Right hemi-diaphragm paralysis following cardiac radiofrequency ablation

[Neuralgic amyotrophy: a common cause of unilateral and bilateral diaphragmatic pareses]

There are several causes for unilateral or bilateral diaphragmatic paresis. The most common cause is an (intraoperative) injury to the phrenic nerve.However, in up to 20% of cases, no explanation can be found despite extensive workup. Neuralgic amyotrophy (NA, also known as Parsonage-Turner syndrome) is a common underdiagnosed multifocal autoimmune-inflammatory disease that predominantly affects proximal nerve segments of the upper extremities. Classic symptoms include acute onset of severe pain in the shoulder girdle with delayed onset of paresis of the shoulder and arm muscles. In at least 7% of cases, the phrenic nerve is also affected. Based on the annual incidence of NA of 1:1000, the entity as a cause of diaphragmatic dysfunction is probably not as uncommon as previously thought. However, clinical experience shows that this diagnosis is often not considered, and diaphragmatic paresis gets wrongly classified as idiopathic.This is particularly disastrous because in the early stage of NA, medical therapy with corticosteroids is mostly not considered and the possibility that surgical repair of the diaphragm may be performed prematurely, given that the condition may resolve spontaneously many months after symptom onset.The aim of the present article is to raise awareness of the entity of NA as a cause of diaphragmatic paresis and to establish a standardized approach to diagnosis and treatment.

Phrenic nerve paralysis after bipolar electrocoagulation of endometriosis of the diaphragm: case report and mini review

Objective

To present a case of persistent postoperative elevation of the right hemidiaphragm after bipolar electrocoagulation of diaphragmatic endometriosis, highly likely because of collateral thermal damage to key branches of the phrenic nerve, and review the literature on diaphragmatic endometriosis, focusing on operative treatment.

Design

Case report and mini review.

Setting

Single university-based interdisciplinary endometriosis center.

Patient(s)

A 33-year-old nulliparous patient, initially presenting with right-sided shoulder and back pain accompanied by severe dysmenorrhea and diarrhea. Written consent for the use of anonymized data and images for research purposes was obtained.

Intervention(s)

Laparoscopic surgery with bipolar electrocoagulation of multiple superficial endometriotic lesions on the right hemidiaphragm and excision of bilateral deep infiltrating endometriosis on the sacrouterine ligaments.

Main Outcome Measure(s)

Outcome and complication of surgical treatment of diaphragmatic endometriosis.

Result(s)

Three weeks after surgical treatment, the patient complained of exertional dyspnea and pain in the right flank. Imaging showed a postoperative elevation of the right hemidiaphragm, which did not resolve over the following 6 months. We suspect collateral thermal damage to key branches of the phrenic nerve after bipolar electrocoagulation of extensive superficial diaphragmatic lesions.

Conclusion(s)

During laparoscopic treatment of diaphragmatic endometriosis, bipolar electrocoagulation should be used sparingly and with caution to avoid potentially damaging the phrenic nerve.

Phrenic nerve paralysis and phrenic nerve reconstruction surgery

Phrenic nerve injury results in paralysis of the diaphragm muscle, the primary generator of an inspiratory effort, as well as a stabilizing muscle involved in postural control and spinal alignment. Unilateral deficits often result in exertional dyspnea, orthopnea, and sleep-disordered breathing, whereas oxygen or ventilator dependency can occur with bilateral paralysis. Common etiologies of phrenic injuries include cervical trauma, iatrogenic injury in the neck or chest, and neuralgic amyotrophy. Many patients have no identifiable etiology and are considered to have idiopathic paralysis. Diagnostic evaluation requires radiographic and pulmonary function testing, as well as electrodiagnostic assessment to quantitate the nerve deficit and determine the extent of denervation atrophy. Treatment for symptomatic diaphragm paralysis has traditionally been limited. Medical therapies and nocturnal positive airway pressure may provide some benefit. Surgical repair of the nerve injury to restore functional diaphragmatic activity, termed phrenic nerve reconstruction, is a safe and effective alternative to static repositioning of the diaphragm (diaphragm plication), in properly selected patients. Phrenic nerve reconstruction has increasingly become a standard surgical treatment for diaphragm paralysis due to phrenic nerve injury. A multidisciplinary approach at specialty referral centers combining diagnostic evaluation, surgical treatment, and rehabilitation is required to achieve optimal long-term outcomes.

Significant diaphragm elevation suggestive of phrenic nerve injury after thoracoscopic lobectomy for lung cancer: an underestimated problem

Background

Phrenic nerve injury (PNI) during lung cancer surgery, without apparent nerve section or damage, is still not well-studied. The aim of our study is to find an easy and objective way to evaluate a significant diaphragm elevation (SDE) suggestive of inadvertent PNI and its incidence and impact on lung cancer patients undergone video-assisted thoracoscopic surgery (VATS) lobectomy.

Methods

Extent of diaphragm elevation was first examined on chest X-ray in a cohort of patients with invasive thymoma in whom phrenic nerve was intentionally transected. The result was then used as the criterion to diagnose a SDE suggestive of PNI in another cohort of VATS lobectomy patients. Fluoroscopy test was used to validate the results. Spirometry test was repeated to evaluate pulmonary function loss after surgery.

Results

Diaphragm elevation was 24.24%±6.2% in 22 invasive thymoma-patients, with 30% elevation adopted as the criterion to diagnose SDE suggestive of PNI. In 753 VATS lobectomy patients, 56 (7.4%) were diagnosed of SDE. On Fluoroscopy test, diaphragm movement was significantly less in patients with diaphragm elevation >30% than those without (5.0 vs. 11.0 mm, P=0.003), together with a significantly smaller diaphragm movement ratio on the operation (OP) side than on the contralateral side (17% vs. 42%, P=0.018). Although no difference in postoperative complications was found, reduction in FEV1, FVC, and DLCO was significantly greater in patients with a SDE than those without (P=0.009).

