Intrathecal infusional analgesia for nonmalignant pain: analgesic efficacy of intrathecal opioid with or without bupivacaine

Recommendations for anesthetic management for intraoperative neuromodulation cases

This paper performs a review of current literature as well as uses our single-center experience to discuss pre-operative, intra-operative and, briefly, postoperative management for dorsal column stimulators (DCSs), dorsal root ganglion (DRG) stimulators, peripheral nerve stimulators (PNSs) and intrathecal pumps. Generally, pre-operative antibiotics are recommended with discontinuation within 24 h postoperatively. For dorsal column and DRG stimulation, monitored anesthesia care or general anesthesia with intra-operative neuromonitoring is recommended; for peripheral nerve stimulation and intrathecal pump implementation, monitored anesthesia care is preferred. There is little information on appropriate anesthetic management during these forms of neuromodulation. More research is necessary to articulate specific pre-operative, intra-operative and postoperative management guidelines and recommendations for dorsal column stimulator, DRG stimulation, PNS and intrathecal pump implantation.

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.

Evaluation of an Intrathecal Drug Delivery Protocol Leads to Rapid Reduction of Systemic Opioids in the Oncological Population

Objective: The article that follows is purposed at demonstrating how IT opioid plus bupivacaine achieves sustained acceptable pain relief while simultaneously rapidly reducing oral morphine equivalents (OME). Background: Cancer patients represent a population with significant morbidity, pain, and limited life expectancy. It is, therefore, vital to achieve satisfactory analgesia quickly and safely. To date, there is limited data in the literature that discusses efficacy of combined intrathecal (IT) medication therapy in reducing systemic opioids in the oncological population. Methods: This was a retrospective analysis that reviewed cancer pain patients from day of IT pump implantation through the six-month postoperative time point. A cohort of 50 oncological patients who had intrathecal drug delivery systems (IDDSs) implanted at Memorial Sloan Kettering Cancer Center between 2017 and 2019 were studied. Median OMEs were the primary modality of analysis for this review. Mean visual analogue scale scores were secondarily reviewed. Results: Median OMEs decreased from 503 preoperative to 105 at six months postoperative time point. Median time to discharge was 6.5 days. Unfortunately, due to malignant mortality, 27 patients did not make it to the 6-month postoperative time point. Discussion: IDDSs with opioid plus bupivacaine represent a safe and efficient route toward expeditious pain relief and decreased OMEs in the cancer pain population.

'Was it worth it?' Intrathecal analgesia for cancer pain: A qualitative study exploring the views of family carers

BACKGROUND

Intrathecal drug delivery is known to reduce pain in patients where conventional systemic analgesia has been ineffective or intolerable. However, there is little information regarding the effects of intrathecal drug delivery on quality of life and function in those with advanced, incurable cancer.

AIM

Retrospective exploration of the views of bereaved carers regarding the physical and psychosocial effects of external tunnelled intrathecal drug delivery in patients with advanced incurable cancer.

DESIGN

Thematic analysis of qualitative interviews with carers of deceased individuals who received percutaneous external tunnelled intrathecal drug delivery as part of their pain management, within two UK centres.

SETTING

A total of 11 carers were recruited from two UK Palliative Care centres. Family carers of adult patients who had received external tunnelled intrathecal drug delivery analgesia for cancer pain and had died between 6 and 48 months prior to contact were included. Carer relatives who were considered likely to be too vulnerable or who had lodged a complaint about treatment within the recruiting department or who had been treated directly by the interviewer were excluded.

RESULTS

In total, 11 interviews took place. The emerging themes were (1) making the decision to have the intrathecal - relatives described desperate situations with severe pain and/or sedation, meaning that the individual would try anything; (2) timing and knowing they were having the best - an increased access to pain and palliative care services, meant carers felt everything possible was being done, making the situation more bearable; (3) was it worth it? - the success of the external tunnelled intrathecal drug delivery was judged on its ability to enable the individual to be themselves through their final illness. Side effects were often considered acceptable, if the external tunnelled intrathecal drug delivery enabled improvements in quality of life.

CONCLUSION

Carers perceived external tunnelled intrathecal drug delivery as most valuable when it improved quality of life towards the end of life, by reducing pain and side effects of conventional systemic analgesia to enable individuals 'to be themselves'. Under these circumstances, the carers judged significant side effects to be acceptable.

