Phrenic nerve transfer to the musculocutaneous nerve for the repair of brachial plexus injury: electrophysiological characteristics

Phrenic nerve transfer is a major dynamic treatment used to repair brachial plexus root avulsion. We analyzed 72 relevant articles on phrenic nerve transfer to repair injured brachial plexus that were indexed by Science Citation Index. The keywords searched were brachial plexus injury, phrenic nerve, repair, surgery, protection, nerve transfer, and nerve graft. In addition, we per-formed neurophysiological analysis of the preoperative condition and prognosis of 10 patients undergoing ipsilateral phrenic nerve transfer to the musculocutaneous nerve in our hospital from 2008 to 201 3 and observed the electromyograms of the biceps brachii and motor conduc-tion function of the musculocutaneous nerve. Clinically, approximately 28% of patients had brachial plexus injury combined with phrenic nerve injury, and injured phrenic nerve cannot be used as a nerve graft. After phrenic nerve transfer to the musculocutaneous nerve, the regener-ated potentials ifrst appeared at 3 months. Recovery of motor unit action potential occurred 6 months later and became more apparent at 12 months. The percent of patients recovering ‘ex-cellent’ and ‘good’ muscle strength in the biceps brachii was 80% after 18 months. At 12 months after surgery, motor nerve conduction potential appeared in the musculocutaneous nerve in seven cases. These data suggest that preoperative evaluation of phrenic nerve function may help identify the most appropriate nerve graft in patients with an injured brachial plexus. The func-tional recovery of a transplanted nerve can be dynamically observed after the surgery.

Histological analysis and clinical observation of phrenic nerve cryotherapy following pulmonary resection

BACKGROUND： Residual postoperative pleural spaces （RPPS） are often encountered during pulmonary resection; this could adversely affect the outcome and prolong recovery. Nerve cryotherapy reduces postoperative complications and does not affect neural regeneration. However, it remains unclear whether nerve cryotherapy reduces RPPS occurrence following pulmonary resection.OBJECTIVE： To explore pathological changes in the phrenic nerve following exposure to -50℃ for various freezing times, and to explore the feasibility and efficacy of phrenic nerve cryotherapy following pulmonary resection based on animal experiment results.DESIGN, TIME AND SETTING： A comparative animal study was conducted at the Animal Experimental Center of General Hospital of Chinese PLA from January to June 2008. Based on results from the animal study, a randomized, controlled, clinical study was initiated at the Department of Thoracic Surgery of General Hospital of Chinese PLA between July 2008 and July 2009.PARTICIPANTS： A total of 160 patients undergoing lobectomy were selected at the Department of Thoracic Surgery of General Hospital of Chinese PLA from July 2008 to July 2009.METHODS： Animal experiment： 27 adult goats were randomly assigned to three groups （n = 9）.The phrenic nerves were frozen at -50 ℃ for 30, 60, and 90 seconds, respectively. Clinical study： 160 patients undergoing lobectomy were randomly assigned to two groups （n = 80）. In the cryoanalgesia group, patients received phrenic nerve cryotherapy; phrenic nerves were frozen above the capsula cordis for 60 seconds at -50 ℃ prior to chest closure. Patients in the control group did not receive cryotherapy.MAIN OUTCOME MEASURES： Pathological changes were observed at days 1, 30, and 60 following phrenic nerve cryotherapy. In the clinical study, RPPS incidence rate was regularly recorded. Respiratory function tests, including measured forced vital capacity and forced expiratory volume in 1 second, were regularly conducted post-surgically. The incidence of post-surgical infection complications and the average days of chest drainage and hospital stay were observed and recorded.RESULTS： Animal study： nerve damage progressively increased with prolonged freezing time at -50 ℃, and recovery time from damage gradually increased. Nerves, which were frozen for 30 and 60 seconds, recovered by 30 days, and all nerves completely recovered by 60 days. Clinical study： the RPPS incidence rate was significantly less in the cryoanalgesia group compared with the control group at 1, 5, 10, and 30 days following surgery （P〈0.05）. Simultaneously, phrenic nerve cryotherapy decreased the incidence rate of RPPS and shortened the average days of chest drainage and hospital stay in patients undergoing lobectomy （P〈0.05）. However, phrenic nerve cryotherapy did not affect forced vital capacity, forced expiratory volume in 1 second, and the incidence rate of post-surgical infection complications （P〉0.05）.CONCLUSION： Following phrenic nerve cryotherapy in the goat at -50℃, the phrenic nerve recovered to normal by 60 days. In the clinical study, phrenic nerve cryotherapy reduced the RPPS incidence rate, had no effect on pulmonary function, shortened hospital stay in patients undergoing lobectomy, and proved to be a safe, effective method.

