Diaphragmatic pacing for respiratory failure in children.

Diaphragm pacing is a ventilation strategy in respiratory failure. Most of the literature on pacing involves adults with common indications being spinal cord injury and amyotrophic lateral sclerosis (ALS). Previous reports in pediatric patients consist of case reports or small series; most describe direct phrenic nerve stimulation for central hypoventilation syndrome. This differs from adult reports that focus most commonly on spinal cord injuries and the rehabilitative nature of diaphragm pacing. This review describes the current state of diaphragm pacing in pediatric patients. Indications, current available technologies, surgical techniques, advantages, and pitfalls/problems are discussed.

Successful termination of persistent hiccups via combined ultrasound and nerve stimulator-guided singular phrenic nerve block: a case report and literature review.

Persistent hiccups that occur after abdominal surgery seriously affect postoperative rehabilitation. Phrenic nerve block therapy has been recommended after failure of medication or physical maneuvers. However, the phrenic nerve is often difficult to accurately identify because of its small diameter and anatomic variations. We combined ultrasound with the use of a nerve stimulator to quickly and accurately identify and block the phrenic nerve in a patient with postoperative persistent hiccups. The ongoing hiccups were immediately terminated with no adverse effects. The patient reported no recurrence during the 2-week follow-up period. We conclude that the combined use of real-time ultrasound guidance and a nerve stimulator for singular phrenic nerve block might be an effective intervention for terminating postoperative persistent hiccups, although further studies are needed to evaluate the safety and efficacy of this technique. The findings in this case suggest a potential clinical application for this technique in managing persistent hiccups, thereby contributing to improved patient care and outcomes.

Lateral Displacement of the Phrenic Nerve in C5 Tumors.

BACKGROUND AND OBJECTIVES: Nerve sheath tumors of the brachial plexus frequently distort the local anatomy, increasing the difficulty of safe exposure and resection. However, lateral displacement of the phrenic nerve has not been previously described. The purpose of this study was thus to illustrate the abnormal lateral displacement of the phrenic nerve in 2 cases of patients undergoing brachial plexus tumor resection and provide a possible mechanism for this observation. METHODS: Two patients underwent surgical resection of clinically progressing C5 schwannomas. During exposure, the phrenic nerve was found to be significantly more superficial and lateral than typical. This structural relationship persisted even after complete resection of the lesion. Both patients did well postoperatively. RESULTS: The phrenic nerve traverses along the anterolateral aspect of the anterior scalene. However, in these 2 cases of C5 nerve sheath tumors, the phrenic was found to be significantly more lateral and superficial than usual, draping across the medial aspect of the tumor. We believe that the C5-phrenic communicating branch may act as a functional tether that mobilizes the phrenic nerve laterally as the tumor grows. The mass effect on the anterior scalene by the underlying C5 tumor may further contribute to the anterolateral and superficial displacement of the nerve. CONCLUSION: The phrenic nerve may be seen markedly more laterally and superficially displaced in cases of C5 nerve sheath tumors. It is important for surgeons who operate on lesions of the brachial plexus to be aware of this phenomenon.

Phrenic nerve block combined with stellate ganglion block for postoperative intractable hiccups: a case report.

Postoperative intractable hiccups slow patient recovery and generate multiple adverse effects, highlighting the importance of investigating the pathogenesis and terminating the hiccups in a timely manner. At present, medical and physical therapies account for the main treatments. We encountered a case in which postoperative intractable hiccups after biliary T-tube drainage removal ceased with the application of an ultrasound-guided block of the unilateral phrenic nerve and stellate ganglion. No complications developed, and the therapeutic effect was remarkable. To our knowledge, this approach has not been reported to date. Simultaneously blocking the phrenic nerve and stellate ganglion may be a treatment option for intractable hiccups.

Bilateral selective laryngeal reinnervation in patients with bilateral vocal cord palsy.

Objective: Bilateral selective reinnervation of the larynx aims to restore both vocal cord tone and abductor movements in patients with bilateral vocal cord palsy. Methods: Four females and one male treated by bilateral selective reinnervation of the larynx were included in the present study. In all cases, both posterior cricoarytenoid muscles were reinnervated using the C3 right phrenic nerve root through the great auricular nerve graft, while adductor muscle tone was bilaterally restored using the thyrohyoid branches of the hypoglossal nerve through transverse cervical nerve grafts. Results: After a minimum follow-up of 48 months, all patients were successfully tracheostomy free and had recovered normal swallowing. At laryngoscopy, the first patient recovered a left unilateral partial abductor movement, the second had complete bilateral abductor movements, the third did not show improvements of abductor movements, but symptomatology was improved, the fourth recovered partial bilateral abductor movements and the fifth case did not show improvements and needed posterior cordotomy. Conclusions: Bilateral selective laryngeal reinnervation, although a complex surgical procedure, offers a more physiologic recovery in the treatment of bilateral vocal fold paralysis. Selection criteria still needs to be precisely defined to avoid unexpected failures.

