Comparison Of High-viscosity Cement Venebroplasty And Balloon Kyphoplasty For The Treatment Of Osteoporotic Vertebral Compression Fractures

BackgroundOsteoporosis is a common disease characterized by low bone mass and microarchitectural deterioration of bone tissue, leading to enhanced bone fragility, and consequently increases the risk of fractures. The most common fracture sites involve the spine, hip, or wrist. Osteoporotic vertebral compression fractures (OVCFs) could result in pain, deformity, and low quality of life, which dramatically increase morbidity and mortality.Conservative therapy involves bed rest, pain medication, physiotherapy and bracing. Although most fractures heal within a few weeks or months, about 35% of all patients still have pain and disability that fail to respond to conservative therapy. Therefore, interventions that effectively manage pain and shorten recovery time would be of great benefit.Percutaneous vertebroplasty is a widely used vertebral augmentation procedure for treating osteoporotic vertebral compression fractures (OVCFs). But high cement leakage rate caused by a low-viscosity cement and high injection pressure has limited its general use. Balloon kyphoplasty (BKP) and high-viscosity cement vertebroplasty (HVCV) are two modifications of vertebroplasty designed to decrease cement leakage. Our prospective clinical trial was performed to compare the safety and efficacy of high-viscosity cement vertebroplasty (HVCV) with that of BKP for the treatment of OVCFs in terms of pain, functional capacity, cement leakage and height restoration.ObjectiveTo assess the safety and efficacy of HVCV compared with BKP through a prospective cohort study.1. Clinical Assessment. To compare the differences between HVCV and BKP in the improvement in pain, quality of life after operations and during the follow-up period.2. Radiological Assessment. To compare the differences between HVCV and BKP in the anterior vertebral height restoration after operations and during the follow-up period.3. Complications Evaluation. To compare the differences between HVCV and BKP in the cement leakage, cement emboli, et al after operations.4. Subsequent vertebral fractures. To compare the differences between HVCV and BKP in subsequent vertebral fractures during the follow-up period.Materials and MethodsMethod:This study was designed as a single-center prospective comparison between HVCV and BKP for treating OVCFs, and planned to recruit 100 participants.Before surgery, careful clinical evaluation and radiographical examinations are crucial for patient selection. Magnetic resonance imaging (MRI), thin slice computerized tomography (CT), dual-energy X-ray absorptiometry (DEXA) and anteroposterior(A/P) and lateral radiographs were evaluated before the surgery to determine the appropriateness of the procedure and plan the treated levels. The inclusion criteria were:recent lumber or thoracic vertebral compression fractures (proven by radiographs and MRI) and unsatisfactory pain relief (VAS≥5) after at least 2 to 4-week conventional therapy, a confirmed diagnosis of osteoporosis (proven by DEXA), and ≥50 years of age. Exclusion criteria included burst fractures, infection, radicular syndrome, primary bone tumors, and spinal metastases. Patients randomly underwent either HVCV or BKP. Patients were blinded to which group they were assigned to. The amount of the injected cement was recorded.Pain scores were recorded using Visual Analog Scale (VAS) before the procedure, and at 1 day,3 months,1 year after the procedure. The Oswestry Disability Index (ODI) was compiled to measure patients’ functional disability before the procedure and at 3 months and 1 year after the procedure.Assessment of cement leakage was based on radiographs, supplemented by postoperative CT scans. In addition, the location of leakage was classified as following:(1)disc space, (2)epidural space, (3) paravertebral areas, and (4) peripheral veins.Changes of the anterior vertebral body height preoperatively, postoperatively and at 1 year were calculated on lateral radiographs. Blinded data about cement leakage and vertebral body height were collected by radiologists.Patients who still had refractory pain after operations or incurred another site pain would undergo subsequent radiographs and MRI to determine whether sustaining subsequent vertebral fractures.During the follow-up, any patient who suffered from another new compression fracture was excluded from the assessment of VAS, and ODI scores, who was lost to follow-up was excluded from the assessment of VAS, ODI scores, and vertebral body height.Results107 patients underwent HVCV or BKP on 140 compressed vertebral bodies. Levels treated included T5 to L5. There were no statistically significant differences between the two groups in terms of age, gender, VAS, ODI scores, and compression rate before surgery (P>0.05).Both groups experienced significant pain relief and life quality improvement. In HVCV group, the mean VAS decreased from 8.10±1.23 preoperatively to 2.59±0.76 on the first day postoperatively (P<0.05), and even further to 1.24±0.72 at 3 months and 1.24±0.95 at 1 year (P<0.05), and the respective VAS score for BKP group was 8.04±1.13 preoperatively to 2.54±0.81 on the first day postoperatively (P<0.05), and even further to 1.06±0.68 at 3 months and 1.02±0.80 at 1 year(P<0.05). The mean ODI score of (71.22±10.56)% before the procedure dropped to (19.74±6.44)% at 3 months and (17.04±6.43)% at 1 year (P<0.05) after the procedure (in HVCV group), and from (71.30±10.22)% preoperatively to (19.18±5.89)% postoperatively at 3 months and (16.20±6.70)% at 1 year(P<0.05) (in BKP group). The VAS and ODI scores didn’t changed significantly after 3 months postoperatively. There were no statistically significant differences between the two groups in terms of VAS and ODI scores at the above mentioned times of assessment.The mean injected cement volume was (3.31 ±0.77) mL (range,1.5-5 mL) in HVCV group, which was significantly different from the mean injected cement volume of (4.22±1.29) mL (range,1.7-6.8 mL) in BKP goup (P<0.0001).The mean preoperative compression rate was (34.70±12.78)% in HVCV group and (34.42±12.60)% in BKP group (P=0.90). The mean vertebral height restoration rate was (24.19±16.54)% in HVCV group, (45.05±17.31)% in BKP group. The differences were statistically significant between two groups (P<0.0001). At 1 year follow-up, there was no significant loss of height to be noted for each group (P>0.05).The cement leakage rate was 13.24% in HVCV group, which was lower than 30.56% in BKP group (P<0.05). The cement leakage was observed most commonly into the disc space.No symptomatic cement leakage, neurological deficit or embolism occurred in HVCV group. In BKP group, one patient experienced severe discogenic back pain related to a disc leak and finally underwent discetomy with posterior spinal fusion. The second complication in this group was asymptomatic cement emboli in the right lung related to venous leakage. No mortalities or infections were observed in the two groups.There was 1 case of a new adjacent vertebral fracture in HVCV group (2%), and 4 cases of new nonadjacent vertebral fractures in BKP Group (7.84%). Subsequent fractures were not statistically different between two groups(P=0.18). All new fractures were treated surgically.ConclusionHVCV and BKP are safe and effective in improving the quality of life and relieving pain. HVCV has lower cement leakage rate. For its increasing the safety of vertebroplasty techniques and reducing the number of steps and procedure time, HVCV is recommended for the treatment of OVCFs. BKP is more effective in vertebral height restoration. Subsequent fractures are not different between two groups.