In medicine, a stinger, [1] [2] also called a burner or nerve pinch injury, is a neurological injury suffered by athletes, mostly in high-contact sports such as ice hockey, rugby, American football, and wrestling. The spine injury is characterized by a shooting or stinging pain that travels down one arm, followed by numbness and weakness in the parts of the arms, including the biceps, deltoid, and spinati muscles. Many athletes in contact sports have suffered stingers, but they are often unreported to medical professionals.
Anyone who experiences significant trauma to his or her head or neck needs immediate medical evaluation for the possibility of a spinal injury. In fact, it is safest to assume that trauma victims have a spinal injury until proven otherwise because:
The three main mechanisms of a stinger include receiving direct blows, extension, and compression of the brachial plexus, with most of the brachial plexus injuries being an extension-compression mechanism.
A stinger is an injury that is caused by restriction of the nerve supply to the upper extremity via the brachial plexus. The brachial plexus is formed by the anterior rami of the nerves at the 5th cervical level of the spinal cord all the way to the nerves at the 1st thoracic level of the spinal cord. The brachial plexus innervates the upper extremity as well as some muscles in the neck and shoulder. [4] Damage to the brachial plexus can occur when the nerves are stretched too far from the head and neck; specifically the upper trunk of the plexus – nerve roots at the 5th and 6th cervical level – are primarily affected. The upper trunk provides part of the nerve to supply to the upper extremity via the Musculocutaneous, Axillary, Radial and Median nerves. [5] It is for this reason that stingers do not affect both arms simultaneously, however it is possible for both arms to accrue injuries. Repeated nerve trauma can cause recurring stingers, chronic pain, and muscle weakness, while recovery can take weeks to months in severe cases. [6]
Since stingers are a nerve injury, a stinger can fall into two different categories of peripheral nerve injury with physiological differences. Grade I is neurapraxia, which involves focal damage of the myelin fibers around the axon, with the axon and the connective tissue sheath remaining intact. The disruption of nerve function involves demyelination. Axonal integrity is preserved, and remyelination occurs within days or weeks. [7] [8] Grade II is categorized by axonotmesis which is the most severe case of nerve injury in the context of stingers and involves the injury of the axon. [7] Grade III is classified as neurotmesis where there is a complete disruption of the axon, where it is unlikely of recovery. If this is to happen it is not considered a stinger, and usually is a high-energy injury to the shoulder girdle. [8]
Stingers are best diagnosed by a medical professional. This person will assess the athlete's pain, range of head and neck motion, arm numbness, and muscle strength. Often, the affected athlete is allowed to return to play within a short time, but persistent symptoms will result in removal. Athletes are also advised to receive regular evaluations until symptoms have ceased, specifically, the restoration of pain-free mobility. [2] If they have not after two weeks, or increase, additional tests such as magnetic resonance imaging (MRI) can be performed to detect a more serious injury, such as a herniated disc.
The order of treatments applied depends on whether the athlete's main complaint is pain or weakness. Both can be treated with an analgesic, anti-inflammatory medication, ice and heat, restriction of movement, and if necessary, cervical collar or traction. Surgery is only necessary in the most severe cases.
