Polyanalgesic Consensus Conference--2012: recommendations to reduce morbidity and mortality in intrathecal drug delivery in the treatment of chronic pain

The Polyanalgesic Consensus Conference (PACC)®: Intrathecal Drug Delivery Guidance on Safety and Therapy Optimization When Treating Chronic Noncancer Pain

INTRODUCTION

The International Neuromodulation Society convened a multispecialty group of physicians and scientists based on expertise with international representation to establish evidence-based guidance on intrathecal drug delivery in treating chronic pain. This Polyanalgesic Consensus Conference (PACC)® project, created more than two decades ago, intends to provide evidence-based guidance for important safety and efficacy issues surrounding intrathecal drug delivery and its impact on the practice of neuromodulation.

MATERIALS AND METHODS

Authors were chosen on the basis of their clinical expertise, familiarity with the peer-reviewed literature, research productivity, and contributions to the neuromodulation literature. Section leaders supervised literature searches of MEDLINE, BioMed Central, Current Contents Connect, Embase, International Pharmaceutical Abstracts, Web of Science, Google Scholar, and PubMed from 2017 (when PACC® last published guidelines) to the present. Identified studies were graded using the United States Preventive Services Task Force criteria for evidence and certainty of net benefit. Recommendations are based on the strength of evidence or consensus when evidence is scant.

RESULTS

The PACC® examined the published literature and established evidence- and consensus-based recommendations to guide best practices. Additional guidance will occur as new evidence is developed in future iterations of this process.

CONCLUSIONS

The PACC® recommends best practices regarding intrathecal drug delivery to improve safety and efficacy. The evidence- and consensus-based recommendations should be used as a guide to assist decision-making when clinically appropriate.

Intrathecal drug delivery for the management of pain and spasticity in adults: British Pain Society's recommendations for best clinical practice

The British Pain Society updated their recommendations on intrathecal drug delivery (ITDD) for the management of pain and spasticity in adults. The recommendations are primarily evidence based but where necessary comprise the consensus opinion of the working group. The recommendations are accompanied by information for patients and their carers, intended to inform and support patients in their decision making. The updated guidance includes recent evidence base of ITDD use in pain and spasticity, address the issues of drug pump compatibility following the latest manufacturer and Medicines and Healthcare products Regulatory Agency (MHRA) recommendations as well as provide an update on the indications and complication management particularly endocrine complications and intrathecal granuloma formation.

A Bibliometric Analysis of Top-Cited Journal Articles Related to Neuromodulation for Chronic Pain

OBJECTIVES

Since its foundation in the 1960s, neuromodulation has become an increasingly used treatment option for chronic pain. This bibliometric analysis examines the most cited research in this field with the aim of uncovering existing trends and future directions.

MATERIALS AND METHODS

Clarivate's Web of Science data base was searched for the top 25 most cited studies focusing on neuromodulation for chronic pain. Various bibliometric parameters were then extracted and analyzed. Randomized controlled trials (RCTs) were compared with non-RCTs.

RESULTS

The top 25 articles had a mean of 347 citations and 22.2 citations per year, with more recent articles having a higher citation rate. Most were published in the last two decades and predominantly originated from the United States. There were 13 RCTs, which were significantly more recent (p = 0.004) and more cited per year (p = 0.001) than the 12 non-RCTs. Sources included 15 journals with a mean impact factor of 13.896. The most studied modality was spinal cord stimulation with 20 articles (76.9%), followed by intrathecal drug delivery (15.4%), dorsal root ganglion stimulation (3.8%), and peripheral nerve stimulation (3.8%).

CONCLUSIONS

Analysis of the most cited articles on neuromodulation reveals a focal shift from historical reports to innovative RCTs that have increasingly guided pain practice in the recent years. As novel techniques and technologies continue to develop, high-quality evidence coupled with broadening indications will likely direct further expansion of this field.

Stability of Morphine Sulfate-Clonidine and Sufentanil-Clonidine Mixtures

BACKGROUND

Spinal analgesia is recommended for intractable cancer pain. Morphine-clonidine and sufentanil-clonidine are often used in association in intrathecal drug delivery systems, injected by intraabdominal pumps. To refill these pumps and to limit patient transport, it may be necessary to ship the mixtures in polypropylene syringes to peripheral establishments located near patient homes. The purpose of this study is to determine the stability of morphine-clonidine and sufentanil-clonidine mixtures in polypropylene syringes to ensure the best and safest transport conditions and in implantable pumps for intrathecal use.

MATERIALS AND METHODS

The stability study method was conceived according to the International Council for Harmonization guidelines. For polypropylene syringes, four different mixtures of morphine-clonidine and sufentanil-clonidine were assessed over seven days. Two storage temperatures were tested (5 ± 3 °C and 25 ± 2 °C). For implantable pumps, two different mixtures of morphine-clonidine and sufentanil-clonidine were assessed over 28 days and stored at 37 °C.

