Intrathecal pain management: a team-based approach

[Perceived utility of the inclusion of physician assistants in the surgical process quality and continuing education in Germany : Results of an interprofessional online survey]

BACKGROUND

Compared to Anglo-American countries, physician assistants (PA) remain an underrepresented professional group within the German healthcare system. In the surgical disciplines, PAs may relieve the administrative burden of doctors by taking on delegable routine tasks, thus creating time and resources for advanced surgical training.

OBJECTIVE

According to interprofessional experts, can the use of PA lead to an optimization of surgical training and a gain in time for surgical qualification in Germany?

MATERIAL AND METHODS

After searching for systematic reviews of the current state of knowledge, an online survey was initiated among surgeons and PAs via social networks to determine current and desired clinical areas of activity for PAs in surgery and their future influence on specialist training in Germany.

RESULTS

A total of nine systematic reviews were identified, suggesting a beneficial impact of PAs on length of stay, direct costs, and treatment outcomes in surgical scenarios. The online survey included 234 surgeons and 114 PAs. Hospitals with ≥ 90 surgical beds employed PAs far more frequently (65%) than smaller institutions (40%). Although both professional groups are generally highly satisfied with the integration of PAs into clinical workflows, there are gradually different opinions about the preferred spectrum of tasks and duties.

DISCUSSION

PAs would like to have greater responsibility in ordering and interpreting diagnostic tests, communicating with patients, and working in the operating theater. Surgeons are concerned that PAs could replace surgical interns and residents. PAs may enrich healthcare in Germany on various levels and can also improve surgical training. The voice and needs of all professional groups must be considered and respected during the upcoming health system reform.

A comprehensive review on ziconotide

Managing severe chronic pain is a challenging task, given the limited effectiveness of available pharmacological and non-pharmacological treatments. This issue continues to be a significant public health concern, requiring a substantial therapeutic response. Ziconotide, a synthetic peptide initially isolated from Conus magus in 1982 and approved by the US Food and Drug Administration and the European Medicines Agency in 2004, is the first-line intrathecal method for individuals experiencing severe chronic pain refractory to other therapeutic measures. Ziconotide produces powerful analgesia by blocking N-type calcium channels in the spinal cord, which inhibits the release of pain-relevant neurotransmitters from the central terminals of primary afferent neurons. However, despite possessing many favorable qualities, including the absence of tolerance development, respiratory depression, and withdrawal symptoms (largely due to the absence of a G-protein mediation mechanism), ziconotide's application is limited due to factors such as intrathecal administration and a narrow therapeutic window resulting from significant dose-related undesired effects of the central nervous system. This review aims to provide a comprehensive and clinically relevant summary of the literatures concerning the pharmacokinetics and metabolism of intrathecal ziconotide. It will also describe strategies intended to enhance clinical efficacy while reducing the incidence of side effects. Additionally, the review will explore the current efforts to refine the structure of ziconotide for better clinical outcomes. Lastly, it will prospect potential developments in the new class of selective N-type voltage-sensitive calcium-channel blockers.

Covalently Binding Adenosine A3 Receptor Agonist ICBM Irreversibly Reduces Voltage-Gated Ca2+ Currents in Dorsal Root Ganglion Neurons

Interest has been focused in recent years on the analgesic effects exerted by adenosine and its receptors, A1, A2A, A2B, and A3 adenosine receptor (AR) subtypes, in different in vivo models of chronic pain. In particular, it was demonstrated that selective A3AR agonists reduced pro-nociceptive N-type Ca2+ channels in dorsal root ganglion (DRG) neurons isolated from rats and, by this mechanism, inhibit post inflammatory visceral hypersensitivity. In the present study, we investigate the effect of a previously reported irreversibly binding A3AR agonist, ICBM, on Ca2+ currents (ICa) in rat DRG neurons. Present data demonstrate that ICBM, an isothiocyanate derivative designed for covalent binding to the receptor, concentration-dependently inhibits ICa. This effect is irreversible, since it persists after drug removal, differently from the prototypical A3AR agonist, Cl-IB-MECA. ICBM pre-exposure inhibits the effect of a subsequent Cl-IB-MECA application. Thus, covalent A3AR agonists such as ICBM may represent an innovative, beneficial, and longer-lasting strategy to achieve efficacious chronic pain control versus commonly used, reversible, A3AR agonists. However, the possible limitations of this drug and other covalent drugs may be, for example, a characteristic adverse effect profile, suggesting that more pre-clinical studies are needed.

