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Clinical Anatomy (New York, N.Y.) Nov 2017The accessory phrenic nerve (APN) is a common anatomical variant with differing reports of prevalence in the literature. It can be injured during operative procedures to... (Meta-Analysis)
Meta-Analysis Review
The accessory phrenic nerve (APN) is a common anatomical variant with differing reports of prevalence in the literature. It can be injured during operative procedures to the neck and thorax or by regional anesthetic techniques in its vicinity. Our aim was to provide a comprehensive evidence-based assessment of the prevalence and origins of the APN. The databases PubMed, China National Knowledge Infrastructure, ScienceDirect, EMBASE, BIOSIS, SciELO, and Web of Science were searched comprehensively, followed by assessment of eligibility and extraction of data concerning the APN. The data were pooled into a meta-analysis. A total of 17 studies were included in the meta-analysis. Fourteen studies (n = 1,941 hemi-necks) reported data on APN prevalence resulting in an overall pooled prevalence estimate of 36.5%. Nine studies (n = 941 APNs) reported data on the origin of the APN. Most commonly the APN originated from the ansa cervicalis (16.5%) followed by the nerve to the subclavius (15.8%). Subgroup analysis on the basis of laterality and geographic region revealed no statistically significant findings. The APN is a highly variable anatomical structure present in over one third of the population, most often originating from the ansa cervicalis or the nerve to the subclavius. Clinicians need to be aware of the varying constellation of symptoms that can arise from APN injury. Ultimately, knowledge of APN variation could provide for better outcomes and reduction of iatrogenic injuries, particularly in high-risk patients prone to long-term complications from diaphragmatic dysfunction. Clin. Anat. 30:1077-1082, 2017. © 2017 Wiley Periodicals, Inc.
Topics: Cadaver; Humans; Phrenic Nerve
PubMed: 28726261
DOI: 10.1002/ca.22956 -
Sleep Medicine Clinics Dec 2020Neuralgic amyotrophy is a poorly understood neuromuscular disorder affecting peripheral nerves mostly within the brachial plexus distribution but can also involve other... (Review)
Review
Neuralgic amyotrophy is a poorly understood neuromuscular disorder affecting peripheral nerves mostly within the brachial plexus distribution but can also involve other sites including the phrenic nerve. In the classic form of the syndrome it causes proximal upper limb and neck pain on the affected side with subsequent muscle weakness that can be highly heterogeneous. Nocturnal noninvasive ventilation support is a first-line treatment after phrenic mononeuropathy. The regular monitoring of diaphragm function with spirometry and diaphragm ultrasound can help determine prognosis and inform decision-making.
Topics: Brachial Plexus Neuritis; Diaphragm; Humans; Noninvasive Ventilation; Phrenic Nerve
PubMed: 33131663
DOI: 10.1016/j.jsmc.2020.08.002 -
Muscle & Nerve Apr 2019Assessment of diaphragm compound muscle action potential by noninvasive phrenic nerve stimulation at the neck is well described. However, normal values in a large cohort...
INTRODUCTION
Assessment of diaphragm compound muscle action potential by noninvasive phrenic nerve stimulation at the neck is well described. However, normal values in a large cohort of healthy subjects are lacking. Our objective was to determine reference values of phrenic nerve conduction in healthy subjects.
METHODS
We recruited 155 healthy subjects (25-79 years old) and measured mean amplitude (PhrenAmp) and latency (PhrenLat) of motor responses according to Bolton's method.
RESULTS
The lower limit for PhrenAmp was 0.28 and 0.25 mV and the upper limit for PhrenLat was 8.41 and 8.56 ms for right and left side, respectively. PhrenLat was correlated with age. PhrenAmp, PhrenLat and area were significantly higher in men. Tolerance to phrenic nerve stimulation was excellent.
CONCLUSIONS
Our study provides normative values of phrenic nerve motor responses in a large cohort of healthy subjects and identifies age and sex as factors of variation. Muscle Nerve 59:451-456, 2019.
Topics: Adult; Aged; Aging; Cohort Studies; Electric Stimulation; Electromyography; Female; Healthy Volunteers; Humans; Male; Middle Aged; Neural Conduction; Phrenic Nerve; Reference Values; Respiratory Function Tests; Sex Characteristics
PubMed: 30623462
DOI: 10.1002/mus.26414 -
Physical Medicine and Rehabilitation... Aug 2014After cervical spinal cord injuries, many patients are unable to sustain independent ventilation because of a disruption of diaphragm innervation and respiratory... (Review)
Review
After cervical spinal cord injuries, many patients are unable to sustain independent ventilation because of a disruption of diaphragm innervation and respiratory functioning. If phrenic nerve function is preserved, the patient may be able to tolerate exogenous pacing of the diaphragm via electrical stimulation. Previously this was accomplished by stimulation directly to the phrenic nerves, but may be accomplished less invasively by percutaneously stimulating the diaphragm itself. The benefits, when compared with mechanical ventilation, include a lower rate of pulmonary complications, improved venous return, more normal breathing and speech, facilitation of eating, cost-effectiveness, and increased patient mobility.
