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Sacral Morel-Lavallee Lesions: A Not-So-Rare Diagnosis 2014

Category General Spine Jonathan Tresley, MD Sklar Evelyn, MD Jean Jose, DO Purpose A Morel-Lavallee lesion is a closed soft tissue degloving injury commonly occurring after a shearing trauma. The skin and subcutaneous tissues are separated from the underlying fascia and the new space is filled by serous fluid, liquefied blood, and necrotic tissue. Common sites include the soft tissues overlying bony protuberances, such as the patella, greater trochanter, and sacral region. Up to half of Morel-Lavalle lesions become infected. We present a patient whose clinical history was classic for the Morel-Lavallee lesion but whose imaging findings indicated a greater degree of hemorrhage than the prototypical Morel-Lavallee lesion. Materials & Methods Our patient is a 53 year old male who fell in the shower onto his lower back and subsequently noticed a soft tissue mass which would not resolve. The patient underwent contrast-enhanced MRI which revealed a large sacral Morel-Lavallee lesion. Due to persistent discomfort, the patient elected ultrasound-guided aspiration of the lesion. Results On physical exam, a large fluctuant soft tissue mass was noted. On MRI, within the subcutaneous tissues posterior to the sacrum, there was a non-enhancing, high T1 and T2 weighted, circumscribed, predominantly cystic structure measuring 12.5 cm x 5.8 cm x 18.7 cm (CC x AP x TRV). It contained nonenhancing low signal intensity septations and a non-enhancing posterior heterogeneous component measuring 6.8 cm x 1.4 cm x 13.6 cm. No invasion of the deep fascia or fractures were appreciated. Ultrasound revealed multiple septa without internal vascularity. 650 ml of hemorrhagic fluid was aspirated, and cultures were negative. At follow-up 3 weeks after the aspiration, the patient’s pain was nearly resolved and the mass had not reaccumulated. Conclusion Morel-Lavallee lesions are closed soft tissue degloving injuries that result from a shearing trauma over bony protuberances, most commonly the patella, greater trochanter, and sacrum. It is important to recognize this entity, its traumatic etiology, and its propensity to become infected in order to properly guide treatment, which often requires percutaneous drainage or open debridement. References Mukherjee, K., Perrin, S.M., and Hughes, P.M.. “Morel-Lavallee lesion in an adolescent with ultrasound and MRI correlation.” Skeletal Radiology (2007), 36, S43-S45. Hak, D.J., Olson, S.A., and Matta, J.M.. “Diagnosis and management of closed internal degloving injuries associated with pelvic and acetabular fractures: The Morel-Lavallee lesion.” The Journal of Trauma: Injury, Infection, and Critical Care (1997), 42(6), 1046-1051. Goodman, B.S., Smith, M.T., Mallempati, S., and Nuthakki, P.. “A comparison of ultrasound and magnetic resonance imaging findings of a morel-lavallee lesion of the knee.” Phyisical Medicine and Rehabilitation (2013). 5, 70-73. Tseng, S., and Tornetta IIII, P. “Percutaneous mangmenet of Morel-Lavallee lesions.” Journal of Bone and Joint Surgery (2006), 88A-1, 92-96.