Obstetric levator ani muscle injuries: Current status

Ultrasound in Obstetrics and Gynecology

Volumn 39, Issue 4, 2012, Pages 372-383

  Schwertner Tiepelmann, N ^a   Thakar, R ^a   Sultan, A H ^a   Tunn, R ^b  

^a MAYDAY UNIVERSITY HOSPITAL   (United Kingdom)

^b St Hedwig Hospital   (Germany)

Author keywords

childbirth; fecal incontinence; levator ani muscle avulsion; levator ani muscle injury; levator ani muscle trauma; pelvic floor trauma; pelvic organ prolapse; stress urinary incontinence

Indexed keywords

ADULT; DELIVERY; ECHOGRAPHY; FECES INCONTINENCE; FEMALE; HUMAN; INJURY; MATERNAL AGE; MIDDLE AGED; PATHOPHYSIOLOGY; PELVIC ORGAN PROLAPSE; PELVIS FLOOR; PREGNANCY; REVIEW; RISK FACTOR; STRESS INCONTINENCE; THREE DIMENSIONAL IMAGING; UTERUS PROLAPSE;

ADULT; DELIVERY, OBSTETRIC; FECAL INCONTINENCE; FEMALE; HUMANS; IMAGING, THREE-DIMENSIONAL; MATERNAL AGE; MIDDLE AGED; PELVIC FLOOR; PELVIC ORGAN PROLAPSE; PREGNANCY; RISK FACTORS; URINARY INCONTINENCE, STRESS; UTERINE PROLAPSE;

EID: 84859297658     PISSN: 09607692     EISSN: 14690705     Source Type: Journal    
DOI: 10.1002/uog.11080     Document Type: Review

References (116)

