Anal incontinence is a common problem affecting quality of life. However, it is largely under reported due to social stigma and embarrassment.
Obstetric trauma following childbirth is a primary cause of fecal incontinence in women. Injury to the anal sphincter complex is common. The clinical diagnosis of injuried anal sphincter is insufficient due to presence of occult injuries.
Obstetric related anal incontinence was previously believed to be largely due to pudendal neuropathy however, following the advent of three dimensional ultrasound, most of these women demonstrated occult anal sphincter injury.
Strong association has been shown between anal incontinence and occult anal sphincter injury diagnosed by three dimensional ultrasound.
The role of internal anal sphincter (IAS) in the mechanism of continence is poorly understood. If IAS had been torn and or missed in repair, the results would be unsatisfactory and that explanation based on the fact that all studied incontinent patients showed IAS injury with open anal canal.
A new concept describes that, the internal anal sphincter (IAS) is a collagen- muscular tissue cylinder that surrounds the anal canal innervated by alpha-sympathetic nerve supply from the hypogastric nerves. It is surrounded in its lower part by the EAS which is a striated muscle innervated by the pudendal nerve. Damage of the IAS causes dilation of the anal canal. Open and dilated anal canal allows the rectal contents to enter the anal canal with subsequent fecal incontinence.This can explain why repair of the EAS in cases of complete perineal tear whether by end-to-end or overlapping techniques does not lead to complete fecal continence as a concomitant torn IAS is missed not diagnosed and not repaired (El hemaly et al., 2011).
Pelvic floor ultrasound is a valuable adjunct in elucidation of cause, diagnosis, and treatment of pelvic floor disorders. Three-dimensional ultrasound specifically has been shown to have many advantages over conventional imaging modalities. When using three-dimensional ultrasound, scanning times are short and the technique is noninvasive; there is less user dependency when compared with two-dimensional ultrasound, which contributes to the accuracy of measurements, there is no radiation exposure involved, and it allows for the capturing of images in real time. In addition, three-dimensional ultrasound has proved to be especially useful in the evaluation and treatment of fecal incontinence. Proper evaluation of pelvic floor muscle function, strength, and integrity is an important component of diagnosis and treatment of pelvic floor disorders. As practitioners become more familiar with the advantages and capabilities of ultrasound, this tool should become part of routine clinical practice in evaluation and management of pelvic floor disorders.
It is concluded from this studythat, three dimensional exoanal ultrasonography (transperineal and or transvaginal) is an accessible and promising method for postpartum sphincter evaluation that is apparently well tolerated by patients as well as in the evaluation of pelvic floor dysfunction which is considered to be an easy, inexpensive technique, and comfortable for most patients in addition to studying of dynamic changes during rest and during squeezing. Nowadays, it is becoming more widespread as a complementary examination in diagnostic investigations and also three dimensional exoanal ultrasonography (transperineal and or transvaginal) seems a promising method for functional studies of anal incontinence beyond the capacity of endoanal ultrasound.
It is suggested that women with evidence of damage to anal sphincter complex, complaining or not, should be subjected to three dimensional exoanal ultrasonography (transperineal and or transvaginal). Sonographic evidences of sphincteric injuries in these patients should be counseled about the risk of subsequent vaginal deliveries and the option of elective cesarean section should be considered.
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