Ultrasound Obstet Gynecol 2014; 44: 700–703 Published online 6 November 2014 in Wiley Online Library (wileyonlinelibrary.com). DOI: 10.1002/uog.13325
Sonographic finding of postpartum levator ani muscle injury correlates with pelvic floor clinical examination M. LIPSCHUETZ*, D. V. VALSKY*, L. SHICK-NAVEH†, H. DAUM*, B. MESSING*, I. YAGEL*, S. YAGEL* and S. M. COHEN* *Division of Obstetrics and Gynecology, Hadassah-Hebrew University Medical Centers, Jerusalem, Israel; †Department of Physiotherapy, Hadassah-Hebrew University Medical Center, Mt. Scopus, Jerusalem, Israel
K E Y W O R D S: 3D-TPS; levator ani; pelvic floor; primiparae
ABSTRACT
INTRODUCTION
Objectives Correlation of the sonographic finding of levator ani muscle (LAM) injuries with clinical examination in primiparous women following vaginal delivery has not been fully described. We aimed to examine the correlation of three-dimensional transperineal ultrasound (3D-TPS) finding of LAM defects with results of clinical examination of the pelvic floor, at intermediate follow-up.
In recent years, the effects of parturition on the female pelvic floor have been the focus of intensive research. The pelvic floor is classically divided into two compartments: the posterior and the anterior. When trauma occurs in the posterior compartment (i.e. a tear to the muscles of the anal sphincter complex)1 , the damage is usually apparent clinically and can be imaged using ultrasound or magnetic resonance (MR)2 – 4 , although occult trauma has also been described1,4 . In the case of the anterior compartment, the situation differs. Levator ani muscle (LAM) injury is rarely visible clinically, apparent only in some cases of levator ani avulsion5 or separation from the anteromedial part of the symphysis pubis. LAM injury has been described as the ‘missing link’ between trauma during parturition and pelvic floor dysfunction, which is usually recognized only years later. The lesion is mainly defined by its imaging appearance, whether by ultrasound5 – 8 or MR9,10 . Over the years, correlations between the appearance of clinical and imaging findings of disordered pelvic floor function have been investigated2,8 – 14 . Some of these studies focused on women presenting to urogynecology clinics with complaints such as urinary incontinence or uterine prolapse11,12 or immediately following labor and delivery with known trauma to the posterior compartment9 . Correlation of sonographic appearance of LAM injuries with clinical examination, in an unselected cohort of women several months following primary vaginal delivery who were not referred for pelvic floor complaints, has not been fully described. Pelvic floor disorder complaints after childbirth have been widely described15 – 19 , particularly complaints of urinary incontinence. The prevalence of such complaints among primiparous women is estimated at 13–40%20 . Despite the prevalence of pelvic floor disorders there are few objective tools to examine this phenomenon. The correlation of ultrasound findings of LAM defects and physical examination may add to our overall understanding of
Methods Subjects were primiparae 3–21 months following vaginal delivery, who had not become pregnant or delivered in the interim. On 3D-TPS, LAM trauma was diagnosed when discontinuity and distortion were visible in the most anteromedial part of the pubovisceral muscle in the coronal C-plane or rendered image. Clinical examination was performed by a physiotherapist who was blinded to the ultrasound results, and included palpation of the medial and lateral parts of the LAM mass, evaluation of tissue quality and whether there was any palpable gap. Muscle strength was evaluated using the modified Oxford scale. Results Eighty-seven women were included, 19 (21.8%) of whom were found to have a sonographic LAM injury. Oxford score palpation parameter of asymmetric muscle mass or texture was significantly correlated with the finding of a LAM defect: of 68 women with normal 3D-TPS, 22 (32.4%) were found to have asymmetry of muscle mass or tissue quality on clinical examination vs 12 (63.2%) of 19 women with sonographic evidence of LAM injury (P = 0.016). Muscle strength and endurance parameters did not significantly correlate with the 3D-TPS findings. Conclusion Our findings suggest that persistent 3D-TPS LAM injury after primary vaginal delivery has clinical expression in changes in mass and texture of the LAM, as assessed by palpation. Copyright © 2014 ISUOG. Published by John Wiley & Sons Ltd.
Correspondence to: Ms S. M. Cohen, Division of Obstetrics and Gynecology, Hadassah-Hebrew University Medical Centers, Mt. Scopus, Jerusalem 91240, Israel (e-mail: [email protected]) Accepted: 28 January 2014
Copyright © 2014 ISUOG. Published by John Wiley & Sons Ltd.