1. Kearney R, Sawhney R, DeLancey JO,. Levator ani muscle anatomy evaluated by origin-insertion pairs. Obstet Gynecol 2004; 104: 168-173. (Pubitemid 40458921)
2. 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.
3. Lien KC, Mooney B, DeLancey JO, Ashton-Miller JA,. Levator ani muscle stretch induced by simulated vaginal birth. Obstet Gynecol 2004; 103: 31-40. (Pubitemid 39248463)
4. Ashton-Miller JA, DeLancey JO,. Functional anatomy of the female pelvic floor. Ann N Y Acad Sci 2007; 1101: 266-296. (Pubitemid 47092720)
5. Thakar R, Sultan AH,. Anal endosonography and its role in assessing the incontinent patient. Best Pract Res Clin Obstet Gynaecol 2004; 18: 157-173. (Pubitemid 38324642)
6. Herschorn S,. Female pelvic floor anatomy: the pelvic floor, supporting structures, and pelvic organs. Rev Urol 2004; 6 (Suppl 5): S2-S10.
7. Hoyte L, Damaser MS,. Magnetic resonance-based female pelvic anatomy as relevant for maternal childbirth injury simulations. Ann N Y Acad Sci 2007; 1101: 361-376. (Pubitemid 47092707)
8. DeLancey JO, Starr RA,. Histology of the connection between the vagina and levator ani muscles. Implications for urinary tract function. J Reprod Med 1990; 35: 765-771. (Pubitemid 20252395)
9. Barber MD, Bremer RE, Thor KB, Dolber PC, Kuehl TJ, Coates KW,. Innervation of the female levator ani muscles. Am J Obstet Gynecol 2002; 187: 64-71. (Pubitemid 34800302)
10. Junginger B, Baessler K, Sapsford R, Hodges PW,. Effect of abdominal and pelvic floor tasks on muscle activity, abdominal pressure and bladder neck. Int Urogynecol J 2010; 21: 69-77.
11. Sapsford RR, Hodges PW,. Contraction of the pelvic floor muscles during abdominal maneuvers. Arch Phys Med Rehabil 2001; 82: 1081-1088. (Pubitemid 32744335)
12. Hoyte L, Damaser MS, Warfield SK, Chukkapalli G, Majumdar A, Choi DJ, Trivedi A, Krysl P,. Quantity and distribution of levator ani stretch during simulated vaginal childbirth. Am J Obstet Gynecol 2008; 199: 198.e1-5.
13. Valsky DV, Lipschuetz M, Bord A, Eldar I, Messing B, Hochner-Celnikier D, Lavy Y, Hohen 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.
14. Dietz HP, Lanzarone V,. Levator trauma after vaginal delivery. Obstet Gynecol 2005; 106: 707-712. (Pubitemid 41362172)
15. Shek KL, Dietz HP,. Can levator avulsion be predicted antenatally? Am J Obstet Gynecol 2010; 202: 586.e1-6.
16. Blasi I, Fuchs I, D'Amico R, Vinci V, La Sala GB, Mazza V, Henrich W,. Intrapartum translabial three-dimensional ultrasound visualization of levator trauma. Ultrasound Obstet Gynecol 2011; 37: 88-92.
17. Shek K, Dietz HP,. Intrapartum risk factors for levator trauma. BJOG 2010; 117: 1485-1492.
18. Svabik K, Shek KL, Dietz HP,. How much does the levator hiatus have to stretch during childbirth? BJOG 2009; 116: 1657-1662.
19. Brooks SV, Zerba E, Faulkner JA,. Injury to muscle fibres after single stretches of passive and maximally stimulated muscles in mice. J Physiol 1995; 488: 459-469.
20. Lin AS, Carrier S, Morgan DM, Lue TF,. Effect of simulated birth trauma on the urinary continence mechanism in the rat. Urology 1998; 52: 143-151. (Pubitemid 28317948)
21. Gilpin SA, Gosling JA, Smith AR, Warrell DW,. The pathogenesis of genitourinary prolapse and stress incontinence of urine. A histological and histochemical study. Br J Obstet Gynaecol 1989; 96: 15-23. (Pubitemid 19046105)
22. Gosling JA, Dixon JS, Critchley HO, Thompson SA,. A comparative study of the human external sphincter and periurethral levator ani muscles. Br J Urol 1981; 53: 35-41. (Pubitemid 11188481)
23. Keane DP, Sims TJ, Abrams P, Bailey AJ,. Analysis of collagen status in premenopausal nulliparous women with genuine stress incontinence. Br J Obstet Gynaecol 1997; 104: 994-998. (Pubitemid 27400177)
24. Dietz HP,. Pelvic floor ultrasound: a review. Am J Obstet Gynecol 2010; 202: 321-334.
25. Dietz H,. Pelvic floor assessment. Fetal Maternal Med Rev 2009; 20: 49-66.
26. Balmforth J, Toozs-Hobson P, Cardozo L,. Ask not what childbirth can do to your pelvic floor but what your pelvic floor can do in childbirth. Neurourol Urodyn 2003; 22: 540-542.