The Pharmacology of Spinal Opioids and Ziconotide for the Treatment of Non-Cancer Pain

Background

Intrathecal drug delivery has undergone a revitalization following a better understanding of this delivery route and its pharmacokinetics. Driven by patient safety and outcomes, clinicians are motivated to rethink the traditional spinal infusion pump patient selection criteria and indications. We review the current understanding of the pharmacology of commonly employed intrathecal agents and the clinical relevance.

Methods

Search strategies for data acquisition included Medline database, PubMed, Google scholar, along with international and national professional meeting content, with key words including pharmacology of opioids, intrathecal therapy, ziconotide, pharmacokinetics, and intrathecal drug delivery. The search results were limited to the English language.

Results

Over 300 papers were identified. The literature was condensed and digested to evaluate the most commonly used medications in practice, sto serve as a foundation for review. We review on-label medications: ziconotide and morphine, and off label medications including fentanyl, sufentail, and hydromorphine.

Conclusion

Intrathecal therapy has level-one evidence for use for malignant pain and nonmalignant pain, with continued cost savings and improved safety. To most effectively serve our patients, a clear appreciation for the pharmacology of these commonly employed medication is paramount..

Combined epidural morphine and bupivacaine in the treatment of lumbosacral radicular neuropathic pain: a noncontrolled prospective study

Objective

The aim of this study was to investigate the therapeutic effectiveness of epidural morphine and bupivacaine in patients with chronic lumbosacral radicular neuropathic pain after the cessation of treatment.

Methods

Twenty-two patients with chronic lumbosacral pain with neuropathic features were enrolled. An indwelling catheter was placed into the epidural space, and each patient received an epidural injection of morphine chlorhydrate and bupivacaine up to three times a day. The medication was administered for 4 weeks. The pain intensity score on a 0–10 numeric rating scale (NRS), the total pain rating index rank (PRIr-T), and its coefficients were evaluated before treatment and 1 month after catheter removal. P-value <0.05 was considered statistically significant.

Results

NRS and PRIr-T were significantly reduced at follow-up (P=0.001 and P=0.03, respectively), whereas the parallel evolution of the two scores (r=0.75 and P<0.001, respectively) confirmed significant pain relief lasting up to 1 month after treatment cessation. None of the four pain rating coefficients was significantly modified compared to the others in either responders or nonresponders. Successful clinical outcome (pain reduction >30% in NRS) was reached and maintained in half of the patients at follow-up.

Conclusion

Combined epidural morphine and bupivacaine seems to be effective in the treatment of neuropathic pain.

Interventional therapies for chronic low back pain

OBJECTIVE

Low back pain (LBP) is a highly prevalent condition and one of the leading causes of lost productivity and health-care costs. The objective of this review is to discuss the role of interventional pain procedures and evidence of their effectiveness in treatment of chronic LBP.

METHODS

This is a narrative review examining published studies on interventional procedures for LBP. The rationales, indications, technique, evidence, and complications for the interventional procedures are discussed.

RESULTS

Interventional pain procedures are used extensively in diagnosis and treatment of chronic pain. LBP is multifactorial, and while significant progress has been made in understanding its pathophysiology, this has not resulted in a proportional improvement of functional outcomes. For certain procedures, such as spinal cord stimulation, medical branch blocks and radiofrequency ablations, and epidural steroid injections for radiculopathy, safety, efficacy, and cost-effectiveness in treating LBP have been well studied. For others, such as interventions for discogenic pain, treatment successes have been modest at best.

CONCLUSIONS

Implementation of interventional pain procedures in the treatment framework of LBP has resulted in improvement of pain intensity in at least the short and medium terms, but equivocal results have been observed in functional improvement.

Acute and subchronic antinociceptive effects of nociceptin/orphanin FQ receptor agonists infused by intrathecal route in rats