ORIGINAL PAPER
Sonographic LAM injury correlates with clinical examination pelvic floor disorders in later life and why some women develop problems whereas others do not. In populations of women presenting to urogynecology clinics with complaints of pelvic organ prolapse, several studies of LAM clinical assessment have been performed11,12,21 – 23 . Dietz and colleagues developed a digital examination to palpate levator ani disruption11,12,21,22 and compared this clinical finding with both translabial two-dimensional (2D)11,22 and three/four dimensional (3D/4D)12,21 sonography, as well as squeeze pressure, as measured by perineometry11 , and signs and symptoms of pelvic organ prolapse11,12 . The authors compared interobserver agreement of the clinical examination, and digital examination with sonographic findings11,12,21,22 , and found that with training a high degree of accuracy can be achieved22 . We aimed to determine whether the 3D transperineal ultrasound (3D-TPS) appearance of the LAM defect correlated with results of clinical examination of the pelvic floor in women 3–24 months following primary vaginal delivery.
METHODS The Institutional Review Board of Hadassah-Hebrew University Medical Centers approved the study; all patients signed informed consent and were seen at Hadassah. We invited participants from a previous study7 to attend for 3D-TPS pelvic floor follow-up evaluation. Follow-up for the present study included 3D-TPS combined with clinical examination of the pelvic floor according to the modified Oxford scale. Women who were pregnant at the time of contact, or had given birth in the interim since the earlier study, were excluded. 3D-TPS examination was performed by a consultant in obstetrics and gynecology with particular expertise in 3D-TPS who was blinded to patients’ earlier results; clinical examination was performed by a physiotherapist with particular expertise in the female pelvic floor. 3D-TPS was performed as described previously6 – 8 . Briefly, with the patient in the lithotomy position and with an almost empty bladder, the covered transabdominal probe was placed in the area of the fourchette and perineal body. The transducer axis was oriented in the mid-sagittal plane, and the symphysis pubis, bladder neck and urethra, compressed vagina, distal part of the rectum with anorectal junction and the proximal part of the anal canal were imaged and a 3D ultrasound volume acquired. Post-processing was performed with the mid-sagittal plane in the ‘A’ frame of the multiplanar projection (MPR) screen; the pelvic hiatus was visualized on the coronal ‘C’ plane and in the rendered image. The structures visualized were the symphysis pubis with ramus pubis, urethra, vagina, the anal canal and the most superficial part of the levator ani–pubovisceral muscle, consisting of fibers of the vagina and the puborectalis and pubococcygeus muscles. Tomographic ultrasound images (TUI) of the volumes were also analyzed to exclude or confirm defects on successive planes.
Copyright © 2014 ISUOG. Published by John Wiley & Sons Ltd.
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Figure 1 Rendered image of pelvic floor 14 months postpartum, showing the levator ani muscle defect (circle).
LAM trauma was diagnosed when discontinuity and distortion were visible in the most anteromedial part of the pubovisceral muscle in the coronal C-plane or rendered image (Figure 1). This sonographic defect should be visible after symmetric adjustment of the image in the coronal plane and should be confirmed on the TUI image on at least three successive planes. The thickness of the LAM was not measured. Clinical examination was performed by a physiotherapist with specific training and expertise in the female pelvic floor, who was blinded to the results of the ultrasound examination. Examination was carried out with the patient in the lithotomy position and included several steps. First, the overall appearance of the perineum was evaluated and the presence of any scars was noted. Second, the woman was asked to cough and whether she contracted the pelvic floor muscles before coughing was visually observed. Third, the pelvic floor was palpated to evaluate muscle mass, tissue quality and whether there was any sign of gap or asymmetry. The index finger was applied at a 6 o’clock position to a depth of 3 cm to examine the medial portion of the LAM (the puborectalis) and between 3 to 5 o’clock and 7 to 9 o’clock to examine the lateral parts (the pubococcygeus and the iliococcygeus muscles). Fourth, muscle strength was assessed according to the modified Oxford scale proposed by Laycock3 . The index finger was introduced into the vagina and the degree of muscle contraction was rated on a scale of 0–5, as follows: 0, no palpable movement; 1, flicker; 2, weak (palpable movement in the muscle without elevation); 3, moderate (elevation of the walls of the vagina and muscle mass); 4, good (palpable tension of the muscle, elevation of the vaginal walls against resistance of the examiner’s digit); 5, strong (elevation of the vaginal walls against strong resistance of the examiner’s digit), repeating the contraction six times. Finally, the patients were asked to
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contract the pelvic floor muscles to maximum contraction and to maintain this for as long as they could, then they were allowed to rest for the same length of time. The duration of maximum contraction (in seconds) was recorded. The examiner palpated the pelvic floor muscles to verify that the contraction was produced in the expected area, or was produced by activation of other muscles. The examiner visually verified that the contraction of the pelvic floor was achieved without involvement of the transversus abdominis, hip adductors, or glutei. Activation of adjutant muscles and decrease in the strength of contraction were signs of muscle fatigue, and at this point the subject was asked to rest. In any case, when the subject held her breath she was requested to exhale, or asked to count audibly. Data collection and analysis were performed with SPSS v.15 (Chicago, IL, USA). Continuous variables were analyzed using ANOVA. Dichotomous variables were compared using the chi-square or Fisher’s exact tests, or the Eta statistic in the case of ordinal variables.
