Rohna Kearney

The Appearance of Levator Ani Muscle Abnormalities in Magnetic Resonance Images After Vaginal Delivery

OBJECTIVE: To describe the appearance and occurrence of abnormalities in the levator ani muscle seen on magnetic resonance imaging (MRI) in nulliparous women and in women after their first vaginal birth. METHODS: Multiplanar proton density magnetic resonance images were obtained at 0.5‐cm intervals from 80 nulliparous and 160 vaginally primiparous women. These had been previously obtained in a study of stress incontinence, and half the primiparas had stress incontinence. All scans were reviewed independently by at least two examiners blinded to parity and continence status. RESULTS: No levator ani defects were identified in nulliparous women. Thirty‐two primiparous women (20%) had a visible defect in the levator ani muscle. Defects were identified in the pubovisceral portion of the levator ani in 29 women and in the iliococcygeal portion in three women. Within the pubovisceral muscle, both unilateral and bilateral defects were found. The extent of abnormality varied from one individual to the next. Of the 32 women with defects, 23 (71%) were in the stress incontinent group. CONCLUSION: Abnormalities in the levator ani muscle are present on MRI after a vaginal delivery but are not found in nulliparas. (Obstet Gynecol 2003;101:46‐53.

Comparison of levator ani muscle defects and function in women with and without pelvic organ prolapse.

BACKGROUND: To compare levator ani defects and pelvic floor function among women with prolapse and controls. METHODS: Levator ani structure and function were measured in a case–control study with group matching for age, race, and hysterectomy status among 151 women with prolapse (cases) and 135 controls with normal support (controls) determined by pelvic organ prolapse quantification examination. Magnetic resonance imaging was used to determine whether there were “major” (more than half missing), “minor” (less than half of the muscle missing), or no defects in the levator ani muscles. Vaginal closure force at rest and during maximal pelvic muscle contraction was measured with an instrumented vaginal speculum. RESULTS: Cases were more likely to have major levator ani defects than controls (55% compared with 16%), with an adjusted odds ratio of 7.3 (95% confidence interval 3.9–13.6, P<.001) but equally likely to have minor defects (16% compared with 22%). Of women who reported delivery by forceps, 53% had major defects compared with 28% for the nonforceps women, adjusted odds ratio 3.4 (95% confidence interval 1.95–5.78). Women with prolapse generated less vaginal closure force during pelvic muscle contraction than controls (2.0 Newtons compared with 3.2 Newtons P<.001), whereas those with defects generated less force than women without defects (2.0 Newtons compared with 3.1 Newtons, P<.001). The genital hiatus was 50% longer in cases than controls (4.7±1.4 cm compared with 3.1±1.0 cm, P<.001). CONCLUSION: Women with prolapse more often have defects in the levator ani and generate less vaginal closure force during a maximal contraction than controls. LEVEL OF EVIDENCE: II

Obstetric factors associated with levator ani muscle injury after vaginal birth.

OBJECTIVE: To identify obstetric factors associated with development of levator ani injury after vaginal birth. METHODS: Magnetic resonance images were taken of the pelvic floor of 160 women 9 to 12 months after first term vaginal delivery. Half the women had de novo stress incontinence and half were continent controls. Abnormalities of the pubovisceral portion were identified on magnetic resonance as present or absent. Defect severity was further scored in each muscle from 0 (no defect) to 3 (complete muscle loss). A summed score for the 2 sides (0 to 6) was assigned and grouped as minor (0–3) or major (4–6). Obstetric details were collected. The association between obstetric variables and muscle injury were analyzed using Fisher exact test and t tests. RESULTS: The following increased odds ratios for levator defect were found: forceps use 14.7 (95% confidence interval [CI] 4.9–44.3), anal sphincter rupture 8.1 (95% CI 3.3–19.5) and episiotomy 3.1 (95% CI 1.4–7.2) but not vacuum delivery 0.9 (95% CI 0.19–4.3), epidural use 0.9 (95% CI 0.4–2.0), or oxytocin use 0.8 (95% CI 0.3–1.8). Women with levator injury were 3.5 years older and had a 78-minute longer second stage of labor. Differences in gestational age, birth weight, and head circumference were not statistically significant. A major defect in the pubovisceral muscle was seen in 22 women and a minor defect in 7 women. CONCLUSION: Injuries to the levator ani muscles in women after their first vaginal delivery are associated with several obstetric factors indicating difficult vaginal birth and with older age. LEVEL OF EVIDENCE: II-3

