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Objectives Pulsed radiofrequency (PRF) stimulation is widely used for intractable pain; however, there is no consensus on treatment protocols and appropriate types of pain. We compared effectiveness of bipolar and unipolar PRF on neuropathic or inflammatory pains, and of targets at the dorsal root ganglion (DRG) and sciatic nerve (SN). We also examined efficacy of repetitive PRF stimulations. This preclinical study could serve as an extensive survey before human trials. Materials Spare nerve injury (SNI)-induced neuropathic pain and complete Freund's adjuvant (CFA) injection-induced inflammatory pain were used. Behavioral responses were measured using von Frey test, acetone test, and Hargreave's test at preinjury and postinjury time points. In both models, we evaluated results of DRG stimulation with unipolar PRF (45 V) versus bipolar PRF (5 V), stimulation at DRG vs. SN, and repetitive stimulations. Results Both unipolar and bipolar PRFs reduced SNI- or CFA-induced pain for a similar duration. In the SNI model, PRF-DRG had a stronger effect on tactile pain than PRF-SN but lower effect on cold allodynia, whereas in the CFA model PRF-DRG and PRF-SN showed similar effects. Repetitive PRF stimulation, by open technique or implantation method, produced analogous effect by each stimulus, and no evident analgesic tolerance or neurological deficit was shown. Conclusions PRF temporarily attenuates neuropathic and inflammatory pain. Bipolar PRF generates significant analgesia with a much lower electrical power than unipolar PRF. Meanwhile, the minor variant effects between PRF-DRG and PRF-SN may indicate distinct mechanisms. The sustained-analgesia by repetitive treatments suggests implantation technique could be a promising choice.

Cyclo-oxygenase (COX)-2 selective and nonselective nonsteroidal anti-inflammatory drugs (NSAIDs) are important in managing acute and chronic pain secondary to inflammation. As a greater understanding of the risks of gastrointestinal (GI), cardiovascular (CV) and renal events with NSAIDs use has emerged, guidelines have evolved to reflect differences in risks among NSAIDs. Updated guidelines have yet to reflect new evidence from recent trials which showed similar CV event rates with celecoxib compared to naproxen and ibuprofen, and significantly better GI tolerability for celecoxib. This practice advisory paper aims to present consensus statements and associated guidance regarding appropriate NSAID use based on a review of current evidence by a multidisciplinary group of expert clinicians. This paper is especially intended to guide primary care practitioners within Asia in the appropriate use of NSAIDs in primary care. Following a literature review, group members used a modified Delphi consensus process to determine agreement with selected recommendations. Agreement with a statement by 75% of total voting members was defined a priori as consensus. For low GI risk patients, any nonselective NSAID plus proton pump inhibitor (PPI) or celecoxib alone is acceptable treatment when CV risk is low; for high CV risk patients, low-dose celecoxib or naproxen plus PPI is appropriate. For high GI risk patients, celecoxib plus PPI is acceptable for low CV risk patients; low-dose celecoxib plus PPI is appropriate for high CV risk patients, with the alternative to avoid NSAIDs and consider opioids instead. Appropriate NSAID prescription assumes that the patient has normal renal function at commencement, with ongoing monitoring recommended. In conclusion, appropriate NSAID use requires consideration of all risks.

Despite having been referenced in the literature for over a decade, the term “mixed pain” has never been formally defined. The strict binary classification of pain as being either purely neuropathic or nociceptive once left a good proportion of patients unclassified; even the recent adoption of “nociplastic pain” in the IASP Terminology leaves out patients who present clinically with a substantial overlap of nociceptive and neuropathic symptoms. For these patients, the term “mixed pain” is increasingly recognized and accepted by clinicians. Thus, an independent group of international multidisciplinary clinicians convened a series of informal discussions to consolidate knowledge and articulate all that is known (or, more accurately, thought to be known) and all that is not known about mixed pain. To inform the group’s discussions, a Medline search for the Medical Subject Heading “mixed pain” was performed via PubMed. The search strategy encompassed clinical trial articles and reviews from January 1990 to the present. Clinically relevant articles were selected and reviewed. This paper summarizes the group’s consensus on several key aspects of the mixed pain concept, to serve as a foundation for future attempts at generating a mechanistic and/or clinical definition of mixed pain. A definition would have important implications for the development of recommendations or guidelines for diagnosis and treatment of mixed pain. © 2019, © 2019 Informa UK Limited, trading as Taylor and Francis Group.

