Injectable and Implantable Agents: Current Evidence and Perspective

Ratto C., Parello A., Donisi L., Litta F.
Management of Fecal Incontinence, M. Mongardini, M. Giofrè (eds.), 2016 pp. 91-105

Multifactorial etiology of fecal incontinence (FI) has a significant impact on the choice of management. Sphincter lesions are considered the main cause of FI, particularly in female patients, but frequently the dysfunction occurs also in subjects with intact sphincters. In other cases, neuropathy (either peripheral or central) plays the pivotal role, causing sensory-motor alterations. Also the severity of FI can be variable, ranging from soiling, seepage, and incontinence to gas (commonly defined as “minor incontinence”) to incontinence to liquid and solid stools (defined as “major incontinence”). Despite the numerous modalities of treatment available, the therapeutic efficacy is still suboptimal for all of them. In fact, “conservative” therapies such as biofeedback have high failure rates, while the success of “minimally invasive” procedures such as bulking agents, radiofrequency, and tibial and sacral nerve stimulation or “aggressive” procedures such as anal sphincteroplasty, graciloplasty, artificial bowel sphincter, and magnetic sphincter ranges from partial success to complete failure. Specifically, injection of bulk-enhancing agents into the anal canal to treat FI has continued to gain popularity. Ideally, any bulking agent for injection should be biocompatible, nonallergenic, non-immunogenic, and easy to inject and should not migrate within the tissues. Traditionally, the bulking agents have been “injected.” However, more recently different materials have been introduced in clinical practice and delivered by “implantation.”