Preoperative parameters and their prognostic value in amyotrophic lateral sclerosis patients undergoing implantation of a diaphragm pacing stimulation system.

INTRODUCTION: Amyotrophic lateral sclerosis (ALS) is a progressive neuromuscular disease with devastating and fatal respiratory complications. Diaphragm pacing stimulation (DPS) is a treatment option in diaphragm insufficient ALS patients. Ventilatory insufficiency depending on diaphragmatic failure is treated by the present study aimed to investigate prognostic value of preoperative clinical and functional characteristics of ALS patients undergoing implantation of a DPS system and to determine appropriate indications for the DPS system. METHODS: The study included 34 ALS patients implanted with DPS system. All patients underwent multidisciplinary and laboratory evaluations before the surgery. The laboratory examinations included pulmonary function tests and arterial blood gas analysis. Survival rates were recorded in a 2-year follow-up after the surgery. RESULTS: Twenty-eight of 34 patients with ALS survived after a 2-year follow-up. These patients were younger than those who died and had the disease for a longer time; however, the differences were not significant. Both right and left hemidiaghragms were thicker in the survived patients (P < 0.0001 for each). Pulmonary function tests revealed no significant differences between the patients who survived. Arterial blood gas analysis demonstrated lower partial pressure of carbon dioxide in the survived patients (P = 0.025). CONCLUSIONS: DPS implantation was more efficacious in ALS patients with mild respiratory failure and thicker diaphragm. Predictors of long-term effectiveness of DPS system are needed to be addressed by large-scale studies.

Importance of diaphragm thickness in amyotrophic lateral sclerosis patients with diaphragm pacing system implantation.

INTRODUCTION: Severe respiratory failure develops as a result of the involvement of the respiratory muscles in patients with amyotrophic lateral sclerosis (ALS). Implantation of diaphragm pacing system (DPS) has been carried out on ALS patients since 2005 to avoid these situations, but the importance of diaphragm thickness has not yet been established clearly. MATERIAL AND METHOD: We retrospectively evaluated 34 ALS patients who had previously implanted DPS to detect the importance of diaphragm thickness. We investigated the effect of diaphragm thickness, which was measured by preoperative thorax computerized tomography on preoperative respiratory function tests (RFT), arterial blood gas (ABG) analysis, postoperative 3- and 6-month oxygen saturations and mortality. RESULTS: The right diaphragm thickness was calculated as 4.60 (2.95-6.00) mm, while the left diaphragm thickness was 4.10 (2.77-6.00) mm. Six patients died during the follow-up period. We did not detect a significant relationship between ABG parameters, RFT and diaphragm thickness. However, according to our observations, the diaphragm thickness was significantly related to mortality. The right diaphragm was significantly thinner in cases that required preoperative respiratory support and had percutaneous endoscopic gastrostomy. When the cut-off values for the diaphragm thickness were accepted as 3.50 mm, significantly higher mortality among patients below this was observed. CONCLUSION: Diaphragm thickness is an important criterion in cases for which DPS implantation is planned. We consider that avoidance of DPS implantation is more suitable for cases with a diaphragm thickness below 3.50 mm because of mortality.