Obstetric anal sphincter injuries (OASIs) are the most common cause of fecal incontinence in women. Studies have found a strong association between OASIs and decreased physical, emotional well-being of affected women. Sultan's classification divides perineal tears into four grades, two of which include OASIS and depend on the degree of sphincter damage. Third-degree perineal tears involve injury to the anal sphincter and are subdivided into: (3a) having less than 50% of EAS thickness torn, (3b) having more than 50% of EAS thickness torn, and (3c) having both EAS and IAS torn. Fourth-degree tears involve the anal sphincter as well as the anorectal epithelium or rectal mucosa [1]. Most sphincter tears can be identified clinically at the time of vaginal delivery in 0.6% to 9% of patients by a trained clinician. In those with recognized tears at the time of delivery, repair should be performed using long-term absorbable sutures [2]. The risk of presenting incontinence increases with time and is affected by a following pregnancy and mode of birth [3].
This audit aims to measure the prevalence of OASIs in a tertiary hospital in Northern Greece with high cesarean section rates.

Data was obtained from the patients' medical records and the hospital's database on OASIs management performed between January 2007 and April 2021. A retrospective medical record review was conducted identifying the patients and two authors collected the demographic data, the recording observations on the partogram, and the patient's medical record. The variables collected, analyzed, and measured were maternal age, parity, gestational week, induction of labor, use of obstetric analgesia, duration of the second stage of labor, use of mediolateral episiotomy, use of analgesia, mode of delivery, shoulder dystocia, birth weight, gender, instrument-assisted vaginal delivery, obstetrician's experience, OASIS' grade, type of suture, type of technique, type of anesthesia, hospital stay, antibiotics intake, laxative intake, follow-up. As part of the hospital's labor ward protocol, all OASIS were repaired in the operating theater.

From 2007 to 2020 21312 deliveries took place in our center. The vaginal delivery rate was 43.24% (9216/21312). Fifty-one women with OASIS were found (0.55%, 51/9216). 40 (40/51, 78.43%) had a minor tear (Grade 3a-3b), and 11 (11/51, 21.57%) had a major tear (Grade 3c-4). 34 (66.67%) women were nulliparous. The mean maternal age and the mean gestational week at delivery were 29±4.5 years and 39±1.0 week respectively. The mean duration of the 2nd stage of labor was 63.8±46.1 minutes. Instrumental assisted vaginal labor had the 22 out of 51 mainly due to prolongation of the 2nd stage of labor. 35 were boys and 16 were girls with mean birth weight 3592.9±389.3 gr. A mediolateral episiotomy was performed in 34 out of 51 (66.7%) women, whereas 17 (33.3%) women had a spontaneous trauma.  All 51 patients underwent primary sphincter repair. The end-to-end technique was used for the repair of grade 3a tears, while end-to-end or overlap repair was used for the repair of the rest of the tears, depending on the surgeon's experience. The mean hospitalization was 3.4±0.5 days.

A high cesarean section rate has a direct implication in the OASIs prevalence. Nevertheless, OASIs occur even in cesarean-friendly labor wards and the knowledge of recognition and appropriate repair appear to be of paramount importance. Reduction of cesarean birth rates has become a priority for several health societies around the world as it has been in our center. The lower the cesarean section rate, the higher the OASIs prevelance, thus the labour ward personnel should be appropriately trained to manage and repair correctly this type of injury.

OASIS are complications that occur during vaginal delivery and is a known risk factor for subsequent fecal incontinence in women. Sustaining a third- or fourth-degree tear can significantly impact a woman's physical and emotional health. This includes the development of anxiety and depression that makes women unable to discuss their symptoms and avoid seeking a medical opinion. Although OASIS and its impact on quality of life are recognized, the prevalence effect of perineal trauma in Greece may be relatively under-researched. By implementing a standard protocol in our labor ward, it has probably contributed to decrease the cesarean section in our unit. Our results indicate lower prevalence of OASIs to existing literature and demonstrate that when easier a decision for CS is made, lower are the perineal lacerations.

Sultan AH, Thakar R. Third and fourth degree tears. In Perineal and Anal Sphincter Trauma, Sultan AH, Thakar R, Fenner DE (eds). Springer-Verlag: London, 2007; 33–51.
Dudding TC, Vaizey CJ, Kamm MA. Obstetric anal sphincter injury: incidence, risk factors, and management. Ann Surg. 2008 Feb;247(2):224-37.
Pollack J, Nordenstam J, Brismar S, et al. Anal incontinence after vaginal delivery: a five-year prospective cohort study. Obstet Gynecol. 2004;104:1397–1402.