Severe pain occurs in the context of many diseases and conditions and is a leading cause of disability. Nociceptin/orphanin FQ (N/OFQ) is the endogenous ligand of the N/OFQ peptide (NOP) receptor. This peptidergic system controls pain transmission and in particular spinally administered N/OFQ has robust antinociceptive properties. The aim of this study was to investigate the spinal antinociceptive properties of NOP peptide agonists after acute and subchronic treatment in rats. Doses unable to alter motor coordination were selected. UFP-112 (full NOP agonist) and UFP-113 (partial NOP agonist) were administered intrathecally (i.t.) by spinal catheterization. Acute injection of UFP-112 induced antinociceptive response at lower dosages (0.03-1nmol i.t.) compared to morphine and similar to N/OFQ. UFP-113 was effective in a 0.001-1nmol i.t. dose range. The antinociceptive effects of NOP ligands were no longer evident in rats knockout for the NOP gene, while those of morphine were maintained. The continuous spinal infusion (by osmotic pumps) of 0.1nmol/h UFP-112 and UFP-113 showed antinociceptive action comparable to 1-3nmol/h morphine or N/OFQ. The antinociceptive effect of morphine progressively decreased and was no longer significant after 6 days of treatment. Similar results were obtained with N/OFQ, UFP-112, and UFP-113. The acute i.t. injection of morphine in animals tolerant to N/OFQ and UFP-112 evoked analgesic effects. Neither morphine nor N/OFQ induced antinociceptive effects in morphine- and UFP-113-tolerant rats. In conclusion this study highlights the analgesic efficacy and potency of UFP-112 and UFP-113 underlining the relevance of NOP system in analgesia.

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.

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.

Intrathecal therapy for cancer and nonmalignant pain: patient selection and patient management

Intrathecal drug delivery improves pain relief, reduces suffering, and enhances quality of life in the small proportion of patients who do not respond well to oral analgesics, including oral morphine. Although morphine is the "gold standard," and the only drug approved for intrathecal pain therapy in the United States, off-label use of alternative agents appears promising, particularly in patients with neuropathic pain. Careful patient selection and management are significant determinants of successful treatment outcomes. Patient selection criteria for cancer and nonmalignant pain are similar; however, a more comprehensive psychological and social assessment is required for patients with nonmalignant pain. In addition, all patients (those with cancer or nonmalignant pain) must exhibit a positive response to an epidural or intrathecal screening test. A multidisciplinary team approach, involving psychologists, nurses, physical therapists, social workers, and spiritual leaders should be used to manage patients. Current practices for patient selection and management, screening tests, and dosing guidelines for intrathecal drug delivery systems are discussed.

The effects of long-term intraspinal infusion therapy with noncancer pain patients: evaluation of patient, significant-other, and clinic staff appraisals

Objective. This study examines, in a retrospective fashion, the effects of intraspinal infusion therapy, primarily using opioids, in the treatment of recalcitrant noncancer pain in a sample of 29 consecutive patients. Patients were, on average, 58 years of age having had one surgery, with a pain duration of 221 months. Mean follow-up duration was 31 months. Telephone interviews by a disinterested party were used to obtain follow-up data from patients and their significant others. In addition, clinic staff rated patient improvement. Results. The patients reported an average of 63.4% improvement in pain; 45.5% improvement in activity level; and a 53.8% improvement in "ease" of performing activities. Average pain level on a numerical rating scale decreased from 8.91/10 to 5.03/10. The number of patients reporting a pain level of 5/10 or less increased from 1/29 to 15/29. Patients generally reported long-term benefit to be equal to or greater than that realized during the intrathecal trial. Approximately 86% of patients reported a "good" or "excellent" outcome. Significant-other ratings of improvement correlated more highly with clinic staff than with patients. No statistically significant differences were observed when worker's compensation (WC) patients were compared with nonworker's compensation (NWC) patients. Nearly 50% of the patients reported some type of transient or persistent side effect, mostly related to the infused substance. No mechanical failure of the DAS system was observed. Conclusion. These results in part replicate those from previous studies examining the long-term effects of infusion therapy. Side effects remain fairly common and require continued attention. Their presence, however, did not appear to deter from the patient's overall sense of satisfaction. Acquiring information from significant others and clinic staff may be a useful adjunct in interpreting the overall outcome.

Methadone in the intrathecal treatment of chronic nonmalignant pain resistant to other neuroaxial agents: the first experience

Intrathecal drug delivery is a widely used and effective method of treatment for chronic intractable pain. Unfortunately all currently used agents can not provide adequate pain relief in all patients. A prospective study of neuroaxial methadone was performed in 24 patients, all of whom had failed treatment with multiple previous intrathecal drugs. Thirteen patients experienced improvement of their pain control with methadone, nine continued to receive this agent for 6 months with good pain relief, improved quality of life and no side effects. The final rates of methadone infusion were 2.2 times higher than preceding morphine rates. The only observed possible side effect of methadone was transient blurred vision in one patient. Methadone is a promising alternative neuroaxial agent in the treatment of chronic pain.

