Original article
Injury mechanisms in supraclavicular stretch injuries of the brachial plexusMécanismes traumatiques dans les lésions supraclaviculaires étendues du plexus brachial

https://doi.org/10.1016/j.hansur.2015.09.001Get rights and content

Abstract

The aim of this study was to describe the mechanisms involved in stretch injuries of the brachial plexus. One hundred and fifty consecutive patients with supraclavicular brachial plexus injuries (BPI) were asked about the mechanism of injury during the actual injury event, particularly about the type of trauma to their shoulder, shoulder girdle and head. Fifty-seven of the patients provided enough information about their accident to allow for analysis of the shoulder trauma. The injury mechanism for all patients having upper root or total palsy (n = 46) was described as a direct vertical impact to the shoulder. In 44 of these patients, the trauma followed a motorcycle accident and, in most of them, the patient hit a fixed vertical structure before falling to the ground. The injury mechanism for the lower root palsy cases (n = 11) was variable. The most frequent mechanism was forceful anterior shoulder compression by a car seat belt. We found that injury mechanisms differed significantly from the ones commonly discussed in published studies.

Résumé

Notre objectif était de décrire les mécanismes impliqués dans les lésions supraclaviculaires étendues du plexus brachial. Cent cinquante patients consécutifs avec lésion supraclaviculaire du plexus brachial (LSCPB) ont été interrogés concernant le mécanisme au moment de l’épisode traumatique pour décrire le type et le moment du traumatisme au niveau de l’épaule, la ceinture scapulaire et de la tête. Le mécanisme traumatique impliqué pour tous les patients ayant une paralysie des racines supérieures ou une paralysie totale (n = 46) a été décrit comme un impact direct vertical à l’épaule. Chez 44 de ces patients, le traumatisme faisait suite à un accident de moto et, dans la plupart d’entre eux, il y a d’abord eu un impact contre une structure verticale avant la chute sur le sol. Les mécanismes traumatiques impliqués dans les paralysies des racines inférieures (n = 11) étaient variables. Le mécanisme le plus fréquent était une forte compression antérieure de l’épaule par la ceinture de sécurité de la voiture. Nous avons constaté que les mécanismes traumatiques diffèrent sensiblement de ceux jusqu’alors acceptés par la littérature.

Introduction

Traumatic brachial plexus injuries (BPI) are a consequence of traction forces that result in nerve ruptures or root avulsions [1]. Traction forces can be generated by direct or indirect trauma to the shoulder girdle [2]. Depending on the type of trauma, variable patterns of BPI can occur. Theories about the injury mechanism correlating the pattern of plexus injury and type of palsy were established in middle 19th century and continue to persist with scarce contemporary contributions [3].

We investigated the injury mechanisms involved in BPI in a cohort of patients and found that they differed significantly from the classical concepts.

Section snippets

Patients and methods

From September 2006 to June 2009, 150 consecutive patients with supraclavicular lesions of the brachial plexus were prospectively evaluated and operated at our hospital. All except four were male. Their average age was 26.8 years (SD ± 9.3 months) and the interval between their accident and surgery was 5.4 months on average (SD ± 2.8). Prior to surgery, patients were examined clinically and underwent a helical CT-myelogram following intradural contrast product injection.

Patients were asked about

Results

Among the 150 patients, 57 of them remembered enough details of their accident and provided us with sufficient information to allow for analysis of the shoulder trauma. The accident data are summarized in Table 1. None of the patients was able to provide information about the position or movement of their head during the trauma.

Discussion

In late 19th century, cadaver studies showed that brachial plexus injuries could not be provoked by the impact of the clavicle on the brachial plexus and first rib, but instead were due to neural traction [1]. Afterwards, the mechanical factors determining the level of injury were described. Barnes (1949) stated that root plexus injury was due to separation between shoulder and head, while the arm position at the moment of the collision determined which roots were injured [3]. With the arm

Conclusion

We speculate that lesions of the C5 and C6 roots follow shoulder depression by a direct impact force, whereas those involving C7-T1 mostly occur from posterior forceful retropulsion of the shoulder girdle by a compressive force. Sudden depression of the shoulder can injure all the roots, as we observed in patients who were hit by a falling tree branch that struck their shoulder and caused multiple fractures.

Disclosure of interest

The authors declare that they have no competing interest.

Acknowledgements

Ernesto Ernirock for his patience and brilliance while making the drawings.

References (9)

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