Advice

Clinical and technical evidence

Clinical and technical evidence

A literature search was carried out for this briefing in accordance with the interim process and methods statement for medtech innovation briefings. This briefing includes the most relevant or best available published evidence relating to the clinical effectiveness of the technology. Further information about how the evidence for this briefing was selected is available on request by contacting mibs@nice.org.uk.

Published evidence

Five studies are summarised in this briefing, reporting on 87 people who had treatment with differential target multiplexed spinal cord stimulation (DTM SCS). These include 1 randomised controlled trial, 1 prospective feasibility study, a case series and 2 case reports.

The clinical evidence and its strengths and limitations is summarised in the overall assessment of the evidence.

Overall assessment of the evidence

Studies evaluating the clinical utility of DTM SCS are of variable methodological quality, but all show that DTM SCS is effective in reducing chronic back and leg pain. The highest methodological quality evidence comes from a recent randomised controlled trial (Stimgenics Open-Label, Post Market Study [SGX-SCS-RCT]) done in the USA (Fishman et al. 2021a). This trial provides direct evidence for the clinical superiority of DTM SCS compared with traditional spinal cord stimulation. Interim analyses from SGX‑SCS‑RCT have been reported in 3 abstracts (Fishman et al. 2020a, Fishman et al. 2020b and Vallejo et al. 2021). The results reported in the trial are the only ones that provide evidence for medium-term effectiveness (1 year).

There is some heterogeneity in the patient populations of the 2 prospective studies, which makes the evidence less generalisable. Additionally, the comparator in all studies is traditional (low-frequency) spinal cord stimulation (currently considered standard care). However, other modalities such as high‑density or high dose, burst, 10‑kHz high-frequency therapy, and closed‑loop spinal cord stimulation exist (Provenzano et al. 2021). There is no comparative evidence on DTM SCS against any of those.

Fishman et al. (2021a)

Intervention and comparator

DTM SCS compared with traditional spinal cord stimulation.

Key outcomes

At 3 months, an LBP responder rate of 80.1% with DTM SCS was superior to 51.2% with traditional spinal cord stimulation (p=0.0010). The mean LBP reduction (5.36 cm) with DTM SCS was greater than the reduction (3.37 cm) with traditional spinal cord stimulation (p<0.0001), based on the 10‑cm visual analogue scale (VAS). Similar results were reported for LP, with mean reductions in LP VAS of 5.29 cm with DTM SCS and 4.76 cm with traditional spinal cord stimulation (not statistically significant).

Strengths and limitations

The results were robust to sensitivity analyses (an analysis with a modified intention-to-treat population [completer's analysis], tipping point analyses and additional opioid use). The clinical utility observed at 3 months was sustained at 6 and 12 months; however, attrition rates were higher for the traditional spinal cord stimulation group. This trial was not blinded because of the nature of the programs. Some of the study authors declared financial or non-financial interests with the company.

Fishman et al. (2020c)

Intervention and comparator

Change in LBP relative to baseline after a trial period with traditional spinal cord stimulation followed by a trial period with DTM SCS.

Key outcomes

The mean baseline numeric pain rating scale (NRS) score was 7.4 (0: no pain, 10: extremely severe pain). Significant relief in back pain was observed for both treatments, with significantly better response with DTM SCS. At the end of the trial period, people reported a reduction in their mean NRS score from baseline to 4.2 (p<0.001) after traditional spinal cord stimulation and to 2.4 (p<0.001) after DTM SCS.

Strengths and limitations

This was the first study to provide evidence for the effectiveness of the technology in treating chronic pain. The duration of the trial periods was very short and does not allow estimations of the long-term effectiveness. The duration of the trial periods was also based on clinician's decision only. Some of the study authors declared financial or non-financial interests with the company.

Gunduz et al. (2021)

Intervention and comparator

Pain intensity pre-intervention and 3 months post-intervention.

Key outcomes

Pain intensity was documented using an NRS (0: no pain, 10: extremely severe pain). Preoperative mean NRS was 8.5 (range 7 to 9). Postoperative NRS was 2.6 (range 1 to 5) after 3 months.

Strengths and limitations

The study provides some limited evidence for the technology's effectiveness in people with chronic refractory back pain and no prior surgery, for whom the scientific literature is less abundant. The study is presented in abstract format only, so is limited in detail.

Brown et al. (2021)

Intervention and comparator

Pain intensity pre- and post-intervention.

Key outcomes

Pain intensity was documented using an NRS (0: no pain, 10: extremely severe pain). Pain intensity decreased from 8 pre-procedure to 3 immediately post-procedure, reaching stable relief of 80% throughout the following 4 days.

Strengths and limitations

The study is presented in abstract format only so is limited in detail and it is difficult to assess the quality and reliability of its results. It reports on a single case.

Fishman et al. (2021b)

Study size, design and location

A case report of a person with adult degenerative scoliosis who had DTM SCS in the US. The person had a single cervical electrode placed at C2.

Intervention and comparator

Pain intensity pre- and post-intervention.

Key outcomes

Pain intensity was documented using an NRS (0: no pain, 10: extremely severe pain). The overall pain score reduced by 42% from 7 to 4. A 75% subjective pain relief of neck pain, thoracic pain, lumbar pain and bilateral lower extremity pain was reported during the trial.

Strengths and limitations

This study provides evidence for the technology's effectiveness in a population for which there is limited evidence. However, the study is presented in abstract format only so is limited in detail. It reports on a single case. Some of the study authors may have financial or non-financial interests with the company.

Sustainability

The company claims that the small size and long battery life of the device may lead to sustainability benefits. There is no published evidence to support these claims.

Recent and ongoing studies