Introduction Optimal pain management is crucial to the postoperative recovery process. We aimed to evaluate the efficacy and safety of intravenous oxycodone with intravenous fentanyl, morphine, sufentanil, pethidine, and hydromorphone for acute postoperative pain. Methods A systematic literature search of PubMed, Cochrane Library, and EMBASE databases was performed for randomized controlled trials published from 2008 through 2017 (inclusive) that evaluated the acute postoperative analgesic efficacy of intravenous oxycodone against fentanyl, morphine, sufentanil, pethidine, and hydromorphone in adult patients (age ≥ 18 years). Outcomes examined included analgesic consumption, pain intensity levels, side effects, and patient satisfaction. Results Eleven studies were included in the review; six compared oxycodone with fentanyl, two compared oxycodone with morphine, and three compared oxycodone with sufentanil. There were no eligible studies comparing oxycodone with pethidine or hydromorphone. Overall, analgesic consumption was lower with oxycodone than with fentanyl or sufentanil. Oxycodone exhibited better analgesic efficacy than fentanyl and sufentanil, and comparable analgesic efficacy to morphine. In terms of safety, there was a tendency towards more side effects with oxycodone than with fentanyl, but the incidence of side effects with oxycodone was comparable to morphine and sufentanil. Where patient satisfaction was evaluated, higher satisfaction levels were observed with oxycodone than with sufentanil and comparable satisfaction was noted when comparing oxycodone with fentanyl. Patient satisfaction was not evaluated in the studies comparing oxycodone with morphine. Conclusions Our findings suggest that intravenous oxycodone provides better analgesic efficacy than fentanyl and sufentanil, and comparable efficacy to morphine with less adverse events such as sedation. No studies comparing intravenous oxycodone with pethidine or hydromorphone were identified in this review. Better alignment of study methodologies for future research in this area is recommended to provide the best evidence base for a meta-analysis. Funding Mundipharma Singapore Holding Pte Ltd, Singapore. Electronic supplementary material The online version of this article (10.1007/s40122-019-0122-4) contains supplementary material, which is available to authorized users.

COX2-selective and nonselective (ns) nonsteroidal anti-inflammatory drugs (NSAIDs) are widely used for chronic pain management. There are marked differences in the risk of adverse gastrointestinal (GI) and cardiovascular (CV) events among different NSAIDs. In 2017, publication of two randomized controlled trials and an individual patient-data meta-analysis provided robust data on the relative GI and CV tolerability profiles of currently available NSAIDs. The PRECISION study showed similar CV-event rates with celecoxib vs naproxen and ibuprofen, but GI tolerability was better for celecoxib. In the CONCERN study of high-GI-risk patients, celecoxib was associated with fewer adverse GI-tract events than naproxen. The meta-analysis showed no significant difference between celecoxib and ns-NSAIDs in the rate of acute myocardial infarction, and celecoxib was the only COX2-selective NSAID with a lower risk of adverse CV and GI events vs ns-NSAIDs. These data add to the body of knowledge about the relative tolerability of different NSAIDs and were used to propose an updated treatment algorithm. The decision about whether to use an NSAID and which one should be based on a patient’s risk of developing adverse GI and CV events. Lower- and upper-GI-tract events need to be considered. Celecoxib has a better lower-GI-tract tolerability profile than ns-NSAIDs plus a proton-pump inhibitor. In addition, the latest data suggest that long-term use of celecoxib 200 mg/day may be appropriate for patients at increased CV risk. Published version

In order to implement more effective policies for cancer pain management, a better understanding of current practices is needed. Physicians managing cancer pain and patients experiencing cancer pain were randomly surveyed across 10 Asian countries to assess attitudes and perceptions toward cancer pain management. A total of 463 physicians (77.3% oncologists) with a median experience of 13 years were included. Medical school training on opioid use was considered inadequate by 30.5% of physicians and 55.9% indicated ≤ 10 h of continuing medical education (CME). Of the 1190 patients included, 1026 reported moderate-to-severe pain (median duration, 12 months). Discordance was observed between physician and patient outcomes on pain assessment with 88.3% of physicians reporting pain quantification, while 49.5% of patients claimed that no scale was used. Inadequate assessment of pain was recognized as a barrier to therapy optimization by 49.7% of physicians. Additional barriers identified were patients' reluctance owing to fear of addiction (67.2%) and adverse events (65.0%), patients' reluctance to report pain (52.5%), excessive regulations (48.0%) and reluctance to prescribe opioids (42.8%). Opioid use was confirmed only in 53.2% (286/538) of patients remembering their medication. Pain affected the activities of daily living for 81.3% of patients. These findings highlight the need for better training and CME opportunities for cancer pain management in Asia. Collaborative efforts between physicians, patients, policy makers, and related parties may assist in overcoming the barriers identified. Addressing the opioid stigma and enhancing awareness is vital to improving current standards of patient care.