Preclinical toxicity study of intrathecal administration of the pain relievers dextrorphan, dextromethorphan, and memantine in the sheep model

Objectives To determine the toxicity window for the continuous intrathecal administration of dextrorphan, dextromethorphan, and memantine via an implanted delivery pump. Materials and Methods Using 48 sheep with programmable continuous intrathecal infusion systems we determined the behavioral, motor, neurological, and histopathological changes produced by a 43-day continuous infusion study of dextrorphan, dextromethorphan, and memantine dissolved in 0.9% NaCl. Daily doses of each N-methyl-D-aspartate (NMDA) antagonist were 0.013, 0.051, 0.203, 0.510, 0.811, and 2.533 mg/kg/day, flow rates ranged from 13.25 ml/day to 0.051 ml/day at a concentration of 10 mg/ml. Control animals received saline in the range of 7.9985 ml/day to 1 ml/day. Conclusions Infusion of saline in the control animals produced no behavioral or motor changes. However, infusion of dextrorphan, dextromethorphan, and memantine at the higher doses (> 0.051 mg/kg/day) produced dose-dependent negative behavioral, motor, and histopathologic changes as indicated by a series of nonparametric statistical analyses. The minimal toxic doses were dextrorphan dose 3, dextromethorphan dose 1 and memantine dose 1. This study suggests that continuous intrathecal infusion of dextrorphan, dextromethorphan, and memantine via an implantable pump system can cause significant toxicities at the higher doses studied.

Characteristics of distribution of morphine and metabolites in cerebrospinal fluid and plasma with chronic intrathecal morphine infusion in humans

BACKGROUND

Despite widespread use of chronic intrathecal (IT) infusions of morphine, there is little systematic human work evaluating the steady state morphine concentrations or cerebrospinal (CSF) chemistry after long-term IT morphine delivery. We sought to address these issues in patients receiving chronic IT morphine infusion.

METHODS

Pain patients with implanted catheters and pumps (range: 127 to 2165 days), receiving a stable dosing (>1 week) of IT morphine by infusion, were entered into the study. The following sequence was performed: (1) estimation of pain score; (2) radiograph localization of catheter tip; (3) percutaneous sampling of lumbar CSF at the L4 to 5 or L5-S1 space. CSF/plasma samples were assayed for chemistry, and morphine and its 3/6 glucuronide metabolites (M3G, M6G) by liquid chromatography mass spectrometry.

RESULTS

Nineteen patients were enrolled. CSF samples were obtained from 16 subjects. Three patients were not included in the primary analysis because 1 catheter was epidural, 1 catheter was fractured, and 1 had a granuloma at the catheter tip. Of the 13 sampled patients, the range of daily doses, rates, and concentrations were 1.6 to 25 mg/d and 0.1 to 1 mL/d, 5 to 50 mg/mL, respectively. The principal observations were as follows: (i) morphine, M3G, and M6G were present in the CSF and plasma and showed a significant regression slope when plotted versus daily dose; (ii) in contrast, the regression slope of the group ratio morphine:M3G:M6G plotted versus daily dose in CSF or plasma was not different from zero; (iii) plotting "normalized" CSF analyte concentration (e.g., concentration at site/daily IT morphine dose) against the segmental distance of the sampling site from the catheter tip revealed a significant decline in concentration of morphine, but not of conjugates as a function of distance from the catheter tip; (iv) plotting CSF protein, glucose, and red and white cell counts versus daily morphine dose or morphine concentration at the sampling site revealed no significant regression; and (v) patients with a catheter failure or a granuloma showed reduced concentrations of morphine in their CSF.

CONCLUSION

Chronic infusion of morphine shows high concentrations, which correlate with the infusion dose and the proximity of the sampling site to the infusion site with no effects on CSF chemistry.

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.

Role of pretrial systemic opioid requirements, intrathecal trial dose, and non-psychological factors as predictors of outcome for intrathecal pump therapy: one clinician's experience with lumbar postlaminectomy pain

OBJECTIVE

Non-psychological parameters may predict pump success.