Semi-skeletonized Internal Mammary Grafts and Phrenic Nerve Injury:Cause-and-effect analysis

Summary： Phrenic nerve injury after cardiac surgery increases postoperative pulmonary complications. The purpose of this study was to analyze the causes and effects of phrenic nerve injury after cardiac surgery. Prospectively collected data on 2084 consecutive patients who underwent cardiac surgery from Jan. 1995 to Feb. 2002 were analyzed. Twenty-eight preoperative and operation related variables were subjected to logistic analysis with the end point being phrenic nerve injury. Then phrenic nerve injury and 6 perioperative morbidities were included in the analysis as variables to determine their independent predictive value for perioperative pulmonary morbidity. An identical approach was used to identify the independent risk factors for perioperative mortality. There were 53 phrenic nerve injuries （2.5 %）. There was no phrenic nerve injury in non-coronary surgery or coronary surgery using conduits other than the internal mammary artery. The independent risk factors for phrenic nerve injury were the use of internal mammary artery （Odds ratio （OR）=14.5） and the presence of chronic obstructive pulmonary disease （OR=2.9）. Phrenic nerve injury was an independent risk factor （OR=8.1） for perioperative pulmonary morbidities but not for perioperative mortality. Use of semi-skeletonized internal mammary artery harvesting technique and drawing attention to possible vascular or mechanical causes of phrenic nerve injury may reduce its occurrence. Unilateral phrenic nerve injury, although rarely life-threatening, is an independent risk factor for postoperative respiratory complications. When harvesting internal mammary arteries, it should be kept in mind avoiding stretching, compromising, or inadvertently dissecting phrenic nerve is as important as avoiding damage of internal mammary artery itself.

Character of diaphragm compound muscle action potential and phrenic nerve conduction time in patients with obstructive sleep apnea-hypopnea syndrome