RESULTS

For the morphine-clonidine mixtures in polypropylene syringes, all mixtures remained stable for five days in both storage conditions (5 ± 3 °C and 25 ± 2 °C) because of relative concentrations systematically positioned between 90% and 110% (95% CIs of the mean of three samples). The two mixtures in implantable pumps remained stable for 28 days. For the sufentanil-clonidine mixtures in polypropylene syringes, cold conservation kept all the preparations stable for seven days, whereas a quick degradation was observed after only two days for ambient storage conditions. This result is similar to that with an implantable pump, in which the concentration is <90% on day 7 for low concentration mixtures. No visual modification, no significant pH modification, and no changes in turbidity assays were observed in either study.

CONCLUSION

This study shows the stability of the morphine-clonidine mixtures in syringes stored at 5 °C for five days and in implantable pumps stored at 37 °C for 28 days. For the sufentanil-clonidine mixtures, the results show stability in syringes for seven days at 5 °C. Pump results show stability of seven days for low concentrations and 28 days for high concentrations.

First Evaluation Switching From Ropivacaine to Highly Concentrated Bupivacaine in Intrathecal Mixtures for Cancer Pain

BACKGROUND

Intrathecal drug delivery is widely used for intractable cancer pain treatment. A combination of drugs with morphine and bupivacaine is recommended in first line therapy. In France, we use ropivacaine 10 mg/mL instead of bupivacaine 5 mg/mL, the only concentration available. Bupivacaine 40 mg/mL has been available in France only since July 2020 under temporary authorization of use.

OBJECTIVES

The main objective of the study was to evaluate the safety, efficacy by pain assessment, to analyze drug dosage changes, to report adverse events (AEs) and conversion ratios switching from ropivacaine to bupivacaine. Secondary objective was to evaluate costs differences.

MATERIALS AND METHODS

We conducted this retrospective follow-up monocentric study within the Institut de Cancérologie de l'Ouest (ICO) Pain Department in Angers, France. We included 14 patients aged 18 years and above, implanted with an Intrathecal Drug Delivery Systems (IDDS) for cancer pain treatment and followed up at ICO from July 2020 to February 2021 after switching from ropivacaine to bupivacaine. We used a continuous infusion mode and Bolus could be added through Personal Therapy Manager (PTM).

RESULTS

The median conversion ratio between ropivacaine and bupivacaine was 0.68 (0.65; 0.69) and resulted in no significant change in numeric rating scale evaluation (p = 0.10). We observed moderate and rapidly reversible AEs such as clinical hypotension (29%) and motor block after bolus (21%). The estimated median hospital cost per day was significantly lower (p = 0.05) for the bupivacaine refills than for the last ropivacaine pump refill, decreasing from US$ 61.7 (49.6; 70.5) to US$ 50.4 (45.9; 60.4). The median reimbursement per day from the National Health Insurance (NHI) was three times lower for bupivacaine pump refill when compared to the last ropivacaine pump refill (p < 0.01), decreasing from US$ 179.10 (156.79; 182.91) to US$ 64.59 (59.85; 71.89).

CONCLUSION

Switching from ropivacaine to bupivacaine in IDDS appears more efficacious while remaining just as secure, and at lower cost.

A Comprehensive Update of the Superior Hypogastric Block for the Management of Chronic Pelvic Pain

PURPOSE OF REVIEW

This is a comprehensive review of the superior hypogastric block for the management of chronic pelvic pain. It reviews the background, including etiology, epidemiology, and current treatment available for chronic pelvic pain. It then presents the superior hypogastric block and reviews the seminal and most recent evidence about its use in chronic pelvic pain.

RECENT FINDINGS

Several definitions exist for chronic pelvic pain (CPP), making the diagnosis more challenging for the clinician; however, they commonly describe continuous pain lasting 6 months in the pelvis, with an overwhelming majority of patients being reproductive-aged women. This pain is often one of mechanical, inflammatory, or neuropathic. It is generally underdiagnosed and affects anywhere between 5 and 26% of women. The diagnosis of chronic pelvic pain is clinical, consisting of mainly of a thorough history and physical and ruling out other causes. The pathophysiology is often endometriosis (70%) and also includes PID, adhesions, adenomyosis, uterine fibroids, chronic processes of the GI and urinary tracts, as well as pelvic-intrinsic musculoskeletal causes. Treatment includes physical therapy, cognitive behavioral therapy, and oral and parenteral opioids. Interventional techniques provide an added tier of treatment and may help to reduce the requirement for chronic opioid use. Superior hypogastric plexus block is one of the available interventional techniques; first described in 1990, it has been shown to provide long-lasting relief in 50-70% of patients who underwent the procedure. Two approaches described so far, both under fluoroscopy, have seen similar results. More recently, ultrasound and CT-guided procedures have also been described with similar success. The injectate includes local anesthetic, steroids, and neurolytic agents such as phenol or ethanol. CPP is a common debilitating condition. It is diagnosed clinically and is underdiagnosed globally. Current treatments can be helpful at times but may fall short of satisfactory pain relief. Interventional techniques provide an added layer of treatment as well as reduce the requirement for opioids. Superior hypogastric plexus block provides long-lasting relief in many patients, regardless of approach. Evidence level is limited, and further RCTs could help provide better tools for evaluation and patient selection.

