Objective: This study aimed to compare the relationship of pain relief with the amount and distribution of injected cement in kyphoplasty for osteoporotic vertebral fractures.

Patients and methods: This cohort study was conducted on 90 patients with osteoporotic vertebral fractures who needed chronic pain medication. Patients underwent kyphoplasty balloon surgery, and polymethylmethacrylate (PMMA) or bone cement was injected into the created cavities and the volume of injected cement was recorded. After the surgery, the distribution of cement was measured using a computed tomography (CT) scan in the coronal, sagittal, and axial axes of the vertebra, and the percentage of cement distribution was evaluated using Photoshop software in these three axes, followed by the pattern of cement distribution. The cement was measured in the entire vertebra. The patients were evaluated over a period of 6 months, and the amount of pain improvement was measured by the VAS scale in 24 hours, two weeks, six weeks, and six months after surgery. In this study, the data of 90 patients with a mean age of 72.5±10.9 years were included in the study. The mean volume of cement injected was 1.2±5.8 cc, followed by the mean percentage of cement distribution (47.7±7.4%); the mean pain score before the operation (8.7±1.3), the mean pain score 24 hours after the operation (7.7±1.4), the mean pain score 2 weeks after the operation (4.8±1.3), the mean pain score 6 weeks after the operation (3.6±1.2) and the mean pain score 6 months after the operation (3.5±1.4) were evaluated after collection.

Results: The pain intensity 24 hours after the operation had a significant positive correlation with the percentage of cement distribution and pain intensity before the operation. The intensity of pain 2 weeks after the operation was positively correlated with the age of the patients and the intensity of pain before the operation. The pain intensity 6 weeks after the operation was significantly correlated with the age of the patients and the pain intensity before the operation. The intensity of pain 6 months after the operation was positively linked to the age of the patients and negatively correlated with the percentage of cement distribution. The pain reduction has changed significantly in the 4 measured intervals, and during a period of 6 months, there was a significant improvement in the pain level of the patients continuously. It was found that the rate of recovery of the patient’s pain has increased by increased distribution of injected cement. Although this reduction in pain during the 6-month period was not significantly related to the variables of gender, smoking, history of corticosteroid use, and the volume of injected cement.

Conclusions: The balloon kyphoplasty is a safe and successful method for treating symptomatic vertebral fractures. Kyphoplasty is associated with significant pain relief, improved quality of life, and kyphosis correction. The volume of cement injected had no effect on reducing patients’ pain after the operation, but a higher percentage of cement distribution was associated with a better response in patients.