Augmentation of transpedicular screws by intraoperative vertebroplasty

Abstract

Background and purpose

The aim of the study was to determine the efficacy of posterior spinal stabilization, combined with intraoperative vertebroplasty defined as intraoperative filling of instrumented vertebral bodies (VB) with polymethylmethacrylate (PMMA).

Material and methods

Seventeen patients with osteoporosis or osteopenia underwent posterior spinal fusions. The surgical procedures included laminectomy, spondylodesis, insertion of pedicular screws, intraoperative vertebroplasty and correction of spinal deformity.

Results

Postoperative assessment showed improvement of pain in all cases. Motor deficit regressed in 2 of 3 afflicted patients. In 12 vertebrae (27.3%), the mass of PMMA extended from one endplate to another, filling 100% of VB height, in 7 (15.9%) it filled 90–99%, in 14 (31.8%) 80–89%, in 9 (20.4%) 70–79%, and in 2 (4.5%) it filled 50–60% of VB height. In the horizontal plane, PMMA filled central parts of 72.7% of vertebral bodies. PMMA completely surrounded 68.9% of screws, and partially surrounded 18.4% of screws, whereas 12.6% of screws had no contact with cement mass. Spinal stabilization reduced kyphotic deformity in 15 patients (range of reduction: 6°-25°; mean: 13.6°). During follow-up (3–32 months; mean: 16) implants of 11 patients were stable, 1 implant instability was diagnosed 7 months after surgery, 5 patients were lost to follow-up. Asymptomatic cement leaks occurred in 45% of vertebrae.

Conclusions

Intraoperative vertebroplasty performed after insertion of pedicular screws may be considered as a technical variation useful to stabilize osteoporotic spines. After PMMA hardening, intraoperative manoeuvres to correct spinal deformity were possible without any damage of instrumented vertebrae.