Electrophysiologic recovery of the abductor pollicis brevis after contralateral C7 nerve transfer in 95 patients with global brachial plexus avulsion

Anatomical Study of Cross-Transfer of the Contralateral C7 Nerve Through the Posterior Epidural Pathway of the Cervical Spine for the Treatment of Spastic Paralysis of the Upper Limbs

BACKGROUND

This study explored the safety and feasibility of surgical treatment of spastic paralysis of the central upper extremity by contralateral cervical 7 nerve transfer via the posterior epidural pathway of the cervical spine.

METHODS

Five fresh head and neck anatomical specimens were employed to simulate contralateral cervical 7 nerve transfer through the posterior epidural pathway of the cervical spine. The relevant anatomical landmarks and surrounding anatomical relationships were observed under a microscope, and the relevant anatomical data were measured and analysed.

RESULTS

The posterior cervical incision revealed the cervical 6 and 7 laminae, and lateral exploration revealed the cervical 7 nerve. The length of the cervical 7 nerve outside the intervertebral foramen was measured to be 6.4 ± 0.5 cm. The cervical 6 and cervical 7 laminae were opened with a milling cutter. The cervical 7 nerve was extracted from the inner mouth of the intervertebral foramen, and its length was 7.8 ± 0.3 cm. The shortest distance of the cervical 7 nerve transfer via the posterior epidural pathway of the cervical spine was 3.3 ± 0.3 cm.

CONCLUSIONS

Cross-transfer surgery of the contralateral cervical 7 nerve via the posterior epidural pathway of the cervical spine can effectively avoid the risk of nerve and blood vessel damage in anterior cervical nerve 7 transfer surgery; the nerve transfer distance is short, and nerve transplantation is not required. This approach may become a safe and effective procedure for the treatment of central upper limb spastic paralysis.

Prespinal Versus Conventional Hemicontralateral C7 Nerve Transfer in the Treatment of Total Brachial Plexus Roots Avulsion Injuries: A Retrospective Study With a Minimum Follow-Up Period of 4 Years

PURPOSE

Contralateral C7 (CC7)-to-median nerve transfer has been commonly used to restore hand function in brachial plexus injury. To shorten the nerve graft, the prespinal route was described and achieved direct coaptation when combined with humeral shortening osteotomy. The limb was positioned at 0° shoulder abduction and neutral head position. Given our concern about donor-site morbidity when harvesting the whole CC7 nerve and tension across the neurorrhaphy site after mobilization, we aimed to describe our modified prespinal route and compare its outcomes and complications with the conventional hemi-CC7 transfer.

METHODS

From 2004 to 2014, 39 patients with preganglionic total brachial plexus root avulsion injuries, with a minimum of 4 years of follow-up, were included. Overall, 20 and 19 patients underwent the conventional hemi-CC7-to-median nerve and hemi-CC7-to-lower trunk (LT) transfer through the modified prespinal route, respectively. The modified prespinal route was combined with bilateral clavicle shortening osteotomy to achieve direct coaptation to the LT at 45° shoulder abduction.

RESULTS

The modified prespinal route showed the median period to achieve ≥M3 hand grip assessed in clinical follow-up was shorter (26.5 months vs 45.5 months), and a higher proportion of patients achieved ≥M3 hand grip recovery (63% vs 30%). One patient experienced symptomatic phrenic nerve injury; however, the hemidiaphragm fully recovered after 6 months. The long-term donor-site complication rate was 2.6%, including one sensory abnormality, and no permanent donor-site weakness after hemi-CC7 harvesting was observed.

CONCLUSIONS

The modified prespinal route combined with clavicle osteotomy allowed direct coaptation to the LT and did not require head immobilization. It may allow a higher proportion of patients to achieve ≥M3 hand grip more quickly than conventional hemi-CC7 transfer.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

Restoration of intrinsic hand function by superficial radial nerve: an anatomical study

BACKGROUND

The contralateral seventh cervical (cC7) nerve root transfer represents a cornerstone technique in treating total brachial plexus avulsion injury. Traditional cC7 procedures employ the entire ulnar nerve as a graft, which inevitably compromises its restorative capacity.

OBJECTIVE

Our cadaveric study seeks to assess this innovative approach aimed at preserving the motor branch of the ulnar nerve (MBUN). This new method aims to enable future repair stages, using the superficial radial nerve (SRN) as a bridge connecting cC7 and MBUN.

METHODS

We undertook a comprehensive dissection of ten adult cadavers, generously provided by the Department of Anatomy, Histology, and Embryology at Fudan University, China. It allowed us to evaluate the feasibility of our proposed technique. For this study, we harvested only the dorsal and superficial branches of the ulnar nerve, as well as the SRN, to establish connections between the cC7 nerve and recipient nerves (both the median nerve and MBUN). We meticulously dissected the SRN and the motor and sensory branches of the ulnar nerve. Measurements were made from the reverse point of the SRN to the wrist flexion crease and the coaptation point of the SRN and MBUN. Additionally, we traced the MBUN from distal to proximal ends, recording its maximum length. We also measured the diameters of the nerve branches and tallied the number of axons.

RESULTS

Our modified approach proved technically viable in all examined limbs. The distances from the reverse point of the SRN to the wrist flexion crease were 8.24 ± 1.80 cm and to the coaptation point were 6.60 ± 1.75 cm. The maximum length of the MBUN was 7.62 ± 1.03 cm. The average axon diameters in the MBUN and the anterior and posterior branches of the SRN were 1.88 ± 0.42 mm、1.56 ± 0.38 mm、2.02 ± 0.41 mm,respectively. The corresponding mean numbers of axons were 1426.60 ± 331.39 and 721.50 ± 138.22, and 741.90 ± 171.34, respectively.

CONCLUSION

The SRN demonstrated the potential to be transferred to the MBUN without necessitating a nerve graft. A potential advantage of this modification is preserving the MBUN's recovery potential.

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.