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

Controversies in intrathecal drug delivery for cancer pain

Pain and suffering related to cancer are challenging issues that continue to deserve consideration for treatment optimization. Advances in analgesic management and control of the underlying cancer have improved symptom management, yet many patients still suffer from uncontrolled pain. Intrathecal drug delivery has an established role in the management of refractory cancer pain, but there are significant knowledge gaps in our understanding and application of this therapy. This review addresses several areas of controversy, including the importance of intrathecal catheter tip location, the necessity of an intrathecal trial and the role of intrathecal ziconotide and local anesthetics. In each area, the evidence is discussed, with an emphasis on presenting practical clinical guidance and highlighting deficiencies in our knowledge that are worthy of future investigation.

Intrathecal Drug Delivery: Advances and Applications in the Management of Chronic Pain Patient

Advances in our understanding of the biology of spinal systems in organizing and defining the content of exteroceptive information upon which higher centers define the state of the organism and its role in the regulation of somatic and automatic output, defining the motor response of the organism, along with the unique biology and spatial organization of this space, have resulted in an increased focus on therapeutics targeted at this extracranial neuraxial space. Intrathecal (IT) drug delivery systems (IDDS) are well-established as an effective therapeutic approach to patients with chronic non-malignant or malignant pain and as a tool for management of patients with severe spasticity and to deliver therapeutics that address a myriad of spinal pathologies. The risk to benefit ratio of IDD makes it a useful interventional approach. While not without risks, this approach has a significant therapeutic safety margin when employed using drugs with a validated safety profile and by skilled practioners. The present review addresses current advances in our understanding of the biology and dynamics of the intrathecal space, therapeutic platforms, novel therapeutics, delivery technology, issues of safety and rational implementation of its therapy, with a particular emphasis upon the management of pain.

Narrative review of intrathecal drug delivery (IDD): indications, devices and potential complications

The management of chronic refractory pain (non-neoplastic and cancer-related pain) remains a therapeutic challenge. The continuous intrathecal (IT) administration of drugs may play an important role in the possible management options. Intrathecal drug delivery devices (IDDDs) may be effective for patients with refractory chronic pain. Therefore, they may be adopted for non-oncologic pain in patients with compression fractures, spondylolisthesis, spondylosis, back surgery failure syndrome and spinal stenosis. Oncologic patients can benefit from these treatments in a variable way according to tumor characteristics, prognosis, periprocedural imaging and risk of disease progression. In this review, we describe the most commonly used drugs (opioids and non-opioids), their pharmacokinetic and pharmacodynamic features and indications of use. The most used drugs are morphine, hydromorphone, fentanyl, methadone, bupivacaine, clonidine, and ketamine. Patient evaluation before the device implantation should be based on clinical examination, medical records assessment and psychometric evaluation. The infusion pumps available on the market are both non-programmable (with continuous IT deliver of drugs) and programmable (with variable deliver of drugs according to their flow rate). Moreover, we describe the procedure of implantation and the potential complications of IT drug delivery (such as bleeding, infection, loss of cerebrospinal fluid, wound seroma, loss of catheter pump propellant).

Association Between Oral Pain Medications and Intrathecal Opioid Dose Escalation: A Retrospective Analysis

OBJECTIVES

Patients treated with intrathecal therapy frequently require opioid dose increases to maintain analgesia. The kinetics of intrathecal opioid dose escalation are poorly understood. We hypothesized that antidepressant use, antiepileptic use, and lower baseline oral opioid intake prior to intrathecal pump implantation will be protective against intrathecal opioid dose escalation.

MATERIALS AND METHODS

Targeted drug delivery medication doses were collected from patients who had an intrathecal pump implanted between 2007 and 2016. From a sample size of 136 patients, the association between antidepressant, antiepileptic, and oral opioid use with intrathecal dose escalation was assessed using statistical models.

RESULTS

Individuals using an antiepileptic had an estimated ratio of means (97.5% CI) of opioid consumption of 0.91 (97.5% CI: [0.48, 1.73], p = 0.74) at six months, 0.83 ([0.43, 1.58], p = 0.51) at 12 months, and 0.77 ([0.40, 1.45], p = 0.36) at 24 months. Patients prescribed antidepressants had an estimated ratio of means (97.5% CI) of 1.43 ([0.77, 2.65], p = 0.19) at six months, 1.41 ([0.76, 2.63], p = 0.22) at 12 months, and 1.33 ([0.70, 2.51], p = 0.31) at 24 months. In our secondary analysis of pre-implant oral opioid use, patients treated with high oral opioid doses had a similar pattern of intrathecal dose escalation when compared to patients using low doses of oral opioids.