Introduction: While opioids are effective in carefully selected patients with chronic non-cancer pain (CNCP), they are associated with potential risks. Therefore, treatment recommendations for the safe and effective use of opioids in this patient population are needed. Materials and Methods: A multidisciplinary expert panel was convened by the Pain Association of Singapore to develop practical evidence-based recommendations on the use of opioids in the management of CNCP in the local population. This article discusses specific recommendations for various common CNCP conditions. Results: Available data demonstrate weak evidence for the long-term use of opioids. There is moderate evidence for the short-term benefit of opioids in certain CNCP conditions. Patients should be carefully screened and assessed prior to starting opioids. An opioid treatment agreement must be established, and urine drug testing may form part of this agreement. A trial duration of up to 2 months is necessary to determine efficacy, not only in terms of pain relief, but also to document improvement in function and quality of life. Regular reviews are essential with appropriate dose adjustments, if necessary, and routine assessment of analgesic efficacy, aberrant behaviour and adverse effects. The reasons for discontinuation of opioid therapy include side effects, lack of efficacy and aberrant drug behaviour. Conclusion: Due to insufficient evidence, the task force does not recommend the use of opioids as first-line treatment for various CNCP. They can be used as second- or third-line treatment, preferably as part of a multimodal approach. Additional studies conducted over extended periods are required. Key words: Chronic pain, Consensus statement, Guidelines, Non-cancer pain, Opioids

Aim To examine the treatment practices for cancer pain relief and adverse event management, and the factors related to patient outcomes in the participating countries/regions. Methods The study was a cross-sectional survey conducted between September and December 2013 in 10 countries/regions across Asia. Adult patients with a history of cancer pain at least 1 month before study entry completed the survey questionnaire. Results A total of 1190 patients were included. The mean Box Scale-11 (BS-11) pain score was 6.0 (SD 2.1), with 86.2% experiencing moderate-to-severe pain and 53.2% receiving opioids at time of the survey. The mean BS-11 scores were 5.3 (SD 2.1) in the “others” (single non-opioid medication or untreated) group, 6.3 (SD 2.0) in the ≥2 non-opioids group and 6.7 (SD 1.9) in the opioid group. The proportions of patients experiencing moderate-to-severe pain were 79.1%, 87.3% and 93.7%, respectively. About 70% of patients reported adverse events due to their pain medications, about half had received medications to manage these symptoms. Adverse events were negatively associated with activities of daily living (P < 0.0001). Pain and hindrance to activities of daily living were negatively associated with employment status (P = 0.003 and 0.021). Unemployment was significantly associated with poorer quality of life (P < 0.0001). Conclusion This analysis demonstrates inadequate management of cancer pain and treatment-related adverse events in the participating cohort. Pain and inadequate management of adverse events were negatively associated with patients’ overall well-being. More collaborative efforts should be taken to optimize pain treatment and increase awareness of adverse event management in physicians.

Study Objective To evaluate the effect of chronic hepatic disease on postoperative coagulation. Design Retrospective cohort study. Setting Operating room with postoperative inpatient followup. Measurements The records of 153 patients who underwent elective open hepatic resection were reviewed. The perioperative coagulation profile of each patient was assessed. The postoperative period was subdivided into the early [postoperative day (POD) 0–3] and late (POD 4 - POD 7) periods. Main Results 68 (44.4%) patients had chronic hepatic disease and 50 (32.7%) had cirrhosis. Eighty-four (54.9%) patients had an abnormal early postoperative coagulation profile and 46 (30.1%) had an abnormal late postoperative coagulation profile. The proportion of patients having an abnormal coagulation profile peaked on POD 2, at 39.2%. Only 5.3% of patients had an abnormal coagulation profile on POD 7. The independent predictors of abnormal early and late postoperative coagulation profiles were preexisting hepatic cirrhosis [early: odds ratio (OR) 3.73(1.49 - 9.29), late: OR 6.84(2.11 - 22.21)], abnormal preoperative coagulation profile [early: OR 9.68 (1.97 - 47.5), late: OR 11.71 (3.61- 38.02)], major hepatic resection [early: OR 4.15 (1.66 - 10.4), late: OR 5.43 (1.68 - 17.47)], and intraoperative blood loss. Conclusions An abnormal postoperative coagulation profile after hepatic surgery is common in a patient population with chronic hepatic disease.

