Video-assisted thoracoscopic surgery (VATS) aided full-length phrenic nerve transfer for restoration of elbow flexion.

BACKGROUND: In complete brachial plexus injury, phrenic nerve (PN) is frequently used in neurotization for elbow flexion restoration. The advancement in video-assisted thoracoscopic surgery (VATS) allows full-length PN dissection intrathoracically for direct coaptation to recipient without nerve graft. PURPOSE: We report our experience in improving the surgical technique and its outcome. METHODS: Seven patients underwent PN dissection via VATS and full-length transfer to musculocutaneous nerve (MCN) or motor branch of biceps (MBB) from June 2015 to June 2018. Comparisons were made with similar group of patients who underwent conventional PN transfer. RESULTS: Mean age of patients was 21.9 years. All were males involved in motorcycle accidents who sustained complete brachial plexus injury. We found the elbow flexion recovery were earlier in full-length PN transfer. However, there was no statistically significant difference in elbow flexion strength at 3 years post-surgery. CONCLUSION: We propose full-length PN transfer for restoration of elbow flexion in patients with delayed presentation.

Intercostal nerve transfer for restoration of the diaphragm muscle function after phrenic nerve transfer in total brachial plexus avulsion.

OBJECT: To determine the possibility of innervation of the diaphragm muscle using intercostal nerve after ipsilateral phrenic nerve transfer in total brachial plexus avulsion. METHODS: Bilateral phrenic nerves and the 9th intercostal nerves were observed inside the thorax. The point where the phrenic nerve entered the diaphragm muscle (point A), the point where the 9th intercostal nerve gave rise to the cutaneous branch (point B) and crossed the posterior axillary line (point C) and the point where the posterior axillary line met the insertion of the diaphragm muscle (point D) were identified. The distances between points B and C, points A and C and from points A through D to C were recorded respectively. The 9th intercostal nerve was transferred to the distal stump of the phrenic nerve in one patient after phrenic nerve transfer to avulsed brachial plexus. RESULTS: The mean distances between points B and C, points A and C and from points A through D to C were 12.20 ± 1.04 cm, 10.32 ± 1.02 cm and 16.43 ± 0.91 cm on the right side respectively, 11.78 ± 1.21 cm, 7.77 ± 0.85 cm and 11.74 ± 1.00 cm on the left side respectively. The 9th intercostal nerve was used to innervate the distal stump of the phrenic nerve in one patient after the phrenic nerve transfer to the avulsed brachial plexus. The diaphragm muscle function partially recovered one year after the operation. CONCLUSION: The 9th intercostal nerve can be transferred to the distal stump of the phrenic nerve to restore the diaphragm muscle function according to the anatomical study. The movement of the diaphragm muscle was partially restored in one clinical case.

Comparison of neuropathic pain characteristics associated with total brachial plexus injury before and after surgical repair: A retrospective study.

OBJECTIVES: The goal of this study was to compare clinical characteristics of neuropathic pain associated with total brachial plexus injury before and after surgeries and to correlate possible contributing factors concerning to the pain prognosis. PATIENTS AND METHODS: Thirty patients with both total brachial plexus injury and neuropathic pain were included. Neuropathic pain was evaluated in terms of pain intensities, symptoms and regions. Pain intensities were evaluated by a visual analogue scale. The Neuropathic Pain Symptoms Inventory questionnaire and body maps were used to compare the pain symptoms and regions. Demographic data, injury and repair information were evaluated to analyze the possible factors influencing the prognosis. RESULTS: The average pain score of all participants was 7.13 ± 2.46 preoperatively and 5.40 ± 2.08 postoperatively. All patients were divided into Pain Relief Group and Pain Aggravation Group. Older age (p = 0.042), machine traction injury (p = 0.019)and nerve transplantation(p = 0.015) seemed to be related with pain aggravation. Paroxysmal pain was aggravated after surgical repairs (p = 0.041), while paresthesia/dysesthesia improved after surgery (p = 0.003). The permanent component of the pain (spontaneous pain) did not show any significant change (p = 0.584). Pain in C5 (p < 0.001) and C6 (p = 0.031) dermatomes got relieved after surgery. CONCLUSION: This study revealed the neuropathic pain of most patients with total brachial plexus injury was alleviated after neurosurgery, and the pain prognosis of different symptoms and regions varied after the nerve repair.

