factors were identified that best predicted poor outcome 2 weeks after LESI: (a) greater number of previous treatments for pain; (b) more medications taken; (c) pain not necessarily increased by activities, and (d) pain increased by coughing. Factors that predicted no benefit 1 year after treatment included (a) pain does not interfere with activities; (b) unemployment due to pain; (c) normal straight-leg raise test prior to treatment; and (d) pain not decreased by medication.

The relationship between cigarette smoking and chronic low back pain.

This study investigated the extent to which habitual cigarette smoking relates to physical and psychological indices of chronic pain. From a review of patient records, 54% of back pain patients referred for treatment of their pain admitted to smoking cigarettes. Response from a smoking questionnaire showed that 57% of the patients who smoked reported having a need to smoke when they were in pain. Most patients (91%), however, believed that smoking had no effect on their pain intensity. When smoking and nonsmoking back pain patients were compared, the smokers showed significantly higher levels of emotional distress, they tended to remain inactive, and they relied on medication more often than the nonsmoking patients. The results further suggest that pain patients are at risk for increasing smoking behavior when they are experiencing periods of heightened pain intensity.

Effects of significant weight gain on chronic pain patients.

This study examined the effect of significant weight gain on physical, demographic, behavioral, and psychosocial factors in a representative sample of chronic pain patients. One hundred fifty-five chronic pain patients who reported gaining more than 15 pounds since the onset of their pain were compared with 341 pain patients who stated that their weight had remained the same since the onset of their pain. All patients were given a medical examination and each patient completed a comprehensive pain questionnaire and an SCL-90. Results showed that a significant relationship exists between weight gain and decreased physical activity, increased emotional distress, and accident liability. This study suggests that the inclusion of weight management training in multidisciplinary pain centers may play an important part in the rehabilitation of chronic pain patients.