INTRODUCTION
Injectable magnesium-based bone void fillers (IMBVF) has recently been developed to treat insufficiency fractures in the pelvis and the extremities by stimulating bone repair. It also acts as an adjunct to conventional orthopaedic constructions, providing temporary support while promoting bone mineralization. IMBVP for use within the spine has not been investigated. This study aims to review the use of IMBVP in the spine and evaluate its outcomes.
METHODS
All patients who were surgically treated with IMBVF for spinal pathology at a single tertiary institution was retrospectively reviewed. Data collected included diagnosis, patient biodata, number of spinal levels treated with IMBVF, operation duration, blood loss, intraoperative complications, postoperative disposition, duration of hospitalization, discharge disposition, and postoperative complications including wound complications, extravasation, implant loosening, neurological deficit.
RESULTS
A total of 46 spinal levels were treated in 12 patients: 8 levels for osteoporotic compression fractures, 7 levels for spondylolisthesis, 19 levels for degenerative scoliosis, 1 level for lateral recess stenosis and facet arthrosis, 7 levels of adjacent segment disease (ASD) and 4 levels of metastatic spine disease with cord compression. One patient (3 levels) had intraoperative transient bradycardia with labile blood pressure, and subsequent postoperative hypotension in the post-anaesthesia care unit. Four patients (9, 2, 4, 4 levels respectively) demonstrated intraoperative hypotension, of which one (4 levels) progressed to pulseless electrical activity and acute kidney injury with concomitant hypermagnesemia, requiring transfer to the intensive care unit (ICU) postoperatively. No other patients required ICU care. The average length of inpatient stay was 6.9 ± 5.1 days, with 8 patients requiring further step-down care at the community hospital for 14.6 ± 12.7 days. At early follow up visits, none of the patients had cement extravasation and were all ambulant. One patient treated for ASD had mild L4 screw loosening but was asymptomatic.
DISCUSSION
IMBVF in spinal instrumentation has demonstrated good radiological and neurological outcomes at early follow-up, although intraoperative complications (5 patients, 41.7%) such as hypotension were noted. The mechanism of these complications merits further study.