CONCLUSIONS

Use of antiepileptics, antidepressants, or low oral opioid doses was not associated with attenuation of intrathecal dose escalation. Intrathecal opioid dose escalation was observed to occur similarly, regardless of baseline oral analgesics concomitantly employed.

Intrathecal Drug Delivery

Targeted intrathecal (IT) drug delivery systems (IDDS) are well established as an effective treatment of patients with chronic nonmalignant or malignant pain, and as a tool for management of patients with severe spasticity. The risk to benefit ratio of IDD makes it a relatively safe therapy for both cancer- and noncancer-related pain, but it is not free of risks, so it should be managed at specific centers. Recent technological advances, new therapeutic applications, reported complications, and the costs as well as maintenance required for this therapy require the need to stay up to date about new recommendations that may improve outcomes. This chapter reviews all technological issues regarding IDDS implantation with follow-up and pharmacological recommendations published during recent years that provide evidence-based decision-making process in the management of chronic pain and spasticity in patients.

Intrathecal Trialing of Continuous Infusion Combination Therapy With Hydromorphone and Bupivacaine in Failed Back Surgery Patients

OBJECTIVES

Intrathecal (IT) trial is a prognostic interventional pain management procedure employed to determine the potential success of treating intractable pain with an implantable infusion device system. There is a dearth of data regarding trials with continuous infusion of combination therapy (e.g. opioid combined with local anesthetic). The objective of the this study was to determine the overall outcomes of continuous infusion IT trials and factors influencing long-term success of IT therapy in patients with chronic intractable pain post-laminectomy.

MATERIALS AND METHODS

This is a retrospective analysis of all patients with lumbar failed back surgery syndrome (FBSS) who were trialed with a combination of hydromorphone and bupivacaine with a temporary externalized IT catheter from March 2007 to June 2014.

RESULTS

From a cohort of 62 patients fulfilling the inclusion criteria, 54 (87.10%) patients had successful IT trials. No significant differences were found between successful and failed trial patients with regards to age, sex, pre-trial pain numeric rating scale scores, pre-trial morphine equivalent daily dose, or trial dosages. Significant positive correlations were found between pretrial oral opioid intake and end of trial hydromorphone dose and hydromorphone dose escalation at 12 months and 24 months.

CONCLUSIONS

Patients with refractory low back pain due to FBSS who underwent successful combination IT trial with hydromorphone and bupivacaine infused through a temporary IT catheter had significantly improved pain intensity scores following permanent implant. Higher pre-trial MEDD was correlated with higher trial and post-implant opioid doses and higher rates of opioid dose escalation post-implant.

Intrathecal pain management: a team-based approach

Objective

Physician assistants (PAs), nurse practitioners (NPs), and registered nurses (RNs) provide professional services on pain management teams. This review provides an overview of the practical management of chronic pain with intrathecal (IT) therapy using an interprofessional approach (eg, physicians and other health care professionals), with a focus on the contributions of PAs, NPs, and RNs.

Methods

Narrative review based on literature searches of the Medline database and treatment guidelines on the use of IT therapy in the management of patients with chronic pain.

Results

The specific roles and responsibilities of PAs, NPs, and RNs in the management of patients receiving IT therapy vary by practice. In many pain treatment centers, PAs, NPs, and RNs are responsible for patient education, postimplant maintenance, and ongoing supportive care of patients receiving IT therapy. Topics that we address include patient selection, patient expectations and goal setting, medication selection, outcome assessment, and treatment adjustment. Currently, morphine and ziconotide (a nonopioid, selective N-type calcium channel blocker) are the only agents approved by the US Food and Drug Administration for IT analgesia. We provide relevant information on the dosing, titration, and adverse effect management of these medications for PAs, NPs, and RNs responsible for administering IT therapy.