Role of neuraxial drug delivery in cancer pain therapy

Opioids have long been the mainstay of cancer pain treatment and have been used without any consideration for their effect on cancer growth and long-term prognosis. There is now growing evidence that the continued use of opioids for this indication should be reviewed and even reconsidered. Although current evidence and literature covering this subject is mixed and does not yet allow for a clear determination to be made about safety, there is enough data to support the search for new treatment paradigms, beginning with anesthesia for oncologic surgery and management of cancer pain over the disease course.

Spinal cord injury pain

Spinal cord injury pain encompasses musculoskeletal and neuropathic pain. Its management is often multidisciplinary and involves specific drugs such as antidepressants and antiepileptics, and nonpharmacological treatment including psychotherapy, physical therapy and neuromodulation techniques. Recent progress in the diagnosis, assessment, and understanding of its mechanisms offers the perspective of a more rational therapeutic management, which should result in better therapeutic outcome.

Intrathecal Drug Delivery Systems for Cancer Pain: An Analysis of a Prospective, Multicenter Product Surveillance Registry

BACKGROUND

The safety and efficacy of intrathecal drug delivery systems (IDDSs) for the treatment of cancer-related pain have been demonstrated in randomized controlled clinical trials (RCTs). Despite positive evidence for this therapy, IDDS remains underutilized to treat cancer pain. Real-world registry data augment existing safety and effectiveness data and are presented here to broaden awareness of this therapeutic option, needed for adequate cancer-related pain treatment, and as a viable tool addressing concerns with systemic opioid use.

METHODS

This prospective, long-term, multicenter (United States, Western Europe, and Latin America) registry started in 2003 to monitor the performance of SynchroMed Infusion Systems. Patient-reported outcomes were added in 2013. Before data acquisition, all sites obtained Ethics Committee/Institutional Review Board approval and written patient consent. The study was registered (NCT01524276 at clinicaltrials.gov) before patients were enrolled. Patients who provided informed consent were enrolled in the registry at initial IDDS implant or replacement.

RESULTS

Through July 2017, 1403 patients with cancer pain were enrolled and implanted. The average (minimum/maximum) age of patients was 59 years (13/93 years), with 56.6% female. The most frequent cancer types were lung, breast, colon/rectal, pancreatic, and prostate. The majority of patients whose registry follow-up ended (87%; 1141/1311) were followed through death, with 4.3% (n = 57) exiting due to device explant or therapy discontinuation; the remaining 113 (8.6%) discontinued for reasons such as transfer of care, lost to follow-up, and site closure. Pain scores within the cohort of patients providing baseline and follow-up data improved significantly at 6 (P = .0007; n = 103) and 12 (P = .0026; n = 55) months compared to baseline, with EuroQol with 5 dimensions (EuroQol-5D) scores showing significant improvement at 6 months (P = .0016; n = 41). Infection requiring surgical intervention (IDDS explant, replacement, pocket revision, irrigation and debridement, etc) was reported in 3.2% of patients.

CONCLUSIONS

Adequate and improved pain control in patients with cancer, even in advanced stages, with concurrent quality of life maintenance is attainable. Results from this large-scale, multicenter, single-group cohort supplement existing RCT data that support IDDS as a safe and effective therapeutic option with a positive benefit-risk ratio in the treatment of cancer pain.

Stability study of hydromorphone and bupivacaine mixture by HPLC-UV

Objectives

The objective of this study was to evaluate the physical and chemical stability of hydromorphone hydrochloride and bupivacaine hydrochloride in concentrations of 15 mg.ml^-1 and 10 mg.mL^-1 in 0.9% sodium chloride injection. Test samples of hydromorphone/bupivacaine mixtures were stored at 37°C, body temperature encounterd during continuous intrathecal infusion, for 90 days. The solutions were packaged in 20 ml plastic syringes. Evaluations for physical and chemical stability were performed initially and throughout the storage periods. Physical stability was assessed by visual observation. The chemical stability of the drug was evaluated by means of a stability-indicating high-performance liquid chromatographic (HPLC) analytical technique. In addition, pH and osmolarity were measured electronically.

Methods

This study determines the stability and compatibility of hydromorphone (15 mg.ml^-1) and bupivacaine (10 mg.ml^-1) mixture after 3 months at 37°C using a validated method by HPLC-UV. A simple, precise, specific and accurate reversed phase high performance liquid chromatographic (RP-HPLC) method was developed and validated. The different analytical performance parameters such as linearity, accuracy, specificity, precision and sensitivity (limit of detection and limit of quantitation) were determined according to International Conference on Harmonisation ICH Q2 (R1) guidelines. RP-HPLC was conducted on a nucleoshell RP18plus (C18 150×4.6 mm with 2.7 µm particle size) column. The mobile phase consisted of buffer A (phosphate buffer (0.05M) pH 4.5) and acetonitrile B. The gradient used for the elution is the following one: time (min)/% of B: 0 min/20%; 1.9 min/50%; 2.5 min /40%; 4.5 min/40%; 5.5 min/20%; and 8 min /20%, and the flow rate was maintained at 1.0ml.min^-1 and performed at 35°C. The molecules were monitored using Dionex ultimate 3000, equipped with photo diode array detector (λ=210 nm). Linearity was observed in concentration range of 9-21 mg.l^-1 for hydromorphone and 6-14 mg.l^-1 for bupivacaine. All the system suitability parameters were found within the range.

