Surgical Induction of Lumbar Spine Instability in Mouse Model: A Surgical Procedure for the Resection of the Lumbar Spinous Processes and Connected Ligaments in Murine Model

To begin, prep an anesthetized mouse in the prone position. Position a customized surgical pad under its abdomen to raise the lumbar spine and facilitate access to the site. Next, identify the lumbar spine via the outward pointing subcutaneous spinous processes or bony projections off the posterior of each vertebrae.

Make a midline skin incision from the mid-thoracic to the lumbar region to expose the underlying fascia or connective tissue layer. Locate the third lumbar spine vertebra or L3, present in the middle of the lumbar spine, by its wedge-shaped spinous process. Further, identify the L4 and L5, respectively. Separate the posterior paravertebral muscles from the L3–L5 vertebrae to expose their spinous processes and ligaments.

The ligaments of the spinous processes consist of interspinous ligaments - thin, membranous bands interconnecting the spinous processes of neighboring vertebrae and supraspinous ligaments -  dense, fibrous cords linking together the apices of spinous processes of the adjacent vertebrae. Together, these ligaments stabilize the vertebral column.

Now, remove the interspinous ligaments from the L3-L5 vertebrae to separate the individual spinous processes. Resect the L3-L5 spinous processes along with their supraspinous ligaments. Close the surgical incision without reattaching the paravertebral muscles. Return the mouse to its cage. The resection of the whole L3-L5 spinous processes with ligaments and detachment of paravertebral muscles cause lumbar spine instability in the mouse.