Meanwhile, a sophisticated magnetic device to reinforce the lower esophageal sphincter based on the same mechanism was manufactured, which appeared on the clinical scene in 2008. It was experimented on patients with gastroesophageal reflux by Bonavina , under the name of LINX magnetic sphincter augmentation (MSA), produced by TORAX Medical, Inc. Share View, Minnesota, USA. Subsequently, in 2010, Lehur published an article concerning the treatment of patients with fecal incontinence by means of a magnetic device named FENIX magnetic anal sphincter augmentation (MAS) produced by the same company, which was similar to the previous one.
The magnetic anal sphincteris made up of a series of titanium beads with magnetic cores connected with a flexible titanium wire along which they may slide one against the other, being attracted by their magnetic force []. This string of beads, also called a “magnetic collar”, is surgically placed in a tunnel around the anal canal, adapting the number of magnets to the previously measured circumference to surround and tighten. The increase in pressure inside the anal lumen during the evacuation moves the beads away along the wire, widening the collar and consequently the anal lumen, thus enabling the passage of feces. After evacuation, the endoluminal pressure decreases and the collar tightens again, closing the lumen.
Figure 2. Magnetic anal sphincter augmentation device: closed (left); and open (right). From: Ref. (Reprinted with permission).
*Statistically significant; at six months; NS: statistically not significant; FI: fecal incontinence; MAS: magnetic anal sphincter; FIQoL: fecal incontinence quality of life; CCF-IS: Cleveland Clinic Florida Incontinence Severity.
Comparison between the clinical outcomes of patients undergoing magnetic anal sphincter and artificial bowel sphincter implantations drawn from the study by Wong (2011)and a comparison between those of magnetic anal sphincter and sacral nerve stimulation from the study by Wong (2012)
