Cancer survivorship and its association with perioperative opioid use for minor non-cancer surgery.

PURPOSE: Reducing high-risk prescription opioid use after surgery has become a key strategy in mitigating the opioid crisis. Yet, despite their vulnerabilities, we know little about how cancer survivors use opioids for non-cancer perioperative pain compared to those with no history of cancer. The purpose was to examine the association of cancer survivorship with the likelihood of receiving perioperative opioid therapy for non-cancer minor surgery. METHODS: Using 2007-2014 SEER-Medicare data for breast, colorectal, prostate, and non-cancer populations, we conducted retrospective cohort study of opioid-naïve Medicare beneficiaries who underwent one of six common minor non-cancer surgeries. Modified Poisson regression estimated the relative risk of receiving a perioperative opioid prescription associated with cancer survivorship compared to no history of cancer. Stabilized inverse probability of treatment weights were used to balance measurable covariates between cohorts. RESULTS: We included 1486 opioid-naïve older adult cancer survivors and 3682 opioid-naïve non-cancer controls. Cancer survivorship was associated with a 5% lower risk of receiving a perioperative opioid prescription (95% confidence interval: 0.89, 1.00; p = 0.06) compared to no history of cancer. Cancer survivorship was not associated with the extent of perioperative opioid exposure. CONCLUSION: Cancer survivors were slightly less likely to receive opioid therapy for non-cancer perioperative pain than those without a history of cancer. It is unclear if this reflects a reduced risk of opioid-related harms for cancer survivors or avoidance of appropriate perioperative pain therapy. Further examination of cancer survivors' experiences with and attitudes about opioids may inform improvements to non-cancer pain management for cancer survivors.

AAAPT Diagnostic Criteria for Acute Low Back Pain with and Without Lower Extremity Pain.

OBJECTIVE: Low back pain is one of the most common reasons for which people visit their doctor. Between 12% and 15% of the US population seek care for spine pain each year, with associated costs exceeding $200 billion. Up to 80% of adults will experience acute low back pain at some point in their lives. This staggering prevalence supports the need for increased research to support tailored clinical care of low back pain. This work proposes a multidimensional conceptual taxonomy. METHODS: A multidisciplinary task force of the ACTTION-APS-AAPM Pain Taxonomy (AAAPT) with clinical and research expertise performed a focused review and analysis, applying the AAAPT five-dimensional framework to acute low back pain. RESULTS: Application of the AAAPT framework yielded the following: 1) Core Criteria: location, timing, and severity of acute low back pain were defined; 2) Common Features: character and expected trajectories were established in relevant subgroups, and common pain assessment tools were identified; 3) Modulating Factors: biological, psychological, and social factors that modulate interindividual variability were delineated; 4) Impact/Functional Consequences: domains of impact were outlined and defined; 5) Neurobiological Mechanisms: putative mechanisms were specified including nerve injury, inflammation, peripheral and central sensitization, and affective and social processing of acute low back pain. CONCLUSIONS: The goal of applying the AAAPT taxonomy to acute low back pain is to improve its assessment through a defined evidence and consensus-driven structure. The criteria proposed will enable more rigorous meta-analyses and promote more generalizable studies of interindividual variation in acute low back pain and its potential underlying mechanisms.

Increased Central Nervous System Interleukin-8 in a Majority Postlaminectomy Syndrome Chronic Pain Population.

Background and Objectives: Multiple processes have been identified as potential contributors to chronic pain, with increasing evidence illustrating an association with aberrant levels of neuroimmune mediators. The primary objectives of the present study were to examine central nervous system cytokines, chemokines, and growth factors present in a chronic pain population and to explore patterns of the same mediator molecules over time. Secondary objectives explored the relationship of central and peripheral neuroimmune mediators while examining the levels of anxiety, depression, sleep quality, and perception of pain associated with the chronic pain patient experience. Methods: Cerebrospinal fluid (CSF) from a population of majority postlaminectomy syndrome patients (N = 8) was compared with control CSF samples (N = 30) to assess for significant differences in 10 cytokines, chemokines, and growth factors. The patient population was then followed over time, analyzing CSF, plasma, and psychobehavioral measures. Results: The present observational study is the first to demonstrate increased mean CSF levels of interleukin-8 (IL-8; P < 0.001) in a small population of majority postlaminectomy syndrome patients, as compared with a control population. Over time in pain patients, CSF levels of IL-8 increased significantly (P < 0.001). Conclusions: These data indicate that IL-8 should be further investigated and psychobehavioral components considered in the overall chronic pain paradigm. Future studies examining the interactions between these factors and IL-8 may identify novel targets for treatment of persistent pain states.