METHODS

Review was performed on 35 implants for gender, age, pretrial/trial dose, baseline visual analog scale (VAS), and pain location. One-year outcomes were % change VAS/intrathecal dose and medication change. Spearman coefficients correlated pretrial/trial dose, age, baseline VAS, and % change in VAS/intrathecal dose. Wilcoxon Rank-Sum tests correlated gender/pain location and % change in VAS/intrathecal dose. Pretrial/trial dose, baseline VAS, and medication change was tested using Wilcoxon Rank-Sums. Chi-square was used to correlate medication change with gender/pain location. A two-sample t-test compared age and medication change.

RESULTS

Positive correlation between % change VAS and trial dose was noted. Greater age correlated with lower VAS and % dose change. Marginally significant difference in % dose change by pain location was present with higher doses for leg pain.

CONCLUSION

Trial dose, age, and partially pain location are good predictors of pain relief.

Long-term intrathecal morphine and bupivacaine upregulate MOR gene expression in lymphocytes

BACKGROUND

Several studies have shown that opioids may suppress the immune system either by binding to mu-opioid receptors (MOR) expressed in immune cells or by activating these receptors within the central nervous system.

OBJECTIVE

To assess the level of lymphocyte expression of MOR mRNA in patients with chronic non-cancer pain, who were treated with intrathecal morphine or with morphine plus bupivacaine via an intrathecal drug delivery system, and to investigate whether intrathecal morphine and the associated local anesthetic administration influences lymphocyte subpopulations.

METHODS

In total, 29 people [10 controls (age range 59-85 years) and 19 patients (age range 47-89 years) with various chronic non-malignant pain conditions] were enrolled in the study. MOR mRNA levels were evaluated in peripheral lymphocytes, and lymphocyte subsets were determined by direct immunofluorescence using flow cytometry.

RESULTS

After 12 months of treatment with intrathecal morphine (1.5-4 mg/day), there was an increase in MOR mRNA levels in lymphocytes of 65% compared with controls and 47% with pretreatment values. Even higher levels (increase of 142% compared with controls and 135% with pretreatment values) were observed in the patients treated with morphine plus bupivacaine (0.2-0.4 mg/day). Elevation of MOR mRNA levels was confirmed in patients after 24 months of treatment. At this time point, the percentage of natural killer cells was significantly decreased.

CONCLUSION

This preliminary study suggests that opioids must be used with care in patients who are already immunosuppressed by disease or by other, concurrently administered drugs.

Long-term opioid management for chronic noncancer pain

BACKGROUND

Opioid therapy for chronic noncancer pain (CNCP) is controversial due to concerns regarding long-term effectiveness and safety, particularly the risk of tolerance, dependence, or abuse.

OBJECTIVES

To assess safety, efficacy, and effectiveness of opioids taken long-term for CNCP.

SEARCH STRATEGY

We searched 10 bibliographic databases up to May 2009.

SELECTION CRITERIA

We searched for studies that: collected efficacy data on participants after at least 6 months of treatment; were full-text articles; did not include redundant data; were prospective; enrolled at least 10 participants; reported data of participants who had CNCP. Randomized controlled trials (RCTs) and pre-post case-series studies were included.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted safety and effectiveness data and settled discrepancies by consensus. We used random-effects meta-analysis' to summarize data where appropriate, used the I(2) statistic to quantify heterogeneity, and, where appropriate, explored heterogeneity using meta-regression. Several sensitivity analyses were performed to test the robustness of the results.

MAIN RESULTS

We reviewed 26 studies with 27 treatment groups that enrolled a total of 4893 participants. Twenty five of the studies were case series or uncontrolled long-term trial continuations, the other was an RCT comparing two opioids. Opioids were administered orally (number of study treatments groups [abbreviated as "k"] = 12, n = 3040), transdermally (k = 5, n = 1628), or intrathecally (k = 10, n = 231). Many participants discontinued due to adverse effects (oral: 22.9% [95% confidence interval (CI): 15.3% to 32.8%]; transdermal: 12.1% [95% CI: 4.9% to 27.0%]; intrathecal: 8.9% [95% CI: 4.0% to 26.1%]); or insufficient pain relief (oral: 10.3% [95% CI: 7.6% to 13.9%]; intrathecal: 7.6% [95% CI: 3.7% to 14.8%]; transdermal: 5.8% [95% CI: 4.2% to 7.9%]). Signs of opioid addiction were reported in 0.27% of participants in the studies that reported that outcome. All three modes of administration were associated with clinically significant reductions in pain, but the amount of pain relief varied among studies. Findings regarding quality of life and functional status were inconclusive due to an insufficient quantity of evidence for oral administration studies and inconclusive statistical findings for transdermal and intrathecal administration studies.

