Incidence, Etiology, and Management of Long Thoracic and Accessory Nerve Injuries and Winging Scapula

Upper extremity musculoskeletal disorders (UE-MSDs) with limited shoulder movement and scapular winging due to upper brachial plexus, long thoracic, and accessory nerve injuries can be devastating and if left untreated can cause lifelong disability with pain that negatively impacts patients' daily activities and quality of life.^1,2 Peripheral nerve injuries make up a large portion of UE-MSDs. The health and economic burdens of peripheral nerve injuries are rising.³ Understanding the incidence and causation of these injuries is essential, as these primarily affect young workers and athletes with skeletal immaturity, causing significant morbidity. 

Kaiser et al⁴ recently reviewed and reported data from 10 studies involving 3032 patients regarding the prevalence of specific types and causes of brachial plexus injuries (BPIs) in adults. These injuries typically affect the younger, working-age population and can have a severe socio-economic impact. Increases in sports participation and in the number of motor vehicle accidents have resulted in a global rise in the incidence of  BPIs.^5-14 Upper-limb peripheral nerve injuries due to prone positioning have also occurred in COVID-19 patients in intensive care. ¹⁵

Muscles begin to undergo atrophy if diagnosis and treatments of peripheral nerve injuries are delayed. Early diagnosis and a referral to a peripheral nerve surgeon are important in cases that may necessitate surgical intervention. The complexity of the injury, nature of the surgical reconstruction, and the prolonged time off from work have the potential to accumulate substantial direct (2018 median: $38816 per patient) and indirect costs (2018 median: $801723 per patient) to the individual and society, respectively.^16,17 Recent data from the Monte Carlo simulation suggest that surgery and other interventions may maximize  patients’ ability to return to work after traumatic brachial plexus and accessory nerve injuries, which may result in decreases in indirect costs.¹⁶ 

The diagnosis of peripheral nerve injury can be obtained using nerve conduction velocity (NCV) test, electromyography (EMG), and  magnetic resonance (MR) neurography. Several treatment approaches are available including conservative treatments (physical therapy, orthotics, and pain control), early surgical intervention (neurolysis, nerve graft, and nerve transfer), and late surgical options (arthrodesis, tendon, and free muscle transfers). Early surgical intervention may provide the best means of obtaining a functional return. ^{13, 18-20} In this study 18 causes of UE-MSDs with limited shoulder movements and winging scapula were found in 789 of patients. Of these, 481 (61%) were male and 308 (39%) were female. (Table 1).

Type of examination and scales used for evaluation. Initial evaluation obtained for all patients included demographics (gender, age) and detailed medical history (cause, onset, and left/right or bilateral side of the injury. Physical and clinical examinations were performed by the lead author and the surgeon (RKN). Male patients were asked to remove their shirts, and females were asked to wear halter tank tops during the physical examination of the winging scapula/of the posterior thorax. The extent of scapular winging was assessed while the patient forward flexed his/her arms to the horizontal and pushed on a wall in a push-up motion. A 4-point numerical scale was used for determining the extent of scapula winging: 1 – severe; 2 – moderate; 3 – mild; and 4 – minimal/normal 17 (Figure 1 and Video 1, Video 2, Video 3, Video 4). NCV and EMG examination reports were obtained for the patients to assess the regional sensory or motor loss of the nerve injury.

Patients were asked to send a short video of the following movements by filming from behind without a shirt (male) or with a halter tank top (female) so that the shoulder blade is visible. A video was also taken of these patients performing the following movements before and after surgery.

Movement 1. Patients were asked to raise their arms straight in front at a right angle to their body, then raise them as high as possible, return them to resting position in the same way. 

Movement 2.  Patients were asked to raise their arms to the side through a "T" position then raise them as high as possible and return them to the resting position through the same "T" position. 

Movement 3.  Facing a wall, patients were asked to raise their arms to the front at a right angle to their body and continue to raise them as high as possible above their head (as in movement 1), and then take them down to the side through a "T" position (as in movement 2) without bringing their arms completely down and return them to the front. Then, they were asked to perform a press-up against a wall.

Stills were taken from the video of these patients performing these movements (0° being relaxed at the side and 180° being fully abducted above the head). They were evaluated for shoulder flexion in the sagittal plane and abduction in the frontal plane while videotaped from the posterior and superior views.

Video 1: A patient with severe scapular winging (ESW- 1) performing ROM - < 30ᵒ. 

Video 2: A patient with moderate scapular winging (ESW- 2) performing ROM - 90ᵒ. 

Video 3: A patient with mild scapular winging (ESW- 3) performing ROM - 120ᵒ. 

Video 4: A patient with minimal scapular winging/normal (ESW- 4) performing ROM- 180ᵒ. 

Eighteen causes of peripheral nerve injury were identified among the 789 patients with UE-MSDs. The most affected patients (12.7%) were involved in sports and related activities, with 20 different types of sports and related activities reported in this patient population. Weightlifting caused the most number of injuries (10.9%) in this group.  Incidences in the least affected patients were due to massage and viral infection, at 0.6% and 0.6% respectively. 

Comparatively, Kaiser et al³ recently reported data from 10 studies of 3032 patients with BPIs. The prevalence of closed BPIs was 93%, with lacerations accounting for 3% and a prevalence of male and female patients at 93% and 7%, respectively. The most common cause of BPI was motorcycle accidents with 67% occurrence, followed by car crashes at 14%. 

Sports and recreational-related physical activities are essential components of a healthy lifestyle, and may help decrease the incidence of obesity, diabetes, and cardiovascular diseases. Injury and fear of impairment; however, can be barriers in the participation of these activities.  Surgery and other interventions can help maximize return to work and regular activities after UE-MSDs.

Authors: Rahul K. Nath MD, Chandra Somasundaram PhD

Affiliations: Texas Nerve and Paralysis Institute, Houston, Texas, 77030

Correspondence: Rahul K. Nath MD, 6400 Fannnin St Ste 2420, Houston, Texas, 77030; drnath@drnathmedical.com

Disclosure: The authors disclose no financial or other conflicts of interest.