Introduction: Cancer pain is one of the most frequently encountered pain syndromes. With the application of the World Health Organization analgesic ladder, adequate analgesia is achieved in 75% to 90% of patients. The remaining patients suffer from intractable pain requiring intra- thecal analgesia. The aim of this study was to retrospectively analyse the pain intensity before and after intrathecal analgesia and review the complications associated with the implantation and the care of the intrathecal device. Materials and Methods: We reviewed medical records of all cancer patients whose pain were managed by intrathecal catheter implants in our centre from February 2005 to August 2008. The pain intensity, medication and complications related to intrathecal catheter insertion or drug delivery were reviewed at the time before starting the intrathecal analgesia (T0) and time of discharge from the hospital/time prior to death during their stay in the hospital (Tdsc). Results: Twenty-nine patients were included. Out of these 29 patients, 86.2% had metastatic cancer. The most common indication was poor pain control. Pain intensity was reduced significantly at the time of discharge from hospital (P

Summary Background Postoperative analgesic modalities include patient-controlled techniques via various routes such as intravenous and epidural. A transdermal delivery route using iontophoretic technology appears promising. Recent randomised controlled trials have suggested that fentanyl iontophoretic transdermal system (ITS) was of equivalent efficacy to intravenous morphine patient-controlled analgesia (PCA). The objective of this meta-analysis was to assess the efficacy and safety of this system in the management of acute postoperative pain. Methods A meta-analysis of two placebo-controlled and four active-controlled randomised trials which satisfied the inclusion criteria was performed according to the QUOROM guidelines. Results Fentanyl ITS was superior to placebo for postoperative analgesia using withdrawal secondary to inadequate analgesia and pain scores as outcome measures. Fentanyl ITS was equivalent to morphine PCA when Patient Global Assessment was used as primary outcome measure. However, there were significantly more patients in the fentanyl ITS group who withdrew due to inadequate analgesia. This may be related to the pharmacokinetic profile of fentanyl ITS. Adverse effect and safety profile seemed favourable. Conclusions Fentanyl ITS is a promising novel modality for postoperative analgesia that is superior to placebo but may not be equivalent to morphine PCA as claimed by individual trials and recent reviews. Its use appears to be safe.

Background: Chronic pain is a debilitating problem with significant impact on healthcare utilization in the US. Many chronic pain patients use complementary or alternative medicine (CAM) in addition to standard pharmacologic therapy. Objective: The aim of our study was to identify differences in the characteristics of usage of CAM for chronic pain control among several ethnic groups. Design: We recruited 92 consecutive patients seeking treatment at the pain clinic and interviewed them using a questionnaire. Results: The most common pain complaint was back pain (55.4%) and the mean pain duration for all chronic pain problems was 9.8 years. Approximately 81% of respondents were using or have used CAM before. The commonest CAM used by patients in our study included massage therapy, spiritual healing as well as the consumption of mineral and vitamin supplements. Sixty-three percent of them were satisfied with CAM treatment compared to 56% of patients who were satisfied with prescription therapy. However, there was no difference in the use of CAM among the different ethnic groups (P > 0.05). Conclusion: Our study demonstrates that CAM is used very frequently in patients with chronic pain. However, it did not show any ethnic or racial differences in CAM utilization. Key words: Complementary and alternative medicine, ethnicity, racial differences, chronic pain

Chronic non-cancer pain is a common clinical condition affecting a significant part of the population. This article aims to review the interventional options for non-cancer pain. Multiple searches using Medline were carried out and additional searches were made using reference lists of published papers and book chapters. The article discussed procedures ranging from selective nerve root or zygapophyseal (facet) joint block with local anaesthetics to irreversible neurodestruction with radiofrequency energy or neurolytic agents and neuromodulation with spinal cord stimulation. Other techniques include intraspinal delivery of analgesics. There is evidence that these interventional procedures are valuable both diagnostically and therapeutically. Key words: Intrathecal drug delivery, Neuropathic, Spine

Objective: Oral amitriptyline, a tricyclic antidepressant, is effective for treating neuropathic pain. We conducted a double-blind, randomized, placebo-controlled crossover study to evaluate the efficacy of topical 5% amitriptyline and 5% lidocaine in treating patients with neuropathic pain. Methods: Thirty-five patients with postsurgical neuropathic pain, postherpetic neuralgia, or diabetic neuropathy with allodynia or hyperalgesia were assigned to receive 3 topical creams (5% amitriptyline, 5% lidocaine, or placebo) in random sequence. The primary outcome measure was change in pain intensity (baseline vs. posttreatment average pain) using a 0 to 100 mm Visual Analog Scale. Secondary outcome measures included the McGill Pain Questionnaire, requirement for rescue medication, and patient satisfaction. Primary statistical comparisons were made with paired t tests or signed-rank tests. Results: A reduction in pain intensity was observed with topical lidocaine (P < 0.05). No significant change in pain intensity was found with topical amitriptyline or placebo. In pairwise comparison of treatments, topical lidocaine and placebo each reduced pain more than topical amitriptyline (P < 0.05). Discussion: This randomized, placebo-controlled crossover study examining topical 5% amitriptyline and 5% lidocaine in the treatment of neuropathic pain showed that topical lidocaine reduced pain intensity but the clinical improvement is minimal and that topical 5% amitriptyline was not effective.

