Avulsion injury
Encyclopedia
In medicine
, an avulsion is an injury in which a body structure is forcibly detached. It most commonly refers to a surface trauma where all layers of the skin
have been torn away, exposing the underlying structures (e.g. subcutaneous tissue
, muscle
, tendons). This is similar to an abrasion but more severe, as body parts such as an eyelid or an ear can be partially or fully detached from the body. The term comes from the Latin word avellere, "to tear off".
and skin grafts.
avulsions are repaired by suturing after a CT scan
is performed to determine where damage to the muscles, nerves, and blood vessels of the eyelid has occurred. More severe injuries require reconstruction, however, this usually results in some loss of function and subsequent surgeries may be necessary to improve structure and function. Microvascular surgery is another method of repair but used rarely. Sometimes botulinum toxin is injected into the eyelid to paralyse the muscles while the eyelid heals.
can cause the nail plate to be torn from the nail bed. Unlike other types of avulsion, when a nail is lost, it is not reattached. Following the loss of the nail, the nail bed forms a germinal layer which hardens as the cells acquire keratin
and becomes a new nail. Until this layer has formed, the exposed nail bed is highly sensitive and should be covered with a non-adherent dressing
, as an ordinary dressing will stick to the nail bed and cause extreme pain upon removal. In the average person, fingernails require 3 to 6 months to regrow completely, while toenails require 12 to 18 months.
(a bundle of nerves that sends signals from the spine to the arms, shoulders, and hands) is torn from its attachment to the spine
. One common cause of this injury is when a baby's shoulders rotate in the birth canal during delivery and cause the brachial plexus to stretch and tear. It occurs in 1-2 out of every 1,000 births. Shoulder trauma during motor vehicle accidents is another common cause. Detachment of the nerves causes pain and loss of function in the arms, shoulders, and hands. Neuropathic pain
can be treated with medication, but function can only be restored through surgical reattachment or nerve grafts. For intractable pain, a procedure called dorsal root entry zone (DREZ) lesioning is effective.
(moderate) and amputation
of a finger or limb (severe). Suprafascial avulsions are those in which the depth of the removed skin reaches the subcutaneous tissue
layer. Subfascial avulsions are those deeper than the subcutaneous layer. Small suprafascial avulsions can be repaired by suturing, but most avulsions require skin grafts or reconstructive surgery.
, a flapper is an injury in which parts of the skin are torn off, resulting in a loose flap of skin on the fingers. This is usually the result of friction forces between the climber's fingers and the holds
, arising when the climber slips off a hold.
makes replacement of the tooth impossible. To minimise damage to the root, the tooth should be kept in milk or sterile saline
while it is outside the mouth.
) is used to remove varicose veins from the legs in disorders such as Chronic venous insufficiency
. A nail avulsion is performed to remove all or part of a chronic ingrown nail
. Facial nerve
avulsion is used to treat the involuntary twitching in Benign Essential Blepharospasm
. However, it often requires additional surgeries to retain function and botulinum toxin injections have proved to be a more effective treatment with fewer complications.
. Sometimes after a traumatic injury, the periosteum can peel off the bone's surface. An example of such an injury would be an ALPSA
(anterior labral periosteal sleeve avulsion).
Medicine
Medicine is the science and art of healing. It encompasses a variety of health care practices evolved to maintain and restore health by the prevention and treatment of illness....
, an avulsion is an injury in which a body structure is forcibly detached. It most commonly refers to a surface trauma where all layers of the skin
Skin
-Dermis:The dermis is the layer of skin beneath the epidermis that consists of connective tissue and cushions the body from stress and strain. The dermis is tightly connected to the epidermis by a basement membrane. It also harbors many Mechanoreceptors that provide the sense of touch and heat...
have been torn away, exposing the underlying structures (e.g. subcutaneous tissue
Subcutaneous tissue
The hypodermis, also called the hypoderm, subcutaneous tissue, or superficial fascia is the lowermost layer of the integumentary system in vertebrates. Types of cells that are found in the hypodermis are fibroblasts, adipose cells, and macrophages...
, muscle
Muscle
Muscle is a contractile tissue of animals and is derived from the mesodermal layer of embryonic germ cells. Muscle cells contain contractile filaments that move past each other and change the size of the cell. They are classified as skeletal, cardiac, or smooth muscles. Their function is to...
, tendons). This is similar to an abrasion but more severe, as body parts such as an eyelid or an ear can be partially or fully detached from the body. The term comes from the Latin word avellere, "to tear off".