27. South MM, Stinnett SS, Sanders DB, Weidner AC,. Levator ani denervation and reinnervation 6 months after childbirth. Am J Obstet Gynecol 2009; 200: 519.e1-7.
28. Snooks SJ, Swash M, Henry MM, Setchell M,. Risk factors in childbirth causing damage to the pelvic floor innervation. Int J Colorectal Dis 1986; 1: 20-24. (Pubitemid 18002888)
29. Snooks SJ, Setchell M, Swash M, Henry MM,. Injury to innervation of pelvic floor sphincter musculature in childbirth. Lancet 1984; 2: 546-550. (Pubitemid 14072058)
30. Allen RE, Hosker GL, Smith AR, Warrell DW,. Pelvic floor damage and childbirth: a neurophysiological study. Br J Obstet Gynaecol 1990; 97: 770-779. (Pubitemid 20283313)
31. Snooks SJ, Henry MM, Swash M,. Faecal incontinence due to external anal sphincter division in childbirth is associated with damage to the innervation of the pelvic floor musculature: a double pathology. Br J Obstet Gynaecol 1985; 92: 824-828. (Pubitemid 16172052)
32. 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. (Pubitemid 44792640)
33. Kisli E, Kisli M, Agargun H, Altinokyigit F, Kamaci M, Ozman E, Kotan C,. Impaired function of the levator ani muscle in the grand multipara and great grand multipara. Tohoku J Exp Med 2006; 210: 365-372. (Pubitemid 44883977)
34. Shafik A, El-Sibai O,. Study of the levator ani muscle in the multipara: role of levator dysfunction in defecation disorders. J Obstet Gynaecol 2002; 22: 187-192. (Pubitemid 34407427)
35. Snooks SJ, Henry MM, Swash M,. Anorectal incontinence and rectal prolapse: differential assessment of the innervation to puborectalis and external anal sphincter muscles. Gut 1985; 26: 470-476. (Pubitemid 15064712)
36. Smith AR, Hosker GL, Warrell DW,. The role of partial denervation of the pelvic floor in the aetiology of genitourinary prolapse and stress incontinence of urine. A neurophysiological study. Br J Obstet Gynaecol 1989; 96: 24-28. (Pubitemid 19046106)
37. Snooks SJ, Swash M, Mathers SE, Henry MM,. Effect of vaginal delivery on the pelvic floor: a 5-year follow-up. Br J Surg 1990; 77: 1358-1360.
38. Weidner AC, Barber MD, Visco AG, Bump RC, Sanders DB,. Pelvic muscle electromyography of levator ani and external anal sphincter in nulliparous women and women with pelvic floor dysfunction. Am J Obstet Gynecol 2000; 183: 1390-1399; discussion 1399-1401.
39. DeLancey JO, Kearney R, Chou Q, Speights S, Binno S,. The appearance of levator ani muscle abnormalities in magnetic resonance images after vaginal delivery. Obstet Gynecol 2003; 101: 46-53. (Pubitemid 36057087)
40. Branham V, Thomas J, Jaffe T, Crockett M, South M, Jamison M, Weidner A,. Levator ani abnormality 6 weeks after delivery persists at 6 months. Am J Obstet Gynecol 2007; 197: 65.e1-6.
41. Tunn R, Delancey JO, Howard D, Ashton-Miller JA, Quint LE,. Anatomic variations in the levator ani muscle, endopelvic fascia, and urethra in nulliparas evaluated by magnetic resonance imaging. Am J Obstet Gynecol 2003; 188: 116-121. (Pubitemid 36135606)
42. Kearney R, Miller JM, Ashton-Miller JA, DeLancey JO,. Obstetric factors associated with levator ani muscle injury after vaginal birth. Obstet Gynecol 2006; 107: 144-149.
43. Yousuf AA, DeLancey JO, Brandon CJ, Miller JM,. Pelvic structure and function at 1 month compared to 7 months by dynamic magnetic resonance after vaginal birth. Am J Obstet Gynecol 2009; 201: 514.e1-7.
44. Dietz HP, Gillespie AV, Phadke P,. Avulsion of the pubovisceral muscle associated with large vaginal tear after normal vaginal delivery at term. Aust N Z J Obstet Gynaecol 2007; 47: 341-344. (Pubitemid 47079565)
45. Quinn M,. Injuries to the levator ani in unexplained, chronic pelvic pain. J Obstet Gynaecol 2007; 27: 828-831.
46. Shobeiri SA, Chimpiri AR, Allen A, Nihira MA, Quiroz LH,. Surgical reconstitution of a unilaterally avulsed symptomatic puborectalis muscle using autologous fascia lata. Obstet Gynecol 2009; 114: 480-482.
47. 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.
