Retropharyngeal Contralateral C7 Nerve Transfer to the Lower Trunk for Brachial Plexus Birth Injury: Technique and Results

Promotive effect of skin precursor-derived Schwann cells on brachial plexus neurotomy and motor neuron damage repair through milieu-regulating secretome

Brachial plexus injury (BPI) with motor neurons (MNs) damage still remain poor recovery in preclinical research and clinical therapy, while cell-based therapy approaches emerged as novel strategies. Previous work of rat skin precursor-derived Schwann cells (SKP-SCs) provided substantial foundation for repairing peripheral nerve injury (PNI). Given that, our present work focused on exploring the repair efficacy and possible mechanisms of SKP-SCs implantation on rat BPI combined with neurorrhaphy post-neurotomy. Results indicated the significant locomotive and sensory function recovery, with improved morphological remodeling of regenerated nerves and angiogenesis, as well as amelioration of target muscles atrophy and motor endplate degeneration. Besides, MNs could restore from oxygen-glucose-deprivation (OGD) injury upon SKP-SCs-sourced secretome treatment, implying the underlying paracrine mechanisms. Moreover, rat cytokine array assay detected 67 cytokines from SKP-SC-secretome, and bioinformatic analyses of screened 32 cytokines presented multiple functional clusters covering diverse cell types, including inflammatory cells, Schwann cells, vascular endothelial cells (VECs), neurons, and SKP-SCs themselves, relating distinct biological processes to nerve regeneration. Especially, a panel of hypoxia-responsive cytokines (HRCK), can participate into multicellular biological process regulation for permissive regeneration milieu, which underscored the benefits of SKP-SCs and sourced secretome, facilitating the chorus of nerve regenerative microenvironment. Furthermore, platelet-derived growth factor-AA (PDGF-AA) and vascular endothelial growth factor-A (VEGF-A) were outstanding cytokines involved with nerve regenerative microenvironment regulating, with significantly elevated mRNA expression level in hypoxia-responsive SKP-SCs. Altogether, through recapitulating the implanted SKP-SCs and derived secretome as niche sensor and paracrine transmitters respectively, HRCK would be further excavated as molecular underpinning of the neural recuperative mechanizations for efficient cell therapy; meanwhile, the analysis paradigm in this study validated and anticipated the actions and mechanisms of SKP-SCs on traumatic BPI repair, and was beneficial to identify promising bioactive molecule cocktail and signaling targets for cell-free therapy strategy on neural repair and regeneration.

Retro Oesophageal Transfer of Contralateral C7 in Birth Brachial Plexus Injury - A Retrospective Study

Background: Presence of available healthy nerve roots on the injured side determines the outcome after nerve reconstruction. Paucity of nerve roots warrants contralateral C7 harvest for optimal results. We aim to study the risks and benefits of retro oesophageal transfer of contralateral C7 root in infants with birth brachial plexus injury. Methods: Study was carried out from 2017 to 2022 in 13 children who have undergone retro oesophageal transfer of contralateral C7 root to affected side. Follow-up period ranged from 8 to 60 months after the surgery. Motor power assessment was done using by active movement scale. Results: Average active movement score for abduction was found to be 6, elbow flexion 5.7, elbow extension 5.8, wrist extension 3, wrist flexion 4, finger flexion 4.8 and finger extension 3.8, respectively. No neurological deficits, limb length anomaly noted in the normal upper limb after contralateral C7 harvest. Conclusions: Retro oesophageal transfer of contralateral C7 is a safe technique in birth brachial plexus injury. The advantage of retro oesophageal transfer is reduction in the length of nerve grafts, thus helping in early neurotisation of distal forearm and hand muscles. The large axonal output from contralateral C7 can be used to reconstruct different nerves without any residual deficits on the normal side. Level of Evidence: Level IV (Therapeutic).

Rehabilitation protocols in neonates undergoing primary nerve surgery for upper brachial plexus palsy: A scoping review

INTRODUCTION

Surgical management is recommended in patients with severe neonatal brachial plexus palsy (NBPP) within the first 6 months of age to regain best possible function. Rehabilitation post-surgery remains relatively unexplored. This is a scoping review that explores, which rehabilitation modalities exist and how they vary for different microsurgical approaches in NBPP.