Levator Ani Muscle Anatomy Evaluated by Origin-Insertion Pairs

OBJECTIVE: To examine the published literature and suggest a resolution to the confusion that exists in levator ani muscle descriptions and terminology. DATA SOURCES: A MEDLINE search was performed using the keyword “levator ani,” limited to human studies in women. References found in these articles were reviewed to identify research reported before 1966 and articles not included in the search. STUDY SELECTION: Studies were accepted if they contained direct observations of female specimens. Only those that contained specific descriptions or illustrations of the muscle origins and insertions in more than 5 female specimens were included. Review of 265 human studies yielded 9 qualifying articles, and reference tracing disclosed 3 additional reports. TABULATION, INTEGRATION, AND RESULTS: The literature review identified 5 origin-insertion pairs consistently described in studies directly examining the levator ani muscle in women, but 16 terms were used by authors for these 5 components of the muscle. Labeled illustrations often provided more precise information than was provided in the text. Terms were reviewed for inconsistencies of usage and appropriateness of term choice. The terms puboperineal, pubovaginal, and puboanal (for components of the pubovisceral [“pubococcygeal”] muscle), along with puborectal and iliococcygeal, are sufficient to describe the divisions of the levator ani muscle. CONCLUSION: Although there was great diversity and conflict in terms chosen among the original articles, the number of origin and insertion pairs was relatively consistent among authors and confusion can be avoided by standardizing terminology. LEVEL OF EVIDENCE: III

Appearance of the Levator Ani Muscle Subdivisions in Magnetic Resonance Images

OBJECTIVE: Identify and describe the separate appearance of 5 levator ani muscle subdivisions seen in axial, coronal, and sagittal magnetic resonance imaging (MRI) scan planes. METHODS: Magnetic resonance scans of 80 nulliparous women with normal pelvic support were evaluated. Characteristic features of each Terminologia Anatomica–listed levator ani component were determined for each scan plane. Muscle component visibility was based on pre-established criteria in axial, coronal, and sagittal scan planes: 1) clear and consistently visible separation or 2) different origin or insertion. Visibility of each of the levator ani subdivisions in each scan plane was assessed in 25 nulliparous women. RESULTS: In the axial plane, the puborectal muscle can be seen lateral to the pubovisceral muscle and decussating dorsal to the rectum. The course of the puboperineal muscle near the perineal body is visualized in the axial plane. The coronal view is perpendicular to the fiber direction of the puborectal and pubovisceral muscles and shows them as “clusters” of muscle on either side of the vagina. The sagittal plane consistently demonstrates the puborectal muscle passing dorsal to the rectum to form a sling that can consistently be seen as a “bump.” This plane is also parallel to the pubovisceral muscle fiber direction and shows the puboperineal muscle. CONCLUSION: The subdivisions of the levator ani muscle are visible in MRI scans, each with distinct morphology and characteristic features. LEVEL OF EVIDENCE: III

Vaginal birth and de novo stress incontinence: Relative contributions of urethral dysfunction and mobility

OBJECTIVE: To evaluate the relative contributions of urethral mobility and urethral function to stress incontinence. METHODS: This was a case-control study with group matching. Eighty primiparous women with self-reported new stress incontinence 9–12 months postpartum were compared with 80 primiparous continent controls to identify impairments specific to stress incontinence. Eighty nulliparous continent controls were evaluated as a comparison group to allow us to determine birth-related changes not associated with stress incontinence. Urethral function was measured with urethral profilometry, and vesical neck mobility was assessed with ultrasound and cotton swab test. Urethral sphincter anatomy and mobility were evaluated using magnetic resonance imaging. The associations among urethral closure pressure, vesical neck movement, and incontinence were explored using logistic regression. RESULTS: Urethral closure pressure (±standard deviation) in primiparous incontinent women (62.9±25.2 cm H20) was lower than in primiparous continent women (83.9±21.0, P<.001; effect size d=0.91) who were similar to nulliparous women (90.3±25.0, P=.091). Vesical neck movement measured during cough with ultrasonography was the mobility measure most associated with stress incontinence; 15.6±6.2 mm in incontinent women compared with 10.9±6.2 in primiparous continent women (P<.001, d=0.76) or nulliparas (9.9±5.0, P=.322). Logistic regression disclosed the two-variable model (max-rescaled R2=0.37, P<.001) was more strongly associated with stress incontinence than either single-variable model, urethral closure pressure (R2=0.25, P<.001) or vesical neck movement (R2=0.16 P<.001). CONCLUSION: Lower maximal urethral closure pressure is the measure most associated with de novo stress incontinence after first vaginal birth followed by vesical neck mobility. LEVEL OF EVIDENCE: II

Levator ani injury in primiparous women with forceps delivery for fetal distress, forceps for second stage arrest, and spontaneous delivery

To compare levator ani muscle injury rates in primiparous women who had a forceps delivery owing to fetal distress with women delivered by forceps for second stage arrest; and to compare these injury rates with a historical control group of women who delivered spontaneously.

