Intrathecal Morphine Infusion Therapy in Management of Chronic Pain: Present and Future Implementation in Korea

Spinal Injections: A Narrative Review from a Surgeon's Perspective

Spinal pain is one of most frequent complaints of the general population, which can cause decreased activities of daily living and absence from work. Among numerous therapeutic methods, spinal injection is one of the most effective treatments for spinal pain and is currently widely applied in the clinical field. In this review, spinal injection is discussed from a surgeon's perspective. Recently, although the number of spinal surgeries has been increasing, questions are arising as to whether they are necessary. The failure rate after spinal surgery is high, and its long-term outcome was reported to be similar to spinal injection. Thus, spinal surgeries should be performed conservatively. Spinal injection is largely divided into diagnostic and therapeutic blocks. Using diagnostic blocks, such as the diagnostic selective nerve root block, disc stimulation test, and diagnostic medial branch block (MBB), the precise location causing the pain can be confirmed. For therapeutic blocks, transforaminal nerve root injection, therapeutic MBB, and percutaneous epidural neuroplasty are used. When unbearable spinal pain persists despite therapeutic spinal injections, spinal surgeries can be considered. Spinal injection is usefully used to identify the precise location prior to a patient undergoing injection treatment or surgery and can reduce pain and improve quality of life, and help to avoid spinal surgery. Pain physicians should treat patients with spinal pain by properly utilizing spinal injection.

Cost-Effectiveness and Cost-Utility Analyses in Thailand of Continuous Intrathecal Morphine Infusion Compared with Conventional Therapy in Cancer Pain: A 10-year Multicenter Retrospective Study

Background

Because of the high initial cost of intrathecal drug delivery (ITDD) therapy, this study investigated the cost-effectiveness and cost-utility of ITDD therapy in refractory cancer pain management in Thailand over the past 10 years.

Methods

The retrospective study was conducted in patients with cancer pain who underwent ITDD therapy from January 2011 to 2021 at three university hospitals. Clinical outcomes included the numerical rating scale (NRS), Palliative Performance Scale, and the EQ-5D. The direct medical and nonmedical as well as indirect costs were also recorded. Cost-effectiveness and cost-utility analyses were performed comparing ITDD therapy with conventional therapy (extrapolated from costs of the same patient before ITDD therapy) from a societally oriented economic evaluation.

Results

Twenty patients (F:M: 10:10) aged 60 ± 15 years who underwent implantation of an intrathecal percutaneous port (IT port; n = 15) or programmable intrathecal pump (IT pump; n = 5) were included. The median survival time was 78 (interquartile range = 121-54) days after ITDD therapy. At 2-month follow-up, the incremental cost-effectiveness ratio (ICER)/pain reduction of an IT port (US$2065.36 (CA$2829.54)/2-point NRS reduction/lifetime) was lower than for patients with an IT pump (US$5479.26 (CA$7506.58)/2-point NRS reduction/lifetime) compared with continued conventional therapy. The ICER/quality-adjusted life years (QALYs) gained for an IT port compared with conventional treatment was US$93,999.31(CA$128,799.06)/QALY gained, which is above the cost-effectiveness threshold for Thailand.

Conclusion

The cost-effectiveness and cost-utility of IT port therapy for cancer pain was high relative to the cost of living in Thailand, above the cost-effectiveness threshold. Prospective cost analysis studies enrolling more patients with diverse cancers that investigate the benefit of early ITDD therapy with devices over a range of prices are warranted.

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

OBJECTIVE

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

DESIGN

A retrospective cohort study with a customized claims database.

SETTING

In a university-based hospital.

SUBJECTS

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Comparison of external system and implanted system in intrathecal therapy for refractory cancer pain in China: A retrospective study

INTRODUCTION

Intrathecal therapy (ITT) via an implanted system was demonstrated for the treatment of refractory cancer pain for decades. Recently, the dissemination of ITT is enhanced in an external system way in Asia for a lower implantation cost. This study compares the efficacy, safety, and cost of the two ITT systems in refractory cancer pain patients in China.

