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Objectives: Bilateral diaphragmatic dysfunction results in severe dyspnoea, usually requiring oxygen therapy and nocturnal ventilatory support. Although treatment options are limited, phrenic nerve reconstruction (PR) offers the opportunity to restore functional activity. This study aims to evaluate combination treatment with PR and placement of a diaphragm pacemaker (DP) compared to DP placement alone in patients with bilateral diaphragmatic dysfunction., Methods: Patients with bilateral diaphragmatic dysfunction were prospectively enrolled in the following treatment algorithm: Unilateral PR was performed on the more severely impacted side with bilateral DP implantation. Motor amplitudes, ultrasound measurements of diaphragm thickness, maximal inspiratory pressure, forced expiratory volume, forced vital capacity and subjective patient-reported outcomes were obtained for retrospective analysis following completion of the prospective database., Results: Fourteen male patients with bilateral diaphragmatic dysfunction confirmed on chest fluoroscopy and electrodiagnostic testing were included. All 14 patients required nocturnal ventilator support, and 8/14 (57.1%) were oxygen-dependent. All patients reported subjective improvement, and all 8 oxygen-dependent patients were able to discontinue oxygen therapy following treatment. Improvements in maximal inspiratory pressure, forced vital capacity and forced expiratory volume were 68%, 47% and 53%, respectively. There was an average improvement of 180% in motor amplitude and a 50% increase in muscle thickness. Comparison of motor amplitude changes revealed significantly greater functional recovery on the PR + DP side., Conclusions: PR and simultaneous implantation of a DP may restore functional activity and alleviate symptoms in patients with bilateral diaphragmatic dysfunction. PR plus diaphragm pacing appear to result in greater functional muscle recovery than pacing alone., (© The Author(s) 2021. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.)

Objectives: Phrenic nerve stimulation for diaphragm pacing allows patients with central respiratory paralysis to be weaned from mechanical ventilation. Two procedures are available, either intrathoracic (bilateral thoracotomy) or intradiaphragmatic (four ports laparoscopy). The present experimental work assesses the feasibility, safety and efficacy of a trans-mediastinal implantation of intradiaphragmatic phenic nerve stimulation electrodes using a flexible gastroscope through a cervical incision., Methods: We operated on nine ewes. After selective bronchial intubation, we dissected the latero-tracheal space and opened both mediastinal pleura. We then introduced a flexible gastroscope into the pleural cavities, in a sequential manner. The phrenic nerves were located and followed up to the diaphragm dome. Electrodes loaded within a long, pliable needle were introduced through the adjacent intercostal space and implanted in each hemidiaphragm, at a 'tendinous' location (as close as possible to the entry of the nerve in the central tendon), and at a more lateral 'muscular' location. Postoperatively, the animals were ventilated using bilateral phrenic nerve stimulation. After euthanasia, abdominal verification of the electrodes position was performed through a laparotomy., Results: The mediastinal and pleural parts of the procedure were uneventful. The insertion of electrodes was associated with transdiaphragmatic puncture and small abdominal haematomas in the first two animals studied. After a slight modification of the insertion technique, this was not observed anymore. Phrenic nerve stimulation produced efficient ventilation, with tidal volumes significantly higher when delivered at the tendinous site than at the muscular site., Conclusions: The trans-mediastinal implantation of intradiaphragmatic phrenic nerve stimulation electrodes is feasible, appears reasonably safe, and allows efficient ventilation.

