Page 93 - หนังสือประชุมวิชาการ

Preventive measures for OASIS

For primary prevention of OASIS, clinicians need to be aware of the identifiable risk factors.
These include Asian ethnicity, nulliparity, birthweight greater than 4 kg, shoulder dystocia,

occipito-posterior position, prolonged second stage of labor, and instrumental delivery. All

women at risk especially those with multiple predisposing factors should receive special attention

during intrapartum and immediate postpartum period. Obstetricians and related healthcare
personnel should foresee the possibility of sphincter trauma in individuals at risk. Protective

interventions such as warm compression during the second stage of labor, mediolateral

episiotomy, and perineal protection at crowning can be implemented. Informative counseling

should be given whenever operative vaginal delivery is indicated. Moreover, early decision
making for cesarean delivery may be considered in case of persistent occiput posterior position

and a tendency of prolonged labor. For secondary prevention, thorough and systematic

examination of perineal wound after vaginal delivery, especially digital rectal examination or pill

rolling action (thumb & index), is mandatory for early OASIS detection. Finally, a standardized
repair technique conducted by an appropriately trained clinician or a trainee under supervision is

essential for effective primary repair of obstetric anal sphincter injuries. To achieve all 3

preventive measures, many domestic and international hands-on workshops have been

organized worldwide to help increase awareness of OASIS risk factors and early recognition of
anal sphincter injuries, as well as to improve surgical skills of OASIS repair among obstetricians

and related healthcare personnel.

OASIS was defined according to the Royal College of Obstetricians and Gynaecologists

(RCOG) classification of perineal trauma as the third- and fourth-degree tears of which injuries
(2)
involved the anal sphincter complex. The following classification described by Sultan et al has
been adopted by the International Consultation on Incontinence and the RCOG.

Obstetric Anal Sphincter Injuries (OASIS): Impact and Management 76