Types of avulsions
- Ear
- Eyelid
- Nail
- Nerve (brachial plexus)
- Skin
- Tooth
- Surgical
- Periosteal
Ear avulsions
The ear is particularly vulnerable to avulsion injuries because of its exposed position on the side of the head. The most common cause of these injuries is human bites, followed by falls, motor vehicle accidents, and dog bites. A partially avulsed ear can be reattached through suturing or microvascular surgery, depending on the severity of the injury. Microvascular surgery can also be used to reattach a completely avulsed ear, but its success rate is lower because of the need for venous drainage. The ear can also be reconstructed with cartilageCartilage
Cartilage is a flexible connective tissue found in many areas in the bodies of humans and other animals, including the joints between bones, the rib cage, the ear, the nose, the elbow, the knee, the ankle, the bronchial tubes and the intervertebral discs...
and skin grafts.
Eyelid avulsions
This is an uncommon injury that can be caused by motor vehicle accidents, dog bites, or human bites. EyelidEyelid
An eyelid is a thin fold of skin that covers and protects an eye. With the exception of the prepuce and the labia minora, it has the thinnest skin of the whole body. The levator palpebrae superioris muscle retracts the eyelid to "open" the eye. This can be either voluntarily or involuntarily...
avulsions are repaired by suturing after a CT scan
Computed tomography
X-ray computed tomography or Computer tomography , is a medical imaging method employing tomography created by computer processing...
is performed to determine where damage to the muscles, nerves, and blood vessels of the eyelid has occurred. More severe injuries require reconstruction, however, this usually results in some loss of function and subsequent surgeries may be necessary to improve structure and function. Microvascular surgery is another method of repair but used rarely. Sometimes botulinum toxin is injected into the eyelid to paralyse the muscles while the eyelid heals.
Traumatic nail avulsions
Trauma to the nailNail (anatomy)
A nail is a horn-like envelope covering the dorsal aspect of the terminal phalanges of fingers and toes in humans, most non-human primates, and a few other mammals. Nails are similar to claws, which are found on numerous other animals....
can cause the nail plate to be torn from the nail bed. Unlike other types of avulsion, when a nail is lost, it is not reattached. Following the loss of the nail, the nail bed forms a germinal layer which hardens as the cells acquire keratin
Keratin
Keratin refers to a family of fibrous structural proteins. Keratin is the key of structural material making up the outer layer of human skin. It is also the key structural component of hair and nails...
and becomes a new nail. Until this layer has formed, the exposed nail bed is highly sensitive and should be covered with a non-adherent dressing
Dressing (medical)
A dressing is an adjunct used by a person for application to a wound to promote healing and/or prevent further harm. A dressing is designed to be in direct contact with the wound, which makes it different from a bandage, which is primarily used to hold a dressing in place...
, as an ordinary dressing will stick to the nail bed and cause extreme pain upon removal. In the average person, fingernails require 3 to 6 months to regrow completely, while toenails require 12 to 18 months.
Brachial plexus avulsions
In this type of injury, the brachial plexusBrachial plexus
The brachial plexus is a network of nerve fibers, running from the spine, formed by the ventral rami of the lower four cervical and first thoracic nerve roots...
(a bundle of nerves that sends signals from the spine to the arms, shoulders, and hands) is torn from its attachment to the spine
Spinal cord
The spinal cord is a long, thin, tubular bundle of nervous tissue and support cells that extends from the brain . The brain and spinal cord together make up the central nervous system...
. One common cause of this injury is when a baby's shoulders rotate in the birth canal during delivery and cause the brachial plexus to stretch and tear. It occurs in 1-2 out of every 1,000 births. Shoulder trauma during motor vehicle accidents is another common cause. Detachment of the nerves causes pain and loss of function in the arms, shoulders, and hands. Neuropathic pain
Neuropathic pain
Neuropathic pain results from lesions or diseases affecting the somatosensory system. It may be associated with abnormal sensations called dysesthesia, which occur spontaneously and allodynia that occurs in response to external stimuli. Neuropathic pain may have continuous and/or episodic ...
can be treated with medication, but function can only be restored through surgical reattachment or nerve grafts. For intractable pain, a procedure called dorsal root entry zone (DREZ) lesioning is effective.
Skin avulsions
The most common avulsion injury, skin avulsions usually occur during motor vehicle accidents. The severity ranges from skin flaps (minor) to deglovingDegloving
A degloving injury is a type of avulsion in which an extensive section of skin is completely torn off the underlying tissue, severing its blood supply. It is named by analogy to the process of removing a glove....
