Interventional Pain Procedures: A Narrative Review Focusing On Safety and Complications. PART 2 Interventional Procedures For Back Pain.

In patients where conservative approaches have failed to relieve from chronic pain, interventional procedures may be an option in well selected patients. In recent years there has been an increase in the use and development of invasive procedures. Concomitantly, there has also been an increase in the complications associated with these procedures. Taken this into consideration, it is important for healthcare providers to take a cautious and vigilant approach, with a focus on patient safety, in order to minimize the risk of adverse events and ensure the best possible outcome for the patient. This may include careful selection of patients for procedures, use of proper techniques and equipment, and close monitoring and follow-up after the procedure. The aim of this narrative review is to summarize the primary complications associated with commonly performed image-guided (fluoroscopy or ultrasound-guided) interventional procedures and provide strategies to reduce the risk of these complications. We conclude that although complications from interventional pain procedures can be mitigated to a certain degree, they cannot be eliminated altogether. In order to avoid adverse events, patient safety should be given considerable attention and physicians should be constantly aware of the possibility of developing complications.

Long-term safety of spinal cord stimulation systems in a prospective, global registry of patients with chronic pain.

Aim: The availability of long-term (>2 years) safety outcomes of spinal cord stimulation (SCS) remains limited. We evaluated safety in a global SCS registry for chronic pain. Methods: Participants were prospectively enrolled globally at 79 implanting centers and followed out to 3 years after device implantation. Results: Of 1881 participants enrolled, 1289 received a permanent SCS implant (1776 completed trial). The annualized rate of device explant was 3.5% (all causes), and 1.1% due to inadequate pain relief. Total incidence of device explantation >3 years was 7.6% (n = 98). Of these, 32 subjects (2.5%) indicated inadequate pain relief as cause for removal. Implant site infection (11 events) was the most common device-related serious adverse event (<1%). Conclusion: This prospective, global, real-world study demonstrates a high-level of safety for SCS with low rate of explant/serious adverse events. Clinical Trial Registration: NCT01719055 (ClinicalTrials.gov).

Real-World Outcomes Using a Spinal Cord Stimulation Device Capable of Combination Therapy for Chronic Pain: A European, Multicenter Experience.

Given the differing mechanisms thought to underlie therapeutic sub- and supra-perception-based neurostimulative modalities, Spinal Cord Stimulation (SCS) systems designed for combined delivery of these approaches may help improve analgesic outcomes and quality of life, and reduce treatment failures. This multicenter, observational case-series evaluated 188 patients with chronic back and/or leg pain implanted with an SCS device capable of sequential or simultaneous delivery of sub-perception and supra-perception stimulation programming (i.e., combination therapy) at 16 in Europe. Following implantation, patients were provided with an array of advanced supra-perception programs (e.g., paresthesia-based SCS using multiple independent current sources), and a custom set of sub-perception programs optimized with specific waveforms and/or field shapes. A mean overall pain score of 7.9 ± 1.7 (Standard Deviation (SD)) was reported pre-trial (Baseline). Overall pain was reduced by 4.4 ± 2.8 points (NRS) at 3-months (n = 117) and at 12 months post-implant (n = 90), respectively (p < 0.0001). Substantial quality-of-life (EQ-5D-5L) improvement as assessed at last follow-up was also observed (n = 60). These results suggest that an implanted SCS device capable of combination therapy, while also enabled with patient-specific waveform optimization and stimulation field targeting capabilities, can enable highly effective pain relief and improve quality of life in patients suffering with chronic pain.

A novel fast-acting sub-perception spinal cord stimulation therapy enables rapid onset of analgesia in patients with chronic pain.

Background: Treating chronic pain using sub-perception Spinal Cord Stimulation (SCS) does not elicit paresthesia but is associated with long analgesic 'wash-in' (i.e. duration until maximum pain relief) and prolonged assessment of therapy. We describe the attainment of clinically meaningful and rapid-onset analgesic outcomes using a novel sub-perception SCS approach.Methods: This observational case-series evaluated patients implanted with an SCS device for chronic pain, who underwent re-programming utilizing a new methodology in which paresthesia was used to guide sub-perception stimulation field targeting at specific parameters including charge-balanced symmetrical pulses at 90 Hz (termed Fast-Acting Sub-Perception Therapy, FAST). Pain scores (NRS) were collected as reported per standard-of-care from patient charts.Results: Mean overall pain score at baseline was 8.4 ± 0.2 (n = 41). After activation of FAST, a 7.1-point reduction in overall pain score was (1.3 ± 0.2, p < 0.0001) reported within 11.2 ± 1.9 minutes (n = 34). This decrease in pain score was sustained out to 3-month (1.6 ± 0.3, n = 26) and 6-month follow-up (1.7 ± 0.4, n = 18). At last follow up (mean = 223 ± 132 days), a pain score of 1.6 ± 0.3, n = 30 was determined.Conclusions: After FAST implementation, a profound analgesic response, requiring substantially less energy than conventional sub-perception methodologies, was observed. This rapid analgesic onset achieved with the novel FAST technique suggests the potential for an alternative mechanism of action(s) of sub-perception SCS.

Effects of Rate on Analgesia in Kilohertz Frequency Spinal Cord Stimulation: Results of the PROCO Randomized Controlled Trial.

