A prospective study of long-term intrathecal morphine in the management of chronic nonmalignant pain

SPIDOL study protocol for the assessment of intrathecal ziconotide antalgic efficacy for severe refractory neuropathic pain due to spinal cord lesions

RATIONALE

Central neuropathic pain resulting from spinal cord injury is notoriously debilitating and difficult to treat with few currently available treatments. A novel molecule with intrathecal administration: Ziconotide has been approved for treatment of refractory neuropathic pain in general. It acts as a presynaptic calcium channel blocker. A pilot study has shown its potential in SCI neuropathic pain patients.

OBJECTIVE

The aim of this study is to determine the long-term (6 months) efficacy of chronic intrathecal ziconotide for the treatment of neuropathic SCI pain.

STUDY DESIGN

Multicenter, Randomized, Comparative, Placebo controlled, Double blind clinical trial, with a crossover of random alternated periods of 6 months (placebo or ITZ) for a total of 15 months including a total of 44 patients.

STUDY POPULATION

• Patients with SCI of various etiologies exhibiting neuropathic pain refractory to non-invasive treatments. • > 18 years.

INTERVENTION

Intrathecal administration of ziconotide via an implanted pump.

STUDY OUTCOMES

Primary study outcome Difference in pain intensity for all patients between effective treatment and placebo periods. Secondary study outcomes 1. Continuous evaluation of pain intensity. 2. Percentage of patients with at least 30% of pain reduction. 3. Satisfaction level of the patient pain relief. 4. Declarations of serious adverse events. 5. Duration and intensity of spontaneous and provoked pain. 6. Quality of life. 7. Patient global impression of change. 8. Quantification of daily dosages of analgesic drug intake. 9. Long term memory and neurocognitive effects. 10. Assessment of the patient's physical and emotional distress. NATURE AND EXTENT OF THE BURDEN AND RISKS ASSOCIATED WITH PARTICIPATION, BENEFIT, AND GROUP RELATEDNESS: Participation in this study is in accordance with current treatment protocols for SCI neuropathic pain in France therefore it proposes a treatment that would currently be considered regular practice even though no RCT evidence is yet available. The study gives patients the advantage of directly testing versus placebo a treatment that otherwise entails significant constraints. A Data Safety Monitoring board (DSMB) will be created for continuous safety analysis. Furthermore, patients will be followed in specialized pain centers offering the possibility of continuing their treatment after the study period.

Optimizing Preoperative Chronic Pain Management in Elective Spine Surgery Patients: A Narrative Review of Outcomes with Opioid and Adjuvant Pain Therapies

» Chronic preoperative opioid use negatively affects outcomes after spine surgery, with increased complications and reoperations, longer hospital stays, decreased return-to-work rates, worse patient-reported outcomes, and a higher risk of continued opioid use postoperatively.» The definition of chronic opioid use is not consistent across studies, and a more specific and consistent definition will aid in stratifying patients and understanding their risk of inferior outcomes.» Preoperative weaning periods and maximum dose thresholds are being established, which may increase the likelihood of achieving a meaningful improvement after surgery, although higher level evidence studies are needed.» Spinal cord stimulators and intrathecal drug delivery devices are increasingly used to manage chronic back pain and are equivalent or perhaps even superior to opioid treatment, although few studies exist examining how patients with these devices do after subsequent spine surgery.» Further investigation is needed to determine whether a true mechanistic explanation exists for spine-related analgesia related to spinal cord stimulators and intrathecal drug delivery devices.

Myth and Truth in Opioid Consumption with Intrathecal Morphine Pump Implantation in Chronic Pain: A Retrospective Cohort Study with Claims Database in South Korea

OBJECTIVE

To investigate the opioid consumption and the healthcare resource utilization in patients with the intrathecal drug delivery system (IDDS) therapy and the comprehensive medical management (CMM) alone.

DESIGN

A retrospective cohort study with a customized claims database.

SETTING

In a university-based hospital.

SUBJECTS

Patients with complex regional pain syndrome, post-laminectomy syndrome, and fibromyalgia.

METHODS

Using propensity score matching (1:3), we selected patients with morphine infusion through IDDS (IDDS group) and CMM alone (CMM group). The primary endpoints were comparisons of average morphine equivalents daily dosages (MEDD, mg/day) for 6 and 12 months from an index date. The number of emergency room (ER) visits and hospitalizations and the total medical expenditures were compared as secondary outcomes.

RESULTS

In total, 82 patients (N = 23 in the IDDS group and N = 59 in the CMM group) were analyzed. Although a 6-month average MEDD did not reach statistical significance, a 12-month average MEDD was significantly decreased in the IDDS group compared to the CMM group (53.2 ± 46.3 vs 123.9 ± 176.4, respectively; P = 0.008). ER visits were more frequent in the IDDS group than the CMM group at baseline (5.4 vs 0.5, respectively; P = .002), which was maintained for 12 months (P < 0.001). Otherwise, the number of hospitalization and the medical expenditures for pain management were not different between the groups for 12 months.

CONCLUSIONS

The combined IDDS therapy had some benefits in reducing opioid consumption for 1-year follow-up compared to the CMM alone in chronic noncancer pain patients.

The American Society of Pain and Neuroscience (ASPN) Evidence-Based Clinical Guideline of Interventional Treatments for Low Back Pain

Introduction

Painful lumbar spinal disorders represent a leading cause of disability in the US and worldwide. Interventional treatments for lumbar disorders are an effective treatment for the pain and disability from low back pain. Although many established and emerging interventional procedures are currently available, there exists a need for a defined guideline for their appropriateness, effectiveness, and safety.

Objective

The ASPN Back Guideline was developed to provide clinicians the most comprehensive review of interventional treatments for lower back disorders. Clinicians should utilize the ASPN Back Guideline to evaluate the quality of the literature, safety, and efficacy of interventional treatments for lower back disorders.