Results

The degradation study shows a photolytic degradation compound for hydromorphone and an oxidative degradation compound found for bupivacaine. The stability study shows no visible haze or particulate formation or gas evolution. pH and osmolarity were stable during the 3 months. Colour changed after 2 months, although this colouring is due to hydromorphone, proportional to hydromorphone concentrations and increases with time but it is a well known modification. The quantitative study by HPLC method revealed no significant change in hydromorphone and bupivacaine concentration. There is less than 5% of variability during the 3-month period.

Conclusions

Hydromorphone (15 mg.ml^-1) and bupivacaine (10 mg.ml^-1) were physically and chemically compatible and analysed with HPLC, which revealed no significant change in hydromorphone and bupivacaine concentration in this simulated compatibility study.

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.

The Neuromodulation Appropriateness Consensus Committee on Best Practices for Dorsal Root Ganglion Stimulation

INTRODUCTION

The Neuromodulation Appropriateness Consensus Committee (NACC) is dedicated to improving the safety and efficacy of neuromodulation and thus improving the lives of patients undergoing neuromodulation therapies. With continued innovations in neuromodulation comes the need for evolving reviews of best practices. Dorsal root ganglion (DRG) stimulation has significantly improved the treatment of complex regional pain syndrome (CRPS), among other conditions. Through funding and organizational leadership by the International Neuromodulation Society (INS), the NACC reconvened to develop the best practices consensus document for the selection, implantation and use of DRG stimulation for the treatment of chronic pain syndromes.

METHODS

The NACC performed a comprehensive literature search of articles about DRG published from 1995 through June, 2017. A total of 2538 article abstracts were then reviewed, and selected articles graded for strength of evidence based on scoring criteria established by the US Preventive Services Task Force. Graded evidence was considered along with clinical experience to create the best practices consensus and recommendations.

RESULTS

The NACC achieved consensus based on peer-reviewed literature and experience to create consensus points to improve patient selection, guide surgical methods, improve post-operative care, and make recommendations for management of patients treated with DRG stimulation.

CONCLUSION

The NACC recommendations are intended to improve patient care in the use of this evolving therapy for chronic pain. Clinicians who choose to follow these recommendations may improve outcomes.

Refill Procedures of Intrathecal Drug Delivery Systems With a Recessed Fill Port on the Pump Surface: A Prospective Comparison Study of Ultrasound-Guided vs. Blind Refill Technique

OBJECTIVES

Structural differences of implantable drug delivery systems (IDDSs) might have an impact on the efficiency of needle access to the reservoir fill port (RFP). The aim of this study was to assess the efficiency of RFP needle access with an ultrasound (US)-guided vs. a blind refill technique in IDDSs with a Recessed RFP (Recessed-RFP-IDDS).

MATERIALS AND METHODS

The primary outcome was the number of attempts needed to enter the RFP with a needle comparing the US-guided technique vs. the blind refill technique. The time to enter the RFP with the needle was a secondary outcome. We compared the amount of attempts between both techniques with the non-parametric Wilcoxon rank sum test.

RESULTS

Fourteen adult patients underwent a total of 75 refills of their Recessed-RFP-IDDS during a period of 24 months. The median number of attempts to enter the RFP did not differ significantly between the US-guided technique and the blind refill technique (2.0 (IQR: 1-5) vs. 1.5 (IQR: 1-5.0), p = 0.572). The median time to enter the RFP with the needle did not differ significantly between both techniques (35.0 sec (IQR: 26.0-58.0) vs. 41.0 sec (IQR: 25.5-46.8), p = 0.878).

CONCLUSION

The results of this study suggest that there is no difference in the RFP needle access efficiency between the US-guided and the blind refill technique in superficially located Recessed-RFP-IDDSs, if performed by experienced practitioners. However, the study did not address efficiency of the RFP needle access in IDDSs with aberrancy in pump location or refills performed by inexperienced staff.

Effects of opioid and nonopioid analgesics on canine wheal formation and cultured human mast cell degranulation

Mast cell (MC) degranulation has been implicated in the side effect profile of a variety of clinically useful agents. Thus, after intrathecal delivery, formation of space-occupying, meningeally-derived masses may be related to local MC degranulation. We systematically characterized degranulating effects of opioid and nonopioid analgesics on cutaneous flares in the dog and in primary human MC (hMC) cultures.

METHODS

Dogs were anesthetized with IV propofol and received intradermal (ID) injections (50μL). Flare diameters were measured at 30min. Drugs showing flare responses were tested after intramuscular (IM) cromolyn (10mg/kg), a MC stabilizer. Human primary MCs (human cord blood CD34⁺/CD45⁺ cells) were employed and β-hexosaminidase in cell-free supernatants were measured to assess degranulation.

RESULTS

A significant skin flare for several classes of agents was observed including opioids, ziconotide, ketamine, ST-91, neostigmine, adenosine, bupivacaine, lidocaine, MK-801 and 48/80. Tizanidine, fentanyl, alfentanil, gabapentin and baclofen produced no flare. Flare produced by all ID agents, except adenosine, bupivacaine and lidocaine, was reduced by cromolyn. Naloxone had no effect upon opiate or 48/80 evoked flares. In hMC studies, 48/80 resulted in a concentration-dependent release of β-hexosaminidase. The rank order of drug-induced hMC β-hexosaminidase release was similar to that for flares.