BACKGROUND： Both hypoxia and.carbon dioxide retention can damage phrenic nerve and muscle conduction, as well as diaphragm function. Diaphragm compound muscle action potential and phrenic nerve conduction time are reliable indicators for measuring phrenic nerve and diaphragm function. OBJECTIVES： To verify the hypothesis that changes of phrenic nerve conduction time （PNCT） and diaphragm compound muscle action potential （CMAP） in obstructive sleep apnea-hypopnea syndrome （OSAHS） patients might contribute to the decline of phrenic nerve and diaphragm function. PNCT and CMAP were measured with multipair esophageal electrodes combined with unilateral magnetic stimulation. DESIGN, TIME AND SETTING： Case controlled study. The experiment was carried out in Guangzhou Institute of Respiratory Disease, Guangzhou MediCal College, from June 2005 to April 2006. PARTICIPANTS： Twenty seven OSAHS patients and eight primary snoring subjects from Guangzhou Institute of Respiratory Disease, Guangzhou Medical College were recruited and all subjects were diagnosed by polysomnography （PSG）. Sixteen healthy, non-snoring subjects in the hospital for medical examination during the same time period were selected as the control group. METHODS： Esophageal electrodes, made by Guangzhou Institute of Respiratory Disease, combined with unilateral magnetic stimulation, were used to measure PNCT and CMAP of all subjects. PNCT was defined as the time from stimulation artifact to the onset of CMAP and diaphragm CMAP amplitude was measured from peak to peak. Oxygen desaturation index and apnea-hypopnea index were measured using PSG, and their relevance to PNCT and CMAP were analyzed. PNCT and CMAP in five OSAHS patients were repeatedly measured after effective nasal continuous positive airway pressure treatment for more than 2 months. MAIN OUTCOME MEASURES： （1） PNCT and diaphragm CMAP of subjects in each group. （2） Relevance of oxygen desaturation index and apnea-hypopnea index to PNCT and CMAP. （3） Changes of PNCT and CMAP of OSAHS patients before and after treatment. RESULTS： All subjects were included in the analyzed results. （1） PNCT of the OSAHS group was significantly longer compared to that of the control and primary snore groups, while CMAP of the OSAHS group was significantly lower （P 〈 0.05）. （2） PNCT and CMAP recorded from both sides correlated significantly with oxygen desaturation index and with apnea-hypopnea index （P 〈 0.01 ）. （3） PNCT shortened significantly after effective nasal continuous positive airway pressure treatment for more than 2 months （ P 〈 0.05）. CONCLUSION： Prolongation of PNCT and decrease of CMAP might contribute to the decline of phrenic nerve and diaphragm function caused by repeated nocturnal hypoxia and carbon dioxide retention. The impairment of the phrenic nerve might also decrease diaphragm function.

Phrenic nerve displacement by intrapericardial balloon inflation during epicardial ablation of ventricular tachycardia: Four case reports

BACKGROUND Phrenic nerve(PN)injury is one of the recognized possible complications following epicardial ablation of ventricular tachycardia(VT).High-output pacing is a widely used maneuver to establish a relationship between the PN and the ablation catheter tip.An absence of PN capture is usually considered an indication that it is safe to ablate,and that successful ablation may be performed at adjacent sites.However,PN capture may impact the procedural outcome.Only a few cases have been reported in the literature that avoid PN injury by using different techniques.CASE SUMMARY Three patients with a previous history of myocarditis and one patient with ischemic cardiomyopathy underwent epicardial ablation for drug-refractory VT.Before the procedure,transthoracic echocardiogram,coronary angiogram,and cardiac magnetic resonance imaging were performed on all patients.Under general anesthesia,endo/epicardial three-dimensional anatomical and substrate maps of the left ventricle were accomplished.Before radiofrequency delivery,the course of the PN was identified by provoking diaphragmatic stimulation with high-output pacing from the distal electrode of the ablation catheter.In every case,a scar region with late potentials was mapped along the PN course.After obtaining another epicardial access,a second introducer sheath was placed,and a vascular balloon catheter was inserted into the epicardial space and inflated with saline solution to separate the PN from the epicardium.Once the absence of PN capture had been proven,radiofrequency was applied to aim for complete late potential elimination and avoid VT induction.CONCLUSION PN injury can occur as one of the complications following epicardial VT ablation procedures,and may prevent successful ablation of these arrhythmias.PN displacement by using large balloon catheters into the epicardial space seems to be feasible and reproducible,avoid procedure-related morbidity,and improve ablation success when performed in selected centers and by experienced operators.

Phrenic Nerve Injury Is a Differential Diagnosis of Hypoxemia after Video-Assisted Thoracoscopic Thymectomy:2 Cases Report and Literature Review

Hypoxemia after general anesthesia is not uncommon.For patients after thoracotomy,the differential diagnosis is usually difficult.Surgical,anesthetic,and patient-associated factors may contribute to postoperative hypoxemia.We described two patients who underwent videassisted thoracoscopic thymectomy and developed hypoxemia immediately after extubation.Phrenic nerve injury was suspected in both patients.One case recovered spontaneously without intervention.The second case who had been demonstrated as bilateral phrenic nerve injury after the operation was continuously on ventilator after physical therapy and respiratory training for 2 months.