Methods

The American Society of Pain and Neuroscience (ASPN) identified an educational need for a comprehensive clinical guideline to provide evidence-based recommendations. Experts from the fields of Anesthesiology, Physiatry, Neurology, Neurosurgery, Radiology, and Pain Psychology developed the ASPN Back Guideline. The world literature in English was searched using Medline, EMBASE, Cochrane CENTRAL, BioMed Central, Web of Science, Google Scholar, PubMed, Current Contents Connect, Scopus, and meeting abstracts to identify and compile the evidence (per section) for back-related pain. Search words were selected based upon the section represented. Identified peer-reviewed literature was critiqued using United States Preventive Services Task Force (USPSTF) criteria and consensus points are presented.

Results

After a comprehensive review and analysis of the available evidence, the ASPN Back Guideline group was able to rate the literature and provide therapy grades to each of the most commonly available interventional treatments for low back pain.

Conclusion

The ASPN Back Guideline represents the first comprehensive analysis and grading of the existing and emerging interventional treatments available for low back pain. This will be a living document which will be periodically updated to the current standard of care based on the available evidence within peer-reviewed literature.

Acute morphine administration, morphine dependence, and naloxone-induced withdrawal syndrome affect the resting-state functional connectivity and local field potentials of the rat prefrontal cortex

Opiates are among the widely abused substances worldwide. Also, the clinical use of opioids can cause unwanted and potentially severe consequences such as developing tolerance and dependence. This study simultaneously measured the changes induced after morphine dependence and naloxone-induced withdrawal syndrome on the resting-state functional connectivity (rsFC) and local field potential (LFP) power in the prefrontal cortex of the rat. The obtained results revealed that acute morphine administration significantly increased the LFP power in all frequency bands, as well as the rsFC strength of the prefrontal cortex, and naloxone injection reversed this effect. In contrast, chronic morphine administration reduced neural activity and general correlation values in intrinsic signals, as well as the LFP power in all frequency bands. In morphine-dependent rats, after each morphine administration, the LFP power in all frequency bands and the rsFC strength of the prefrontal cortex were increased, and these effects were further enhanced after naloxone precipitated withdrawal syndrome. The present study concludes that general correlation merely reflects the field activity of the local cortices imaged.

A safety review of approved intrathecal analgesics for chronic pain management

Introduction: Intrathecal (IT) drug therapy is an effective treatment option for patients with chronic pain of malignant or nonmalignant origin, with an established safety profile and fewer adverse effects compared to oral or parenteral pain medications. Morphine (a μ-opioid receptor agonist) and ziconotide (a non-opioid calcium channel antagonist) are the only IT agents approved by the U.S. Food and Drug Administration for the treatment of chronic pain. Although both are considered first-line IT therapies, each drug has unique properties and considerations.Areas Covered: This review will evaluate the pivotal trials that established the use of morphine and ziconotide as first-line IT therapy for patients with chronic pain, as well as safety and efficacy data generated from various retrospective and prospective studies.Expert Opinion: Morphine and ziconotide are effective IT therapies for patients with chronic malignant or nonmalignant pain that is refractory to other interventions. IT ziconotide is recommended as a first-line therapy due to its efficacy and avoidance of many adverse effects commonly associated with opioids. The use of IT morphine is also considered first-line; however, the risks of respiratory depression, withdrawal with drug discontinuation or pump malfunction, and the development of tolerance require careful patient selection and management.

Effect of First-Line Ziconotide Intrathecal Drug Therapy for Neuropathic Pain on Disability, Emotional Well-Being, and Pain Catastrophizing

BACKGROUND

Previous studies have shown decreased pain scores with ziconotide as a first-line agent for intrathecal drug therapy (IDT). Subset analysis suggests that patients with neuropathic pain have greater improvement. We prospectively examine the role of first-line ziconotide IDT on the tridimensional pain experience in ziconotide IDT-naive patients with neuropathic pain.

METHODS

We included patients who underwent a successful ziconotide trial and were scheduled for standard-of-care IDT pump placement. Scores were collected at baseline and latest follow-up for the following measures: Short-Form 36 (SF-36), Oswestry Disability Index (ODI), Beck Depression Inventory, and Pain Catastrophizing Scale (PCS). Numeric rating scale (NRS) scores were also collected at each follow-up visit to monitor patients' pain levels and to guide ziconotide dose titration. Responders were identified as patients who had a previously established minimum clinically important difference of a ≥1.2-point reduction in NRS current scores.

RESULTS

Eleven of 14 patients completed long-term follow-up. There were 7 responders based on NRS minimum clinically important difference. At a mean (±standard error of the mean) follow-up of 10.91 ± 0.70 months, SF-36 emotional well-being (P = 0.04), SF-36 pain (P = 0.02), and ODI (P = 0.03) significantly improved for the entire cohort and in responders (SF-36 emotional well-being, P = 0.01; SF-36 pain, P = 0.04; ODI, P = 0.02). PCS-Rumination (P = 0.02), PCS-Helplessness (P = 0.02), and PCS-Total (P = 0.003) scores improved significantly for responders only.

CONCLUSIONS

We show that ziconotide IDT improves pain as well as emotional components and function. Our study adds prospective evidence to the literature on IDT for neuropathic pain, specifically its role in improving disability, emotional well-being, and catastrophizing.

Zero-order drug delivery: State of the art and future prospects

Pharmaceutical drugs are an important part of the global healthcare system, with some estimates suggesting over 50% of the world's population takes at least one medication per day. Most drugs are delivered as immediate-release formulations that lead to a rapid increase in systemic drug concentration. Although these formulations have historically played an important role, they can be limited by poor patient compliance, adverse side effects, low bioavailability, or undesirable pharmacokinetics. Drug delivery systems featuring first-order release kinetics have been able to improve pharmacokinetics but are not ideal for drugs with short biological half-lives or small therapeutic windows. Zero-order drug delivery systems have the potential to overcome the issues facing immediate-release and first-order systems by releasing drug at a constant rate, thereby maintaining drug concentrations within the therapeutic window for an extended period of time. This release profile can be used to limit adverse side effects, reduce dosing frequency, and potentially improve patient compliance. This review covers strategies being employed to attain zero-order release or alter traditionally first-order release kinetics to achieve more consistent release before discussing opportunities for improving device performance based on emerging materials and fabrication methods.

