Part 2: Birth trauma: injuries to the intraabdominal organs, peripheral nerves, and skeletal system

Part 1 of this 2-part article, "Early Recognition and Treatment of Birth Trauma: Injuries to the Head and Face" provided readers with basic concepts related to birth trauma to the head and face. Part 2 focuses on the pathophysiology, etiology, diagnosis, treatment, and prognosis of birth injuries to the intraabdominal organs, the peripheral nerves, the spinal cord, and the skeletal system. Risk factors for birth injury to these areas are discussed along with key issues related to the nursing care of affected infants.

Supraclavicular Total Scalenectomy with or without First Rib Resection: Technic and Results

This describes the clinical picture of neurogenic TOS, supraclavicular surgical technique, and results of surgery as well as surgical complications.

N-ACETYLCYSTEINE PROTECTS THE RATS AGAINST PHRENIC NERVE DYSFUNCTION IN SEPSIS

This study investigates the association of oxidative stress with the function of the phrenic nerve and inquires whether N-acetylcysteine (NAC) may counteract the possible detrimental effects. Thirty rats were divided into three groups: sham, cecal ligation and puncture (CLP), and CLP plus NAC treatment. Sepsis was produced by the CLP procedure. NAC was administered at 70 mg/day for 7 days. Electrophysiology was evaluated by the needle electromyography of the diaphragm and phrenic nerve conduction study. Oxidative stress was evaluated by malondialdehyde (MDA), nitrite/nitrate (NN), and reduced-glutathione (ReGSH) levels and myeloperoxidase (MPO) and catalase (CAT) activities in the phrenic nerve. In the CLP group, ReGSH and CAT were decreased (P = 0.0001, P = 0.07, respectively); and MDA, MPO, and NN were increased (P = 0.02, P = 0.0001, P = 0.043, respectively), compared with the sham group. NAC administration increased the ReGSH (P = 0.036) and decreased the MDA, MPO, and NN (P = 0.008, P = 0.01, P = 0.032, respectively), compared with the CLP group. In the CLP group, electrophysiology revealed reductions in the number of motor unit action potentials (P = 0.0001) and prolongations in the latency of the compound nerve action potential (P = 0.0001), indicating phrenic nerve neuropathy. NAC administration significantly ameliorated these electrophysiological alterations (P = 0.011, P = 0.0001, respectively), compared with the CLP group. The present results showed that intraabdominal sepsis is closely associated with phrenic nerve neuropathy. In addition, NAC administration protects the rats against the detrimental events of sepsis.

Mechanisms of Phrenic Nerve Injury During Radiofrequency Ablation at the Pulmonary Vein Orifice

BACKGROUND

The phrenic nerve can be injured with radiofrequency energy delivery. Nevertheless, the mechanisms of injury are unknown. This study was undertaken to examine phrenic nerve tissue temperatures during ablation at the pulmonary vein (PV) orifice, assess the temperature dependence of injury, and to delineate the possible mechanisms of untoward nerve effects.

METHODS

Ten dogs underwent ablation at the right superior PV (RSPV) orifice. Phrenic nerve temperatures were assessed with implanted thermocouples overlying the endocardial ablation site. Using an 8-mm ablation catheter tip, energy was titrated to 50 degrees C and incremented by 5 degrees C for 120 seconds.

RESULTS

Phrenic nerve capture was achieved in nine (90%) dogs after thermocouple implantation. A RSPV orifice tissue temperature >60 degrees C occurred in 32 (84%) of energy deliveries with a power of 34 +/- 22 W. In three (33%) dogs, this resulted in nerve dysfunction (maximum nerve temperature: 41 degrees C, 41 degrees C, and 91 degrees C) with histology consistent with acute thermal injury. In four additional dogs, 17 energy deliveries were made directly to the phrenic nerve using a novel in situ model. In 5 (29%) energy deliveries, nerve function was impacted immediately by the generated current, with resolution simultaneous with discontinuing radiofrequency. Transient phrenic nerve injury occurred in all dogs at a temperature of 47 +/- 3 degrees C (range: 43-53 degrees C) after 38 +/- 32 seconds (range: 20-120 seconds). After termination of the energy delivery, nerve function returned in 15(88%) during 30 seconds of postablation pacing. In two (12%) ablation attempts, nerve recovery was delayed (>3 minutes). Permanent injury occurred in all dogs after 92 +/- 83 seconds (range: 20-280 seconds) of additional energy delivery at a temperature of 51 +/- 6 degrees C (range: 45-65 degrees C).