RESULTS Eighty-seven women examined in the postpartum period agreed to participate in the present study. Nineteen (21.8%) women had a sonographic finding of LAM defect. Background parameters of the study group are summarized in Table 1. No difference was observed on visual evaluation of the perineum between women with and those without LAM sonographic defects. Assessment of muscle tissue symmetry revealed asymmetry in 34 (39.1%) of the 87 women in the study group. Of those 34, a significantly higher proportion had sonographic evidence of LAM injury (P = 0.016) (Table 2). No significant difference was found between strength and endurance results of women with, compared with those without, a LAM defect (Table 2). Table 1 Background parameters of the study group Parameter
Value
Maternal age (years) GA at delivery (weeks) Interval since delivery (months) Duration of second stage (min) Fetal weight (g) Fetal head circumference (cm)
27.9 ± 5.1 (19–47) 39 + 3 ± 1.5 (32 + 1 to 42 + 0) 8.7 ± 3.5 (3–21) 77 ± 52 (2–251) 3203 ± 52.3 (1940–4080) 34.0 ± 1.2 (31.4–36.7)
Values are given as mean ± SD (range). GA, gestational age. Table 2 Comparison of clinical examination results in patients with normal vs abnormal three-dimensional transperineal ultrasound (US) levator ani muscle findings Parameter Asymmetry Strength (Oxf. scale 0–5) Endurance (s)
Normal US
Abnormal US
P
22/68 (32.4) 2.5 ± 1.0 (0–5)
12/19 (63.2) 2.5 ± 1.1 (1–4)
0.016* NS
6.4 ± 3.5 (1–10.5)
5.9 ± 3.9 (1–10)
NS
Values are given as n positive/total n (%) or mean ± SD (range). *Fisher’s exact test. NS, not significant; Oxf., Oxford.
Copyright © 2014 ISUOG. Published by John Wiley & Sons Ltd.
DISCUSSION In the present study we sought to investigate the possible correlation of sonographic findings of LAM defects in primiparous women following vaginal delivery with clinical examination of the pelvic floor at an intermediate follow-up period (i.e. neither immediately following birth nor only on the appearance of symptoms). Our findings suggest that 3D-TPS of the LAM is consistent with the finding of a levator defect observed during clinical examination. This was shown through the correlation between an ultrasound finding of the LAM defect, observed as sonographic drop-out in the LAM on 3D-TPS, and the finding of asymmetric muscle mass or texture on physical examination (P = 0.016). However, asymmetry, as recorded by the physiotherapist, did not always correlate with a sonographically demonstrable defect in the ultrasound image. Clues to understanding the observed lack of correlation between the strength and endurance parameters, which assess how strongly and for how long the patient can contract the pelvic floor, and sonographic findings of the levator ani defect, may be found in the muscle morphology. It is probable, in this circular structure made up of multiple fibers and connective tissue, that the presence of an isolated defect will not wholly prevent contraction. Furthermore, muscle strength is only one factor in contraction: insufficiency may result from many other factors that may impact on the pelvic floor, even in the absence of a LAM defect. Therefore, women without a 3D-TPS defect may experience clinical complaints, whereas others with defects may not. Several groups have examined the correlation between imaging and clinical findings of levator ani avulsion11 – 13,23 . Kearney and colleagues compared the findings on MR imaging and clinical examination, and found strong correlation between both23 . Dietz et al. assessed the sonographic appearance of contraction of the pelvic floor in a population of women of mixed age and parity presenting to a urogynecology clinic with complaints of pelvic floor dysfunction or prolapse. The investigators found that translabial sonography successfully imaged the changes in pelvic floor anatomy during contraction and that these changes correlated with digital palpation11 . In a later study, Dietz and colleagues found that the levator ani defect palpable on their examination was visualized on translabial 3D-TPS12 in a similarly mixed population. Among their patients they found that