Retrospective Analysis of Intrathecal Drug Delivery: Outcomes, Efficacy, and Risk for Cancer-Related Pain at a High Volume Academic Medical Center.

OBJECTIVES: Cancer pain is common and difficult to treat, as conservative medical management fails in approximately 20% of patients for reasons such as intolerable side-effects or failure to control pain. Intrathecal drug delivery systems (IDDS), while underutilized, can be effective tools to treat intractable cancer pain. This study aims to determine the degree of pain relief, efficacy, and safety of patients who underwent IDDS implantation at a multidisciplinary pain clinic. MATERIALS AND METHODS: A retrospective review was conducted of patients with an intrathecal pain pump implanted for malignant pain. Charts were reviewed for demographics, cancer type, pain scores before and after implantation, and intrathecal drugs utilized. A Wilcoxon Signed-Rank test was conducted on the paired differences of pain scores before and after implant. A regression analysis was conducted using a linear model to assess effects of demographic variables on change in pain scores. RESULTS: 160 patients were included in analysis. The median pain score was 7.1 at time of implantation and 5.0 at one-month postimplantation. For patients with both baseline and one-month pain scores available, the median decrease in pain was 2.5 (p < 0.0001). Pain scores three-month postimplantation did not significantly differ from one-month postimplantation. Median longevity was 65 days. Five patients had pumps explanted due to infection with a median time to pump extraction of 28 days. CONCLUSIONS: IDDS has the potential to improve cancer pain in a variety of patients and should be strongly considered as an option for those with cancer pain intractable to conservative medical management.

Alternatives to Opioids in the Pharmacologic Management of Chronic Pain Syndromes: A Narrative Review of Randomized, Controlled, and Blinded Clinical Trials.

Chronic pain exerts a tremendous burden on individuals and societies. If one views chronic pain as a single disease entity, then it is the most common and costly medical condition. At present, medical professionals who treat patients in chronic pain are recommended to provide comprehensive and multidisciplinary treatments, which may include pharmacotherapy. Many providers use nonopioid medications to treat chronic pain; however, for some patients, opioid analgesics are the exclusive treatment of chronic pain. However, there is currently an epidemic of opioid use in the United States, and recent guidelines from the Centers for Disease Control (CDC) have recommended that the use of opioids for nonmalignant chronic pain be used only in certain circumstances. The goal of this review was to report the current body of evidence-based medicine gained from prospective, randomized-controlled, blinded studies on the use of nonopioid analgesics for the most common noncancer chronic pain conditions. A total of 9566 studies were obtained during literature searches, and 271 of these met inclusion for this review. Overall, while many nonopioid analgesics have been found to be effective in reducing pain for many chronic pain conditions, it is evident that the number of high-quality studies is lacking, and the effect sizes noted in many studies are not considered to be clinically significant despite statistical significance. More research is needed to determine effective and mechanism-based treatments for the chronic pain syndromes discussed in this review. Utilization of rigorous and homogeneous research methodology would likely allow for better consistency and reproducibility, which is of utmost importance in guiding evidence-based care.

Neurophysiological and Clinical Effects of Laparoscopic Retroperitoneal Triple Neurectomy in Patients with Refractory Postherniorrhaphy Neuropathic Inguinodynia.