Topics: Diaphragm; Electric Stimulation Therapy; Electrodes, Implanted; Humans; Patient Selection; Phrenic Nerve; Respiration; Spinal Cord Injuries; Ventilator Weaning
PubMed: 25064791
DOI: 10.1016/j.pmr.2014.04.004 -
Journal of Ultrasound in Medicine :... Feb 2022The diaphragm, the principle muscle of inspiration, is an under-recognized contributor to respiratory disease. Dysfunction of the diaphragm can occur secondary to lung... (Review)
Review
The diaphragm, the principle muscle of inspiration, is an under-recognized contributor to respiratory disease. Dysfunction of the diaphragm can occur secondary to lung disease, prolonged ventilation, phrenic nerve injury, neuromuscular disease, and central nervous system pathology. In light of the global pandemic of coronavirus disease 2019 (COVID-19), there has been growing interest in the utility of ultrasound for evaluation of respiratory symptoms including lung and diaphragm sonography. Diaphragm ultrasound can be utilized to diagnose diaphragm dysfunction, assess severity of dysfunction, and monitor disease progression. This article reviews diaphragm and phrenic nerve ultrasound and describes clinical applications in the context of COVID-19.
Topics: COVID-19; Diaphragm; Humans; Phrenic Nerve; SARS-CoV-2; Ultrasonography
PubMed: 33772850
DOI: 10.1002/jum.15706 -
Annals of Anatomy = Anatomischer... Jun 2024The aim of this systematic review is to study the subdiaphragmatic anatomy of the phrenic nerve. (Review)
Review
OBJECTIVE
The aim of this systematic review is to study the subdiaphragmatic anatomy of the phrenic nerve.
MATERIALS AND METHODS
A computerised systematic search of the Web of Science database was conducted. The key terms used were phrenic nerve, subdiaphragmat*, esophag*, liver, stomach, pancre*, duoden*, intestin*, bowel, gangli*, biliar*, Oddi, gallbladder, peritone*, spleen, splenic, hepat*, Glisson, falciform, coronary ligament, kidney, suprarenal, and adrenal. The 'cited-by' articles were also reviewed to ensure that all appropriate studies were included.
RESULTS
A total of one thousand three hundred and thirty articles were found, of which eighteen met the inclusion and exclusion criteria. The Quality Appraisal for Cadaveric Studies scale revealed substantial to excellent methodological quality of human studies, while a modified version of the Systematic Review Centre for Laboratory Animal Experimentation Risk of Bias Tool denoted poor methodological quality of animal studies. According to human studies, phrenic supply has been demonstrated for the gastro-esophageal junction, stomach, celiac ganglia, liver and its coronary ligament, inferior vena cava, gallbladder and adrenal glands, with half of the human samples studied presenting phrenic nerve connections with any subdiaphragmatic structure.
CONCLUSIONS
This review provides the first systematic evidence of subdiaphragmatic phrenic nerve supply and connections. This is of interest to professionals who care for people suffering from neck and shoulder pain, as well as patients with peridiaphragmatic disorders or hiccups. However, there are controversies about the autonomic or sensory nature of this supply.
Topics: Phrenic Nerve; Humans; Diaphragm; Animals
PubMed: 38692333
DOI: 10.1016/j.aanat.2024.152269 -
Europace : European Pacing,... Apr 2023
Topics: Humans; Atrial Fibrillation; Phrenic Nerve; Echocardiography; Pericardium
PubMed: 37061851
DOI: 10.1093/europace/euad054 -
Muscle & Nerve Jan 2024Phrenic nerve conduction studies (NCSs) and needle electromyography (EMG) can provide important information on the underlying pathophysiology in patients presenting with... (Review)
Review
Phrenic nerve conduction studies (NCSs) and needle electromyography (EMG) can provide important information on the underlying pathophysiology in patients presenting with unexplained shortness of breath, failure to wean from the ventilator, or consideration of phrenic nerve pacemaker implantation. However, these techniques are often technically challenging, require experience, can lack sensitivity and specificity, and, in the case of diaphragm EMG, involve some degree of risk. Diagnostic high-resolution ultrasound has been introduced in recent years as an adjuvant technique readily available at the bedside that can increase the overall sensitivity and specificity of the neurophysiologic evaluation of respiratory symptoms. Two-dimensional ultrasound in the zone of apposition can identify atrophy and evaluate contractility of the diaphragm, in addition to localizing a safe zone for needle EMG. M-mode ultrasound can identify decreased excursion or paradoxical motion of the diaphragm and can increase the reliability of phrenic NCSs. When used in combination, ultrasound, phrenic NCSs and EMG of the diaphragm can differentiate neuropathic, myopathic, and central disorders, and can offer aid in prognosis that is difficult to arrive at solely from clinical examination. This article will review techniques to successfully perform phrenic NCSs, needle EMG of the diaphragm, and ultrasound of the diaphragm. The discussion will include technical pitfalls and clinical pearls as well as future directions and clinical indications.