some 30% had a sonographically apparent levator ani injury12 . In contrast, our physical examination focused on the mass of the levator ani, as opposed to the method proposed by Dietz and colleagues, which focused on the muscle insertion12 . This may have impacted our results. We sought to correlate the results of 3D-TPS with parameters of the Oxford scale in primiparous women, specifically limiting our study to a homogeneous group of gravidae, evaluated relatively early following delivery, before another pregnancy and/or delivery intervened, in order to focus on the effects of first delivery on the pelvic floor. In studies based on mixed populations of vaginally
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Sonographic LAM injury correlates with clinical examination parous and nulliparous women presenting with clinical complaints11,12 , the effect of parturition could not be isolated. It has been shown that prenatal preventative interventions are effective in reducing pelvic floor problems postnatally24 – 26 . Women found to have evidence of levator ani defects may be at higher risk of developing pelvic floor problems later in life12 and may also benefit from exercises to strengthen and maintain this complex system24 – 26 . Our approach may help to identify high-risk women who may be referred for pelvic floor physiotherapy. Intrapartum management, focusing on modifiable risk factors in subsequent deliveries, such as a lengthy second stage in fetuses with a large head circumference, may help prevent development of symptoms of pelvic floor dysfunction. Our study has several strengths and limitations. Both the sonographer and the physiotherapist were blinded to results that may have influenced their examinations. We evaluated pelvic floor anatomy and function both sonographically and clinically. Our 3D-TPS approach is accessible (being more readily available and much less expensive than MR imaging, for example) and acceptable to patients. In addition, whilst the clinical pelvic floor examination is subjective, the modified Oxford scale3 is well recognized in clinical practice. We recognize the study’s limitations, such as small group size. When recruiting patients from our earlier study we found that many were pregnant or had delivered a second child. In conclusion, the 3D-TPS LAM defect correlates with palpable asymmetry of pelvic floor musculature in primiparous women.
REFERENCES 1. Sultan AH, Kamm MA, Hudson CN, Thomas JM, Bartram CI. Anal-sphincter disruption during vaginal delivery. N Engl J Med 1993; 329: 1905–1911. 2. Dietz HP. Pelvic floor trauma following vaginal delivery. Curr Opin Obstet Gynecol 2006; 18: 528–537. 3. Laycock J. Clinical evaluation of the pelvic floor. In Pelvic Floor Re-education: Principles and Practice, Schuessler B (ed). Springer: London, 1994; 42–48. 4. Valsky DV, Messing B, Petkova R, Savchev S, Rosenak D, Hochner-Celnikier D, Yagel S. Postpartum evaluation of the anal sphincter by transperineal three-dimensional ultrasound in primiparous women after vaginal delivery and following surgical repair of third-degree tears by the overlapping technique. Ultrasound Obstet Gynecol 2007; 29: 195–204. 5. Dietz HP, Lanzarone V. Levator trauma after vaginal delivery. Obstet Gynecol 2005; 106: 707–712. 6. Dietz HP. Ultrasound imaging of the pelvic floor. Part II: three-dimensional or volume imaging. Ultrasound Obstet Gynecol 2004; 23: 615–625. 7. Valsky DV, Lipschuetz M, Bord A, Eldar I, Messing B, Hochner-Celnikier D, Lavy Y, Cohen SM, Yagel S. Fetal head circumference and length of second stage of labor are risk factors for levator ani muscle injury, diagnosed by 3-dimensional transperineal ultrasound in primiparous women. Am J Obstet Gynecol 2009; 201: 91.e1–7. 8. Valsky DV, Yagel S. Three-dimensional transperineal ultrasonography of the pelvic floor: improving visualization for
