Pelvic Floor and Functional Disorders
Core concepts
Understand the physiology of continence and defecation: anal sphincter complex, puborectalis, and the rectoanal inhibitory reflex. Differentiate fecal incontinence causes (sphincter injury, neuropathy, diarrhea, rectal prolapse) and treatments from biofeedback and bulking to sacral neuromodulation and sphincter repair. Know obstructed defecation and dyssynergic defecation, diagnosed by anorectal manometry and balloon expulsion; treat with biofeedback. Recognize rectal prolapse (full-thickness versus mucosal) and surgical approaches (perineal versus abdominal).
Traps
Questions test whether you order physiologic testing before surgery for constipation or incontinence. Another trap: attributing obstructed defecation to slow transit without manometry. Watch for the misconception that biofeedback is inferior to surgery for dyssynergia-it is first-line. Also know that sacral neuromodulation requires intact sacral nerves and trial evaluation.
Worked example
A woman with fecal urgency and incontinence after obstetric injury, with a sphincter defect on endoanal ultrasound: consider overlapping sphincteroplasty, but first optimize stool consistency and trial biofeedback. Rule of thumb: physiologic testing (manometry, balloon expulsion, ultrasound) should precede operative intervention for functional complaints.