OBJECTIVE: The PROCO RCT is a multicenter, double-blind, crossover, randomized controlled trial (RCT) that investigated the effects of rate on analgesia in kilohertz frequency (1-10 kHz) spinal cord stimulation (SCS). MATERIALS AND METHODS: Patients were implanted with SCS systems and underwent an eight-week search to identify the best location ("sweet spot") of stimulation at 10 kHz within the searched region (T8-T11). An electronic diary (e-diary) prompted patients for pain scores three times per day. Patients who responded to 10 kHz per e-diary numeric rating scale (ED-NRS) pain scores proceeded to double-blind rate randomization. Patients received 1, 4, 7, and 10 kHz SCS at the same sweet spot found for 10 kHz in randomized order (four weeks at each frequency). For each frequency, pulse width and amplitude were titrated to optimize therapy. RESULTS: All frequencies provided equivalent pain relief as measured by ED-NRS (p ≤ 0.002). However, mean charge per second differed across frequencies, with 1 kHz SCS requiring 60-70% less charge than higher frequencies (p ≤ 0.0002). CONCLUSIONS: The PROCO RCT provides Level I evidence for equivalent pain relief from 1 to 10 kHz with appropriate titration of pulse width and amplitude. 1 kHz required significantly less charge than higher frequencies.

A Spinal Cord Stimulation Service Review From a Single Centre Using a Single Manufacturer Over a 7.5 Year Follow-Up Period.

BACKGROUND: Spinal cord stimulation (SCS) is a recognized management option for patients with refractory neuropathic pain. Despite randomized controlled trials reporting the effectiveness of SCS, there is a lack of long-term data reflecting usual SCS practice. The aim of this study is to present the long-term outcomes of a cohort of patients from a single centre undertaking SCS with devices from a single manufacturer. METHODS: Data were collected between January 2008 and July 2015 on 321 patients who had an SCS trial. Outcome measures included numerical rating scale of pain intensity (NRSPI), brief pain inventory (BPI), EQ5D and quality-adjusted life-years (QALYs). Adverse effects also were recorded. RESULTS: Statistically significant reductions in NRSPI and BPI and increases in health utility using the EQ5d were observed. SCS over a 15-year time period resulted in a mean projected gain of 6.2 QALY. The rates of implant infection and device explantation were 2.3% (2.4% not including legacy patients) and 6.7% (7.6% not including legacy patients) respectively but only 3.4% (4% excluding legacy patients) explanted due to late failure to relieve pain. Satisfaction with SCS was high with 92% of patients stating that they would have it all done again for the same result. 96.4% would have wanted SCS as a treatment option earlier. CONCLUSIONS: Patients with neuropathic pain undertaking SCS experience long-term reductions in pain intensity and increases in health utility and associated QALY gains. The findings from this study associated with the increased longevity of rechargeable SCS devices suggest that the cost-effectiveness of SCS may become increasingly favourable when compared with conventional medical management.

The Neurostimulation Appropriateness Consensus Committee (NACC) Recommendations for Infection Prevention and Management.

INTRODUCTION: The use of neurostimulation for pain has been an established therapy for many decades and is a major tool in the arsenal to treat neuropathic pain syndromes. Level I evidence has recently been presented to substantiate the therapy, but this is balanced against the risk of complications of an interventional technique. METHODS: The Neurostimulation Appropriateness Consensus Committee (NACC) of the International Neuromodulation Society convened an international panel of well published and diverse physicians to examine the best practices for infection mitigation and management in patients undergoing neurostimulation. The NACC recommendations are based on evidence scoring and peer-reviewed literature. Where evidence is lacking the panel added expert opinion to establish recommendations. RESULTS: The NACC has made recommendations to improve care by reducing infection and managing this complication when it occurs. These evidence-based recommendations should be considered best practices in the clinical implantation of neurostimulation devices. CONCLUSION: Adhering to established standards can improve patient care and reduce the morbidity and mortality of infectious complications in patients receiving neurostimulation.

A Retrospective, Long-term, Third-Party Follow-up of Patients Considered for Spinal Cord Stimulation.

The objective of this study was to follow up patients considered for spinal cord stimulation and assess outcomes and patient selection factors associated with outcome. A retrospective study of patients considered for spinal cord stimulation was performed. This included three groups: A) those who did not have a temporary trial of stimulation, B) those who did not go on to have long-term stimulation after a trial, and C) those who did go on to have long-term stimulation after a trial. Patient notes were obtained, a structured telephone interview conducted, and patients returned a questionnaire. VAS scores, percentage pain reduction reported, quality of life reports, Oswestry Disability Index and Hospital Anxiety and Depression Indices were recorded. Fifty-two percent of patients who had long-term stimulation reported 50% or greater pain reduction. In the subset of these patients with the diagnosis of failed back surgical syndrome, 51% reported 50% or greater pain reduction. Significant improvements in VAS, Oswestry Disability Index, and depression were reported pre and post long-term stimulation. There were significant differences in the quality-of-life reports between the patients who received long-term stimulation (who showed a positive outcome) and those who did not (who showed a negative outcome); 80% of patients receiving long-term stimulation reported an improvement in their quality of life. Follow-up of a cohort of patients receiving long-term stimulation demonstrated some reduction of treatment efficacy. Use of a psychological interview aided patient selection, but no other factors showed a correlation with reported pain reduction. No serious adverse effects were demonstrated. A revision rate of 23.5% occured in long-term stimulated patients. We conclude that spinal cord stimulation is an efficacious therapy which is not associated with serious side effects. There is some reduction in therapeutic efficacy over time. Patients deteriorate without treatment.