Transfer of the phrenic nerve to musculocutaneous nerve via sural nerve graft after total brachial plexus injury

A middle age male presented a right total brachial plexus injury after motorcycle fall one year ago. Subsequent electromyographic evaluation was consistent with C5, C6, C7, C8 and T1 root avulsion. The patient was submitted to a right transfer of the phrenic nerve to musculocutaneous nerve , using rural nerve graft.

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.

Pulmonary and Biceps Function after Intercostal and Phrenic Nerve Transfer for Brachial Plexus Injuries

This pseudo-randomized study was performed to compare the pulmonary function and biceps recovery after intercostal (19 cases) and phrenic (17 cases) nerve transfer to the musculocutaneous nerve for brachial plexus injury patients with nerve root avulsions. Pulmonary function was assessed pre-operatively and postoperatively by measuring the forced vital capacity, forced expiratory volume in 1 second, vital capacity, and tidal volume. Motor recovery of biceps was serially recorded. Our results revealed that pulmonary function in the phrenic nerve transfer group was still significantly reduced 1 year after surgery. In the intercostal nerve transfer group, pulmonary function was normal after 3 months. Motor recovery of biceps in the intercostal nerve group was significantly earlier than that in phrenic nerve group.

We conclude that pulmonary and biceps functions are better after intercostal nerve transfer than after phrenic nerve transfer in the short term at least.

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.

[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.

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.

Ventilation and Exercise Performance After Phrenic Nerve and Multiple Intercostal Nerve Transfers for Avulsed Brachial Plexus Injury

BACKGROUND

Diaphragmatic excursion, lung function, exercise performance, and clinical symptoms have not been previously described in patients after phrenic nerve transfer (PNT) and/or multiple intercostal nerve transfer (MIT) for the repair of avulsed brachial plexus injury (ABPI) to prevent functional musculoskeletal impairment in the shoulder.

SETTING

A university-based hospital.

METHODS

Dyspnea scores, chest ultrasonography to assess diaphragmatic excursion, and pulmonary function testing were performed to assess ventilation in patients sustaining trauma to their brachial plexus. In addition, cardiopulmonary exercise testing was also performed. These studies were obtained prior to surgical intervention, and were repeated postoperatively at 6, 12, 18, 24, and 36 months. The results obtained preoperatively were compared to those obtained throughout the postoperative monitoring period.

RESULTS

This study demonstrates that the PNT-MIT procedure results in permanent ipsilateral diaphragmatic paralysis accompanied by an approximately 8% decrease in inspiratory capacity, FVC, and total lung capacity. There was also an 11% increase in diffusing capacity noted during the period between 6 months and 3 years after PNT-MIT procedure. Despite these measurable changes in lung function, the patients reported amelioration of their dyspnea complaint within 6 months of undergoing this procedure, which was due mainly to an improvement in their cardiovascular exercise performance related to increased daily activity.

CONCLUSIONS

This study demonstrates that the PNT-MIT procedure is a safe method for the restoration of drop shoulder incurred by ABPI. This surgery has an impact on measurable diaphragmatic and lung function but with minimal impact in terms of postoperative clinical symptoms and exercise performance.

Repair of brachial plexus lesions by end-to-side side-to-side grafting neurorrhaphy: experience based on 11 cases