Patients' perception about opioids and addiction in South Korea

Background

Chronic pain affects approximately 22% of the world’s population. Opioids can be useful in chronic pain management. However, some patients have negative perception of opioids. The purpose of this research was to evaluate patients’ perception about opioids and investigate problems associated with prescribing and taking opioids in South Korea.

Methods

Patients who visited a pain clinic in 14 university hospitals of South Korea from September through October 2018 were asked to complete anonymous questionnaires about taking opioids.

Results

Of the 368 patients that were surveyed (female 53.3%, male 46.7%), 56.8% were prescribed opioids. In the opioid group, 92.8% patients had heard of opioids from their doctor and 72.6% of them had a positive perception about opioids. The side effects associated with opioid use were constipation (35.4%), dizziness (24.6%), nausea and vomiting (17.4%), dysuria (6.2%), and addiction (2.0%). In the no opioid group, the primary sources of information about opioids were doctors (49.2%), mass media (30.8%), and the internet (16.2%). The main reasons why 39.0% patients did not take opioids were fear of addiction (57.7%) and side effects (38.5%). There were 71.5% and 60.9% patients in the opioid and no opioid group, respectively, who wished to take opioids when their numeric rating scale pain score was ≥ 7.

Conclusions

Perception of opioids among patients who take them was either neutral or positive. However, 39.0% patients who have not been prescribed opioids did not want an opioid prescription, citing fear of addiction and side effects as the primary reasons.

Economic Inequities in the Application of Neuromodulation Devices

Background  There is a significant upfront cost for the use of neuromodulation devices. The high cost of these devices may lead to disproportionate application in geographical regions with different levels of financial resources. The purpose of this study was to determine if there is geographic based economic inequity in the application of neuromodulation devices in the United States. Methods  Population and average household income data by county from the year 2010 were obtained from publicly available databases on the US Census website. The number of stimulators sold by county in the years 2009 and 2010 were provided by two of the four neuromodulation companies with commercially available products. Pearson correlation and t-test statistics were performed. Results  Of the 3142 U.S. counties analyzed, only 689 placed neuromodulation devices during this period of time. There was a difference in average household income between counties with device implants ($49,663) and counties with no device implants ($41,314), which was statistically significant (p<0.001). Conclusion  Analysis of neuromodulation devices placed in 2009 and 2010 from 50% of neuromodulation companies demonstrated that there was an income disparity between counties in which implantation of devices occurred and counties in which there were no device implantations.

Intrathecal Therapy for Chronic Pain: A Review of Morphine and Ziconotide as Firstline Options

Objectives

To evaluate the evidence for morphine and ziconotide as firstline intrathecal (IT) analgesia agents for patients with chronic pain.

Methods

Medline was searched (through July 2017) for “ziconotide” or “morphine” AND “intrathecal” AND “chronic pain,” with results limited to studies in human populations.

Results

The literature supports the use of morphine (based primarily on noncontrolled, prospective, and retrospective studies) and ziconotide (based on randomized controlled trials and prospective observational studies) as first-choice IT therapies. The 2016 Polyanalgesic Consensus Conference (PACC) guidelines recommended both morphine and ziconotide as firstline IT monotherapy for localized and diffuse chronic pain of cancer-related and non–cancer-related etiologies; however, one consensus point emphasized ziconotide use, unless contraindicated, as firstline IT therapy in patients with chronic non–cancer-related pain. Initial IT therapy choice should take into consideration individual patient characteristics (e.g., pain location, response to previous therapies, comorbid medical conditions, psychiatric history). Trialing is recommended to assess medication efficacy and tolerability. For both morphine and ziconotide, the PACC guidelines recommend conservative initial dosing strategies. Due to its narrow therapeutic window, ziconotide requires careful dose titration. Ziconotide is contraindicated in patients with a history of psychosis. IT morphine administration may be associated with serious side effects (e.g., respiratory depression, catheter tip granuloma), require dose increases, and cause dependence over time.

Conclusion

Based on the available evidence, morphine and ziconotide are recommended as firstline IT monotherapy for cancer-related and non–cancer-related pain. The choice of first-in-pump therapy should take into consideration patient characteristics and the advantages and disadvantages of each medication.

Managing Chronic Non-Malignant Pain in the Elderly: Intrathecal Therapy

Intrathecal drug delivery (IDD) was first described in 1981 by Onofrio, who used a pump for continuous and intrathecal delivery of morphine to treat cancer pain. Over the following four decades, many reports supported this treatment method with implanted pumps for cancer and non-cancer pain. To date, more than 300,000 pumps for pain therapy and spasticity have been implanted worldwide. This article reviews current knowledge regarding intrathecal opioid therapy, focusing particularly on the use of IDD in elderly patients. Current literature is presented, and the arguments in favor of and against this therapy in elderly patients are discussed.

Contemporary concepts of pain surgery

Pain surgery is one of the historic foundations of neurological surgery. The authors present a review of contemporary concepts in surgical pain management, with reference to past successes and failures, what has been learned as a subspecialty over the past 50 years, as well as a vision for current and future practice. This subspecialty confronts problems of cancer pain, nociceptive pain, and neuropathic pain. For noncancer pain, ablative procedures such as dorsal root entry zone lesions and rhizolysis for trigeminal neuralgia (TN) should continue to be practiced. Other procedures, such as medial thalamotomy, have not been proven effective and require continued study. Dorsal rhizotomy, dorsal root ganglionectomy, and neurotomy should probably be abandoned. For cancer pain, cordotomy is an important and underutilized method for pain control. Intrathecal opiate administration via an implantable system remains an important option for cancer pain management. While there are encouraging results in small case series, cingulotomy, hypophysectomy, and mesencephalotomy deserve further detailed analysis. Electrical neuromodulation is a rapidly changing discipline, and new methods such as high-frequency spinal cord stimulation (SCS), burst SCS, and dorsal root ganglion stimulation may or may not prove to be more effective than conventional SCS. Despite a history of failure, deep brain stimulation for pain may yet prove to be an effective therapy for specific pain conditions. Peripheral nerve stimulation for conditions such as occipital neuralgia and trigeminal neuropathic pain remains an option, although the quality of outcomes data is a challenge to these applications. Based on the evidence, motor cortex stimulation should be abandoned. TN is a mainstay of the surgical treatment of pain, particularly as new evidence and insights into TN emerge. Pain surgery will continue to build on this heritage, and restorative procedures will likely find a role in the armamentarium. The challenge for the future will be to acquire higher-level evidence to support the practice of surgical pain management.

