Traditional spinal surgery is done via long, open incisions in the middle of the back. Once these incisions are made the skin and muscles are held out of the way using large, sharp metal retractors (see image 1).
Image 1: Large metal retractors used in traditional spinal surgery. (courtesy of Deukmedjian et al, http://www.practicalpainmanagement.com, July 2012.)
Multiple studies have shown real, long-lasting muscle injury when these retractors are used for prolonged periods of time. That’s right, these retractors have actually been shown to destroy surrounding muscle if they’re in place long enough. Look at image 2: the image on the left is a normal MRI of the lumbar spine. The red arrow points to the normal paraspinal muscles that run along your spine. The image on the right demonstrates what can happen after a long traditional spinal surgery: the muscle has died and has been replaced with fat (red arrow.)
Image 2: Normal MRI of lumbar spine, left; MRI showing paraspinal muscle injury, right.
Why is this so bad? These paraspinal muscles act much like the cables of a suspension bridge: they provide critical support to the spine, especially with movement. If the muscles are injured this can have serious long-term consequences to the structural stability of the spine (more on this in the next post.)
Image 3: A tubular retractor in place over the lumbar spine.
Minimally-invasive techniques in spinal surgery often use small tubular retractors (see image 3 and video below) to gently spread the muscles out the way so that they are not injured during surgery. By avoiding muscle injury, minimally-invasive techniques lead to the benefits we’ve already discussed (decreased pain, decreased blood loss, shorter hospital stays, etc.) AND may also prevent future spinal problems after surgery.