1 Introduction topenlarge
Before proceeding with definitive repairs, the patient must be fully resuscitated, fully evaluated, and fit for anesthesia and surgery by a prepared team.
B3 pelvic ring injuries are bilateral posterior arch injuries which can be either B1 (externally rotated) or B2 (internally rotated).
If displacement occurs bilaterally, deformity of the entire pelvic ring can be significant. The three possible deformities are:
- Both sides externally rotated (B3.1)
- One side internally the other externally rotated (B3.2)
- Both sides internally rotated (B3.3)
Pelvic ring deformity is particularly evident in the wind swept appearance of the 3.2 (LC-III) injury.
With mobility and displacement of both hemipelves, reapproximation of each injury does not by itself guarantee correct alignment. Malreduction with excessive or insufficient rotation of the posterior injuries is possible, resulting in pelvic ring asymmetry. This can be recognized by displacement of the pubic symphysis away from the midline.
The goals of treatment are to restore:
- anatomical alignment of the pelvis, including normal shape and symmetry
- sufficient stability for patient mobility
Emergency care for pelvic ring injuries should be available and preplanned at every trauma hospital. Patients with complex pelvic ring injuries may need to be referred to a specialized center.
Lumbo-sacral nerve root injury
Before undertaking definitive treatment of pelvic ring injuries, It is essential to know the functional status of the patient's lumbosacral nerve roots. A careful and detailed examination is necessary, to assess perineal sensation, voluntary anal sphincter contraction, and bulbo-cavernosus reflex. Cystometrography may be helpful to assess bladder neuromotor function.
Neurologic abnormalities should be correlated with anatomic site of injury:
- If a lumbo-sacral nerve deficit is present in extra sacral injuries, further investigation and possible treatment must be considered.
- If a sacral nerve deficit is present with a sacral fracture, the nerves should be decompressed with fracture reduction and/or sacral laminectomy.
Pelvic ring stability
The B3 classification requires that both posterior injuries exhibit only rotational (partial) instability. This implies that a posterior hinge is present bilaterally.
However, the actual strength of the remaining posterior arch tissue ("hinge") is not easily assessed. Rotational stability, in the sense that anterior repair alone is sufficient, cannot be safely relied upon. Both anterior and bilateral posterior fixation is therefore recommended for B3 injuries.
2 Sequence of reduction and fixation top
Reduction and fixation of the anterior arch are usually performed first, especially if the pubic symphysis is disrupted. This should improve posterior arch alignment, but ring alignment is not necessarily corrected.
When a posterior injury can readily be reduced and fixed in anatomical alignment, this may be performed as a first step. This will provide a stable well-aligned hemipelvis upon which the rest of the reconstruction can be based.
Provisional internal or external fixation can be used to progressively stabilize the pelvis during reconstruction. This should allow for adjustments as necessary to reduce additional sites of displacement.
3 Preoperative planning top
An explicit, written pre-operative plan is strongly encouraged. The following provides an outline of recommended steps.
Assess and consider:
- Whole patient (physiologic status and other injuries)
- Pelvic region & organ systems (local details of pelvic region including soft tissues and related organ system injuries)
- X-rays and CT scans (reviewed in detail for patients individual anatomy, each injury, and overall pelvic configuration)
Identify and list each individual pelvic ring injury.
For each injury, determine displacement, stability, and a strategy for reduction and fixation (relevant techniques are outlined and discussed below).
List, in order, each step of your planned procedure
Finally review the step-by-step list to:
- Confirm plan
- List equipment and implants
- Consider potential problems and solutions
Share the plan with other members of the operative team – including nursing staff, radiographic technician, and anesthesia staff.
4 Approaches topenlarge
The standard approach to the symphysis is used for its reduction and fixation.
For more lateral exposure of the pubic ramus, a lateral extension of the standard approach or a modified Stoppa approach may be necessary.
For access to an unstable iliac fracture or SI joint, the anterior approach to the iliac wing is necessary.
Special consideration must be given to crescent fractures, for which fixation depends upon the fracture anatomy, leading to possible anterior or posterior ORIF, or percutaneous iliosacral screw fixation.
Pubic ramus intramedullary screws are inserted through stab wounds, either over the pubic tubercle (for retrograde insertion) or laterally over the acetabulum (for antegrade insertion).
The location of the stab wound is found using a C-arm and a K-wire.
For retrograde screw insertion, the surgeon stands on the opposite side of the table from the ramus being fixed.
5 Reduction and fixation topenlarge
Choice of anterior fixation is based upon the individual anterior arch injuries.
Several different techniques of anterior arch fixation are available. Clear indications for one over the other are rarely present.
If a satisfactory reduction of the pubic ramus cannot be obtained closed, open reduction is indicated, in which case fixation can be performed with either a pubic ramus IM screw or plate.
If an external fixator is used for reduction, it is often sufficient for stabilization while a well aligned ramus fracture heals. This may be preferred to avoid an extensive exposure when a complex comminuted ramus fracture is present yet satisfactory aligned.
The Pubic symphysis plating is indicated for symphyseal disruption and/or pubic body fractures.
Posterior fixation may be advisable for one or both of the B3 posterior arch injuries.
Percutaneous iliosacral screw fixation is usually the preferred technique.
In the rare case of a B1 sacral fracture, this should be repaired with an IS Screw, unless it is displaced or associated with neurological deficit.
If available, the use of intraoperative navigation may be beneficial for iliosacral screw fixation.
Larger crescent fractures can be repaired through an anterior (preferred) or posterior approach.
In the exceptional case of an unstable iliac fracture, this should be plated through the anterior approach to the iliac wing.
6 Check of osteosynthesis topenlarge
Check the completed osteosynthesis with Imaging, and physical exam if there is any question about pelvic stability.
Using inlet and outlet views, with the C-arm, confirm that pelvic deformity has been corrected and that involved sacroiliac joints and pubic symphysis are anatomically reduced.
Unless a C-arm with a large field of view is available, it may be wise to obtain similarly oriented portable x-rays of the entire pelvis, to be certain about overall alignment.
Confirm that reduction of each fracture or joint injury is satisfactory, Make sure that all fixation devices are properly placed, and that each screw is of appropriate length. Multiple views are typically needed, including both axial and perpendicular views for questionable screws. If screws protrude from bone, consider risks to nerves, vessels, and adjacent viscera, especially urethra and bladder after pubic symphysis repair.