Structural support of the urethra as it relates to stress urinary incontinence: The hammock hypothesis


      OBJECTIVE: This study examines the anatomic factors that could explain the mechanical basis for transmission of abdominal pressure to the urethra. STUDY DESIGN: Dissection of 19 embalmed and 42 fresh cadavers and examination of 13 sets of serial pelvic sections were performed to study the structures involved in urethral support. The effect of simulated increases in abdominal pressure on the pelvic floor and urethra was observed in fresh specimens. RESULTS: The urethra lies on a supportive layer that is composed of the endopelvic fascia and the anterior vaginal wall. This layer gains structural stability through its lateral attachment to the arcus tendineus fascia pelvis and levator ani muscle. Pressure from above compresses the urethra against this hammock-like supportive layer, compressing its lumen closed. The stability of the suburethral layer depends on the intact connection of the vaginal wall and endopelvic fascia to the arcus tendineus fasciae pelvis and levator ani muscles. CONCLUSION: Increases in urethral closure pressure during a cough probably arise because the urethra is compressed against a hammock-like supportive layer, rather than the urethra being truly “intraabdominal.” (AM J Obstet Gynecol 1994;170:1713-23.)


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        • Enhorning G
        Simultaneous recording of the intravesical and intraurethral pressure.
        Acta Obstet Gynecol Scand. 1961; 276: 1-69
        • Fantl JA
        • Hurt WG
        • Bump RC
        • Dunn LJ
        • Choi SC
        Urethral axis and sphincteric function.
        AM J OBSTET GYNECOL. 1986; 155: 554-558
        • Galloway NTM
        • Davies N
        • Stephenson TP
        The complications of colposuspension.
        Br J Urol. 1987; 60: 122-124
        • Lose G
        • Jorgensen L
        • Mortensen SO
        • Molsted-Pedersen L
        • Kristensen JK
        Voiding difficulties after colposuspension.
        Obstet Gynecol. 1987; 69: 33-38
        • Burch J
        Cooper's ligament urethrovesical suspension for stress incontinence.
        AM J OBSTET GYNECOL. 1968; 100: 764-772
        • Wiskind AK
        • Creighton SM
        • Stanton SL
        The incidence of genital prolapse following the burch colposuspension operation.
        Neurourol Urodynam. 1991; 10: 453-454
        • Cardozo LD
        • Stanton SL
        • Williams JE
        Detrusor instability following surgery for genuine stress incontinence.
        Br J Urol. 1979; 51: 204-207
        • DeLancey JOL
        Structural aspects of the extrinsic continence mechanism.
        Obstet Gynecol. 1988; 72: 296-301
        • DeLancey JOL
        Correlative study of paraurethral anatomy.
        Obstet Gynecol. 1986; 68: 91-97
        • Richter K
        Lebendige anatomie der vagina.
        Geburtshilfe Frauenheilkd. 1966; 26: 1213-1223
        • Dickinson RL
        An atlas of sex anatomy.
        Williams and Wilkins, Baltimore1950
        • Funt MI
        • Thompson JD
        • Birch H
        Normal vaginal axis.
        South Med J. 1978; 71: 1534-1535
        • Oelrich TM
        The striated urogenital sphincter muscle in the female.
        Anat Rec. 1983; 205: 223-232
        • Jeffcoate TNA
        • Roberts H
        Observations on stress incontinence of urine.
        AM J OBSTET GYNECOL. 1952; 64: 721-738
        • Hodgkinson CP
        Relationships of the female urethra and bladder in urinary stress incontinence.
        AM J OBSTET GYNECOL. 1953; 65: 560-575
        • Lapides J
        • Ajemian EP
        • Steward BH
        • Lichtwardt JR
        • Breakey BA
        Physiopathology of stress incontinence.
        Surg Gynecol Obstet. 1960; 111: 224-231
        • Richardson AC
        • Edmonds PB
        • Williams NL
        Treatment of stress urinary incontinence due to paravaginal fascial defect.
        Obstet Gynecol. 1981; 57: 357-362
        • Shull BL
        • Baden WF
        A six-year experience with paravaginal defect repair for stress urinary incontinence.
        AM J OBSTET GYNECOL. 1989; 160: 1432-1439
        • Zaccharin RF
        The anatomic supports of the female urethra.
        Obstet Gynecol. 1968; 21: 754-759
        • Noll LE
        • Hutch JA
        The SCIPP line—an aid in interpreting the voiding lateral cystourethrogram.
        Obstet Gynecol. 1969; 33: 680-689
        • Muellner SR
        Physiology of micturition.
        J Urol. 1951; 65: 805-810
        • Bump RC
        • Huang KC
        • McClish DK
        • Fantl JA
        Effect of narcotic anesthesia and skeletal muscle paralysis on passive and dynamic urethral function of stress continent and incontinent women.
        Neurourol Urodynam. 1991; 10: 523-532
        • Snooks SJ
        • Badenoch DF
        • Tiptaft RC
        • Swash M
        Perineal nerve damage in genuine stress urinary incontinence. An electrophysiological study.
        Br J Urol. 1985; 57: 422-426
        • Wells TJ
        • Brink CA
        • Diokno AC
        • Wolfe R
        • Gillis GL
        Pelvic muscle exercise for stress urinary incontinence in elderly women.
        J Am Geriatr Soc. 1991; 39: 785-791
        • McGuire EJ
        Urodynamic findings in patients after failure of stress incontinence operations.
        Prog Clin Biol Res. 1981; 78: 351-360
        • Constantinou CE
        • Govan DE
        Spatial distribution and timing of transmitted and reflexly generated urethral pressures in healthy women.
        J Urol. 1982; 127: 964-969
        • White GR
        Radical cure for cystocele.
        JAMA. 1909; 21: 1707
        • Constantinou CE
        • Govan DE
        Spacial distribution and timing of transmitted and reflexly generated urethral pressures in healthy women.
        J Urol. 1982; 127: 964-969
        • Thind P
        • et al.
        Urethral pressure increment preceding and following bladder pressure elevation during stress episode in healthy and stress incontinent women.
        Neurourol Urodynam. 1991; 10: 177-183
        • Benson T
        Proceedings of the nineteenth annual meeting of the Society of Gynecologic Surgeons, Phoenix, Arizona, March 1-3, 1993.
        Phoenix: Society of Gynecologic Surgeons. 1993
        • DeLancey JOL
        Structural aspects of the extrinsic continence mechanism.
        Obstet Gynecol. 1988; 72: 296-301
        • Shafik A
        Micturition and urinary continence: new concepts.
        Int Urogynecol J. 1992; 3: 168-175
        • Lose G
        Urethral pressure and power generation during coughing and voluntary contraction of the pelvic floor in females with genuine stress incontinence.
        Br J Urol. 1991; 67: 580-585
        • Versi E
        • Cardozo LD
        • et al.
        BMJ. 1986; 202: 166
        • Versi E
        • Cardozo LD
        • Studd JWW
        • Brincat M
        • O'Dowd DJ
        Internal urinary sphincter in maintenance of urinary continence.
        BMJ. 1986; 292: 166-167
        • Muellner SR
        Physiology of micturition.
        J Urol. 1951; 60: 805-810