CONCLUSION

Phrenic nerve injury can be more common than anticipated with RF ablation at the RSPV orifice. Relatively low tissue temperatures can injure the nerve. Immediate nerve effects suggest a second mechanism of nerve dysfunction related to electrical current. Transient nerve effects occur prior to permanent damage, providing an opportunity to discontinue energy delivery before permanent injury.

How close are the phrenic nerves to cardiac structures? Implications for cardiac interventionalists

BACKGROUND

Phrenic nerve injury is a recognized complication following cardiac intervention or surgery. With increasing use of transcatheter procedures to treat drug-refractory arrhythmias, clarification of the spatial relationships between the phrenic nerves and important cardiac structures is essential to reduce risks.

METHODS AND RESULTS

We examined by gross dissection the courses of the right and left phrenic nerves in 19 cadavers. Measurements were made of the minimal and maximal distances of the nerves to the superior caval vein, superior cavoatrial junction, right pulmonary veins, and coronary veins. Histologic studies were carried out on tissues from six cavaders. Tracing the course of the right phrenic nerve revealed its close proximity to the superior caval vein (minimum 0.3 +/- 0.5 mm) and the right superior pulmonary vein (minimum 2.1 +/- 0.4 mm). The anterior wall of the right superior pulmonary vein was <2 mm from the right phrenic nerve in 32% of specimens. The left phrenic nerve passed over the obtuse cardiac margin and the left obtuse marginal vein and artery in 79% of specimens. In the remaining specimens, its course was anterosuperior, passing over the main stem of the left coronary artery or the anterior descending artery and great cardiac vein.

CONCLUSIONS

The right phrenic nerve is at risk when ablations are carried out in the superior caval vein and the right superior pulmonary vein. The left phrenic nerve is vulnerable during lead implantation into the great cardiac and left obtuse marginal veins.

Surgical treatment of diaphragmatic eventration using video-assisted thoracic surgery: a prospective study

BACKGROUND

This study seeks to evaluate results regarding the repair of diaphragmatic eventration using video-assisted thoracic surgery (VATS).

METHODS

We performed a prospective observational study including patients referred to us for surgical treatment of diaphragmatic eventration during a 12-year period. Clinical, radiologic, and functional data were prospectively recorded. VATS was performed with two thoracoports and a 4-cm mini-thoracotomy. Diaphragmatic plication was performed using two nonresorbable running sutures from periphery to the cardio-phrenic angle. Follow-up data (clinical examination, chest roentgenogram, lung function tests at 3, 6, 12 months, and annually thereafter) were also prospectively recorded.

RESULTS

Twelve patients (4 male adults, mean age 57.7 +/- 14.8 years) were operated on between 1992 and 2003. The left side was involved in 8 patients and the mean height of diaphragm elevation was 7.5 +/- 1.8 cm. All patients experienced symptoms related to the disease; in 2 patients the operation was carried out to achieve weaning from mechanical ventilation. The etiologic mechanism could be identified in 11 out of 12 patients (trauma, n = 9; Charcot-Marie disease, n = 1; calcified para-aortic nodes, n = 1). Mean operative time, drainage output, and hospital stay were 77 +/- 15 minutes, 0.8 +/- 04 L, and 3.4 +/- 0.7 days, respectively. No mortality was observed; 1 patient experienced postoperative pneumonia, which was treated using antibiotics. All patients experienced amelioration of symptoms and long-term lung function tests revealed a marked improvement of both the forced volume capacity and the forced expiratory volume at 1 second. No relapses were observed at follow-up chest roentgenogram.

CONCLUSIONS

Treatment using VATS is a safe and effective alternative to conventional surgery. Functional improvement persists at long-term follow-up.

Paralysis of the phrenic nerve as a risk factor for suboptimal Fontan hemodynamics

OBJECTIVE

The introduction of the Fontan operation for single ventricle physiology was based on the dual principle of the pulmonary blood flow. It is postulated that normal breathing movements are necessary for passive blood flow into the lungs. We compared patients with and without palsy of the phrenic nerve regarding the sufficiency of Fontan hemodynamics.