Phrenic Nerve as an Alternative Donor for Nerve Transfer to Restore Shoulder Abduction in Severe Multiple Root Injuries of the Adult Brachial Plexus.

PURPOSE: Nerve transfer is the gold standard to restore shoulder abduction in acute brachial plexus injuries. The aim of this study was to compare the phrenic nerve (Ph) to the spinal accessory nerve (XI) as the donor nerve for this purpose. METHODS: A retrospective chart review was performed on 136 patients with acute brachial plexus injuries who received a nerve transfer of the shoulder with either the Ph (94 patients) or XI (42 patients). Each group was divided into 3 subgroups based on the recipient nerve. The maximum degree of shoulder abduction was recorded after 2 years of postoperative follow-up. A generalized estimating equation model was performed to examine the variables affecting shoulder abduction over time. RESULTS: The maximum degrees of shoulder abduction achieved were 61.9° ± 38.7° in patients with Ph and 51.1° ± 37.3° in patients with XI. More than M3 shoulder abduction was achieved by 67% of patients with Ph versus 59% of patients with XI. The regression analysis showed that the age at the time of surgery correlated more with the functional outcome over time than the choice of donor nerve. CONCLUSIONS: In multiple root brachial plexus injuries, the Ph exhibited similar outcomes to the XI for shoulder abduction. Our routine exploration of the supraclavicular plexus exposes the Ph conveniently for nerve transfer. The phrenic nerve should be considered as an alternative when the XI is not available or is reserved for secondary reconstruction. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

Heart-Lung Transplantation: Technical Modifications to Simplify the Procedure.

Heart-lung transplantation is a mature therapy but has perioperative complications, such as phrenic nerve dysfunction and mediastinal bleeding. We report our technical modifications to simplify the procedure.

Staged Phrenic Nerve Elongation and Free Functional Gracilis Muscle Transplantation-A Possible Option for Late Reconstruction in Chronic Brachial Plexus Injury.

PURPOSE: In patients with late brachial plexus birth injuries, sequelae after acute flaccid myelitis, or chronic adult brachial plexus injury, donor nerves for functioning muscle transplantation are often scarce. We present the results of a potential strategy using the phrenic nerve with staged free gracilis transplantation for upper extremity reanimation in these scenarios. METHODS: A retrospective review was performed on an institutional database of brachial plexus injury or patients with palsy. All patients underwent a staged reconstruction in which the ipsilateral phrenic nerve was extended by an autogenous nerve graft (PhNG), followed by free-functioning gracilis transplantation (PhNG-gracilis). RESULTS: Nine patients (6 cases of late brachial plexus birth injuries, 2 of acute flaccid myelitis, and 1 of adult chronic brachial plexus injury) were included in this study. The median follow-up period following the PhNG-gracilis procedure was 27 months (range, 12-72 months). The goals of the staged PhNG and PhNG-gracilis were primarily finger extension or finger flexion. In some patients, the technique was used to improve both elbow and finger function, tunneling the muscle through the flexor compartment of the upper arm and under the mobile wad at the elbow. All patients exhibited improvement of muscle strength, including in finger extension (4 patients) from M0 to M2; finger flexion (3 patients) from M0 to M3; elbow extension (1 patient) from M0 to M2; and elbow flexion (1 patient) from M2 to M4. CONCLUSIONS: A 2-stage PhNG-gracilis may restore or enhance the residual elbow and/or finger paralysis in chronic brachial plexus injuries. A minimum follow-up period of 3 years is recommended. This technique may remain useful as one of the last reconstructive options to increase power in patients with scarce donor nerves. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic V.

[Relevant anatomy of epicardial space for the electrophysiologists]. / Relevante Anatomie des epikardialen Raums für Elektrophysiologen.

