Effects of Facetectomy and Crosslink Augmentation on Motion Segment Flexibility in Posterior Lumbar Interbody Fusion

Abstract

Facetectomy causes a nominal increase in ROM and NZ in FE and LB, which are not affected by the addition of a crosslink. Although the effect of facetectomy is greater in AR-and crosslink has a measurable restoring effect-all differences are within a few tenths of a degree under this loading paradigm. Thus, the clinical utility of adding a crosslink may not be justified based on these small biomechanical changes. COM can serve as a complement to ROM and NZ, or even as a surrogate when its 2 components are reported together, as it shows strong agreement with ROM, effectively distinguishes between lax and elastic region behaviors, and provides a measure of flexibility independent of the load range.

The effect of pulsed jet lavage in vertebroplasty on injection forces of PMMA bone cement: an animal study

“…The irrigation liquid together with the removed fat and bone marrow was retrieved through the vacuum biopsy needle during the irrigation process. The technical aspects of the lavage procedure are described in detail in Benneker et al [7].…”

“…In addition to the parameters related to cardiovascular reaction, the cement injection was also quantified using an instrumented syringe holder to collect data on injection force and injection speed. Overall purpose of the studies [7,15] involving the lavage technique in the conventional vertebroplasty procedure was to evaluate the clinical relevance of this new technique. Clinical relevance could be achieved if the use of the lavage technique is accompanied by a lower risk of fat embolism, reduced injection forces and controlled, uniform distribution patterns of the injected cement inside the vertebral body.…”

“…An in vitro study [7], using human cadaveric lumbar and thoracic vertebrae, showed that the lavage technique leads to a reduction of cement injection forces compared to the conventional treatment. Reduction of the injection force is thought to be due to the reduced flow resistance after intertrabecular bone marrow removal.…”

“…Both issues, cement leakage and fat embolism, are addressed by a recently developed lavage technique [7], which enables the surgeon to wash out the intertrabecular bone marrow of the vertebrae before cement injection. An in vitro study [7], using human cadaveric lumbar and thoracic vertebrae, showed that the lavage technique leads to a reduction of cement injection forces compared to the conventional treatment.…”

“…The study, approved by the local animal ethics committee (204/2007), investigated cardiovascular reactions during and after conventional vertebroplasty compared to the newly developed technique using lavage prior to cement injection [15]. In order to verify the in vitro results on reduced injection forces using the lavage technique prior to cement injection [7], the cement injection investigation was incorporated in the mentioned animal study.…”