Raymond Onders, MD1, Arthur Carlin2, Brian Dunkin3, Gregg Jossart4, Michael Marohn5, Fabrice Menegaux6, John Morton7, C Daniel Smith8. 1University Hospitals Case Medical Center, 2Henry Ford health System, 3Methodist Hospital, 4California Pacific Medical Center, 5John Hopkins, 6Pitie Hospital, 7Stanford School of Medicine, 8Mayo Clinic
INTRODUCTION: With the growing prevalence of patients with amyotrophic lateral sclerosis(ALS) there is a need to describe and analyze the correct peri-operative management. ALS is a progressive neurodegenerative disease that has devastating effects to respiratory muscles resulting in respiratory failure death in 80% of patients. Diaphragm pacing (DP) replaces ventilators in spinal cord injury patients and delays death and tracheostomy in ALS patients. This report outlines the peri-operative outcomes to 90 days for patients in a multi-center pivotal FDA trial of DP in ALS.
METHODS: The study was conducted under an investigational device exemption (IDE G040142, clinicaltrials.gov NCT00420719) from the U.S. FDA and IRB approval. Patients underwent three pre-operative neurophysiologic assessments to quantify diaphragm function. Inclusion criteria included chronic hypoventilation with intact diaphragm motor units to stimulate. A standardized ALS functional rating scale (ALSFSR-R) was completed serially pre and post-operatively. Patients underwent general anesthesia with no paralytics with laparoscopic implantation of the diaphragm pacing electrodes in each hemi-diaphragm. Post-operative ALSFSR-R results and complications were noted. Data were analyzed with Stata 13.0.
RESULTS: At eight worldwide sites, 107 patients went to surgery with 106 patients successfully being implanted with DP. One patient had a reaction to anesthesia requiring cancellation of surgery. Twenty-eight patients received a simultaneous percutaneous gastrostomy tube (PEG).  There were 73 males and 36 females with a median age of 57.9 years (range 32 to 76). The mean lead-in time was 2.7 ± 0.6 months from consent to implant. The mean post-op period was 3.8 ± 1.0 months from implant to data collection. There were no deaths within 30 days post implant. Three in the non-PEG group, died within 90 days. The median ALSFRS-R score at implant was 28 points(on the 48 point scale). The lead-in period rate of decline was compared on a paired, patient-by-patient, basis to the rate of decline for the post-operative treatment period. There was no significant change in the rate of decline of this functional scale(lead-in slope -0.80 vs post-op slope -0.73 with p value =0.50). There were 4 serious adverse effects: 2 capnothorax, 1 respiratory failure following complications from surgery(dislodgement of gastrostomy); and 1 post-operative chest pain.
CONCLUSION: There was no degradation in function for ALS patients undergoing surgical procedures when no paralytics are used and DP is placed. The diagnosis of ALS should not prevent a patient from being considered for a surgical procedure when necessary and to improve their quality of life.