A lumbar compression fracture involves the lumbar vertebrae and occurs typically secondary to bone demineralization. It is seen in postmenopausal women and in the elderly due to osteoporosis but may also be associated with malignancies. Therefore a thorough workup is essential to detect the fracture and its cause.
Although compression fractures can occur anywhere along the vertebral column, they are most common at the thoracolumbar junction involving the T8-T12, L1, and L4 vertebrae [1]. The incidence of this condition increases steadily with advancing age [2]. Lumbar compression fractures can be asymptomatic and may be detected incidentally in the elderly on lumbar X-rays or may present insidiously with a backache. The pain is typically in the midline, aching or stabbing in quality, non-radiating and severe enough to cause disability and interfere with activities of daily living. The pain is usually relieved by lying supine and is aggravated by standing or walking. The pain often persists even after the fracture has healed [3]. However young adults with lumbar compression fractures may be diagnosed with a severe back pain of sudden onset and neurologic deficits in the lower limbs following a vehicular accident. The incidence of associated radiculopathy increases with descending spinal levels [4]. In the elderly, multiple fractures over a period of time lead to decrease in height and stature with subsequent paraspinal muscle shortening, lumbar lordosis, and thoracic kyphosis. As a result, the individual has to actively contract the paraspinal muscles to maintain posture leading to fatigue and in severe cases, it can lead to impaired lung function, abdominal protuberance, compression of abdominal organs with early satiety and loss of weight [5].
Individuals with lumbar compression fractures secondary to malignancies like multiple myeloma or metastasis may present with fever of unknown origin, night sweats, anorexia, weight loss or a history of a previous breast or prostate malignancy.
Lumbar compression fracture should be suspected in postmenopausal women and the elderly who present with sudden onset severe lumbar pain. Many patients may remember a specific injury [6] although the condition may present without any prior history of trauma. Tenderness is typically elicited on palpating directly over the fracture site and there may also be kyphosis [7]. A thorough neurological examination is necessary but may not reveal any deficits in uncomplicated fractures.
Plain X-rays of the spine will confirm the diagnosis and reveal the classic wedge deformity corresponding to the site of maximum tenderness. A reduction in vertebral height by 20% or a decrease of at least 4 mm compared to the baseline height is an indication of a compression fracture [6]. Ideally, the entire spine should be imaged to exclude multiple fractures and occasionally serial imaging may be required to detect the fracture.
Techniques like computed tomography (CT), magnetic resonance imaging (MRI) help in diagnosis by excluding the other etiologies of back pain. They also confirm the integrity of the posterior vertebral wall [8]. In addition, a CT can detect a compression fracture (not visualized on plain radiographs), spinal canal narrowing and differentiate between a compression fracture and a burst fracture. An MRI is indicated in patients with neurologic deficits, or if a malignancy is suspected as the underlying cause of the lumbar compression fracture. Positron emission tomography (PET) can also be ordered to differentiate between compression fractures of benign versus malignant etiology.
Laboratory tests like erythrocyte sedimentation rate, complete blood count (CBC), prostate-specific antigen testing, serum protein electrophoresis to exclude multiple myeloma and urinalysis for Bence-Jones proteins should be routinely performed. Bone density scanning is recommended to measure the severity of osteoporosis and for further patient management [9].