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. 2021 Mar;25(18):1–96. doi: 10.3310/hta25180

Sacral nerve stimulation versus the magnetic sphincter augmentation device for adult faecal incontinence: the SaFaRI RCT.

David G Jayne, Annabelle E Williams, Neil Corrigan, Julie Croft, Alison Pullan, Vicky Napp, Rachel Kelly, David Meads, Armando Vargas-Palacios, Adam Martin, Claire Hulme, Steven R Brown, Karen Nugent, Jen Lodge, David Protheroe, Sushil Maslekar, Andrew Clarke, Pasha Nisar, Julia M Brown
PMCID: PMC8020198  PMID: 33752794

Abstract

BACKGROUND

Preliminary studies using the FENIX™ (Torax Medical, Minneapolis, MN, USA) magnetic sphincter augmentation device suggest that it is safe to use for the treatment of adult faecal incontinence, but efficacy data are limited.

OBJECTIVE

To compare FENIX with sacral nerve stimulation for the treatment of adult faecal incontinence in terms of safety, efficacy, quality of life and cost-effectiveness.

DESIGN, SETTING AND PARTICIPANTS

Multicentre, parallel-group, unblinded, randomised trial comparing FENIX with sacral nerve stimulation in participants suffering moderate to severe faecal incontinence.

INTERVENTIONS

Participants were randomised on an equal basis to either sacral nerve stimulation or FENIX. Follow-up occurred 2 weeks postoperatively and at 6, 12 and 18 months post randomisation.

MAIN OUTCOME AND MEASURE

The primary outcome was success, defined as device in use and ≥ 50% improvement in Cleveland Clinic Incontinence Score at 18 months post randomisation. Secondary outcomes included complication rates, quality of life and cost-effectiveness. Between 30 October 2014 and 23 March 2017, 99 participants were randomised across 18 NHS sites (50 participants to FENIX vs. 49 participants to sacral nerve stimulation). The median time from randomisation to FENIX implantation was 57.0 days (range 4.0-416.0 days), and the median time from randomisation to permanent sacral nerve stimulation was 371.0 days (range 86.0-918.0 days). A total of 45 out of 50 participants underwent FENIX implantation and 29 out of 49 participants continued to permanent sacral nerve stimulation. The following results are reported, excluding participants for whom the corresponding outcome was not evaluable. Overall, there was success for 10 out of 80 (12.5%) participants, with no statistically significant difference between the two groups [FENIX 6/41 (14.6%) participants vs. sacral nerve stimulation 4/39 (10.3%) participants]. At least one postoperative complication was experienced by 33 out of 45 (73.3%) participants in the FENIX group and 9 out of 40 (22.5%) participants in the sacral nerve stimulation group. A total of 15 out of 50 (30%) participants in the FENIX group ultimately had to have their device explanted. Slightly higher costs and quality-adjusted life-years (incremental = £305.50 and 0.005, respectively) were observed in the FENIX group than in the sacral nerve stimulation group. This was reversed over the lifetime horizon (incremental = -£1306 and -0.23 for costs and quality-adjusted life-years, respectively), when sacral nerve stimulation was the optimal option (net monetary benefit = -£3283), with only a 45% chance of FENIX being cost-effective.

LIMITATIONS

The SaFaRI study was terminated in 2017, having recruited 99 participants of the target sample size of 350 participants. The study is, therefore, substantially underpowered to detect differences between the treatment groups, with significant uncertainty in the cost-effectiveness analysis.

CONCLUSIONS

The SaFaRI study revealed inefficiencies in the treatment pathways for faecal incontinence, particularly for sacral nerve stimulation. The success of both FENIX and sacral nerve stimulation was much lower than previously reported, with high postoperative morbidity in the FENIX group.

FUTURE WORK

Further research is needed to clarify the treatment pathways for sacral nerve stimulation and to determine its true clinical and cost-effectiveness.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN16077538.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 25, No. 18. See the NIHR Journals Library website for further project information.

Plain language summary

Faecal incontinence is a distressing condition for patients, and surgery is recommended if symptoms are having an effect on quality of life. One of the treatments recommended for faecal incontinence by the National Institute for Health and Care Excellence is sacral nerve stimulation, which aims to improve continence by stimulating the nerves to the back passage. A newer treatment involves surgery to implant a string of magnetic beads around the anal canal using the FENIX™ device (Torax Medical, Minneapolis, MN, USA). The aim of this study was to assess the benefits and risks of the FENIX device compared with sacral nerve stimulation. The SaFaRI study aimed to recruit 350 participants with faecal incontinence, but was stopped early because of the manufacturer withdrawing the FENIX device for strategic reasons. In total, we recruited 99 participants. Fifty participants were allocated to receive the FENIX device and 49 participants were allocated to receive sacral nerve stimulation. The observed success rates with both devices were low: at 18 months following their entry into the study, 6 out of 41 (14.6%) participants in the FENIX group and 4 out of 39 (10.3%) participants in the sacral nerve stimulation group had the device both in use and producing a benefit. A total of 5 out of 50 (10.0%) participants allocated to receive the FENIX device did not have a device implanted, and 15 out of 45 (33.3%) participants who did have the FENIX device implanted needed to have it removed because of complications during the 18-month follow-up period. A total of 21 out of 49 (42.9%) participants allocated to receive sacral nerve stimulation did not have a permanent sacral nerve stimulation device implanted, and 0 of the 28 who did have a permanent sacral nerve stimulation device implanted needed to have it removed during the 18-month follow-up period. The costs associated with the FENIX device were higher because of a greater number of participants experiencing complications, meaning that the FENIX device is unlikely to be cost-effective in the treatment of faecal incontinence compared with sacral nerve stimulation.

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