Kyphoplasty versus percutaneous posterior instrumentation for osteoporotic vertebral fractures with posterior wall injury: a propensity score matched cohort study

Abstract

Background: Osteoporotic vertebral fractures (OVFs) that present with posterior wall cortical injury pose a higher risk for instability. Surgical management includes standard cement augmentation techniques like balloon kyphoplasty (BKP) or percutaneous posterior instrumentation with pedicle screws (PS) or both. Neither treatment has yet demonstrated superiority, and posterior cement leakage is of special concern in these fractures.

Methods: At a single tertiary care center, 25 patients with 32 OVFs with posterior wall injury treated with percutaneous instrumentation and cement augmentation (PS group) were retrospectively included and matched (1:1) using propensity scores to 25 patients with 29 OVFs with posterior wall injury treated with standalone BKP (BKP group) from 2010 to 2018. Our primary study aim identified 30-day morbidity rates using a 4-point grading system by comparing BKP with and without percutaneous instrumentation with PS for the treatment of OVFs with posterior wall injury. Our secondary aims evaluated cement leakage, radiographic results, surgical time, length of stay (LOS), pain relief, and subsequent fractures.

Results: Overall 30-day morbidity was 34% and did not differ between groups (24% BKP vs. 44% PS groups, P=0.136). Most complications were mild (82.4%), requiring no interventions beyond drug treatment. In the PS group, a trend towards more mild complications was observed (16% vs. 40%, P=0.059). Moderate and severe complications affected 17.6% of all morbidity cases and were comparable between groups. Asymptomatic cement leakage into the spinal canal was noted in 2 (8%) BKP patients and symptomatic pulmonary cement embolism in 1 (4.8%) PS patient. Compared with baseline, all radiographic parameters significantly improved in both groups. In the BKP group, mean surgical times (52±32.9 vs. 164.9±48.4 minutes, P<0.001) and LOS (4.3±2.5 vs. 7±2.9 days, P<0.001) were significantly shorter, and use of opioids at discharge was significantly lower (52% vs. 84%, P=0.015). At 3-month follow-up, no differences between groups were seen in back pain, use of opioids, and occurrence of subsequent OVFs. Follow-up averaged 8.4 months.

Conclusions: Standalone BKP may be a viable option for the treatment of OVFs even in the presence of posterior wall cortical injury.

Keywords: Osteoporosis; cement augmentation; kyphoplasty; posterior wall injury; vertebral fracture.

Figure 1

Preoperative and postoperative imaging of an 86-year-old male with an osteoporotic vertebral fracture of L1 who underwent percutaneous instrumentation and cement augmentation techniques (PS group). (A) Preoperative sagittal computed tomography imaging showing posterior wall injury and an intravertebral cleft with vacuum phenomenon; (B) preoperative lateral standing radiograph showing severe kyphotic deformity of the thoracolumbar junction and significantly decreased anterior vertebral height of L1; (C) postoperative anteroposterior standing radiograph after percutaneous instrumentation with cement augmented pedicle screws two levels above and two levels below L1 and balloon kyphoplasty of L1; cardiac pacemaker electrodes are overlapping with T11 and T12; (D) postoperative lateral standing radiograph showing good correction of kyphotic deformity, restoration of vertebral body height, adequate cement augmentation of L1 and pedicle screws, and no signs of posterior cement leakage.

Figure 2

Preoperative and postoperative imaging of a 91-year-old female with an osteoporotic vertebral fracture of L4 who underwent balloon kyphoplasty (BKP group) shows older fractures of L1 and L2. (A) Preoperative sagittal computed tomography imaging showing posterior wall injury and a pincer-type injury in the posterior third of the vertebral body; (B) preoperative lateral standing radiograph showing anterior and posterior vertebral body height loss; (C) postoperative anteroposterior standing radiograph; (D) postoperative lateral standing radiograph showing good restoration of vertebral body height, and no signs of posterior cement leakage.

Figure 3

Preoperative and postoperative sagittal Cobb angle (°) in both study groups.

Figure 4

Preoperative and postoperative vertebral wedge angle (°) in both study groups.

Figure 5

Preoperative and postoperative anterior vertebral height (mm) in both study groups.