Anatomical feasibility of vagus nerve esophageal branch transfer to the phrenic nerve

This study measured the vagus and phrenic nerves from 12 adult cadavers. We found that the width and thickness of the vagus and phrenic nerves were different in the chest. The distance from the point of the vagus nerve and phrenic nerve on the plane of the inferior border of portal pulmonary arteries （T point） was approximately 7 cm to the diaphragm and was approximately 10 cm to the clavicle level. The number of motor fibers in the vagus nerves was 1 716 ± 362, and the number of nerve fibers was 4 473 ± 653. The number of motor fibers in the phrenic nerves ranged from 3 078 ± 684 to 4 794 ± 638, and the number of nerve fibers ranged from 3 437 ± 642 to 5 071 ± 723. No significant difference was found in the total number of nerve fibers. The results suggest that width, thickness, and total number of nerve fibers are similar between the vagus and phrenic nerves, but the number of motor fibers is different between them.

Diaphragmatic Plication for Patients with Acute Phase Phrenic Nerve Paralysis Following Lung Transplantation: A Case Report

Phrenic nerve injury can occur as a complication of lung transplantation. A 54-year-old man underwent single-lung transplantation due to interstitial pneumonia. The patient required circulatory support with venoarterial extracorporeal membrane oxygenation and was unable to be weaned from ventilatory support with nitric oxide. Although enhanced CT scanning showed stenotic anastomosis of the right pulmonary artery (PA), pulmonary angiograph findings revealed that PA flow was normal under sedation and considerably decreased with spontaneous breathing. Fluoroscopy showed that the right diaphragm moved inversely to the position of the left diaphragm, indicating that the right phrenic nerve was paralytic. We performed diaphragmatic plication 7 days after lung transplantation and weaning from ventilator support was accomplished soon thereafter. Phrenic nerve dysfunction is an important clinical problem following lung transplantation. In the present case, diaphragmatic plication was effective for treatment of circulatory failure due to phrenic nerve paralysis even in acute phase after lung transplantation.

Phrenic and intercostal nerves with rhythmic discharge can promote early nerve regeneration after brachial plexus repair in rats

Exogenous discharge can positively promote nerve repair. We, therefore, hypothesized that endogenous discharges may have similar effects. The phrenic nerve and intercostal nerve, controlled by the respiratory center, can emit regular nerve impulses; therefore these endogenous automatically discharging nerves might promote nerve regeneration. Action potential discharge patterns were examined in the diaphragm, external intercostal and latissimus dorsi muscles of rats. The phrenic and intercostal nerves showed rhythmic clusters of discharge, which were consistent with breathing frequency. From the first to the third intercostal nerves, spontaneous discharge amplitude was gradually increased. There was no obvious rhythmic discharge in the thoracodorsal nerve. Four animal groups were performed in rats as the musculocutaneous nerve cut and repaired was bland control. The other three groups were followed by a side-to-side anastomosis with the phrenic nerve, intercostal nerve and thoracodorsal nerve. Compound muscle action potentials in the biceps muscle innervated by the musculocutaneous nerve were recorded with electrodes. The tetanic forces of ipsilateral and contralateral biceps muscles were detected by a force displacement transducer. Wet muscle weight recovery rate was measured and pathological changes were observed using hematoxylin-eosin staining. The number of nerve fibers was observed using toluidine blue staining and changes in nerve ultrastructure were observed using transmission electron microscopy. The compound muscle action potential amplitude was significantly higher at 1 month after surgery in phrenic and intercostal nerve groups compared with the thoracodorsal nerve and blank control groups. The recovery rate of tetanic tension and wet weight of the right biceps were significantly lower at 2 months after surgery in the phrenic nerve, intercostal nerve, and thoracodorsal nerve groups compared with the negative control group. The number of myelinated axons distal to the coaptation site of the musculocutaneous nerve at 1 month after surgery was significantly higher in phrenic and intercostal nerve groups than in thoracodorsal nerve and negative control groups. These results indicate that endogenous autonomic discharge from phrenic and intercostal nerves can promote nerve regeneration in early stages after brachial plexus injury.

