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.

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.

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.

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.

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.

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.

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.

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.

Phrenic nerve end-to-side neurotization in treating brachial plexus avulsion: an experimental study in rats.

The aim of this study was to extend the clinical application of phrenic nerve neurotization in treating brachial plexus avulsion injury, reducing the possible damage on the diaphragm function. Fifty-one male Sprague-Dawley rats and 9 transgenic rats were used in this study. Evaluations including behavioral observation, histology, and electrophysiology study were performed postoperatively. The functional recovery of rats with the end-to-side neurorrhaphy reached 80% of those with end-to-end neurorrhaphy, and the function of diaphragm was preserved. The fluorescence study revealed abundant collateral sprouting of the phrenic nerve axons through the coaptation site in all the experimental groups. The study showed that the end-to-side neurorrhaphy in a helicoid manner and the standard end-to-side neurorrhaphy were effective in the treatment of brachial plexus root avulsion injury with little harm to the function of diaphragm. This will extend the clinical application of phrenic nerve neurotization in treating brachial plexus avulsion injury.

Helicoid end-to-side and oblique attachment technique in repair of the musculocutaneous nerve injury with the phrenic nerve as a donor: an experimental study in rats.

The purpose of this study was to identify if a modified end-to-side repair can achieve equal results of nerve regeneration compared to an end-to-end repair using donor phrenic nerves in repair of the musculocutaneous nerve and also pulmonary protection. Eighteen rats were divided into three groups of six each comparing two nerve graft techniques: helicoid end-to-side plus distal oblique repair vs. traditional end-to-end repair, using a donor phrenic nerve. The saphenous nerve was used as a graft between the phrenic nerve and the musculocutaneous nerve. The third group was used as control; the musculocutaneous nerve was transected without any repair. Three months postoperatively, electrophysiology, tetanic force, moist muscle weight, histology, nerve fiber counting, and chest X-ray were evaluated. All results have shown that this modified end-to-side repair was superior to the end-to-end repair. The former did not compromise the diaphragm function, but the latter showed an elevation of the diaphragm. Little recovery was seen in the third group. The conclusion is that this modified end-to-side repair can replace the traditional end-to-end repair using donor phrenic nerves with better results of nerve regeneration without diaphragm compromise.

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.

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.

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.

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.

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.

Restoration of diaphragmatic function after diaphragm reinnervation by inferior laryngeal nerve; experimental study in rabbits.

OBJECTIVES: To assess the possibilities of reinnervation in a paralyzed hemidiaphragm via an anastomosis between phrenic nerve and inferior laryngeal nerve in rabbits. Reinnervation of a paralyzed diaphragm could be an alternative to treat patients with ventilatory insufficiency due to upper cervical spine injuries. MATERIAL AND METHOD: Rabbits were divided into five groups of seven rabbits each. Groups I and II were respectively the healthy and the denervated control groups. The 3 other groups were all reinnervated using three different surgical procedures. In groups III and IV, phrenic nerve was respectively anastomosed with the abductor branch of the inferior laryngeal nerve and with the trunk of the inferior laryngeal nerve. In group V, the fifth and fourth cervical roots were respectively anastomosed with the abductor branch of the inferior laryngeal nerve and with the nerve of the sternothyroid muscle (originating from the hypoglossal nerve). Animals were evaluated 4 months later using electromyography, transdiaphragmatic pressure measurements, sonomicrometry and histological examination. RESULTS: A poor inspiratory activity was found in quiet breathing in the reinnervated groups, with an increasing pattern of activity during effort. In the reinnervated groups, transdiaphragmatic pressure measurements and sonomicrometry were higher in group III with no significant difference with groups IV and V. CONCLUSION: Inspiratory contractility of an hemidiaphragm could be restored with immediate anastomosis after phrenic nerve section between phrenic nerve and inferior laryngeal nerve.

[Long-term impact of transfer of phrenic nerve on respiratory system of children: a clinical study of 34 cases].

OBJECTIVE: To study the long-term impact of transfer of phrenic nerve on respiratory system of children. METHODS: Thirty-four children with brachial plexus injury, 25 boys and 9 girls, underwent transfer of phrenic nerve and were divided into 3 groups according to the age when they underwent operation: group of the age of 0 - 12 months (n = 17), group of 13 - 36 months (n = 11), and group of 37 - 60 months (n = 6). Thirty-four sex, height, and body weight-matched healthy children were used as controls. Follow-up, including physical examination, pulmonary function examination (tidal volume, ventilation, etc), blood gas analysis, and chest radiography, was conducted for 4.03 years (3 - 7 years). RESULTS: The values of maximum vital capacity of the group of 0 - 12 months and group of 13 - 36 months were 1.0 L +/- 0.2 L and 1.2 L +/- 0.4 L, both significantly lower than those of the corresponding control groups (1.3 L +/- 0.3 L and 1.4 L +/- 0.5 L, both P < 0.05). The values of one-second vital capacity of the group of 0 - 12 months and group of 13 - 36 months were 0.8 L +/- 0.1 L and 0.9 L +/- 0.1 L, both significantly lower than those of the corresponding control groups (1.0 L +/- 0.1 L and 1.0 L +/- 0.1 L, both P < 0.05). However, the values of the maximum vital capacity and one-second vital capacity of the group of 37 - 60 months were 1.6 L +/- 0.3 L and 1.8 L +/- 0.5 L respectively, both not significantly different from those of the controls (both P > 0.05). The results of blood gas analysis of the 3 operation groups were not significantly different from those of the corresponding controls. Chest radiograph showed that the diaphragm top was raised by 1.93 intercostal spaces (0.5 - 3.5 intercostal spaces) in comparison with the contralateral sides with significant differences between the group of 0 - 12 months and the group of 13 - 36 months and between the group of 0 - 12 months and the group of 37 - 60 months (both P < 0.05). The recurrent respiratory infection rate and of the groups of 0 - 12 months and 13 - 36 months were 47.1% and 27.3% respectively, both significantly higher than that of the group of 37 - 60 months (0%). The thorax deformity rate of the groups of 0 - 12 months and 13 - 36 months were 41.2% and 9.1% respectively, both significantly higher than that of the group of 37 - 60 months (0%). Three of the children in the group of 0 - 12 months (17.6%) had digestive system symptoms. CONCLUSION: Transfer of phrenic nerve operated on children younger than 3 years may cause abnormalities of respiratory system, thorax, and digestive system. The younger the patients the more severe the consequences of the operation. The children older than 3 years tolerate the operation better.

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.