AUTHORS' CONCLUSIONS

Many patients discontinue long-term opioid therapy (especially oral opioids) due to adverse events or insufficient pain relief; however, weak evidence suggests that patients who are able to continue opioids long-term experience clinically significant pain relief. Whether quality of life or functioning improves is inconclusive. Many minor adverse events (like nausea and headache) occurred, but serious adverse events, including iatrogenic opioid addiction, were rare.

The Role of Interventional Therapies in Cancer Pain Management

Cancer pain is complex and multifactorial. Most cancer pain can be effectively controlled using analgesics in accordance to the WHO analgesic ladder. However, in a small but significant percentage of cancer patients, systemic analgesics fail to provide adequate control of cancer pain. These cancer patients can also suffer from intolerable adverse effects of drug therapy or intractable cancer pain in advance disease. Though the prognosis of these cancer patients is often very limited, the pain relief, reduced medical costs and improvement in function and quality of life from a wide variety of available interventional procedures is extremely invaluable. These interventions can be used as sole agents or as useful adjuncts to supplement analgesics. This review will discuss interventional procedures such as epidural and intrathecal drug infusions, intrathecal neurolysis, sympathetic nervous system blockade, nerve blocks, vertebroplasty and the more invasive neurosurgical procedures. Intrathecal medications including opioids, local anaesthetics, clonidine, and ziconotide will also be discussed. Key words: Intractable pain, Intrathecal analgesia, Neurolysis

Cost-effectiveness of ziconotide in intrathecal pain management for severe chronic pain patients in the UK

OBJECTIVE

To examine the cost-effectiveness of using intrathecal ziconotide in the treatment of severe chronic pain compared to best supportive care for patients with intractable chronic pain in the United Kingdom.

METHODS

Using a simulation model, the analysis evaluated the cost and health economic consequences of using ziconotide as a treatment for severe chronic pain. The modelled population and clinical data were based on a randomised controlled trial in which the main outcome was reduction in pain as measured by the visual analogue scale of pain intensity (VASPI). Resource use data were elicited using a modified Delphi panel and costed using published sources. Utility values were derived from a separate research study. The main outcome measure was the cost per quality-adjusted life-year (QALY). Extensive scenario analysis was conducted to evaluate parameter uncertainty.

RESULTS

Overall, findings were robust to most assumptions. The cost-effectiveness of ziconotide compared to best supportive care (BSC) was pound 27,443 per QALY (95% CI pound 18,304-38,504). Scenarios were investigated in which discount rates, the time horizon, the threshold for qualifying as a responder, pump-related assumptions, utilities, ziconotide drug dose, and the patient discontinuation rate with ziconotide were varied. The most sensitive parameter was the dosage of ziconotide: using the lower and upper bounds of the average ziconotide dosage observed in the long-term open-label study changed the incremental cost-effectiveness ratio (ICER) to pound 15,500 [pound 8206-25,405] and pound 44,700 [pound 30,541-62, 670].

CONCLUSIONS

Ziconotide may offer an economically feasible alternative solution for patients for whom current treatment is inappropriate or ineffective. The main study limitation is that some model inputs, mainly related to resource use, are based on assumptions or expert interviews.

Interventional pain treatments for cancer pain

Cancer pain is prevalent and often multifactorial. For a segment of the cancer pain population, pain control remains inadequate despite full compliance with the WHO analgesic guidelines including use of co-analgesics. The failure to obtain acceptable pain or symptom relief prompted the inclusion of a fourth step to the WHO analgesic ladder, which includes advanced interventional approaches. Interventional pain-relieving therapies can be indispensable allies in the quest for pain reduction among cancer patients suffering from refractory pain. There are a variety of techniques used by interventional pain physicians, which may be grossly divided into modalities affecting the spinal canal (e.g., intrathecal or epidural space), called neuraxial techniques and those that target individual nerves or nerve bundles, termed neurolytic techniques. An array of intrathecal medications are infused into the cerebrospinal fluid in an attempt to relieve refractory cancer pain, reduce disabling adverse effects of systemic analgesics, and promote a higher quality of life. These intrathecal medications include opioids, local anesthetics, clonidine, and ziconotide. Intrathecal and epidural infusions can serve as useful methods of delivering analgesics quickly and safely. Spinal delivery of drugs for the treatment of chronic pain by means of an implantable drug delivery system (IDDS) began in the 1980s. Both intrathecal and epidural neurolysis can be effective in managing intractable cancer-related pain. There are several sites for neurolytic blockade of the sympathetic nervous system for the treatment of cancer pain. The more common sites include the celiac plexus, superior hypogastric plexus, and ganglion impar. Today, interventional pain-relieving approaches should be considered a critical component of a multifaceted therapeutic program of cancer pain relief.

