Morel Lavallee lesions in orthopedics
A Morel Lavallee lesion is a post-traumatic soft tissue degloving injury, originally described by French surgeon Victor Auguste Francois Morel-Lavallee in 1863. These lesions result from direct or tangential shearing forces that separate the skin and subcutaneous tissues from the underlying fascia. These shearing forces can disrupt perforating vessels and nerves, creating a potential space that fills with blood, lymph, debris, and fat (necrotic and/or viable). This can also cause abrasions or friction burns.
Delayed diagnosis or delayed treatment can lead to
" Even if there is no direct injury to skin the hematoma due to pressure or the hemoglobin released has strong affinity to oxygen causes intense hypoxia and ischemia of skin leading to necrosis"
Closed degloving injuries are most commonly found adjacent to osseous protuberances, and have been described along the greater trochanter, flank, buttock, lumbar spine, scapula, and knee.
Natural history of Morel Lavallee lesions
In a setting of high-energy injury, the relatively mobile skin and subcutaneous tissues are torn away from the less yielding aponeurotic fascia by a crushing and shearing force,resulting in blood and lymphatic vessel disruption.Thus, a potential space is created that may fill with blood, lymph, and necrotic fat. Based on this process, the resultant subcutaneous fluid collection may lead to various lesions, such as seroma, subacute hematoma, or chronic organizing hematoma. As the effusion evolves, the blood is largely resorbed and replaced by serosanguinous fluid. The final step in the evolution of MLLs is creation of a peripheral capsule around the lesion as a result of an anti-inflammatory reaction, which may account for the permanence of the fluid mass. Although the swelling may continue to enlarge gradually-possibly caused by increased osmotic pressure in the cyst from the chronic infammatory process, repeat trauma, bleeding from friable capillaries.
Clinical features of Morel Lavallee lesions
The clinical features of MLL vary depending on the amount of blood and lymphatic fluid collected at the site of injury and on the time elapsed since the injury. A soft fluctuant area with hypermobile skin is a typical finding on physical examination. Bruising, ecchymosis, laceration, and/or contusion may be found. MLLs may manifest as skin necrosis, which has been reported to occur as a result of direct trauma to the cutaneous layers but may also occur on a delayed basis secondary to swelling of the degloved cavity, resulting in ischemia of the overlying skin. Although MLLs are closed injuries, previous reports have documented their potential to be colonized with bacteria. The skin over a MLL remains intact, thus, the infection of the cyst is due to bacterial translocation from the central circulation. Local wound sepsis and life-threatening sepsis accompanying MLL have been described.
Plain radiography may reveal a noncalcified soft tissue mass and associated fractures. The sonographic appearance is nonspecific and variable, with lesions described as anechoic, hypoechoic and hyperechoic. Hyperechoic nodules of internal fat may be seen on ultrasound. CT can show fluid-fluid levels related to sedimentation of the hemolymphatic fluid, varying amounts of internal debris including internal fat lobules, and may show a peripheral capsule.
MRI is the imaging modality of choice in the evaluation of Morel Lavallee lesions. Morel-Lavalee lesions are well defined oval, fusiform, or crescentic and may have tapering margins that fuse with adjacent fascial planes. Morel-Lavallee lesions may show fluid-fluid levels, septations, and variable internal signal intensity dependent on the concentration of hemolymphatic fluid and the acuity of the lesion. Lesions may have no capsule, a partial capsule, or complete capsule. Capsules are hypointense on all pulse sequences related to fibrous tissue and/or blood-by-products. Lesions can have no enhancement, peripheral, septal, or internal enhancement.
Mellado and Bencardino proposed an MRI classification system of Morel Lavallee lesions based on lesion shape, signal and enhancement characteristics, and presence or absence of a capsule.
Although various strategies for the treatment of MLL have been reported, including the application of compression bandages, percutaneous aspiration and drainage, open debridement and sclerodhesis, there are no established treatment modalities for patients with MLL. Conservative management such as compression bandage application, NSAID medication, physiotherapy and absolute bed rest are considered the first-line treatment regimen in patients with acute, small lesions without underlying fractures. Of these, the compression bandage can be used to supplement other treatment options.
