European Journal of Obstetrics & Gynecology and Reproductive Biology
MRI morphology of the levator ani muscle, endopelvic fascia, and urethra in women with stress urinary incontinence
Introduction
Magnetic resonance imaging (MRI) provides detailed morphologic information on the stress urinary continence mechanism in vivo which correlates with findings in anatomic specimens [1], [2], [3], [4], [5] and even allows for assessing tissue quality [6]. Standardized MRI protocols [7] ensure interindividual morphologic comparison of the stress urinary continence mechanism. Delivery-related changes of this mechanism are depicted and can be classified as reversible and irreversible structural changes by repeat examination [6]. Interindividual comparison of the stress urinary continence mechanism in a homogeneous study population (nulliparae with normal urogynecologic findings) suggests that normal anatomic variations exist [7], which are assumed to contribute to the fact that the morphometry of the structures constituting the stress urinary continence mechanism in women with stress urinary incontinence is not significantly different from that of healthy women [8]. Qualitative changes such as the loss of the symphyseal concavity of the anterior vaginal wall are significantly more common in women with stress urinary incontinence [2], [8], [9], but have also been reported in women without symptoms [8]. It is still unclear whether these changes are constitutional or delivery-related.
Available MRI studies of the anatomy and pathology of the stress urinary continence mechanism have been performed in small, inhomogeneous study populations and the results do not yet allow for clearly defining the role of MRI in the diagnostic assessment of stress urinary incontinence. But the data do show that MRI clearly depicts the morphology and topography of the stress urinary continence mechanism. Open questions regarding the pathogenesis of stress urinary incontinence should therefore be answered making use of MRI [10], [11], [12]. The aim of the present study therefore was to identify stress-urinary-incontinence-related changes of the stress urinary continence mechanism consisting of the levator ani muscle, endopelvic fascia, and urethra as they are depicted by MRI. Based on these findings, a terminology of the MRI pathomorphology of the stress urinary continence mechanism in women with stress urinary continence is suggested.
Section snippets
Patients
Fifty-four women (mean age 52.1 ± 10.5 years; range 23–78 years; 75.9% aged 41–60 years) with proven stress urinary incontinence based on history (grade II according to Ingelman-Sundberg), clinical findings (positive stress test) [13], and urodynamic testing (sensory or motor urge symptoms were excluded in all women) were examined by MRI. MRI was performed in all women as part of their preoperative diagnostic workup after informed consent had been obtained. Women who additionally had clinically
Results
The pulse sequences used yielded analyzable images in all 54 cases.
Discussion
Defects of the levator ani muscle in the form of a unilateral loss of substance were rare in our patient population suggesting that such defects, while leading to mechanical dysfunction [16], are not the primary cause of stress urinary incontinence. The low incidence of levator ani defects alone in our study may be due to the fact that all patients were scheduled for urinary incontinence surgery. Our policy is to only operate on patients with proven reactivity of the pelvic floor or who have
References (46)
- et al.
The anatomy of stress incontinence: magnetic resonance imaging of the female bladder neck and urethra
J Urol
(1990) - et al.
Magnetic resonance imaging anatomy of the female urethra: a direct histologic comparison
Obstet Gynecol
(1996) - et al.
Magnetic resonance imaging of the levator ani with anatomic correlation
Obstet Gynecol
(1996) - et al.
Visibility of pelvic organ support system structures in magnetic resonance images without an endovaginal coil
Am J Obstet Gynecol
(2001) Stress urinary incontinence: where are we now, where should we go? [see comments]
Am J Obstet Gynecol
(1996)- et al.
The standardization of terminology of female pelvic organ prolapse and pelvic floor dysfunction
Am J Obstet Gynecol
(1996) - et al.
Age changes in the human female urethra: a morphometric study
J Urol
(1988) - et al.
Role of fascial collagen in stress urinary incontinence
Am J Obstet Gynecol
(1998) - et al.
Injury to innervation of pelvic floor sphincter musculature in childbirth
Lancet
(1984) - et al.
Age effects on urethral striated muscle. II. Anatomic location of muscle loss
Am J Obstet Gynecol
(2002)
Sectional depiction of the pelvic floor by CT, MR imaging and sheet plastination: computer-aided correlation and 3D model
Eur Radiol
Female pelvic floor: endovaginal MR imaging of normal anatomy
Radiology
MR imaging of levator ani muscle recovery following vaginal delivery
Int Urogynecol J Pelvic Floor Dysfunct
Static magnetic resonance imaging of the pelvic floor muscle morphology in women with stress urinary incontinence and pelvic prolapse
Neurourol Urodyn
Magnetic resonance imaging of defects in DeLancey's vaginal support levels I, II, and III
Am J Obstet Gynecol
Magnetic resonance imaging of the lower urinary tract
Curr Opin Obstet Gynecol
Contribution of MRI in diagnosis of urinary stress incontinence without concomitant urogenital prolapse
RöFo
Urinary incontinence in women, excluding fistulas
Acta Obstet Gynecol Scand
Anatomical variations in the levator ani muscle, endopelvic fascia, and urethra in nulliparas evaluated by MR imaging
Am J Obstet Gynecol
New aspects in pathophysiology of female urinary incontinence
Denervation syndromes of the shoulder girdle: MR imaging with electrophysiologic correlation
Skeletal Radiol
Correlation between quantitative EMG and muscle MRI in patients with axonal neuropathy
Muscle Nerve
Magnetic resonance imaging of denervated muscle: comparison to electromyography
Muscle Nerve
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