METHODS

One hundred and thirty-nine cancer pain patients who underwent implantation of the ITT system were included. One hundred and three patients received ITT via the external system (external group), while 36 patients received ITT via the implanted system (implanted group). A 1:2 propensity score matching procedure was used to yield a total of 89 patients for the final analysis. Medical records of included patients were retrospectively reviewed and pain scores, incidences of complications, and costs were compared.

RESULTS

ITT via the external system provided pain relief as potent as ITT via the implanted system but was less time-consuming in the implantation phase (13 vs. 19 days, p < .01). Nausea/vomiting and urinary retention were the most frequent adverse events in both external and implanted groups (32.14%, 16.07% vs. 36.36%, 21.21%). No significant difference was found in the incidences of all kinds of complications. Compared to the implanted group, the external group cost less for the initial implantation (7268 vs. 26,275 US dollar [USD], p < .001) but had a significant higher maintenance cost (606.62 vs. 20.23 USD calculated monthly, p < .001).

CONCLUSIONS

ITT via the external system is as effective and safe as that via the implanted system and has the advantage of being cheap in the upfront implantation but costs more during the maintenance process in China.

Intrathecal Morphine Infusion Therapy via a Percutaneous Port for Refractory Cancer Pain in China: An Efficacy, Safety and Cost Utilization Analysis

Purpose

Intrathecal morphine infusion therapy via a percutaneous port (IMITPP) has been used widely for its relatively low initial cost. However, there is scarce knowledge about IMITPP. In this study, we sought to evaluate efficacy, complications, and the interval required to achieve the cost equivalence of IMITPP in patients with refractory cancer pain in China.

Patients and Methods

A retrospective chart review was conducted on cancer patients who had received IMITPP at our hospital between April 2017 and April 2019. Data from the numeric pain rating scale and Karnofsky performance scores, and complications and costs related to IMITPP were collected from medical records. Daily analgesic costs before and after IMITPP were calculated based on the doses of opioids on admission and at discharge, respectively. The doses of systemic opioids before IMITPP were stratified into very high doses [VHD, oral morphine equivalent dose (OMED) >599 mg/day], high doses (HD, 300 mg/day ≤ OMED ≤ 599 mg/day), and regular doses (RD, OMED < 300 mg/day).

Results

Intrathecal morphine infusion therapy via a percutaneous port provided significant pain relief, but impaired activities of daily living in patients with refractory cancer pain. The commonly reported complications included nausea/vomiting and urinary retention, most of which were managed with symptomatic therapies. The median interval required to achieve cost equivalence was 11.44 months. The median intervals of VHD group and HD group were significantly shorter than that of RD group.

Conclusion

Intrathecal morphine infusion therapy via a percutaneous port provided effective cancer pain management without causing serious complications. Patients with higher doses of systemic opioids would economically benefit from IMITPP in a shorter time.

Super analgesia of intrathecal morphine may be related to ABCB1 (MDR1) gene polymorphism

Intrathecal morphine provides superior analgesia and minimizes side effects with ~1/300th of the oral dose necessary to achieve this effect. The conversion ratios from oral route to intrathecal route vary greatly among individuals, and this may be related with polymorphisms of the ATP-binding cassette B1 (ABCB1)/multiple drug resistance 1 (MDR1) gene encoding the transporter P-glycoprotein in the blood–brain barrier. In the case presented herein, a patient with cancer pain for over 3 months was treated with oxycodone hydrochloride prolonged-release tablets (Oxycontin) and morphine hydrochloride tablets for breakthrough pain. The patient was admitted due to intolerable adverse effects of Oxycontin. During this admission, he was implanted with an intrathecal morphine pump which can deliver morphine into the cerebrospinal fluid. To our surprise, intrathecal morphine at a dose of ~1/540th of oral morphine equivalent dose produced complete analgesia. Our finding revealed homogenous CC at position 3435 (C3435T) in the ABCB1/MDR1 gene in this patient, which encodes P-glycoprotein with good efflux pump functionality. As intrathecal morphine bypasses the blood–brain barrier that oral medications have to pass through, the good pump functionality may have contributed to the super analgesia of intrathecal morphine in this case. Genetic analysis of ABCB1/MDR1 gene polymorphisms can be useful for personalized pain management in patients with intrathecal morphine pump.