48. Lewicky-Gaupp C, Brincat C, Yousuf A, Patel DA, Delancey JO, Fenner DE,. Fecal incontinence in older women: are levator ani defects a factor? Am J Obstet Gynecol 2010; 202: 491.e1-6.
49. Adekanmi OA, Freeman RM, Jackson SA, Puckett M, Bombieri L, Waterfield MR,. Do the anatomical defects associated with cystocele affect the outcome of the anterior repair? A clinical and radiological study. Int Urogynecol J Pelvic Floor Dysfunct 2009; 20: 1369-1377.
50. Novellas S, Chassang M, Verger S, Bafghi A, Bongain A, Chevallier P,. MR features of the levator ani muscle in the immediate postpartum following cesarean delivery. Int Urogynecol J 2010; 21: 563-568.
51. Ismail SI, Shek KL, Dietz HP,. Unilateral coronal diameters of the levator hiatus: baseline data for the automated detection of avulsion of the levator ani muscle. Ultrasound Obstet Gynecol 2010; 36: 375-378.
52. Dietz HP, Shek KL,. Levator defects can be detected by 2D translabial ultrasound. Int Urogynecol J Pelvic Floor Dysfunct 2009; 20: 807-811.
53. Shek KL, Dietz HP,. The effect of childbirth on hiatal dimensions. Obstet Gynecol 2009; 113: 1272-1278.
54. Abdool Z, Shek KL, Dietz HP,. The effect of levator avulsion on hiatal dimension and function. Am J Obstet Gynecol 2009; 201: 89.e1-5.
55. Dietz HP, Kirby A,. Modelling the likelihood of levator avulsion in a urogynaecological population. Aust N Z J Obstet Gynaecol 2010; 50: 268-272.
56. Dietz HP, Kirby A, Shek KL, Bedwell PJ,. Does avulsion of the puborectalis muscle affect bladder function? Int Urogynecol J Pelvic Floor Dysfunct 2009; 20: 967-972.
57. Dietz HP, Shek C,. Levator avulsion and grading of pelvic floor muscle strength. Int Urogynecol J Pelvic Floor Dysfunct 2008; 19: 633-636. (Pubitemid 351516937)
58. Dietz HP, Simpson JM,. Levator trauma is associated with pelvic organ prolapse. BJOG 2008; 115: 979-984. (Pubitemid 351841765)
59. Dietz HP, Shek C, De Leon J, Steensma AB,. Ballooning of the levator hiatus. Ultrasound Obstet Gynecol 2008; 31: 676-680.
60. Dietz HP, Abbu A, Shek KL,. The levator-urethra gap measurement: a more objective means of determining levator avulsion? Ultrasound Obstet Gynecol 2008; 32: 941-945.
61. Dietz HP, Shek C,. Validity and reproducibility of the digital detection of levator trauma. Int Urogynecol J Pelvic Floor Dysfunct 2008; 19: 1097-1101.
62. Dietz HP, Shek KL,. The quantification of levator muscle resting tone by digital assessment. Int Urogynecol J Pelvic Floor Dysfunct 2008; 19: 1489-1493.
63. Dietz HP,. Repeatability of digital palpation for the detection of levator trauma. Int Urogynecol J Pelvic Floor Dysfunct 2007; 18: 156.
64. Dietz HP, Simpson JM,. Does delayed child-bearing increase the risk of levator injury in labour? Aust N Z J Obstet Gynaecol 2007; 47: 491-495. (Pubitemid 350075926)
65. Dietz HP,. Quantification of major morphological abnormalities of the levator ani. Ultrasound Obstet Gynecol 2007; 29: 329-334. (Pubitemid 46447319)
66. 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.
67. Dietz HP, Steensma AB,. The prevalence of major abnormalities of the levator ani in urogynaecological patients. BJOG 2006; 113: 225-230.
68. Eisenberg V, Chantarasorn V, Shek K, Dietz H,. Does levator ani injury affect cystocele type? Ultrasound Obstet Gynecol 2010; 36: 618-623.
69. Steensma AB, Konstantinovic MJ, Burger CW, de Ridder D, Timmerman D, Deprest J,. Prevalence of major levator abnormalities in symptomatic patients with an underactive pelvic floor contraction. Int Urogynecol J 2010; 21: 861-867.
70. Weemhoff M, Shek KL, Dietz HP,. Effects of age on levator function and morphometry of the levator hiatus in women with pelvic floor disorders. Int Urogynecol J 2010; 21: 1137-1142.
71. Weinstein MM, Pretorius D, Nager CW, Mittal RK,. Inter-rater reliability of pelvic floor muscles imaging abnormalities with 3D ultrasound. Ultrasound Obstet Gynecol 2007; 30: S 538.
72. Santoro GA, Wieczorek AP, Dietz HP, Mellgren A, Sultan A, Shobeiri SA, Stankiewicz A, Bartram C,. State of the art: an integrated approach to pelvic floor ultrasonography. Ultrasound Obstet Gynecol 2011; 37: 381-396.