Conclusion

PAs, NPs, and RNs are valuable members of IT pain management teams. Treatment success requires ongoing monitoring of efficacy and adverse effects, with corresponding adjustments to medication selection and dosing, in addition to good communication among the health care professionals involved in patient care.

The Polyanalgesic Consensus Conference (PACC): Recommendations for Trialing of Intrathecal Drug Delivery Infusion Therapy

INTRODUCTION

Intrathecal (IT) drug infusion is an appropriate and necessary tool in the algorithm to treat refractory cancer and noncancer pain. The decision-making steps/methodology for selecting appropriate patients for implanted targeted drug delivery systems is controversial and complicated. Therefore, a consensus on best practices for determining appropriate use of IT drug infusion may involve testing/trialing this therapy before implantation.

METHODS

This current Polyanalgesic Consensus Conference (PACC) update was designed to address the deficiencies and emerging innovations since the previous PACC convened in 2012. A literature search identified publications available since the previous PACC publications in 2014, and relevant sources were contributed by the PACC members. After reviewing the literature, the panel determined the evidence levels and degrees of recommendations. The developed consensus was ranked as strong (>80%), moderate (50-79%), or weak (<49%).

RESULTS

The trialing for IT drug delivery systems (IDDS) remains an area of continued controversy. The PACC recommendations for trialing are presented in 34 consensus points and cover trialing for morphine, ziconotide, and medication admixtures; starting doses and titration practices; measurements of success; trial settings and monitoring; management of systemic opioids during trialing; and the role of psychological evaluation. Finally, the PACC describes clinical scenarios in which IT trialing is required or not required.

CONCLUSION

The PACC provides consensus guidance on best practices of trialing for IDDS implants. In addition, the PACC recommends that no trial may be required in certain patient populations.

Trialing and Maintenance Dosing Using a Low-Dose Intrathecal Opioid Method for Chronic Nonmalignant Pain: A Prospective 36-Month Study

OBJECTIVE

To evaluate low-dose intrathecal opioid trialing and maintenance with regard to analgesia and psychometric functional capacity.

MATERIALS AND METHODS

Prospective cohort of subjects offered, trialed and maintained using low-dose opioid therapy via an intrathecal drug delivery system. Analgesia, measured by visual analog scale and the Global Pain Scale, and function, measured by Multidimensional Pain Inventory and Global Pain Scale, are evaluated. Population analysis by age, gender, oral opioid dose, diagnosis, and pain type is reported.

RESULTS

Fifty-eight subjects enrolled in the 36-month evaluation period with mean opioid intrathecal opioid dose less than 350 μg per day of morphine equivalent utilized. Primary nociceptive pain type were associated with lower intrathecal opioid doses and improved visual analog scale pain rating and improved pain severity and interference on the Multidimensional Pain Inventory.

CONCLUSIONS

This study adds to the growing body of literature suggesting that low-dose intrathecal analgesia without oral opioid supplementation can be efficacious. It appears that this approach may achieve analgesia with lower doses in those with primary nociceptive pain type.

A Prospective, Randomized, Single-Blinded, Head-to-Head Long-Term Outcome Study, Comparing Intrathecal (IT) Boluses With Continuous Infusion Trialing Techniques Prior to Implantation of Drug Delivery Systems (DDS) for the Treatment of Severe Intractable Chronic Nonmalignant Pain

OBJECTIVE

The study aims to compare intrathecal (IT) boluses to continuous infusion trialing techniques prior to implantation of drug delivery systems (DDS) for the treatment of severe intractable chronic nonmalignant pain.

DESIGN

This is a prospective, randomized, head-to-head long-term outcome study.

MATERIALS AND METHODS

Forty patients with comparable patient demographics were randomly assigned to two cohorts. Cohort A trialed with intermittent boluses; Cohort B trialed with continuous infusion. One patient failed trial in each group. Nineteen patients were implanted in each group. Follow-up was for 36 months with intervals at 6, 12, 18, 24, 36 months. The Brief Pain Inventory was used was used for assessment.

OUTCOME MEASURES

We used the Brief Pain Inventory to measure pain (worst and average), physical function (walking, normal work, and general activity), behavioral function (mood, sleep, and relations with others), IT dose, and oral opioid use.

