Technological innovation in spinal cord stimulation: use of a newly developed delivery device for introduction of spinal cord stimulation leads

The Evolution of Surgical Technique in Spinal Cord Stimulation: A Scoping Review

Since the advent of spinal cord stimulation (SCS), its operative technique has consistently advanced. We performed a scoping review of the literature regarding SCS operative techniques to highlight key advancements. To review, summarize, and highlight key changes in SCS implantation techniques since their inception. The authors performed a MEDLINE search inclusive of articles from 1967 to June 2023 including human and modeling studies written in English examining the role of trialing, intraoperative neuromonitoring, and surgical adaptations. Using the Rayyan platform, two reviewers performed a blinded title screen. Of the 960 articles, 197 were included in the title screen, 107 were included in the abstract review, and ultimately 69 articles met inclusion criteria. We examined the utility of trialing and found that historical controls showed significant efficacy, whereas recent results are more equivocal. We discuss the significant improvement in outcomes with intraoperative neuromonitoring for asleep SCS placement. We highlight technique improvements that led to significant reductions in infection, lead migration, and inadequate pain relief. Physicians implanting SCS systems for chronic pain management must continually refine their surgical techniques to keep up with this rapidly evolving therapy. In addition, through collaborative efforts of neuromodulators and industry, SCS is safer and more effective for patients suffering from chronic pain.

Epidural Spinal Cord Stimulation for Spinal Cord Injury in Humans: A Systematic Review

(1) Background: Spinal cord injury (SCI) represents a major health challenge, often leading to significant and permanent sensorimotor and autonomic dysfunctions. This study reviews the evolving role of epidural spinal cord stimulation (eSCS) in treating chronic SCI, focusing on its efficacy and safety. The objective was to analyze how eSCS contributes to the recovery of neurological functions in SCI patients. (2) Methods: We utilized the PRISMA guidelines and performed a comprehensive search across MEDLINE/PubMed, Embase, Web of Science, and IEEE Xplore databases up until September 2023. We identified studies relevant to eSCS in SCI and extracted assessments of locomotor, cardiovascular, pulmonary, and genitourinary functions. (3) Results: A total of 64 studies encompassing 306 patients were identified. Studies investigated various stimulation devices, parameters, and rehabilitation methods. Results indicated significant improvements in motor function: 44% of patients achieved assisted or independent stepping or standing; 87% showed enhanced muscle activity; 65% experienced faster walking speeds; and 80% improved in overground walking. Additionally, eSCS led to better autonomic function, evidenced by improvements in bladder and sexual functions, airway pressures, and bowel movements. Notable adverse effects included device migration, infections, and post-implant autonomic dysreflexia, although these were infrequent. (4) Conclusion: Epidural spinal cord stimulation is emerging as an effective and generally safe treatment for chronic SCI, particularly when combined with intensive physical rehabilitation. Future research on standardized stimulation parameters and well-defined therapy regimens will optimize benefits for specific patient populations.

Postoperative Infections Associated With Prolonged Spinal Cord Stimulation Trial Duration (PROMISE RCT)

Introduction

In the PROMISE study, a multinational randomized controlled trial (RCT) of the effectiveness of spinal cord stimulation (SCS) with multicolumn surgical leads as a treatment of low back pain, clinicians followed their usual practice. An early, unplanned safety analysis revealed that the infection rate in Belgium (5/23), where trial duration was a median 21.5 days, was significantly higher than the 1/64 rate observed in the other study countries (median 5.8 days, p < 0.01). This report reviews infections observed in the PROMISE study after study completion.

Materials and Methods

For all infections related to SCS, we used descriptive statistics and tests of independent variables to analyze potentially contributing factors (age, sex, coexisting medical conditions, tobacco use, lead type, and trial duration) between subjects with infections versus those without. Cumulative incidence curves were created using the Kaplan–Meier method and compared between the two strata using a log‐rank test.

Results

Among nine (5.2%) infections in 174 subjects trialed, the only significant contributing factor to infection was trial duration: median 21 days (range 3–56) for those with infection vs. six days (1–41) for those without (p = 0.001; Wilcoxon rank‐sum test). The cumulative incidence of infection for subjects trialed >10 days was 24.1% vs. 1.4% for subjects trialed ≤10 days (p < 0.001). After the protocol was amended to limit trial duration to 10 days, 14 infection‐free trials were performed in Belgium.

Conclusions

Although not part of the preplanned analysis, our observation supports the hypothesis of a cause‐effect relationship between trial duration and the risk of infection and the conclusion that prolonged SCS trials should be avoided.

Redefining Spinal Cord Stimulation "Trials": A Randomized Controlled Trial Using Single-Stage Wireless Permanent Implantable Devices

BACKGROUND

"Traditional" spinal cord stimulation (SCS) trials with percutaneous electrodes externalized to a pulse generator (PG) are typically limited in duration due to risk of infection. Newer miniaturized wireless SCS technology eliminates the percutaneous extension (as well as PGs implanted for chronic use), thus facilitating a single-stage implantation after which the device can remain indefinitely.

