What is a sequestrum in a horse?
A sequestrum is a piece of dead bone that has lost its blood supply. The horse’s body treats this as a foreign object, rather like a splinter, and the immune system tries to reject it. That is the reason for the heat, pain, swelling, discharge and failure to heal.
What is the cause of sequestrum?
There are three common causes to sequestrum formation; most commonly in cattle, a sequestrum is formed following a sharp trauma to the leg exposing the cortical bone and creating an ischemic zone that gets contaminated; a hematogenous septic microthrombus lodges in the cortical bone inducing ischemia; or it is formed …
What happens to sequestrum?
The sequestra are surrounded by sclerotic bone which is relatively avascular (without a blood supply). Within the bone itself, the haversian canals become blocked with scar tissue, and the bone becomes surrounded by thickened periosteum.
What are the types of sequestrum?
Types of sequestrum ️Tubular or diaphyseal sequestrum is seen in acute pyogenic osteomyelitis. ️Ring sequestrum is seen in amputation stump and at Steinmann pins. Ivory sequestrum is seen in syphilis. Fine sandy sequestrum is seen in viral osteomyelitis.
How do you treat sequestrum in horses?
Treatment of Bone Sequestrum in Horses Treatment of this condition typically consists of surgery to debride the affected area and remove the necrotic bone. Also, antibiotics should be prescribed to treat and prevent infection. Debridement of the wound should also be done.
Is sequestrum a radiopaque?
The history of trauma or infection combined with clinical appearance may be suggestive that radiography is required to determine location and extent of the sequestrum. The characteristic radiographic findings consist of a radiopaque dead bone surrounded by an area of lucent granulation tissue (involucrum).
How long does it take for a sequestrum to form?
A sequestrum is a devitalized, and typically infected, piece of bone that acts like a foreign body (think “splinter”) to prevent complete healing of the wound. These sequestra form when the blood supply to the bone is damaged or disrupted due to the initial wound, however often take 3-6 weeks to be identified.
What is sequestrum in horses?
A sequestrumis defined as “a piece of dead bone that has become separated from sound bone during the process of necrosis”. Bone sequestrae are fairly common occurrences in horses, especially in areas where the bone is not heavily protected by other tissues (such as muscle) and is particularly susceptible to external injury (such as a kick).
Is corneal ulceration a prerequisite for sequestrum formation in horses?
It appears that chronic, superficial corneal ulceration is a prerequisite for sequestrum formation in horses.
Why does a bone sequestrum delay healing?
A bone sequestrum can delay the healing process due to being a possible point of inflammation and infection. These can develop after injury or trauma. In some cases of an infected wound with a bone sequestrum, it will not heal until the sequestrum is removed; it will continue to drain since it will not be able to heal.
What does a radiograph of the sequestrum show?
A radiograph will show the sequestrum as a sclerotic segment of bone with a radiolucent zone surrounding it. It is recommended the image be taken 10 to 14 days after initial injury to see if there is a bone sequestrum developing or not.