What has changed in brachial plexus surgery?

Outcomes of surgically managed adult traumatic brachial plexus injuries in an upper-middle-income country

Background

Traumatic brachial plexus injuries (TBPIs) are debilitating and complex to treat. The last five decades have seen advances in surgical management, and consequently improved functional outcomes in patients with these injuries. There is limited data available describing the outcomes of surgically managed TBPIs within the South African context. This study aimed to identify the common causes of injury, injury characteristics, and functional outcomes of surgically managed patients with TBPIs.

Methods

We conducted a retrospective chart review of all adult patients that underwent surgery for TBPIs over a period of ten years at a specialised hand unit in South Africa. The minimum follow-up period was one year. Patient demographic details, injury characteristics and functional outcomes were collected. Statistical analysis was performed to determine factors associated with functional outcomes. A good functional outcome for recovery was defined as a Medical Research Council (MRC) grade of three or more for the affected elements of the plexus at the most recent follow-up.

Results

Forty-seven patients of median age 32 years were included in the final analysis. Most patients were male (87.2 %). The majority of patients were injured in motor vehicle accidents (MVAs) or from penetrating stab wounds (48.9 % and 38.3 % respectively). The median pre-operative MRC grade of the affected elements of the brachial plexus was 0.0, and post-operatively was 2.0. Fourteen patients (14 of 47, 29.8 %) had a good outcome and 33 had a poor outcome (33 of 47, 70.2 %). There was no difference in outcome comparing penetrating injury mechanisms to closed traction or blunt injuries, (p = 0.386, OR 1.75, 95 % CI 0.49-6.20). All patients with pan-plexal injuries had a poor outcome (15 of 33, 46 %). All patients who received intercostal (6 of 33, 18 %) or phrenic nerve transfers (3 of 33, 9 %) had a poor outcome.

Conclusion

Adult traumatic BPIs in this South African sample typically presented more than two months after injury and were comprised of a high proportion of penetrating injuries. Just under a third of surgically managed patients had a good outcome. Pan plexal injuries have uniformly poor outcomes. We recommend early referral for all TBPIs to a unit that manages BPI to improve outcomes.

Functional and morphological evaluation of the trapezius muscle after spinal accessory nerve transfer to brachial plexus nerves

INTRODUCTION

The main innervation of the trapezius muscle is provided by the spinal accessory nerve. Several studies describe the contributions of cervical plexus roots to the trapezius muscle innervation, either directly or through connections with the spinal accessory nerve. There is no adequate understanding of how the trapezius muscle is affected after using the spinal accessory nerve in nerve transfer procedures with the usual technique, preserving at least 1 branch for the upper trapezius.

METHODS

We evaluated 20 patients with sequelae of traumatic brachial plexus injury who underwent surgical procedures for brachial plexus repair or free muscle transfer, which included the spinal accessory nerve transfer technique and were followed for a minimum of 1 year. The three portions trapezius muscle were evaluated by physical examination, magnetic resonance imaging (analysis of fatty degeneration) and electromyography.

RESULTS

In all evaluation methods, the middle and lower portions of the trapezius muscle showed more significant morphological and/or functional impairment than the upper portion, in most cases. There was a statistically significant difference in all the complementary exams results, between the affected side (with sacrifice of the nerve) versus the normal side, in the middle and lower portions of the trapezius muscle.

CONCLUSIONS

Physical examination alone is not sufficient to determine the residual functionality of the trapezius muscle. Magnetic resonance imaging and electromyography are useful tools to assess both morphological involvement of the trapezius muscle and nerve conduction impairment of the trapezius muscle, respectively. The results suggest that the middle and lower portions of the trapezius muscle are affected by previous SAN transfer and should be considered with caution for further muscle transfer procedures.

Long-term functional recovery in C5-C6 avulsions treated with distal nerve transfers

BACKGROUND

In patients suffering from traction lesions of the brachial plexus, complete C5 and/or C6 root avulsion patients with C7 root preservation are relatively uncommon occurrences, but represent excellent candidates for surgical treatment, with satisfactory results. Shoulder abduction and extra-rotation, elbow flexion and forearm supination are lost functions restorable with surgical treatment.

METHODS

This single-center, prospective observational study involved a series of 27 young adults with C5 and/or C6 root complete avulsion and C7 preservation, which underwent surgical repair with double or triple nerve transfer.

RESULTS

Patients recovered a useful elbow flexion. Electromyographic and clinical signs of biceps reinnervation were observed in each UN-MC nerve transfer. The abduction strength recovery was M5 in 10 patients, M4 in 14 patients and M3 in 3 patients. The external rotation strength recovery was M5 in 4 patients, M4 in 18 patients, M3 in 3 patients and M2 in 2 patients. The elbow flection strength was M5 in 5 patients, M4 in 15 patients and M3 in 7 patients. Elbow extension was preserved in all cases.