Conclusions

Patients with more than 30% diaphragm elevation after VATS lobectomy is highly likely to have PNI and should undergo fluoroscopic validation. Inadvertent PNI during VATS lobectomy is an underestimated phenomenon and is associated with significantly greater loss of pulmonary function.

Stimulation Mapping of the Pulmonary Artery for Denervation Procedures: an Experimental Study

Transcatheter pulmonary artery denervation (PADN) has been developed for the correction of pulmonary hypertension. We investigated pulmonary artery stimulation mapping and its role in PADN procedures. Artery stimulation was performed in 17 Landrace pigs. Low-frequency stimulation defined areas of ventricular and atrial capture. High-frequency stimulation evoked the following responses: sinus rhythm slowing and/or atrial rhythm acceleration in 59% of animals, phrenic nerve capture in 100%, and laryngeal recurrent nerve capture in 23%. The sites with evoked heart rate responses were marked by discrete radiofrequency ablations (RFA). An autopsy showed nerves in the adventitia and perivascular fat under the RFA sites, and the lack of muscarinic-1, tyrosine hydroxylase, and dopamine-5 receptors' expression. During PADN, areas adjacent to the course of phrenic and recurrent laryngeal nerves should be avoided. RFA at points with heart rate responses leads to the non-reproducibility of evoked reactions and the disappearance of neural markers' expression. Graphical abstract.

Pulmonary Vein Isolation with the Multipolar nMARQ™ Ablation Catheter: Efficacy And Safety In Acute And Long-Term Follow Up

Pulmonary vein isolation (PVI) is an established therapy for atrial fibrillation (AF). One challenge in the catheter-based treatment of this arrhythmia is to develop an effective and safe ablation approach to achieve durable and consistent lesions around the PVs. The multipolar irrigated radiofrequency (RF) ablation catheter nMARQ^TM was designed as a single-shot device with the aim to achieve these goals. This article reviews the current literature with respect to acute- and long- term success rates after PVI with this circular mapping and ablation device. Furthermore, since this device recently became discredited to potential lethal complications, we will also focus on the data available on safety issues with this ablation system.

Phrenic nerve injury and diaphragmatic paralysis following pacemaker pulse generator replacement

Diaphragmatic paralysis (DP) is a common condition. It can be unilateral or bilateral and the diagnosis is usually based on a clinical and radiological findings. Bilateral diaphragmatic paralysis is usually symptomatic with dyspnea and acute respiratory failure while unilateral diaphragmatic paralysis is typically asymptomatic and when present, symptoms usually depend on the presence of underlying pulmonary or neurologic disease. DP can be the result of various chest conditions that affect the phrenic nerve such as tumors, vascular abnormalities or traumatic incidents during surgery as well as blunt or penetrating chest or neck injuries. We report a unique case of phrenic nerve injury and unilateral diaphragmatic paralysis secondary to pacemaker pulse generator replacement that was successfully treated with diaphragmatic plication.

The Phrenic Nerve And Atrial Fibrillation Ablation Procedures

Radiofrequency ablation is increasingly used as an option to optimally manage patients with symptomatic atrial fibrillation. Presently, ablationists strive to improve success rates, particularly with persistent atrial fibrillation, while simultaneously attempting to reduce complications. A well-recognized complication with atrial fibrillation ablation is injury to the phrenic nerve giving rise to diaphragmatic paresis and patient discomfort.Phrenic nerve damage may occur when performing common components of atrial fibrillation ablation including pulmonary and superior vena caval isolation. The challenge for ablationists is to successfully target the arrhythmogenic substrate while avoiding this complication. In order to do this, a thorough knowledge of phrenic nerve anatomy, points in the ablation procedure where nerve damage is more likely, and an understanding of the presently utilized techniques to avoid this complication is required. In addition, when this complication does arise, prompt recognition of its occurrence, knowledge of the natural history, and available methods for management are needed.In this review, we discuss the underlying anatomic principles, techniques of avoiding phrenic nerve damage, and presently available methods of diagnosing and managing this complication.

Perineural air injection as a means of prevention of thermal injury of the sciatic nerve during radio frequency ablation: a preliminary experimental study in rabbits

OBJECTIVE

The purpose of this study was to determine whether perineural air injection before radio frequency (RF) ablation of thigh muscles can minimize thermal injury to the sciatic nerve.

METHODS

Eighteen percutaneous RF ablation procedures were performed in the thighs of 9 rabbits (control, n = 9, right thigh; experimental, n = 9, left thigh) with an internally cooled electrode (1-cm active tip). In the control group, the tip of the electrode was located in posterior muscles 5 mm away from the sciatic nerve before ablation. In the experimental group, sonographically guided air injection into the perineural space was performed just before ablation. Animals were killed 7 days after ablation, and the presence or absence of pathologic changes of the sciatic nerves (axonal necrosis, myelin digestion, endoneurial fibrosis, perineurial fibrosis, and dystrophic calcification) in both groups were compared under an optical microscope.

RESULTS

Perineural air injection was achieved successfully with a single puncture in all rabbits in the experimental group. All of the pathologic findings were observed much more frequently in the control group, and the differences in the frequencies of axonal necrosis and myelin digestion of the sciatic nerve between the groups were clinically significant (P < .05).

CONCLUSIONS

Perineural air injection may be useful for reducing the frequency of thermal injury during RF ablation of lesions adjacent to nerves.