Radiologic and clinical characteristics of vertebral fractures in multiple myeloma

Abstract

Background context: Nearly 80% of patients with newly diagnosed multiple myeloma (MM) have bony lesions on magnetic resonance imaging (MRI). These lesions may progress to debilitating vertebral fractures. No studies have quantitatively characterized these fractures or identified predictors of fracture burden and severity.

Purpose: The purpose of this study was to characterize the clinical and radiologic features of these fractures and to identify independent predictors of fracture burden and severity.

Study design/setting: A consecutive retrospective chart review was conducted from January 2007 to December 2013 at a single tertiary-care institution.

Patient sample: Patients with diagnoses of both MM and vertebral fracture were included in this study. Those with a history of non-MM vertebral fracture were excluded.

Outcome measures: The primary outcome measure was height loss of the fractured vertebral body, whereas secondary outcome measures included number of fractures and morphology.

Methods: Data were collected at fracture presentation. Radiologic data were obtained from T1-weighted MRI. Anterior, middle, and posterior vertebral body height losses were recorded, and a Genant grading was made. Multivariable Poisson and logistic regression were performed to identify predictors of fracture burden and severity.

Results: Among 50 patients presenting with vertebral fracture, 124 fractures were observed. The majority (76%) of these patients did not have a previous MM diagnosis. The most common presenting symptom was back pain (84%), followed by neurologic (54%) and constitutional (50%) symptoms. The mean anterior, middle, and posterior height losses of the fractured vertebral body were 30%, 37%, and 16%, respectively. Twenty percent of fractures were Genant Grade 1 (mild), whereas 32% and 48% were grades 2 (moderate) and 3 (severe). Fifty-five percent of fractures were biconcave, whereas 32% and 13% were wedge and crush fractures. Lower body mass index and albumin and increased myeloma protein, light chains, and creatinine predicted an increased number of fractures at presentation. Increased β2-microglobulin and creatinine predicted more severe vertebral fractures.

Conclusions: In the present study, 124 fractures were observed among 50 patients. These fractures were generally severe, biconcave, and in the thoracic spine. Laboratory signs of advanced MM predict greater fracture burden and severity. In the future, monitoring of these predictors may raise suspicion for an MM-associated vertebral fracture.

Keywords: Genant grading; Height loss; Imaging; Multiple myeloma; Plasmacytoma; Vertebral fractures.