Cancer-Related Pain Management in Suitable Intrathecal Therapy Candidates: A Spanish Multidisciplinary Expert Consensus

A consensus is needed among healthcare professionals involved in easing oncological pain in patients who are suitable candidates for intrathecal therapy. A Delphi consultation was conducted, guided by a multidisciplinary scientific committee. The 18-item study questionnaire was designed based on a literature review together with a discussion group. The first-round questionnaire assessed experts' opinion of the current general practice, as well as their recommendation and treatment feasibility in the near future (2-3-year period) using a 9-point Likert scale. Items for which consensus was not achieved were included in a second round. Consensus was defined as ≥75% agreement (1-3 or 7-9). A total of 67 panelists (response rate: 63.2%) and 62 (92.5%) answered the first and second Delphi rounds, respectively. The participants were healthcare professionals from multiple medical disciplines who had an average of 17.6 (7.8) years of professional experience. A consensus was achieved on the recommendations (100%). The actions considered feasible to implement in the short term included effective multidisciplinary coordination, improvement in communication among the parties, and an assessment of patient satisfaction. Efforts should focus on overcoming the barriers identified, eventually leading to the provision of more comprehensive care and consideration of the patient's perspective.

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.

An Advanced Practice Provider Guide to Peripheral Nerve Stimulation

Objective

To describe the team approach of an interventional pain management practice, with particular emphasis on advanced practice providers (APPs), in the selection, education, care, and management of peripheral nerve stimulation (PNS) patients.

Materials and Methods

We devised an APP guide to PNS based on an in-depth search of multiple databases for studies on neuromodulation, pain management, and APPs.

Results

Of 65 articles captured in the search strategy, three articles were pertinent to the topic of APP involvement in neuromodulation. More specifically, only one of the three publications on neuromodulation discussed APP involvement in PNS. This single publication was from 1995 and focused on electrical stimulation of the trigeminal ganglion using a permanent percutaneously placed electrode.

Conclusion

PNS is growing in clinical indication and use for both acute and chronic pain conditions. With the increasing need for APPs in both general and specialty medicine, it is imperative that APPs are well educated on PNS. Here, we have outlined ways in which APPs can optimize the care of PNS patients and how the skillset of the APP in a PNS practice can potentially improve patient outcomes.

Intrathecal Drug Delivery Systems Survey: Trends in Utilization in Pain Practice

Background

The use of intrathecal drug delivery for chronic and cancer pain medicine has been established for decades. However, optimization and utilization of this technique still lag behind other modalities for pain control. Some of this may be due to variability of surgical technique, medication usage and education. It is currently unclear on whether or not practitioners follow available algorithms for the use of intrathecal drug delivery systems.

Methods

A survey developed by the American Society of Pain and Neuroscience (ASPN) was sent to its members via email using the cloud-based SurveyMonkey. After 30 days of being available, 159 different providers responded to the survey that consisted of 31 various multiple choice and free response questions. Each question was not required and the number of responses to each varied from 128 to 159.

Results

Approximately 9% of those who successfully received and opened the email containing the survey responded, likely due to a small number of providers working with intrathecal drug delivery systems. Eighty-six of respondents practice medicine in the United States, and 87% of the respondents were attending physicians. A majority of respondents, approximately 74%, were board certified in pain medicine with 69% of respondents being train in anesthesiology. The first and second most used medications for intrathecal pump trial were morphine and fentanyl, respectively. Most respondents, approximately 96%, provide pre-operative/intra-operative antibiotics. The most common first-choice medication for implanted intrathecal pumps was also morphine with the most common implanted location being the abdomen.

Conclusion

Interestingly, there is currently fairly substantial variation in the way providers utilize intrathecal pump delivery for both chronic and cancer pain. There is variation from the training background of the providers providing care, to the pre-implantation trial medications, to where the pump is implanted for each patient, to if the patient has the option to give themselves boluses once implanted. Further research is needed to elucidate current and best practices for intrathecal drug delivery system trials, implantations, and utilization.