Topics: Humans; Reproducibility of Results; Electromyography; Dyspnea; Diaphragm; Peripheral Nervous System Diseases; Phrenic Nerve
PubMed: 37975205
DOI: 10.1002/mus.27998 -
World Neurosurgery Nov 2022Phrenic nerve dysfunction has been associated with cervical neuroforaminal stenosis in limited case reports and case-controlled studies. It is unclear if magnetic... (Review)
Review
BACKGROUND
Phrenic nerve dysfunction has been associated with cervical neuroforaminal stenosis in limited case reports and case-controlled studies. It is unclear if magnetic resonance imaging of the cervical spine should be included in the workup of patients with pulmonary dysfunction. A systematic review of the current literature was conducted on the topic to provide an outline of the body of knowledge and some guidance for neurosurgeons that receive these patient referrals.
METHODS
A systematic literature review was conducted through the PubMed database to identify articles related to phrenic nerve dysfunction secondary to cervical stenosis.
RESULTS
A total of 12 case reports were found. The median subject age was 64 years, 11 were male. Presenting symptoms included shortness of breath (n = 9), radiculopathy (n = 7), myelopathy (n = 5), reduced pulmonary function (n = 6), weakness (n = 4), and neck pain (n = 5). Ten of these patients underwent surgical intervention, all having improvements in their pulmonary and neurological symptoms at follow-up ranging from 10 days to 2 years.
CONCLUSIONS
Cervical stenosis, resulting in neuroforaminal stenosis, may be related to phrenic nerve dysfunction in select patients with idiopathic diaphragmatic paralysis or pulmonary dysfunction. Surgical decompression improves pulmonary and neurological symptoms.
Topics: Humans; Male; Middle Aged; Female; Constriction, Pathologic; Phrenic Nerve; Spinal Cord Diseases; Cervical Vertebrae; Respiratory Paralysis
PubMed: 36089276
DOI: 10.1016/j.wneu.2022.09.009 -
Circulation. Arrhythmia and... Jun 2022Phrenic nerve palsy is a well-known complication of cardiac ablation, resulting from the application of direct thermal energy. Emerging pulsed field ablation (PFA) may...
BACKGROUND
Phrenic nerve palsy is a well-known complication of cardiac ablation, resulting from the application of direct thermal energy. Emerging pulsed field ablation (PFA) may reduce the risk of phrenic nerve injury but has not been well characterized.
METHODS
Accelerometers and continuous pacing were used during PFA deliveries in a porcine model. Acute dose response was established in a first experimental phase with ascending PFA intensity delivered to the phrenic nerve (n=12). In a second phase, nerves were targeted with a single ablation level to observe the effect of repetitive ablations on nerve function (n=4). A third chronic phase characterized assessed histopathology of nerves adjacent to ablated cardiac tissue (n=6).
RESULTS
Acutely, we observed a dose-dependent response in phrenic nerve function including reversible stunning (R=0.965, <0.001). Furthermore, acute results demonstrated that phrenic nerve function responded to varying levels of PFA and catheter proximity placements, resulting in either: no effect, effect, or stunning. In the chronic study phase, successful isolation of superior vena cava at a dose not predicted to cause phrenic nerve dysfunction was associated with normal phrenic nerve function and normal phrenic nerve histopathology at 4 weeks.
CONCLUSIONS
Proximity of the catheter to the phrenic nerve and the PFA dose level were critical for phrenic nerve response. Gross and histopathologic evaluation of phrenic nerves and diaphragms at a chronic time point yielded no injury. These results provide a basis for understanding the susceptibility and recovery of phrenic nerves in response to PFA and a need for appropriate caution in moving beyond animal models.
Topics: Animals; Atrial Fibrillation; Catheter Ablation; Peripheral Nerve Injuries; Phrenic Nerve; Pulmonary Veins; Swine; Vena Cava, Superior
PubMed: 35649121
DOI: 10.1161/CIRCEP.121.010127