Selective Transfer of the C7 Nerve Root: An Experimental Study

Posterior division of ipsilateral C7 transfer to C5 for shoulder abduction limitation

Background

Reparation of C5 by proximal selective ipsilateral C7 transfer has been reported for the treatment of neurogenic shoulder abduction limitation as an alternative to the reparation of the suprascapular nerve (SSN) and the axillary nerve (AXN) by distal nerve transfers. However, there is a lack of evidence to support either strategy leading to better outcomes based on long-term follow-up.

Objective

The purpose of the study was to investigate the safety and long-term outcomes of the posterior division of ipsilateral C7 (PDIC7) transfer to C5 in treating neurogenic shoulder abduction limitation.

Methods

A total of 27 cases with limited shoulder abduction caused by C5 injury (24 cases of trauma, 2 cases of neuritis, and 1 case of iatrogenic injury) underwent PDIC7 transfer to the C5 root. A total of 12 cases (11 cases of trauma and 1 case of neuritis) of C5 injury underwent spinal accessory nerve (SAN) transfer to SSN plus the triceps muscular branch of the radial nerve (TMBRN) transfer to AXN. The patients were followed up for at least 12 months for muscle strength and shoulder abduction range of motion (ROM).

Results

In cases that underwent PDIC7 transfer, the average shoulder abduction was 105.9° at the 12-month follow-up. In total, 26 of 27 patients recovered at least M3 (13 reached M4) (Medical Research Council Grading) of the deltoid. In cases that underwent SAN transfer to SSN plus TMBRN to AXN, the average shoulder abduction was 84.6° at the 12-month follow-up. In total, 11 of 12 patients recovered at least M3 (4 reached M4) of the deltoid.

Conclusion

Posterior division of ipsilateral C7 transfer is a one-stage, safe, and effective surgical procedure for patients with neurogenic shoulder abduction limitation.

Contralateral C7 nerve transfer in the treatment of upper-extremity paralysis: a review of anatomical basis, surgical approaches, and neurobiological mechanisms

The previous three decades have witnessed a prosperity of contralateral C7 nerve (CC7) transfer in the treatment of upper-extremity paralysis induced by both brachial plexus avulsion injury and central hemiplegia. From the initial subcutaneous route to the pre-spinal route and the newly-established post-spinal route, this surgical operation underwent a series of innovations and refinements, with the aim of shortening the regeneration distance and even achieving direct neurorrhaphy. Apart from surgical efforts for better peripheral nerve regeneration, brain involvement in functional improvements after CC7 transfer also stimulated scientific interest. This review summarizes recent advances of CC7 transfer in the treatment of upper-extremity paralysis of both peripheral and central causes, which covers the neuroanatomical basis, the evolution of surgical approach, and central mechanisms. In addition, motor cortex stimulation is discussed as a viable rehabilitation treatment in boosting functional recovery after CC7 transfer. This knowledge will be beneficial towards improving clinical effects of CC7 transfer.

Direct Repair of the Lower Trunk to Residual Nerve Roots for Restoration of Finger Flexion After Total Brachial Plexus Injury

PURPOSE

Residual nerve root stumps have been used to neurotize the median nerve in an attempt to restore finger flexion function in patients suffering from total brachial plexus injury. However, the results have been unsatisfactory mainly because of the need to use a long nerve graft. The authors have tried to improve the quality of restored finger flexion by direct approximation of available (ruptured) ipsilateral root stumps to the lower trunk (LT). We sought to validate these results using objective outcome measures.

METHODS

This is a study of 27 cases of total posttraumatic brachial plexus palsies. In each case, the neck was explored and ruptured root stumps identified. The LT was mobilized by separating it from the posterior division and the medial cutaneous nerve of the forearm distally. The mobilized LT was then approximated directly to an ipsilateral root stump. The arm was immobilized against the trunk for 2 months. The patients were observed for return of function in the paralyzed upper limb. The presence and strength of finger flexion was measured using the British Medical Council grading.

RESULTS

The follow-up period was 36 to 74 months (average, 56.9 ± 13.7 months). Recovery of active finger flexion was M4 in 10 patients, M3 in 8 patients, and M2 to M0 in 9 patients. Meaningful recovery (M3 or greater) of finger flexion was achieved in 18 of 27 patients.