The piriformis muscle syndrome has been described in the literature since 1947 and accounts for 6-8% of patients presenting with buttock pain, which may variably be associated with sciatica. Through the years, there have been attempts to find safe and effective ways of managing this condition, whether through conservative treatment or with the use of interventional procedures. Several authors have reported injection techniques using the following: nerve stimulation; fluoroscopy with electromyography; and fluoroscopy with muscle stimulation. We aim to describe an injection method which is effective, simple, reproducible, easily available, and safe. This is the first report on the combined use of ultrasonography and motor stimulation in performing piriformis muscle injection. Our technique offers advantages such as: markedly decreased radiation exposure for both patient and doctor; improved visualization of sciatic nerve and surrounding muscles; improved portability; the possibility of being performed as an office-based procedure; and allows for an accurate confirmation of pain in the piriformis muscle with stimulation. Key words: Piriformis muscle, ultrasound, motor stimulation

Botulinum toxin injection is used to treat various pain conditions including muscle spasticity, dystonia, headache and myofascial pain. Results are conflicting regarding the use of Botulinum toxin for trigger point injection in terms of improvement in pain. The aim of this study was to carry out a systematic review to assess the evidence for efficacy of Botulinum toxin A (BTA) compared with placebo for myofascial trigger point injection. Electronic databases on Medline, Cochrane Library, Scopus, CINAHL were queried using key words such as "botulinum toxin", "myofascial pain", "trigger point", "chronic pain" and "musculoskeletal pain". Relevant published randomized controlled trials that described the use of BTA as injection therapy for trigger points were considered for inclusion. The five-item 0-16 point Oxford Pain Validity Scale (OPVS) was used as a selection criteria for suitable clinical trials. Trials were also assessed based on quality using the Oxford Rating Scale. Data extracted from qualified trials included outcome measures such as pain intensity and pain pressure threshold. All studies were ranked according to the OPVS and the authors' conclusions were compared. Five clinical trials met the inclusion criteria. One trial concluded that BTA was effective, and four concluded that it was not effective for reducing pain arising from trigger points. OPVS scores ranged from 8 to 14 with the negative studies corresponding with higher validity scores. The current evidence does not support the use of BTA injection in trigger points for myofascial pain. The data is limited and clinically heterogeneous.

The objective of this systematic review was to evaluate the efficacy and tolerability of perioperative gabapentin administration for the control of acute postoperative pain. We searched Medline (1966–2006), the Cochrane Library (2006), Scopus, CINAHL and bibliographies from clinical trials and review articles. We included randomized controlled trials (RCTs) comparing gabapentin with inactive controls in surgical patients. Sixteen valid RCTs were included. Weighted mean difference (WMD) for postoperative pain intensity (0–100 mm visual analogue scale) was −16.55 mm at 6 h and −10.87 mm at 24 h for treatment with a single preoperative dose of gabapentin 1200 mg. Cumulative opioid consumption at 24 h was also significantly decreased with gabapentin (WMD, −27.90 mg). When gabapentin was administered at doses less than 1200 mg, pain intensity was also lower at 6 h (WMD, −22.43 mm) and 24 h (WMD, −13.18 mm). Cumulative 24 h opioid consumption was also lower (WMD, −7.25 mg). Gabapentin was associated with an increased risk of sedation (Peto OR 3.86; 95% CI 2.50–5.94) but less opioid-related side effects such as vomiting (Peto OR 0.58; 95% CI 0.39–0.86) and pruritus (Peto OR 0.27; 95% CI 0.10–0.74). In conclusion, gabapentin has an analgesic and opioid-sparing effect in acute postoperative pain management when used in conjunction with opioids.