Returning from this injury depends on the number of burners that occurs. If a stinger occurs, the athletes usually return to play after they restore full strength, are asymptomatic where no pain persists, and painless range of motion in the cervical spine. At low frequencies of stingers, like 1 or 2, there is a much lower risk of the symptoms reoccurring. If three or more stingers occur in one season, one has a higher increased risk at the symptoms persisting. [9]
If one is returning from play to contact sports it is important to adopt a strict exercise regimen of the neck muscles so the player has the ability to handle the trauma associated with tackles. [10]
Stingers can be prevented by several of the following factors, but first, it is crucial to identify the severity of the stinger because treatment usually depends on that factor. If strengthening treatment starts too early with a severe case, it can prevent one from healing. The dysfunctions that caused the peripheral nerve injury must be identified to treat and prevent future injury. [11]
Flexibility and strength of the neck, shoulder, and upper extremity are essential because stiffness and weakness are predisposing factors for a burner as well as consequences of this injury. Factors that could help in the prevention of stingers could include strengthening the muscles, increasing the range of motion, and improving technique when playing. [12]
Simple measures can be taken to help in the recovery from stingers. A chest-out posture should be adapted to prevent the neck from extending too far because it brings the head over the shoulders. The chest-out posture is emphasized due to it not being commonly adopted by athletes due to developed shoulders and is perpetuated by brachial plexus irritation. The chest-out posture also reduces pressure on the brachial plexus by opening the thoracic outlet. [13]
Finally, stingers can be prevented by wearing protective gear, such as butterfly restrictors, designed to protect the head and neck from being forced into unnatural positions. This equipment is more feasible in positions where unrestricted head and neck movement is not required, such as American football lineman, than in positions like quarterback, where such movement is integral. Regardless of equipment, it is important to report even minor symptoms to an athletic trainer or team physician, and to allow appropriate recovery time.[ citation needed ]
Stingers commonly occur in contact sports like wrestling, hockey, basketball, boxing, rugby, weightlifting, and, most notably, football. One study found that up to 65% of college football players have suffered at least one stinger. However, it is difficult to ping an exact number of athletes that suffer from stingers as stingers are historically under-reported. This could be due to the players fear of being removed from play or the injury being viewed as unimportant. [14]
The following study found different frequencies in the number of stingers that occur. Incidence of stingers over a six-year study period with only 1.5 stingers per team each season. Most of the stingers reported were either during competitions or preseason. Exactly 93% of stingers were due to player contact, specifically 36.7% occurring while tackling and 25.8% occurring while blocking. [15]
In 1976 most major American football leagues banned the technique of spearing in the sport due to the risk of injury. When a player makes head-down contact, that player has much more of a chance of a significant spinal cord injury. After the initial rule change, many of the cervical spine injuries stopped. [16] Therefore, this prompted a new tackling technique to be adopted, such as the head-up tackling technique. This technique does prevent catastrophic spine injuries, but it can result in brachial plexus injuries. After the rule change, it has been estimated that stingers have gone up in prevalence. [17]
The peripheral nervous system (PNS) is one of two components that make up the nervous system of bilateral animals, with the other part being the central nervous system (CNS). The PNS consists of nerves and ganglia, which lie outside the brain and the spinal cord. The main function of the PNS is to connect the CNS to the limbs and organs, essentially serving as a relay between the brain and spinal cord and the rest of the body. Unlike the CNS, the PNS is not protected by the vertebral column and skull, or by the blood–brain barrier, which leaves it exposed to toxins.
The brachial plexus is a network of nerves formed by the anterior rami of the lower four cervical nerves and first thoracic nerve. This plexus extends from the spinal cord, through the cervicoaxillary canal in the neck, over the first rib, and into the armpit, it supplies afferent and efferent nerve fibers to the chest, shoulder, arm, forearm, and hand.
A spinal nerve is a mixed nerve, which carries motor, sensory, and autonomic signals between the spinal cord and the body. In the human body there are 31 pairs of spinal nerves, one on each side of the vertebral column. These are grouped into the corresponding cervical, thoracic, lumbar, sacral and coccygeal regions of the spine. There are eight pairs of cervical nerves, twelve pairs of thoracic nerves, five pairs of lumbar nerves, five pairs of sacral nerves, and one pair of coccygeal nerves. The spinal nerves are part of the peripheral nervous system.
The phrenic nerve is a mixed motor/sensory nerve that originates from the C3-C5 spinal nerves in the neck. The nerve is important for breathing because it provides exclusive motor control of the diaphragm, the primary muscle of respiration. In humans, the right and left phrenic nerves are primarily supplied by the C4 spinal nerve, but there is also a contribution from the C3 and C5 spinal nerves. From its origin in the neck, the nerve travels downward into the chest to pass between the heart and lungs towards the diaphragm.
The dorsal scapular nerve is a branch of the brachial plexus, usually derived from the ventral ramus of cervical nerve C5. It provides motor innervation to the rhomboid major muscle, rhomboid minor muscle, and levator scapulae muscle.
The long thoracic nerve is a branch of the brachial plexus derived from cervical nerves C5-C7 that innervates the serratus anterior muscle.
