What is the management and treatment for a patient with a Morel-Lavallee lesion?

Management of Morel-Lavallée Lesions

For Morel-Lavallée lesions, immediate operative management with open debridement is recommended when percutaneous aspiration yields more than 50 mL of fluid, as this predicts a high recurrence rate (83%) compared to lesions with smaller volumes (33% recurrence). 1

Initial Diagnosis and Assessment

Diagnostic imaging is essential for confirming the diagnosis:

• Ultrasound reveals a homogeneous, hypoechoic fluid collection between tissue planes 2, 3
• MRI demonstrates fluid of homogeneous signal intensity between the subcutaneous layer and underlying muscle fascia, confirming the closed degloving injury 2, 4
• Plain radiographs may show a round, radiopaque soft tissue lesion but are less specific 2

Key clinical features to identify:

• History of high-velocity trauma or significant shearing force to soft tissue, most commonly from motor vehicle collisions (25% of cases) 1, 4
• Painless, mobile, fluctuant soft tissue mass that may develop weeks to months after initial trauma 2, 5
• Most common locations are the greater trochanter, pelvis, and thigh, though proximal calf lesions can occur 2, 4

Treatment Algorithm Based on Lesion Characteristics

Volume-Based Decision Making:

If aspiration yields ≤50 mL of fluid:

• Percutaneous aspiration with compression wrapping is appropriate initial management 1
• Monitor for recurrence with serial examinations 1
• Resolution rate is 67% with conservative management in this group 1

If aspiration yields >50 mL of fluid:

• Proceed directly to operative management, as percutaneous aspiration has a 56% overall recurrence rate and 83% recurrence rate specifically in high-volume lesions 1
• This threshold should prompt immediate surgical intervention rather than repeated aspirations 1

Operative Management Technique

Surgical approach for chronic or recurrent lesions:

• Perform open debridement with radical excision of the pseudocapsule and necrotic tissue 2, 5
• Irrigate the cavity with 3% hypertonic saline combined with hydrogen peroxide to induce sclerosis and obliterate dead space 5
• Suture the superficial fascia to the deep fascia to prevent shearing at the surgical plane 2
• Apply continuous negative pressure suction with wound vacuum-assisted closure 1, 5
• Use compression bandaging postoperatively 1, 5

A critical pitfall is performing multiple repeated aspirations (5 or more attempts) before proceeding to definitive surgery, which prolongs morbidity and increases infection risk. 2, 3

Timing Considerations

Acute lesions (diagnosed within days to weeks of injury):

• May respond to conservative management with compression alone if small 4
• Early drainage/debridement prevents progression to chronic lesions and significantly shortens clinical course 3

Chronic lesions (diagnosed months after injury):

• Require surgical management due to high recurrence rates with conservative treatment 2, 4
• Delayed diagnosis increases risk of infection, especially if associated with fractures requiring operative fixation 4

Special Considerations in Polytrauma

In patients with associated fractures:

• Timely identification is crucial as progression of untreated Morel-Lavallée lesions poses infection risk at fracture sites 4
• Maintain high index of suspicion in severe blunt extremity injuries, as these lesions are frequently missed initially 3, 5
• MRI should be obtained when clinical suspicion exists despite initial diagnosis of simple contusion 3

The most common error is misdiagnosing Morel-Lavallée lesions as simple hematomas or muscle contusions, leading to delayed treatment and increased morbidity. 3, 5