title: The effect of void creation prior to vertebroplasty on intravertebral pressure and cement distribution in cadaveric spines with simulated metastases.
abstract: BACKGROUND
  For osteoporosis or spinal metastases, percutaneous vertebroplasty is effective in pain relief and improvement of mobility. However, the complication rate (cement extravasation and fat embolisms) is relatively higher in the treatment of spinal metastases. The presence of tumor tissue plays a significant role in intravertebral pressure and cement distribution and thereby affects the occurrence of complications. We investigated the effect of void creation prior to vertebroplasty on intravertebral pressure and cement distribution in spinal metastases.
  
  
  METHODS
  Eighteen vertebrae (T8-L4) from five cadaveric spines were randomly allocated for two groups (group with and without void) of nine vertebrae each. Defect was created by removing a central core of cancellous bone in the vertebral body and then filling it with 30% or 100% fresh muscle paste by volume to simulate void creation or no void creation, respectively. Then, 20% bone cement by volume of the vertebral body was injected into each specimen through a unipedicular approach at a rate of 3 mL/min. The gender of the donor, vertebral body size, bone density, cement volume, and intravertebral pressure were recorded. Then, computed tomography scans and cross sections were taken to evaluate the cement distribution in vertebral bodies.
  
  
  RESULTS
  No significant difference was found between the two groups in terms of the gender of the donor, vertebral body size, bone density, or bone cement volume. The average maximum intravertebral pressure in the group with void creation was significantly lower than that in the group without void creation (1.20 versus 5.09 kPa, P = 0.001). Especially during the filling of void, the difference was more pronounced. Void creation prior to vertebroplasty allowed the bone cement to infiltrate into the lytic defect.
  
  
  CONCLUSIONS
  In vertebroplasty for spinal metastases, void creation produced lower intravertebral pressure and facilitated cement filling. To reduce the occurrence of complication, it may be an alternative to eliminate the tumor tissue to create a void prior to cement injection.
authors.affiliation: Department of Orthopedics, Qilu Hospital, Shandong University, Jinan, Shandong, People's Republic of China. osteolk@163.com.
authors.forename: Ka
authors.initials: K
authors.lastname: Li
authors.affiliation: Department of Orthopedics, Qilu Hospital, Shandong University, Jinan, Shandong, People's Republic of China. yanjun120105@163.com.
authors.forename: Jun
authors.initials: J
authors.lastname: Yan
authors.affiliation: Department of Orthopedics, Qilu Hospital, Shandong University, Jinan, Shandong, People's Republic of China. yangqiang_01@126.com.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Yang
authors.affiliation: Department of Orthopedics, Qilu Hospital, Shandong University, Jinan, Shandong, People's Republic of China. zhenfengli163@163.com.
authors.forename: Zhenfeng
authors.initials: Z
authors.lastname: Li
authors.affiliation: Department of Orthopedics, Qilu Hospital, Shandong University, Jinan, Shandong, People's Republic of China. qlgkjmli@163.com.
authors.forename: Jianmin
authors.initials: J
authors.lastname: Li
mesh_terms: D000368:Aged; D001843:Bone Cements; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011897:Random Allocation; D013125:Spinal Neoplasms / Q000556:secondary* / Q000601:surgery*; D054854:Vertebroplasty / Q000379:methods*
chemical_list: D001843:Bone Cements