W. Michael Hooten

Smoking and pain: pathophysiology and clinical implications.

Cigarette smoke, which serves as a nicotine delivery vehicle in humans, produces profound changes in physiology. Experimental studies suggest that nicotine has analgesic properties. However, epidemiologic evidence shows that smoking is a risk factor for chronic pain. The complex relationship between smoking and pain not only is of scientific interest, but also has clinical relevance in the practice of anesthesiology and pain medicine. This review will examine current knowledge regarding how acute and chronic exposure to nicotine and cigarette smoke affects acute and chronic painful conditions. It will cover the relevant pharmacology of nicotine and other ligands at the nicotinic acetylcholine receptor as related to pain, explore the association of cigarette smoking with chronic painful conditions and potential mechanisms to explain this association, and examine clinical implications for the care of smokers with pain.

A longitudinal study of the efficacy of a comprehensive pain rehabilitation program with opioid withdrawal: Comparison of treatment outcomes based on opioid use status at admission

Abstract Use of opioids for chronic non‐cancer pain is controversial and the efficacy of comprehensive pain rehabilitation programs (CPRPs) that incorporate opioid withdrawal requires further investigation. We test the hypothesis that patients with chronic pain and longstanding opioid use who undergo opioid withdrawal in the course of rehabilitative treatment will experience significant and sustained improvement in pain and functioning similar to patients who were not taking opioids. A longitudinal design study compared 373 consecutive patients admitted to the Mayo Clinic Pain Rehabilitation Center at admission, discharge and six‐month posttreatment by opioid status at admission. Measures of pain severity, depression, psychosocial functioning, health status, and pain catastrophizing were used to assess between‐ and within‐group differences. Treatment involved a 3‐week interdisciplinary pain rehabilitation program focused on functional restoration. Over one‐half of patients (57.1%) were taking opioids daily at admission. The majority of patients (91%) completed rehabilitation and 70% of patients who completed the program returned questionnaires six months posttreatment. On admission, patients taking low‐ and high‐dose opioids reported significantly greater pain severity (P = .001) and depression (P = .001) than the non‐opioid group. Significant improvement was found on all outcome variables following treatment (P < .001) and six‐month posttreatment (P < .001) regardless of opioid status at admission. There were no differences between the opioid and non‐opioid groups upon discharge from the program or at six months following treatment. Conclusion: Patients with longstanding CPRP on chronic opioid therapy, who choose to participate in interdisciplinary rehabilitation that incorporates opioid withdrawal, can experience significant and sustained improvement in pain severity and functioning.

Epidural Abscess and Meningitis After Epidural Corticosteroid Injection

Epidural abscess with and without associated meningitis after epidural corticosteroid injections for radicular back pain is a rarely reported complication. We report the occurrence of an epidural abscess and meningitis in a 70-year-old man after 2 epidural corticosteroid injections for treatment of acute radicular lumbar back pain. At the time of diagnosis, cerebrospinal fluid cultures grew Staphylococcus aureus, and the patient was treated with intravenous antibiotics. Possible predisposing factors for the development of an epidural abscess and meningitis in this patient include a 2-year history of neutropenia and an accidental dural puncture that occurred during performance of the first epidural injection. A literature search identified 11 reported cases of epidural abscess, 2 of epidural abscess and meningitis, and 1 of meningitis attributed to epidural corticosteroid injections. Eight of the 14 reported patients were immunocompromised, and 8 (67%) of the 12 in whom cultures of blood, cerebrospinal fluid, or epidural pus were performed had results positive for S. aureus. Antibiotic prophylaxis for S. aureus should be considered for immunocompromised patients undergoing epidural corticosteroid injections.

Prevalence and Clinical Correlates of Vitamin D Inadequacy among Patients with Chronic Pain

OBJECTIVE Vitamin D inadequacy is associated with medication refractory musculoskeletal pain and neuromuscular dysfunction. This vitamin deficiency could subsist as an unrecognized comorbid condition among patients with chronic pain. The primary objective of this study was to determine the prevalence and clinical correlates of vitamin D inadequacy in patients seeking treatment for chronic pain. DESIGN Retrospective case series. SETTING Multidisciplinary pain rehabilitation center at a tertiary referral medical center. PATIENTS The study involved 267 chronic pain patients admitted from February to December 2006. INTERVENTION Serum 25-hydroxyvitamin D (25[OH]D) was drawn at admission. OUTCOME MEASURES Patients with serum 25[OH]D levels < or=20 ng/mL were considered to have inadequate levels and those with levels >20 ng/mL were considered to have adequate levels. Upon admission, opioid intake was documented and patients completed the Short Form-36 Health Status Questionnaire. RESULTS The prevalence of vitamin D inadequacy was 26% (95% confidence interval, 20.6-31.1%). Among patients using opioids, the mean morphine equivalent dose for the inadequate vitamin D group was 133.5 mg/day compared with 70.0 mg/day for the adequate group (P = 0.001). The mean duration of opioid use for the inadequate and adequate groups were 71.1 months and 43.8 months, respectively (P = 0.023). Opioid users with inadequate levels reported worse physical functioning (P = 0.041) and health perception (P = 0.003) than opioid users with adequate levels. CONCLUSION The prevalence and clinical correlates identified in this pilot study provide the basis for the assertion that vitamin D inadequacy may represent an under-recognized source of nociception and impaired neuromuscular functioning among patients with chronic pain.