Image features of two rare mediastinal tumors: schwannoma of intrathoracic phrenic nerve and clear cell chondrosarcoma of the rib

The current report focuses on two patients of the same age who presented similar appearances on initial anteroposterior chest images. Follow-up images showed superoanterior and superoposterior mediastinal lesions. The first patient with noninvasive cystic thymoma was suspected before surgery, while the pathologic diagnosis was intrathoracic phrenic nerve schwannoma. The second patient was with an asymmetric, dumbbell-shaped paravertebral tumor over T3 and T4 on the left side. The preoperative diagnostic images were interpreted as showing a neurogenic tumor. However, the pathologic report was cell chondrosarcoma.

Interest of thoracic ultrasound after cardiac surgery or interventional cardiology

Thoracic ultrasound has attracted much interest in detecting pleural effusion or pulmonary consolidation after cardiac surgery.In 2016,Trovato reported,in the World Journal of Cardiology,the interest of using,in addition to echocardiography,thoracic ultrasound.In this editorial,we highlight the value of assessing diaphragm function after cardiac surgery and interventional cardiology pro-cedures.Various factors are able to impair diaphragm function after such interventions.Diaphragm motion may be decreased by chest pain secondary to sternotomy,pleural effusion or impaired muscle function.Hemidiaphragmatic paralysis may be secondary to phrenic nerve damage complicating cardiac surgery or atrial fibrillation ablation.Diagnosis may be delayed.Indeed,respi-ratory troubles induced by diaphragm dysfunction are frequently attributed to pre-existing heart disease or pulmonary complications secondary to surgery.In addition,elevated hemidiaphragm secondary to diaphragm dysfunction is sometimes not observed on chest X-ray performed in supine position in the intensive care unit.Analysis of diaphragm function by ultrasound during the recovery period appears essential.Both hemidiaphragms can be studied by two complementary ultrasound methods.The mobility of each hemidiaphragms is measured by M-mode ultrasonography.In addition,recording the percentage of inspiratory thickening provides important information about the quality of muscle function.These two approaches make it possible to detect hemidiaphragm paralysis or dysfunction.Such a diagnosis is important because persistent diaphragm dysfunction after cardiac surgery has been shown to be associated with adverse respiratory outcome.Early respiratory physio-therapy is able to improve respiratory function through strengthening of the inspiratory muscles i.e.diaphragm and accessory inspiratory muscles.

Nerve transfer helps repair brachial plexus injury by increasing cerebral cortical plasticity

In the treatment of brachial plexus injury, nerves that are functionally less important are transferred onto the distal ends of damaged crucial nerves to help recover neuromuscular function in the target region. For example, intercostal nerves are transferred onto axillary nerves, and accessory nerves are transferred onto suprascapular nerves, the phrenic nerve is transferred onto the musculocutaneous nerves, and the contralateral C7 nerve is transferred onto the median or radial nerves. Nerve transfer has become a major method for reconstructing the brachial plexus after avulsion injury. Many experiments have shown that nerve transfers for treatment of brachial plexus injury can help reconstruct cerebral cortical function and increase cortical plasticity. In this review article, we summarize the recent progress in the use of diverse nerve transfer methods for the repair of brachial plexus injury, and we discuss the impact of nerve transfer on cerebral cortical plasticity after brachial plexus injury.