Role of primary care physicians in intrathecal pain management: a narrative review of the literature

OBJECTIVES

The majority of patients seeking medical care for chronic pain consult a primary care physician (PCP). Because systemic opioids are commonly prescribed to patients with chronic pain, PCPs are attempting to balance the competing priorities of providing adequate pain relief while reducing risks for opioid misuse and overdose. It is important for PCPs to be aware of pain management strategies other than systemic opioid dose escalation when patients with chronic pain fail to respond to conservative therapies and to initiate a multimodal treatment plan.

METHODS

The Medline database and evidence-based treatment guidelines were searched to identify publications on intrathecal (IT) therapy for the management of chronic pain. Selection of publications relevant to PCPs was based on the authors' clinical and research expertise.

RESULTS

IT administration delivers analgesic medication directly into the cerebrospinal fluid, avoiding first-pass effect and bypassing the blood-brain barrier, thereby requiring lower medication doses. Morphine, a µ-opioid receptor agonist, and ziconotide, a non-opioid, selective N-type calcium channel blocker, are the only analgesics approved by the US Food and Drug Administration to treat chronic refractory pain by the IT route. Patients who are potential candidates for IT therapy may benefit from evaluation by an interventional pain physician. PCPs can play an important role in patient selection and referral for IT therapy and provide ongoing collaborative care for patients receiving IT therapy, including monitoring for efficacy and adverse events and facilitating communication with the treating specialist.

CONCLUSIONS

Collaboration between PCPs and pain specialists may improve outcomes of and patient satisfaction with IT therapy and other interventional treatments.

Retrospective analysis of the financial break-even point for intrathecal morphine pump use in Korea

Background

The high cost of intrathecal morphine pump (ITMP) implantation may be the main obstacle to its use. Since July 2014, the Korean national health insurance (NHI) program began paying 50% of the ITMP implantation cost in select refractory chronic pain patients. The aims of this study were to investigate the financial break-even point and patients' satisfaction in patients with ITMP treatment after the initiation of the NHI reimbursement.

Methods

We collected data retrospectively or via direct phone calls to patients who underwent ITMP implantation at a single university-based tertiary hospital between July 2014 and May 2016. Pain severity, changes in the morphine equivalent daily dosage (MEDD), any adverse events, and patients' satisfaction were determined. We calculated the financial break-even point of ITMP implantation via investigating the patient's actual medical costs and insurance information.

Results

During the studied period, 23 patients received ITMP implantation, and 20 patients were included in our study. Scores on an 11-point numeric rating scale (NRS) for pain were significantly reduced compared to the baseline value (P < 0.001). The MEDD before ITMP implantation was 0.59 [IQR: 0.55–0.82]. The total MEDD increased steadily to 0.77 [IQR: 0.53–1.08] at 1 year, which was 126% of the baseline (P < 0.001). More than a half (60%) responded that the ITMP therapy was somewhat satisfying. The financial break-even point was 28 months for ITMP treatment after the NHI reimbursement policy.

Conclusions

ITMP provided effective chronic pain management with improved satisfaction and reasonable financial break-even point of 28 months with 50% financial coverage by NHI program.

Current and Future Issues in the Development of Spinal Agents for the Management of Pain

Targeting analgesic drugs for spinal delivery reflects the fact that while the conscious experience of pain is mediated supraspinally, input initiated by high intensity stimuli, tissue injury and/or nerve injury is encoded at the level of the spinal dorsal horn and this output informs the brain as to the peripheral environment. This encoding process is subject to strong upregulation resulting in hyperesthetic states and downregulation reducing the ongoing processing of nociceptive stimuli reversing the hyperesthesia and pain processing. The present review addresses the biology of spinal nociceptive processing as relevant to the effects of intrathecally-delivered drugs in altering pain processing following acute stimulation, tissue inflammation/injury and nerve injury. The review covers i) the major classes of spinal agents currently employed as intrathecal analgesics (opioid agonists, alpha 2 agonists; sodium channel blockers; calcium channel blockers; NMDA blockers; GABA A/B agonists; COX inhibitors; ii) ongoing developments in the pharmacology of spinal therapeutics focusing on less studied agents/targets (cholinesterase inhibition; Adenosine agonists; iii) novel intrathecal targeting methodologies including gene-based approaches (viral vectors, plasmids, interfering RNAs); antisense, and toxins (botulinum toxins; resniferatoxin, substance P Saporin); and iv) issues relevant to intrathecal drug delivery (neuraxial drug distribution), infusate delivery profile, drug dosing, formulation and principals involved in the preclinical evaluation of intrathecal drug safety.

The conversion challenge: From intrathecal to oral morphine

Numerous articles have described the methodologies used and outcomes achieved with the intrathecal (IT) administration of morphine for pain. However, only one case report has been published that describes converting a patient’s IT morphine to an oral regimen. This case report describes the experience of converting a patient’s IT morphine to oral morphine and discusses the scarcity of published data to validate suggested equianalgesic intraspinal morphine recommendations. The calculated equianalgesic oral to IT ratio in this case was 12:1. This is substantially lower than the 300:1 ratio published by Krames and the 90:1 ratio employed by a commercially available software program for calculating equianalgesic opioid doses. We recommend caution when applying existing guidelines for conversion of morphine from an IT to an oral regimen.

Total pancreatectomy with islet cell transplantation vs intrathecal narcotic pump infusion for pain control in chronic pancreatitis

AIM: To evaluate pain control in chronic pancreatitis patients who underwent total pancreatectomy with islet cell transplantation or intrathecal narcotic pump infusion.