CONCLUSIONS

A variety of therapeutically useful drugs degranulate MCs. This action may account for side effects such as the intrathecal granuloma resulting from spinally-delivered opioids. This degranulating effect may be useful in predicting potential intrathecal toxicity in the development of novel agents.

Computational and In Vitro Experimental Investigation of Intrathecal Drug Distribution: Parametric Study of the Effect of Injection Volume, Cerebrospinal Fluid Pulsatility, and Drug Uptake

BACKGROUND

Intrathecal drug delivery is an attractive option to circumvent the blood-brain barrier for pain management through its increased efficacy of pain relief, reduction in adverse side effects, and cost-effectiveness. Unfortunately, there are limited guidelines for physicians to choose infusion or drug pump settings to administer therapeutic doses to specific regions of the spine or the brain. Although empiric trialing of intrathecal drugs is critical to determine the sustained side effects, currently there is no inexpensive in vitro method to guide the selection of spinal drug delivery parameters. The goal of this study is to demonstrate current computational capabilities to predict drug biodistribution while varying 3 parameters: (1) infusion settings, (2) drug chemistry, and (3) subject-specific anatomy and cerebrospinal fluid dynamics. We will discuss strategies to systematically optimize these 3 parameters to administer drug molecules to targeted tissue locations in the central nervous system.

METHODS

We acquired anatomical data from magnetic resonance imaging (MRI) and velocity measurements in the spinal cerebrospinal fluid with CINE-MRI for 2 subjects. A bench-top surrogate of the subject-specific central nervous system was constructed to match measured anatomical dimensions and volumes. We generated a computational mesh for the bench-top model. Idealized simulations of tracer distribution were compared with bench-top measurements for validation. Using reconstructions from MRI data, we also introduced a subject-specific computer model for predicting drug spread for the human volunteer.

RESULTS

MRI velocity measurements at 3 spinal regions of interest reasonably matched the simulated flow fields in a subject-specific computer mesh. Comparison between the idealized spine computations and bench-top tracer distribution experiments demonstrate agreement of our drug transport predictions to this physical model. Simulated multibolus drug infusion theoretically localizes drug to the cervical and thoracic region. Continuous drug pump and single bolus injection were successful to target the lumbar spine in the simulations. The parenchyma might be targeted suitably by multiple boluses followed by a flush infusion. We present potential guidelines that take into account drug specific kinetics for tissue uptake, which influence the speed of drug dispersion in the model and potentially influence tissue targeting.

CONCLUSIONS

We present potential guidelines considering drug-specific kinetics of tissue uptake, which determine the speed of drug dispersion and influence tissue targeting. However, there are limitations to this analysis in that the parameters were obtained from an idealized healthy patient in a supine position. The proposed methodology could assist physicians to select clinical infusion parameters for their patients and provide guidance to optimize treatment algorithms. In silico optimization of intrathecal drug delivery therapies presents the first steps toward a possible care paradigm in the future that is specific to personalized patient anatomy and diseases.

Injury and Liability Associated with Implantable Devices for Chronic Pain

BACKGROUND

Due to an increase in implantable device-related anesthesia pain medicine claims, the authors investigated anesthesia liability associated with these devices.

METHODS

After institutional review board approval, the authors identified 148 pain medicine device claims from 1990 or later in the Anesthesia Closed Claims Project Database. Device-related damaging events included medication administration events, infections, hematomas, retained catheter fragments, cerebrospinal fluid leaks, cord or cauda equina trauma, device placed at wrong level, stimulator incorrectly programmed, delay in recognition of granuloma formation, and other issues.

RESULTS

The most common devices were implantable drug delivery systems (IDDS; 64%) and spinal cord stimulators (29%). Device-related care consisted of surgical device procedures (n = 107) and IDDS maintenance (n = 41). Severity of injury was greater in IDDS maintenance claims (56% death or severe permanent injury) than in surgical device procedures (26%, P < 0.001). Death and brain damage in IDDS maintenance claims resulted from medication administration errors (n = 13; 32%); spinal cord injury resulted from delayed recognition of granuloma formation (n = 9; 22%). The most common damaging events for surgical device procedures were infections, inadequate pain relief, cord trauma, retained catheter fragments, and subcutaneous hygroma. Care was more commonly assessed as less than appropriate (78%) and payments more common (63%) in IDDS maintenance than in surgical device procedure claims (P < 0.001).

CONCLUSIONS

Half of IDDS maintenance claims were associated with death or permanent severe injury, most commonly from medication errors or failure to recognize progressive neurologic deterioration. Practitioners implanting or managing devices for chronic pain should exercise caution in these areas to minimize patient harm.