BACKGROUND: Chronic postherniorrhaphy inguinal pain (CPIP) is a complex, major health problem. In the absence of recurrence or meshoma, laparoscopic retroperitoneal triple neurectomy (LRTN) has emerged as an effective surgical treatment of CPIP. METHODS: This prospective pilot study evaluated the neurophysiological and clinical effects of LRTN. Ten consecutive adult CPIP patients with unilateral predominantly neuropathic inguinodynia underwent three comprehensive quantitative sensory testing (QST) assessments (preoperative, immediate postoperative, and late postoperative). Pain severity, health-related function, and sleep quality were assessed over the course of a 6-month follow-up period. RESULTS: QST revealed marked increases in mechanical, pressure, thermal, and pain thresholds in the areas with maximum pain prior to LRTN surgery for the immediate (P < 0.01; mean 160.9 minutes, range 103 to 255 minutes after extubation) and late postoperative (P < 0.05; mean 27.9 days, range 14 to 78 days after surgery) assessments compared to baseline. Wind-up phenomena were eliminated postoperatively. LRTN provided robust group-level improvements of all clinical measures. No preoperative QST variables were found to be predictive of surgical outcomes. The positive change in heat pain threshold (preoperative compared to late postoperative) showed significant positive correlations with improvements of pain scores and function. CONCLUSIONS: LRTN may produce immediate, profound, and consistent positive effects across multiple mechanical, pressure, and thermal QST variables, and marked improvements of clinical outcomes in selected CPIP patients. These data contribute to the understanding of mechanisms involved in the success of LRTN. Large, high-powered studies are warranted to determine whether preoperative or repeated longitudinal QST may guide patient selection and predict effectiveness of LRTN.

Botulinum toxin type a injections for cervical and shoulder girdle myofascial pain using an enriched protocol design.

BACKGROUND: Myofascial pain syndrome is a regional condition of muscle pain and stiffness and is classically characterized by the presence of trigger points in affected musculature. Botulinum toxin type A (BoNT-A) has been shown to have antinociceptive properties and elicit sustained muscle relaxation, thereby possibly affording even greater relief than traditional strategies. Our goal was to determine whether direct injection of BoNT-A into painful muscle groups is effective for cervical and shoulder girdle myofascial pain. METHODS: An enriched protocol design was used, wherein 114 patients with cervical and shoulder girdle myofascial pain underwent injection of BoNT-A to determine their response to the drug. Fifty-four responders were then enrolled in a 12-week, randomized, double-blind, placebo-controlled trial. Pain scales and quality of life measures were assessed at baseline and at routine follow-up visits until completion of the study after 26 weeks. RESULTS: Injection of BoNT-A into painful muscle groups improved average visual numerical pain scores in subjects who received a second dose of BoNT-A compared to placebo (P = 0.019 [0.26, 2.78]). Subjects who received a second dose of BoNT-A had a reduced number of headaches per week (P = 0.04 [0.07, 4.55]). Brief Pain Inventory interference scores for general activity and sleep were improved (P = 0.046 [0.038, 3.700] and 0.02 [0.37, 4.33], respectively) in those who received a second dose of BoNT-A. CONCLUSION: BoNT-A injected directly into painful muscle groups improves average pain scores and certain aspects of quality of life in patients experiencing severe cervical and shoulder girdle myofascial pain.

A Subgroup of Chronic Low Back Pain Patients With Central Sensitization.

BACKGROUND: Our knowledge of central sensitization (CS) in chronic low back pain (CLBP) is limited. 2011 fibromyalgia criteria and severity scales (2011 FM survey) have been used to determine FM positive as a surrogate of CS. The major features of CS including widespread hyperalgesia and dysfunction of the descending inhibitory pathways can be identified by pressure pain threshold (PPT) and conditioned pain modulation (CPM) tests. The purpose of the study was to examine neurophysiological characteristics and psychosocial symptoms in a subgroup of FM-positive CLBP compared with FM-negative CLBP patients. METHODS: A total of 46 participants with CLBP and 22 pain-free controls completed outcome measures of the 2011 FM survey, PPT and CPM tests, and psychosocial questionnaires. Differences between FM-positive and FM-negative CLBP participants on these measures and correlations were analyzed. RESULTS: The 2011 FM survey identified 22 (48%) participants with CLBP as FM positive. FM-positive CLBP participants showed lower PPT values of the thumbnail (P=0.011) and lower back (P=0.003), lower CPM values of the thumbnail (P=0.002), and more severe pain catastrophizing, anxiety, and depression symptoms (P<0.05) than FM-negative CLBP participants. The 2011 FM scores were significantly correlated with the PPT and CPM values of the thumbnail and with psychosocial symptoms (P<0.001). DISCUSSION: Our findings suggest a subgroup of CLBP patients exhibiting with signs and symptoms of CS. Associations between subjective and objective CS measures indicate that the 2011 FM survey can be utilized to identify the presence of CS in CLBP in clinical practice.