METHODS: We recognized 13 patients who underwent intrathecal narcotic pump (ITNP) infusion and 57 patients who underwent total pancreatectomy with autologous islet cell transplantation (TP + ICT) for chronic pancreatitis (CP) pain control between 1998 and 2008 at Indiana University Hospital. All patients had already failed multiple other modalities for pain control and the decision to proceed with either intervention was made at the discretion of the patients and their treating physicians. All patients were evaluated retrospectively using a questionnaire inquiring about their pain control (using a 0-10 pain scale), daily narcotic dose usage, and hospital admission days for pain control before each intervention and during their last follow-up.

RESULTS: All 13 ITNP patients and 30 available TP + ICT patients were evaluated. The mean age was approximately 40 years in both groups. The median duration of pain before intervention was 6 years and 7 years in the ITNP and TP + ICT groups, respectively. The median pain score dropped from 8 to 2.5 (on a scale of 0-10) in both groups on their last follow up. The median daily dose of narcotics also decreased from 393 mg equivalent of morphine sulfate to 8 mg in the ITNP group and from 300 mg to 40 mg in the TP + ICT group. No patient had diabetes mellitus (DM) before either procedure whereas 85% of those who underwent pancreatectomy were insulin dependent on their last evaluation despite ICT.

CONCLUSION: ITNP and TP + ICT are comparable for pain control in patients with CP however with high incidence of DM among those who underwent TP + ICT. Prospective comparative studies and longer follow up are needed to better define treatment outcomes.

Trends in Pain Medicine Liability

BACKGROUND

The authors examined changes in the frequency of pain medicine malpractice claims and associated treatment modalities and outcomes over time.

METHODS

The authors analyzed trends in pain medicine claims from 1980 to 2012 in the Anesthesia Closed Claims Project database by binary logistic regression on year of event. Pain procedures in claims from 2000 to 2012 were compared with the proportion of pain procedures reported to the National Anesthesia Clinical Outcomes Registry in 2010-2014.

RESULTS

Malpractice claims for pain medicine increased from 3% of 2,966 total malpractice claims in the Anesthesia Closed Claims Project database in 1980-1989 to 18% of 2,743 anesthesia claims in 2000-2012 (odds ratio [OR], 1.088 per year; 95% CI, 1.078 to 1.098; P < 0.001). Outcomes in pain claims became more severe over time, with increases in death and permanent disabling injury (OR, 1.094 per year; P < 0.001). Nonneurolytic cervical injections increased to 27% of pain claims in 2000-2012 (OR, 1.054; P < 0.001), whereas National Anesthesia Clinical Outcomes Registry demonstrates that lumbar injections are a more common procedure. Claims associated with medication management increased to 17% of pain claims in 2000-2012 (OR, 1.116 per year; P < 0.001).

CONCLUSIONS

Pain medicine claims have increased over time and have increased in severity. Claims related to cervical procedures were out of proportion to the frequency with which they are performed. These liability findings suggest that pain specialists should aggressively continue the search for safer and more effective therapies.

Dual Effect of Ziconotide in Primary Erythromelalgia

Erythromelalgia (EM) is a rare disabling clinical syndrome more commonly known to affect the lower extremities. There is no single effective treatment for this disease that often requires a multidisciplinary approach. Herein, we report the case of a 31-year-old woman affected by primary erythromelalgia who was successfully treated with intrathecal Ziconotide. We also observed an unexpected result following therapy with Ziconotide. The legs and feet of the patient that at the time of admission were swollen and tumefied dramatically improved after one week of the drug administration.

Failed back surgery syndrome: a suggested algorithm of care

Failed back surgery syndrome (FBSS) is a complex condition which can be very difficult to treat. In this article, we propose a pragmatic algorithm for the management of the syndrome. The management of this condition should include a comprehensive initial assessment to rule out treatable cause, pharmacological optimisation, psychological techniques and neuromodulation. There is good evidence to support early application of conventional spinal cord stimulation for FBSS patients suffering from predominant buttock and leg pain. Emerging techniques in neuromodulation such as high-frequency spinal cord stimulation, peripheral nerve field stimulation and dorsal root ganglion stimulation hold promise for the future, but long-term outcome regarding efficacy and safety is not yet established. Intrathecal drug delivery systems should also be considered in those who are unsuitable or unresponsive to neuromodulation and still warrant further treatment. However, the long-term outcome may not be as good as with other treatments mentioned above.

Interventional Therapies for Chronic Low Back Pain: A Focused Review (Efficacy and Outcomes)

Context:

Lower back pain is considered to be one of the most common complaints that brings a patient to a pain specialist. Several modalities in interventional pain management are known to be helpful to a patient with chronic low back pain. Proper diagnosis is required for appropriate intervention to provide optimal benefits. From simple trigger point injections for muscular pain to a highly complex intervention such as a spinal cord stimulator are very effective if chosen properly. The aim of this article is to provide the reader with a comprehensive reading for treatment of lower back pain using interventional modalities.

Evidence Acquisition:

Extensive search for published literature was carried out online using PubMed, Cochrane database and Embase for the material used in this manuscript. This article describes the most common modalities available to an interventional pain physician along with the most relevant current and past references for the treatment of lower back pain. All the graphics and images were prepared by and belong to the author.

Results:

This review article describes the most common modalities available to an interventional pain physician along with the most relevant current and past references for the treatment of lower back pain. All the graphics and images belong to the author. Although it is beyond the scope of this review article to include a very detailed description of each procedure along with complete references, a sincere attempt has been made to comprehensively cover this very complex and perplexing topic.

Conclusion:

Lower back pain is a major healthcare issue and this review article will help educate the pain practitioners about the current evidence based treatment options.

The Relationship Between the Mechanisms of Action and Safety Profiles of Intrathecal Morphine and Ziconotide: A Review of the Literature

OBJECTIVE

To better characterize safety profiles associated with the intrathecal (IT) administration of morphine and ziconotide and discuss how they relate to mechanisms of action.

METHODS

Published data were evaluated to identify potential relationships between safety profiles of IT morphine and IT ziconotide and their mechanisms of action.

