Dec. 22, 2008

Surgeon Reports on ALS Diaphragm Pacing

Raymond Onders, director of Minimally Invasive Surgery at University Hospitals Case Medical Center in Cleveland, presented data at the 19th International Symposium on ALS on 88 patients who were involved in trials of an implanted diaphragm pacing system. The Symposium was held in Birmingham, United Kingdom, Nov. 3-5. (For additional news from this meeting, see International Symposium.)

A diaphragm pacing system uses surgically implanted electrodes in the diaphragm, a major respiratory muscle located under the ribcage, to cause regular, rhythmic muscle contractions. It works similarly to a cardiac pacemaker, which regulates the heartbeat.

The goal of diaphragm pacing, which can be used in combination with noninvasive positive pressure ventilation, is to help maintain respiratory function artificially while preserving as many remaining muscle fibers in the diaphragm as possible.

Onders presented results from a pilot study of 16 ALS patients who received pacing systems and a second, larger study of 72 who got the devices.

In the long-term follow-up of the pilot study, patients with declining respiratory capacity during the lead-in period showed a slower rate of decline after receiving the implanted pacing system, said Onders, who holds Margaret and Walter Remen Chair in Surgical Innovation at Case. He also said the respiratory items on the ALS Functional Rating Scale did not decline despite deteriorating scores overall.

In summarizing results from all trial participants who received diaphragm pacing systems, Onders noted that some have had the device for as long as two years and that so far no one has been unable to tolerate it. All 26 patients who received a pacing system and also had a gastrostomy (feeding) tube were alive 30 days after pacer insertion, and 83 percent were alive after a year.

Onders said he believes diaphragm pacing systems can be safely implanted and utilized in ALS patients and have a positive effect on diaphragm function.

Hans Katzberg in the Department of Neurology & Neurological Sciences at Stanford (Calif.) University has an MDA grant to study the effect of diaphragm pacing on sleep quality in people with ALS.