Experimental Study of Nerve Transfer to Restore Diaphragm Function.

BACKGROUND: Diaphragmatic paralysis after phrenic nerve injury is an infrequent but serious condition. The destruction of respiratory function after unilateral phrenic nerve injury has been the subject of many investigations. METHODS: In this study, we used a rat model of complete paralysis of the unilateral diaphragm to observe changes in pulmonary function. RESULTS: We found in young rats with complete paralysis of the unilateral diaphragm, the vital capacity and total lung capacity show compensation after 4 weeks, and contralateral phrenic nerve transfer can enhance pulmonary function. However, in the aged rats, respiratory function parameters do not show compensation until 16 weeks after injury. CONCLUSIONS: These findings suggest that contralateral phrenic nerve end-to-side anastomosis is a promising therapeutic strategy. In general, our results suggest that this surgical method may hold great potential to be a secure, feasible, and effective technique to rescue diaphragmatic function.

Immediate selective laryngeal reinnervation in vagal paraganglioma patients.

OBJECTIVE: This prospective case series aimed to present the outcomes of immediate selective laryngeal reinnervation. METHODS: Two middle-aged women with vagal paraganglioma undergoing an excision operation underwent immediate selective laryngeal reinnervation using the phrenic nerve and ansa cervicalis as the donor nerve. Multidimensional outcome measures were employed pre-operatively, and at 1, 6 and 12 months post-operatively. RESULTS: The voice handicap index-10 score improved from 23 (patient 1) and 18 (patient 2) at 1 month post-operation, to 5 (patient 1) and 1 (patient 2) at 12 months. The Eating Assessment Tool 10 score improved from 20 (patient 1) and 24 (patient 2) at 1 month post-operation, to 3 (patient 1) and 1 (patient 2) at 12 months. There was slight vocal fold abduction observed in patient one and no obvious abduction in patient two. CONCLUSION: Selective reinnervation is safe to perform following vagal paraganglioma excision conducted on the same side. Voice and swallowing improvements were demonstrated, but no significant vocal fold abduction was achieved.

The phrenic nerve transfer in the treatment of a septuagenarian with brachial plexus avulsion injury: a case report.

Phrenic nerve transfer has been a well-established procedure for restoring elbow flexion function in patients with brachial plexus avulsion injury. Concerning about probably detrimental respiratory effects brought by the operation, however, stirred up quite a bit of controversy. We present a case report of the successful application of phrenic nerve as donor to reinnervate the biceps in a septuagenarian with brachial plexus avulsion injury, not accompanied with significant clinical respiratory problem.

Cortical Reorganization in Dual Innervation by Single Peripheral Nerve.

BACKGROUND: Functional recovery after peripheral nerve injury and repair is related with cortical reorganization. However, the mechanism of innervating dual targets by 1 donor nerve is largely unknown. OBJECTIVE: To investigate the cortical reorganization when the phrenic nerve simultaneously innervates the diaphragm and biceps. METHODS: Total brachial plexus (C5-T1) injury rats were repaired by phrenic nerve-musculocutaneous nerve transfer with end-to-side (n = 15) or end-to-end (n = 15) neurorrhaphy. Brachial plexus avulsion (n = 5) and sham surgery (n = 5) rats were included for control. Behavioral observation, electromyography, and histologic studies were used for confirming peripheral nerve reinnervation. Cortical representations of the diaphragm and reinnervated biceps were studied by intracortical microstimulation techniques before and at months 0.5, 3, 5, 7, and 10 after surgery. RESULTS: At month 0.5 after complete brachial plexus injury, the motor representation of the injured forelimb disappeared. The diaphragm representation was preserved in the "end-to-side" group but absent in the "end-to-end" group. Rhythmic contraction of biceps appeared in "end-to-end" and "end-to-side" groups, and the biceps representation reappeared in the original biceps and diaphragm areas at months 3 and 5. At month 10, it was completely located in the original biceps area in the "end-to-end" group. Part of the biceps representation remained in the original diaphragm area in the "end-to-side" group. Destroying the contralateral motor cortex did not eliminate respiration-related contraction of biceps. CONCLUSION: The brain tends to resume biceps representation from the original diaphragm area to the original biceps area following phrenic nerve transfer. The original diaphragm area partly preserves reinnervated biceps representation after end-to-side transfer.