METHODS

We analyzed 85 consecutive patients, who were available for follow-up after completion of their total cavopulmonary connection (TCPC) between February 1992 and February 2003. The median age at TCPC completion was 4.3 (range 1.3-37) years. Sixty were operated on with an extracardiac conduit and 25 with a lateral tunnel. Fifty patients underwent postoperative heart catheterization with contrast angiography. The diagnosis of diaphragm paralysis was made using echocardiography, fluoroscopy and X-ray examination. Surgical diaphragm plication was performed in 13 patients (Four before and nine after Fontan operation) at a median of 2.2 years after the diagnosis.

RESULTS

Twenty-one patients developed fixed palsy of the phrenic nerve during a total of 225 operations before and including completion of TCPC. There were no differences in the incidence of phrenic nerve paralysis between small children (aged <3 years) and older patients or between patients with the extracardiac and intracardiac Fontan procedures. There were no differences in the duration of mechanical ventilation. However, prolonged pleural effusions and a hospital stay of longer than 2 weeks were noted more frequently in patients with palsy (P<0.05). During the median follow-up of 4.6 (range: 0.7-11.4) years significantly more patients with phrenic nerve palsy developed chronic ascites compared to those without palsy (8 of 20 vs. 2 of 65; P<0.001).

CONCLUSIONS

Phrenic nerve palsy was recognized as a risk factor for suboptimal Fontan hemodynamics due to the hindrance of passive venous blood flow. Patients with phrenic nerve palsy have a longer hospital stay and a higher incidence of prolonged pleural effusions and of chronic ascites, than those without. Early diaphragm plication may be favorable to optimize the Fontan circuit in these patients. Completion of the TCPC in patients with diaphragm paralysis should be viewed critically.

Phrenic nerve injury after blunt trauma

Phrenic nerve injury resulting from blunt trauma is unusual and may closely mimic diaphragmatic rupture. Diagnosis remains difficult and is often delayed. A prompt diagnosis requires a high index of suspicion. We describe one patient with phrenic nerve injury in whom the diagnosis was made late at the time of injury. Radiograph, ultrasonography, and computed tomography were helpful in the diagnosis. Video-assisted thoracic surgery was performed on our patient for diagnostic purposes. Left phrenic nerve injury and pericardial injury were found. Diaphragmatic plication was performed through a miniature left posterolateral thoracotomy. This case was presented to show the unusual nature of phrenic nerve injury.

[Diaphragmatic paralysis after cardiac surgery in children: value of plication]

Phrenic nerve injury is a recognized and severe complication after cardiac surgery. Diaphragmatic paralysis leads to difficulty of weaning the child from the ventilator surgical plication is an easy and safe procedure that result in early clinical and physiological improvements.

Augmented breath phase volume and timing relationships in the anesthetized rat

Augmented breaths (ABs), or sighs, are airway protective reflexes and part of the normal repertoire of respiratory behaviors. ABs consist of two phases, where phase I volume and timing resembles preceding eupnic breaths, and phase II is an augmenting motor pattern and occurs at the end of phase I. Recent evidence suggest multiple respiratory motor patterns can occur following dynamic functional reconfiguration of one respiratory neural network. It follows that the response of the respiratory network to modulatory inputs also may undergo dynamic reconfiguration. We hypothesized that lung-volume related feedback during ABs would alter AB timing differentially during phase I and II. We measured phase I and II volumes and durations in urethane anesthetized rats with decreased lung volume secondary to three models of varying phrenic motor impairment (spinal injury alone, unilateral phrenicotomy, and combined injuries). AB phase I and II inspired volume were decreased after phrenic motor impairment (p<0.05). In contrast, only phase I duration following injury was altered compared to controls. Phase II duration remaining unchanged despite the greatest effect of injury on volume occurring during phase II. Thus, sigh volume-timing relationships differ between phases of an augmented breath suggesting that the response of the respiratory network to modulatory inputs has changed. These data support the hypothesis that multiple respiratory behaviors occur following dynamic reconfiguration of the respiratory neural network.

