Urologic injuries during obstetric delivery are uncommon and nearly always preventable with careful planning, attention to detail, and meticulous technique.

As the most common surgical procedure in the world, cesarean delivery can often be misinterpreted as something simple during which care and attention are taken for granted. This notion should be replaced with the diligence and attention often reserved for other surgical procedures that are perceived to be more complex.

When urologic injury occurs at the time of delivery, it is critical to recognize the injury and to repair it whenever possible during the incident procedure. Delays in recognition, diagnosis, and treatment can lead to debilitating, prolonged suffering for the patient.

Urologic complications are the most common complications in obstetric surgery, and the bladder is the most likely organ to be injured. The incidence of bladder injury during cesarean section ranges from 0.08% to 0.94% (1). The risk of bladder injury at the time of cesarean increases with a history of prior cesarean delivery and numbers of cesarean deliveries, emergency delivery, and timing of the surgery (risk is higher in the second stage of labor vs. first). The highest risk is observed in women who undergo an unsuccessful trial of labor after cesarean delivery (1).

Ureteral injury at the time of cesarean delivery is rare but should be suspected in cases of prolonged obstructed labor and extensive adhesive disease with distorted anatomy (extensive prior surgery, endometriosis, cancer, or other conditions that distort the pelvic anatomy). Prolonged obstructed labor results in significant distortion of normal surgical planes and difficulty in identification of the bladder and ureter.

A high index of suspicion for this rare complication is essential to prevent patient morbidity and possible mortality. Various approaches can be employed to identify and repair ureteral injury.

Urologic injury as a result of instrumental vaginal delivery is also rare. Perineal and anal sphincter trauma are much more common and covered separately. In a series of >3.5 million deliveries in California with over 250,000 instrumental deliveries, there were no noted urologic injuries (2). The reporting of urologic injury with instrumental delivery remains at the case report level in the scientific literature; however, in low-income countries where access to proper instrumentation and training are limited, we have seen extensive bladder trauma and large vesicovaginal fistula related to vacuum-assisted delivery.

Preoperative imaging to prevent urologic injury in obstetric deliveries is uncommon outside of the use of ultrasound and magnetic resonance imaging (MRI) for placentation abnormalities (Chapter 4.9). Detection of significant adhesive disease after prior cesarean delivery has been described, but the implications for safer surgery in subsequent deliveries are unclear.

Extensive adhesive disease in the abdomen or pelvis noted by ultrasound or MRI may assist in planning for the next cesarean, but the utility of these diagnostic modalities for this purpose remains unproven (3). Similarly, the type and extent of the abdominal incision from prior surgeries cannot accurately predict the complexity of the adhesions encountered during the incident surgery (4).

Intraoperatively, a number of modalities aid in the detection of urologic injury. Many obstetric operating tables and rooms have the capacity for intraoperative radiologic imaging, but the utility of fluoroscopic examination of the ureter or bladder after cesarean delivery in the majority of the case is limited.

A more practical approach involves careful surgical inspection for injury, restoration of normal anatomy, identification of the relevant pelvic anatomy, and the use of different dyes to establish the integrity of the urinary tract (see Section Procedures and Techniques in this chapter).

An interesting evolution of the use of infant formula to establish bladder integrity arose owing to the proximity of nurseries to obstetric operating rooms. Although convenient and easy to administer, there is a hypothetical increased risk of infection using this makeshift dye.

Other dyes include indigo carmine, methylene blue, indocyanine green, and phenazopyridine. Indigo carmine is the best all-purpose dye in terms of convenience, safety, and the ability to visualize any part of the urinary tract after intravenous (IV) or direct instillation. Indigo carmine shortages have occurred in the last decade owing to the availability of raw materials, so alternative options can be considered such as sodium fluorescein and others (5).

Dilute methylene blue can be used for direct bladder installation and has been proven safe. IV methylene blue is generally safe but can be complicated by cardiovascular side effects, serotonin syndrome, methemoglobinemia, and a universal and often disconcerting, but benign, phenomenon of transient, decreased measured oxygen saturation on monitoring.

Indocyanine green use is limited by potential side effects and availability. Oral phenazopyridine can be used preoperatively, but given the rarity of ureteral injury in cesarean, this would have very limited utility in obstetric deliveries.

There are a number of factors to be considered when planning a cesarean delivery to avoid urologic injury. Prior cesarean delivery and the number of prior cesarean deliveries create the highest risks for bladder injury.

Adhesive disease caused by endometriosis, prior pelvic surgery (especially myomectomy), pelvic inflammatory disease, and other conditions predisposes to distorted anatomy and may contribute to urologic injury during cesarean delivery, including ureteral injury.

Congenital anomalies including duplicated ureter or pelvic horseshoe kidney generally remain unrecognized during a typical cesarean delivery and may only be a concern if there are other complications or distortions in anatomy.

Often, cesarean delivery is performed on an emergent basis, and the benefit of time to secure prior operative notes or extensive surgical history can be limited, so the surgeon must be prepared to deal with anything encountered. When possible, having prior operative notes available for review can be helpful in planning.