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new clinical applications and better functional assessment. J Ultrasound Med 2007; 26: 1373–1387. Heilbrun ME, Nygaard IE, Lockhart ME, Richter HE, Brown MB, Kenton KS, Rahn DD, Thomas JV, Weidner AC, Nager CW, Delancey JO. Correlation between levator ani muscle injuries on magnetic resonance imaging and fecal incontinence, pelvic organ prolapse, and urinary incontinence in primiparous women. Am J Obstet Gynecol 2010; 202: 488.e1–6. Margulies RU, Hsu Y, Kearney R, Stein T, Umek WH, DeLancey JO. Appearance of the levator ani muscle subdivisions in magnetic resonance images. Obstet Gynecol 2006; 107: 1064–1069. Dietz HP, Jarvis SK, Vancaillie TG. The assessment of levator muscle strength: a validation of three ultrasound techniques. Int Urogynecol J Pelvic Floor Dysfunct 2002; 13: 156–159; discussion 159. Dietz HP, Moegni F, Shek KL. Diagnosis of levator avulsion injury: a comparison of three methods. Ultrasound Obstet Gynecol 2012; 40: 693–698. Dietz HP, Shek KL, Chantarasorn V, Langer SE. Do women notice the effect of childbirth-related pelvic floor trauma? Aust N Z J Obstet Gynaecol 2012; 52: 277–281. Weidner AC, Jamison MG, Branham V, South MM, Borawski KM, Romero AA. Neuropathic injury to the levator ani occurs in 1 in 4 primiparous women. Am J Obstet Gynecol 2006; 195: 1851–1856. DeLancey JO. The hidden epidemic of pelvic floor dysfunction: achievable goals for improved prevention and treatment. Am J Obstet Gynecol 2005; 192: 1488–1495. Lavy Y, Sand PK, Kaniel CI, Hochner-Celnikier D. Can pelvic floor injury secondary to delivery be prevented? Int Urogynecol J 2012; 23: 165–173. Kepenekci I, Keskinkilic B, Akinsu F, Cakir P, Elhan AH, Erkek AB, Kuzu MA. Prevalence of pelvic floor disorders in the female population and the impact of age, mode of delivery, and parity. Dis Colon Rectum 2011; 54: 85–94. Thom DH, Rortveit G. Prevalence of postpartum urinary incontinence: a systematic review. Acta Obstet Gynecol Scand 2010; 89: 1511–1522. Rortveit G, Daltveit AK, Hannestad YS, Hunskaar S. Vaginal delivery parameters and urinary incontinence: the Norwegian EPINCONT study. Am J Obstet Gynecol 2003; 189: 1268–1274. Thom DH, Rortveit G. Prevalence of postpartum urinary incontinence: a systematic review. Acta Obstet Gynecol Scand; 89: 1511–1522. Dietz HP, Hyland G, Hay-Smith J. The assessment of levator trauma: a comparison between palpation and 4D pelvic floor ultrasound. Neurourol Urodyn 2006; 25: 424–427. Dietz HP, Shek C. Validity and reproducibility of the digital detection of levator trauma. Int Urogynecol J Pelvic Floor Dysfunct 2008; 19: 1097–1101. Kearney R, Miller JM, Delancey JO. Interrater reliability and physical examination of the pubovisceral portion of the levator ani muscle, validity comparisons using MR imaging. Neurourol Urodyn 2006; 25: 50–54. Bo K. Pelvic floor muscle training is effective in treatment of female stress urinary incontinence, but how does it work? Int Urogynecol J Pelvic Floor Dysfunct 2004; 15: 76–84. Boyle R, Hay-Smith EJ, Cody JD, Morkved S. Pelvic floor muscle training for prevention and treatment of urinary and faecal incontinence in antenatal and postnatal women. Cochrane Database Syst Rev 2012; 10: CD007471. Kocaoz S, Eroglu K, Sivaslioglu AA. Role of pelvic floor muscle exercises in the prevention of stress urinary incontinence during pregnancy and the postpartum period. Gynecol Obstet Invest 2013; 75: 34–40.
Ultrasound Obstet Gynecol 2014; 44: 700–703.
Sonographic finding of postpartum levator ani muscle injury correlates with pelvic floor clinical examination M. LIPSCHUETZ*, D. V. VALSKY*, L. SHICK-NAVEH†, H. DAUM*, B. MESSING*, I. YAGEL*, S. YAGEL* and S. M. COHEN* *Division of Obstetrics and Gynecology, Hadassah-Hebrew University Medical Centers, Jerusalem, Israel; †Department of Physiotherapy, Hadassah-Hebrew University Medical Center, Mt. Scopus, Jerusalem, Israel
K E Y W O R D S: 3D-TPS; levator ani; pelvic floor; primiparae
ABSTRACT
INTRODUCTION
Objectives Correlation of the sonographic finding of levator ani muscle (LAM) injuries with clinical examination in primiparous women following vaginal delivery has not been fully described. We aimed to examine the correlation of three-dimensional transperineal ultrasound (3D-TPS) finding of LAM defects with results of clinical examination of the pelvic floor, at intermediate follow-up.