Phrenic Nerve Transfer for Reconstruction of Elbow Extension in Severe Brachial Plexus Injuries.

Background Restoring elbow extension is an important objective to pursue when repairing the brachial plexus in patients with a flail arm. Based upon the good results obtained using the phrenic nerve to restore elbow flexion and shoulder stability, we hypothesized that this nerve could also be employed to reconstruct elbow extension in patients with severe brachial plexus injuries. Methods A retrospective study of 10 patients in which the phrenic nerve targeted the radial nerve (7 patients) or the branch to the long head of the triceps (3 patients) as a surgical strategy for reconstruction of the brachial plexus. Results The mean postoperative follow-up time was 34 months. At final follow-up, elbow extension graded as M4 was measured in three patients, Medical Research Council MRC M3 in five patients, and M2 in one patient, while one patient experienced no measurable recovery (M0). No patient complained or demonstrated any signs of respiratory insufficiency postoperatively. Conclusions The phrenic nerve is a reliable donor for reanimation of elbow extension in such cases, and the branch to the long head of the triceps should be considered as a better target for the nerve transfer.

Direct Coaptation of the Phrenic Nerve With the Posterior Division of the Lower Trunk to Restore Finger and Elbow Extension Function in Patients With Total Brachial Plexus Injuries.

BACKGROUND: To overcome the mismatch in nerve sizes in phrenic nerve transfer to the radial nerve for elbow and finger extension reanimation for patients with total brachial plexus injuries (TBPI), a selective neurotization procedure was designed. OBJECTIVE: To investigate the long-term results of phrenic nerve transfer to the posterior division of the lower trunk with direct coaptation in restoring elbow and finger extension after TBPI. METHODS: Phrenic nerve was transferred to and directly coapted with the posterior division of the lower trunk in 27 patients with TBPI. Seven patients were <18 years old (adolescent group), and the remaining 20 patients ≥18 years (adult group). RESULTS: Postoperative mean follow-up period was 54 ± 9 months (range, 48-85 months). The motor function attained M3 or greater in 81.5% of patients for elbow extension and in 48% of patients for finger extension. The percentage of patients who regained M3 or greater muscle power of finger extension in the adolescent group and the adult group was 71.4%, and 40%, respectively. Meanwhile, 85.7% in the adolescent group and 80% in the adult group achieved M3 or greater muscle power of elbow extension. There were no significant differences between the 2 groups. The elbow extension and finger extension were synchronous contractions and did not become independent of respiratory effort. CONCLUSION: This procedure simultaneously and effectively restores the function of elbow and finger extension in patients after TBPI. However, the patients could not do elbow and finger extension separately.

The phrenic nerve as a donor for brachial plexus injuries: is it safe and effective? Case series and literature analysis.