Eleven brachial plexus lesions were repaired using end-to-side side-to-side grafting neurorrhaphy in root ruptures, in phrenic and spinal accessory nerve neurotizations, in contralateral C7 neurotization, and in neurotization using intact interplexus roots or cords. The main aim was to approximate donor and recipient nerves and promote regeneration through them. Another indication was to augment the recipient nerve, when it had been neurotized or grafted to donors of dubious integrity, when it was not completely denervated, when it had been neurotized to a nerve with a suboptimal number of fibers, when it had been neurotized to distant donors delaying its regeneration, and when it had been neurotized to a donor supplying many recipients. In interplexus neurotization, the main indication was to preserve the integrity of the interplexus donors, as they were not sacrificeable. The principles of end-to-side neurorrhaphy were followed. The epineurium was removed. Axonal sprouting was induced by longitudinally slitting and partially transecting the donor and recipient nerves, by increasing the contact area between both of them and the nerve grafts, and by embedding the grafts into the split predegenerated injured nerve segments. Agonistic donors were used for root ruptures and for phrenic and spinal accessory neurotization, but not for contralateral C7 or interplexus neurotization. Single-donor single-recipient neurotization was successfully followed in phrenic neurotization of the suprascapular (3 cases) and axillary (1 case) nerves, spinal accessory neurotization of the suprascapular nerve (1 case), and dorsal part of contralateral C7 neurotization of the axillary nerve (2 cases). Apart from this, recipient augmentation necessitated many donor to single-recipient neurotizations. This was successfully performed using phrenic-interplexus root to suprascapular transfers (2 cases), phrenic-contralateral C7 to suprascapular transfer (1 case), and spinal accessory-interplexus root to musculocutaneous transfer (1 case). Both recipient augmentation and increasing the contact area between grafts and recipients necessitated single or multiple donor to many recipient neurotizations. This was applied in root ruptures (3 cases), with results comparable to those obtained in classical nerve-grafting techniques. It was also applied in ventral C7 transfer to the lateral or medial cords (3 cases) with functional recovery occurring in the biceps and pronator teres muscles, but not in dorsal C7 transfer to the axillary and radial nerves (3 cases) with functional recovery occurring in the deltoid and triceps muscles, and in whole C7 transfer to C5, 6, 7, 8T1 roots with functional recovery occurring in the deltoid (M4), biceps (M4), pronator teres (M4), and triceps (M3) (3 cases), and less so in the flexor carpi ulnaris and FDP (M3) (1 case) and the extensor digitorum longus (M3) (1 case). Contralateral C7 transfer to the lateral and posterior cords (4 cases) was followed by cocontractions that took 1 year to improve and that involved the rotator cuff, deltoid, biceps, and pronator teres (all agonists). Functional recovery in the triceps muscle was less than in the above muscles. Contralateral C7 transfer to C5-7 (1 case) was followed by cocontractions that took 1 year to resolve and that occurred between the deltoid, biceps, and flexor digitorum profundus. Interplexus root neurotization was done only in conjunction with other neurotization techniques, and so its role is difficult to judge. Though the same applies to regenerated lateral cord transfer to the posterior cord (2 cases), the successful results obtained from medial cord neurotization to the axillary, musculocutaneous, and radial nerves (1 case), and from ulnar and median nerve neurotization to the radial nerve (1 case), show that neurotization at the interplexus cord level may play a role in brachial plexus regeneration and may even be used to neurotize nerves and muscles distal to the elbow. The timing of repair was within 6 months after injury, except for 2 cases. In the first case, contralateral C7 transfer was successfully performed more than 1 year after injury. The second case was an obstetric palsy operated upon at age 8. Deterioration in motor power of the donor muscles that improved in 6 months was observed in 2 cases of interplexus neurotization at the cord level, because of looping the sural nerve grafts tightly around the donor nerves. Deterioration in donor-muscle motor power as a consequence of end-to-side neurorrhaphy was noted in the obstetric palsy case, when the flexor carpi radialis (donor) became grade 3 instead of grade 4. This was associated with cocontractions between it and the extensors. It took nearly 1 year to improve.

Selective neurotization of the median nerve in the arm to treat brachial plexus palsy. Surgical technique

BACKGROUND

The current method for treatment of median nerve palsy after a brachial plexus injury is unpredictable. On the basis of an anatomic study of the median nerve in the arm, we present a new method of selective neurotization of the median nerve.

METHODS

Internal topographic features of the fascicular groups of the median nerve were observed in seventeen cadavera. On the basis of the anatomical results, selective neurotization of the posterior fascicular group of the median nerve in the arm was performed in one patient with a complete brachial plexus palsy.

