Amyotrophic lateral sclerosis (ALS), sometimes referred to as “Lou Gehrig’s Disease“, is a progressive neurodegenerative disease that affects motor nerve cells in the brain and the spinal cord ultimately leading to muscle paralysis.
The diaphragm is a large muscle that moves air across the lungs to facilitate gas exchange and oxygenation of the tissues:
In ALS degeneration of the motor nerve cells that innervate the innervate the diaphragm via the phrenic nerves ultimately leads to respiratory failure.
The diaphragm (purple arrows) a large muscle innervated by the phrenic nerves (green arrows).
The diaphragmatic pacing (DP) system bypasses the degenerated phrenic nerves in ALS, and provides direct electrical stimulation to the diaphragm, facilitating enhanced ventilation.
So we know we can electrically stimulate the weak or paralyzed diaphragm and make it contract.
xx
However, the real question is does this make a difference in terms of life and survival?
We have already blogged about the symptoms of nocturnal hypoventilation and benefits of NIPPV.
Here is a link to a recent summary of studies that have looked at DP for hypoventilation in ALS:
Data presented to the FDA in 2011 included 106 ALS patients who had undergone the surgery.
DP patients lived 9 months longer than a historical cohort of ALS patients with respiratory difficulties treated with NIPPV.
Unlike NIPPV, DP patients do not have to use a mouthpiece or mask.
However, the serious surgical complication rate from the procedure was 3.5%, 26% patients report mild-moderate discomfort from the electrical stimulation, and there were many technical problems including broken electrodes.
In ALS, unlike in spinal cord injury, the denervated diaphragm muscle will ultimately become inexcitable, rendering the DP system ineffective.
DP surgery costs about $20,000, compared to <$1000 for a NIPPV system.
xx
So, the jury is still out.
But before you sign up for DP,
Consider these facts:
DP is FDA approved as a medical device not as a therapy.
Many neuromuscular physicians are calling for real outcome data before widespread adoption of this invasive and expensive interventional procedure. In response to these concerns, the Muscular Dystrophy Association (MDA) and ALS Association (ALSA) have co-sponsored a prospective study to determine whether the DP system in effective or not.
Finally, we know that ALS patient care varies at different centers around the country. However, we don’t know how many ALS patients are getting their FVC measured or being assessed for hypoventilation appropriately. We hope that the new MDA sponsored clinical registry will answer this question.
xx
Find out more:
Click here to find out more about hypoventilation in neuromuscular diseases.
Click here to link to a podcast about DP in ALS.
Click here to find out more about the DP system from the device manufacturer.
Click here to find out more about the DP clinical trial.
Neurology Update 