BACKGROUND: Controversy exists surrounding the use of the phrenic nerve for transfer in severe brachial plexus injuries. The objectives of this study are: (1) to present the experience of the authors using the phrenic nerve in a single institution; and (2) to thoroughly review the existing literature to date. METHODS: Adult patients with C5-D1 and C5-C8 lesions and a phrenic nerve transfer were retrospectively included. Patients with follow-up shorter than 18 months were excluded. The MRC muscle strength grading system was used to rate the outcome. Clinical repercussions relating to sectioning of the phrenic nerve were studied. An intense rehabilitation program was started after surgery, and compliance to this program was monitored using a previously described scale. Statistical analysis was performed with the obtained data. RESULTS: Fifty-one patients were included. The mean time between trauma and surgery was 5.7 months. Three-quarters of the patients had C5-D1, with the remainder C5-C8. Mean post-operative follow-up was 32.5 months A MRC of M4 was achieved in 62.7% patients, M3 21.6%, M2 in 3.9%, and M1 in 11.8%. The only significant differences between the two groups were in graft length (9.8 vs. 15.1 cm, p = 0.01); and in the rehabilitation compliance score (2.86 vs. 2.00, p = 0.01). CONCLUSIONS: Results of phrenic nerve transfer are predictable and good, especially if the grafts are short and the rehabilitation is adequate. It may adversely affect respiratory function tests, but this rarely correlates clinically. Contraindications to the use of the phrenic nerve exist and should be respected.

Comparative study of phrenic and intercostal nerve transfers for elbow flexion after global brachial plexus injury.

BACKGROUND: Global brachial plexus injuries (BPIs) are devastating events frequently resulting in severe functional impairment. The widely used nerve transfer sources for elbow flexion in patients with global BPIs include intercostal and phrenic nerves. OBJECTIVE: The aim of this study was to compare phrenic and intercostal nerve transfers for elbow flexion after global BPI. METHODS: A retrospective review of 33 patients treated with phrenic and intercostal nerve transfer for elbow flexion in posttraumatic global root avulsion BPI was carried out. In the phrenic nerve transfer group, the phrenic nerve was transferred to the anterolateral bundle of the anterior division of the upper trunk (23 patients); in the intercostal nerve transfer group, three intercostal nerves were coapted to the anterolateral bundles of the musculocutaneous nerve. The British Medical Research Council (MRC) grading system, angle of elbow flexion, and electromyography (EMG) were used to evaluate the recovery of elbow flexion at least 3 years postoperatively. RESULTS: The efficiency of motor function in the phrenic nerve transfer group was 83%, while it was 70% in the intercostal nerve transfer group. The two groups were not statistically different in terms of the MRC grade (p=0.646) and EMG results (p=0.646). The outstanding rates of angle of elbow flexion were 48% and 40% in the phrenic and intercostal nerve transfer groups, respectively. There was no significant difference of outstanding rates in the angle of elbow flexion between the two groups. CONCLUSION: Phrenic nerve transfer had a higher proportion of good prognosis for elbow flexion than intercostal nerve transfer, but the effective and outstanding rate had no significant difference for biceps reinnervation between the two groups according to MRC grading, angle of elbow flexion, and EMG.

End-to-side neurotization with different donor nerves for treating brachial plexus injury: an experimental study in a rat model.

INTRODUCTION: End-to-side neurotization is currently used to treat brachial plexus injury, but it is not clear which donor nerve yields the best outcome. We performed experiments to determine the optimal donor nerve. METHODS: A total of 66 male Sprague-Dawley rats were assigned to 1 of 3 groups. Group A was the control group. In Group B, the phrenic nerve was used as the donor, while the ipsilateral C7 nerve root served as the donor in Group C. The epineurial window was used in end-to-side neurorrhaphy. Behavioral observations, histology, electrophysiology, and fluorescence retrotracing were performed postoperatively. RESULTS: Fluorescence retrotracing confirmed nerve regeneration in both Groups B and C upon end-to-side neurotization. The outcome of Group B was superior to that of Group C. CONCLUSIONS: Use of the phrenic nerve as the donor nerve yielded a better outcome than use of the ipsilateral C7 nerve root.

Comparative study of phrenic nerve transfers with and without nerve graft for elbow flexion after global brachial plexus injury.