CONCLUSIONS

The results of active finger flexion can be improved by direct approximation of the LT to an ipsilateral root stump.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

Contralateral C7 transfer via both ulnar nerve and medial antebrachial cutaneous nerve to repair total brachial plexus avulsion: a preliminary report

Aim: After brachial plexus injuries, sacrifice of the contralateral C7 (cC7) root from the non-injured side is well tolerated and various schemes to innervate the injured side from the cC7 root have been used. Objective: To demonstrate the surgical outcomes from transferring the cC7 to the affected side via both the ulnar nerve and medial antebrachial cutaneous nerve (MACN).Methods: A retrospective study of 16 adult patients sustaining total brachial plexus avulsion who underwent this procedure. The British Medical Research Council (MRC) grading system and the disabilities of the arm, shoulder, and hand (DASH) questionnaire scoring were used to evaluate the recovery.Results: About 68.75% of the patients achieved functional recovery of elbow flexion to M3 or better and 43.75% achieved motor recovery of wrist and finger flexion to M3 or better. Sensation in the median nerve territory recovered to S2 or better in 68.75%. The DASH scores after surgery were significantly lower than those before surgery.Conclusions: cC7 transfer via both ulnar and MACNs is an effective and safe procedure in patients sustaining total injuries of brachial plexus.

Restoration of ulnar nerve motor function by pronator quadratus motor branch: an anatomical study

BACKGROUND

The traditional surgical approach to repair of brachial plexus lesions involves use of whole segment ulnar nerve graft for contralateral seventh cervical (cC7) nerve root transfer, which sabotages the possibility of ulnar nerve recovery. We assessed the anatomical feasibility of a new approach that involves preservation of the motor branch of ulnar nerve (MBUN), for a later stage repair using the recovered pronator quadratus motor branch (PQMB), subsequent to the cC7 transfer procedure.

METHODS

Twenty-seven adult cadaver arms and one side of fresh adult cadaver were used in this study. The anterior interosseous nerve and its PQMB, as well as the motor and sensory branches of the ulnar nerve were dissected. The distances from the end of PQMB to the mid-point of a line joining the radial styloid and ulnar styloid, as well as to the point of divergence of the ulnar nerve, were measured. The MBUN was dissected from distal to proximal and the maximum length was measured. The diameter and number of axons of the nerve branches were also recorded.

RESULTS

The distance from the end of the PQMB to the midpoint of the radial styloid and ulnar styloid was 6.04 ± 0.52 cm, and that to the point of divergence of the ulnar nerve was 8.02 ± 0.63 cm. The maximum length of the MBUN after its dissociation was 9.70 ± 1.38 cm. The mean diameters of axons of the MBUN and PQMB were 0.09 ± 0.02 cm and 0.05 ± 0.01 cm, respectively. The corresponding mean numbers of axons were 2913 ± 624 and 757 ± 183, respectively.

CONCLUSIONS

The results indicate that the PQMB is suitable for transferring to the MBUN without nerve graft. This anatomical study paves the way for further testing of this new procedure after cC7 transfer in clinical settings.

Effect of Collateral Sprouting on Donor Nerve Function After Nerve Coaptation: A Study of the Brachial Plexus

Background

The aim of the present study was to evaluate the donor nerve from the C7 spinal nerve of the rabbit brachial plexus after a coaptation procedure. Assessment was performed of avulsion of the C5 and C6 spinal nerves treated by coaptation of these nerves to the C7 spinal nerve.

Material/Methods

After nerve injury, fourteen rabbits were treated by end-to-side coaptation (ETS), and fourteen animals were treated by side-to-side coaptation (STS) on the right brachial plexus. Electrophysiological and histomorphometric analyses and the skin pinch test were used to evaluate the outcomes.

Results

There was no statistically significant difference in the G-ratio proximal and distal to the coaptation in the ETS group, but the differences in the axon, myelin sheath and fiber diameters were statistically significant. The comparison of the ETS and STS groups distal to the coaptation with the controls demonstrated statistically significant differences in the fiber, axon, and myelin sheath diameters. With respect to the G-ratio, the ETS group exhibited no significant differences relative to the control, whereas the G-ratio in the STS group and the controls differed significantly. In the electrophysiological study, the ETS and STS groups exhibited major changes in the biceps and subscapularis muscles.

Conclusions

The coaptation procedure affects the histological structure of the nerve donor, but it does not translate into changes in nerve conduction or the sensory function of the limb. The donor nerve lesion in the ETS group is transient and has minimal clinical relevance.

Transdiscal C6-C7 contralateral C7 nerve root transfer in the surgical repair of brachial plexus avulsion injuries

BACKGROUND

Repair of complete brachial plexus avulsion injuries may require contralateral C7 nerve root transfer. The available techniques might allow direct neuroraphy in about 50 % of cases but the others require interposing nerve grafts or humeral shaft shortening. We aimed to see if transdiscal C6-C7 contralateral C7 nerve root transfer is technically feasible and if it allows direct coaptation with the contralateral nerve roots in 100 % of cases.

