Efficacy of Simultaneous Usage of Spinal Cord Stimulation and Intrathecal Therapy for Nonmalignant Chronic Neuropathic Pain

Multidisciplinary Approaches: Cingulotomy in an Adult With Refractory Neuropathic Cancer-Related Pain

Background: Oral medications, intravenous medications, and invasive interventions are effective means of neuropathic pain control. In patients with pain refractory to more conventional approaches, cingulum bundle ablation is an alternative treatment modality not routinely considered by providers. Case Description: A 42-year-old woman with history of cervical cancer in remission presented with intractable left lower extremity pain. Workup revealed radiation-induced left iliopsoas osteosarcoma complicated by deep venous occlusion and thrombosis. Her pain remained intractable to pharmacologic therapies and more invasive pain control interventions. A multidisciplinary decision was made to pursue bilateral subcortical cingulum bundle radiofrequency ablation. After a technically successful surgery, the patient exhibited improved pain control as evidenced by a decline in her numerical rating scale of pain and analgesic medication requirements. Conclusion: Cancer-related neuropathic pain often requires treatment with multiple modalities involving multidisciplinary teams. In select refractory cases, cingulum bundle ablation may be an effective alternative treatment modality.

Stimulation holiday rescues analgesia after habituation and loss of efficacy from 10-kilohertz dorsal column spinal cord stimulation

INTRODUCTION

Habituation and loss of efficacy from spinal cord stimulation are commonly reported. This retrospective analysis investigated rescue of analgesia from spinal cord stimulation failure after implementing a strategy called a stimulation holiday, during which spinal cord stimulation is interrupted for a defined period and subsequently restarted.

METHODS

A 6-year review (June 1, 2016-May 13, 2022) from a tertiary care center was conducted on patients who underwent 10 kHz frequency dorsal column spinal cord stimulation for ≥3 months, experienced loss of efficacy (≤30% pain relief or patient self-report of lack of meaningful pain relief), subsequently underwent a stimulation holiday, and then restarted spinal cord stimulation. The primary outcome was comparison of pain relief and responder rate (≥50% relief in pain intensity) before and after stimulation holiday.

RESULTS

Of 212 patients, 40 (18.9%) experienced loss of efficacy at a mean follow-up period of 452.7±326.4 days after stimulator implantation and underwent stimulation holiday. Pain relief was significantly higher 1 month after stimulation holiday (39.4%±28.6%) compared with before stimulation holiday (8.7%±13.0%; mean difference 30.6%, 95% CI 21.9% to 39.3%, paired t-test p<0.001). A significantly higher responder rate (≥50% relief in pain intensity) was identified after stimulation holiday (57.5%) compared with before stimulation holiday (0%; Fisher's exact test p<0.001). Associations of superior pain relief and responder rate remained significant at 3 and 6 months after stimulation holiday.

DISCUSSION

Patients who experience loss of efficacy from spinal cord stimulation habituation could attempt a stimulation holiday rather than abandon therapy. Rescue of analgesia may be achieved after implementing a stimulation holiday and restarting spinal cord stimulation.

Targeted Drug Delivery for Chronic Nonmalignant Pain: Longitudinal Data From the Product Surveillance Registry

OBJECTIVES

To assist in assessment of therapy risks and benefits of targeted drug delivery (TDD) for chronic nonmalignant pain using registry data on product performance, adverse events, and elective device replacement.

MATERIALS AND METHODS

The Product Surveillance Registry (PSR) (NCT01524276) is an ongoing prospective, long-term, multicenter registry enrolling consented patients implanted with an intrathecal drug delivery system. Patients are followed prospectively with participating investigators providing pump and catheter performance data for events related to the device, procedure, and therapy. Event descriptions include patient symptoms and outcomes.

RESULTS

Registry data from the 4646 patients (59.7% female) treated with TDD for chronic, nonmalignant pain at 59 registry sites between August 2003 and October 2019, with over 17,000 patient-years (4646 patients with 44 months average follow-up), were analyzed. Registry discontinuation was largely (46.2% of discontinued patients) due to study site closure and patient death; exit due to an adverse or device event was limited to 10.2%.

CONCLUSIONS

Treating chronic pain with escalating doses of strong systemic opioids often leads to inconsistent pain control, impaired function, untenable side effects, and reduced quality of life and this practice has contributed to the current opioid crisis in the United States. TDD has been an available therapy for these patients for greater than 30 years, and data from this real-world registry offer supporting evidence to the long-term safety of this therapy as an alternative to systemic opioids, as well as insights into patient acceptance and satisfaction.

Treatment Strategies for Generator Pocket Pain

OBJECTIVE

Generator site pain is a relatively common phenomenon in patients undergoing spinal cord stimulation (SCS) that complicates management and effective pain relief. This pain may be managed conservatively, with repositioning of the battery and, in some cases, with explant. Here we explore our experience with management of generator site pain ("pocket pain") in a large single-center study.

METHODS

All SCS permanent implants and implantable pulse generator (IPG) placements over 9 years were reviewed. Of 785 cases, we identified 43 patients with pocket pain (5.5%). Demographics and treatments of the pocket pain cohort were analyzed.

