Improved biomechanics of two alternative kyphoplasty cementation methods limit vertebral recollapse

Abstract

The clinical efficacy of vertebral cement augmentation for compression fractures (VCFs) remains undetermined. Recent studies have shown that refracture and progression of deformity may occur after augmentation with significant clinical consequences. Vertebral body height loss following kyphoplasty has also been observed with cyclic loading. We hypothesized that height loss is partly due to lack of cement fill past the margin of cancellous bone created by balloon expansion with subsequent failure under load. The biomechanical characteristics of two alternative cementation techniques were compared to standard kyphoplasty in cyclically loaded cadaveric VCF constructs. Sectioned osteoporotic thoracolumbar cadaveric spines were compressed to 75% of anterior vertebral height. Specimens were then allocated to standard kyphoplasty, balloon pressurization (BP), with reinflation of the balloon after 50% cement injection, or endplate post (EP), with perforation of the cavity rim using an articulating curette prior to injection. Following cementation, each specimen was preconditioned and loaded over 100,000 cycles. All techniques improved vertebral height (p's < 0.005). The EP and BP techniques provided greater cement fill than the standard technique (p's ≤ 0.01). Normalized vertebral height loss following 100,000 cycles was reduced with the EP technique versus standard kyphoplasty (p < 0.04). Height loss was inversely correlated with cement fill (p < 0.03). No vertebral recollapse occurred with the EP technique in blinded radiographic analysis. Statement of clinical significance: The EP technique demonstrated improved biomechanical characteristics versus the standard technique in cadaveric osteoporotic VCF constructs with decreased recollapse following cementation. This technique may have increased efficacy in cases when kyphoplasty more substantially improves vertebral body height. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res.

Should kyphoplasty curettes be used in nonosteoporotic patients? A cautionary tale

“…This is especially relevant for fractures affecting the posterior wall of the vertebral body or in patients with tumoral lesions in the verrtebral body. Additionally, a recent biomechanical study revealed that using a curette before balloon kyphoplasty may reduce the rates of vertebral height loss after kyphoplasty, which could have been related to a lack of cement interdigitation with the cancellous bone of the vertebral body adjacent to the cavity created by the balloon in the noncurette group . This study also demonstrated greater filling of the vertebral bodies by cement in the curette group, a difference that reached statistical significance.…”