RESULTS

We observed statistically significant reduction in pain and improvement of function in both cohorts following DDS implantation throughout the observation period. The IT dose remained virtually unchanged throughout as well, with overall limited dose escalation. Oral opioid use was significantly reduced. There was no statistically significant difference in prediction of trial success or long-term outcomes between the two cohorts.

CONCLUSION

Low-dose IT opioids via DDS can provide significant and long-lasting reduction in pain, and improvement in function (physical and behavioral) for patients with chronic nonmalignant pain. The two trialing techniques tested, intermittent boluses, and continuous infusion delivered intrathecally showed no clinical significance difference in terms of predicting trial success or long-term outcomes.

Programmable intrathecal pumps for the management of chronic pain: recommendations for improved efficiency

The management of chronic pain can be very challenging. Often, physicians employ intrathecal (IT) drug delivery systems as a last resort to relieve intractable pain. The system consists of an implantable pump that stores and delivers medication through a catheter to the IT space. Programmability is achieved by positioning an external devise over the implanted pump to change the mode of drug delivery. The innovations in programmable IT drug delivery systems are expanding more rapidly than ever before. Unfortunately, the rapid expansion is accompanied by a lack of prospective randomized trials examining these new options. In an effort to improve results and reduce side effects, publications by experts or expert consensus panels provide guidance for the community. The purpose of this article is to provide a summary of high interest topics in recent publications.

The effect of sedation on the accuracy and treatment outcomes for diagnostic injections: a randomized, controlled, crossover study

BACKGROUND AND OBJECTIVE

Diagnostic injections are used to diagnose myriad pain conditions, but are characterized by a high false-positive rate. One potential cause of inaccurate diagnostic blocks is the use of sedation. We sought to determine the effect of sedation on the validity of diagnostic injections.

DESIGN

Randomized, crossover study in which 73 patients were allocated to receive a diagnostic sacroiliac joint or sympathetic nerve block performed either with or without sedation using midazolam and fentanyl. Those who obtained equivocal relief, good relief lasting less than 3 months, or who were otherwise deemed good candidates for a repeat injection, received a subsequent crossover injection within 3 months (N = 46).

SETTING AND PATIENTS

A tertiary care teaching hospital and a military treatment facility.

RESULTS

In the primary crossover analysis, blocks performed with sedation resulted in a larger mean reduction in pain diary score than those done without sedation (1.2 [2.6]; P = 0.006), less procedure-related pain (difference in means 2.3 [2.5]; P < 0.0001), and a higher proportion of patients who obtained > 50% pain relief on their pain diaries (70% vs. 54%; P = 0.039). The increased pain reduction was not accompanied by increased satisfaction (sedation mean 3.9 [1.1] vs. 3.7 [1.3]; P = 0.26). Similar findings were observed for the parallel group (N = 73) and omnibus (all sedation vs. no sedation blocks, N = 110) analyses. No differences in outcomes were noted between the use and non-use of sedation at 1-month.

CONCLUSIONS

The use of sedation during diagnostic injections may increase the rate of false-positive blocks and lead to misdiagnoses and unnecessary procedures, but has no effect on satisfaction or outcomes at 1-month.

Polyanalgesic Consensus Conference--2012: recommendations on trialing for intrathecal (intraspinal) drug delivery: report of an interdisciplinary expert panel

INTRODUCTION

Trialing for intrathecal pump placement is an essential part of the decision-making process in placing a permanent device. In both the United States and the international community, the proper method for trialing is ill defined.

METHODS

The Polyanalgesic Consensus Conference (PACC) is a group of well-published experienced practitioners who meet to update the state of care for intrathecal therapies on the basis of current knowledge in the literature and clinical experience. Anexhaustive search is performed to create a base of information that the panel considers when making recommendations for best clinical practices. This literature, coupled with clinical experience, is the basis for recommendations and for identification of gaps in the base of knowledge regarding trialing for intrathecal pump placement.

RESULTS

The panel has made recommendations for the proper methods of trialing for long-term intrathecal drug delivery.

CONCLUSION

The use of intrathecal drug delivery is an important part of the treatment algorithm for moderate to severe chronic pain. It has become common practice to perform a temporary neuroaxial infusion before permanent device implantation. On the basis of current knowledge, the PACC has developed recommendations to improve care. The need to update these recommendations will be very important as new literature is published.