Adverse events of sacral neuromodulation for fecal incontinence reported to the federal drug administration

Abstract

Aim: To investigate the nature and severity of AE related to sacral neurostimulation (SNS).

Methods: Based on Pubmed and Embase searches, we identified published trials and case series of SNS for fecal incontinence (FI) and extracted data on adverse events, requiring an active intervention. Those problems were operationally defined as infection, device removal explant or need for lead and/or generator replacement. In addition, we analyzed the Manufacturer and User Device Experience registry of the Federal Drug Administration for the months of August - October of 2015. Events were included if the report specifically mentioned gastrointestinal (GI), bowel and FI as indication and if the narrative did not focus on bladder symptoms. The classification, reporter, the date of the recorded complaint, time between initial implant and report, the type of AE, steps taken and outcome were extracted from the report. In cases of device removal or replacement, we looked for confirmatory comments by healthcare providers or the manufacturer.

Results: Published studies reported adverse events and reoperation rates for 1954 patients, followed for 27 (1-117) mo. Reoperation rates were 18.6% (14.2-23.9) with device explants accounting for 10.0% (7.8-12.7) of secondary surgeries; rates of device replacement or explant or pocket site and electrode revisions increased with longer follow up. During the period examined, the FDA received 1684 reports of AE related to SNS with FI or GI listed as indication. A total of 652 reports met the inclusion criteria, with 52.7% specifically listing FI. Lack or loss of benefit (48.9%), pain or dysesthesia (27.8%) and complication at the generator implantation site (8.7%) were most commonly listed. Complaints led to secondary surgeries in 29.7% of the AE. Reoperations were performed to explant (38.2%) or replace (46.5%) the device or a lead, or revise the generator pocket (14.6%). Conservative management changes mostly involved changes in stimulation parameters (44.5%), which successfully addressed concerns in 35.2% of cases that included information about treatment results.

Conclusion: With reoperation rates around 20%, physicians need to fully disclose the high likelihood of complications and secondary interventions and exhaust non-invasive treatments, including transcutaneous stimulation paradigms.

Keywords: Defecation disorders; Device registry; Implanted medical devices; Sacral nerve stimulation; Treatment complications.

Figure 1

Forrest plot showing infection rates as fraction of the sample size in cohorts treated with sacral neurostimulation for fecal incontinence.

Figure 2

Forrest plot showing explant rates as fraction of the sample size in cohorts treated with sacral neurostimulation for fecal incontinence.

Figure 3

Meta-regression showing the time dependent increase in explant. A: Q = 9.35; P = 0.002 and reoperation panel; B: Q = 20.3; P < 0.001 rates after sacral neurostimulation initiation.

Figure 4

Forrest plot showing reoperation rates as fraction of the sample size in cohorts treated with sacral neurostimulation for fecal incontinence.

Figure 5

Manufacturer and user device experience databank. A: Reports about adverse events related to therapy with Interstim are plotted as a function of month of posting by the Federal Drug Administration; B: The lower panel depicts the percentage of reports mentioning gastrointestinal problems (squares) or specifically fecal incontinence (circles) as indication for sacral neurostimulation.

Figure 6

Concerns and interventions related to Interstim treatment and described in manufacturer and user device experience. A: Depicts the number of reported events sorted based on the primary concerns; B: Shows the main corrective steps taken (“Defective Parts” refers to intra-operative problems with device components requiring exchange); C: The proportions of operatively treated interventions is plotted in relation to the overall number of reported adverse events.