Neuropathic pain

Neuropathic pain is caused by a lesion or disease of the somatosensory system, including peripheral fibres (Aβ, Aδ and C fibres) and central neurons, and affects 7-10% of the general population. Multiple causes of neuropathic pain have been described and its incidence is likely to increase owing to the ageing global population, increased incidence of diabetes mellitus and improved survival from cancer after chemotherapy. Indeed, imbalances between excitatory and inhibitory somatosensory signalling, alterations in ion channels and variability in the way that pain messages are modulated in the central nervous system all have been implicated in neuropathic pain. The burden of chronic neuropathic pain seems to be related to the complexity of neuropathic symptoms, poor outcomes and difficult treatment decisions. Importantly, quality of life is impaired in patients with neuropathic pain owing to increased drug prescriptions and visits to health care providers, as well as the morbidity from the pain itself and the inciting disease. Despite challenges, progress in the understanding of the pathophysiology of neuropathic pain is spurring the development of new diagnostic procedures and personalized interventions, which emphasize the need for a multidisciplinary approach to the management of neuropathic pain.

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.

Palliative care and pediatric surgical oncology

Survival rate for childhood cancer has increased in recent years, reaching as high as 70% in developed countries compared with 54% for all cancers diagnosed in the 1980s. In the remaining 30%, progression or metastatic disease leads to death and in this framework palliative care has an outstanding role though not well settled in all its facets. In this landscape, surgery has a supportive actor role integrated with other welfare aspects from which are not severable. The definition of surgical palliation has moved from the ancient definition of noncurative surgery to a group of practices performed not to cure but to alleviate an organ dysfunction offering the best quality of life possible in all the aspects of life (pain, dysfunctions, caregivers, psychosocial, etc.). To emphasize this aspect a more modern definition has been introduced: palliative therapy in whose context is comprised not only the care assistance but also the plans of care since the onset of illness, teaching the matter to surgeons in training and share paths. Literature is very poor regarding surgical aspects specifically dedicated and all researches (PubMed, Google Scholar, and Cochrane) with various meshing terms result in a more oncologic and psychosocial effort.

Primary Hydromorphone-Related Intrathecal Catheter Tip Granulomas: Is There a Role for Dose and Concentration?

BACKGROUND

Intrathecal drug delivery therapy has been used effectively in treating patients with intractable chronic pain. The development of an intrathecal catheter tip granuloma (ICTG) related to delivery of intrathecal opiates is a relatively infrequent, but potentially devastating complication. While there are many morphine-related ICTG cases described, reports of hydromorphone-related ICTG are limited. In addition, studies suggest a strong correlation between the use of higher doses and concentrations of intrathecal opiates and ICTG formation.

OBJECTIVE

The objective of this study is to determine the incidence and the association of intrathecal hydromorphone dose, concentration, duration of treatment and concomitant agents with ICTG formation.

STUDY DESIGN

This is a retrospective analysis of 101 consecutive patients implanted with intrathecal infusion delivery devices. Data were collected from chart review, and records of pump refills from the division of Pain Medicine of University Hospitals or outsourced to a home pump refill service.

RESULTS

From a cohort of 101 consecutively implanted patients, 69 were treated with intrathecal hydromorphone and followed up postimplant for an average of 33.5 ± 24 months (range 0-93 months; 95% CI of 27-39 months). The incidence of ICTG in our patient population was 8.7% during this period of time postimplant with mean time to granuloma detection 35.1 ± 7.9 months. Patients developing granuloma (n = 6) were treated with a combination of intrathecal hydromorphone and bupivacaine infusion. Exposure time to intrathecal agents was not different between the granuloma and nongranuloma group. Monthly dose increase of hydromorphone was higher in granuloma group vs. non-granuloma group (58 ± 34 mcg/month n = 6 vs. 25 ± 8 mcg/month n = 63). Four out of six granuloma cases occurred with low dose and concentration of IT hydromorphone (160-370 mcg/day; 0.75-1.0 mg/mL concentration). Intrathecal bupivacaine dose was not different between groups. A subset of patients was treated with intrathecal fentanyl and bupivacaine. No intrathecal granulomas occurred in this patient cohort.

CONCLUSION

This is the first clinical report demonstrating an association of hydromorphone with intrathecal granulomas, particularly at low doses and concentrations of hydromorphone. This study supports the notion that using low dose of IT opioids might not protect against ICTG development but that the level of exposure and type of opioid used in IT space might be highly correlated with ICTG development. Further research and recommendations related to chronic intrathecal opioid infusions are necessary to raise awareness of significant incidence of ICTG and development of tests to isolate patient populations at high risk.

CE: Intrathecal Pumps for Managing Cancer Pain

: It is estimated that more than 1.6 million new cases of cancer were diagnosed in the United States in 2014. Among patients with cancer, moderate to severe pain is prevalent and can be refractory, even with the use of systemic opioids, which may cause adverse effects that are difficult to manage at the doses required to control pain. When delivered intrathecally, however, opioids and adjuvant analgesics may provide greater pain relief at dramatically lower doses and with fewer adverse effects. Although the use of intrathecal drug delivery systems for cancer pain management has increased dramatically over the past several years and is expected to continue growing, patients with intrathecal pumps often report interactions with nurses unfamiliar with the technology. This article provides an overview of intrathecal pump therapy and explains how it prolongs duration of action and improves the efficacy of certain analgesics while reducing their adverse effects. The author discusses the costs involved, the patients most likely to derive benefit, the types of pumps currently used in the United States, the medications that can be delivered intrathecally, the potential risks and complications associated with intrathecal therapy, and the nursing care required by patients who use an intrathecal pump.