Perioperative Opioid Consumption and Clinical Outcomes in Surgical Patients With a Pre-existing Opioid-Based Intrathecal Drug Delivery System

BACKGROUND

Intrathecal drug delivery systems (IDDS) have been utilized for over 3 decades for management of chronic pain and spasticity. Patients with IDDS may present for surgical procedures unrelated to the IDDS device, although data are limited regarding perioperative outcomes.

METHODS

This is a historical matched cohort study conducted between January 1, 2007 and December 31, 2016 of patients with an opioid-based IDDS versus matched control patients undergoing surgery excluding interventional pain procedures. Patients in the IDDS group were matched with up to 2 patients without an IDDS. Multivariable regression analyses were utilized to assess differences in the primary outcome of cumulative perioperative opioid consumption (ie, intraoperative and postanesthesia care unit [PACU] opioid consumption), and opioid consumption during the first 24 and 72 postoperative hours. Postoperative clinical outcomes were also assessed including escalating oxygen requirements, naloxone administration, pain-sedation mismatch, and perioperative pain service consultation.

RESULTS

A total of 321 surgeries were included, 112 with IDDS and 209 controls, with median (interquartile range [IQR]) age of 57 (49-64) years. Compared to matched controls, patients with an IDDS had greater perioperative opioid consumption (median [IQR] oral morphine milligram equivalents [OME] of 110 [60-163] vs 93 [IQR, 53-142]; adjusted multiplicative increase 1.28 [95% confidence interval {CI}, 1.03-1.59]; P = .026). IDDS patients also had greater opioid consumption in the first 24 and 72 postoperative hours (multiplicative increases of 2.23 [95% CI, 1.36-3.63], P = .001, and 2.46 [95% CI, 1.41-4.32], P = .002, respectively). There were no significant differences in postoperative oxygen requirements, naloxone administration, or pain-sedation mismatch. Inpatient pain medicine consultation was more frequent in IDDS patients compared to controls (51.8% vs 6.2%; P < .001).

CONCLUSIONS

Patients with opioid-based IDDS received more perioperative opioids and were more likely to receive postoperative pain service consultation compared to matched controls. There were no significant differences in clinical safety outcomes, suggesting tolerance for higher opioid doses. Further research is warranted to optimize perioperative outcomes in those with IDDS.

A Review and Analysis of Managing Commonly Seen Implanted Devices for Patients Undergoing Radiation Therapy

Purpose

This review article aims to consolidate information regarding existing and emerging implanted devices used in patients undergoing radiation therapy and to categorize levels of attention needed for each device, including which devices require monitoring throughout treatment.

Methods and Materials

Based on the collective information from scholar searches, manufacturers' technical reports, and institutional experiences in the past years, commonly present devices in patients with cancer are compiled. This work summarizes cardiac pacemaker, implanted cardiac defibrillator, hepatic pump, intrathecal pain pump, neurostimulator, shunt, loop recorder, and mediport. Three different classifications of implanted devices can be made based on the potential effect of radiation: life-dependent, nonlife-dependent but with adverse effects if overdosed, and devices without electronic circuits. Implanted devices that contain electronic circuits that would be life-dependent or have adverse effects if overdosed, include cardiac pacemakers, implanted cardiac defibrillators, programmable hepatic pumps, pain pumps, neurostimulators, and loop recorders.

Results

Dose exposure to these devices need to be calculated or measured in vivo, especially for cardiac implanted devices, and they should be minimized to assure continued healthy functioning. Treatment planning techniques should be chosen to reduce entry, exit and internal scatter dose. Lower energy photon beams should be used to decrease potential neutron contamination. Implanted devices without electronic circuits are less of a concern. If a patient is life-dependent on the implanted device, it is not recommended to treat the patient with proton therapy.

Conclusions

This study reviewed the management of patients with commonly seen implanted devices and summarized a workflow for identifying and planning when a patient has implanted devices. Classifications of implanted devices could help clinicians make proper decisions in regard to patients with specific implanted devices. Lastly, the management of such devices in the era of the pandemic is also discussed in this review article.

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.