CONCLUSIONS

The concept of 'peripheral rewiring procedures' represents an advance in the repair of the peripheral nerve injuries. Triple nerve transfer can be nowadays considered a standard treatment for isolated C5-C6 avulsions. We report our experience with the second-biggest casuistry in the literature on patients treated with this technique. We consider our outcome concerning functional recovery to be satisfying and comparable to data reported in the literature.

Differences in the surgical treatment of adult and pediatric brachial plexus injuries among peripheral nerve surgeons

OBJECTIVES

Peripheral nerve surgeons disagree on the optimal timing and treatment of brachial plexus injuries (BPI). This study aims to survey peripheral nerve surgeons on their management of BPI, including disagreement.

METHODS

Surgeons responded to a case-based survey involving traumatic and birth injuries leading to BPI involving the upper and lower trunks, and pre- and post-ganglionic injuries.

RESULTS

Out of 255 invited surgeons, 154 participated, with specialties of Neurosurgery (33.7%), Plastic surgery (32.5%), and Orthopedics (32.5%). For the adult C5-6 avulsion injury, 97.4% agreed they would operate. There was 46.2% disagreement regarding the pediatric upper trunk neuroma-in-continuity case, and similar disagreement (50.0%) was recorded on exploring the brachial plexus for a pediatric lower trunk injury case. High percentages of surgeons were more likely to explore the plexus, such as at upper BPI. Also, most participants reported nerve transfer for the upper and lower trunk avulsion injuries, but there was 55.6% disagreement regarding nerve transfer for the infant with the upper trunk neuroma-in-continuity. Among those elected to perform nerve transfer, most (70.0%-84.5%) would perform an accessory-to-suprascapular nerve transfer for upper BPI, while brachialis-to-anterior interosseous and supinator branch of the radial nerve-to-posterior interosseous were preferred for lower BPI (30.0%-55.9%).

CONCLUSIONS

Substantial disagreement exists among peripheral nerve surgeons in managing adult and pediatric BPI. In adult BPI, most prefer to operate at the time of the presentation and perform extensive nerve transfers. The accessory-suprascapular transfer was recommended for upper BPI, while brachialis and radial nerves were preferred for lower BPI. The most significant disagreements exist in operation and nerve transfer for pediatric upper BPI and brachial plexus explorations. Geography, specialty, and operative volume contribute to the differences seen.

Free gracilis muscle transfer with ulnar nerve neurotization for elbow flexion restoration

PURPOSE

In upper and chronic brachial plexus injuries for which neurological surgery is not a good treatment option, one possibility for gaining elbow flexion is free functional muscle transfer. The primary aim of our study was to evaluate the elbow flexion gain achieved by free gracilis muscle transfer with partial ulnar nerve neurotization.

METHODS

This surgery was performed in 21 patients with upper and chronic (> 12 months) brachial plexus injuries. The level of injury, patient age, the time between trauma and surgery, the affected side, and the aetiology of the lesion were recorded. The primary outcome evaluated was elbow flexion muscle strength, which was measured using the British Medical Research Council (BMRC) scale, in patients with a minimum follow-up period of 12 months. The criterion used to classify elbow flexion as good was a grade of M4 or higher.

RESULTS

An M4 elbow flexion strength gain was observed in 61.9% of the patients. A gain of M2 or higher was observed in 95.2% of the patients. The mean range of active motion was 77° (range 10 minimum-110 maximum).

CONCLUSION

In patients with upper and chronic brachial plexus injuries, free gracilis muscle transfer with ulnar nerve neurotization yields a satisfactory gain in elbow flexion strength and is therefore a good treatment option.

Clinical and neurobiological advances in promoting regeneration of the ventral root avulsion lesion

Root avulsions due to traction to the brachial plexus causes complete and permanent loss of function. Until fairly recent, such lesions were considered impossible to repair. Here we review clinical repair strategies and current progress in experimental ventral root avulsion lesions. The current gold standard in patients with a root avulsion is nerve transfer, whereas reimplantation of the avulsed root into the spinal cord has been performed in a limited number of cases. These neurosurgical repair strategies have significant benefit for the patient but functional recovery remains incomplete. Developing new ways to improve the functional outcome of neurosurgical repair is therefore essential. In the laboratory, the molecular and cellular changes following ventral root avulsion and the efficacy of intervention strategies have been studied at the level of spinal motoneurons, the ventral spinal root and peripheral nerve, and the skeletal muscle. We present an overview of cell-based pharmacological and neurotrophic factor treatment approaches that have been applied in combination with surgical reimplantation. These interventions all demonstrate neuroprotective effects on avulsed motoneurons, often accompanied with various degrees of axonal regeneration. However, effects on survival are usually transient and robust axon regeneration over long distances has as yet not been achieved. Key future areas of research include finding ways to further extend the post-lesion survival period of motoneurons, the identification of neuron-intrinsic factors which can promote persistent and long-distance axon regeneration, and finally prolonging the pro-regenerative state of Schwann cells in the distal nerve.