Although we are becoming increasingly reliant on CT scans for diagnosis, plain old radiographs still have their place. This is especially true in pelvic imaging after trauma.
The most common pelvic radiograph obtained is the supine A-P view taken during trauma resuscitation. This image gives a quick and dirty look at the entire pelvis, from iliac crest to ischial tuberosity. The main areas of interest are the pubic symphysis and the SI joints, so if some of the periphery is cut off a repeat is not necessary prior to CT scan. This image helps predict the need for blood and pelvic compression devices.
If fractures are present, the orthopedic surgeons will generally request additional views in addition to the CT scan. The scan gives excellent detail, but the axial image slices are still not as good as a plain old radiograph in many cases.
Inlet and outlet views are used to get a better look at the pelvic ring. The inlet view opens the ring up into a big circle (or oval) and allows identification of fractures of the sacrum or displacement of the SI joints, as well as changes in the pubic symphysis. The outlet view shows any vertical displacements through the sacrum or SI joints well, and gives a better appreciation of some pubic fractures.
Judet views help demonstrate acetabular fractures by lining up the iliac wing with the xray tube. They can give additional information that the orthopedists use for determining operative or nonoperative management.
Rule of thumb: For major trauma patients, obtain an A-P pelvis radiograph if indicated by mechanism of injury or physical exam. Perform CT scan of the abdomen and pelvis if indicated. If a pelvic ring fracture is identified, obtain inlet and outlet radiographs before calling your orthopedic surgeon. If an acetabular fracture is seen, obtain Judet views before calling.
Fractures of the posterior pelvis are notorious for their potential to bleed. Here are some tips to use if you encounter a trauma patient with an unstable pelvis and want to slow down the bleeding in the ED.
First, figure out what type of pelvic fracture it is. You will probably be able to do this using physical exam and a simple A-P radiograph. Push down hard on the anterior superior iliac spines to see if the pelvis moves. If so, the patient has an anterior-posterior compression type fracture, and you will likely see diastasis of the pubic bones on the xray. These are amenable to compression maneuvers discussed here.
If the pelvis collapses with lateral compression of the iliac wings, then the patient has a lateral compression fracture and compression maneuvers should not be used. Similarly, if a vertical shear is seen on the xray, do not use compression maneuvers.
There are several pieces of equipment available to help compress the pelvis:
Commercial pelvic compression product (e.g. T-Pod). These are convenient but pricey.
MAST trousers – just inflate the abdominal compartment, not the legs. But who has these laying around any more?
Sheet – cheap and quick. Very effective if used properly.
To apply a sheet, it needs to be folded into a narrow band no more than 12 inches high. It should be passed under the patient’s legs and moved upwards. It must be centered over the greater trochanters. This will apply proper pressure, but will not cover the lower abdomen (think laparotomy) or the genitalia (think urinary catheter). Cross the ends of the sheet over as shown above, with one person holding the cinch point while the sheet is secured. This can be carried out with a knot or plastic clamps. Metal clamps will degrade CT or angiographic imaging and should not be used. The sheet should be left in place for the shortest period of time possible, as skin breakdown can occur.
The picture above on the left shows a sheet that is folded too wide (difficult to get enough tension, and covers the good stuff) and uses metal towel clips. The picture on the right shows the proper technique.
Sure, you’ve heard about all the other compartment syndromes: leg, thigh, forearm, buttock, and abdomen to name a few. But how about a compartment syndrome of the orbit?
This isn’t your usual muscular compartment problem, although the basic concept is the same. The eye is surrounded by rigid bones or relatively stiff soft tissue (the eyelid, believe it or not). Any extra tissue or blood added to this compartment dramatically raises the pressure in the area, which is readily conducted to the eye itself. This rapidly results in:
Severe eye pain
Decreased extraocular movements, which may result in diplopia
Decreased visual acuity
Increased intra-ocular pressure (>40 torr)
Slow pupillary response
This syndrome should be confirmed rapidly and is one of the few true ophthalmologic emergencies. A lateral canthotomy and cantholysis should be carried out to make the lower lid freely mobile, decompressing the compartment (see diagram). This procedure is not for the faint of heart, but should be familiar in any ED where an ophthalmologist is not readily available. Urgent followup with an eye specialist is mandatory.
Several of the performance improvement (PI) audit filters typically used at trauma centers include a time parameter. These include:
Craniotomy > 4 hrs
Laparotomy > 4 hrs
OR for open fracture > 8 hrs
Compartment syndrome > 2 hrs
The question that needs to be asked is: 2 or 4 or 8 hours after what?
There are several possible points at which to start the clock:
Arrival in the ED
When the diagnosis is made
When the decision to operate occurs
The answer is certainly open to interpretation. Here is my opinion on it:
The purpose of a PI filter is to measure system performance. There are a myriad of system problems that can delay taking a patient to the OR. These include care delays in the ED, delays in getting or interpreting diagnostic tests, delays in contact or response for consultants, delays in diagnosis, delays in OR scheduling or availability, and more. Does it make sense to limit the evaluation of your system by setting one of the later decision points as your start time?
Bottom line: I recommend starting the audit filter clock at the time of patient arrival in the ED. This enables the PI program to evaluate every system that can possibly enable or impede your patient’s progress to the OR.
I’ve previously written about management of extraperitoneal bladder injuries. One of the tenets is that every injury needs to have a routine followup cystogram to ensure healing and allow removal of any bladder catheter. I routinely like to question dogma, so I asked myself, is this really necessary? A retrospective registry review from the Ryder trauma center in Miami helped to answer this question.
Over 20,000 records were screened for bladder injury and 87 were found in living patients. Fifty were intraperitoneal injuries, and half of them were caused by pelvic fractures (interesting). All were operated on, and 47 were classified as simple (dome disruption or through and through penetrating) and 3 were “complex” (involving trigone). All trackable patients (42 of the 50) had followup cystograms 9-16 days later. All of the simple injuries had a normal followup exam, but a leak was detected on one of the complex injuries.
There were 42 patients with extraperitoneal bladder injuries. All were due to blunt trauma, and 92% were associated with pelvic fractures. Most were found with CT cystogram. Two patients had operative repair, probably due to the need to fix the pubic bones with hardware. 37 of the 42 were available for followup, and 22% of repeat cystograms were positive (average study done on day 9). In the studies that showed a leak, repeat cystograms were done, and they took an average of 47 days to fully heal.
Bottom line: Patients with extraperitoneal or complex intraperitoneal bladder injuries (trigone) really do need a followup cystogram before removing the bladder catheter. Those who underwent a simple repair of their intraperitoneal injury do not.