METHODS

In ten fresh-frozen adult cadavers, the C7 nerve root was sectioned just before it connects with other brachial plexus branches and re-routed though the C6-C7 disc space to the contralateral side. A complete C6-C7 discectomy was performed and the disc space kept open with the aid of an autologous iliac crest bone graft.

RESULTS

Transdiscal C6-C7 contralateral C7 nerve root transfer is technically feasible. In our cadavers, it provided 5.3 ± 1.2 SDcm of extra length that allowed direct coaptation with the contralateral nerve roots, mainly C8 and T1.

CONCLUSIONS

Transdiscal C6-C7 contralateral C7 nerve root transfer is technically feasible. In our dissections it lengthens the available C7 nerve root stump by 5.3 ± 1.2SDcm. The increase was 4 cm versus the retropharyngeal route making direct coaptation with the contralateral C8 and T1 nerve roots possible.

Contralateral C7 nerve transfer with direct coaptation to restore lower trunk function after traumatic brachial plexus avulsion

BACKGROUND

Contralateral C7 nerve transfer to the median nerve has been used in an attempt to restore finger flexion in patients with total brachial plexus avulsion injury. However, the results have not been satisfactory mainly because of the requirement to use a long bridging nerve graft, which causes an extended nerve regeneration process and irreversible muscle atrophy. A new procedure involving contralateral C7 nerve transfer via a modified prespinal route and direct coaptation with the injured lower trunk is presented here.

METHODS

Contralateral C7 nerve transfer via the modified prespinal route and direct coaptation with the injured lower trunk was performed in seventy-five patients with total brachial plexus avulsion injury. Thirty-five required humeral shortening osteotomy (3 to 4.5 cm) in order to accomplish the direct coaptation. The contralateral C7 nerve was also transferred to the musculocutaneous nerve through the bridging medial antebrachial cutaneous nerve arising from the lower trunk in forty-seven of the seventy-five patients. Recovery of finger, wrist, and elbow flexion was evaluated with use of the modified British Medical Research Council muscle grading system.

RESULTS

The mean follow-up period (and standard deviation) was 57 ± 6 months (range, forty-eight to seventy-eight months). Motor function with a grade of M3+ or greater was attained in 60% of the patients for elbow flexion, 64% of the patients for finger flexion, 53% of the patients for thumb flexion, and 72% of the patients for wrist flexion.

CONCLUSIONS

Contralateral C7 nerve transfer via a modified prespinal route and direct coaptation with the injured lower trunk decreases the distance for nerve regeneration in patients with total brachial plexus avulsion injury. There was satisfactory recovery of finger flexion and wrist flexion in this series. In addition, contralateral C7 nerve transfer was successfully used to repair two different target nerves: the lower trunk and the musculocutaneous nerve.

Contralateral C7 nerve transfer - Our experiences over past 25 years

Contralateral C7 nerve transfer has been used in treating brachial plexus avulsion injury since 1986. During the past two and half decades, much has been achieved, yet more needs to be explored. In this review article, the indications, technical details, outcome and pitfalls of this technique are summarized.

Partial Ipsilateral C7 Transfer to the Upper Trunk for C5-C6 Avulsion of the Brachial Plexus

BACKGROUND:

Ipsilateral whole C7 root transfer has been reported in treating C5-C6 avulsion. To minimize donor deficits, partial ipsilateral C7 (PIC7) transfer was developed.

OBJECTIVE:

To investigate the long-term results of PIC7 transfer to the upper trunk in treating C5-C6 avulsion of the brachial plexus.

METHODS:

We prospectively studied 8 young adults with C5-C6 avulsion. Five patients (group A) who also had spinal accessory nerve (SAN) injury underwent PIC7 transfer to the upper trunk. The other 3 patients (group B) without SAN injury underwent a combination of PIC7 to the upper trunk and the SAN to the suprascapular nerve (SSN). Postsurgical evaluations including donor deficits, functional recovery, and co-contraction of the muscles were performed 1 week later and then at intervals of 3 months.

RESULTS:

After a mean period of 39.2 months, all subjects were found to have gained elbow flexion of 110 to 150° with muscle strength of M4-5. The patients in group B achieved external rotation of 60 to 70° at M3-4, and 2 achieved shoulder abductions approaching 180° at M4. The patients in group A showed no active external rotation and shoulder abduction of 25 to 50° at M2-3. The temporary deficits caused by PIC7 transfer disappeared in all subjects within the first 3 months. Co-contraction of the latissimus dorsi against the deltoid was recorded in group A but not in group B.

CONCLUSION:

PIC7 transfer, when combined with SAN transfer to SSN as a novel approach, is a safe, easy, and efficacious surgical procedure for patients with simple C5-C6 avulsion.