Role of transforaminal epidural injections or selective nerve root blocks in the management of lumbar radicular syndrome - A narrative, evidence-based review

OBJECTIVE

Lumbar radicular Syndrome (LRS) is a common spinal pathology and is attributed to complex interplay of mechanical, inflammatory and immunological processes. Epidural injection of steroids has a significant therapeutic role in mitigating the inflammatory component of LRS. Trans-foraminal approach under image guidance enables a targeted drug delivery. The current narrative review discusses the various aspects related to lumbar trans-foraminal epidural injection of steroid (LTFIS).

METHODS

An elaborate search on PubMed, Google and Medline databases was made using keywords "lumbar selective nerve root block", "lumbar trans-foraminal epidural steroid injection", "selective nerve root block in lumbar disc prolapse", "trans-foraminal epidural steroid injection in lumbar prolapse", "selective nerve root block in lumbar radiculopathy", and "trans-foraminal epidural steroid injection in lumbar radiculopathy" The articles were selected based on specific inclusion criteria.

RESULTS

Our search identified 539 articles. All articles discussing alternate procedures, LTFIS in other pathologies, diagnostic roles of LTFIS, not pertaining to concerned questions, in non-English language and duplicate articles were excluded. Review articles, randomised controlled trials or level 1 studies were given preference. Overall, 108 articles were included. Being a focussed narrative review, further screening [Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) or Methodological Index for non-randomized studies (MINORS) criteria] was not performed to select articles. Based on the evidence, LTFIS is an effective and useful treatment modality. It is offered to patients with lumbar disc herniation (LDH) presenting with persistent, unilateral, radiculopathy after a course of conservative measures for around 6 weeks' duration. It has been reported to yield better results than caudal or inter-laminar epidural injections. The anti-inflammatory and nociceptive signal stabilization actions of steroids, as well as mechanical effects of washout of inflammatory mediators and neural lysis contribute to its efficacy. The three different approaches include sub-pedicular, retro-neural and retro-discal. The procedure is performed under image guidance using a water-soluble contrast under fluoroscopy. The four described radiculogram patterns include "arm", "arrow", "linear" and "splash". Computerised tomography, ultrasonography and magnetic resonance imaging are other modalities, which may be helpful in performing LTFIS. The use of particulate versus non-particulate steroids is controversial.

CONCLUSION

The overall success rate of SNRB is reported to be 76-88%. The majority of benefits are observed during immediate and early post-injection period. Clinical factors including duration and severity of symptoms, and radiological factors like presence of osteophytes, location, size and type of disc prolapse influence outcomes. The radiculogram "splash" pattern is associated with poor outcomes.

Adenosine A3 receptor activation inhibits pronociceptive N-type Ca2+ currents and cell excitability in dorsal root ganglion neurons

Recently, studies have focused on the antihyperalgesic activity of the A3 adenosine receptor (A3AR) in several chronic pain models, but the cellular and molecular basis of this effect is still unknown. Here, we investigated the expression and functional effects of A3AR on the excitability of small- to medium-sized, capsaicin-sensitive, dorsal root ganglion (DRG) neurons isolated from 3- to 4-week-old rats. Real-time quantitative polymerase chain reaction experiments and immunofluorescence analysis revealed A3AR expression in DRG neurons. Patch-clamp experiments demonstrated that 2 distinct A3AR agonists, Cl-IB-MECA and the highly selective MRS5980, inhibited Ca-activated K (KCa) currents evoked by a voltage-ramp protocol. This effect was dependent on a reduction in Ca influx via N-type voltage-dependent Ca channels, as Cl-IB-MECA-induced inhibition was sensitive to the N-type blocker PD173212 but not to the L-type blocker, lacidipine. The endogenous agonist adenosine also reduced N-type Ca currents, and its effect was inhibited by 56% in the presence of A3AR antagonist MRS1523, demonstrating that the majority of adenosine's effect is mediated by this receptor subtype. Current-clamp recordings demonstrated that neuronal firing of rat DRG neurons was also significantly reduced by A3AR activation in a MRS1523-sensitive but PD173212-insensitive manner. Intracellular Ca measurements confirmed the inhibitory role of A3AR on DRG neuronal firing. We conclude that pain-relieving effects observed on A3AR activation could be mediated through N-type Ca channel block and action potential inhibition as independent mechanisms in isolated rat DRG neurons. These findings support A3AR-based therapy as a viable approach to alleviate pain in different pathologies.