Evaluation of nerve transfer options for treating total brachial plexus avulsion injury： a retrospective study of 73 participants

Despite recent great progress in diagnosis and microsurgical repair, the prognosis in total brachial plexus-avulsion injury remains unfavorable.Insufficient number of donors and unreasonable use of donor nerves might be key factors. To identify an optimal treatment strategy for this condition, we conducted a retrospective review. Seventy-three patients with total brachial plexus avulsion injury were followed up for an average of 7.3 years. Our analysis demonstrated no significant difference in elbow-flexion recovery between phrenic nerve-transfer （25 cases）, phrenic nerve-graft （19 cases）, intercostal nerve （17 cases）, or contralateral C7-transfer （12 cases） groups. Restoration of shoulder function was attempted through anterior accessory nerve （27 cases）, posterior accessory nerve （10 cases）, intercostal nerve （5 cases）, or accessory ＋ intercostal nerve transfer （31 cases）. Accessory nerve ＋ intercostal nerve transfer was the most effective method. A significantly greater amount of elbow extension was observed in patients with intercostal nerve transfer （25 cases） than in those with contralateral C7 transfer （10 cases）. Recovery of median nerve function was noticeably better for those who received entire contralateral C7 transfer （33 cases） than for those who received partial contralateral C7 transfer （40 cases）. Wrist and finger extension were reconstructed by intercostal nerve transfer （31 cases）. Overall, the recommended surgical treatment for total brachial plexus-avulsion injury is phrenic nerve transfer for elbow flexion, accessory nerve ＋ intercostal nerve transfer for shoulder function, intercostal nerves transfer for elbow extension, entire contralateral C7 transfer for median nerve function, and intercostal nerve transfer for finger extension. The trial was registered at Clinical-Trials.gov （identifier： NCT03166033）.

A three-dimensional digital visualization model of cervical nerves in a healthy person

Three-dimensional reconstruction nerve models are classically obtained from two-dimensional images of ＂visible human＂ frozen sections. However, because of the flexibility of nerve tissues and small color differences compared with surrounding tissues, the integrity and validity of nerve tissues can be impaired during milling. Thus, in the present study, we obtained two-dimensional data from a healthy volunteer based on continuous CT angiography and magnetic resonance myelography. Semi-automatic segmentation and reconstruction were then conducted at different thresholds in different tissues using Mimics software. Small anatomical structures such as muscles and cervical nerves were reconstructed using the medical computer aided design module. Three-dimensional digital models of the cervical nerves and their surrounding structures were successfully developed, which allowed visualization of the spatial relation of anatomical structures with a strong three-dimensional effect, distinct appearance, clear distribution, and good continuity, precision, and integrality. These results indicate the validity of a three-dimensional digital visualization model of healthy human cervical nerves, which overcomes the disadvantages of milling, avoids data loss, and exhibits a realistic appearance and three-dimensional image.

Liposomal Bupivacaine in Erector Spinae Plane Block and Interscalene Block for Scapular and Proximal Humerus Resections

Erector spinae plane block (ESPB) is a novel fascial plane block that was first described in 2016. It is considered an alternative for brachial plexus blocks in shoulder surgeries as the erector spinae muscle extends to the cervical level. Herein, we present a successful multilevel ESPB plus an interscalene block using liposomal bupivacaine in a 45-year-old female patient with metastatic sarcoma who presented for scapula and proximal humerus resection. The post-operative course was smooth, and the patient was discharged home on post-operative day 2 with minimal narcotic requirements.

