Performing Thoracic Spinal Cord Hemisection Surgery in Rats

Secure an anesthetized rat with a shaved dorsal trunk in a stereotaxic frame.

Disinfect the shaved area and cover the rat with a drape.

Make an incision and retract the skin and subcutaneous fat over the thoracic T6 to T10 vertebrae.

Separate the paravertebral muscles to expose the T7 to T9 vertebrae.

Bilaterally cut the facet joints on the T7 and T8 vertebrae.

Superficially cut the dorsal connective tissue between the T8 and T9 vertebrae.

Remove the T8 spinous process and slightly rotate its lamina.

Cut the lamina on both sides, exposing the spinal cord.

Apply anesthetic and remove the dura covering the T8 spinal segment.

Identify the spinal cord midline and cut toward one side, without damaging the anterior spinal artery.

This hemisection disrupts the neural tracts on one side.

Place a saline-soaked absorbent sponge to control bleeding.

Suture the incision and allow the rat to recover.

After confirming a lack of response to toe pinch in an anesthetized adult rat, make a 2.5-centimeter incision in the shaved skin overlying the T6 to T10 vertebrae, and use blunt scissors to retract the skin and superficial fat. Use blunt dissection scissors and a self-retaining retractor to separate the paravertebral muscles, inserting on the dorsal aspect of the T7 to T9 vertebrae, and use fine forceps and cotton-tipped applicators to debride and clear any remaining tissue to expose the spinous processes and vertebral lamina.

Place the rat under a stereomicroscope, and use delicate bone trimmers to carefully cut the facets bilaterally on the T7 and T8 vertebrae. Use a scalpel to make a 1 millimeter superficial cut in the dorsal connective tissue between the T8 and T9 vertebral laminae, taking care not to injure the underlying cord, and use bone trimmers to remove the spinous process of the T8 vertebra.

With curved hemostatic forceps, carefully clamped on the T7 spinous process, rotate the caudal end of the T8 laminae slightly rostrally approximately 20 degrees, and insert the bone trimmers under the T8 lamina. Make a midline cut extending along the lamina, continuing the laminectomy by repeating the cuts on the left and right side of the vertebral lamina, medial to the transverse processes to expose the spinal cord.

Drip 100 microliters of 2% lidocaine into the exposed spinal canal, and use fine forceps and iridectomy scissors to remove the dura, overlaying the T8 spinal segment. Repeat the lidocaine administration to the exposed cord and identified the midline of the cord by visualization of a center line created between the spinous processes extending between the exposed T7 to T9 vertebra.

Using fine forceps to stabilize the spinal cord, use a dissecting knife to hemisect the spinal cord from the midline toward one side of the animal, taking care not to cut through the anterior spinal artery on the ventral side. Using iridectomy scissors, carefully cut through any remaining tissue on the lesion side of the spinal cord to ensure the ventrolateral quadrant is appropriately transected, and place a sterile, approximately 6 by 2-millimeter saline soaked hemostatic sponge into the exposed cavity above the spinal cord.

Then use 4-0 polyglactin 910 sutures to close muscle layers and the skin around the incision site and place the rat in a warm environment under a heat lamp with monitoring until full recovery.