" Type 1 and 4 lesion Simple aspiration with needle will not suffice if collection >50ml use closed suction drain "
Percutaneous drainage can be used to manage larger acute lesions that cannot be resolved with a single application of compression bandages. It may also be attempted along with sclerotherapy as a first-line therapy in patients with chronic lesions. Various methods of sclerodhesis, including some that involve the use of alcohol and doxycycline, have been reported. Sclerotherapy is performed by injection of sclerosant into the dead space; the sclerosant is allowed to remain for a few minutes, followed by percutaneous drainage. Sclerotherapy can be used as a first-line therapy in patients with acute lesions that are refractory to compression bandages and in patients with chronic lesions. In patients with chronic lesions, percutaneous drainage may result in recurrent postoperative hematoma or secondary infection. It is therefore mandatory to combine percutaneous drainage with sclerotherapy.
“Type 2 lesions Sclerotherapy with Doxycyline 600mg dissolved in 50ml saline and 10ml lignocaine 1% injected into cavity after aspiration and place continuous drainage tube”
There is no consensus about the surgical indications or the proper timing of the surgery. Its recommended early, thorough debridement because development of a hematoma in the zone of the operation could reduce the safety of any early operative intervention by increasing the risk of infection and compromising the skin’s vascularity. When the overlying skin and soft tissue has partial- to full-thickness abrasions or areas of skin necrosis, debridement should be performed at a separate operative setting, before formal open reduction of the pelvic ring or acetabular fracture. When the skin and soft tissue envelope are intact, debridement of the degloved area can be performed during the same procedure as the open reduction and internal fixation. The wound should be left open and repeated surgical debridement undertaken, allowing it to heal by secondary intention.
The lesions can be completely evacuated through incisions at their proximal and distal extents followed by irrigation and suction drainage. Percutaneous fixation of the posterior part of the pelvic ring may undertaken subsequent to treatment of the MLL but during the same operative setting. Open fixation of pelvic fractures and acetabular fractures is deferred until at least 24 hours after the drains are removed. Percutaneous procedures for pelvic fixation in the same operative setting are usually well tolerated, and open procedures appear to be safe when performed in a delayed fashion.
Various management techniques have been proposed based on the consensus of treating MLL with open surgery, which involves evacuating the hemolymphatic collection by excising the pseudocapsule and debriding necrotic tissue. Several authors advocated the use of vacuum dressings and wound closed by secondary closure or split-skin coverage. Fibrin sealant spray and resorbable quilting sutures after surgical debridement have been successfully employed to eliminate any potential space, thereby reducing the chance of recurrence.
" All Type 3 and 5 lesions require operative surgery with excision of capsule and obliteration of cavity with quilting sutures or fibrin sealant"
"Type 6 lesion require operative management with debridement and secondary healing or delayed grafting"
Management of Overlaying skin
"Never assume wait and watch attitude you should control the wound"
"In cases where the skin is thin and completely devascularized following drainage of hematoma then completely de fat the skin and make fenestrations and place over raw area as full thickness graft and apply negative pressure wound therapy, alternatively harvest split skin graft from flap and graft the wound "
The difficulty in management of Morel-Lavallee lesion is in predicting skin viability. Fluorescein is a fluorescent dye used in flow cytometry, which has been used experimentally to assess tissue viability. It is administered intravenously upon flap elevation, and the fluorescence is subjectively measured with the aid of ultraviolet light approximately 10 to 15 minutes postadministration. Viable skin appears bright yellowish green; flaps that are blue and nonfluorescent are not viable. Skin with spotty areas of fluorescence lies somewhere in between. In one study, the fluorescein test was extremely reliable even when it contradicted traditional clinical signs of viability such as capillary refill and flap color. Fluorescein is relatively safe; side effects include nausea and vomiting. The manufacturers have found no reports of death related to its use. Despite the study's success, fluorescein has not been widely studied for this application. With further investigation, this may be a valuable asset to the physician faced with assessing skin viability of a Morel-Lavallee lesion.
" Use a cost effective and simple technique of fluorescent dye injection and observation of skin flap with Woods lamp intraopratively any Areas of nonfluorescence <4 cm2 typically survive and >4cm2 may be debrided"
Have a high index of suspicions in cases which present with swelling or eccymosis and abrasion of skin. MRI is the ideal diagnostic modality. Always drain the underlying hematoma. Early management of skin can help in early bone intervention and early recovery.