How Pigs Can Help Your Back Pain

One of the best human partners in medical research is the humble pig. Pigs seem like an unlikely “equivalent” to test new medical procedures for humans, but they are greatly helpful to determine what will or won’t work in our own bodies. For certain clinical studies, they are ideal laboratory animals. Pigs and humans share many anatomic similarities, such as comparable kidneys and hearts. Another example is skin; when injured, a pig’s skin heals much like ours.

When it comes to testing procedures for human spinal conditions, such as facet joint pain in the lumbar area (lower back), the same spinal region in pigs is a good equivalent.ⁱ

Testing MRI imaging for facet joints

Sheng et al. (2016) conducted a study on how MRI imaging could best be used to confirm accuracy of MRI-guided Focused Ultrasound (MRgFUS) for relieving facet joint pain. Magnetic Resonance Imaging can be programmed for various parameters or pulse sequences that highlight different tissue features. The small facet joints between the backbones (vertebrae) that make up the spine are bony projections lined with cartilage for cushioning and lubrication. In and around the joints are the other soft tissues that make up the back: nerves, muscles, ligaments, tendons, and blood vessels.

The study authors write that there are “challenges regarding MR imaging and temperature mapping due to susceptibility effects between the bone and soft tissue near the joint….” This means that some types of tissues or structures show up more accurately with one MRI pulse sequence than another. Treating facet joint pain with MRI-guided ultrasound beams requires identification of joints and nerves for precision, so using MRI after treatment to verify its success and avoidance of collateral damage requires top quality, high resolution imaging of each type of tissue involved. The study’s goal was to determine which pulse sequences (T1-, T2-, and T2*-weighted and perfusion MRI) were best suited to the task.

6 pigs treated

This is where the pigs come in. Six pigs received MRgFUS to treat facet joints in the lower (lumbar) spine. Before the Focused Ultrasound was delivered, T2-weighted MRI was used to plan treatment. Directly after treatment, all parameters were used to capture images of the treated areas. The authors found that T2-weighted images together with delayed contrast-enhanced T1-weighted sequences produced the most informative scans. All treatments were determined to have been successful.

We thank the pigs for confirming good news about MRI and MRgFUS. The Sperling Medical Group offers MRI-guided Focused Ultrasound (MRgFUS), a noninvasive method for deadening the nerves that carry facet pain messages to the brain. Our MRI is performed on a powerful, state-of-the-art magnet with full pulse sequence capabilities. To find out if MRgFUS is right for you, contact the Sperling Medical Group.

---

ⁱSheng SR, Wang XY, Xu HZ, Zhu GQ, Zhou YF. Anatomy of large animal spines and its comparison to the human spine: a systematic review. Eur Spine J. 2010 Jan;19(1):46-46.
ⁱⁱKrug R, Do L, Rieke V, Wilson MW, Saeed M. Evaluation of MRI protocols for the assessment of lumbar facet joints after MR-guided focused ultrasound treatment. J Ther Ultrasound. 2016 Apr 6;4:14.