Potential Mechanisms Underlying Centralized Pain and Emerging Therapeutic Interventions.

Centralized pain syndromes are associated with changes within the central nervous system that amplify peripheral input and/or generate the perception of pain in the absence of a noxious stimulus. Examples of idiopathic functional disorders that are often categorized as centralized pain syndromes include fibromyalgia, chronic pelvic pain syndromes, migraine, and temporomandibular disorder. Patients often suffer from widespread pain, associated with more than one specific syndrome, and report fatigue, mood and sleep disturbances, and poor quality of life. The high degree of symptom comorbidity and a lack of definitive underlying etiology make these syndromes notoriously difficult to treat. The main purpose of this review article is to discuss potential mechanisms of centrally-driven pain amplification and how they may contribute to increased comorbidity, poorer pain outcomes, and decreased quality of life in patients diagnosed with centralized pain syndromes, as well as discuss emerging non-pharmacological therapies that improve symptomology associated with these syndromes. Abnormal regulation and output of the hypothalamic-pituitary-adrenal (HPA) axis is commonly associated with centralized pain disorders. The HPA axis is the primary stress response system and its activation results in downstream production of cortisol and a dampening of the immune response. Patients with centralized pain syndromes often present with hyper- or hypocortisolism and evidence of altered downstream signaling from the HPA axis including increased Mast cell (MC) infiltration and activation, which can lead to sensitization of nearby nociceptive afferents. Increased peripheral input via nociceptor activation can lead to "hyperalgesic priming" and/or "wind-up" and eventually to central sensitization through long term potentiation in the central nervous system. Other evidence of central modifications has been observed through brain imaging studies of functional connectivity and magnetic resonance spectroscopy and are shown to contribute to the widespreadness of pain and poor mood in patients with fibromyalgia and chronic urological pain. Non-pharmacological therapeutics, including exercise and cognitive behavioral therapy (CBT), have shown great promise in treating symptoms of centralized pain.

Reducing Radiation Exposure in Lumbar Transforaminal Epidural Steroid Injections with Pulsed Fluoroscopy: A Randomized, Double-blind, Controlled Clinical Trial.

BACKGROUND: Fluoroscopy-guided lumbar transforaminal epidural steroid injections (L-TFESI) result in radiation exposure that carries risks to patients, physicians, and procedural staff. OBJECTIVE: We aim to evaluate the feasibility of using pulsed fluoroscopy to safely reduce radiation exposure during L-TFESI. STUDY DESIGN: This is a prospective, double-blind, randomized controlled trial. SETTING: This study took place in a single-center, academic, outpatient interventional pain management clinic. METHODS: Patients undergoing L-TFESI were randomly assigned to either continuous mode fluoroscopy (high-dose), pulsed fluoroscopy with 8 pulses per second (medium-dose), or pulsed fluoroscopy with one pulse per second (low-dose). Data on radiation doses and other clinical and demographic factors were also collected. RESULTS: In total, 231 cases were analyzed in the high-dose group (n = 81), medium-dose group (n = 72), and low-dose group (n = 78). Mean radiation effective dose (µSv) was 121 in the high-dose group, 57.9 in the medium-dose group, and 34.8 in the low-dose group (P < 0.001). The incidence of inadequate image quality in the pulsed groups was 6% (9/150). The body mass index (BMI, mean ± SD) was significantly higher in patients with inadequate image quality (37.3 ± 7.2) than with adequate quality (30.5 ± 7.2, P = 0.005). LIMITATIONS: Radiation doses were measured using the meter on C-arm fluoroscopes rather than by direct measurement. CONCLUSIONS: The use of pulsed fluoroscopy during L-TFESI resulted in radiation dose reduction of up to 72.1% without causing any significant adverse events. Pulsed fluoroscopy should be considered as an initial fluoroscopic setting for L-TFESI to reduce radiation exposure. KEY WORDS: Radiation, epidural, fluoroscopy, injection, exposure, pulse.

