Association Between Pain Scores and Successful Spinal Cord Stimulator Implantation

Clinical outcomes of spinal cord stimulation in patients with intractable leg pain in Japan

BACKGROUND

Neuromodulation through spinal cord stimulation (SCS) is a therapeutic option for relieving leg pain and improving the chances of limb salvage in patients with intractable chronic limb-threatening ischemia (CLTI); however, there is no consensus on its indications.

OBJECTIVE

The aim of this study was to assess the clinical outcomes of SCS in patients with intractable leg pain caused by various diseases treated in the department of cardiovascular medicine in Japan.

METHODS

This was a retrospective study of patients who underwent SCS for pain management. Patients were considered eligible for the therapy if they met the following criteria: (1) intractable leg pain (numerical rating scale [NRS] score of 10), (2) no revascularization option, and (3) no septicemia.

RESULTS

Twenty patients (mean age: 77 years; men/women: 11/9) were included in this study. The NRS score of the patients significantly reduced from 10 ± 0 before procedure to 4 ± 3 at discharge (p < 0.001). The clinical response rate of the entire cohort was 65% (13/20) at 17 ± 14 months after implantation; however, patients with intractable CLTI showed a low response rate (45%), whereas those with subacute limb ischemia showed a high response rate (100%). A multivariable regression analysis showed that hemoglobin level was significantly associated with treatment response, even after adjusting for age and sex (p = 0.026). The area under the receiver operating characteristic curve for the correlation between hemoglobin level (cutoff, 11.4 g/dL) and clinical response to SCS was 0.824 (0.619-1).

CONCLUSIONS

SCS can reduce clinical symptoms in majority of patients with intractable leg pain. Although implantation of an SCS device has been shown to improve microvascular perfusion insufficiency, the correlation between hemoglobin level and the clinical effect of SCS indicates that a preserved microcirculatory vascular bed is essential for the therapy to be effective.

Role of patient selection and trial stimulation for spinal cord stimulation therapy for chronic non-cancer pain: a comprehensive narrative review

Background/importance

Patient selection for spinal cord stimulation (SCS) therapy is crucial and is traditionally performed with clinical selection followed by a screening trial. The factors influencing patient selection and the importance of trialing have not been systematically evaluated.

Objective

We report a narrative review conducted to synthesize evidence regarding patient selection and the role of SCS trials.

Evidence review

Medline, EMBASE and Cochrane databases were searched for reports (any design) of SCS in adult patients, from their inception until March 30, 2022. Study selection and data extraction were carried out using DistillerSR. Data were organized into tables and narrative summaries, categorized by study design. Importance of patient variables and trialing was considered by looking at their influence on the long-term therapy success.

Findings

Among 7321 citations, 201 reports consisting of 60 systematic reviews, 36 randomized controlled trials (RCTs), 41 observational studies (OSs), 51 registry-based reports, and 13 case reports on complications during trialing were included. Based on RCTs and OSs, the median trial success rate was 72% and 82%, and therapy success was 65% and 61% at 12 months, respectively. Although several psychological and non-psychological determinants have been investigated, studies do not report a consistent approach to patient selection. Among psychological factors, untreated depression was associated with poor long-term outcomes, but the effect of others was inconsistent. Most RCTs except for chronic angina involved trialing and only one RCT compared patient selection with or without trial. The median (range) trial duration was 10 (0–30) and 7 (0–56) days among RCTs and OSs, respectively.

Conclusions

Due to lack of a consistent approach to identify responders for SCS therapy, trialing complements patient selection to exclude patients who do not find the therapy helpful and/or intolerant of the SCS system. However, more rigorous and large studies are necessary to better evaluate its role.

Patient Selection for Spinal Cord Stimulation in Treatment of Pain: Sequential Decision-Making Model - A Narrative Review

Despite the well-known efficacy of spinal cord stimulation (SCS) in chronic pain management, patient selection in clinical practice remains challenging. The aim of this review is to provide an overview of the factors that can influence the process of patient selection for SCS treatment. A sequential decision-making model is presented within a tier system that operates in clinical practice. The first level incorporates the underlying disease as a primary indication for SCS, country-related reimbursement rules, and SCS screening-trial criteria in combination with underlying psychological factors as initial selection criteria in evaluating patient eligibility for SCS. The second tier is aligned with the individualized approach within precision pain medicine, whereby individual goals and expectations and the potential need for preoperative optimizations are emphasized. Additionally, this tier relies on results from prediction models to provide an estimate of the efficacy of SCS in the long term. In the third tier, selection bias, MRI compatibility, and ethical beliefs are included, together with recent technological innovations, superiority of specific stimulation paradigms, and new feedback systems that could indirectly influence the decision-making of the physician. Both patients and physicians should be aware of the different aspects that influence patient selection in relation to SCS for pain management to make an independent decision on whether or not to initiate a treatment trajectory with SCS.