RESULTS

In the distal half of the arm, the branches of the median nerve consistently collect into three fascicular groups, which are located at the anterior, middle, and posterior parts of the median nerve trunk. The anterior fascicular group is composed of the branches to the pronator teres and the flexor carpi radialis, the posterior fascicular group is composed mainly of the anterior interosseous nerve and the branches to the palmaris longus, and the middle fascicular group is made up mostly of the branches to the hand and the flexor digitorum superficialis. A transfer of the full length of the phrenic nerve was used to selectively reinnervate the posterior fascicular group of the median nerve in a patient with a complete brachial plexus palsy. The muscles supplied by the posterior fascicular group regained Grade-4 power, according to the system of the Medical Research Council, sixteen months after surgery.

CONCLUSIONS

The typical arrangement of the fascicular groups of the median nerve in the arm favors the technique of selective neurotization, which has been used effectively in one patient to date.

Comparative clinic study on vascularized and nonvascularized full-length phrenic nerve transfer

In order to understand whether the vascularizing procedure has any clinical value in nerve transfer and grafting, we compared nonvascularized and vascularized full-length phrenic never transfers in patients with a brachial plexus injury. Full-length phrenic nerve transfer to the musculocutaneous nerve had been conducted by the technique of video-assisted thoracic surgery in 15 patients. Three kinds of procedures were carried out. The first involved retaining the initial point of the phrenic nerve and dissecting the full-length distal nerve. The second involved keeping the cervical segment and isolating the thoracic segment of the phrenic nerve. The last involved vascularized phrenic nerve transfer. All these phrenic nerves were sutured to musculocutaneous nerves. After 28-35 months, the results of electrophysiology and function of the biceps brachii muscle were compared. All three procedures had no significant differences and led to the same functional recovery of the biceps brachii muscle after at least 28 months of follow-up. In conclusion, the vascularizing procedure had little clinical value, not only in full-length phrenic nerve transfer, but also in nerve grafting irrespective of the length of the gap, when the recipient bed had normal vascularity.

Laryngeal reinnervation

Laryngeal reinnervation refers to any of a number of surgical procedures intended to restore neural connections to the larynx, which have usually been lost from some type of trauma (eg, surgical). The nerve function(s) to be restored may be those of the recurrent laryngeal nerve or its subdivisions, those of the superior laryngeal nerve, or both, and they may be motor or sensory. Several different donor nerves are available and have been described. The technique used may be direct end-to-end anastomosis (neurorrhaphy), direct implantation of a nerve ending into a muscle, the nerve-muscle pedicle technique, or muscle-nerve-muscle methods. These nerves and techniques may be combined in many ways. A number of new techniques have been reported in animal studies; however, the animal studies do not always predict the results of analogous surgeries in human patients. The historical and current perspectives on these techniques are discussed in this article.

Selective neurotization of the median nerve in the arm to treat brachial plexus palsy. An anatomic study and case report

BACKGROUND

The current method for treatment of median nerve palsy after a brachial plexus injury is unpredictable. On the basis of an anatomic study of the median nerve in the arm, we present a new method of selective neurotization of the median nerve.

METHODS

Internal topographic features of the fascicular groups of the median nerve were observed in seventeen cadavera. On the basis of the anatomical results, selective neurotization of the posterior fascicular group of the median nerve in the arm was performed in one patient with a complete brachial plexus palsy.

RESULTS

In the distal half of the arm, the branches of the median nerve consistently collect into three fascicular groups, which are located at the anterior, middle, and posterior parts of the median nerve trunk. The anterior fascicular group is composed of the branches to the pronator teres and the flexor carpi radialis, the posterior fascicular group is composed mainly of the anterior interosseous nerve and the branches to the palmaris longus, and the middle fascicular group is made up mostly of the branches to the hand and the flexor digitorum superficialis. A transfer of the full length of the phrenic nerve was used to selectively reinnervate the posterior fascicular group of the median nerve in a patient with a complete brachial plexus palsy. The muscles supplied by the posterior fascicular group regained Grade-4 power, according to the system of the Medical Research Council, sixteen months after surgery.

