Introduction: The PMMA amount to be injected during vertebroplasty mainly depends on the level and vertebral body dimensions to be treated, fracture pattern, intraoperative complications (leakage) and ultimately on the surgeon’s judgment. Studies indicating a relation between intravertebral cement volume and pain relief are still insufficient and an optimal value of cement volume for this treatment is still unknown. This analysis aims to determine the minimal bone cement volume that is required to reduce pain after vertebroplasty.

Methods: We analyzed 31 cases of lumbar vertebral fracture treated with percutaneous bipeduncolar vertebroplasty with PMMA. Depending on the volume of PMMA that was injected, patients have been divided in three groups: group A (9 patients): more than 4 mL; group B (13 patients): 3 to 4 mL; group C (9 patients): less than 3 mL. Post-operative pain has been determined through Visual Analogue Scale (VAS) within 24 hours after surgery. All patients underwent lumbar plain radiograph 40 days after surgery to evaluate biomechanical outcome.

Results: VAS scores decreased by more than 3 points in 8 patients belonging to group A (88%), 12 patients belonging to group B (92,3%), 5 patients belonging to group C (55,5%). The outcome of the chi-square test hasn’t highlighted any difference (on a statistical level) between groups A and B nor between groups B and C. However, considering groups A and B as a whole, there is a significant difference compared to group C (chi-square 4,80; p 0,0284; OR 0,13; probability 5%).

Conclusions: Despite the limited number of cases we analyzed and the retrospective nature of our study, we believe that 3mL could be considered the lower limit of PMMA volume to be injected during vertebroplasty to obtain a substantial reduction of pain in lumbar vertebral fractures.

Patient Care: Injecting the correct quantity of PMMA during a kyphoplasty means complication rate reduction with good clinical (pain and mechanical) outcome.

Learning Objectives: By the conclusion of this session, participants should be able to identify the correct quantity of bone cement offering the best clinical outcome with minimal complications rate.

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