MATERIALS AND METHODS

A systematic search was conducted to include articles about upper trunk obstetric brachial plexus nerve microsurgery in pediatric patients that made mention of rehabilitation protocols. The aims of rehabilitation modalities varied and were grouped: "passive" movement to prevent joint contracture or stiffness, "active" or task-oriented movement to improve motor function, or "providing initial motor recovery". Surgical approach was described as either exploration of the brachial plexus (EBP) or nerve transfer without root exploration (NTwoRE). Technique was categorized into transfers and non-transfers.

RESULTS

Thirty-six full-text articles were included. Initiation of rehabilitation was 22.26 days post-surgery. Twenty-eight studies were EBP, and six were NTwoRE. Of studies classifiable by aims, nine were "passive", nine were "active", and five were "providing initial motor recovery". Only 27.7% of EBP studies mentioned active therapy, while 75.0% of NTwoRE studies mentioned active therapy. The average age of patients in the EBP procedure category was 7.70 months, and NTwoRE was 17.76 months. Within transfers, the spinal accessory to suprascapular group was more likely to describe an active shoulder exercise therapy, whereas contralateral C7 group was more likely to describe "initial motor recovery", especially through the use of electrostimulation. All articles on electrostimulation recommended 15-20-minute daily treatment.

CONCLUSION

Information on rehabilitation is limited post-nerve surgery in NBPP. However, when mentioned, the aims of these therapies vary with respect to surgical approach and technique. The type of therapy to employ may be a multifaceted decision, involving factors such as patient age, initial deformity, and goals of the care team.

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.

Donor complications of contralateral C7 nerve transfer in Brachial Plexus Birth Injury: a systematic review

PURPOSE

Contralateral C7 (CC7) nerve transfer is a reconstructive option in the upper limb when there are limited donor options. Promising results have been reported in the adult population but its role in Brachial Plexus Birth Injury (BPBI) is unclear. A major concern with this technique is the potential impact on the contralateral, unaffected limb. Our aim was to review the available literature on the use of this transfer in BPBI, to determine the incidence of short- and long-term deficits at the donor site.

METHODS

The relevant literature was identified from searches of Embase, Ovid Emcare and Ovid MEDLINE, for combinations of terms relating to CC7 nerve transfer and BPBI.

RESULTS

Seventy-five patients were included in this review, from the eight papers that were eligible for inclusion, from a total of 16 papers identified. Patient age ranged from three to 93 months and the shortest follow-up period was six months. Post-operative motor deficits at the donor site included reduced range of shoulder abduction; triceps weakness; and phrenic nerve palsy. All motor deficits recovered within six months. The only sensory deficit reported was reduced sensation in the median nerve distribution which, in all cases, resolved within four weeks. Finally, synchronous donor limb motion and sensation were reported in 46.6% of patients.

CONCLUSION

CC7 nerve transfer in BPBI appears to have few long-term donor limb complications. Sensory and motor deficits are reportedly transient. The impact of synchronous motion and sensation on upper limb function in this patient cohort is not yet known.

Examination of Upper Extremity Length Discrepancy in Patients with Obstetric Brachial Plexus Paralysis

Since the natural course of obstetric brachial plexus palsy is variable, several problems are encountered. One important question, in considering patients with OBPP under observation in outpatient clinical settings, is whether children will have length discrepancies in their arms. The aim of this study was to determine differences in the length of the affected extremity, in comparison to the opposite upper extremity. As such, 45 patients, aged 6 months to 18 years, with unilateral brachial plexus palsy developed due to obstetric reasons, were included in the study. Affected and healthy side humerus, ulna, radius, 2nd metacarpal and 5th metacarpal lengths were evaluated according to gender, age, side, Narakas classification, primary and secondary surgery. Statistically significant differences were found in the change rates of affected/healthy humerus, radius, 2nd metacarpal and 5th metacarpal lengths according to age (93%, 95%, 92%, 90% and 90%, respectively). Affected/healthy change rates of ulna, radius, 2nd metacarpal and 5th metacarpal lengths were found to differ statistically (p < 0.05) according to the Narakas classification variable (94%, 92%, 95%, 94% and 94%, respectively). There were no statistically significant differences in the ratios of affected/healthy change in the lengths of the humerus, ulna, radius and 5th metacarpal compared to the primary surgery (p > 0.05). The ratios of affected/healthy change in ulna, radius and 5th metacarpal lengths were found to differ statistically (p < 0.05) according to secondary surgeries (93%, 91%, 91% and 92%, respectively). Joint and bone deformities and bone shortening were observed after changes that occurred in the postnatal and growing periods due to obstetric brachial plexus palsy. Every increase in function to be gained in the upper extremity musculature was also potentially able to reduce problems, such as shortness.

