What is Degloving Injuries?
Internal degloving injuries typically come from intense trauma and can cause severe harm. These injuries are also known as Morel-Lavallee lesions, especially when they occur in the pelvic or thigh area. A degloving happens when the top layer of connective tissue, or fascia, comes apart from the deeper layer due to a shearing or tearing action. This not only stops the flow of blood and lymph fluid through the channels between these two layers but also forms a space that can fill with fluid. The mix of blood and lymph fluid that gathers can lead to infections and might also threaten the health of the overlying skin, putting it at risk of death or necrosis. The way to handle such injuries depends on the size of the lesion, how severe it is, and what other injuries are present.
What Causes Degloving Injuries?
Internal degloving injuries are rare but can have serious health impacts, especially if they are overlooked. They are more common in males. These types of injuries often occur due to high-speed motor vehicle crashes, motorcycle accidents, or direct impact to the area. Among these, car accidents are the most frequently reported cause.
Such injuries can happen anywhere in the body, but 93% of the time, they are found around the hip or lower body areas. Breakdown of these injuries by location looks like this: hip (30%), thigh (20%), pelvis (19%), knee (16%), buttocks (6%), lower back (3%), abdominal area (1%), calf or lower leg (2%), and head (0.5%).
Risk Factors and Frequency for Degloving Injuries
Internal degloving injuries are difficult to count accurately because minor injuries that result in small fluid collections might not be significant enough to notice. Also, large internal injuries are often overlooked because they may appear later or be overshadowed by other injuries. These injuries usually do not happen on their own. They are often found along with Morel-Lavallee lesions and can complicate the treatment of fractures in the pelvis, hip socket or upper thigh. There is a wide range of rates at which they accompany pelvic or hip socket fractures and Morel-Lavallee lesions.
Signs and Symptoms of Degloving Injuries
Internal degloving injuries are serious conditions that can occur immediately after trauma or develop over time. The signs of these injuries may not be clear right away, especially in people with multiple injuries, or a significantly high body mass index (BMI). This means that about 33% of the time, these injuries are overlooked.
It’s important for medical practitioners to look for specific signs on the skin in regions where an internal degloving injury might have happened. These signs could include:
- Bruising or discoloration, known as ecchymosis
- Swelling or puffiness, known as edema
- Feeling of liquid under the skin, known as fluctuance
- Loose or movable skin
- Decreased skin sensation
As time goes on, the injured area might get bigger, and the skin over it can become firm and painful. This is a sign that the fluid collection underneath is becoming encapsulated or trapped.
Testing for Degloving Injuries
If a doctor suspects a certain condition based on a patient’s symptoms, they may use a large needle to extract a sample from the affected area. This helps them in making a diagnosis. They may also use techniques like ultrasound, CT scans, and MRI scans.
An ultrasound can show the issue as an area of varying shades of grey, with or without different fluid levels, located closer to the surface than the deep connecting tissue. If a patient is already having a CT or MRI scan for another reason, such as investigating an injury, this could serve multiple purposes and help identify the issue as well. However, MRI scans are often the most effective in diagnosing this specific type of injury.
In an MRI, fresh injuries appear darker in T1-weighted images and brighter in T2-weighted images. In older injuries, the issue appears bright in both T1- and T2-weighted images, and the outer protective layer appears dark in both.
Experts Mellado and Bencardino have identified six types of these injuries based on varying factors such as how old the injury is, the size and shape of the fluid build-up, and patterns observed in MRI imaging. These injuries can present as a simple fluid-filled pocket to more severe, chronic, complicated, or infected fluid collections. This classification allows better management because it guides the treatment approach depending on how the condition presents itself.
Treatment Options for Degloving Injuries
Treating internal degloving injuries is a complex process, and the best approach depends on factors like the patient’s overall health, the presence of broken bones, and the planned surgical approach. It’s also crucial to carefully assess the damaged and potentially at-risk tissue, including the initial health of the skin and the size of the fluid-filled cavity. The injury may be managed in different ways, including compression therapy, needle drainage, medication to harden the tissue, and basic or elaborate surgical cleaning and removal of dead tissue.
A few studies have shown that non-surgical management, such as using a compression wrap and occasionally draining the fluid with a needle, can work in certain cases. This conservative approach is usually reserved for small injuries (less than 50 mL) without severe symptoms and with healthy overlying skin. If these injuries don’t improve with compression and drainage, other agents like talc, ethanol, or doxycycline can be used to harden the tissue. However, as the size of the injury increases, the likelihood of non-surgical treatment being successful decreases. Therefore, if a fluid-filled cavity in an internal degloving injury is over 50 mL, surgical intervention is generally recommended.