CONCLUSIONS AND CLINICAL RELEVANCE

The typical arrangement of the fascicular groups of the median nerve in the arm favors the technique of selective neurotization, which has been used effectively in one patient to date.

Phrenic nerve transfer in the treatment of brachial plexus avulsion: An experimental study of nerve regeneration and muscle morphology in rats

The regeneration of motor and sensory neurons and the morphological changes of the target muscle after phrenic nerve transfer were investigated in adult rats. Six months following nerve transfer, 326.0 +/- 16.31 phrenic motoneurons regenerated into musculocutaneous nerve, which is not different from the normal number of phrenic motoneurons. The regenerated motoneurons exhibited a 14% nonsignificant hypertrophy. Of the dorsal root ganglia (DRG) neurons, 255.8 +/- 45.26 regenerated, which was significantly lower than the number of normal phrenic DRG neurons. The regenerated phrenic DRG neurons showed a 24% close-to-significant atrophy. The target muscle fiber morphology changed considerably after reinnervation. The present results suggest that the phrenic nerve has very good regenerative ability in terms of its motoneurons and a relatively insufficient sensory neuronal regeneration.

Full-length phrenic nerve transfer by means of video-assisted thoracic surgery in treating brachial plexus avulsion injury

Phrenic nerve transfer has been widely used in treating brachial plexus avulsion injury. However, the present method crosses the thoracic part of the phrenic nerve, and nerve graft is needed, resulting in a long period of regeneration and partly irreversible muscle atrophy. We present our early experience of using video-assisted thoracic surgery to harvest a full length of phrenic nerve for transfer. Fifteen patients (mean age, 28 years) were treated. The thoracic part of the phrenic nerve was freed by means of video-assisted thoracic surgery and taken out of the thoracic cavity, and a full-length phrenic nerve was transferred to the musculocutaneous nerve to recover elbow flexion. The patients were followed. Another 29 patients with long-term follow-up who underwent traditional cervical phrenic nerve to musculocutaneous nerve transfer in our institute between 1994 and 1997 were selected. The period of newborn potential appearing in the biceps and the period for biceps to achieve M3 between two groups were compared. The operation was safe and no complications occurred. The additional length of phrenic nerve was 12.3 +/- 4.5 cm. Eleven patients received sufficient follow-up. Eight patients achieved biceps recovery to M3 (elbow flexion against gravity), and mean time was 198.8 +/- 36.0 days, much earlier than that of the traditional method (p < 0.01). Pulmonary function recovered to the preoperative level 9 months after operation. This new method is safe and minimally invasive. The result of full-length phrenic nerve transfer is much better than that of the traditional method. It obviously shortens the time required for nerve reinnervation, and offers a promising method for patients who have had a long interval from injury to operation and for forearm muscle reconstruction by phrenic nerve transferred to the median nerve or combined with free-muscle transfer.

Brachial plexus neurotization with donor phrenic nerves and its effect on pulmonary function

OBJECT

To examine possible side effects of neurotizations in which the phrenic nerve was used, pulmonary function was analyzed pre- and postoperatively in patients with brachial plexus injury and root avulsions.

METHODS

Twenty-three patients with complete brachial plexus palsy underwent neurotization of the musculocutaneous nerve, with the phrenic nerve as donor material. Patients who suffered lung contusions as part of the primary injury were excluded from this study. In 12 patients (five left-sided and seven right-sided neurotizations) pre- and postoperative functional parameters were compared and additional body plethysmography was performed more than 12 months postsurgery. Of the 23, no patient experienced pulmonary problems postoperatively. Nonetheless, pulmonary functional parameters showed a vital capacity in percent of the predicted value of 9.8 +/- 6.3% (mean +/- standard deviation [SD]) in all patients examined, which was a significant reduction (p = 0.0002). In right-sided phrenic nerve transfers this reduction was significant, at 14.3 +/- 3.3% (mean +/- SD), whereas left-sided transfers showed a nonsignificant reduction of 3.6 +/- 3.5% (mean +/- SD). The observed decrease in vital capacity (VC) correlates with the maximal inspiratory pressure (Pi(max)) as an indication of clinical significance.