Selecting suspension points and excising the vagina during michigan four-wall sacrospinous suspension

Abstract Objective To describe the variations in the location of the vaginal apex and the length of vagina excised in women undergoing the Michigan four-wall sacrospinous suspension for posthysterectomy vaginal vault prolapse. Methods A prospective observational study of 76 women who had the Michigan modification sacrospinous suspension performed between 1998 and 2001 for posthysterectomy vaginal vault prolapse was carried out. Demographics and preoperative, operative, and postoperative findings were noted, including the pelvic organ prolapse quantification score. The locations of the suspension points relative to the hysterectomy scar were recorded. The amount of vagina excised at surgery and the pre- and postoperative vaginal lengths are reported. Results The mean length and standard deviation of vagina excised was 4.6 ± 2.5 cm. The apex created at sacrospinous fixation was at the hysterectomy scar in only seven women (9%). It was most often situated behind the hysterectomy scar, in 58 cases (76%); it was situated in front of it in 11 (14%). In seven women no vagina was excised, and in the remaining 69 women a mean length of 5.1 ± 2.2 cm was removed. The mean vaginal lengths were 9.7 ± 1.7 cm preoperatively and 9.4 cm ± 0.8 postoperatively, a 0.3-cm difference. Conclusion When one performs the Michigan modification sacrospinous suspension, the chosen suspension points are often not at the hysterectomy scar, and in women with large prolapses excess vagina frequently is excised without compromising postoperative vaginal length.

Self-management of vaginal pessaries for pelvic organ prolapse

Two thirds of women opt to use a vaginal pessary initially to manage the symptoms of pelvic organ prolapse. In the UK most women attend a health care professional at least every six months to change the pessary. This represents a significant burden both economically to the health care system and personally for the woman. Annually there are more than 300 appointments for pessary changes at our hospital. We developed a programme to teach women to self-manage their pessaries with the aim of improving patient experience and reducing outpatient attendances to free up outpatient capacity for new referrals. A physiotherapist was recuited to deliver this programme involving a one to one training session supplemented with written materials and an online video. Women using pessaries were offered the option of self-management. Eighty-eight women aged between 29 to 84 years enrolled in the programme. Sixty-three women (73% of those enrolled) successfully continued with self-management at six months, creating 126 extra outpatient appointment capacity in one year alone. Women self-managing reported higher levels of convenience (94% vs 81%), accessibility (97% vs 73%), support (100% vs. 83%), and comfort (86% vs. 53%) than those attending the hospital for GP practice for pessary change. Self-management appears to be an acceptable option for many women using vaginal pessaries, with personal benefits to the women and economic benefits to the hospital and commissioners.

Comparison of levator ani muscle defects and function in women with and without pelvic organ prolapse

The levator ani muscles are critical for providing upward support to the pelvic organs and minimizing the load on the connective tissue that attaches these organs to the pelvis. When the muscles fail, pelvic organ prolapse may ensue, making surgery necessary. Vaginal birth substantially increases the risk of prolapse in occurring in parous women, but it is not clear whether levator ani defects lead to prolapse later in life. The possibility that this may be the case has lent support to cesarean delivery on request. This case-control study compared the structure and function of the levator ani muscle in 151 women with prolapse and 135 control subjects matched for age, race, and hysterectomy status. Case patients had prolapse of a vaginal wall, a hysterectomy scar, or the cervix extending at least 1 cm above the hymen during a Valsalva maneuver. MR imaging served to identify major defects with more than half the levator ani missing, and minor defects with less than half the muscle missing. An instrumented vaginal speculum was used to quantify vaginal closure force at rest and during maximum pelvic muscle contraction. The incidence of major levator ani defects was 55% in cases and 16% in controls, for an adjusted odds ratio (OR) of 7.3 (95% confidence interval [CI], 3.9-13.6). Women in the two groups were, however, about equally likely to have minor defects. Incidence rates of major defects were 53% for women reporting having had a forceps delivery and 28% for the others (adjusted OR, 3.4; 95% CI, 1.95-5.78). Women with prolapse had lower estimates of vaginal closure force during pelvic muscle contraction than did control subjects (2.0 versus 3.2 Newtons). Women with levator ani defects generated less force than those lacking defects (2.0 versus 3.1 Newtons). The genital hiatus was 50% longer in case women than in controls (4.7 versus 3.1 cm). In both the case and control groups, women without levator ani defects had higher maximal contraction force estimates than those with defects. This case-control study showed that women having pelvic organ prolapse more often have defective levator ani muscles than control women, and generate less vaginal closure force during maximal muscle contraction.