Pathologic sternal involvement is a potential risk factor for severe sagittal plane deformity in multiple myeloma with concomitant thoracic fractures

Abstract

Background context: Skeletal involvement is observed in almost 80% of patients presenting with symptomatic multiple myeloma (MM). The vertebral column is the most frequently affected site by myeloma-induced osteoporosis, osteolysis, and compression fractures. Multiple pathologic compression fractures can lead to significant spinal deformity, which is often considered for complex reconstruction because of the poor quality of life for the affected patients.

Purpose: This study aimed to compare the clinical and radiological outcomes of two groups of MM patients; the first group had thoracic spine fractures and a concomitant pathologic sternal fracture (SF), and the second group had thoracic fractures but no sternal fracture (NSF).

Study design: This was a cross-sectional study.

Patient sample: The sample comprised 98 consecutive patients (n=98) with symptomatic MM and concomitant pathologic thoracic spine fractures over a 3-year period at a national tertiary referral center for the management of MM with spinal involvement.

Outcome measures: Clinical outcome measures used included European Quality of Life-5 Dimensions (EQ-5D), Oswestry Disability Index (ODI), and visual analogue scale (VAS) pain score.

Methods: All consecutive patients with MM were enrolled. The cohort was split into two patient groups: patients with SFs (SF group) and patients without sternal fractures (NSF group). Clinical, serologic, and pathologic variables, radiological findings, treatment strategies, and outcome measures were collected.

Results: The SF group was younger (58±13 years vs. 66±11 years [p=.008]) when compared with the NSF group. The SF group presented with a greater thoracic kyphosis (73°±18° vs. 53°±17.5° [p=.005]), similar VAS pain scores (50.6±22.1 vs. 54.4±22.5 [p>.05]), but poorer EQ-5D (0.24±0.13 vs. 0.48±0.23 [p<.001]) score and ODI (60.6±10.3 vs. 48.2±17.8 [p=.013]) when compared with the NSF group.

Conclusions: Pathologic SF in an MM patient with thoracic compression fractures is a potential risk factor for the development of a severe thoracic kyphotic deformity and sagittal malalignment. This has been demonstrated in this study to be associated with a very poor health-related quality of life. A greater awareness of sternal myeloma disease is needed at presentation (the time of the primary survey) so that SFs can be potentially avoided, thereby preventing progression to a severe kyphotic deformity.

Keywords: Kyphosis; Multiple myeloma; Sagittal plane; Spinal deformity; Sternum; Thoracic fractures.