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Fecal Incontinence Diagnosis and Treatment - part 3

chứng minh rằng phụ nữ có xác nhận siêu âm khuyết tật cơ vòng, khoảng 90% liên quan đến cơ vòng hậu môn bên ngoài [101, 124-128], hoặc trong sự cô lập hoặc kết hợp với vỡ của các cơ vòng hậu môn nội bộ. Isolated khuyết tật nội bộ cơ vòng hậu môn ít hơn nhiều | 54 S.M. Scott P.J. Lunniss Table 6. Type of anal sphincter disruption identified on endoanal ultrasound Author Date Number of defects Isolated IAS defects Isolated EAS defects Combined IAS EAS defects All EAS defects Sultan et al. 97 1993 28 46 18 36 56 Abramowitz et al. 101 2000 39 10 85 590 Faltin et al. 124 2000 42 5 71 24 95 Chaliha et al. 105 2001 59 17 59 24 83 Belmonte-Montes et al. 125 2001 28 0 66 34 100 Nazir et al. 126 2002 14 7 79 14 93 Pinta et al. 127 2004 17 12 65 23 88 Damon et al. 128 2005 66 0 74 26 100 Summary data median range 33.5 8.5 68.5 24 91.5 14-66 0-46 18-85 5-36 56-100 IAS internal anal sphincter EAS external anal sphincter demonstrates that in women with ultrasonographic confirmation of sphincter defects approximately 90 involve the external anal sphincter 101 124-128 either in isolation or combined with rupture of the internal anal sphincter. Isolated internal anal sphincter defects are much less common accounting for 10 or less of all defects in the majority of studies 101 124-128 . In the absence of an overt tear i.e. an intact perineum it is presumed that such isolated defects in the internal anal sphincter result from shearing forces imposed during delivery 97 . Aside from sphincter damage the branches of the pudendal nerve which contains both motor and sensory fibres are vulnerable to stretch or compression injury which may occur during childbirth 157-163 when pelvic floor descent and progression of the foetal head towards the pelvic outlet may stretch the nerve as it emerges from Alcock s canal where its course is relatively fixed along the pelvic sidewall 95 . Multiparity instrumental delivery notably forceps protracted second stage of labour anal sphincter tears and high birthweight are identified risk factors 97 123 148 157 160 . In respect to parity first vaginal delivery appears from the results of prospective studies to be the most injurious to sphincter 5 120 123 135 and neural 123 160 integrity alike with damage to the .