The sternocleidomastoid muscle is one of the largest and most superficial cervical muscles. The primary actions of the muscle are rotation of the head to the opposite side and flexion of the neck. The sternocleidomastoid is innervated by the accessory nerve.
Cervical spine disorders are illnesses that affect the cervical spine, which is made up of the upper first seven vertebrae, encasing and shielding the spinal cord. This fragment of the spine starts from the region above the shoulder blades and ends by supporting and connecting the skull.
Spondylosis is the degeneration of the vertebral column from any cause. In the more narrow sense it refers to spinal osteoarthritis, the age-related degeneration of the spinal column, which is the most common cause of spondylosis. The degenerative process in osteoarthritis chiefly affects the vertebral bodies, the neural foramina and the facet joints. If severe, it may cause pressure on the spinal cord or nerve roots with subsequent sensory or motor disturbances, such as pain, paresthesia, imbalance, and muscle weakness in the limbs.
Neurapraxia is a disorder of the peripheral nervous system in which there is a temporary loss of motor and sensory function due to blockage of nerve conduction, usually lasting an average of six to eight weeks before full recovery. Neurapraxia is derived from the word apraxia, meaning “loss or impairment of the ability to execute complex coordinated movements without muscular or sensory impairment”.
Klumpke's paralysis is a variety of partial palsy of the lower roots of the brachial plexus. The brachial plexus is a network of spinal nerves that originates in the back of the neck, extends through the axilla (armpit), and gives rise to nerves to the upper limb. The paralytic condition is named after Augusta Déjerine-Klumpke.
The scalene muscles are a group of three muscles on each side of the neck, identified as the anterior, the middle, and the posterior. They are innervated by the third to the eighth cervical spinal nerves (C3-C8).
A brachial plexus injury (BPI), also known as brachial plexus lesion, is an injury to the brachial plexus, the network of nerves that conducts signals from the spinal cord to the shoulder, arm and hand. These nerves originate in the fifth, sixth, seventh and eighth cervical (C5–C8), and first thoracic (T1) spinal nerves, and innervate the muscles and skin of the chest, shoulder, arm and hand.
The medial pectoral nerve is (typically) a branch of the medial cord of the brachial plexus and is derived from spinal nerve roots C8-T1. It provides motor innervation to the pectoralis minor muscle, and the lower half of the pectoralis major muscle. It runs along the inferior border of the pectoralis minor muscle.
The lower subscapular nerve, also known as the inferior subscapular nerve, is the third branch of the posterior cord of the brachial plexus. It innervates the inferior portion of the subscapularis muscle and the teres major muscle.
The upper (superior) subscapular nerve is the first branch of the posterior cord of the brachial plexus. The upper subscapular nerve contains axons from the ventral rami of the C5 and C6 cervical spinal nerves. It innervates the superior portion of the subscapularis muscle. The inferior portion of the subscapularis is innervated by the lower subscapular nerve.
The subclavian nerve, also known as the nerve to the subclavius, is a small branch of the upper trunk of the brachial plexus. It contains axons from C5 and C6. It innervates the subclavius muscle.
A spinal disc herniation is an injury to the intervertebral disc between two spinal vertebrae, usually caused by excessive strain or trauma to the spine. It may result in back pain, pain or sensation in different parts of the body, and physical disability. The most conclusive diagnostic tool for disc herniation is MRI, and treatment may range from painkillers to surgery. Protection from disc herniation is best provided by core strength and an awareness of body mechanics including good posture.
The spinal cord is a long, thin, tubular structure made up of nervous tissue that extends from the medulla oblongata in the brainstem to the lumbar region of the vertebral column (backbone) of vertebrate animals. The center of the spinal cord is hollow and contains a structure called the central canal, which contains cerebrospinal fluid. The spinal cord is also covered by meninges and enclosed by the neural arches. Together, the brain and spinal cord make up the central nervous system.
Cervical spondylotic myelopathy (CSM) is a disorder characterised by the age-related deterioration of the cervical spinal cord. Also called spondylotic radiculomyelopathy (SRM), it is a neurological disorder related to the spinal cord and nerve roots. The severity of CSM is most commonly associated with factors including age, location and extent of spinal cord compression.