Sacral Insufficiency Fractures: Recognition and Treatment in Patients with Concurrent Lumbar Vertebral Compression Fractures

Introduction: In reviewing a larger group of osteoporotic vertebral compression fractures (VCFs), we found that the overall incidence of sacral insufficiency fractures (SIFs) is higher than commonly reported values. This is especially seen in patients with previous or concurrent lumbar VCFs and also in a subgroup that had lumbar stenosis or hip arthroplasty. The altered biomechanics due to associated lumbar stenosis or hip arthroplasty lead to increased mechanical stress on already weakened and deficient sacral alae, which are more vulnerable to osteoporotic weakening than other parts of the sacrum.

Materials & Methods: We studied an overall population of patients with VCF seen clinically and separated the patients into the following groups: patients not previously treated, patients treated with vertebroplasty or kyphoplasty at one or more levels, and patients diagnosed with sacral fractures and treated with vertebroplasty or kyphoplasty. We wanted to see if a pattern existed among the patients who had sacral symptoms, were diagnosed with sacral insufficiency fractures, and subsequently underwent sacroplasty.

Results: In a review of 79 consecutive patients, over a 24-month period, with VCF who underwent surgical treatment, there were 10 patients who also had sacral insufficiency fractures. Four of the patients had sacral insufficiency fractures without VCF. None of the patients with sacral insufficiency fractures were on treatment for osteoporosis at the time of diagnosis. The following symptoms indicated SIF: lower sacral pain (n = 10), buttock pain (n = 7), lateral hip pain (n = 5), and groin pain radiating to the thigh (n = 4). The average time to diagnose SIF was two months after the onset of pain.

Conclusions: Sacral insufficiency fractures are a frequent cause of both acute and chronic pain; however, they are often missed by the majority of physicians. The frequency of undetected sacral fractures is high. This is due to a number of potential pitfalls, which include both subjective and objective reasons: the patient presenting with vague symptoms, the physician only performing a physical examination of the lumbar spine, and the physician ordering the inadequate standard lumbosacral radiographs, computed tomography (CT), or magnetic resonance imaging (MRI), as well as automatically relating the pain and other symptoms to preexisting MRI findings that are very commonly found in the elderly population. All of these pitfalls lead to SIFs being overlooked.