The arrhythmogenic substrate in patients with Chagas cardiomyopathy, arrhythmogenic dysplasia, postmyocarditis nonischemic dilative cardiomyopathy as well as after extensive posterior or anterior wall myocardial infarction is predominantly located epicardially. This can necessitate epicardial access for an effective, substrate-based catheter ablation of the ventricular tachycardia (VT). Anterior percutaneous epicardial puncture represents the standard approach for epicardial VT ablation. The most important anatomical particularities that must be taken into account when performing an epicardial puncture or epicardial VT ablation are epicardial coronary arteries, left phrenic nerve and epicardial fat. The typical anatomic characteristics of the epicardial structures and resulting considerations for epicardial access are discussed here in detail.

[Pulsed field ablation : The ablation technique of the future?] / "Pulsed field ablation" : Die Ablationstechnik der Zukunft?

The ablation of cardiac arrhythmias is now standard therapy in invasive electrophysiology with a focus on atrial fibrillation due to its high prevalence. Thermal energy sources such as radiofrequency or cryoablation are the most commonly used techniques to date. Due to limitations in terms of effectiveness and safety because of possible indiscriminate tissue destruction, ablation using pulsed field ablation (PFA) can be a safe and effective alternative to thermal ablation techniques. This is a nonthermal form of energy that creates effective myocardial lesions by means of irreversible electroporation by generating short, high-energy electrical impulses. Preliminary data show high effectiveness with a low complication rate. Myocardial tissue shows a high specificity while sparing surrounding structures such as the esophagus, the phrenic nerve and surrounding vascular structures. Therefore, irreversible electroporation is a very promising technique and has the potential to become the perfect form of energy for many catheter ablations and especially for pulmonary vein isolation. In this article we provide an overview of the current status of PFA as well as an outlook on future fields of treatment.

Phrenic nerve injury after the percutaneous microwave ablation of lung tumors: A single-center analysis.

Objective: This study aimed to analyze the cases of phrenic nerve injury caused by the percutaneous microwave ablation of lung tumors conducted at our center and to explore the risk factors. Materials and Methods: The data of 455 patients who underwent the percutaneous microwave ablation of lung tumors at the Department of Interventional Radiology, First Affiliated Hospital of Fujian Medical University from July 2017 to October 2021, were retrospectively analyzed. The cases of phrenic nerve injury after the percutaneous ablation were reported to analyze the risk factors involved, such as the shortest distance between tumor margin and phrenic nerve, tumor size, and ablation energy. The groups were divided based on the shortest distance between the tumor edge and the phrenic nerve into group 1, d ≤ l cm; group 2, 1 < d ≤2 cm; and group 3, d >2 cm. Lesions with a distance ≤2 cm were compared in terms of tumor size and ablation energy. Results: Among the 455 patients included in this study, 348 had primary lung cancer, and 107 had oligometastatic cancer. A total of 579 lesions were detected, with maximum diameter of 1.27 ± 0.55 cm, and the ablation energy was 9,000 (4,800-72,000) J. Six patients developed phrenic nerve injury, with an incidence of 1.32%. For these six patients, the shortest distance from the lesion edge to the phrenic nerve was 0.75 ± 0.48 cm, and the ablation energy was 10,500 (8,400-34,650) J. There were statistically significant differences in phrenic nerve injury among groups 1, 2, and 3 (P < 0.05). In patients with a distance (d) ≤ 2 cm, there were no significant differences in tumor diameter and energy between the phrenic nerve injury group and the non-injury group (P = 0.80; P = 0.41). In five out of six patients, the diaphragm level completely recovered to the pre-procedure state, and the recovery time of the phrenic nerve was 9.60 ± 5.60 months. Another one was re-examined 11 months after the procedure, and the level of the diaphragm on the affected side had partially recovered. Conclusions: Phrenic nerve injury is a rare but not negligible complication of thermal ablation and is more likely to occur in lesions with a distance ≤2 cm from the phrenic nerve.

Acellular nerve graft enriched with mesenchymal stem cells in the transfer of the phrenic nerve to the musculocutaneous nerve in a C5-C6 brachial plexus avulsion in a rat model.

