[Study of morphological changes in levator ani muscle of patients with stress urinary incontinence or pelvic organ prolapse].
OBJECTIVE
To investigate the morphological characteristics of levator ani muscle in patients with stress urinary incontinence (SUI) or pelvic organ prolapse (POP) and to explore whether the alterations could contribute to pathogenesis of the diseases.


METHODS
Biopsy specimens of levator ani muscle were obtained from 15 patients with SUI, 19 patients with POP and 3 asymptomatic controls with rectal cancer during operation. The structure of levator ani muscle was examined with routine histological techniques: HE staining, modified Gomori trichrome staining, NSE staining, ACP staining, and adenosine triphosphatase (ATPase) staining.


RESULTS
There was no significant difference in age, parity, menopausal time, disease severity and leak point pressure between SUI patients with or without muscle fibers (P > 0.05). The muscular fiber density of levator ani muscles in SUI and POP groups was decreased, fibers were arranged in disorder and separated by large quantities of dense connective tissues with infiltrating inflammatory cells. The muscle fiber fascicles showed obvious grouped denervative atrophy, fiber type grouping and angular in shape. And also there was myopathic degeneration such as centrally located nuclei, peripheral phagocytosis and vacuolated necrosis.


CONCLUSIONS
There are both neurogenic and myopathic alterations in levator ani muscle's structure in patients with SUI and POP. The presence of both acute and chronic abnormalities indicates that the weakness of pelvic floor is a consequence of prolonged denervation.
Chen
Juan
J
Department of Obstetrics and Gynecology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing 100730, China.
Lang
Jing-he
JH
Zhu
Lan
L
Liu
Zhu-feng
ZF
Sun
Da-wei
DW
Leng
Jin-hua
JH
Ren
Hai-tao
HT
Zhao
Yan-huan
YH
Guan
Hong-zhi
HZ
D000368:Aged; D001003:Anal Canal / Q000503:physiopathology; D005260:Female; D006801:Humans; D008875:Middle Aged; D018485:Muscle Fibers, Skeletal / Q000473:pathology; D018482:Muscle, Skeletal / Q000294:innervation*; D017773:Pelvic Floor / Q000294:innervation / Q000473:pathology*; D012005:Rectal Prolapse / Q000473:pathology* / Q000503:physiopathology; D014550:Urinary Incontinence, Stress / Q000473:pathology* / Q000503:physiopathology