Combination of diaphragmatic plication with major abdominal surgery in patients with phrenic nerve palsy

The role of simultaneous prophylactic diaphragmatic plication during major abdominal operations is evaluated. In five patients with a history of phrenic nerve injury, postoperative ventilation requirements and hospital stay were significantly reduced when synchronous diaphragmatic plication was performed, compared with corresponding values obtained during previous abdominal operation without diaphragmatic plication. In addition, diaphragmatic plication was associated with postoperative improvement of respiratory mechanics and blood gas exchange.

Incidence and treatment of diaphragmatic paralysis after cardiac surgery in children

OBJECTIVE

Diaphragmatic paralysis (DP) caused by phrenic nerve injury is potentially life-threatening in infants. Phrenic nerve injury due to thoracic surgery is the most common cause of DP in children. We retrospectively analyzed incidence, surgical details, management and follow-up of our patients with DP after cardiac surgery to develop an algorithm for the management and follow-up.

METHODS

Retrospective analysis of 43 patients with DP after cardiac surgery performed between 1996 and 2000.

RESULTS

Median age at cardiac surgery was 1 month (range 3 days to 9 years). Incidence of DP was 5.4%. A trend towards higher incidences of DP were observed after arterial switch operation (10.8%, P=0.18), Fontan procedure (17.6%, P=0.056) and Blalock-Taussig Shunt (12.8%, P=0.10). Median time from cardiac surgery to surgical plication was 21 days (range 7-210 days). Transthoracic diaphragmatic plication was performed in 29/43 patients, no plication was done in 14/43 patients. Patients in whom diaphragmatic plication was required were younger (median age 2 months, range 21 days to 53 months versus 17.5 months, range 4 days to 110 months; P<0.001). Indications for plication were failure to wean from ventilator (n=22), respiratory distress (n=4), cavopulmonary anastomosis (n=2), and failure to thrive (n=1). All these symptoms resolved after diaphragmatic plication, however, 8/29 patients with plication and 2/14 without plication died. Cause of death was not related to diaphragmatic plication in any patient. Position of plicated diaphragm was normal in 18/21 surviving patients 1 month after plication. In 2/12 surviving patients without plication hemidiaphragm showed a normal position 1 year after surgery. The rate of pulmonary infections was not significantly different during 12-60 months follow-up.

CONCLUSIONS

DP is an occasional complication of cardiac surgery. High incidences of DP were seen after arterial switch operation, Fontan procedure and Blalock-Taussig shunt (BT). Respiratory insufficiency requires diaphragmatic plication in most infants with DP whereas older children may tolerate DP. Transthoracic diaphragmatic plication is an effective treatment of DP and achieves relief of respiratory insufficiency in most patients. Spontaneous recovery from postsurgical DP is rare.

The prevention of nerve injury in aortic arch aneurysmal surgery

In a case of aortic arch aneurysm associated with adhesion to the surrounding structures, we devised an operative technique to avoid nerve injury during the surgical procedure. By preserving the adventitial layer of the aortic arch aneurysm to which the phrenic and recurrent nerves were attached, injury to the nerves was avoided, and the aneurysmectomy was completed with the distal anastomosis being performed intraluminally.

Prolonged hemidiaphragmatic paralysis following interscalene brachial plexus block

We present a case of persistent phrenic nerve paralysis after a successful interscalene brachial plexus block. In addition, there was no observed diaphragmatic stimulation, and the patient underwent an uneventful early postoperative period. Warning signs of a complication were either missed or absent until several days after discharge from the ambulatory surgical unit.

Right Phrenic Nerve Injury Following Electrical Disconnection of the Right Superior Pulmonary Vein

This report describes a case of transient paresis of the right diaphragm following the transcatheter radiofrequency ablation for the electrical disconnection of pulmonary veins, which recovered completely during the observational period in a 61-year-old woman with paroxysmal atrial fibrillation. For electrical disconnection of pulmonary veins, careful preventive measures for phrenic nerve damage are required.

Unilateral diaphragmatic paralysis following thoracic outlet surgery: a case report

In this report, a young female, who initially presented with left upper extremity pain, eventually underwent surgery for presumed thoracic outlet syndrome. Following surgery, she developed shortness of breath. Diagnostic studies revealed an elevated left hemidiaphragm secondary to injury to the phrenic nerve.