CONCLUSIONS

When the right phrenic nerve is used as a donor in neurotization of the musculocutaneous nerve, the patient incurs a higher risk of reduced pulmonary VC. If possible, the left phrenic nerve should be preferred. The Pi(max) has to be determined preoperatively to avoid any further decrease in the already reduced pulmonary function due to the initial injury.

Restoration of elbow flexion after brachial plexus injury: the role of nerve and muscle transfers

Brachial plexus trauma results in a variable loss of upper extremity function. The restoration of this function requires elbow flexion of adequate strength and range of motion. A proper evaluation of brachial plexus lesions is a prerequisite to any reconstructive procedure, and appropriate guidelines are presented. One option for restoring elbow flexion is a nerve transfer. The best results with this procedure are obtained in young patients treated within 6 months of injury. Another option is a free or pedicled muscle transfer, which should be considered in older patients or patients treated more than 6 months after an injury. Muscle transfers may also be used to augment the results of nerve transfer procedures. Choices and clinical results of donor nerves and muscle for transfer are discussed, and an algorithm for treatment is presented.

Experimental reinnervation of a strap muscle with a few roots of the phrenic nerve in rabbits

In order to compare application of the roots of the phrenic nerve to the ansa hypoglossi for laryngeal muscle neurotization, 1 or more roots from the phrenic nerve were implanted into the right sternothyroid (RST) muscle of rabbits (n = 36). Controls were intact animals (in which RST innervation is provided by the ansa; n = 6) and denervated ones (n = 6). At 66 +/- 2 days (mean +/- SE) after neurotization, during quiet breathing, inspiratory electromyographic activity and isometric contraction force were observed in all reinnervated RST muscles (n = 24). During maximal inspiratory effort, electromyographic activity and force increased. In animals reinnervated by the C4 root alone, forces (46.22 +/- 7.8 g) were significantly higher than in intact animals (10.83 +/- 5.0 g). Retrograde labeling proved the phrenic origin of the neurotization. Electromyography of the diaphragm was recorded. We conclude that in rabbits, neurotization of a strap muscle by 1 or 2 roots of the phrenic nerve allows inspiratory contraction, even during quiet breathing. Such inspiratory activity is not observed in sternothyroid muscles of intact animals innervated by the ansa hypoglossi.

[Experimental study on delayed reinnervation of laryngeal adductor and abductor]

To investigate time of delayed reinnervated laryngeal muscle, 15 dogs were divided into two groups. The right recurrent laryngeal nerves of 10 dogs in experimental group were cut, and repaired at 4, 6, 8, 10 and 12 months intervals by transposition of the phrenic nerve to the recurrent laryngeal nerve after cutting and suturing the adductor branch to the main branch of ansa cervicalis. The right recurrent laryngeal nerves of 5 dogs in control group were cut, but did not repair. Laryngoscope, electromyography, contractile tension of laryngeal muscle and histologic studies were performed at six months postoperatively. The results showed that fair recovery of adduction and abduction was noted within ten months interval, and the effect of adduction was better than that of abduction. The effect decreased gradually with the denervated time increased. The conclusion demonstrated that delayed reinnervation of laryngeal muscle should be performed within ten months.

Laryngeal abductor reinnervation with a phrenic nerve transfer after a 9-month delay

BACKGROUND

Successful restoration of laryngeal abductor function, using the phrenic nerve, has been described in the cat model in the acute phase. However, in clinical practice there is usually a considerable delay between injury to the RLN and presentation for treatment. Delayed reinnervation therefore would be more suitable in clinical practice.

OBJECTIVE

To test the feasibility of delayed selective abductor reinnervation following transection of the recurrent laryngeal nerve (RLN).

MATERIALS AND METHODS

In 12 cats, the right RLN was severed. Nine months later, the phrenic nerve was anastomosed to the distal RLN stump with all its branches directed toward the posterior cricoarytenoid muscle. For 10 weeks after the reconstruction, electromyography and videolaryngoscopy were performed weekly. Finally, histological analysis of the RLN was performed.