RESULTS

Potentially severe and clinically relevant adverse events (AEs) associated with IT morphine include respiratory depression, tolerance, and granuloma formulation, whereas IT ziconotide is associated with neuropsychiatric AEs, such as cognitive impairment, hallucinations, and changes in mood or consciousness, particularly with high doses and rapid titration. AEs associated with these IT therapies may result from spread of the medication out of the IT space into areas of the central and peripheral nervous systems and systemic circulation. AEs that occur usually can be managed and, in some cases, prevented. To mitigate risk, patients' histories should be reviewed to identify potential complicating factors (e.g., obesity or other risk factors for respiratory dysfunction in patients receiving IT morphine; a history of psychosis in patients receiving IT ziconotide). Also, treatment should be initiated at a low dose, titrated slowly, and patients should be closely monitored during treatment.

CONCLUSIONS

IT morphine and IT ziconotide are approved by the US Food and Drug Administration for patients who do not respond to less invasive treatments, but the safety profiles of each may make them more or less appropriate for certain patient populations.

Ziconotide

Questions from patients about pain conditions and analgesic pharmacotherapy and responses from authors are presented to help educate patients and make them more effective self-advocates. The topics addressed in this issue are ziconotide, a novel approach to pain management that is derived from a snail toxin, its uses and possible side effects.

Interventional management of neuropathic pain: NeuPSIG recommendations

Neuropathic pain (NP) is often refractory to pharmacologic and noninterventional treatment. On behalf of the International Association for the Study of Pain Neuropathic Pain Special Interest Group, the authors evaluated systematic reviews, clinical trials, and existing guidelines for the interventional management of NP. Evidence is summarized and presented for neural blockade, spinal cord stimulation (SCS), intrathecal medication, and neurosurgical interventions in patients with the following peripheral and central NP conditions: herpes zoster and postherpetic neuralgia (PHN); painful diabetic and other peripheral neuropathies; spinal cord injury NP; central poststroke pain; radiculopathy and failed back surgery syndrome (FBSS); complex regional pain syndrome (CRPS); and trigeminal neuralgia and neuropathy. Due to the paucity of high-quality clinical trials, no strong recommendations can be made. Four weak recommendations based on the amount and consistency of evidence, including degree of efficacy and safety, are: 1) epidural injections for herpes zoster; 2) steroid injections for radiculopathy; 3) SCS for FBSS; and 4) SCS for CRPS type 1. Based on the available data, we recommend not to use sympathetic blocks for PHN nor radiofrequency lesions for radiculopathy. No other conclusive recommendations can be made due to the poor quality of available data. Whenever possible, these interventions should either be part of randomized clinical trials or documented in pain registries. Priorities for future research include randomized clinical trials, long-term studies, and head-to-head comparisons among different interventional and noninterventional treatments.

Continuous Intrathecal Infusion of Ziconotide for Treatment of Chronic Malignant and Nonmalignant Pain Over 12 Months: A Prospective, Open-label Study

Objectives.  This study aims to assess the safety and efficacy of long-term intrathecal (IT) ziconotide infusion. Materials and Methods.  In this prospective study, 155 patients with severe chronic pain (48 with malignant pain, 107 with nonmalignant pain) who had been responsive to short-term IT ziconotide in a double-blind, placebo-controlled study received long-term, open-label IT ziconotide monotherapy. Efficacy assessments included the mean percentage change on the visual analog scale of pain intensity from baseline in the study of origin; safety was monitored by adverse event (AE) reports, periodic laboratory tests, and vital sign measurements. Results.  At the last available observation, the visual analog scale of pain intensity scores had decreased by a mean of 36.9% from baseline in the short-term trial (N = 144; 95% CI: 30.1-43.7%; p < 0.0001). The mean IT ziconotide dose remained stable over 12 months in the 31 patients who participated in the study for ≥ one year. Ziconotide-related AEs were reported in 147 out of 155 patients (94.8%); 39.4% of patients discontinued treatment because of AEs, the majority of which were considered ziconotide related. Conclusions.  Ziconotide IT monotherapy provided patients with analgesia for 12 months in this open-label study, with an acceptable benefit/risk profile and no evidence of tolerance.

Intrathecal drug administration in chronic pain syndromes

Chronic pain may recur after initial response to strong opioids in both patients with cancer and patients without cancer or therapy may be complicated by intolerable side effects. When minimally invasive interventional pain management techniques also fail to provide satisfactory pain relief, continuous intrathecal analgesic administration may be considered. Only 3 products have been officially approved for long-term intrathecal administration: morphine, baclofen, and ziconotide. The efficacy of intrathecal ziconotide for the management of patients with severe chronic refractory noncancer pain was illustrated in 3 placebo-controlled trials. A randomized study showed this treatment option to be effective over a short follow-up period for patients with pain due to cancer or AIDS. The efficacy of intrathecal opioid administration for the management of chronic noncancer pain is mainly derived from prospective and retrospective noncontrolled trials. The effect of intrathecal morphine administration in patients with pain due to cancer was compared with oral or transdermal treatment in a randomized controlled trial, which found better pain control and fewer side effects with intrathecal opioids. Other evidence is derived from cohort studies. Side effects of chronic intrathecal therapy may either be technical (catheter or pump malfunction) or biological (infection). The most troublesome complication is, however, the possibility of granuloma formation at the catheter tip that may induce neurological damage. Given limited studies, the evidence for intrathecal drug administration in patients suffering from cancer-related pain is more compelling than that of chronic noncancer pain.

Long-term opioid treatment of chronic nonmalignant pain: unproven efficacy and neglected safety?

BACKGROUND

For the past 30 years, opioids have been used to treat chronic nonmalignant pain. This study tests the following hypotheses: (1) there is no strong evidence-based foundation for the conclusion that long-term opioid treatment of chronic nonmalignant pain is effective; and (2) the main problem associated with the safety of such treatment - assessment of the risk of addiction - has been neglected.

