Chronic Morel-Lavallée Lesion: A Novel Minimally Invasive Method of Treatment

Morel-Lavallée lesions tend to be misdiagnosed when patients present with soft tissue injury alone and are treated in an outpatient department. A 35-year-old woman presented with swelling over the posterolateral aspect of the thigh 3 months after sustaining an injury. Diagnosis of Morel-Lavallée lesion was made and confirmed by ultrasound examination. The  walls of the lesion were debrided using an arthroscopic shaver (Stryker, Kalamazoo, MI), and intermittent suction therapy was applied to obliterate the dead space. This brief report demonstrates that this minimally invasive technique is effective in treating chronic Morel-Lavallée lesions.

A Morel-Lavallée lesion is a closed internal degloving injury resulting from a shearing force applied to the skin. The etiology of this condition may be motor vehicle accidents, falls, contact sports (ie, football, wrestling),¹ and iatrogenic after mammoplasty or abdominal liposuction.² Common sites of the lesions include the pelvis and/or thigh.³ Isolated Morel-Lavallée lesions without underlying fracture are likely to be missed, which result in chronicity. Management of this condition often requires extensive surgical procedures such as debridement, sclerotherapy, serial percutaneous drainage, negative pressure wound therapy (NPWT), and skin grafting.^4,5 The authors wish to highlight a minimally invasive technique for the treatment of chronic Morel-Lavallée lesions.

A 35-year-old woman presented to the emergency department with swelling over her right thigh 3 months after sustaining an injury in a motor vehicle accident. At the emergency department, radiographic films were taken and showed no fracture. She was discharged with directions to apply cold compress and use analgesics. Over a period of 2–3 weeks, she developed swelling over the right thigh, which progressively increased in size. This swelling was asymptomatic throughout the course of the condition’s development. She expected the swelling would resolve in time, but she eventually presented to the outpatient department after 12 weeks of no change when the condition failed to resolve. Examination revealed fluctuant swelling on the posterolateral aspect of her right thigh (Figure 1). The dimensions of the swelling were approximately 23 cm x 7.5 cm, and the swelling was nontender and showed no inflammatory signs. 

Investigations
Radiographic films of the pelvis and right thigh revealed no bony injury. A high resolution ultrasound scan showed a fluid-filled space approximately 25 cm x 9 cm x 1.7 cm in the subcutaneous plane superficial to the deep fascia. The cavity was surrounded by a pseudocapsule. Magnetic resonance imaging, the gold standard for diagnosing Morel-Lavallée lesion, was not performed due to clear-cut findings on the ultrasound.⁶ Routine hematology and inflammatory markers were negative. 

Differential diagnosis
Initially, the authors suspected a chronic abscess but hematology and inflammatory marker tests (ie, erythrocyte sedimentation rate, C-reactive protein) ruled out an infective pathology. Based on the clinical and ultrasound findings, the lesion was diagnosed as chronic Morel-Lavallée lesion.

Treatment
The patient was reluctant to undergo an extensive open procedure. Thus, the authors chose a minimally invasive approach for removal of the pseudocapusle and obliteration of dead space. An arthroscopic shaver (Stryker formula 4 mm, Stryker, Kalamazoo, MI) was used to debride the pseudocapsule (Figure 2A). Intra-operative imaging was not considered because the lesion was superficial and easily accessible. In the operating room under sterile conditions, the skin overlying the swelling was anesthetised with 1% lidocaine. A stab incision was made to give the shaver tip access to debride the pseudocapsule. The shaver was connected to a suction apparatus, which allowed drainage of clear, watery, straw-colored fluid. The shaver blade was set to reciprocating mode at a speed of 1800 rpm and was introduced into the cavity. The pseudocapsule over the base of the lesion was first debrided, and the surface of the skin was supported by the palm of the hand while debriding the roof in order to prevent undue stretching of the skin that would lead to loss of vascularity.  This step is essential, because vascularity of the overlying skin needs to be preserved in order to promote wound healing. Due to the length of the lesion, the shaver tip was passed through another stab incision in the distal part to access the entire cavity (Figure 2B). Intermittent suction therapy was applied to a perforated FG-14 catheter passed along the length of the lesion. The catheter was connected to a NPWT machine for 6 days. The authors utilized a generic suction device and timer switch that produced a negative pressure ranging from 125 mm Hg to 150 mm Hg, 5 minutes on and 3 minutes off.⁷ During the course of treatment, the patient was given prophylactic antibiotic therapy. When fluid collection subsided to < 10 mL/day, the suction catheter was removed and a pressure garment was applied over the afflicted thigh. 

Outcome and follow-up
Reduction of dead space was achieved within 3 weeks, by which time the pressure garment was discontinued (Figure 3). The authors followed up with the patient for 6 months without recurrence of the condition. 

Morel-Lavallée lesions are shearing injuries resulting in separation of skin and subcutaneous tissue from the deep fascia. Common sites are around the pelvis, thigh, and knee joint and over the scapula in decreasing order of frequency.⁸ They are usually associated with an underlying fracture. The present patient presented late because of a lack of bony injury. Such pitfalls can be avoided if there is a high index of suspicion in injuries with bruising in the region of the pelvic girdle and the thighs.  Acute Morel-Lavallée lesions tend to be heterogeneous and lobular with irregular margins. Their sonographic appearance becomes more homogeneous and flat or fusiform in shape with a well-defined margin as the lesions age. All Morel-Lavallée lesions were hypoechoic or anechoic, compressible, and located between the deep fat and overlying fascia.⁹ Chronic Morel-Lavallée lesions are treated with open debridement and skin grafting with or without NPWT.¹⁰ This extensive open procedure has a low level of acceptance. Tseng and Tornetta¹¹ recommended using a brush to abrade the lining of the lesion, but the authors felt the brush carries a high risk of infection and skin necrosis. Zhong et al⁶ placed multiple perforated catheters into the cavity, which again carries a high risk of infection. Both studies managed lesions of relatively shorter duration, ranging from 3–17 days. However, the authors needed the minimally invasive method to address 2 aspects: 

1. The removal of the pseudocapsule, performed using the shaver, with minimal disturbance of skin vascularity.  The increased cost of the arthroscopic shaver was much less compared to the increased duration of hospital stay that would be required after open debridment; and
2. The dead space was reduced and maintained by inserting a perforated catheter and connecting it to an intermittent suction device. This allowed the dead space to be eliminated, because the suction catheter ran its entire length and brought together the raw surfaces created by the shaver.  This helped adhesion of the surfaces. 

The authors found a high index of suspicion will lead to early diagnosis in Morel-Lavallée lesion in the absence of underlying fracture. An arthroscopic shaver can facilitate minimally invasive surgery of the chronic lesion by effectively debriding pseudocapsule. Also, intermittent suction will collapse the dead space while still maintaining a closed loop, which is essential to prevent secondary infection. The cosmetic outcome of the procedure has a higher level of patient acceptance and minimal surgical intervention. 

Affiliations: NRI Academy of Medical Sciences, Chinakakani, Guntur, Andhra Pradesh, India

Correspondence: 
Amarnath Surath, MS (Ortho)
Professor, Department of Orthopaedics,
NRI Medical College and General Hospital,
Chinakakani, Guntur, Andhra Pradesh 522503, India
osteosan@yahoo.com 

Disclosure: The authors disclose no financial or other conflicts of interest.