RESULTS

Evaluation was possible in 11 cats. Reinnervation of the right posterior cricoarytenoid muscle with the phrenic nerve occurred in 10 cats following nerve anastomosis, but results of videolaryngoscopy showed adequate to good abduction in only 4 cats. The main limiting factor was reduced mobility of the cricoarytenoid joint. Evidence of spontaneous subclinical reinnervation after the delay was observed in 7 cats but apparently did not impede the surgical reinnervation.

CONCLUSIONS

Delayed selective laryngeal abductor reinnervation was feasible, but function recovery was less successful than if performed immediately. Future investigations should concentrate on early determinants of spontaneous restoration of function to allow early selection of patients who are eligible for reinnervation surgery.

Phrenic nerve transfer in the repair of brachial plexus injuries: an animal model

Ten young mongrel dogs underwent unilateral denervation of the brachial plexus. In six dogs, a 2-cm segment of phrenic nerve autograft was sutured to either the resected musculocutaneous nerve or the radial nerve. A hemoclip was applied to either musculocutaneous or radial nerve in the control groups. Five months postoperatively, the grafted musculocutaneous nerve demonstrated less fibrous tissue and less muscle atrophy of the biceps when compared to the control group with clipped nerve. In the group with the grafted radial nerve, the electromyographic findings of multiphasic action potential and muscle contraction from electric stimulation suggested reinnervation of the radial nerve.

IN CONCLUSION

phrenic nerve transfer may be used to repair specific damages to nerve trunk with histological, electromyographic and clinical recovery.

Use of the phrenic nerve for brachial plexus reconstruction

To examine the clinical effectiveness and safety of phrenic nerve neurotization for brachial plexus reconstruction, the authors retrospectively analyzed the surgically treated cases within the period between August 1970 and March 1990. There was a total of 180 patients who sustained brachial plexus injuries and had phrenic nerve transfer. The phrenic nerve was identified and traced distally to give the longest possible length and sectioned. The proximal stump was coapted to the distal segment of the musculocutaneous nerve, either directly or through a nerve graft. Sixty-five patients who were seen in followup for >2 years were studied. The time taken for the return of a muscle power rating of 3 (M3) in the biceps muscle ranged from 3 to 30 months; the average time was 9.5 months. Of the patients, 84.6% regained biceps power to M3 and greater strength. Only 1 patient had a transient respiratory problem after surgery. Pulmonary function tests showed decreased pulmonary capacities within 1 year of operation, improving toward 2 years. Thus, it is concluded that phrenic nerve neurotization can be accepted as a sound option for the restoration of biceps function in brachial plexus injury.

Surgical technique and application of pericardial fat pad and pericardiophrenic grafts

Oncologic developments in stage IIIA lung cancer and complex tracheal reconstruction have renewed interest in bronchial stump and tracheal coverage. The surgical techniques to mobilize and apply pericardial fat pad and pericardiophrenic grafts are discussed.

Nerve transfer for treatment of root avulsion of the brachial plexus: experimental studies in a rat model

In order to evaluate the effects of various nerve transfers, experimental rat models simulating root avulsions of the brachial plexus were created, using four different types of nerve transfers. Four groups of 160 rats were randomly divided, and phrenic nerves, double intercostal nerves, accessory nerves, and single intercostal nerves were transferred. Electrophysiologic and histologic examinations and functional evaluations were performed at different postoperative intervals. Phrenic nerve transfer was found to be superior to the other types most likely on the basis of superior neural regeneration. A single phrenectomy in the rat was found to have no apparent effect on pulmonary function.

Phrenic nerve transfer for treatment of root avulsion of the brachial plexus

Phrenic nerve transfer was performed in 164 patients with root avulsion of the brachial plexus. The methods of operation consisted of phrenic nerve transfer to and anastomosis with the musculocutaneous nerve, the phrenic nerve bridging to the musculocutaneous nerve, phrenic nerve anastomosis with or bridging to the median nerve, and phrenic nerve anastomosis with other nerves. Follow-up of 65 patients for more than 2 years showed an effective rate of 84.6%. The result indicated that this operation has no deleterious effects on respiration, and the surgical effects are related to severity of injury, duration, mode of operation and patient's age.

