Manometric and ultrasonographic assessment of anal sphincter function following forceps or vacuum assisted vaginal delivery

ABSTRACT

To compare differences in anal sphincter function following vacuum or forceps assisted vaginal delivery. Prospective, r and omized controlled trial. Al-Azhar University Hospitals in Damietta and Cairo.One hundred and thirty primiparous women were recruited antenatally and if an instrumental delivery was indicated, were r and omized to either a vacuum or low-cavity, non-rotational forceps assisted delivery. Follow-up consisted of a symptom questionnaire, anal manometry, and endoanal ultrasonography. Faecal continence scores, anal manometry and endoanal ultrasonography. Sixty-one women delivered with forceps assistance [42 for failure to progress in the second stage] and 69 with vacuum assistance [50 for failure to progress]; 16/69 vacuum deliveries proceeded to a forceps assisted delivery [23%]. There were no statistical differences in the antecedent antenatal factors between the two groups. A third degree perineal tear followed 7 [11%] forceps and 3 [4%] vacuum deliveries. Based on intention-to-treat analysis, 32 [52%] women complained of altered faecal continence after forceps delivery compared with 21 [30%] following vacuum delivery three months postpartum. Endoanal ultrasonography was reported as abnormal following 34 [56%] forceps deliveries and 34 [49%] vacuum deliveries. After exclusion of 'failed vacuum', median anal canal resting pressure was significantly lower following forceps delivery compared with vacuum delivery alone [p<0.001]. There were no significant differences in degree of ultrasound abnormality between the two groups. Symptoms of altered faecal continence are significantly more common following forceps assisted vaginal delivery. Based on continence outcome, when circumstances allow, vacuum should be the instrument of first choice in assisted delivery