Quantitative Volumetry of Cement Leakage in Viscosity-controlled Vertebroplasty

STUDY DESIGN: This study was designed as a cohort study comparing a prospective sample to a historic control group. OBJECTIVE: The aim of the actual trial was to compare the rate of cement leakage by quantitative volumetry comparing viscosity-controlled and non-viscosity-controlled vertebroplasty. SUMMARY OF BACKGROUND DATA: Percutaneous vertebroplasty (PVP) is a widespread safe and effective technique in the treatment of osteoporotic compression fractures and vertebral metastatic lesions. However, cement leakage has been identified as a problem of this technique. The leakage rates are reported to range from 7% to 90%. The main influence factor for leakage has been demonstrated to be cement viscosity. Assessment of appropriate injection viscosity is highly subjective and observer dependent. Viscosity-controlled vertebroplasty (Vertecem system) has been developed to objectively measure cement viscosity before injection. It introduces a viscosimeter to measure the actual cement viscosity before injection into the vertebra, and therefore may prevent leakages resulting from low-viscosity cement injections. Despite more than 800 Pubmed citations on PVP, there is only 1 report on distinct measurement of cement leakage by semiquantitative volumetry. METHODS: A total of 111 vertebrae in 68 patients, in which PVP was performed for osteoporotic fractures, were included. Thirty-seven patients (76 operated vertebrae) were assessed prospectively using the viscosity-controlled vertebroplasty. The results were compared with a retrospective group of 31 patients (35 operated vertebrae) undergoing PVP without using a viscosimeter. RESULTS: : There were no significant differences between the 2 groups in the applied volume of cement per fractured vertebra (P=0.73). The frequency of cement leakage in viscosimete-assisted vertebroplasty was 42.1% and 58.3% in the historic group. Cement leakage into the basivertebral vein (type B), was detected in 6.6% with and in 11.1% without viscosimetry. CONCLUSIONS: The use of viscosity-controlled vertebroplasty led to a decrease in the leakage rate from 58.3% to 42.1%. Leakage into the basivertebral vein with the risk of compression of nerval structures was reduced to almost 50% when viscosimetry was performed. It revealed to be a helpful tool for more unexperienced surgeons to assess the appropriate viscosity for vertebroplasty.