Effect of Bone Cement Viscosity on Leakage and Outcomes in Vertebroplasty

Summary

This study presents a randomized clinical protocol for percutaneous vertebroplasty in elderly patients with single-level acute osteoporotic vertebral compression fractures, highlighting standardized use of high- versus low-viscosity bone cement and CT-based assessment of cement leakage, pain, function, and radiographic outcomes.

Abstract

Percutaneous vertebroplasty provides rapid pain relief in elderly patients with acute osteoporotic vertebral compression fractures; however, bone cement leakage remains a major safety concern, and the influence of cement viscosity on leakage and clinical outcomes is not fully established. This study evaluated whether high-viscosity cement reduces leakage without compromising efficacy or safety. In this single-center, prospective randomized controlled trial, 184 elderly patients with single-level acute osteoporotic vertebral compression fractures were enrolled and followed for 12 months. Traumatic burst fractures and cases with posterior wall cortical disruption causing >25% spinal canal compromise were excluded. Participants were randomized 1:1 to receive high- or low-viscosity bone cement. The primary outcome was overall cement leakage at 48 h postoperatively, assessed by computed tomography and classified using the Yeom system. Secondary outcomes included pain (Visual Analog Scale), function (Oswestry Disability Index), radiographic parameters, perioperative variables, and adverse events. High-viscosity cement significantly reduced the overall leakage rate compared with low-viscosity cement (RR 0.47, 95% CI 0.29–0.78; adjusted OR 0.36, 95% CI 0.19–0.71; P = 0.003), with consistent results in sensitivity analyses. Leakage patterns differed between groups, with C-type leakage more frequent in the high-viscosity group and B-type leakage more frequent in the low-viscosity group (P = 0.008). Pain and functional outcomes improved significantly in both groups, with no between-group differences over time (all P > 0.05). Radiographic correction, perioperative parameters, and adverse event rates were comparable. Image interpretation reliability was high (κ = 0.86; ICC > 0.90). High-viscosity bone cement reduces early leakage while maintaining comparable clinical and radiographic outcomes, supporting its use as a preferred option in vertebroplasty for this population.

Introduction

Osteoporotic vertebral compression fractures are common spinal fragility fractures in the elderly, which can lead to persistent low back pain, restricted mobility, and decreased quality of life, and significantly increase the risks of falls, prolonged bed rest, and death^1,2. Because it is minimally invasive and provides rapid analgesia, percutaneous vertebroplasty has become an important treatment for elderly patients with acute osteoporotic vertebral compression fractures³. However, bone cement leakage is not uncommon; among these, venous-type leakage and severe leakage into the spinal....

Protocol

The protocol was approved by the institutional ethics committee. The trial was registered with the Chinese Clinical Trial Registry (ChiCTR2200056512). All patients provided written informed consent. During the study, patients’ personal information was de-identified and encrypted, and was accessible only to authorized members of the research team.

Study design

This was a single-center, prospective, randomized, parallel-controlled clinical study comparing the incidence and severity of cement leakage between high-viscosity and low-viscosity medical polymethyl methacrylate (PMMA) bone cement in....

Results

Participant enrollment and baseline characteristics

A total of 314 elderly patients with acute OVCF were assessed; 130 were excluded, and 184 were randomly assigned to the high-viscosity and low-viscosity groups, with 92 in each group. The proportions receiving the assigned intervention were both >97%, the completion rates of 48 h postoperative CT were both >97%, and the 12-month follow-up rates were both >91%, indicating that overall enrollment and follow-up implemen.......

Discussion

High-viscosity bone cement showed a markedly lower overall leakage risk than low-viscosity bone cement on early postoperative CT assessment. After handling missing CTs using worst-case and best-case assumptions, the trend of reduced relative risk remained consistent, indicating that the effect of leakage control was relatively stable. Among cases with leakage, Type C leakage via a cortical defect predominated in the high-viscosity group, whereas Type B venous-type leakage via the intravertebral venous route was more comm.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Alendronate sodium tablets 70 mg	Hangzhou Minsheng-Binjiang Pharmaceutical Co., Ltd.	H20203221	Alendronate sodium 70 mg tablets; approved by the China NMPA; taken once weekly as standard anti-osteoporosis therapy in elderly patients.
Bone biopsy needle set, 11G (for vertebral access)	IZI Medical Products	G36211 / DBBN-11-10.0-M2-S	Osteo-Site Murphy M2-S bone biopsy needle set; outer cannula 11G × 10 cm, inner biopsy needle 14G × 17.1 cm; used for vertebral body access, biopsy and cement injection in vertebroplasty/kyphoplasty.
Bone cement injector, Dual Speed	Stryker Corporation	0206-600-000	Dual Speed Cement Injector; screw-driven injector commonly used with PMMA bone cement for controlled, low-speed continuous injection during vertebroplasty.
C-arm fluoroscopy system, PLX7100A	Nanjing Perlove Medical Equipment Co., Ltd.	PLX7100A	PLX7100A HF Mobile Digital C-arm system; mobile C-arm widely used in Chinese orthopaedic and spine surgery for intraoperative fluoroscopic guidance.
CT scanner, SOMATOM Definition AS 64	Siemens Healthineers	SOMATOM Definition AS 64	64-slice multi-detector CT scanner; widely used for spine imaging, including preoperative assessment of posterior wall integrity and postoperative thin-slice evaluation of cement leakage.
DXA system, Hologic Discovery Wi	Hologic, Inc.	Discovery Wi	Dual-energy X-ray absorptiometry (DXA) system from Hologic Discovery series; Discovery A / Wi / W models are widely used for bone mineral density assessment in multi-center studies and hospitals in China.
High-viscosity PMMA bone cement, VertaPlex HV	Stryker Corporation	0406-622-015	VertaPlex HV radiopaque bone cement; high-viscosity PMMA cement developed for vertebral compression fractures, with immediate thick viscosity after mixing and working time ~18 min; single pack code 0406-622-015 is listed for VertaPlex HV.
Low-viscosity PMMA bone cement, VertaPlex	Stryker Corporation	0406-402-000	VertaPlex bone cement; PMMA cement designed for low initial viscosity and increased working time (~20 min), suitable for multilevel vertebral augmentation; 0406-402-000 is the 20 g twin pack (half-dose) VertaPlex bone cement.
MRI system, Magnetom Avanto 1.5T	Siemens Healthineers	Magnetom Avanto 1.5T	1.5T superconducting MRI system widely installed in large hospitals; supports STIR sequences for detecting acute vertebral bone marrow edema in osteoporotic compression fractures.
Patient monitor, Mindray PM9000	Shenzhen Mindray Bio-Medical Electronics Co., Ltd.	PM9000	Multi-parameter bedside monitor (blood pressure, heart rate, SpO2, respiration, etc.); Mindray PM9000 is widely used in Chinese operating rooms and was specifically reported for monitoring during fentanyl-based sedation in Chinese clinical studies.
Propofol medium and long chain fat emulsion injection (10 mg/mL, 20 mL: 0.2 g)	Haisco Pharmaceutical Group Co., Ltd.	N/A	Propofol Medium and Long Chain Fat Emulsion Injection 20 mL: 0.2 g, manufactured by Haisco; generic propofol MCT/LCT emulsion widely used in China for intravenous sedation and anesthesia. Product and manufacturer are documented in a registered clinical trial from China.
Vacuum bone cement mixing and delivery system	Zimmer Biomet	414701	Zimmer Biomet Vacuum Bone Cement Mixing & Delivery System; closed vacuum mixer and delivery kit for PMMA cement, reducing porosity and operator exposure; commonly used in arthroplasty and vertebral augmentation.