Management of Brachial Plexus Birth Injury: The SickKids Experience

This article describes the approach utilized by the multidisciplinary team at Sick Kids Hospital to evaluate and treat patients with brachial plexus birth injury (BPBI). This approach has been informed by more than 30 years of experience treating over 1,800 patients with BPBI and continues to evolve over time. The objective of this article is to provide readers with a practical overview of the Sick Kids approach to the management of infants with BPBI.

Recent Advances in the Treatment of Brachial Plexus Birth Injury

LEARNING OBJECTIVES

After studying this article, the participant should be able to: 1. Describe methods of clinical evaluation for neurologic recovery in brachial plexus birth injury. 2. Understand the role of different diagnostic imaging modalities to evaluate the upper limb. 3. List nonsurgical strategies and surgical procedures to manage shoulder abnormality. 4. Explain the advantages and disadvantages of microsurgical nerve reconstruction and distal nerve transfers in brachial plexus birth injury. 5. Recognize the prevalence of pain in this population and the need for greater sensory outcomes evaluation.

SUMMARY

Brachial plexus birth injury (BPBI) results from closed traction injury to the brachial plexus in the neck during an infant's vertex passage through the birth canal. Although spontaneous upper limb recovery occurs in most instances of BPBI, some infants do not demonstrate adequate motor recovery within an acceptable timeline and require surgical intervention to restore upper limb function. This article reviews major advances in the management of BPBI in the past decade that include improved understanding of shoulder pathology and its impact on observed motor recovery, novel surgical techniques, new insights in sensory function and pain, and global efforts to develop standardized outcomes assessment scales.

Analysis of Results of Contralateral Hemi-C7 Root Used for Restoring Hand Function in Global Birth Brachial Plexus Palsy

PURPOSE

To analyze the outcome of the use of contralateral hemi-C7 for the restoration of hand function in patients with birth brachial plexus global palsy.

METHODS

From 2004 to 2017, 19 infants with Narakas types III and IV birth brachial plexus palsy underwent transfer of contralateral hemi-C7 (posterior division of the contralateral C7 root) to the lower trunk or medial cord on the affected side. All the patients were evaluated for shoulder function using the Gilbert and Mallet scores, elbow flexion using the modified Medical Research Council score for children, and hand function using the Raimondi score. After the surgery, the children were followed-up at 3-month intervals for the first year and 6-month intervals thereafter. Hand function achieving Raimondi scores of 3-5 was considered a useful outcome.

RESULTS

The patients were followed-up for a mean duration of 88 months, with a minimum of 35 and a maximum of 192 months of follow-up. All patients attained a Gilbert score of ≥3, whereas 9 patients attained a score of ≥4. Similarly, all patients attained a minimum aggregate Mallet score of 15, and 9 patients attained a score of ≥20. All patients attained a modified Medical Research Council score of ≥3, used for assessing elbow flexion. Useful hand function was attained in 73% (14/19) of the cases (a Raimondi score of ≥3). There was no clinically recorded deficit on the donor side.

