Morel-Lavallee’ Lesion or Traumatic Hematoma after a Bicycle Accident-Introduction (Part 2)

I did a pretty exhaustive search on the internet concerning hematomas, specifically Morel Lavallee’ injuries, which describes my recent bicycle injury. As you may recall, I crashed during the Conquer the Coast Ride 2009. I wanted to share this entry on the internet to describe my story of this injury and gain a better understanding about this frustrating injury.

What is a Morel-Lavallee’ injury you may ask? Morel-Lavallee’ was a French physician who first described this injury in the 1800′s. They are also commonly called Morel-Lavallee’ lesions, because they can be of varying sizes and shapes.

Morel-Lavallée lesions or injuries are the result from a violent shear stress or shearing force to the anterolateral thigh where the skin and subcutaneous fatty tissue abruptly separates from the underlying fascia during a traumatic accident. [1] The traumatic lesion pattern has often been termed a “closed degloving injury”. Morel-Lavallée effusions are particularly common to the trochanteric region and proximal thigh, where they have been specifically referred to as Morel-Lavallée lesions. [2] In this region, the dermis contains a rich vascular plexus that pierces the fascia lata. [2] The disrupted capillaries may continuously drain into the perifascial plane, filling up the virtual cavity with blood, lymph, and debris. An inflammatory reaction commonly creates a peripheral capsule. These closed degloving injuries represent a traumatic severance of the skin and subcutaneous tissue from underlying fascia. The injury will disrupt segmental perforating vessels and result in a hematoma composed of hemolymphatic fluid with a mixture of blood, lymphatic fluid and necrotic fat. Depending on the violence of the injury, the resulting subcutaneous fluid collection may be either by slow accumulation of the lymphatics or develop a rapidly forming hematoma from trauma to arterial beds. Small lesions may resolve on their own or by simple incision, drainage, and application of a compression dressing. Persistent or larger lesions may contain a pseudocapsule that makes them refractory to conservative treatment and almost always require surgical decompression.

This injury typically involves the tensor fascia lata and illiotibial band. Again, the seperation of the tensor fascia away from the overlying subcutaneous fat can cause an acute arterial hematoma in a closed “degloving” fashion. This seperation can cause blood and other fluids to travel and dissect along the fascial plane all the way to the knee along the illiotibial band. The term illiotibial band syndrome describes pain along the lateral femoral epicondyle, which is caused by inflammation resulting from friction as iliotibial tract slides over the condylar prominence. I’ll talk about this more later as a secondary complication of this injury.

I found very little reports of this type of injury after a bicycle accident, although I’m sure it has happened. Most of the case reports floating around the internet describe these injuries associated with motor vehicle accidents and hip fractures.

Here are some photos of Morel-Lavallee’ lesions taken directly off the internet:

More on the aftermath of the initial accident in Part 3

---

References
1. Bruce Curtiss Gilbert, Liem T. Bui-Mansfield and Schuyler Dejong: MRI of a Morel-Lavallée Lesion. American Journal of Roentology, 2004; 182:1347-1348. [online]
2. J. M. Mellado, L. Pérez del Palomar, L. Díaz, A. Ramos and A. Saurí: Long-Standing Morel-Lavallée Lesions of the Trochanteric Region and Proximal Thigh: MRI Features in Five Patients. American Journal of Roentology 2004; 182:1289-1294. [online]

The Series
Part 1 – Anatomy of a Bicycle Crash
Part 2 – Morel-Lavallee’ Lesion or Traumatic Hematoma after a Bicyle Accident
Part 3 – Morel-Lavalle’ Lesion – The Aftermath
Part 4 – Morel-Lavalle’ Lesion – The Surgery

Fini-MLL 1 year later

Advertisement