Intrathecal drug therapy for long-term pain management

PURPOSE

The use, safety, and efficacy of intrathecal medication administration with implantable pumps for cancer and chronic pain management are reviewed.

SUMMARY

Implanted intrathecal drug-delivery systems (IDDSs) are used for long-term management of persistent, severe pain despite a multimodal approach with conventional pain treatment options. Currently, consensus papers published in the literature are used as guidelines for determining patient selection and medication administration, because there is a lack of supporting evidence from randomized, controlled, clinical trials. Pharmacists have a critical role in the safe use of intrathecal medication. Most of the medication concentrations and combinations administered through IDDSs are not commercially available and therefore must be compounded in a pharmacy. Medications commonly administered through IDDSs include opioids, local anesthetics, clonidine, baclofen, and ziconotide. It is important for pharmacists who prepare products for IDDSs to understand the pharmacology, adverse effects, and concentration limitations of each medication in order to prevent adverse events related to postoperative subarachnoid hemorrhage, infection, catheter-tip inflammatory masses, withdrawal, and overdose. Pharmacists play an important role in maintaining quality assurance of intrathecal drug use, including the use of standard procedures for ordering and compounding medications, documentation of patient education, and monitoring of patient outcomes.

CONCLUSION

The use of long-term intrathecal drug delivery for the treatment of intractable pain or intolerable medication adverse effects has expanded to include the treatment of patients with chronic or cancer-related pain. Important considerations for the use of intrathecal drug therapy include the appropriate selection of patients, delivery systems, and medications, as well as potential complications of therapy and quality-assurance measures necessary to ensure patient safety.

Intrathecal analgesia

Since the first use of intrathecal (IT) drug infusion systems in the early 1980s, these delivery systems have undergone numerous revisions making them more tolerable, easier to program, and longer lasting. Concurrent with technological advances, the indications for IT pump placement have also been continuously evolving, to the point where the most common indication is now noncancer pain. This article provides an evidence-based review of the indications, efficacy, and complications of IT drug therapy for the most commonly administered spinal analgesics.

Continuous Intrathecal Morphine Infusion in Patients With Vertebral Fractures Due to Osteoporosis

OBJECTIVES

Vertebral fractures are the most common consequences of severe osteoporosis. The chronic pain from collapse of osteoporotic vertebrae affects quality of life (QOL) and autonomy of patients. The management of pain with oral or transdermal opiates can cause severe side effects. Continuous intrathecal administration of morphine via an implantable pump might represent an alternative therapy to conventional oral or transdermal administration of opioids and has some advantages and disadvantages for pain relief and improvement in QOL when compared with conventional opioid delivery. It is our objective to report our experience using intrathecal delivery of analgesics in a population of patients with refractory pain due to vertebral fractures.

MATERIALS AND METHODS

In 24 patients, refractory to conventional delivery of opioids, we used intrathecal analgesic therapy. To test for efficacy and improvement in QOL, we administered the visual analog scale for pain and the Questionnaire of the European Foundation of Osteoporosis (QUALEFFO). Before patients were selected for pump implantation, an intraspinal drug delivery trial was performed to monitor side effects and responses to intrathecal therapy.

RESULTS

Significant pain relief was obtained in all implanted patients. Using the QUALEFFO, we observed significant improvement of all variables such as quality of daily life, domestic work, ambulation, and perception of health status, before and after 1 year after pump implantation. With intrathecal morphine infusion, none of the 24 patients required additional systemic analgesic medication. The mean morphine dose during the spinal trial was 11.28 mg/d, 7.92 mg/d at pump implantation, and 16.32 mg/d at 1-year follow-up.

CONCLUSIONS

Our results show that intrathecal administration of morphine efficiently relieves the symptoms of pain and improves QOL. Continuous intrathecal administration of morphine appears to be an alternative therapy to conventional analgesic drug delivery and has advantages in those patients who have severe side effects with systemic administration of analgesics.

