Next up on Monday was Michele Basso with When a Good Treatment Fails: Training Type and Molecular Factors in SCI.
I really like this graphic from the presentation. It’s a good summary of all the parts that must be taken into consideration in an SCI. And honestly, I think it could be applied to other diagnoses well too. Take a look, and then I’ll fluff out the details below.
First Michele discussed the injury mechanism circle. She said that in post-mortem dissections of SCIs, the injury often showed upon MRI that the central portion of the cord was where the injury was located, but several neuronal axons survived on the periphery of the injury. This extends several segments along the cord above and below the injury site whether injury is considered complete or incomplete. The inflammation around the injury which is also transmitted throughout the cord also suppresses recovery, and needs to be considered as well. Because of this, the lumbar cord where “CPGs” live in intermediate laminae 7 should be considered as part of the injury. The spinal canal can also absorb inflammation from peripheral injuries.Lovely. Inflammation starts as early as 24 hours after injury.
Now onto the therapists’ specialty: intervention! Keep in mind that task specific intervention such as body weight supported treadmill training (BWSTT) improves functional recovery and strength, but not for everyone. Why? This was the research question being addressed by Hansen et. al. in a series of articles, one of which has been submitted, but is as of yet not published, so this is hot off the press. It seems some people have a genetic mutation that does not allow them to develop the inflammation post-injury: Inflammatory Regulator Matrix Metalloproteinase 9 is what it’s called or MMP9 for short. Early task specific intervention seems to drive better functional recovery in the presence of MMP9 mutation, but without the mutation is harmful by increasing the inflammation around the injury site. The inflammation if leading to maladaptive neuroplasticity, hyper- excitable reflexes, and no motor learning. BUT if we wait for the inflammation to decrease naturally, it is too late for the intervention to work to its full capacity. So we need to address the inflammation, so we can better address the function. How can we do that? Inflammation inhibitors are very expensive, BUT since the cord tends to absorb inflammation from the periphery, they are speculating the opposite may be true as well: if we can get anti-inflammatories to the periphery and allow those to be absorbed too. One interesting method of decreasing inflammation is utilizing eccentric muscle contractions. So Michele suggested using downhill BWSTT instead of flat training early on. I had never even considered changing the pitch of the treadmill! I’m not even sure if the treadmills at my place can do that.
So in summary, type and timing of the intervention you chose DO matter and so does the microenvironment.