ALS Patient Information
How is the diaphragm affected by Amyotrophic Lateral Sclerosis (ALS)?
With ALS, aka your nerves' ability to signal your muscles decreases over time. This also affects your breathing nerves (phrenic nerves), which lose their ability to carry the message from your brain to your diaphragm. Ultimately, ALS / MND weakens your diaphragm. As your diaphragm weakens, you develop breathing problems or respiratory insufficiency. The condition is called chronic hypoventilation, which means you're no longer drawing enough oxygen into your lungs.
Your physician will order one or more of the following tests to determine if you meet the minimum thresholds for treatment and insurance approval:
- Forced Vital Capacity (FVC) < 50% predicted
- Maximum Inspiratory Pressure (MIP) < 60cm H2O (Water)
- Arterial Blood Gas (ABG) > or = 45mm Hg (Mercury)
- Oxygen Saturation (SaO2), 88% for 5 consecutive minutes during sleep
How can the NeuRx Diaphragm Pacing System® help with my breathing problem from ALS?
The NeuRx Diaphragm Pacing System® can help those with Lou Gehrig disease:
- Help you to breathe and live longer
- Condition diaphragm muscle to improve fatigue resistance during normal exertion
- Delay your reliance on a ventilator and its associated inconveniences and lifestyle constraints.
- Improve your quality of your sleep
The state-of-the-art NeuRx DPS® is engineered to be inconspicuous with its compact design and operate silently with no moving parts.
What were the outcomes?
The NeuRx DPS® was evaluated in a clinical study, http://clinicaltrials.gov/ct2/show/NCT00420719 at 9 clinical centers (8 in the U.S. and 1 in France). In the study 86 patients with ALS had breathing problems like those described in the NeuRx DPS® Indications for Use. The risks and benefits of NeuRx DPS® are based on the results of these 86 patients compared to matched patient groups in two other published studies.
The trial identified average probable benefits for patients:
- The patients who used the NeuRx DPS® plus non-invasive ventilation (NIV) (such as BiPAP®) survived 16 months longer (on average) than patients who just used NIV. This 16 month time frame is from the time of diagnosis. Survival time was measured until death or the need for a full time ventilator and a tube in the throat (tracheostomy). The patients who just used NIV were similar patients in a different study.
- The patients who used the NeuRx DPS® plus NIV survived 9 months longer (on average) than patients who just used NIV. This is from the time they started using NIV.
- Some patients could not get used to or were unable to use NIV but used the NeuRx DPS®. They survived an average of 16 months after getting the NeuRx DPS®.
- Some patients had a feeding tube placed with the NeuRx DPS®. All of these patients survived past 30 days. Normally, 2 to 25 patients out of 100 (up to a fourth of all patients) would not survive this long.
- Some patients had their sleep tested just before their NeuRx DPS® implant and again after using the NeuRx DPS® for 4 months. They had better sleep with DPS, with reduced apneas and hypopneas during REM sleep, than before they received NeuRx DPS®. (Gonzalez-Bermejo, et.al., "Diaphragm Pacing Improves Sleep in Patients with Amyotrophic Lateral Sclerosis", accepted for publication in Amyotrophic Lateral Sclerosis Journal, 2011)
What are the Main Tradeoffs and Risks?
In order to obtain the potential benefits of NeuRx Diaphragm Pacing System (DPS)® ALS treatment, you will need to undergo a routine laparoscopic surgical procedure with four short incisions to have the electrodes implanted in your diaphragm (breathing muscle). All surgery involves risks including the risks of anesthesia, respiratory complications and infection. With this procedure, there is a risk of abdominal air getting through the diaphragm and going into the chest cavity during the surgery (capnothorax). Most of the time, the problem goes away on its own but sometimes it requires placement of a small tube in the chest for a short time and extra time in the hospital.
What concerns should I have about the implant surgery?
To obtain the Humanitarian Device Exemption approval from FDA, it was necessary to demonstrate that "the probable benefit to health from the use of the device outweighs the risk of injury or illness, taking into account the probable risks and benefits of currently available devices or alternative forms of treatment". The main risks identified in the trial were the risks associated with the surgery to implant the electrode wires into the diaphragm:
- Problems caused by the abdominal air getting through the diaphragm and going into the chest cavity during the surgery (capnothorax). Two patients (in about 1 out of every 43 patients) needed special treatment to resolve this problem. In another 13 patients (in about 1 out of every 7 patients), the problem occurred but went away on its own.
- Reaction to anesthesia. One patient had a serious reaction to anesthesia. The surgery was then cancelled before any incision was made.
So I can I use BiPAP® (Bilevel Positive Airway Pressure)/ NIV with NeuRx DPS®?
Yes. In the clinical trial of 86 people with ALS and chronic hypoventilation, the NeuRx DPS® demonstrated an ability to enhance the benefit over NIV (e.g., BiPAP®) alone.
This is because NIV and NeuRx DPS® work in different ways. NIV helps rest the accessory breathing muscles while NeuRx DPS® works to maintain diaphragm condition by maintaining diaphragm fatigue resistant muscle fibers.
Can I have a feeding tube (PEG) placed at the same time of surgery?
Yes. Your surgeon may recommend that you receive both the NeuRx DPS® and a feeding tube to supplement your nutrition. In the clinical trial of 86 people with ALS and chronic hypoventilation, a PEG was placed in 24 of the patients at the same time as the DPS implant. There was a remarkable improvement in the survival rate at 30 days, 6 months and 12 months following the PEG and DPS placement, when compared to other published studies of PEG alone.
However, there are still risks associated with PEG placement. One of the 24 patients in the study experienced a fever about one week post implant and it was found that the PEG had moved out of the stomach, causing an abscess. Those problems led to the patient needing breathing support, through a tube in their throat (tracheostomy), from a breathing machine (ventilator).
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