OBJECTIVE

To evaluate fully implanted wireless SCS devices during a 30-day screening trial in subjects with chronic low back pain and leg pain and a history of lumbosacral spine surgery.

METHODS

In a randomized controlled trial of single-stage wireless SCS using a wireless percutaneous system, 99 subjects received either 10 kHz high frequency stimulation (HFS) or lower frequency stimulation (LFS) below 1500 Hz (Bolash R, Creamer M, Rauck R, et al. Wireless high frequency spinal cord stimulation (10 kHz) compared to multi-waveform low frequency spinal cord stimulation in the management of chronic pain in failed back surgery syndrome subjects: preliminary results of a multicenter, prospective, randomized controlled study. Pain Med 2019, https://doi.org/10.1093/pm/pnz019). In this report, we assess the 30-day trial success rate (≥50% pain relief from baseline) and complications.

RESULTS

The overall trial success rate was 88% (87/99): 92% (46/50) for HFS and 84% (41/49) for LFS (NS). The trial success rate in the 64 subjects with predominant low back pain was 92% (59/64) vs. 80% (28/35) in those with leg pain ≥ low back pain (NS). During the screening trial, one infection occurred (1%) and one subject withdrew and was explanted (1%). Electrode migrations were seen on routine follow-up x-rays in 10 cases (10%).

CONCLUSION

Using wireless SCS devices that allow for an extended trial period and evaluation of various waveforms, we observed a high rate trial success rate with both HFS and LFS waveforms, with minimal incidence of infection. Long-term follow-up will address the cost-effectiveness and morbidity associated with this technology, which facilitates single-stage treatment.

A new minimally invasive technique for lead revision of perc-paddle leads

To report on a less-invasive technique for replacing a broken lead in a spinal cord stimulation (SCS) device that makes use of St. Jude Medical's "Epiducer" device. A 53-year-old woman suffered a loss of stimulation on her internal pulse generator (IPG), which was found to have a broken lead. The broken lead was withdrawn using the Epiducer device with minimal invasiveness and without pain. A new lead was put in place, and successful stimulation using the IPG resumed. Follow-up 3 weeks later showed a well-functioning SCS system. An Epiducer can be used to revise the SCS system in a minimal invasive way without a new puncture. Follow-up study of this technique as well as others for revising an SCS system should be encouraged and used in comparison study.

The Factors Affecting the Difficulty of Percutaneous Cylindrical Electrode Placement for Spinal Cord Stimulation

OBJECTIVE

Optimal placement of electrodes is important for spinal cord stimulation. Factors affecting the difficulty of percutaneous electrode placement are not well known. In this study, we retrospectively evaluated the factors affecting the difficulty of percutaneous electrode placement.

METHODS

We performed a retrospective analysis of 90 consecutive procedures of percutaneous cylindrical electrode implantation at the first author's institution. Age, sex, smoking state, body mass index, the duration of time from the beginning of pain syndrome to operation, diagnosis, the number of previous electrode placements, the previous electrode implantation period, the presence of axial low back pain, the electrode tip level, the pattern of electrode placement, and the reason for reimplantation were selected as factors associated with the success of electrode placement or the operation time of electrode placement.

RESULTS

The number of previous electrode placements and the electrode tip level were independently associated with the operation time of electrode placement. According to both univariable and multivariable regression analyses, 1 previous electrode placement lengthened the operation time by approximately 15 minutes. No factors were significantly associated with the success of electrode placement. The more frequently that previous electrode placement was performed, the more difficult electrode placement tended to be. However, electrode reimplantation can be successful given extra time.

CONCLUSIONS

This is the first study to evaluate factors affecting the difficulty of percutaneous electrode placement. A history of percutaneous cylindrical electrode placement did not affect the success of current placement, although it lengthened the operation time.

Late Spontaneous Migration of a Dorsal Column Stimulator Paddle Lead

The most frequently encountered complication of dorsal column stimulators is lead migration. The vast majority of these events are seen in the first few weeks to months. Late paddle lead migration is a very uncommon occurrence in this setting. We describe a case of a 51-year-old male with a history of reflex sympathetic dystrophy having undergone dorsal column stimulator insertion at the level of C1-C2. A good clinical benefit was appreciated in the postoperative period once the stimulator was turned on. Approximately six months postoperatively, the patient suddenly lost coverage. Radiographic imaging revealed that the lead had migrated caudally to the C3-C4 level. Subsequent revision surgery took place. This description highlights a common complication, but occurring outside the expected time frame after surgery.

Interventional Therapies for Chronic Low Back Pain: A Focused Review (Efficacy and Outcomes)

Context:

Lower back pain is considered to be one of the most common complaints that brings a patient to a pain specialist. Several modalities in interventional pain management are known to be helpful to a patient with chronic low back pain. Proper diagnosis is required for appropriate intervention to provide optimal benefits. From simple trigger point injections for muscular pain to a highly complex intervention such as a spinal cord stimulator are very effective if chosen properly. The aim of this article is to provide the reader with a comprehensive reading for treatment of lower back pain using interventional modalities.