INTRODUCTION: Phrenic nerve transfer has been shown to achieve good nerve regeneration in brachial plexus avulsion. Acellular nerve allografts (ANAs) showed inferior results to autografts, which is why its use with mesenchymal stem cells (MSCs) is currently being studied. The aim is to study the effect of BM-MSCs associated with ANAs in a rat model of phrenic nerve transfer to the musculocutaneous nerve in a C5-C6 avulsion. MATERIAL AND METHODS: 42 Wistar-Lewis rats underwent a C5-C6 lesion in the right forelimb by excising a 3 mm segment from both roots, followed by a phrenic nerve transfer to the musculocutaneous nerve associated with the interposition of a three types of nerve graft (randomly distributed): control (autograft) group (n = 12), ANAs group (n = 12), and ANAs + BM-MSCs group (n = 18) After 12 weeks, amplitude and latency of the NAP and the compound motor action potential (CMAP) were measured. Biceps muscles were studied by histological analysis and nerve grafts by electron microscopy and fluorescence analysis. RESULTS: Statistically significant reductions were found in latency of the CMAP between groups control (2.48 ± 0.47 ms) and experimental (ANAs: 4.38 ± 0.78 ms, ANAs + BM-MSCs: 4.08 ± 0.85 ms) and increases in the amplitude of the CMAP between groups control (0.04388 ± 0.02 V) and ANAs + BM-MSCs (0.02275 ± 0.02 V), as well as in the thickness of the myelin sheath between groups control (0.81 ± 0.07 µm) and experimental (ANAs: 0.72 ± 0.08 µm, ANAs + BM-MSCs: 0.72 ± 0.07 µm) and in the area of the myelin sheath between groups control (13.09 ± 2.67 µm2 ) and ANAs (10.01 ± 2.97 µm2 ) (p < .05). No statistically significant differences have been found between groups ANAs and ANAs + BM-MSCs. CONCLUSIONS: This study presents a model for the study of lesions of the upper trunk and validates the autologous graft as the gold standard.

Thoracoscopic Radial Diaphragm Plication.

In appropriately selected patients diaphragm plication improves quality of life by alleviating dyspnea and allowing patients to return to their routine activities. Many plication techniques exist, but the optimal surgical approach remains unclear. We report our experience with a minimally invasive radial diaphragm plication technique. It offers 2 distinct advantages: (1) suture placement avoids the phrenic nerve fibers, allowing for potential nerve recovery, and (2) the interrupted radial sutures improve the distribution of tension along the flaccid muscle and may achieve a more durable repair.

Phrenic Nerve Reconstruction for Effective Surgical Treatment of Diaphragmatic Paralysis.

ABSTRACT: Diaphragmatic paralysis due to phrenic nerve injury may cause orthopnea, exertional dyspnea, and sleep-disordered breathing. Phrenic nerve reconstruction may relieve symptoms and improve respiratory function. A retrospective review of 400 consecutive patients undergoing phrenic nerve reconstruction for diaphragmatic paralysis at 2 tertiary treatment centers was performed between 2007 and 2019. Symptomatic patients were identified, and the diagnosis was confirmed on radiographic evaluations. Assessment parameters included pulmonary spirometry (forced expiratory volume in 1 second and FVC), maximal inspiratory pressure, compound muscle action potentials, diaphragm thickness, chest fluoroscopy, and Short Form 36 Health Survey Questionnaire (SF-36) survey. There were 81 females and 319 males with an average age of 54 years (range, 19-79 years). The mean duration from diagnosis to surgery was 29 months (range, 1-320 months). The most common etiologies were acute or chronic injury (29%), interscalene nerve block (17%), and cardiothoracic surgery (15%). The mean improvements in forced expiratory volume in 1 second and FVC at 1 year were 10% (P < 0.01) and 8% (P < 0.05), respectively. At 2-year follow-up, the corresponding values were 22% (P < 0.05) and 18% (P < 0.05), respectively. Improvement on chest fluoroscopy was demonstrated in 63% and 71% of patients at 1 and 2-year follow-up, respectively. There was a 20% (P < 0.01) improvement in maximal inspiratory pressure, and compound muscle action potentials increased by 82% (P < 0.001). Diaphragm thickness demonstrated a 27% (P < 0.01) increase, and SF-36 revealed a 59% (P < 0.001) improvement in physical functioning. Symptomatic diaphragmatic paralysis should be considered for surgical treatment. Phrenic nerve reconstruction can achieve symptomatic relief and improve respiratory function. Increasing spirometry and improvements on Sniff from 1 to 2 years support incremental recovery with longer follow-up.

Phrenic nerve block during nonintubated video-assisted thoracoscopic surgery: a single-centre, double-blind, randomized controlled trial.