73. Dietz HP, Steensma AB,. The role of childbirth in the aetiology of rectocele. BJOG 2006; 113: 264-267.
74. Krofta L, Otcenasek M, Kasikova E, Feyereisl J,. Pubococcygeus- puborectalis trauma after forceps delivery: evaluation of the levator ani muscle with 3D/4D ultrasound. Int Urogynecol J Pelvic Floor Dysfunct 2009; 20: 1175-1181.
75. DeLancey JO, Morgan DM, Fenner DE, Kearney R, Guire K, Miller JM, Hussain H, Umek W, Hsu Y, Ashton-Miller JA,. Comparison of levator ani muscle defects and function in women with and without pelvic organ prolapse. Obstet Gynecol 2007; 109: 295-302. (Pubitemid 46197419)
76. Dietz HP,. Levator function before and after childbirth. Aust N Z J Obstet Gynaecol 2004; 44: 19-23. (Pubitemid 38239693)
77. Hoyte L, Thomas J, Foster RT, Shott S, Jakab M, Weidner AC,. Racial differences in pelvic morphology among asymptomatic nulliparous women as seen on three-dimensional magnetic resonance images. Am J Obstet Gynecol 2005; 193: 2035-2040. (Pubitemid 41737630)
78. Handa VL, Lockhart ME, Fielding JR, Bradley CS, Brubakery L, Cundiffy GW, Ye W, Richter HE,. Racial differences in pelvic anatomy by magnetic resonance imaging. Obstet Gynecol 2008; 111: 914-920. (Pubitemid 351482624)
79. 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. (Pubitemid 34812267)
80. Laycock J, (ed). Clinical evaluation of the pelvic floor. Springer: London, 1994.
81. Bø K, Sherburn M,. Evaluation of female pelvic-floor muscle function and strength. Phys Ther 2005; 85: 269-282. (Pubitemid 40333546)
82. DeLancey JO, Trowbridge ER, Miller JM, Morgan DM, Guire K, Fenner DE, Weadock WJ, Ashton-Miller JA,. Stress urinary incontinence: relative importance of urethral support and urethral closure pressure. J Urol 2008; 179: 2286-2290.
83. Morgan DM, Cardoza P, Guire K, Fenner DE, DeLancey JO,. Levator ani defect status and lower urinary tract symptoms in women with pelvic organ prolapse. Int Urogynecol J 2010; 21: 47-52.
84. Weinstein MM, Pretorius DH, Jung SA, Nager CW, Mittal RK,. Transperineal three-dimensional ultrasound imaging for detection of anatomic defects in the anal sphincter complex muscles. Clin Gastroenterol Hepatol 2009; 7: 205-211.
85. Chantarasorn V, Shek KL, Dietz HP,. Sonographic detection of puborectalis muscle avulsion is not associated with anal incontinence. Aust N Z J Obstet Gynaecol 2011; 51: 130-135.
86. Morgan DM, Larson K, Lewicky-Gaupp C, Fenner DE, DeLancey JO,. Vaginal support as determined by levator ani defect status 6 weeks after primary surgery for pelvic organ prolapse. Int J Gynaecol Obstet 2011; 114: 141-144.
87. Weemhoff M, Vergeldt TF, Notten K, Serroyen J, Kampschoer PH, Roumen FJ,. Avulsion of puborectalis muscle and other risk factors for cystocele recurrence: a 2-year follow-up study. Int Urogynecol J 2012; 23: 65-71.
88. Dietz HP, Chantarasorn V, Shek KL,. Levator avulsion is a risk factor for cystocele recurrence. Ultrasound Obstet Gynecol 2010; 36: 76-80.
89. Model AN, Shek KL, Dietz HP,. Levator defects are associated with prolapse after pelvic floor surgery. Eur J Obstet Gynecol Reprod Biol 2010; 153: 220-223.
90. Dietz HP, Bernardo MJ, Kirby A, Shek KL,. Minimal criteria for the diagnosis of avulsion of the puborectalis muscle by tomographic ultrasound. Int Urogynecol J 2010; 22: 699-704.
91. Dietz HP, Shek KL,. Tomographic ultrasound imaging of the pelvic floor: which levels matter most? Ultrasound Obstet Gynecol 2009; 33: 698-703.
92. 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. (Pubitemid 43050208)
93. Kruger J, Dietz P, Botelho C, Dumoulin C,. Can we feel with our fingers as well as we see with ultrasound? Neurourol Urodyn 2010; 29: 1176-1177.
94. Fernandi M, Shek KL, Dietz HP,. Diagnosis of levator avulsion injury: a comparison of three methods. Neurourol Urodyn 2010; 29: 1019-1020.
95. Tunn R, Schaer G, Peschers U, Bader W, Gauruder A, Hanzal E, Koelbl H, Koelle D, Perucchini D, Petri E, Riss P, Schuessler B, Viereck V,. Updated recommendations on ultrasonography in urogynecology. Int Urogynecol J Pelvic Floor Dysfunct 2005; 16: 236-241. (Pubitemid 40867397)