In recent years, the effects of parturition on the female pelvic floor have been the focus of intensive research. The pelvic floor is classically divided into two compartments: the posterior and the anterior. When trauma occurs in the posterior compartment (i.e. a tear to the muscles of the anal sphincter complex)1 , the damage is usually apparent clinically and can be imaged using ultrasound or magnetic resonance (MR)2 – 4 , although occult trauma has also been described1,4 . In the case of the anterior compartment, the situation differs. Levator ani muscle (LAM) injury is rarely visible clinically, apparent only in some cases of levator ani avulsion5 or separation from the anteromedial part of the symphysis pubis. LAM injury has been described as the ‘missing link’ between trauma during parturition and pelvic floor dysfunction, which is usually recognized only years later. The lesion is mainly defined by its imaging appearance, whether by ultrasound5 – 8 or MR9,10 . Over the years, correlations between the appearance of clinical and imaging findings of disordered pelvic floor function have been investigated2,8 – 14 . Some of these studies focused on women presenting to urogynecology clinics with complaints such as urinary incontinence or uterine prolapse11,12 or immediately following labor and delivery with known trauma to the posterior compartment9 . Correlation of sonographic appearance of LAM injuries with clinical examination, in an unselected cohort of women several months following primary vaginal delivery who were not referred for pelvic floor complaints, has not been fully described. Pelvic floor disorder complaints after childbirth have been widely described15 – 19 , particularly complaints of urinary incontinence. The prevalence of such complaints among primiparous women is estimated at 13–40%20 . Despite the prevalence of pelvic floor disorders there are few objective tools to examine this phenomenon. The correlation of ultrasound findings of LAM defects and physical examination may add to our overall understanding of
Methods Subjects were primiparae 3–21 months following vaginal delivery, who had not become pregnant or delivered in the interim. On 3D-TPS, LAM trauma was diagnosed when discontinuity and distortion were visible in the most anteromedial part of the pubovisceral muscle in the coronal C-plane or rendered image. Clinical examination was performed by a physiotherapist who was blinded to the ultrasound results, and included palpation of the medial and lateral parts of the LAM mass, evaluation of tissue quality and whether there was any palpable gap. Muscle strength was evaluated using the modified Oxford scale. Results Eighty-seven women were included, 19 (21.8%) of whom were found to have a sonographic LAM injury. Oxford score palpation parameter of asymmetric muscle mass or texture was significantly correlated with the finding of a LAM defect: of 68 women with normal 3D-TPS, 22 (32.4%) were found to have asymmetry of muscle mass or tissue quality on clinical examination vs 12 (63.2%) of 19 women with sonographic evidence of LAM injury (P = 0.016). Muscle strength and endurance parameters did not significantly correlate with the 3D-TPS findings. Conclusion Our findings suggest that persistent 3D-TPS LAM injury after primary vaginal delivery has clinical expression in changes in mass and texture of the LAM, as assessed by palpation. Copyright © 2014 ISUOG. Published by John Wiley & Sons Ltd.
Correspondence to: Ms S. M. Cohen, Division of Obstetrics and Gynecology, Hadassah-Hebrew University Medical Centers, Mt. Scopus, Jerusalem 91240, Israel (e-mail: [email protected]) Accepted: 28 January 2014
Copyright © 2014 ISUOG. Published by John Wiley & Sons Ltd.
ORIGINAL PAPER
Sonographic LAM injury correlates with clinical examination pelvic floor disorders in later life and why some women develop problems whereas others do not. In populations of women presenting to urogynecology clinics with complaints of pelvic organ prolapse, several studies of LAM clinical assessment have been performed11,12,21 – 23 . Dietz and colleagues developed a digital examination to palpate levator ani disruption11,12,21,22 and compared this clinical finding with both translabial two-dimensional (2D)11,22 and three/four dimensional (3D/4D)12,21 sonography, as well as squeeze pressure, as measured by perineometry11 , and signs and symptoms of pelvic organ prolapse11,12 . The authors compared interobserver agreement of the clinical examination, and digital examination with sonographic findings11,12,21,22 , and found that with training a high degree of accuracy can be achieved22 . We aimed to determine whether the 3D transperineal ultrasound (3D-TPS) appearance of the LAM defect correlated with results of clinical examination of the pelvic floor in women 3–24 months following primary vaginal delivery.
METHODS The Institutional Review Board of Hadassah-Hebrew University Medical Centers approved the study; all patients signed informed consent and were seen at Hadassah. We invited participants from a previous study7 to attend for 3D-TPS pelvic floor follow-up evaluation. Follow-up for the present study included 3D-TPS combined with clinical examination of the pelvic floor according to the modified Oxford scale. Women who were pregnant at the time of contact, or had given birth in the interim since the earlier study, were excluded. 3D-TPS examination was performed by a consultant in obstetrics and gynecology with particular expertise in 3D-TPS who was blinded to patients’ earlier results; clinical examination was performed by a physiotherapist with particular expertise in the female pelvic floor. 3D-TPS was performed as described previously6 – 8 . Briefly, with the patient in the lithotomy position and with an almost empty bladder, the covered transabdominal probe was placed in the area of the fourchette and perineal body. The transducer axis was oriented in the mid-sagittal plane, and the symphysis pubis, bladder neck and urethra, compressed vagina, distal part of the rectum with anorectal junction and the proximal part of the anal canal were imaged and a 3D ultrasound volume acquired. Post-processing was performed with the mid-sagittal plane in the ‘A’ frame of the multiplanar projection (MPR) screen; the pelvic hiatus was visualized on the coronal ‘C’ plane and in the rendered image. The structures visualized were the symphysis pubis with ramus pubis, urethra, vagina, the anal canal and the most superficial part of the levator ani–pubovisceral muscle, consisting of fibers of the vagina and the puborectalis and pubococcygeus muscles. Tomographic ultrasound images (TUI) of the volumes were also analyzed to exclude or confirm defects on successive planes.