The Association Between a History of Lifetime Traumatic Events and Pain Severity, Physical Function, and Affective Distress in Patients With Chronic Pain.

Evidence suggests that pain patients who report lifetime abuse experience greater psychological distress, have more severe pain and other physical symptoms, and greater functional disability. The aim of the present study was to determine the associations between a history of lifetime abuse and affective distress, fibromyalgianess (measured using the 2011 Fibromyalgia Survey), pain severity and interference, and physical functioning. A cross-sectional analysis of 3,081 individuals presenting with chronic pain was performed using validated measures and a history of abuse was assessed via patient self-report. Multivariate logistic regression showed that individuals with a history of abuse (n = 470; 15.25%) had greater depression, greater anxiety, worse physical functioning, greater pain severity, worse pain interference, higher catastrophizing, and higher scores on the Fibromyalgia Survey criteria (P < .001 for all comparisons). Mediation models showed that the Fibromyalgia Survey score and affective distress independently mediate the relationship between abuse and pain severity and physical functioning (Ps < .001). Our mediation models support a novel biopsychosocial paradigm wherein affective distress and fibromyalgianess interact to play significant roles in the association between abuse and pain. We posit that having a centralized pain phenotype underlies the mediation of increased pain morbidity in individuals with a history of abuse. PERSPECTIVE: This article examines the associations between a history of lifetime abuse and affective distress, fibromyalgianess, pain severity and interference, and physical functioning in chronic pain patients. Our findings support a novel biopsychosocial paradigm in which affective distress and fibromyalgianess interact to play roles in the association between abuse and pain.

Efficacy of needle-placement technique in radiofrequency ablation for treatment of lumbar facet arthropathy.

BACKGROUND: Many studies have assessed the efficacy of radiofrequency ablation to denervate the facet joint as an interventional means of treating axial low-back pain. In these studies, varying procedural techniques were utilized to ablate the nerves that innervate the facet joints. To date, no comparison studies have been performed to suggest superiority of one technique or even compare the prevalence of side effects and complications. MATERIALS AND METHODS: A retrospective chart review was performed on patients who underwent a lumbar facet denervation procedure. Each patient's chart was analyzed for treatment technique (early versus advanced Australian), preprocedural visual numeric scale (VNS) score, postprocedural VNS score, duration of pain relief, and complications. RESULTS: Pre- and postprocedural VNS scores and change in VNS score between the two groups showed no significant differences. Patient-reported benefit and duration of relief was greater in the advanced Australian technique group (P=0.012 and 0.022, respectively). The advanced Australian technique group demonstrated a significantly greater median duration of relief (4 months versus 1.5 months, P=0.022). Male sex and no pain-medication use at baseline were associated with decreased postablation VNS scores, while increasing age and higher preablation VNS scores were associated with increased postablation VNS scores. Despite increasing age being associated with increased postablation VNS scores, age and the advanced Australian technique were found to confer greater patient self-reported treatment benefit. CONCLUSION: The advanced Australian technique provides a significant benefit over the early Australian technique for the treatment of lumbar facet pain, both in magnitude and duration of pain relief.

Pain control following inguinal herniorrhaphy: current perspectives.

Inguinal hernia repair is one of the most common surgeries performed worldwide. With the success of modern hernia repair techniques, recurrence rates have significantly declined, with a lower incidence than the development of chronic postherniorrhaphy inguinal pain (CPIP). The avoidance of CPIP is arguably the most important clinical outcome and has the greatest impact on patient satisfaction, health care utilization, societal cost, and quality of life. The etiology of CPIP is multifactorial, with overlapping neuropathic and nociceptive components contributing to this complex syndrome. Treatment is often challenging, and no definitive treatment algorithm exists. Multidisciplinary management of this complex problem improves outcomes, as treatment must be individualized. Current medical, pharmacologic, interventional, and surgical management strategies are reviewed.