Review Question - QID 215114

This patient is presenting with a nondisplaced zone 1 sacral insufficiency fracture. This injury can be successfully treated with weightbearing as tolerated and physical therapy.

Sacral fragility fractures encompass both atraumatic sacral fractures, as well as sacral fractures that occur as a result of low energy mechanisms in elderly patients with osteopenic bone. Over time, sacral fragility fracture incidence has increased with the aging population. The majority of sacral insufficiency fractures can be treated with weight-bearing as tolerated and physical therapy for gait training (minimally displaced zone 1 and nondisplaced zone 2 fractures). Fractures that are associated with >1 cm of displacement or have neurologic deficits require surgical treatment.

Sanders et al. performed a study to evaluate the effectiveness of transiliac-transsacral screw fixation for the treatment of sacral insufficiency fractures that fail nonoperative treatment. They compared preoperative and postoperative Visual Analog Scale scores and Oswestry Low Back Disability Index scores. They found that patients experienced statistically significant improvement in both outcome measures after intervention and no complications were encountered. They concluded that transiliac-transsacral screw fixation is a safe and effective treatment for sacral insufficiency fractures recalcitrant to nonoperative management.

Rommens et al. propose a novel classification system for fragility fractures of the pelvic ring. The classification is based on morphological criteria and it corresponds to the degree of instability. They hope that this criterion will help guide treatment based on the degree of instability based on radiological and clinical findings.

Figure A is an AP pelvis radiograph demonstrating no osseous abnormalities. Figure B is an axial T1 MRI of the pelvis with a nondisplaced zone 1 sacral fracture.

Incorrect Answers:
Answer 1: Examination under anesthesia is helpful in diagnosing subtle instability patterns that may not be visible with static imaging. However, the injury is minimally displaced which suggests the pelvis ligamentous structures are intact.
Answers 3: Non-weightbearing for this injury is associated with greater patient morbidity. Nondisplaced insufficiency fractures are inherently stable and have a high rate of treatment success with immediate weight-bearing.
Answer 5: Percutaneous posterior pelvic fixation can be used for patients with displaced fractures or who have failed nonoperative treatment.