METHODS

Scientometric analysis of the articles representing clinical research in this area was performed to assess (1) the quality of presented evidence (type of study); and (2) the duration of the treatment phase. The sufficiency of representation of addiction was assessed by counting the number of articles that represent (1) editorials; (2) articles in the top specialty journals; and (3) articles with titles clearly indicating that the addiction-related safety is involved (topic-in-title articles).

RESULTS

Not a single randomized controlled trial with opioid treatment lasting >3 months was found. All studies with a duration of opioid treatment ≥6 months (n = 16) were conducted without a proper control group. Such studies cannot provide the consistent good-quality evidence necessary for a strong clinical recommendation. There were profound differences in the number of addiction articles related specifically to chronic nonmalignant pain patients and to opioid addiction in general. An inadequate number of chronic pain-related publications were observed with all three types of counted articles: editorials, articles in the top specialty journals, and topic-in-title articles.

CONCLUSION

There is no strong evidence-based foundation for the conclusion that long-term opioid treatment of chronic nonmalignant pain is effective. The above identified signs indicating neglect of addiction associated with the opioid treatment of chronic nonmalignant pain were present.

Do implantable devices improve mood? Comparisons of chronic pain patients with or without an implantable device

Objective.  This descriptive study compares outcome measures of a computerized assessment of pain, emotional distress, and quality of life between chronic noncancer pain patients who have received an implantable device (spinal cord stimulator or intrathecal pump; N = 143) and those who have not received a device (N = 130). Methods.  Each patient marked the location of their pain on a body diagram and rated pain intensity, emotional distress, and impact of their pain on mood, sleep, and quality of life using a computerized pain assessment program. An electronic version of the Hospital Anxiety and Depression Scale (HADS) also was administered. Results.  No significant differences were found on the pain variables between the two groups. Patients with an implantable device gave lower ratings (less impact) on emotional distress (p < 0.05) and rated their health quality of life as better compared with control patients (p < 0.05). The patients with implantable devices also scored lower on the HADS Depression Subscale. Conclusion.  The results suggest that although patients with an implantable device seem to have more pathology and greater disability, they report less emotional distress and improved quality of life compared with patients with chronic pain without an implantable device. Future controlled trials are needed to establish the role that an implantable device plays in improving mood and quality of life.

A Prospective, Randomized Trial of Intrathecal Injection vs. Epidural Infusion in the Selection of Patients for Continuous Intrathecal Opioid Therapy

The objective of this study was to compare the cost and safety of intrathecal injection (IN) vs. epidural infusion (CE) trial and to provide a preliminary assessment of the prognostic value of each in the selection of patients for long-term continuous intrathecal opioid therapy (CIOT). Thirty-seven patients with chronic nonmalignant pain who were being considered for CIOT were randomized to morphine trial by IN or CE. Analgesic response and complications were monitored throughout trial. Sixty-seven percent of IN (12/18) and 79% (15/19) of CE subjects reported good pain relief (defined as ≥ 50% pain reduction) and were implanted with a permanent infusion system. Eighty-nine percent (24/27) of subjects provided six-month CIOT follow-up data. Cost of trial and health care utilization during six months of CIOT were compared between groups. Analgesic and functional response during CIOT was also compared between IN and CE groups. The cost of IN trial was significantly less than CE trial (p < 0.001). Complications were generally mild in both groups, although opioid-related side effects tended to be more common in the IN group. Successful pain relief after six months of CIOT was reported by 10 (60%) and 14 (64%) patients who underwent IN and CE trial, respectively (p = 0.32; Fisher's exact test). There was no difference between IN and CE groups in McGill Pain rating, quality of life (VAS), mood (Profile of Mood States), or function (Sickness Impact Profile) after six months of CIOT. We conclude that intrathecal injection is a safe procedure for use in selection of patients for CIOT and is less costly than epidural infusion. Differences in pain and functional response to long-term opioids among patients selected by either trial method are not large.

Guidance on the management of pain in older people

This guidance document reviews the epidemiology and management of pain in older people via a literature review of published research. The aim of this document is to inform health professionals in any care setting who work with older adults on best practice for the management of pain and to identify where there are gaps in the evidence that require further research. The assessment of pain in older people has not been covered within this guidance and can be found in a separate document (http://www.britishpainsociety.org/pub_professional.htm#assessmentpop). Substantial differences in the population, methods and definitions used in published research makes it difficult to compare across studies and impossible to determine the definitive prevalence of pain in older people. There are inconsistencies within the literature as to whether or not pain increases or decreases in this age group, and whether this is influenced by gender. There is, however, some evidence that the prevalence of pain is higher within residential care settings. The three most common sites of pain in older people are the back; leg/knee or hip and 'other' joints. In common with the working-age population, the attitudes and beliefs of older people influence all aspects of their pain experience. Stoicism is particularly evident within this cohort of people. Evidence from the literature search suggests that paracetamol should be considered as first-line treatment for the management of both acute and persistent pain, particularly that which is of musculoskeletal origin, due to its demonstrated efficacy and good safety profile. There are few absolute contraindications and relative cautions to prescribing paracetamol. It is, however, important that the maximum daily dose (4 g/24 h) is not exceeded. Non-selective non-steroidal anti-inflammatory drugs (NSAIDs) should be used with caution in older people after other safer treatments have not provided sufficient pain relief. The lowest dose should be provided, for the shortest duration. For older adults, an NSAID or cyclooxygenase-2 (COX-2) selective inhibitor should be co-prescribed with a proton pump inhibitor (PPI), and the one with the lowest acquisition cost should be chosen. All older people taking NSAIDs should be routinely monitored for gastrointestinal, renal and cardiovascular side effects, and drug–drug and drug–disease interactions. Opioid therapy may be considered for patients with moderate or severe pain, particularly if the pain is causing functional impairment or is reducing their quality of life. However, this must be individualised and carefully monitored. Opioid side effects including nausea and vomiting should be anticipated and suitable prophylaxis considered. Appropriate laxative therapy, such as the combination of a stool softener and a stimulant laxative, should be prescribed throughout treatment for all older people who are prescribed opioid therapy. Tricyclic antidepressants and anti-epileptic drugs have demonstrated efficacy in several types of neuropathic pain. But, tolerability and adverse effects limit their use in an older population. Intra-articular corticosteroid injections in osteoarthritis of the knee are effective in relieving pain in the short term, with little risk of complications and/or joint damage. Intra-articular hyaluronic acid is effective and free of systemic adverse effects. It should be considered in patients who are intolerant to systemic therapy. Intra-articular hyaluronic acid appears to have a slower onset of action than intra-articular steroids, but the effects seem to last longer. The current evidence for the use of epidural steroid injections in the management of sciatica is conflicting and, until further larger studies become available, no firm recommendations can be made. There is, however, a limited body of evidence to support the use of epidural injections in spinal stenosis. The literature review suggests that assistive devices are widely used and that the ownership of devices increases with age. Such devices enable older people with chronic pain to live in the community. However, they do not necessarily reduce pain and can increase pain if used incorrectly. Increasing activity by way of exercise should be considered. This should involve strengthening, flexibility, endurance and balance, along with a programme of education. Patient preference should be given serious consideration. A number of complementary therapies have been found to have some efficacy among the older population, including acupuncture, transcutaneous electrical nerve stimulation (TENS) and massage. Such approaches can affect pain and anxiety and are worth further investigation. Some psychological approaches have been found to be useful for the older population, including guided imagery, biofeedback training and relaxation. There is also some evidence supporting the use of cognitive behavioural therapy (CBT) among nursing home populations, but of course these approaches require training and time. There are many areas that require further research, including pharmacological management where approaches are often tested in younger populations and then translated across. Prevalence studies need consistency in terms of age, diagnosis and terminology, and further work needs to be done on evaluating non-pharmacological approaches.