Copyright © 2014 ISUOG. Published by John Wiley & Sons Ltd.
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Figure 1 Rendered image of pelvic floor 14 months postpartum, showing the levator ani muscle defect (circle).
LAM trauma was diagnosed when discontinuity and distortion were visible in the most anteromedial part of the pubovisceral muscle in the coronal C-plane or rendered image (Figure 1). This sonographic defect should be visible after symmetric adjustment of the image in the coronal plane and should be confirmed on the TUI image on at least three successive planes. The thickness of the LAM was not measured. Clinical examination was performed by a physiotherapist with specific training and expertise in the female pelvic floor, who was blinded to the results of the ultrasound examination. Examination was carried out with the patient in the lithotomy position and included several steps. First, the overall appearance of the perineum was evaluated and the presence of any scars was noted. Second, the woman was asked to cough and whether she contracted the pelvic floor muscles before coughing was visually observed. Third, the pelvic floor was palpated to evaluate muscle mass, tissue quality and whether there was any sign of gap or asymmetry. The index finger was applied at a 6 o’clock position to a depth of 3 cm to examine the medial portion of the LAM (the puborectalis) and between 3 to 5 o’clock and 7 to 9 o’clock to examine the lateral parts (the pubococcygeus and the iliococcygeus muscles). Fourth, muscle strength was assessed according to the modified Oxford scale proposed by Laycock3 . The index finger was introduced into the vagina and the degree of muscle contraction was rated on a scale of 0–5, as follows: 0, no palpable movement; 1, flicker; 2, weak (palpable movement in the muscle without elevation); 3, moderate (elevation of the walls of the vagina and muscle mass); 4, good (palpable tension of the muscle, elevation of the vaginal walls against resistance of the examiner’s digit); 5, strong (elevation of the vaginal walls against strong resistance of the examiner’s digit), repeating the contraction six times. Finally, the patients were asked to
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contract the pelvic floor muscles to maximum contraction and to maintain this for as long as they could, then they were allowed to rest for the same length of time. The duration of maximum contraction (in seconds) was recorded. The examiner palpated the pelvic floor muscles to verify that the contraction was produced in the expected area, or was produced by activation of other muscles. The examiner visually verified that the contraction of the pelvic floor was achieved without involvement of the transversus abdominis, hip adductors, or glutei. Activation of adjutant muscles and decrease in the strength of contraction were signs of muscle fatigue, and at this point the subject was asked to rest. In any case, when the subject held her breath she was requested to exhale, or asked to count audibly. Data collection and analysis were performed with SPSS v.15 (Chicago, IL, USA). Continuous variables were analyzed using ANOVA. Dichotomous variables were compared using the chi-square or Fisher’s exact tests, or the Eta statistic in the case of ordinal variables.
RESULTS Eighty-seven women examined in the postpartum period agreed to participate in the present study. Nineteen (21.8%) women had a sonographic finding of LAM defect. Background parameters of the study group are summarized in Table 1. No difference was observed on visual evaluation of the perineum between women with and those without LAM sonographic defects. Assessment of muscle tissue symmetry revealed asymmetry in 34 (39.1%) of the 87 women in the study group. Of those 34, a significantly higher proportion had sonographic evidence of LAM injury (P = 0.016) (Table 2). No significant difference was found between strength and endurance results of women with, compared with those without, a LAM defect (Table 2). Table 1 Background parameters of the study group Parameter
Value
Maternal age (years) GA at delivery (weeks) Interval since delivery (months) Duration of second stage (min) Fetal weight (g) Fetal head circumference (cm)
27.9 ± 5.1 (19–47) 39 + 3 ± 1.5 (32 + 1 to 42 + 0) 8.7 ± 3.5 (3–21) 77 ± 52 (2–251) 3203 ± 52.3 (1940–4080) 34.0 ± 1.2 (31.4–36.7)
Values are given as mean ± SD (range). GA, gestational age. Table 2 Comparison of clinical examination results in patients with normal vs abnormal three-dimensional transperineal ultrasound (US) levator ani muscle findings Parameter Asymmetry Strength (Oxf. scale 0–5) Endurance (s)
Normal US
Abnormal US
P
22/68 (32.4) 2.5 ± 1.0 (0–5)
12/19 (63.2) 2.5 ± 1.1 (1–4)
0.016* NS
6.4 ± 3.5 (1–10.5)
5.9 ± 3.9 (1–10)
NS
Values are given as n positive/total n (%) or mean ± SD (range). *Fisher’s exact test. NS, not significant; Oxf., Oxford.