[Phrenic nerve transfer treating root avulsion of the brachial plexus]

164 patients with injury of root avulsion of the brachial plexus was treated by way of ipsilateral phrenic nerve transfer through a time period from 1970 to 1987. The among 65 cases that had been followed up for 2-13.5 years on average, 55 cases (84.6%) regained muscular strength of 30 or more. None of the patients had any subjective feeling or objective signs of respiratory disturbance, although post- operative machinery tests and laboratory surveys had detected some impairment of pulmonary function, which gradually improved with lapse of time. In conclusion age of the patients, length of the time delayed for surgery, severity of the nerve injury and the operative choice are the determining factors of the final results.

Phrenic nerve transfer for brachial plexus motor neurotization

We report a series of 164 patients who underwent phrenic neurotization to elements of the brachial plexus with root avulsion injuries. Recipient nerves included musculocutaneous nerve in 125 patients (78 direct neurotizations and 48 with intervening autograft), median nerve in 10 patients, and a variety of other nerves in 28 patients. Sixty-five patients presented a follow-up period of 2 or more years. Of this group, 55 patients (84.6%) achieved a recovery of M-3 or better. We observed no long-term deleterious effects on respiratory function.

Selective reinnervation of vocal cord adductors in unilateral vocal cord paralysis

Laryngeal reinnervation procedures were performed in a series of dogs. An attempt was made to reinnervate the vocal cord adductors with one nerve graft, while a different nerve was grafted to the abductors. The recurrent laryngeal nerve was dissected distally to its terminal branches, where the abductor-adductor sorting out occurs. The abductor branch was reinnervated with a phrenic nerve graft as previously described. The adductor division was grafted with one of the following nerves: proximal recurrent laryngeal, external branch of superior laryngeal, or ansa hypoglossi. Results revealed that in most cases it was indeed possible to reinnervate the adductive and abductive vocal cord muscles separately. Recurrent laryngeal nerve anastomosis to the distal adductor division produced strong reinnervation, but appeared to inhibit in some way the phrenic reinnervation of the abductor branch. Ansa hypoglossi anastomosis to the adductor division seemed to induce satisfactory reinnervation of the adductor musculature with the least noticeable donor deficit.

Phrenic nerve graft for bilateral vocal cord paralysis

For bilateral vocal cord paralysis, the phrenic nerve graft procedure has been used in five patients. Data from four of these patients suggest that the technique may in some way improve the glottic airway without long-term diaphragmatic paralysis. No patient to date has demonstrated visible inspiratory vocal cord abduction however. The mechanism of action, if any, is unclear at this time, and we have no electromyographic nor other physiologic data to confirm that true posterior cricoarytenoid muscle reinnervation has taken place.

Laryngeal reinnervation using the split-phrenic nerve-graft procedure

A new operative procedure for reinnervation of the paralyzed larynx is described. Initial successes in a series of animals have shown that use of the split-phrenic nerve-graft procedure results in functional abduction of the paralyzed vocal cord, while preserving innervation to the diaphragm. Electromyography, microlaryngoscopic movies, chest fluoroscopic examination, and nerve compound action potential recordings were all used to document these findings. This procedure appears to have several advantages over the neuromuscular pedicle operation described by Tucker.

Laryngeal transplantation: current status 1974

There are four major areas of concern that must be examined before human laryngeal transplantation can be considered feasible in clinical practice. These are: 1. surgical mechanics of revascularization; 2. reinnervation; 3. prevention of host rejection; and 4. justification. Of these criteria, the first two habe been met sucessfully at present. Safe suppression of rejection without increased risk of cancer recurrence remains to be achieved. Until this third criterion is satisfied, one is probably not justified to make further attempts at laryngeal transplantation in humans.