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

Background

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

Methods

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

Results

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

Conclusions

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

Long-term morphine delivery via slow release morphine pellets or osmotic pumps: Plasma concentration, analgesia, and naloxone-precipitated withdrawal

AIMS

Slow-release morphine sulfate pellets and osmotic pumps are common routes of chronic morphine delivery in mouse models, but direct comparisons of these drug delivery systems are lacking. In this study, we assessed the efficacy of slow-release pellets versus osmotic pumps in delivering morphine to adult mice.

MAIN METHODS

Male C57BL/6NCr mice (8weeksold) were implanted subcutaneously with slow-release pellets (25mg morphine sulfate) or osmotic pumps (64mg/mL, 1.0μL/h). Plasma morphine concentrations were quantified via LC-MS/MS, analgesic efficacy was determined by tail flick assay, and dependence was assessed with naloxone-precipitated withdrawal behaviors (jumping) and physiological effects (excretion, weight loss).

KEY FINDINGS

Morphine pellets delivered significantly higher plasma drug concentrations compared to osmotic pumps, which were limited by the solubility of the morphine sulfate and pump volume/flow rate. Within 96h post-implantation, plasma morphine concentrations were indistinguishable in pellet vs. pump-treated samples. While osmotic pump did not have an antinociceptive effect in the tail flick assay, pumps and pellets induced comparable dependence symptoms (naloxone-precipitated jumping behavior) from 24-72h post-implantation.

SIGNIFICANCE

In this study, we compared slow-release morphine pellets to osmotic minipumps for morphine delivery in mice. We found that osmotic pumps and subcutaneous morphine sulfate pellets yielded significantly different pharmacokinetics over a 7-day period, and as a result significantly different antinociceptive efficacy. Nonetheless, both delivery methods induced dependence as measured by naloxone-precipitated withdrawal.

Intrathecal morphine verse femoral nerve block for pain control in total knee arthroplasty: A meta-analysis from randomized control trials

OBJECTIVE

Total knee arthroplasty (TKA) is usually associated with postoperative pain. The objective of this systematic review and meta-analysis was to evaluate the effectiveness and safety of femoral nerve block compared with intrathecal morphine for pain management after TKA.

METHODS

Potentially relevant literature was identified from electronic databases including Medline, PubMed, Embase, ScienceDirect and the Cochrane Library. Gray academic studies were also identified from the reference of included literature. There was no language restriction. Pooling of data was carried out using Stata 11.0.

RESULTS

Four randomized controlled trials (RCTs) involving 185 patients met the inclusion criteria. The meta-analysis indicated that there were no significant differences in terms of Visual Analog Scale (VAS) score at 6 h (standard mean difference (SMD) = -0.09, 95% CI: -1.62 to 1.43, P = 0.903), 12 h (weighted mean difference (WMD) = 1.84, 95% CI: -8.01 to 11.69, P = 0.714) or 24 h (WMD = 1.56, 95% CI: -14.31 to 17.42, P = 0.8474). No significant difference were found regarding morphine consumption at 6 h (WMD = -0.84, 95% CI: -2.52 to 0.85, P = 0.332), 12 h (WMD = 0.031, 95% CI: -3.304 to 0.3366, P = 0.985), 24 h (WMD = 0.21, 95% CI: -7.32 to 7.75, P = 0.956) or incidence of postoperative vomit and nausea (risk difference (RD) = -0.01, 95% CI: -0.15 to 0.12, P = 0.847). There was a significant difference between the groups in terms of the risk of itching postoperatively (RD = 0.41, 95% CI: 0.29 to 0.54, P < 0.001).

CONCLUSIONS

Femoral nerve block provides equal postoperative pain control compared with intrathecal morphine following total knee arthroplasty, although there were fewer side effects in the FNB groups. In contrast, FNB was performed with an additional procedure and required a special apparatus. Both methods are effective at pain control following TKA.