The use of selective 5-hydroxytryptamine type 3 receptor antagonists has improved the management of postoperative nausea and vomiting, but has not completely eliminated it. In this article, we discuss the pharmacology of 5-hydroxytryptamine type 3 receptor antagonists and the impact of pharmacogenetics on postoperative nausea and vomiting.Dolasetron, granisetron, ondansetron, palonosetron, and tropisetron have similar mechanisms of action but different pharmacokinetic and pharmacodynamic properties. Genetic polymorphism in the cytochrome P450 mono-oxygenase system, drug efflux transporter adenosine triphosphate-binding cassette subfamily B member 1 and 5-hydroxytryptamine type 3 receptor subunits also contribute to the interindividual variation in response to different 5-hydroxytryptamine type 3 receptor antagonists. These differences account for differences in the duration of action and clinical efficacy of these agents.Pharmacogenetics testing in patients may help differentiate responders to 5-hydroxytryptamine type 3 receptor antagonists from non-responders and allow the anesthesiologist to individualize antiemetic therapy. The cost-effectiveness of such screening in postoperative nausea and vomiting management has, however, not been evaluated. Given the multifactorial nature of postoperative nausea and vomiting, a multimodal approach to reduce or eliminate risk factors will be most successful in its management.

Summary Background : This study was conducted to determine if a double-breath (DB) vital capacity (VC) rapid inhalation induction using immediate high-inspired concentration of sevoflurane is as well tolerated as a single-breath (SB) technique and if it results in a shorter induction time. Methods : A total of 104 children, ASA I-II, 6 year and above, undergoing elective surgery were randomly assigned to two groups: SB VC inhalation induction or DB VC inhalation induction with 8% sevoflurane in 66% nitrous oxide. The induction time, complications (cough, laryngospasm, breath-hold, movement, salivation) and level of satisfaction were documented. Results : Induction was significantly faster in the DB group (41 ± 9 s) compared with the SB group (50 ± 14 s). DB inhalation induction was associated with fewer complications (15.4%) than the SB technique (50%). Conclusions : Double-breath VC inhalation induction with 8% sevoflurane is as well tolerated as a SB technique and results in a faster onset of anaesthesia.

Cancer pain is prevalent, undertreated, and feared by patients with cancer. In April 2013, a panel of pain experts convened in Singapore to address the treatment of cancer pain. They discussed the various types of cancer pain, including breakthrough pain, which is sometimes clinically confused with analgesic gaps. Reasons for undertreating cancer pain include attitudes of patients, clinicians, and factors associated with healthcare systems. The consequences of not treating cancer pain may include reduced quality of life for patients with cancer (who now live longer than ever), functional decline, and increased psychological stress. Early analgesic intervention for cancer pain may reduce the risk of central sensitization and chronification of pain. To manage pain in oncology patients, clinicians should assess pain during regular follow-up visits using validated pain measurement tools and follow prescribing guidelines, if necessary referring patients with cancer to pain specialists. Many patients with cancer require opioids for pain relief. Pain associated with cancer may also relate to cancer treatments, such as chemotherapy-induced peripheral neuropathy. Many patients with cancer are what might be considered "special populations," in that they may be elderly, frail, comorbid, or have end-stage organ failure. Specific pain therapy guidelines for those populations are reviewed. Patients with cancer with a history of or active substance abuse disorder deserve pain control but may require close medical supervision. While much "treatment inertia" exists in cancer pain control, cancer pain can be safely and effectively managed and should be carried out to alleviate suffering and improve outcomes.

Background ACHEON is the first and largest cross-sectional analysis conducted to determine the current practices of pain management across Asia. This survey included responses from patients suffering from cancer pain in 10 countries or regions (China, Hong Kong, Indonesia, South Korea, Malaysia, Philippines, Singapore, Taiwan, Thailand, and Vietnam). Methods Patients were ⩾18 years (>20 years for Korean and Taiwanese patients) with cancer pain in the last month. Patients were recruited by random selection from patient associations, patient referrals, online panels, hospital intercepts or doctor referrals. Patients were asked “yes” or “no” statements or questions with a five-point Likert scale ranging from “agree completely” to “disagree completely”. Findings 1190 cancer patients (32% male, 68% female) with a mean age of 54 years were included. Moderate-to-severe pain (median score 6 [IQR 3]) was reported by 86% of patients, while overall median duration of pain was 12 months (IQR 19). Although most patients (83%) were asked about pain by physicians at every visit, 49% of patients reported no scale was used for pain assessment. Opioid use was confirmed in 53% (285/538) of patients who remembered the type of pain medication prescribed. In all, 81% of patients claimed that pain affected their daily living (86%), and concentration and focus (87%). Furthermore, 78% of respondents were unemployed with 42% discontinuing work due to cancer pain. Among employed patients, 70% reported that pain affected work. Interpretation Cancer pain is a debilitating condition creating significant social and economic burden for Asian patients. In general, the patients surveyed had poor quality of life. Importantly, no scale was used for pain assessment in 49% of the patients. Opioids were prescribed to some patients only. This survey indicated a critical need to enhance cancer pain management via adequate assessment and therapy optimisation.