RESULTS

The mean age (± SEM) of the pocket pain cohort was 46.86 ± 1.06, and there were 10/33 males/females. Females were overrepresented in pocket pain cohort (76.7%) when compared with the total SCS cohort (59.0%) (X2 = 5.93, P = 0.015). Diagnosis included failed back surgery syndrome (51.2%), complex regional pain syndrome (23.3%), and chronic neuropathic pain (25.5%). No patients improved with conservative therapy. All patients either went on to revision (n = 23) or explant (n = 20). Time from initial surgery to development of pocket pain was 7.5 months (range: 0.3-88) and from pocket pain to revision surgery was 4.5 months (range: 0.4-26). In addition, significantly more pocket pain patients (65.1%) had workers' compensation (WC) insurance compared with patients without pocket pain (24.9%) (X2 = 33.3, P < 0.001).

CONCLUSION

In our institutional experience, pocket pain was inadequately managed with conservative treatments. Being female and having SCS filed under WC increased risk of pocket pain. Future work will explore the nuances in device placement based on body shape and manual activity responsibilities.

Stem Cell Neurodevelopmental Solutions for Restorative Treatments of the Human Trunk and Spine

The ability to reliably repair spinal cord injuries (SCI) will be one of the greatest human achievements realized in regenerative medicine. Until recently, the cellular path to this goal has been challenging. However, as detailed developmental principles are revealed in mouse and human models, their application in the stem cell community brings trunk and spine embryology into efforts to advance human regenerative medicine. New models of posterior embryo development identify neuromesodermal progenitors (NMPs) as a major bifurcation point in generating the spinal cord and somites and is leading to production of cell types with the full range of axial identities critical for repair of trunk and spine disorders. This is coupled with organoid technologies including assembloids, circuitoids, and gastruloids. We describe a paradigm for applying developmental principles towards the goal of cell-based restorative therapies to enable reproducible and effective near-term clinical interventions.

A safety review of approved intrathecal analgesics for chronic pain management

Introduction: Intrathecal (IT) drug therapy is an effective treatment option for patients with chronic pain of malignant or nonmalignant origin, with an established safety profile and fewer adverse effects compared to oral or parenteral pain medications. Morphine (a μ-opioid receptor agonist) and ziconotide (a non-opioid calcium channel antagonist) are the only IT agents approved by the U.S. Food and Drug Administration for the treatment of chronic pain. Although both are considered first-line IT therapies, each drug has unique properties and considerations.Areas Covered: This review will evaluate the pivotal trials that established the use of morphine and ziconotide as first-line IT therapy for patients with chronic pain, as well as safety and efficacy data generated from various retrospective and prospective studies.Expert Opinion: Morphine and ziconotide are effective IT therapies for patients with chronic malignant or nonmalignant pain that is refractory to other interventions. IT ziconotide is recommended as a first-line therapy due to its efficacy and avoidance of many adverse effects commonly associated with opioids. The use of IT morphine is also considered first-line; however, the risks of respiratory depression, withdrawal with drug discontinuation or pump malfunction, and the development of tolerance require careful patient selection and management.

Neuromodulation for Medically Refractory Neuropathic Pain: Spinal Cord Stimulation, Deep Brain Stimulation, Motor Cortex Stimulation, and Posterior Insula Stimulation

BACKGROUND

The treatment of neuropathic pain (NP) continues to be controversial as well as an economic health issue and a challenge to health care. Neurosurgery can offer different methods of neuromodulation that may improve patients' condition, including deep brain stimulation (DBS), motor cortex stimulation (MCS), spinal cord stimulation (SCS), and posterior insula stimulation (PIS). There is no consensus of opinion as to the final effects of these procedures, which stimulation parameters to select, the correct timing, or how to select the patients who will best benefit from these procedures.

OBJECTIVE

To review the evidence available regarding these 4 procedures and the management of NP.

METHODS

We conducted a PubMed, Embase, and Cochrane Library database search from 1990 to 2020. The strategy of the search concentrated on the following keywords: "neuropathic pain," "chronic pain," "deep brain stimulation," "motor cortex stimulation," "spinal cord stimulation," "insula stimulation," and "neuromodulation." Studies that provided data regarding the immediate and long-term effectiveness of the procedure, anatomic stimulation target, percentage of pain control, and cause of the NP were included.

RESULTS

The most frequent causes of NP were phantom limb pain and central poststroke pain in the MCS group; central poststroke pain, phantom limb pain, and spinal cord injury (SCI) in the DBS group; and complex regional pain syndrome and failed back surgery syndrome in the SCS group. Pain improvement varied between 35% and 80% in the MCS group and 50% and 60% in the DBS group. In the SCS group, successful rates varied between 38% and 89%.

CONCLUSIONS

This systematic review highlights the literature supporting SCS, DBS, MCS, and PIS methods for the treatment of NP. We found consistent evidence supporting MCS, DBS, and SCS as possible treatments for NP; however, we were not able to define which procedure should be indicated for each cause. Furthermore, we did not find enough evidence to justify the routine use of PIS. We conclude that unanswered points need to be discussed in this controversial field and emphasize that new research must be developed to treat patients with NP, to improve their quality of life.