Contralateral C7 nerve root transfer to neurotize the upper trunk via a modified prespinal route in repair of brachial plexus avulsion injury

PURPOSE

In this report, we present our experience on the repair of brachial plexus root avulsion injuries with the use of contralateral C7 nerve root transfers with nerve grafting through a modified prespinal route.

METHODS

The outcomes of the contralateral C7 nerve root transfer to neurotize the upper trunk and C5/C6 nerve roots of the total or near total brachial plexus nerve root avulsion injury in a series of 41 patients were evaluated. The contralateral C7 nerve root that was dissected to the distal end of the divisions, along with the sural nerve graft, were placed underneath the anterior scalene and longus colli muscles, and then passed through the retro-esophageal space to neurotize the recipient nerve. The mean length of the dissected contralateral C7 nerve root was 6.5 ± 0.7 cm, and the mean length of sural nerve graft was 6.8 ± 1.9 cm. The suprascapular nerve was neurotized additionally by the phrenic nerve or the terminal motor branch of accessory nerve in some patients.

RESULTS

The mean length of the follow-up was 47.2 ± 14.5 months. The muscle strength was graded M4 or M3 for the biceps muscle in 85.4% of patients, for the deltoid muscle in 82.9% of patients, and for the upper parts of pectoral major in 92.7% of patients. The functional recovery of shoulder abduction in the patients with the additional suprascapular nerve neurotization was remarkably improved.

CONCLUSIONS

The modified prespinal route could significantly reduced the length of nerve graft in the contralateral C7 nerve root transfer to the injured upper trunk in brachial plexus root avulsion injury, and it may improve the functional outcomes, which deserves further investigations.

Contralateral C7 transfer via the prespinal and retropharyngeal route to repair brachial plexus root avulsion: a preliminary report

OBJECTIVE

We sought to investigate a shorter and safer route for contralateral C7 transfer.

METHODS

Eight male patients were treated from December 2005 to November 2006. Their ages ranged from 22 to 43 years (average, 30 yr). Five patients had total brachial plexus avulsion. The operative delay was from 2 to 6 months (mean, 4 mo). The bilateral scalenus anterior muscles were transected before a prespinal and retropharyngeal tunnel was made. The contralateral C7 nerve root was used to repair the upper trunk or the infraclavicular lateral cord and posterior cord of the injured side via this route, with the use of direct neurorrhaphy or nerve grafting.

RESULTS

The length of the harvested contralateral C7 nerve root was 4.67 +/- 0.52 cm in the first five patients. The nerve graft was 6.25 +/- 0.35 cm long for repairing supraclavicular brachial plexus and 8.56 +/- 0.45 cm long for repairing infraclavicular brachial plexus. The length of the harvested contralateral C7 nerve root averaged 6.85 cm in the last three patients, two of whom had direct neurorrhaphy to the C5 and six residual nerve roots; in the other patient, a nerve graft 3 cm in length was used. Transient contralateral sensory symptoms were reported in most patients. In all cases, shoulder abduction and elbow flexion recovered by 12 months postoperatively.

CONCLUSION

Transection of the bilateral scalenus muscles can reduce the length of the nerve graft and allow the C7 nerve to be transferred more smoothly and safely through the prespinal and retropharyngeal route; this method also favors nerve regeneration and functional recovery.

Contralateral C7 transfer in adult plexopathies

In the current study, a retrospective review of 56 patients with posttraumatic root avulsion brachial plexus injuries who underwent contralateral C7 transfer using the selective contralateral C7 technique is presented. The intraoperative findings of the involved brachial plexus, the surgical technique of preparation of the donor C7 nerve root, and the various neurotization procedures are reported. The surgical outcomes as well as the potential adverse effects of the procedure are analyzed. We conclude from this study that the selective contralateral C7 technique is a safe procedure that can be applied successfully for simultaneous reconstruction of several different contralateral muscle targets or for neurotization of cross chest nerve grafts for future free muscle transplantation.

Heterotopic nerve transfers: recent trends with expanding indication

There has been increasing enthusiasm for heterotopic nerve transfers for brachial plexus palsy as well as peripheral mononeural dysfunction. The concept of nerve transfer surgery is not new; the first publications on the topic date back to the early 1900s. A wide variety of potential donor nerves are available including the intercostal nerves, the spinal accessory nerve, the phrenic nerve, the ipsilateral medial pectoral nerve, partial ulnar nerve, partial median nerve, thoracodorsal nerve, radial nerve to the triceps, and the ipsilateral C7 or the contralateral C7 nerve roots. Treatment strategies include avoidance of interposed nerve grafting, isolated motor recipient nerve, early transfer, neurorrhaphy close to target motor end plates, and similar diameter between donor nerve and recipient nerves.