Diaphragmatic Plication: Retrospective Study with 54 Patients

Objective: This study seeks to evaluate the results of surgery performed according to the etiological causes of diaphragmatic eventration or paralysis. Method: Files of 54 patients (35 males, 19 females;mean age: 39.1 ± 3.01 years) who had undergone diaphragm plication between January 2005 and June 2011 in two clinics located in Istanbul were studied in terms of pulmonary spirometry, applied surgical procedure, duration of hospitalization, morbidity, and mortality. Results: In diaphragm plications, observed etiologies were isolated diaphragmatic eventration without phrenic nerve injury (Group 1) in 20 (37%) patients due to blunt thoracic trauma;Group 2 (thymoma in 19 (35.2%) patients;lung cancer in 7 (12.9%) patients;mediastinal tumor in 3 (5.6%) patients) and congenital heart surgery (Group 3) in 5 (9.3%) patients. The mean time to plication was 7.4 months in Group 1. The mean duration of hospitalization was 4 days in Group 1, 6.2 days in Group 2, 11.8 days in Group 3. Mean forced vital capacity, forced expiratory volume at 1 second improved by 17%, 20.3%, respectively (p In Group 1, mean dyspnea-related hospital admission before plication was 2.4 times. At the end of 6 months after plication mean dyspnea-related hospital admission was 0 time. All of them returned to daily activities or their job within 6 months in Group 1. Postoperative mortality was observed in 2 (3.7%) patients in Group 3 while the overall complication rates were 24%. The morbidity rates were 8%, 27.5%, 60%, respectively;and the mortality rates were 0%, 0%, 40%, respectively. Conclusion: As a result, it could be suggested that early and timely performed plications for diaphragmatic eventration improves functional status and assesses a shorter lenght of stay. On the other hand,simultaneously performed plications in intraoperative phrenic nerve resections can be performed with acceptable morbidity and no mortality. In diaphragmatic paralysis due to congenital heart surgery, morbidity and mortality rate is still high.

Improved C_(3-4) transfer for treatment of root avulsion of the brachial plexus upper trunk Animal experiments and clinical application

Experimental rats with root avulsion of the brachial plexus upper trunk were treated with the improved C34 transfer for neurotization of 05-6. Results showed that Terzis grooming test scores were significantly increased at 6 months after treatment, the latency of C5-6 motor evoked potential was gradually shortened, and the amplitude was gradually increased. The rate of C3 instead of C5 and the C4 ＋ phrenic nerve instead of C6 myelinated nerve fibers crossing through the anastomotic stoma was approximately 80%. Myelinated nerve fibers were arranged loosely but the thickness of the myelin sheath was similar to that of the healthy side. In clinical applications, 39 patients with root avulsion of the brachial plexus upper trunk were followed for 6 months to 4.5 years after treatment using the improved C3 instead of C5 nerve root transfer and C4 nerve root and phrenic nerve instead of C6 nerve root transfer. Results showed that the strength of the brachial biceps and deltoid muscles recovered to level IIHV, scapular muscle to level Ill-W, latissimus dorsi and pectoralis major muscles to above level Ⅲ, and the brachial triceps muscle to level 0 Ill. Results showed that the improved 03-4 transfer for root avulsion of the brachial plexus upper trunk in animal models is similar to clinical findings and that C3-4 and the phrenic nerve transfer for neurotization of C5-6 can innervate the avulsed brachial plexus upper trunk and promote the recovery of nerve function in the upper extremity.

EFFECTS OF MANGANESE ON NEUROMUSCULAR JUNCTION TRANSMISSION

The effects of manganese on neuromuscular junction transmission were studied in the isolated rat phrenic nerve diaphragm preparation, chick biventer cervicis nerve-muscle preparation and toad rectus abdominis muscle preparation. It wa found that manganese could adversely andconcentration-dependently inhibit muscular contraction response developed by indirect stimulation or direct stimulation. The IC50 of indirect and direct stimulation were 0.28 mmol/L and 10 mmol/Lrespectively. The time required to inhibit 50% of the contraction by indirect stimulation was 4.3±1. 0 min. The inhibitory action could be antagonized partially by high Ca2+. Manganese could reduce the seusitivity of the chick biventer cervicis muscle to acetylcholine, and shift the dose-respond curves foracetylcholine to the right in a nonparallel manner with a pD2' value of 2. 62. The result suggested that manganese acted on pre- and post-synaptic sites.