Advances in intrathecal drug delivery

PURPOSE OF REVIEW

Targeted intrathecal drug delivery systems (IDDS) are an option in algorithms for the treatment of patients with moderate-to-severe chronic refractory pain. This article is intended to review the literature regarding IDDS published over the last year, with special attention to the Polyanalgesic Consensus Conference 2012.

RECENT FINDINGS

The recommendations made by the Polyanalgesic Consensus Conference 2012 are reviewed. Separate considerations of intrathecal drug therapy for neuropathic and nociceptive pain syndromes and the new concept of 'microdosing' are discussed in this article.

SUMMARY

This review includes the recommendations for the use of IDDS, trialing, and recent reports of complications (especially, the occurrence of granulomas). In addition, the latest documents on cerebrospinal fluid and potential lines of future development are discussed.

Clinical Uses of Intrathecal Therapy and Its Placement in the Pain Care Algorithm

Intrathecal drug delivery is an effective treatment option for patients with severe chronic pain who have not obtained adequate analgesia from more conservative therapies (eg, physical therapy, systemic opioids, nonsteroidal anti-inflammatory drugs, antidepressants, and anticonvulsants). This review focuses on, but is not limited to, the 2 agents currently approved by the U.S. Food and Drug Administration for intrathecal analgesia: preservative-free morphine and ziconotide (a nonopioid, selective N-type calcium channel blocker). We describe the appropriate use of intrathecal therapy in the management of severe chronic pain, based on current best practices. Topics addressed here include patient selection, trialing, dosing and titration, adverse event profiles, long-term management, intrathecal therapy for cancer-related pain, and the placement of intrathecal therapy in the pain care algorithm. In appropriately selected patients with chronic pain, intrathecal therapy can provide substantial pain relief with improved functioning and quality of life. Successful long-term management requires ongoing patient monitoring for changes in efficacy and the occurrence of adverse events, with subsequent changes in intrathecal dosing and titration, the addition of adjuvant intrathecal agents, and the use of concomitant oral medications to address side effects, as needed. Based on an infrequent but clinically concerning risk of overdose, granuloma, and other opioid-induced complications, nonopioid therapy with ziconotide may be preferred as a first-line intrathecal therapy in patients without a history of psychosis or allergy.

Advanced Innovations for Pain

Chronic pain represents one of the most important public health problems in terms of both the number of patients afflicted and health care costs. Most patients with chronic pain are treated with medications as the mainstay of therapy, and yet most medically treated patients continue to report ongoing pain. Additionally, adverse effects from pain medications represent a major challenge for clinicians and patients. Spinal cord stimulation and intrathecal drug delivery systems are well-established techniques that have been utilized for over 25 years. Intrathecal drug delivery systems have proven efficacy for a wide variety of intractable pain conditions and fewer adverse effects than systemic medical therapy in patients with refractory cancer-related pain. Spinal cord stimulation is cost-effective and provides improved pain control compared with medical therapy in patients with a variety of refractory pain conditions including complex regional pain syndrome, painful diabetic neuropathy, and chronic radiculopathy. Patients who have intractable pain that has not responded to reasonable attempts at conservative pain care measures should be referred to a qualified interventional pain specialist to determine candidacy for the procedures discussed in this article.

An Overview of Pharmacologic Management of Chronic Pain

Patients with chronic pain can be challenging to manage and historically providers have relied on opiates to treat pain. Recent studies have brought into question the safety and efficacy of chronic opiate therapy in the noncancer population. There is a vast amount of literature to support the use of nonsteroidal anti-inflammatory medications, antidepressants, anticonvulsants, topical agents, cannabinoids, and botulinum toxin either in conjunction with or in lieu of opioids. Intrathecal drug delivery systems can deliver some of these medications directly to their primary site of action while minimizing the side effects seen with systemic administration.

Intrathecal Hydromorphone and Bupivacaine Combination Therapy for Post-Laminectomy Syndrome Optimized with Patient-Activated Bolus Device

BACKGROUND

Intrathecal (IT) pumps have become a valuable tool in managing intractable non-cancer pain. The purpose of this study was to evaluate the efficacy of using a rigorous treatment algorithm for trialing and implanting IT pumps with hydromorphone and bupivacaine in managing a more homogeneous population of post-laminectomy syndrome or failed back surgery syndrome (FBSS) patients.

METHODS

This is a retrospective analysis of FBSS patients with chronic intractable back pain implanted with IT pumps delivering hydromorphone and bupivacaine.

