Clinical Efficacy of Different Bone Cement Distribution Patterns in Percutaneous Kyphoplasty: A Retrospective Study.

BACKGROUND: Bone cement distribution patterns in percutaneous kyphoplasty (PKP) is the key factor in keeping the vertebral stabilization and curative effect. However, the same cement volume can result in different bone cement distribution patterns and can thereby lead to different clinical outcomes. Therefore we investigated associations between cement distribution patterns and the occurrence rates of recompression in cemented vertebrae after PKP for patients with osteoporotic vertebral compression fractures (OVCFs).

OBJECTIVES: The study focuses attention on the influence of compact and dispersive cement distribution patterns in PKP for patients with OVCFs.

STUDY DESIGN: A retrospective cohort study.

SETTING: An affiliated people's hospital of a university.

METHODS: According to different cement distribution patterns, patients were assigned to 4 groups. The demographic data, radiographic data, and clinical outcomes were compared between the 4 groups. The Visual Analog Scale (VAS) and Oswestry Disability Index (ODI) were evaluated before and 2 days after PKP. Moreover, the relationships between bone cement and clinical outcomes were analyzed. The epidemiologic data, clinical outcomes, and complications of the 4 groups were assessed. Comparisons of the radiologic and clinical results of the 4 groups were made pre- and postoperatively. Anterior height of fractured vertebrae (AH), the kyphotic Cobb angle, and the volumetric cubage index of the fractured vertebrae were measured.

RESULTS: A total of 104 subjects were retrospectively analyzed and followed up (median age, 75.01 ± 8.42 years; age range, 56-94 years). The mean procedure duration was 61.26 ± 23.05 minutes (range, 30-140 minutes). The mean follow-up was 12.1 ± 2.2 months (range, 2-15 months). Statistically, there was no significant difference in terms of gender, age, body mass index, and bone mineral density (P > 0.05). The incidence of cement leakage was significantly lower in group A than those in the other groups. The total amount of bone cement injected into 104 cases (104 vertebral bodies in total) was 848.5 mL, and the amount of bone cement injected into a single vertebral body was 7.94 ± 1.38 mL. The amount of bone cement injection in each group was the lowest (6.80 ± 1.66 mL) in group D, followed by (7.94 ± 1.38 mL) group B, and the highest (8.96 ± 1.68 mL) in group A, with a statistically significant difference between the 4 groups (P < 0.05). No serious complications were observed during the follow-up periods. The AH and Cobb angle improved significantly for the 4 groups (P < 0.05). The VAS score decreased from 3.55 ± 0.54, 3.53 ± 0.65, 3.40 ± 0.58, and 3.40 ± 0.66 preoperatively to 0.18 ± 0.39, 0.23 ± 0.41, 0.20 ± 0.40, and 0.15 ± 0.36 at 48 hours postoperatively. The ODI score dropped from 35.65 ± 4.54, 36.45 ± 4.72, 34.12 ± 4.86, and 35.65 ± 4.34 preoperatively to 15.47 ± 1.32, 15.32 ± 1.34, 15.23 ± 1.26, and 15.73 ± 1.17 at 48 hours postoperatively.

LIMITATIONS: Our estimation of the vertebral body volume is imprecise. In addition, the number of subjects with OVCFs was small in this retrospective study. The volume of the fractured vertebra was not calculated accurately.

CONCLUSIONS: Significant associations between cement distribution patterns and bone cement leakage affected the clinical outcome in patients after PKP. A higher incidence of bone cement leakage was observed in patients with treated vertebrae exhibiting a single-dispersive or single-compact pattern.

KEY WORDS: Percutaneous kyphoplasty, osteoporotic vertebral compression fracture, bone cement distribution patterns.