Effects of strength vs aerobic exercise on pain severity in adults with fibromyalgia: a randomized equivalence trial.

Summary Strengthening and aerobic exercise had equivalent effects on reducing pain severity in patients with fibromyalgia. Abstract Strength training and aerobic exercise have beneficial effects on pain in adults with fibromyalgia. However, the equivalence of strengthening and aerobic exercise has not been reported. The primary aim of this randomized equivalence trial involving patients with fibromyalgia admitted to an interdisciplinary pain treatment program was to test the hypothesis that strengthening (n = 36) and aerobic (n = 36) exercise have equivalent effects (95% confidence interval within an equivalence margin ±8) on pain, as measured by the pain severity subscale of the Multidimensional Pain Inventory. Secondary aims included determining the effects of strengthening and aerobic exercise on peak Vo2 uptake, leg strength, and pressure pain thresholds. In an intent‐to‐treat analysis, the mean (± standard deviation) pain severity scores for the strength and aerobic groups at study completion were 34.4 ± 11.5 and 37.6 ± 11.9, respectively. The group difference was −3.2 (95% confidence interval, −8.7 to 2.3), which was within the equivalence margin of Δ8. Significant improvements in pain severity (P < .001), peak Vo2 (P < .001), strength (P < .001), and pain thresholds (P < .001) were observed from baseline to week 3 in the intent‐to‐treat analysis; however, patients in the aerobic group (mean change 2.0 ± 2.6 mL/kg/min) experienced greater gains (P < .013) in peak Vo2 compared to the strength group (mean change 0.4 ± 2.6 mL/kg/min). Knowledge of the equivalence and physiological effects of exercise have important clinical implications that could allow practitioners to target exercise recommendations on the basis of comorbid medical conditions or patient preference for a particular type of exercise. This study found that strength and aerobic exercise had equivalent effects on reducing pain severity among patients with fibromyalgia.

The Effects of Depression and Smoking on Pain Severity and Opioid Use in Patients with Chronic Pain

&NA; Depression and smoking are common comorbid conditions among adults with chronic pain. The aim of this study was to determine the independent effects of depression on clinical pain and opioid use among patients with chronic pain according to smoking status. A retrospective design was used to assess baseline levels of depression, clinical pain, opioid dose (calculated as morphine equivalents), and smoking status in a consecutive series of patients admitted to a 3‐week outpatient pain treatment program from September 2003 through February 2007. Depression was assessed using the Centers for Epidemiologic Studies‐Depression scale, and clinical pain was assessed using the pain severity subscale of the Multidimensional Pain Inventory. The study cohort (n = 1241) included 313 current smokers, 294 former smokers, and 634 never smokers. Baseline depression (P = .001) and clinical pain (P = .001) were greater among current smokers compared to former and never smokers, and the daily morphine equivalent dose was greater among smokers compared to never smokers (P = .005). In multivariate linear regression analyses, baseline pain severity was independently associated with greater levels of depression, but not with smoking status. However, status as a current smoker was independently associated with greater opioid use (by 27 mg/d), independent of depression scores. The relationship between depression, smoking status, opioid use, and chronic pain is complex, and both depression and smoking status may be potentially important considerations in the treatment of patients with chronic pain who utilize opioids. This study found that pain severity was associated with greater depression but not smoking; however, smoking was associated with greater opioid use, independent of depression.