Copyright © 2014 ISUOG. Published by John Wiley & Sons Ltd.
DISCUSSION In the present study we sought to investigate the possible correlation of sonographic findings of LAM defects in primiparous women following vaginal delivery with clinical examination of the pelvic floor at an intermediate follow-up period (i.e. neither immediately following birth nor only on the appearance of symptoms). Our findings suggest that 3D-TPS of the LAM is consistent with the finding of a levator defect observed during clinical examination. This was shown through the correlation between an ultrasound finding of the LAM defect, observed as sonographic drop-out in the LAM on 3D-TPS, and the finding of asymmetric muscle mass or texture on physical examination (P = 0.016). However, asymmetry, as recorded by the physiotherapist, did not always correlate with a sonographically demonstrable defect in the ultrasound image. Clues to understanding the observed lack of correlation between the strength and endurance parameters, which assess how strongly and for how long the patient can contract the pelvic floor, and sonographic findings of the levator ani defect, may be found in the muscle morphology. It is probable, in this circular structure made up of multiple fibers and connective tissue, that the presence of an isolated defect will not wholly prevent contraction. Furthermore, muscle strength is only one factor in contraction: insufficiency may result from many other factors that may impact on the pelvic floor, even in the absence of a LAM defect. Therefore, women without a 3D-TPS defect may experience clinical complaints, whereas others with defects may not. Several groups have examined the correlation between imaging and clinical findings of levator ani avulsion11 – 13,23 . Kearney and colleagues compared the findings on MR imaging and clinical examination, and found strong correlation between both23 . Dietz et al. assessed the sonographic appearance of contraction of the pelvic floor in a population of women of mixed age and parity presenting to a urogynecology clinic with complaints of pelvic floor dysfunction or prolapse. The investigators found that translabial sonography successfully imaged the changes in pelvic floor anatomy during contraction and that these changes correlated with digital palpation11 . In a later study, Dietz and colleagues found that the levator ani defect palpable on their examination was visualized on translabial 3D-TPS12 in a similarly mixed population. Among their patients they found that some 30% had a sonographically apparent levator ani injury12 . In contrast, our physical examination focused on the mass of the levator ani, as opposed to the method proposed by Dietz and colleagues, which focused on the muscle insertion12 . This may have impacted our results. We sought to correlate the results of 3D-TPS with parameters of the Oxford scale in primiparous women, specifically limiting our study to a homogeneous group of gravidae, evaluated relatively early following delivery, before another pregnancy and/or delivery intervened, in order to focus on the effects of first delivery on the pelvic floor. In studies based on mixed populations of vaginally
Ultrasound Obstet Gynecol 2014; 44: 700–703.
Sonographic LAM injury correlates with clinical examination parous and nulliparous women presenting with clinical complaints11,12 , the effect of parturition could not be isolated. It has been shown that prenatal preventative interventions are effective in reducing pelvic floor problems postnatally24 – 26 . Women found to have evidence of levator ani defects may be at higher risk of developing pelvic floor problems later in life12 and may also benefit from exercises to strengthen and maintain this complex system24 – 26 . Our approach may help to identify high-risk women who may be referred for pelvic floor physiotherapy. Intrapartum management, focusing on modifiable risk factors in subsequent deliveries, such as a lengthy second stage in fetuses with a large head circumference, may help prevent development of symptoms of pelvic floor dysfunction. Our study has several strengths and limitations. Both the sonographer and the physiotherapist were blinded to results that may have influenced their examinations. We evaluated pelvic floor anatomy and function both sonographically and clinically. Our 3D-TPS approach is accessible (being more readily available and much less expensive than MR imaging, for example) and acceptable to patients. In addition, whilst the clinical pelvic floor examination is subjective, the modified Oxford scale3 is well recognized in clinical practice. We recognize the study’s limitations, such as small group size. When recruiting patients from our earlier study we found that many were pregnant or had delivered a second child. In conclusion, the 3D-TPS LAM defect correlates with palpable asymmetry of pelvic floor musculature in primiparous women.
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