Objective: Diaphragm pacing by phrenic nerve (PN) stimulation is currently used for patients with central respiratory paralysis to be weaned from mechanical ventilation. Electrodes are inserted either through bilateral thoracotomy or through four ports laparoscopy. The aim of this experimental work is to demonstrate the feasibility of trans-mediastinal bilateral implantation of PN electrodes using a flexible gastroscope introduced through a cervical incision in human cadavers., Methods: Ten refrigerated and non-embalmed cadavers were used. The gastroscope was introduced through a cervical incision into the latero-tracheal space and then subsequently into both pleura by opening the mediastinal pleura. After identification of the PN, electrodes were introduced through an intercostal space to the desired diaphragmatic location using a long, pliable needle with the electrode loaded in its lumen., Results: Results are described for each hemi-diaphragm not for an anatomic subject. Mediastinal exploration and introduction of the video gastroscope into the pleural cavities proved easy in all subjects. Pleural adherences were present in five hemi-diaphragms. The central tendon of both hemi-diaphragms could be identified unambiguously in all the subjects. Identification of the entry point of the phrenic nerve into the diaphragm was straightforward in 10 hemi-diaphragms. In the remaining 10, this proved more difficult because of mediastinal fat or lung parenchyma. Introduction of the electrode-holding needles through the intercostal space and their insertion close to the phrenic nerve entry point was also easy. Withdrawal of the needle from the diaphragm and 'capture' of the hook were successful on the first attempt in 14 hemi-diaphragms, but failed in six others in whom a second attempt was necessary., Conclusion: Trans-mediastinal implantation of PN stimulation electrodes is possible using a flexible endoscope. This application of endoscopic surgery could allow a minimally invasive placement of PN electrodes in patients with central respiratory paralysis, for example, at the time of tracheostomy., (Copyright © 2011 European Association for Cardio-Thoracic Surgery. Published by Elsevier B.V. All rights reserved.)

We present the case histories of two children having respiratory failure due to bilateral diaphragm paralysis after cardiac surgery. In both children non-invasive positive pressure ventilation alleviated respiratory distress, improved gas exchange, and prevented the need for endotracheal intubation. Following unilateral recovery of diaphragmatic function both children were successfully weaned from non-invasive positive pressure ventilation.

Over 1200 patients with motor neuron disease have been carefully diagnosed, followed, and included in a detailed database delineating characteristics of the disease. Of these patients, 831 were identified as exhibiting typical, sporadic amyotrophic lateral sclerosis (ALS). The progression of the disease in these patients has been followed with our scoring system, and the ALS score was verified as a significant covariate of survival. Age at first symptom, delay from first symptom to entering ALS clinic, and rate of change of respiratory function were also identified as significant covariates of survival. These measures, applied to the Cox proportional hazards model, were used to develop a mathematical model for prediction of survival time in ALS, which proved highly accurate for the 80% of patients at intermediate risk. For those patients, a second model was developed which accurately predicts, after an initial period of observation, the time over which ALS patients will decline a set number of points in total ALS score. Such validation permits initial trials for drug therapies in ALS by comparison of relatively small groups of treated patients to this historical control group, based on the model of predicted time to a particular decrement in total ALS score.

During an 8-month period, 86 consecutive infants and children under 2 years of age underwent palliative or corrective cardiac surgery, of whom 11 subsequently developed phrenic nerve injury (PNI). This was seen most frequently following classic or modified Blalock-Taussig shunts. The diagnosis was established by ultrasound screening of the diaphragm, and patients were initially managed expectantly with ventilatory support. In nine patients no further management was necessary with demonstrated return of diaphragmatic function. The remaining two patients underwent plication of the diaphragm. The mean time to diaphragmatic recovery was 40.8 days and was more prolonged in patients with paradoxical, as opposed to absent, diaphragmatic movement. There were no deaths in the series. A further retrospective review of 241 patients of similar age undergoing similar surgery over the preceding 2 years revealed evidence of PNI in 11 (4.6%). Recovery of diaphragmatic function was documented in all except one patient who died. Based on these results we believe that although PNI is associated with considerable morbidity, and frequently a long stay in Intensive Care, there is evidence of spontaneous recovery of diaphragmatic function in 90% of the patients. Consequently, plication of the diaphragm can usually be avoided. Ultrasound scanning is extremely useful in establishing the diagnosis and offers assistance in predicting prognosis and deciding management.