Evidence Acquisition:

Extensive search for published literature was carried out online using PubMed, Cochrane database and Embase for the material used in this manuscript. This article describes the most common modalities available to an interventional pain physician along with the most relevant current and past references for the treatment of lower back pain. All the graphics and images were prepared by and belong to the author.

Results:

This review article describes the most common modalities available to an interventional pain physician along with the most relevant current and past references for the treatment of lower back pain. All the graphics and images belong to the author. Although it is beyond the scope of this review article to include a very detailed description of each procedure along with complete references, a sincere attempt has been made to comprehensively cover this very complex and perplexing topic.

Conclusion:

Lower back pain is a major healthcare issue and this review article will help educate the pain practitioners about the current evidence based treatment options.

Technological innovations in implants used for pain therapies

The field of pain management has experienced tremendous growth in implantable therapies secondary to the innovations of bioengineers, implanters, and industry. Every aspect of neuromodulation is amenable to innovation from implanting devices to anchors, electrodes, programming, and even patient programmers. Patients with previously refractory neuropathic pain syndromes have new and effective pain management strategies that are a direct result of innovations in implantable devices.

Spinal cord stimulation: Background and clinical application

Background Spinal cord stimulation (SCS) is a surgical treatment for chronic neuropathic pain refractory to conventional treatment. SCS treatment consists of one or more leads implanted in the epidural space of the spinal canal, connected to an implantable pulse generator (IPG). Each lead carries a number of contacts capable of delivering a weak electrical current to the spinal cord, evoking a feeling of peripheral paresthesia. With correct indication and if implanted by an experienced implanter, success rates generally are in the range of about 50-75%. Common indications include complex regional pain syndrome (CRPS I), angina pectoris, and radicular pain after failed back surgery syndrome, and the treatment is also used to treat stump pain after amputation, and pain due to peripheral nerve injury, peripheral vascular disease, and diabetic neuropathy. Recommended contraindications for the treatment include pregnancy, coagulopathy, severe addiction to psychoactive substances, and lack of ability to cooperate (e.g. due to active psychosis or cognitive impairment). Most common complications to the treatment include lead migration, lead breakage, infection, pain over the implant, and dural puncture. Despite extensive research in the area, the mechanisms of action are still only partially understood. Methods In this topical review the historical background behind the treatment is described and the current theories on the mechanism of action are presented. The implantation procedure is described in detail and illustrated with a series of intraoperative pictures. Finally, indications for SCS are discussed along with some of the controversies surrounding the therapy. Implications The reader is presented with a broad overview of spinal cord stimulation, including the historical and theoretical background, practical implantation technique, and clinical application.

Troubleshooting and problem solving: the nuances of the Epiducer

BACKGROUND AND AIMS

The study shows placement of spinal cord stimulators using an Epiducer for placement of multiple cylindrical leads or single S-8 paddle leads. It also gives tips for problem-solving Epiducer use.

OBJECTIVE

The study aims to suggest techniques that may help in solving commonly occurring difficulties with Epiducer use.

DESIGN

This is a retrospective review.

SETTING

These procedures were commonly performed in an outpatient surgery center or hospital setting.

CONCLUSION

Some problems with Epiducer placement may occur. But these problem-solving techniques may help in troubleshooting.

Technological innovation in spinal cord stimulation: use of a newly developed delivery device for introduction of spinal cord stimulation leads

OBJECTIVE

The use of multiple cylindrical leads and multicolumn and single column paddle leads in spinal cord stimulation offers many advantages over the use of a single cylindrical lead. Despite these advantages, placement of multiple cylindrical leads or a paddle lead requires a more invasive surgical procedure. Thus, the ideal situation for lead delivery would be percutaneous insertion of a paddle lead or multiple cylindrical leads. This study evaluated the feasibility and safety of percutaneous delivery of S-Series paddle leads using a new delivery device called the Epiducer lead delivery system (all St. Jude Medical Neuromodulation Division, Plano, TX, USA).

MATERIALS AND METHODS

This uncontrolled, open-label, prospective, two-center study approved by the AZ St. Lucas (Ghent) Ethics Committee evaluated procedural aspects of implantation of an S-Series paddle lead using the Epiducer lead delivery system and any adverse events relating to the device. Efficacy data during the patent's 30-day trial also were collected.

RESULTS

  Data from 34 patients were collected from two investigational sites. There were no adverse events related to the Epiducer lead delivery system. The device was inserted at an angle of either 20°-30° or 30°-40° and was entered into the epidural space at T12/L1 in most patients. The S-Series paddle lead was advanced four vertebral segments in more than 50% of patients. The average (±standard deviation [SD]) time it took to place the Epiducer lead delivery system was 8.7 (±5.0) min. The average (+SD) patient-reported pain relief was 78.8% (+24.1%).

CONCLUSIONS

This study suggests the safe use of the Epiducer lead delivery system for percutaneous implantation and advancement of the S-Series paddle lead in 34 patients.