RESULTS

A cohort of 57 (26 males, 31 females) consecutively implanted FBSS patients was analyzed. The average age at implant was 65.4 years. Average pain scores were 8.4 ± 0.2 (pre-implant), 4.9 ± 0.4 (6 months), 5.2 ± 0.5 (12 months), and 4.3 ± 0.5 (24 months). Average oral opioid doses in morphine equivalents were 56 ± 10 mg/day (pre-implant), 12.0 ± 3.5 mg/day (12 months), 15 ± 6 mg/day (24 months). Average IT hydromorphone doses were 79 ± 6.8 mcg/day (at implant), 184 ± 22 mcg/day (6 months), 329 ± 48 mcg/day (12 months), and 487 ± 80 mcg (24 months). IT hydromorphone dose escalation from baseline was 133% (6 months vs baseline), 78% (12 months vs 6 months), and 48% from 12 months to 24 months. Average IT bupivacaine doses were 5.8 ± 0.3 mg/day (implant), 9.5 ± 0.6 mg/day (6 months), 12.2 ± 0.7 mg/day (12 months), and 12.6 ± 0.9 mg/day (24 months).

CONCLUSION

IT hydromorphone and bupivacaine are effective in treating chronic pain of FBSS, as demonstrated by the reduction of pain intensity and oral opioid consumption. However, an IT dose escalation phenomenon was observed, although at a reduced rate compared with what had been previously reported in the literature. It is possible that the local anesthetic combination delivered via a patient-activaed bolus device is an important factor. Despite demonstrating effectiveness, the clinical utility of myPTM-optimized IT therapy remains limited by a lack of prospective, placebo-controlled trials and comparative effectiveness research.

Intrathecal drug delivery for the management of pain and spasticity in adults: an executive summary of the British Pain Society's recommendations for best clinical practice

This article provides a summary of the updated British Pain Society Guidance on Intrathecal Drug Delivery for the management of pain and spasticity in adults. We aim to highlight the areas of the guidance that have been updated and to provide a concise summary.

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.

Interventional modalities to treat cancer-related pain

Cancer-related pain is a significant cause of morbidity in those affected by both primary and metastatic disease. Although oral, transdermal, and parenteral opioid medications are an integral part of the World Health Organization's analgesic ladder, their use may be limited by side effects. Fortunately, there are advanced interventional pain management strategies effective in reducing pain in the cancer patient while mitigating the aforementioned side effects. Celiac plexus blocks and neurolysis have been proven effective in treating cancers of the abdominal viscera (ie, pancreas). Transversus abdominis plane blocks, neurolysis, and catheter placement can be used to treat cancer pain associated with the abdominal wall. Peripheral nerve blocks and catheter placement at the brachial and lumbosacral plexus or peripheral nerves treat cancer pain associated with the upper and lower limbs, whereas paravertebral and intercostal blocks treat cancer pain associated with the chest wall and ribs. Finally, alternate drug delivery methods such as intrathecal drug delivery systems concentrate medication at central opioid receptors without affecting the peripheral receptors implicated in unwanted side effects. This article provides an overview of these interventions, including indications, contraindications, and potential complications of advanced interventional pain management options available for the treatment of intractable cancer-related pain.

Practical considerations and patient selection for intrathecal drug delivery in the management of chronic pain

Chronic pain continues to pose substantial and growing challenges for patients, caregivers, health care professionals, and health care systems. By the time a patient with severe refractory pain sees a pain specialist for evaluation and management, that patient has likely tried and failed several nonpharmacologic and pharmacologic approaches to pain treatment. Although relegated to one of the interventions of "last resort", intrathecal drug delivery can be useful for improving pain control, optimizing patient functionality, and minimizing the use of systemic pain medications in appropriately selected patients. Due to its clinical and logistical requirements, however, intrathecal drug delivery may fit poorly into the classic pain clinic/interventional model and may be perceived as a "critical mass" intervention that is feasible only for large practices that have specialized staff and appropriate office resources. Potentially, intrathecal drug delivery may be more readily adopted into larger practices that can commit the necessary staff and resources to support patients' needs through the trialing, initiation, monitoring, maintenance, and troubleshooting phases of this therapy. Currently, two agents - morphine and ziconotide - are approved by the United States Food and Drug Administration for long-term intrathecal delivery. The efficacy and safety profiles of morphine have been assessed in long-term, open-label, and retrospective studies of >400 patients with chronic cancer and noncancer pain types. The efficacy and safety profiles of ziconotide have been assessed in three double-blind, placebo-controlled trials of 457 patients, and safety has been assessed in 1,254 patients overall, with severe chronic cancer, noncancer, and acquired immunodeficiency syndrome pain types. Both agents are highlighted as first-line intrathecal therapy for the management of neuropathic or nociceptive pain. The purpose of this review is to discuss practical considerations for intrathecal drug delivery, delineate criteria for the identification and selection of candidates for intrathecal drug delivery, and consider which agent may be more appropriate for individual patients.

Current perspectives on intrathecal drug delivery

Advances in intrathecal analgesia and intrathecal drug delivery systems have allowed for a range of medications to be used in the control of pain and spasticity. This technique allows for reduced medication doses that can decrease the side effects typically associated with oral or parenteral drug delivery. Recent expert panel consensus guidelines have provided care paths in the treatment of nociceptive, neuropathic, and mixed pain syndromes. While the data for pain relief, adverse effect reduction, and cost-effectiveness with cancer pain control are compelling, the evidence is less clear for noncancer pain, other than spasticity. Physicians should be aware of mechanical, pharmacological, surgical, and patient-specific complications, including possible granuloma formation. Newer intrathecal drug delivery systems may allow for better safety and quality of life outcomes.