BACKGROUND: Nerve transfer is a valuable surgical technique in peripheral nerve reconstruction, especially in brachial plexus injuries. Phrenic nerve transfer for elbow flexion was proved to be one of the optimal procedures in the treatment of brachial plexus injuries in the study of Gu et al. OBJECTIVE: The aim of this study was to compare phrenic nerve transfers with and without nerve graft for elbow flexion after brachial plexus injury. METHODS: A retrospective review of 33 patients treated with phrenic nerve transfer for elbow flexion in posttraumatic global root avulsion brachial plexus injury was carried out. All the 33 patients were confirmed to have global root avulsion brachial plexus injury by preoperative and intraoperative electromyography (EMG), physical examination and especially by intraoperative exploration. There were two types of phrenic nerve transfers: type1 - the phrenic nerve to anterolateral bundle of anterior division of upper trunk (14 patients); type 2 - the phrenic nerve via nerve graft to anterolateral bundle of musculocutaneous nerve (19 patients). Motor function and EMG evaluation were performed at least 3 years after surgery. RESULTS: The efficiency of motor function in type 1 was 86%, while it was 84% in type 2. The two groups were not statistically different in terms of Medical Research Council (MRC) grade (p=1.000) and EMG results (p=1.000). There were seven patients with more than 4 month's delay of surgery, among whom only three patients regained biceps power to M3 strength or above (43%). A total of 26 patients had reconstruction done within 4 months, among whom 25 patients recovered to M3 strength or above (96%). There was a statistically significant difference of motor function between the delay of surgery within 4 months and more than 4 months (p=0.008). CONCLUSION: Phrenic nerve transfers with and without nerve graft for elbow flexion after brachial plexus injury had no significant difference for biceps reinnervation according to MRC grading and EMG. A delay of the surgery after the 4 months might imply a bad prognosis for the recovery of the function.

Outcome after transfer of intercostal nerves to the nerve of triceps long head in 25 adult patients with total brachial plexus root avulsion injury.

OBJECT: The intercostal nerves (ICNs) have been used to repair the triceps branch in some organizations in the world, but the reported results differ significantly. The effect of this procedure requires evaluation. Thus, this study aimed to evaluate the outcome of ICN transfer to the nerve of the long head of the triceps muscle and to determine the factors affecting the outcome of this procedure. METHODS: A retrospective review was conducted in 25 patients with global root avulsion brachial plexus injuries who underwent ICN transfer. The nerves of the long head of the triceps were the recipient nerves in all patients. The ICNs were used in 2 different ways: 2 ICNs were used as donor nerves in 18 patients, and 3 ICNs were used in 7 patients. The mean follow-up period was 5.6 years. RESULTS: The effective rate of motor recovery in the 25 patients was 56% for the function of the long head of the triceps. There was no significant difference in functional recovery between the patients with 2 or 3 ICN transfers. The outcome of this procedure was not altered if combined with phrenic nerve transfer to the biceps branch. Patients in whom surgery was delayed 6 months or less achieved better results. CONCLUSIONS: The transfer of ICNs to the nerve of long head of the triceps is an effective procedure for treating global brachial plexus avulsion injuries, even if combined with phrenic nerve transfer to the biceps branch. Two ICNs appear to be sufficient for donation. The earlier the surgery is performed, the better are the results achieved.

Nerve transfers for the upper extremity: new horizons in nerve reconstruction.

Nerve transfers are key components of the surgeon's armamentarium in brachial plexus and complex nerve reconstruction. Advantages of nerve transfers are that nerve regeneration distances are shortened, pure motor or sensory nerve fascicles can be selected as donors, and nerve grafts are generally not required. Similar to the principle of tendon transfers, expendable donor nerves are transferred to denervated nerves with the goal of functional recovery. Transfers may be subdivided into intraplexal, extraplexal, and distal types; each has a unique role in the reconstructive process. A thorough diagnostic workup and intraoperative assessment help guide the surgeon in their use. Nerve transfers have made a positive impact on the outcomes of nerve surgery and are essential tools in complex nerve reconstruction.

Long-term observation of respiratory function after unilateral phrenic nerve and multiple intercostal nerve transfer for avulsed brachial plexus injury.

