Kyphoplasty versus vertebroplasty cement extravasation and outcomes in patients with metastatic spinal disease

Abstract

Introduction: Over 1 million individuals in the US demonstrate symptomatic spinal metastasis, resulting in disability and decreased quality of life. Kyphoplasty and vertebroplasty are safe and effective treatments for painful metastatic spinal lesions; however, cement extravasation is a common occurrence with limited outcomes data previously reported. This study compares the incidence of cement extravasation in patients with metastatic spinal disease following kyphoplasty versus vertebroplasty procedures. Furthermore, we compare post-operative outcomes. Materials and Methods: All patients undergoing vertebroplasty and kyphoplasty in a 5 year period at a single institution were identified. Patients age 18-89 years who underwent kyphoplasty and vertebroplasty with a diagnosis of metastatic spinal disease were included. Prisoners and pregnant women were excluded. 21 patients who underwent kyphoplasty and 91 patients who underwent vertebroplasty were identified. Chi-Square and t-tests were performed. P=0.05 was used for significance. Results: The mean age of the patients undergoing vertebroplasty and kyphoplasty was 71±12.1 and 60±17.8 years, respectively. Patients who underwent kyphoplasty had a higher volume of cement injected, 4.33±0.91 cc’s versus 3.85±0.61 cc’s in vertebroplasty patients. 4 of 21 patients who underwent kyphoplasty had cement extravasation versus 4 of 91 vertebroplasty patients (p=0.02). In all cases, the cement extravasation was either anterior or into the disc space and did not cause any adverse neurovascular effects. In all 4 patients undergoing vertebroplasty with extravasation, the cement was methylmethacrylate (p=0.01). In patients undergoing kyphoplasty with extravasation, the cement was methylmethacrylate in 3 of 4 patients and high viscosity bone cement in 1 of 4 patients (p=0.22). There was no significant difference in patient’s pre-operative and post-operative ECOG scores, neurologic status, narcotic use, or ambulation status comparing independent versus assisted. However, patients who underwent kyphoplasty had a significantly greater decrease in mean pain score from pre-operative to 12 months post-operatively versus vertebroplasty with mean change scores of 7.4±1.8 and 3.9±3.4, respectively (p=0.03). Conclusion: Patients undergoing kyphoplasty are significantly more likely to have cement extravasation compared to vertebroplasty; however, these patients also had a higher volume of cement injected and experienced a significantly greater decrease in mean pain score at 12 months post-operatively. Furthermore, all extravasations were radiographic in nature and not clinically relevant. The authors believe that limited cement extravasation into the disc space may aid in fracture stability and be beneficial to pain control.