Several studies have reported better outcomes with surgery compared to conservative treatments for these injuries. In fact, standard care for larger injuries, especially with skin necrosis, is to make an incision and drain the fluid. Some researchers have suggested a more aggressive surgical approach. This includes making an incision in the middle of the degloved area, taking samples for culture, draining and cleaning the wound aggressively, and removing any dead fatty and connective tissue before leaving the wounds open and packed with sterile gauze. Regardless of the approach chosen, it’s crucial to remember that no single surgical technique has been proven as the best one.
The decision to sew the wound back up is up to the particular surgeon, and negative pressure dressings, which help suck fluid and infection out of the wound, can be helpful with sealing the wound and preparing it for a graft if needed. Ultimately, successful treatment relies heavily on carefully assessing each patient’s situation and choosing the most appropriate treatment approach.
What else can Degloving Injuries be?
Some conditions that could be mistaken for internal degloving injuries (where the skin is torn away from the tissue underneath) include:
- Seroma (a pocket of clear bodily fluid)
- Abscess (a pocket of pus)
- Vascular injury (damage to the blood vessels)
- Compartment syndrome (increased pressure in a muscle compartment)
- Deep venous thrombosis (a blood clot in the deep veins)
But, with a proper medical history, a physical exam, and the right imaging tests, doctors should be able to identify the correct condition.
It’s less likely for someone to have a seroma or abscess right after an injury. To rule out vascular injury, doctors may check the blood flow and nerves in the extremities, measure blood pressure at the ankle and the arm (ankle-brachial index), or request a CT angiogram if needed.
Deep venous thrombosis would usually cause more general swelling in the limb, and this can be checked with a duplex ultrasound (a type of ultrasound that can show how blood flows to many arteries and veins in the body).
Compartment syndrome, which is a serious condition that involves increased pressure in a muscle compartment, can cause severe tissue damage. It’s not common in the thigh and could be ruled out through a physical exam, though pressure measurements might be taken if it’s still a possibility.
What to expect with Degloving Injuries
The existing research shows that with correct identification and appropriate surgical treatment of Morel-Lavallee lesions, complete recovery is possible. However, complications such as recurrence, infection, and wound healing problems are common.
Possible Complications When Diagnosed with Degloving Injuries
The most common issue after a degloving injury, such as a Morel-Lavallee lesion, is recurrence, which is the re-occurrence of fluid collection. The chances of recurrence vary depending on the treatment method used. Out of all the treatments, percutaneous aspiration, a procedure for removing fluid, has the highest rate of recurrence at around 56%. This is compared to compression wrapping and observation which has a recurrence rate of 19%. Lower recurrence rates are usually seen when the injury is managed correctly with surgery. It’s also more likely for the condition to reoccur if the lesions are larger. However, where the injury is on the body doesn’t impact the recurrence rate.
If the fluid collection comes back after treatment, there are several options to manage it. These include:
- Repeated surgical drainage
- Percutaneous drain placement
- Negative pressure wound therapy
- Sclerotherapy
In case of a large chronic lesion needing surgical treatment, it is important to ensure removal of the dead space and complete excision of the pseudocapsule, a layer that forms around the lesion.
Skin necrosis, or the death of skin cells, is another possible complication. The likelihood of this happening increases if there is a delay in finding and treating the lesion, or if the lesion is large. In such cases, a plastic surgery referral might be needed for wound coverage, tissue repositioning and managing any visual concerns.
Bacterial accumulation is quite common in Morel-Lavallee lesions, and can lead to more serious issues such as infection or necrotizing fasciitis, a severe infection resulting in tissue death. It is recommended to quickly remove any untreated lesions to avoid these complications. In fact, one study reported a high early infection rate of 56%, and another found 25% of their patients developed an infection. To combat this issue and prevent infection, it’s advised to use antibiotics as long as any drain is present.
Morel-Lavallee lesions can complicate the treatment of bone-related injuries. A certain study found an 8.4 times higher risk of post-surgical infection after fixing a broken hip socket if a Morel-Lavallee lesion is present.
Preventing Degloving Injuries
Patients who have experienced internal degloving injuries often have other injuries, including orthopedic ones at the time they first seek medical help. It’s crucial to have conversations with such patients and their families about what they can expect during their healing process. They should be told that an internal degloving injury, which is not very common, might complicate any broken bones in the affected area. However, they should be reassured that surgical treatment is often successful, with the aim being a full recovery.