CONCLUSIONS

Contralateral hemi-C7 transfer in infants with brachial plexus root avulsions helped regain useful hand function in 73% (14/19) of the children treated.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

Contralateral C7 Nerve Transfer for Stroke Recovery: New Frontier for Peripheral Nerve Surgery

Ischemic stroke remains a major cause of disability in the United States and worldwide. Following the large-scale implementation of stroke thrombectomy and the optimization of treatment protocols for acute stroke, the reduction in stroke-associated mortality has resulted in an increased proportion of stroke survivors, many of whom have moderate to severe disability. To date, the treatment of subacute and chronic stroke has remained a challenge. Several approaches, involving pharmacological interventions to promote neuroplasticity, brain stimulation strategies and rehabilitative interventions, are currently being explored at different stages of the translational spectrum, yet level 1 evidence is still limited. In a recent landmark study, surgical intervention using contralateral C7 nerve transfer, an approach used to treat brachial plexus injury, was implemented in patients with chronic stroke, demonstrating an added benefit to standard rehabilitation strategies, leading to improved motor performance and reduced spasticity. The procedure involved the transfer of the C7 nerve root and middle trunk from the uninjured extremity to the injured extremity using a short conduit that allows for faster regeneration and innervation of the injured upper extremity via the ipsilateral (contralesional) hemisphere. In this work, we review the rationale for using contralateral C7 nerve transfer in stroke, describe the surgical intervention with associated variations and limitations, and discuss the current evidence for the efficacy of this technique in ischemic stroke research.

Brachial Plexus Birth Injuries: A Critical Analysis Review

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The incidence of brachial plexus birth injury (BPBI) in the United States is declining and now occurs in <1 per 1,000 births.

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The gold standard for predicting the need for early intervention remains serial examination.

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Early treatment of BPBI with reconstructive surgery requires the ability to perform both interposition nerve grafting and nerve transfers.

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Given the heterogeneity of lesions, the evidence is largely limited to retrospective comparative studies and case series.

Morbidity of Nerve Transfers for Brachial Plexus Birth Injury: A Systematic Review

BACKGROUND

The purpose of this article is to systematically review the peer-reviewed literature on the morbidity of nerve transfers performed in patients with brachial plexus birth injury (BPBI). Nerve transfers for restoration of function in patients with BPBI that fail nonoperative management are increasing in popularity. However, relatively little attention has been paid to the morbidity of these transfers in the growing patient. The authors systematically review the current literature regarding donor site morbidity following nerve transfer for BPBI.

METHODS

A systematic review of the Medline and EMBASE databases was conducted through February 2020. Primary research articles written in English and reporting donor site morbidity after nerve transfer for BPBI were included for review.

RESULTS

Thirty-six articles met inclusion criteria, all of which were retrospective reviews or case reports. There was great heterogeneity in outcomes assessed. With 5 year or less follow-up, all transfers were relatively well tolerated with the exception of the hypoglossal nerve transfer.

CONCLUSION

Nerve transfers are a well-recognized treatment strategy for patients with BPBI and have an acceptable risk profile in the short term. Full hypoglossal nerve transfers for BPBI are of historical interest. Donor site morbidity is grossly underreported. This review highlights the need for more objective and systematic reporting of donor site outcomes, and the need for longer term follow-up in these patients.

LEVEL OF EVIDENCE

Systematic review. Level III-therapeutic.

Repair of peripheral nerve defects by nerve transposition using small gap bio-sleeve suture with different inner diameters at both ends

During peripheral nerve transposition repair, if the diameter difference between transposed nerves is large or multiple distal nerves must be repaired at the same time, traditional epineurial neurorrhaphy has the problem of high tension at the suture site, which may even lead to the failure of nerve suture. We investigated whether a small gap bio-sleeve suture with different inner diameters at both ends can be used to repair a 2-mm tibial nerve defect by proximal transposition of the common peroneal nerve in rats and compared the results with the repair seen after epineurial neurorrhaphy. Three months after surgery, neurological function, nerve regeneration, and recovery of nerve innervation muscle were assessed using the tibial nerve function index, neuroelectrophysiological testing, muscle biomechanics and wet weight measurement, osmic acid staining, and hematoxylin-eosin staining. There was no obvious inflammatory reaction and neuroma formation in the tibial nerve after repair by the small gap bio-sleeve suture with different inner diameters at both ends. The conduction velocity, muscle strength, wet muscle weight, cross-sectional area of muscle fibers, and the number of new myelinated nerve fibers in the bio-sleeve suture group were similar to those in the epineurial neurorrhaphy group. Our findings indicate that small gap bio-sleeve suture with different inner diameters at both ends can achieve surgical suture between nerves of different diameters and promote regeneration and functional recovery of injured peripheral nerves.