Multi-center analysis of operative safety of surgery in patients with ALS: The diaphragm pacing experience

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.