Octreotide acts on anorectal physiology: a dynamic study in healthy subjects

Effects of transcutaneous tibial nerve stimulation on anorectal physiology in fecal incontinence: a double-blind placebo-controlled cross-over evaluation

BACKGROUND

Transcutaneous electrical tibial nerve stimulation (TENS) is of growing interest for the treatment of fecal incontinence (FI), but its mechanism of action remains uninvestigated. We aimed to further assess the anorectal response to TENS in a dynamic model.

METHODS

We performed a placebo-controlled, randomized, double-blinded crossover study in 19 patients suffering from FI to assess the effects of TENS on anorectal function. Anorectal physiology and perception were recorded through two sequences of rectal isobaric distension using an electronic barostat device to measure anal and rectal pressures, rectal volumes, and perception scores.

KEY RESULTS

Maximal rectal pressure and volume variation were affected by TENS, with higher mean maximal rectal pressure (5.33 and 4.06 mmHg in the active and sham TENS respectively, p < 0.0001) and lower volume variation (11.45 and 14.7 mL in the active and sham stimulation respectively, p < 0.05). Rectal compliance was not modified by active TENS. Pressure of the upper anal canal was significantly lower with raised isobaric distension in sequences assigned to active TENS.

CONCLUSIONS & INFERENCES

Acute TENS modified anorectal physiology by strengthening the myogenic response to distension rather than increasing muscle relaxation and related rectal compliance in patients with FI.

Elastomer implants in faecal incontinence: a blind, randomized placebo-controlled study

AIM

To test efficacy and safety of polydimethylsiloxane elastomer implants, a silicone biomaterial, in patients with severe faecal incontinence related to an impaired internal anal sphincter.

METHODS

Subjects were randomized to receive three injections of 2.5 mL of either physiological saline or polydimethylsiloxane elastomer. After local anaesthesia, an 18 gauge, 2.5-in needle was inserted through the perianal skin and laid down into the intersphincteric space. Treatment (saline or polydimethylsiloxane elastomer) was administered by means of a ratchet gun. Three injections of 2.5 mL each were performed in the area of the internal anal sphincter at 3, 7 and 11 o'clock positions. Main end point was the percentage of subjects in each treatment arm experiencing a successful treatment, defined as a Cleveland Clinic Florida-Faecal Incontinence score <8, 3 months after treatment. Secondary end points were quality of life scores, weekly number of faecal incontinence episodes, subject acceptance and adverse events rate. Both patients and end point assessments were blinded to treatment.

RESULTS

44 women (64.3 +/- 9 years) with a baseline Cleveland Clinic Florida-Faecal Incontinence score > or =8 were enrolled prospectively; 22 received polydimethylsiloxane elastomer and 22 saline treatment. Treatment was well tolerated. At 3 months, the percentage of subjects experiencing a successful treatment was not different between polydimethylsiloxane elastomer and saline groups (23% vs. 27%, respectively, P = 0.73). Moreover, Cleveland Clinic Florida-Faecal Incontinence score was not significantly different between polydimethylsiloxane elastomer and saline groups (11.7 +/- 4.7 vs. 11.4 +/- 4.5, respectively, P = 0.79).

CONCLUSIONS

Polydimethylsiloxane elastomer implants cannot be recommended for treatment of severe faecal incontinence related to impaired internal anal sphincter.

Low rectal volumes in patients suffering from fecal incontinence: what does it mean?

BACKGROUND

Rectal perception and adaptation to distension are widely heterogeneous in subjects with faecal incontinence.

AIM

To quantify rectal physiology in patients with incontinence and low maximum rectal volume, according to AGA guidelines on anorectal testing techniques.

PATIENTS AND METHODS

148 patients (12 men, 136 female) with incontinence to liquid and/or solid stools were investigated. Distending isobaric procedures were carried out using an electronic barostat in order to analyse perception and adaptation of the rectum.

RESULTS

Pain during isovolumic rectal distension at a level of 100 mL or less was experienced in 21 subjects (14.2%). As defined by isobaric distensions, incontinent patients with low MTV had more frequently a hypocompliant rectum (62%) when compared with those with higher MTV (31%, P = 0.046). Perception scores tended to be higher at each step of distending rectal pressure: incontinent patients with low MTV had more frequently a hypersensitive rectum (48%) when compared with those with normal or high MTV (24%, P = 0.035). Only four of 21 incontinent subjects with low MTV had an isolated hypersensitive rectum.

CONCLUSION

Both sensitivity and compliance are altered in patients with low MTV. A more extensive study of the role of sensory and compliance aspects of subjects with incontinence is warranted.

Differential effects of two types of antidepressants, amitriptyline and fluoxetine, on anorectal motility and visceral perception

BACKGROUND

Although antidepressants are used for functional gastrointestinal disorders, the mechanisms of their effects on gut are incompletely understood.

AIM

To assess the effects of two types of antidepressants (tricyclic, serotoninergic) on anorectal motility and visceral perception.

METHODS

A placebo-controlled, randomized, double-blind, crossover study was performed in 12 healthy male volunteers who received a single oral dose of amitriptyline (80 mg), fluoxetine (40 mg) or placebo. Drug effects were assessed using phasic isobaric distensions of the rectum with an electronic barostat (11 levels from 1 to 51 mmHg) 4 h after drug intake. Maximal rectal volume and pressure, mean and residual pressures at upper anal canal, mean pressure at lower anal canal, defecation sensation (5-level scale) and visceral perception (visual analogue scale) were recorded at each level of distending pressure.

RESULTS

Ten subjects completed the study. Compared with placebo, neither amitriptyline nor fluoxetine modified rectal compliance or visceral perception. Compared with placebo, antidepressants significantly reduced mean and residual pressures at upper anal canal (-18%, P = 0.0019, and -27%, P = 0.0002, respectively, for amitriptyline; -26%, P = 0.0001, and -33%, P = 0.0001, respectively, for fluoxetine) whereas only amitriptyline significantly reduced mean pressure at lower anal canal (-16%, P = 0.0008).

CONCLUSION

Both antidepressants similarly relaxed the internal anal sphincter, probably through a non-specific mechanism, without modifying visceral perception. Only amitriptyline relaxed the external anal sphincter.