Kok-Yuen Ho,1 Mohamed Abdul Hadi,2 Koravee Pasutharnchat,2 Kian-Hian Tan21Pain Management Centre, Raffles Hospital, 2Pain Management Centre, Singapore General Hospital, SingaporeBackground: Sacroiliac joint pain is a common cause of chronic low back pain. Different techniques for radiofrequency denervation of the sacroiliac joint have been used to treat this condition. However, results have been inconsistent because the variable sensory supply to the sacroiliac joint is difficult to disrupt completely using conventional radiofrequency. Cooled radiofrequency is a novel technique that uses internally cooled radiofrequency probes to enlarge lesion size, thereby increasing the chance of completely denervating the sacroiliac joint. The objective of this study was to evaluate the efficacy of cooled radiofrequency denervation using the SInergyTM cooled radiofrequency system for sacroiliac joint pain.Methods: The charts of 20 patients with chronic sacroiliac joint pain who had undergone denervation using the SInergyTM cooled radiofrequency system were reviewed at two years following the procedure. Outcome measures included the Numeric Rating Scale for pain intensity, Patient Global Impression of Change, and Global Perceived Effect for patient satisfaction.Results: Fifteen of 20 patients showed a significant reduction in pain (a decrease of at least three points on the Numeric Rating Scale). Mean Numeric Rating Scale for pain decreased from 7.4 ± 1.4 to 3.1 ± 2.5, mean Patient Global Impression of Change was "improved" (1.4 ± 1.5), and Global Perceived Effect was reported to be positive in 16 patients at two years following the procedure.Conclusion: Cooled radiofrequency denervation showed long-term efficacy for up to two years in the treatment of sacroiliac joint pain.Keywords: ablation, chronic low back pain, intervention, neurotomy, sacroiliitis

Chronic pain is a debilitating problem with significant impact on healthcare utilization in the US. Many chronic pain patients use complementary or alternative medicine (CAM) in addition to standard pharmacologic therapy.The aim of our study was to identify differences in the characteristics of usage of CAM for chronic pain control among several ethnic groups.We recruited 92 consecutive patients seeking treatment at the pain clinic and interviewed them using a questionnaire.The most common pain complaint was back pain (55.4%) and the mean pain duration for all chronic pain problems was 9.8 years. Approximately 81% of respondents were using or have used CAM before. The commonest CAM used by patients in our study included massage therapy, spiritual healing as well as the consumption of mineral and vitamin supplements. Sixty-three percent of them were satisfied with CAM treatment compared to 56% of patients who were satisfied with prescription therapy. However, there was no difference in the use of CAM among the different ethnic groups (P0.05).Our study demonstrates that CAM is used very frequently in patients with chronic pain. However, it did not show any ethnic or racial differences in CAM utilization.

Lysis of epidural adhesions is an interventional procedure performed to treat refractory low back pain or radicular pain due to epidural scarring. A 39-year-old female with a diagnosis of failed back surgery syndrome underwent lysis of epidural adhesions using a Racz catheter. She developed acute monoplegia of her right lower extremity immediately after the procedure. Radiographic imaging did not reveal an epidural hematoma. Motor and sensory function in the right lower limb returned after 5 days. Large volumes of fluid injected during neuroplasty could have caused transient nerve injury from compression within loculated epidural compartments.

Objective. This report describes a case of computed tomography (CT)-guided bilateral posteromedian transdiscal approach to the superior hypogastric plexus with neurolysis for treatment of intractable abdominal pain secondary to metastatic prostate cancer. The case is considered in relation to other approaches described in the literature. Design. Case presentation and literature review. Patients. An 83-year-old man with metastatic prostate cancer and intractable abdominal pain. Interventions. Computed tomography-guided bilateral posteromedian transdiscal neurolysis of the superior hypogastric plexus. Results. Pain reduction for intractable metastatic prostate cancer abdominal pain. Conclusions. Neurolysis of the superior hypogastric plexus is effective in treating metastatic prostate cancer abdominal pain. While there are significant risks to the CT-guided bilateral transdiscal approach to the superior hypogastric plexus, it may be used effectively as an alternative to navigate anatomic obstacles necessary to perform the neurolysis.