The Effects of Smoking Status on Opioid Tapering Among Patients with Chronic Pain

OBJECTIVE: The primary aim of this study was to determine if smoking status affected the ability of patients with chronic pain to reduce opioid consumption during a 3-wk pain rehabilitation program. Secondary aims included determining the associations between smoking status, admission opioid use, and pain severity. METHODS: We used a retrospective, repeated measures design to assess pre- and post-treatment outcomes in a consecutive series of patients admitted to a 3-wk, outpatient pain treatment program from September 2003 through February 2007. Outcome measures included the frequency of successful opioid tapering, pain severity subscale of the Multidisciplinary Pain Inventory, and program completion status. RESULTS: The study cohort included 1241 patients (women 928); 313 (25%) smokers, 294 (24%) former smokers, and 634 (51%) never smokers. There were more smokers using opioids at admission (P < 0.001) compared to former and never smokers. Likewise, the mean morphine equivalent dose (P = 0.013) and pain severity scores (P < 0.001) of smokers were higher compared to former and never smokers. The success of opioid tapering did not depend on smoking status, and all groups experienced significant reductions in pain severity at program completion (P < 0.001). However, a higher proportion of smokers did not complete treatment (P < 0.001). CONCLUSIONS: For patients completing a pain rehabilitation program, most were able to eliminate opioid use, regardless of smoking status. However, significantly more smokers did not complete treatment. The most frequent reasons for program noncompletion included discrepant expectations of treatment, acute illness, and psychosocial stressors.

Preoperative Gabapentin for Acute Post-thoracotomy Analgesia: A Randomized, Double-Blinded, Active Placebo-Controlled Study

Background:  The role of preoperative gabapentin in postoperative pain management is not clear, particularly in patients receiving regional blockade. Patients undergoing thoracotomy benefit from epidural analgesia but still may experience significant postoperative pain. We examined the effect of preoperative gabapentin in thoracotomy patients.

Impact of tobacco use in patients presenting to a multidisciplinary outpatient treatment program for fibromyalgia.

Objectives This study examined the relationship between the severity of fibromyalgia symptoms and current tobacco use in patients evaluated at a specialized fibromyalgia treatment program. Methods Demographic and clinical data from 984 consecutive patients evaluated at the Mayo Clinic Fibromyalgia Treatment Program including the Fibromyalgia Impact Questionnaire (FIQ) were prospectively collected and stored in an electronic medical record and an electronic database. Univariate analyses were performed comparing tobacco users and nonusers. A post-hoc analysis of covariance was conducted for tobacco use, using group differences of confounding clinical and demographic variables. A P value ≤ 0.05 was accepted as the level of significance. Results One hundred and forty-five patients were identified as tobacco users (14.7%). Tobacco use was associated with greater pain intensity as measured by pain scales and the pain component of the FIQ. Tobacco users had a greater FIQ composite score 70.0(15.1) versus 61.8(16.8), P<0.001. By univariate analysis, tobacco users had higher scores on all the FIQ components and fewer good days and more days of work missed per week. Tobacco use was associated with several confounding clinical and demographic variables including lower education, higher unemployment, not being married or widowed, and history of abuse. After adjusting for these confounding variables, tobacco users continued to have greater pain intensity, a higher total and component FIQ scores except for fatigue. Smoking was not associated with a higher number of tender points. Discussion Current tobacco use was associated with more severe fibromyalgia symptoms in patients presenting to a specialized fibromyalgia treatment program.

Effects of smoking status on immediate treatment outcomes of multidisciplinary pain rehabilitation

OBJECTIVE The primary aim of this study was to determine the effects of smoking on treatment outcomes following multidisciplinary pain rehabilitation. A secondary aim was to assess the tobacco use characteristics of smokers with chronic pain. DESIGN A prospective, nonrandomized, repeated measures design. SETTING Multidisciplinary pain rehabilitation center at a tertiary referral medical center. PATIENTS All patients (N = 193) consecutively admitted from August 2005 through February 2006. INTERVENTIONS A 3-week outpatient multidisciplinary pain rehabilitation program. OUTCOME MEASURES The Multidimensional Pain Inventory (MPI), Short Form-36 Health Status Questionnaire (SF-36), Center for Epidemiologic Studies-Depression scale (CES-D), Pain Anxiety Symptom Scale (PASS-20) and Pain Catastrophizing Scale (PCS) were administered at admission and dismissal. RESULTS The study involved 49 (83% women) smokers and 144 (83% women) nonsmokers. The mean number of cigarettes smoked daily was 17.5 (SD 11.1) and the mean duration of smoking was 21.5 years (SD 12.1). After adjusting for demographic differences, repeated measures of analysis of covariance showed a main effect of smoking status for MPI affective distress (P = 0.008), CES-D (P = 0.001) and PCS (P = 0.011). An interaction of smoking status and time was found for the PASS-20 (P = 0.028), MPI affective distress (P = 0.033), MPI life control (P = 0.003) and SF-36 role-emotional (P = 0.004) subscale. While the majority of smokers were ready to consider smoking abstinence, 43% declined a brief smoking cessation intervention. CONCLUSIONS In this series of patients undergoing multidisciplinary treatment for chronic pain, immediate treatment effects for a variety of outcome measures were similar or significantly better in smokers compared with nonsmokers.