Pelvic fractures in motor vehicle accidents mean that great forces were at work in the accident and usually mean that the patient is injured in places outside the pelvic area. Pelvic fractures can be stable or unstable, depending on the location of the fracture and the number of fractures in the pelvic ring. Mortality can be up to thirty percent in unstable fractures with about 10 percent due to excessive bleeding alone.
A total of 57 percent of pelvic fractures are due to being a passenger in a motor vehicle accident. Eighteen percent are from being a pedestrian hit by a car, while 9 percent are from motorcycle crashes. Falls and crush injuries make up the rest of the injuries.
There is an unstable fracture of the pelvis called an “open book” pelvic fracture. It involves fractures In multiple areas of the pelvic ring. Patients can die from exsanguination (severe blood loss) and can have complications related to the genitourinary tract, bowel damage, damage to nerves, laceration of the vagina, sepsis and chronic pain.
The pelvis is actually a ring of bones, consisting of the sacrum and two bones made from the fusion of two ilia, two pubic bones and two ischiums. Together the three bones are called the innominate bone. The sacroiliac joint is very strong–believed to be the strongest joint in the body. It normally doesn’t move but can become disarticulated when severe forces are applied to it. There are major blood vessels travelling along the inner wall of the pelvic ring and a fracture can disrupt these vessels, leading to severe bleeding. Both arteries and veins can be affected.
Other organs affected in pelvic fractures include the bladder and the urethra, which can be damaged in both men and women, the prostate gland in men, the vagina in women and the GI tract. Puncturing the GI tract can lead to peritonitis and death from sepsis. In some cases, the nerve plexuses that travel near the pelvis can be damaged, leading to bowel, bladder and lower extremity dysfunction.
One study looked at 130 female patients who sustained high speed motor vehicle or pedestrian motor vehicle collisions and who had a pelvic fracture. A total of 6 of these women sustained a urethral injury and many of them suffered from partial disruption of the urethra that, when the Foley catheter was removed, urine extravasated into the pelvic space. Several patients had moderate to severe vulvar edema secondary to bleeding and swelling about the pelvis. Two patients had rupture of the bowel with sepsis that was life threatening and a condition known as necrotizing fasciitis. Doctors noted that 80 percent of patients suffered bleeding at the vaginal introitus, consistent with vaginal injuries. Half of all these patients, however, were able to have a thorough vaginal exam to see if there needed to be repair of the vaginal wall.
Of those who had thorough exams, two thirds were found to have damage to either the bladder or the vaginal wall. Cystoscopic exams in some patients showed rupture or laceration of the bladder or disruption of the urethra.