Advice

Clinical and technical evidence

Clinical and technical evidence

A literature search was carried out for this briefing in accordance with NICE's interim process and methods statement. 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

Four studies are summarised in this briefing. This includes 2 randomised controlled trials and 2 prospective studies. A total of 423 people are included in these studies.

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

Overall assessment of the evidence

The studies were in relevant populations, including women in labour and people with obesity. However, 2 of the studies specifically excluded people with known spinal deformities or severe scoliosis, so the device's effectiveness in this population cannot be assessed. Only 1 study compared the Accuro device with conventional ultrasound to assess its sensitivity and specificity. This study was limited by being an imaging-only study that did not look at how accurate the measurements were compared with needle placement. From the limited evidence available, it does appear that using Accuro could benefit spinal or epidural anaesthesia administration in people with obesity. However, further studies would be needed to confirm this. None of the studies were done in the UK and so the evidence may not be generalisable to the NHS. However, an expert noted that needle placement techniques are unlikely to vary between countries. The company highlights that there is clinical evidence that spinal or epidural ultrasound in general improves safety (Perlas et al. 2016) by reducing traumatic needle placements.

Singla et al. (2019)

Intervention and comparator(s)

Intervention: ultrasound using Accuro in the SpineNav3D mode.

Comparators: palpation only, and palpation plus Accuro in the SpineNav3D mode.

Key outcomes

People who had ultrasound only or ultrasound with palpation had 15% fewer needle insertions, 26% fewer needle passes, and a 33% shorter needle insertion time than people who had palpation only. However, these differences were not significant. In the subgroup of people with obesity, there were significantly fewer needle insertions (21%; p=0.025) and needle passes (38%; p=0.030) compared with palpation alone. There was also a 58% reduction in difficult spinals (those requiring more than 10 needle passes; p=0.011) in this group.

Strengths and limitations

This randomised controlled trial evaluated ultrasound using the Accuro device by resident physicians who had minimal training in ultrasonography. They analysed the results in a subgroup of people with obesity, because it is this subgroup who are most likely to benefit from the device. However, there were people with obesity in the ultrasound groups (p=0.027), which could have affected the results. This study lacked sufficient statistical power to draw firm conclusions from the results, and there was no blinding of the investigators or patients, which could have introduced bias.

Seligman et al. (2018)

Intervention and comparator(s)

Intervention: ultrasound using Accuro with no palpation.

No comparator.

Key outcomes

Mean needle depth in the epidural space was 0.61 cm less than the actual needle depth needed (95% confidence interval [CI] -0.79 to -0.44). Using the ultrasound-identified insertion point led to successful epidural placement at first attempt in 87% of people, including 78% without needle redirects.

Strengths and limitations

This was a small single-armed study looking at device accuracy only. The ultrasound measures were all done by 1 person who was proficient at using the device. The person placing the needle for the epidural was blinded to the ultrasound depth measures. People with severe scoliosis were excluded from this study.

Capogna et al. (2018)

Intervention and comparator(s)

All participants had scans using conventional ultrasound and Accuro with SpineNAV3D technology.

No comparator.

Key outcomes

The study found that the Accuro device detected the epidural space with a sensitivity of 94.2% (95% CI 85.1 to 98.1) and a specificity of 85.5% (95% CI 81.7 to 88.6). It measured its depth with an error of around plus or minus 0.5 cm compared with conventional ultrasound.

Strengths and limitations

This study was done with healthy pregnant women at term, who did not have obesity, in whom identifying epidural location would be easier. Because this was an imaging-only study, actual depths and needle placement location were not done to check the accuracy of either ultrasound method.

Ghisi et al. (2019)

Intervention and comparator(s)

Intervention: preprocedural ultrasound scan with Accuro to identify the needle insertion point.

Comparator: palpation of cutaneous landmarks.

Key outcomes

Three needle redirections were needed with Accuro (interquartile range [IQR] 0 to 9) compared with 6 in the control group (IQR 1 to 16; p=0.008). One pass through the skin was needed with Accuro (IQR 1 to 2) and 1 was needed in the control group (IQR 1 to 3; p=0.019). However, Accuro had a longer procedural time than the control (558 seconds [range 232] compared with 348 seconds [range 255]; p<0.001).

Strengths and limitations

This was a short technical briefing of a randomised controlled trial. Although the trial reports data from more than 100 people from a relevant population, it is limited by the information available to assess the quality of the evidence.

Sustainability

The company claims the technology can reduce incorrect needle selection and thereby reduce the number of needles needed. This is because Accuro can estimate the depth of the epidural space, which can be used to select the appropriate needle length. There is no published evidence to support this claim. Improved safety, by having more accurate needle placements (Perlas et al. 2016), could reduce the need for further hospital treatment and reduce use of hospital resources. The device contains a non-replaceable rechargeable lithium ion battery. The sterile cover and locator needle guide are single use only.

Recent and ongoing studies