96. Dietz HP,. Ultrasound imaging of the pelvic floor. Part I: two-dimensional aspects. Ultrasound Obstet Gynecol 2004; 23: 80-92. (Pubitemid 38122106)
97. Kruger JA, Heap SW, Murphy BA, Dietz HP,. Pelvic floor function in nulliparous women using three-dimensional ultrasound and magnetic resonance imaging. Obstet Gynecol 2008; 111: 631-638. (Pubitemid 351654067)
98. Dietz HP, Bhalla R, Chantarasorn V, Shek KL,. Avulsion of the puborectalis muscle is associated with asymmetry of the levator hiatus. Ultrasound Obstet Gynecol 2011; 37: 723-726.
99. Zhuang RR, Song YF, Chen ZQ, Ma M, Huang HJ, Chen JH, Li YM,. Levator avulsion using a tomographic ultrasound and magnetic resonance-based model. Am J Obstet Gynecol 2011; 205: 232.e1-8.
100. Kashihara H, Shek K, Dietz H,. Can we identify the limits of the puborectalis muscle on tomographic translabial ultrasound? Neurourol Urodyn 2010; 29: 1174-1176.
101. Erdmann M, Shek K, Dietz H,. Is there an association between levator function or morphometry and the ability to augment maximum urethral closure pressure voluntarily? Neurourol Urodyn 2010; 29: 824-825.
102. Shobeiri SA, Leclaire E, Nihira MA, Quiroz LH, O'Donoghue D,. Appearance of the levator ani muscle subdivisions in endovaginal three-dimensional ultrasonography. Obstet Gynecol 2009; 114: 66-72.
103. Santoro GA, Wieczorek AP, Stankiewicz A, Wozniak MM, Bogusiewicz M, Rechberger T,. High-resolution three-dimen- sional endovaginal ultrasonography in the assessment of pelvic floor anatomy: a preliminary study. Int Urogynecol J Pelvic Floor Dysfunct 2009; 20: 1213-1222.
104. Santoro GA, Wieczorek AP, Shobeiri SA, Mueller ER, Pilat J, Stankiewicz A, Battistella G,. Interobserver and interdisciplinary reproducibility of 3D endovaginal ultrasound assessment of pelvic floor anatomy. Int Urogynecol J 2011; 22: 53-59.
105. Margulies RU, Huebner M, DeLancey JO,. Origin and insertion points involved in levator ani muscle defects. Am J Obstet Gynecol 2007; 196: 251.e1-5.
106. Tunn R, DeLancey JO, Quint EE,. Visibility of pelvic organ support system structures in magnetic resonance images without an endovaginal coil. Am J Obstet Gynecol 2001; 184: 1156-1163. (Pubitemid 32434267)
107. Chou Q, DeLancey JO,. A structured system to evaluate urethral support anatomy in magnetic resonance images. Am J Obstet Gynecol 2001; 185: 44-50. (Pubitemid 32681792)
108. Tunn R, DeLancey JO, Howard D, Thorp JM, Ashton-Miller JA, Quint LE,. MR imaging of levator ani muscle recovery following vaginal delivery. Int Urogynecol J Pelvic Floor Dysfunct 1999; 10: 300-307. (Pubitemid 29465395)
109. Tunn R, Paris S, Fischer W, Hamm B, Kuchinke J,. Static magnetic resonance imaging of the pelvic floor muscle morphology in women with stress urinary incontinence and pelvic prolapse. Neurourol Urodyn 1998; 17: 579-589. (Pubitemid 28499041)
110. Tunn R, DeLancey JO, Howard D, Ashton-Miller J, Quint L, Goedicke J,. Evaluation of the levator ani muscle structure using different MR imaging techniques. Neurourol Urodyn 1999; 18: 310-311.
111. Miller JM, Brandon C, Jacobson JA, Low LK, Zielinski R, Ashton-Miller J, DeLancey JO,. MRI findings in patients considered high risk for pelvic floor injury studied serially after vaginal childbirth. AJR Am J Roentgenol 2010; 195: 786-791.
112. Majida M, Brækken IH, Bø K, Šaltyte Benth J, Engh ME,. Validation of 3D perineal ultrasound and MRI measurements of the pubovisceral muscle at rest. Ultrasound Obstet Gynecol 2010; 35: 715-722.
113. Dietz HP, Shek C, Clarke B,. Biometry of the pubovisceral muscle and levator hiatus by three-dimensional pelvic floor ultrasound. Ultrasound Obstet Gynecol 2005; 25: 580-585. (Pubitemid 40835462)
114. Jelovsek JE, Maher C, Barber MD,. Pelvic organ prolapse. Lancet 2007; 369: 1027-1038. (Pubitemid 46436126)
115. Ashton-Miller JA, Delancey JO,. On the biomechanics of vaginal birth and common sequelae. Annu Rev Biomed Eng 2009; 11: 163-176.
116. Shek KL, Langer S, Chantarasorn M, Dietz HP,. Does the Epi-No prevent levator trauma? A randomised controlled trial. Neurourol Urodyn 2010; 29: 1021-1022.