Intrathecal opioids for intractable pain syndromes

For more than 20 years intrathecal opioid application with implantable pumps is an option for selected patients with malignant as well as non-malignant pain. In general, most types of pain should be treatable by opioid medication. However, the associated systemic side-effects such as nausea, vomiting, constipation or the risk of suppression of the central nervous system hinder the application of oral or intravenous opioid therapy as a sole, widely applicable treatment. Causes of non-malignant pain that may represent an indication for intrathecal drug-delivery systems include: failed back syndrome, neuropathic pain, axial spinal pain, complex regional pain syndrome, diffuse pain, brachial plexitis, central pain, failed spinal cord stimulation (SCS) therapy, arachnoiditis, poststroke pain, spinal cord injury pain and peripheral neuropathy. Due to the proximity to the receptor sites, the therapeutic effect of intrathecal drug application lasts longer and the rate of systemic side effects is reduced. Before definitive pump implantation, the therapeutic effect of intrathecal opioid therapy is tested with an external pump. If there is no clear and satisfactory effect in this trial application, pump implantation is not indicated. In our patients, with a follow-up exceeding 3 years, the reduction of non-malignant pain (assessed with the Visual Analogue Scale, VAS) was good or excellent (pain decrease >50%) in 71.3% of the patients, fair (VAS 5-6) in 19.8% and poor (VAS 7-10) in 8.9%. After 3 years of continuous treatment, we observed catheter-related technical problems (catheter dislocation, obstruction, kinking, disconnection or rupture) in 17 of 165 patients. Pump malfunctions were very rare (8 of 165 cases) and limited to older pump types. Reversible, specific drug-related side effects of long-term therapy with intrathecal pumps developed in 32 of the 165 patients. In our series, the mean serum/cerebrospinal fluid (CSF) concentration ratio for morphine was 1/3000, which explains the low rate of systemic side effects. Local diffusion difficulties in CSF cause an uneven distribution of morphine in CSF. Therefore the clinical effect is markedly influenced by the position of the catheter tip, a fact that should be kept in mind during catheter implantation. Intrathecal drug application is cost effective and can significantly improve the quality of life in selected patients. An intensive training in this method and awareness of its specific complications is necessary for everyone to participate in the consulting and implanting team. Pumps for chronic intrathecal opioid application should only be implanted in specialized centers.

Intrathecal analgesia

Since the first use of intrathecal (IT) drug infusion systems in the early 1980s, these delivery systems have undergone numerous revisions making them more tolerable, easier to program, and longer lasting. Concurrent with technological advances, the indications for IT pump placement have also been continuously evolving, to the point where the most common indication is now noncancer pain. This article provides an evidence-based review of the indications, efficacy, and complications of IT drug therapy for the most commonly administered spinal analgesics.

Programmable intrathecal opioid delivery systems for chronic noncancer pain: a systematic review of effectiveness and complications

OBJECTIVES

We conducted a systematic review of the literature on the effectiveness and complications of programmable intrathecal opioid and ziconotide drug delivery systems (IDDS) for patients with chronic noncancer pain.

METHODS

We searched MEDLINE, Cochrane, and other bibliographic databases to identify English-language journal articles reporting programmable IDDS complications or effects on pain or functioning. Additional study methodology criteria were applied for the effectiveness review. Two authors independently abstracted data from each included article.

RESULTS

Six articles met the inclusion criteria for the effectiveness and complications reviews, and 4 others met the criteria only for the complications review; none were randomized trials or of ziconotide. All 6 articles reviewed for effectiveness reported improvement in pain and functioning on average among patients who received a permanent IDDS. Two articles reported the proportion of patients with > or =50% improvement in pain at 6 months (38%, 56%) and 2 at longer follow-ups (30%, 44%). Intrathecal morphine-equivalent doses increased over time. The most commonly reported permanent IDDS drug side effects were nausea/vomiting (mean rate weighted by sample size=33%), urinary retention (24%), and pruritus (26%). Catheter problems were also reported commonly. Rare but serious complications included intrathecal catheter tip granulomas.

CONCLUSIONS

The studies reviewed found improvement in pain and functioning on average among patients with chronic noncancer pain who received permanent IDDS. However, their methodologic limitations preclude conclusions concerning the effectiveness of this technology long-term and as compared with other treatments. Drug side effects and hardware complications were common. Suggestions are made for methodologic improvements in future studies.