Lumbar neuroforaminal decompression using a flexible micro blade shaver system - results of a cadaveric study

BACKGROUND: The lumbar neural foraminal stenosis still is a challenging condition in minimally invasive spine surgery. Due to the anatomic situation a complete decompression of the nerve root often leads to a sub total facetectomy associated with potential instability and the need for additional instrumentation of the decompressed segment. The iO-Flex system was introduced to address this problem by using a minimally-invasive wire-guided microblade shaver to increase the neuroforaminal space by reducing the stenosis from intraforaminal while sparing bigger parts of the facet joint. In this study we evaluated the feasibility and the surgical and radiological success in relation to the experience of the surgeon.

METHOD: We performed decompression of the neuro foramen in ten lumbar levels of two fresh frozen human cadavers. Before and after decompression, we obtained high-resolution computerized tomography (CT) data to evaluate the diameter of the neural foramen.

RESULTS: The mean foraminal width (7.88mm to 10.94mm, p<0.0001) and area (123.27mm(2) to 149.18mm(2), p<0.003) increased significantly after the decompression, while the facet joints area (131.9mm(2) to 107.51 p<0.005) and width (16.4mm to 13.75mm, p<0.001) indeed decreased significantly but with an overall reduction of facet joint width by 16% and facet joint area by 18%. No complications such as nerve root damages or dural tears were observed.

CONCLUSION: The flexible micro blade shaver system is feasible with a steep learning curve and achieves sufficient decompression of the neuroforamen in this cadaveric study.