Biomechanical Analysis of Inspan Spinous Process Fixation Alone in The Lumbar Spine Demonstrates Positive Results

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Biomechanical studies of the Inspan device suggest it may be the strongest interspinous fixation device on the market and thus is being used for spinal fusion replacing the traditional method that uses pedicle screws and interbodies with laminectomies.

Inspan ScrewLES Fusion

INSPAN LLC (a privately-owned company) is pleased to announce the positive results from a biomechanical analysis of spinous process fixation alone or with facet screws in the lumbar spine using the Inspan interspinous fixation device (INSPAN LLC). Unlike extension block design, the Inspan device fixates the spine to allow for immediate stability, distraction, decompression, and fusion. Biomechanical assessments of interspinous process fixation have demonstrated particularly advantageous outcomes in stabilizing the sagittal plane for during flexion and extension. Biomechanical studies of the Inspan device suggest it may be the strongest interspinous fixation device on the market and thus is being used for spinal fusion replacing the traditional method that uses pedicle screws and interbodies with laminectomies.

The study was performed at the LESS Institute by Professor Dr. Kingsley R Chin, MD, a board-certified orthopedic spine surgeon and coauthors Dr. Fabio Pencle and Dr. Jason Seale.

Human cadaveric spines were biomechanically tested under the following conditions: 1) intact/control; 2) Inspan only, 3) Inspan with facet screws (FS), 4) Inspan with lateral interbody fixation (LIF), 5) Inspan with LIF and FS. Each test consisted of 100 N of axial preload with ± 7.5 Nm of torque in flexion/extension (FE), right/left lateral bending (LB), and right/left axial rotation (AR).

The study showed a decrease in flexion-extension, lateral bending and axial bending in all conditions compared to intact control. Adding facet screws does not improve stability during flexion/extension (already best loading mode for spine process plating). With LIF, each point of fixation added (FS or Inspan) incrementally improves stability by about the same amount during lateral bending and axial rotation.

In conclusion, Inspan proved effective biomechanically in increasing foraminal height and restricting flexion/extension motion. Other effects without LIF, Inspan is moderately effective in restricting axial rotation or lateral bending. With the LIF interbody, testing showed better stability than no LIF. The addition of Inspan to lumbar fixation increases foraminal height by 1mm minimum.

About INSPAN, LLC
INSPAN, LLC is privately owned by KICVentures and is focused on advancing the platform of patented interspinous fixation technology. The Inspan device has a proven ten-year track record with thousands implanted since FDA-clearance in 2010.

Inspan FDA Indications
The Inspan Slim Spinous Process Plate System is a posterior non-pedicle supplemental fixation system intended for use in the non-cervical spine (T1-S1). It is intended for plate fixation/attachment to the spinous process for the purpose of achieving supplemental fusion for the following indications: spondylolisthesis, trauma (fracture ordislocation), tumor, or degenerative disc disease (defined as discogenic pain with degeneration of the disc confirmed by history and radiographic studies). The device is intended for use with bone graft material and is not intended for stand-alone use.

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