BACKGROUND: Phrenic nerve transfer (PNT) or multiple intercostal nerve transfer (MIT) alone are reported to have no significant impact on pulmonary function in the short or medium term, but it has rarely been reported whether the combination of PNT-MIT could influence respiratory function in the long term. OBJECTIVE: Respiratory function was evaluated after PNT and PNT-MIT 7 to 19 years (mean, 10 years) postoperatively. METHODS: Twenty-three adult patients with brachial plexus avulsion injuries who underwent PNT-MIT were compared with 19 corresponding patients who underwent PNT. Pulmonary function testings, phrenic nerve conduction study, and chest fluoroscopy were performed. In the PNT-MIT group, further investigation was performed on the effect of the number of transferred intercostal nerves and the timing of MIT. RESULTS: In the PNT-MIT group, forced vital capacity, forced expiratory volume in one second, and total lung capacity were 73.69%, 72.04%, and 74.81% of predicted values without significant differences from the PNT group. Diaphragmatic paralysis permanently existed with 1 to 1.5 intercostal spaces (ICSs) elevation and near 1 ICS reduced excursion. There was no statistical difference between the PNT and PNT-MIT groups. Furthermore, 3 and 4 intercostal nerves transferred resulted in no further decrease in pulmonary function test results than 2 intercostal nerves. No significant difference was found when PNT and MIT were performed at the same stage or with an interval. CONCLUSION: PNT-MIT did not result in additional impairment in respiratory function in adult patients compared with PNT alone. It is safe to transfer 2 to 4 intercostal nerves at 1 to 2 months delay after PNT.

Full-length phrenic nerve transfer as the treatment for brachial plexus avulsion injury to restore wrist and finger extension.

INTRODUCTION: The functional restoration of wrist and finger extension after complete brachial plexus avulsion injury remains an unsolved problem. We conducted a prospective study to elucidate a new method for resolving this injury. METHODS: Six patients with complete brachial plexus avulsion injury underwent a new surgical procedure in which the full-length phrenic nerve was transferred to the medial portion of the radial nerve at the level of the latissimus dorsi insertion via endoscopic thoracic surgery. RESULTS: In 5 patients, extensor carpi ulnaris and extensor carpi radialis strength recovered to Medical Research Council grade ≥M3, and in 4 patients extensor digitorum strength recovered to ≥M3. CONCLUSIONS: Neurotization of phrenic nerve to the medial portion of the radial nerve at the level of latissimus dorsi insertion is a feasible means of restoring wrist and finger extension in cases of complete brachial plexus avulsion injury.

Functional regeneration of respiratory pathways after spinal cord injury.

Spinal cord injuries often occur at the cervical level above the phrenic motor pools, which innervate the diaphragm. The effects of impaired breathing are a leading cause of death from spinal cord injuries, underscoring the importance of developing strategies to restore respiratory activity. Here we show that, after cervical spinal cord injury, the expression of chondroitin sulphate proteoglycans (CSPGs) associated with the perineuronal net (PNN) is upregulated around the phrenic motor neurons. Digestion of these potently inhibitory extracellular matrix molecules with chondroitinase ABC (denoted ChABC) could, by itself, promote the plasticity of tracts that were spared and restore limited activity to the paralysed diaphragm. However, when combined with a peripheral nerve autograft, ChABC treatment resulted in lengthy regeneration of serotonin-containing axons and other bulbospinal fibres and remarkable recovery of diaphragmatic function. After recovery and initial transection of the graft bridge, there was an unusual, overall increase in tonic electromyographic activity of the diaphragm, suggesting that considerable remodelling of the spinal cord circuitry occurs after regeneration. This increase was followed by complete elimination of the restored activity, proving that regeneration is crucial for the return of function. Overall, these experiments present a way to markedly restore the function of a single muscle after debilitating trauma to the central nervous system, through both promoting the plasticity of spared tracts and regenerating essential pathways.