There has been interest in the use of nonintubated techniques for video-assisted thoracoscopic surgery (VATS) in both awake and sedated patients. The authors' centre developed a nonintubated technique with spontaneous ventilation for use in a patient under general anaesthesia using a phrenic nerve block. This treatment was compared with a case-matched control group. The authors believe that this technique is beneficial for optimizing anaesthesia for patients undergoing VATS. The patients were randomly allocated (1:1) to the phrenic nerve block (PNB) group and the control group. Both groups of patients received a laryngeal mask airway (LMA) that was inserted after anaesthetic induction, which permitted spontaneous ventilation and local anaesthesia in the forms of a paravertebral nerve block, a PNB and a vagal nerve block. However, the patients in the PNB group underwent procedures with 2% lidocaine, whereas saline was used in the control group. The primary outcome included the propofol doses. Secondary outcomes included the number of propofol boluses, systolic blood pressure (SBP), pH values of arterial blood gas and lactate (LAC), length of LMA pulled out, length of hospital stay (length of time from the operation to the time of discharge) and complications after 1 month. Intraoperatively, there were increases in lactate (F = 12.31, P = 0.001) in the PNB group. There was less propofol (49.20 ± 8.73 vs. 57.20 ± 4.12, P = 0.000), fewer propofol boluses (P = 0.002), a lower pH of arterial blood gas (F = 7.98, P = 0.006) and shorter hospital stays (4.10 ± 1.39 vs. 5.40 ± 1.22, P = 0.000) in the PNB group. There were no statistically significant differences in the length of the LMA pulled out, SBP or complications after 1 month between the groups. PNB optimizes the anaesthesia of nonintubated VATS.

Video-assisted thoracoscopic diaphragmatic plication.

The authors demonstrate a video-assisted thoracoscopic surgical technique for diaphragmatic plication, which is used to treat acquired diaphragmatic paralysis resulting from injury to the phrenic nerve. The objective of the surgical procedure is to return the abdominal contents to their normal position and restore optimal lung expansion by reducing the size of the diaphragmatic surface. Successful diaphragmatic plication improves lung function, reduces dyspnea, and restores quality of life.

Phrenic Nerve Block at the Azygos Vein Level Versus Sham Block for Ipsilateral Shoulder Pain After Video-Assisted Thoracoscopic Surgery: A Randomized Controlled Trial.

BACKGROUND: Ipsilateral shoulder pain (ISP) is a common problem after pulmonary surgery. We hypothesized that phrenic nerve block (PNB) at the azygos vein level, near the location of the surgical operation, would be effective for reducing ISP. Our primary aim was to assess the effect of PNB on postoperative ISP, following video-assisted thoracic surgery (VATS). METHODS: This prospective, randomized, patient-blinded, single-institution trial was registered at the University Hospital Medical Information Network (UMIN000030464). Enrolled patients had been scheduled for VATS under general anesthesia with epidural analgesia. Patients were randomly allocated to receive infiltration of the ipsilateral phrenic nerve at the azygos vein level with either 10 mL of 0.375% ropivacaine (PNB group) or 0.9% saline (control group) before chest closure. Postoperative ISP was assessed using a numerical rating scale (NRS, 0-10) at rest at 2, 4, 8, 16, and 24 hours. The incidence of ISP was defined as the proportion of patients who reported an NRS score of ≥1 at least once within 24 hours after surgery. In the primary analysis, the proportion of patients with ISP was compared between PNB and control groups using the χ2 test. NRS values of ISP and postoperative incision pain within 24 hours were investigated, as was the frequency of postoperative analgesic use. Incision pain was assessed using an NRS at the time of ISP assessment. Finally, the incidence of postoperative nausea and vomiting and shoulder movement disorders were also evaluated. RESULTS: Eighty-five patients were included, and their data were analyzed. These patients were randomly assigned to either PNB group (n = 42) or control group (n = 43). There were no clinically relevant differences in demographic and surgical profiles between the groups. There was no significant difference in the incidence of ISP (the control group 20/43 [46.5%] versus the PNB group 14/42 [33.3%]; P = .215). The severity of ISP was lower in the PNB group than in the control group (linear mixed-effects model, the main effect of treatment [groups]: P < .001). There were no significant differences between groups in terms of postoperative incision pain. The frequency of postoperative analgesic use was significantly higher in the control group (Wilcoxon rank sum test, P < .001). Postoperative nausea and vomiting did not significantly differ between the 2 groups. There were no changes in the range of shoulder joint movement. CONCLUSIONS: Azygos vein level PNB did not significantly affect the incidence of ISP after VATS.