Continuous intrathecal morphine administration for cancer pain management using an intrathecal catheter connected to a subcutaneous injection port: a retrospective analysis of 22 terminal cancer patients in korean population

Background

Intrathecal opioid administration has been used widely in patients suffering from severe cancer pain that is not managed with conventional modalities. However, the potential serious neurological complications from the procedure and the side effects of intrathecal opioids have made many clinicians reluctant to employ continuous intrathecal analgesia as a first-line therapeutic option despite its dramatic effect on intractable pain. We retrospectively investigated the efficacy, side effects, and complications of intrathecal morphine administration through intrathecal catheters connected to a subcutaneous injection port (ICSP) in 22 Korean terminal cancer patients with successful intrathecal morphine trials.

Methods

Patient demographic data, the duration of intrathecal opioid administration, preoperative numerical pain rating scales (NRS) and doses of systemic opioids, side effects and complications related to intrathecal opioids and the procedure, and the numerical pain rating scales and doses of intrathecal and systemic opioids on the 1^st, 3^rd, 7^th and 30^th postoperative days were determined from medical records.

Results

Intrathecal morphine administration for 46.0 ± 61.3 days significantly reduced NRS from baseline on all the postoperative days. A significant increase in intrathecal opioids with a nonsignificant decrease in systemic opioids was observed on the 7^th and 30^th postoperative days compared to the 1^st postoperative day. The most common side effects of intrathecal opioids were nausea/vomiting (31.8%) and urinary retention (38.9%), which were managed with conservative therapies.

Conclusions

Intrathecal morphine administration using ICSP provided immediate and beneficial effects on pain scores with tolerable side effects in terminal cancer patients.

Effective management of intractable neuropathic pain using an intrathecal morphine pump in a patient with acute transverse myelitis

Transverse myelitis is a rare inflammatory myelopathy characterized by loss of motor and sensory function below the affected level of the spinal cord, and causes neurogenic bowel and bladder. Occasionally, it also causes neuropathic pain with spasticity. Traditional therapies for neuropathic pain are multiple, including multimodal analgesic regimens, antiepileptic or antidepressant medications, opioids, sympathetic blocks, and spinal cord stimulation. Persistent neuropathic pain can cause emotional distress by affecting sleep, work, recreation, and emotional well-being. Here we report the case of a patient suffering from intractable neuropathic pain following acute transverse myelitis that was not relieved by combinations of nonsteroidal anti-inflammatory, anti-epileptic, antidepressant, and opioid medications, or by acupuncture. Implantation of an intrathecal morphine pump controlled the pain successfully without side effects, and enabled the patient to embark on intensive rehabilitation. The patient's muscle strength has improved significantly and the patient may soon be able to use a walker with minimal assistance.

Compact, power-efficient architectures using microvalves and microsensors, for intrathecal, insulin, and other drug delivery systems

This paper describes a valve-regulated architecture, for intrathecal, insulin and other drug delivery systems, that offers high performance and volume efficiency through the use of micromachined components. Multi-drug protocols can be accommodated by using a valve manifold to modulate and mix drug flows from individual reservoirs. A piezoelectrically-actuated silicon microvalve with embedded pressure sensors is used to regulate dosing by throttling flow from a mechanically-pressurized reservoir. A preliminary prototype system is demonstrated with two reservoirs, pressure sensors, and a control circuit board within a 130cm(3) metal casing. Different control modes of the programmable system have been evaluated to mimic clinical applications. Bolus and continuous flow deliveries have been demonstrated. A wide range of delivery rates can be achieved by adjusting the parameters of the manifold valves or reservoir springs. The capability to compensate for changes in delivery pressure has been experimentally verified. The pressure profiles can also be used to detect catheter occlusions and disconnects. The benefits of this architecture compared with alternative options are reviewed.

Intrathecal drug delivery system (IDDS) for cancer pain management: a review and updates

Cancer pain remains undertreated and a significant number of patients with cancer pain die from severe untreated pain. With increasing survival rate in cancer, the prevalence of cancer pain is also increasing in number. Though majority of patients with cancer pain can be effectively treated with conventional medical management, still a significant portion of patients required some form of interventional pain management techniques. Among the interventional techniques, intrathecal drug delivery is increasingly used in cancer pain management. Our objective of this article is to review literatures and clinical studies on intrathecal drug delivery system (IDDS) in cancer pain management and to provide updates on its use, precautions, contraindications, side effects and its management, socioeconomic consideration, and management of IDDS in difficult or uncommon situations.