The piriformis muscle syndrome has been described in the literature since 1947 and accounts for 6-8% of patients presenting with buttock pain, which may variably be associated with sciatica. Through the years, there have been attempts to find safe and effective ways of managing this condition, whether through conservative treatment or with the use of interventional procedures. Several authors have reported injection techniques using the following: nerve stimulation; fluoroscopy with electromyography; and fluoroscopy with muscle stimulation. We aim to describe an injection method which is effective, simple, reproducible, easily available, and safe. This is the first report on the combined use of ultrasonography and motor stimulation in performing piriformis muscle injection. Our technique offers advantages such as: markedly decreased radiation exposure for both patient and doctor; improved visualization of sciatic nerve and surrounding muscles; improved portability; the possibility of being performed as an office-based procedure; and allows for an accurate confirmation of pain in the piriformis muscle with stimulation.

6531 Background: In order to implement more effective policies for cancer pain management, a better understanding of current practices and their effects on patients are needed. The ACHEON study was...

Rapid delivery of potent opioid to the systemic circulation is an important feature for the effective treatment of acute and acute-on-chronic breakthrough pain. The delivery of different opioids by the pulmonary route has been inconsistent, usually resulting in low bioavailability of the drug. Staccato® Fentanyl for Inhalation is a handheld inhaler producing a single metered dose of aerosolized fentanyl during a single inspiration. The aerosol is of high purity (≥98%) at a particle size (1 to 3.5 microns) shown to be best for pulmonary absorption.We conducted the study in healthy volunteers in 2 stages. In the crossover stage, 10 subjects received IV fentanyl 25 µg and inhaled fentanyl 25 µg on separate occasions. The dose escalation stage was a multidose, randomized, double-blind, placebo-controlled, single-period dose escalation study of inhaled fentanyl (50 to 300 µg). Serial blood sampling was performed over an 8-hour period after drug administration to determine the pharmacokinetic profile, and serial pupillometry was performed as a measure of pharmacodynamic effect.In the crossover stage the pharmacokinetic profiles of the inhaled and IV fentanyl showed similar peak arterial concentrations and areas under the curve. The time to maximum concentration was slightly shorter for the inhaled than IV fentanyl, 20.5 and 31.5 seconds, respectively. In the dose escalation stage the administration of repeated doses resulted in predictable, dose-dependent serum concentrations.This study has demonstrated that the pharmacokinetic profile of single doses of inhaled fentanyl is comparable to IV administration.

The objective of this systematic review was to evaluate the efficacy and tolerability of perioperative gabapentin administration for the control of acute postoperative pain. We searched Medline (1966–2006), the Cochrane Library (2006), Scopus, CINAHL and bibliographies from clinical trials and review articles. We included randomized controlled trials (RCTs) comparing gabapentin with inactive controls in surgical patients. Sixteen valid RCTs were included. Weighted mean difference (WMD) for postoperative pain intensity (0–100 mm visual analogue scale) was −16.55 mm at 6 h and −10.87 mm at 24 h for treatment with a single preoperative dose of gabapentin 1200 mg. Cumulative opioid consumption at 24 h was also significantly decreased with gabapentin (WMD, −27.90 mg). When gabapentin was administered at doses less than 1200 mg, pain intensity was also lower at 6 h (WMD, −22.43 mm) and 24 h (WMD, −13.18 mm). Cumulative 24 h opioid consumption was also lower (WMD, −7.25 mg). Gabapentin was associated with an increased risk of sedation (Peto OR 3.86; 95% CI 2.50–5.94) but less opioid-related side effects such as vomiting (Peto OR 0.58; 95% CI 0.39–0.86) and pruritus (Peto OR 0.27; 95% CI 0.10–0.74). In conclusion, gabapentin has an analgesic and opioid-sparing effect in acute postoperative pain management when used in conjunction with opioids.

Dessy R Emril1 Kok-Yuen Ho21Neurology Department, Syiah Kuala University/Dr Zainoel Abidin Hospital, Banda Aceh, Indonesia; 2Pain Management Centre, Raffles Hospital, SingaporeAbstract: Trigeminal neuralgia (TN) is a neuropathic pain condition affecting the face. It has a significant impact on the quality of life and physical function of patients. Evidence suggests that the likely etiology is vascular compression of the trigeminal nerve leading to focal demyelination and aberrant neural discharge. Secondary causes such as multiple sclerosis or brain tumors can also produce symptomatic TN. Treatment must be individualized to each patient. Carbamazepine remains the drug of choice in the first-line treatment of TN. Minimally invasive interventional pain therapies and surgery are possible options when drug therapy fails. Younger patients may benefit from microvascular decompression. Elderly patients with poor surgical risk may be more suitable for percutaneous trigeminal nerve rhizolysis. The technique of radiofrequency rhizolysis of the trigeminal nerve is described in detail in this review.Keywords: interventional treatment, minimally invasive, pain management, radiofrequency rhizolysis, trigeminal neuralgia&nbsp