(moderate) and amputation
Amputation
Amputation is the removal of a body extremity by trauma, prolonged constriction, or surgery. As a surgical measure, it is used to control pain or a disease process in the affected limb, such as malignancy or gangrene. In some cases, it is carried out on individuals as a preventative surgery for...
of a finger or limb (severe). Suprafascial avulsions are those in which the depth of the removed skin reaches the subcutaneous tissue
Subcutaneous tissue
The hypodermis, also called the hypoderm, subcutaneous tissue, or superficial fascia is the lowermost layer of the integumentary system in vertebrates. Types of cells that are found in the hypodermis are fibroblasts, adipose cells, and macrophages...
layer. Subfascial avulsions are those deeper than the subcutaneous layer. Small suprafascial avulsions can be repaired by suturing, but most avulsions require skin grafts or reconstructive surgery.
Rock climbing
In rock climbingRock climbing
Rock climbing also lightly called 'The Gravity Game', is a sport in which participants climb up, down or across natural rock formations or artificial rock walls. The goal is to reach the summit of a formation or the endpoint of a pre-defined route without falling...
, a flapper is an injury in which parts of the skin are torn off, resulting in a loose flap of skin on the fingers. This is usually the result of friction forces between the climber's fingers and the holds
Climbing hold
A climbing hold is a shaped grip that is usually attached to a climbing wall so climbers can grab or step on it. On most walls, climbing holds are arranged in paths, called routes, by specially trained route setters. Climbing holds come in a large array of sizes and shapes to provide different...
, arising when the climber slips off a hold.
Tooth avulsions
A tooth completely or partially (such that the dental pulp is exposed) detached from its socket is avulsed. Secondary (permanent) teeth can be replaced and stabilised by a dentist. Primary (baby) teeth are not replaced because they tend to become infected and to interfere with the growth of the secondary teeth. A completely avulsed tooth that is replaced within one hour of the injury can be permanently retained. The long-term retention rate decreases as the time that the tooth is detached increases, and eventually root resorptionRoot resorption
In dentistry, root resorption is the breakdown or destruction, and subsequent loss, of the root structure of a tooth. This is caused by living body cells attacking part of the tooth. When the damage extends to the whole tooth, it is called tooth resorption...
makes replacement of the tooth impossible. To minimise damage to the root, the tooth should be kept in milk or sterile saline
Saline (medicine)
In medicine, saline is a general term referring to a sterile solution of sodium chloride in water but is only sterile when it is to be placed intravenously, otherwise, a saline solution is a salt water solution...
while it is outside the mouth.
Surgical avulsions
An avulsion is sometimes performed surgically to relieve symptoms of a disorder or prevent a chronic condition from recurring. Small incision avulsion (also called ambulatory phlebectomyAmbulatory phlebectomy
Ambulatory phlebectomy is a treatment for superficial varicose veins. The procedure involves the removal of the varicose veins through small 2–3 mm incisions in the skin overlying the veins. The procedure may be performed in hospital or outpatient settings...
) is used to remove varicose veins from the legs in disorders such as Chronic venous insufficiency
Chronic venous insufficiency
Chronic venous insufficiency or CVI is a medical condition where the veins cannot pump enough oxygen-poor blood back to the heart. It is sometimes referred to as an "impaired musculovenous pump", this is due to damaged or "incompetent" valves as may occur after deep vein thrombosis or phlebitis...
. A nail avulsion is performed to remove all or part of a chronic ingrown nail
Ingrown nail
Onychocryptosis , also known as an ingrown toenail, or unguis incarnatus is a common form of nail disease. It is an often painful condition in which the nail grows so that it cuts into one or both sides of the paronychium or nail bed...
. Facial nerve
Facial nerve
The facial nerve is the seventh of twelve paired cranial nerves. It emerges from the brainstem between the pons and the medulla, and controls the muscles of facial expression, and functions in the conveyance of taste sensations from the anterior two-thirds of the tongue and oral cavity...
avulsion is used to treat the involuntary twitching in Benign Essential Blepharospasm
Blepharospasm
A blepharospasm , is any abnormal contraction or twitch of the eyelid....
. However, it often requires additional surgeries to retain function and botulinum toxin injections have proved to be a more effective treatment with fewer complications.
Periosteal avulsions
The bone is sorrounded by a fibrous layer called the periosteumPeriosteum
Periosteum is a membrane that lines the outer surface of all bones, except at the joints of long bones. Endosteum lines the inner surface of all bones....
. Sometimes after a traumatic injury, the periosteum can peel off the bone's surface. An example of such an injury would be an ALPSA
Alpsa lesion
An ALPSA lesion is an injury at the front of the shoulder associated with shoulder dislocation.-Anatomy:...
(anterior labral periosteal sleeve avulsion).