Simultaneous occurrence of a severe Morel-Lavallée lesion and gluteal muscle necrosis as a sequela of transcatheter angiographic embolization following pelvic fracture: a case report

In the present case, the pathology underlying the severe peripelvic lesion can be explained by considering three entities: the Morel-Lavallée lesions, the gluteal muscle necrosis following TAE, and direct contusion. In particular, the CT image on the seventh day revealed subcutaneous fluid collection and left gluteal muscle damage, indicating both Morel-Lavallée lesions and direct contusion. The intra-operative findings indicated right gluteal muscle necrosis as a sequela of the TAE. To the best of our knowledge, no previous reports have described a case in which these life-threatening conditions were superimposed.

With respect to the present report, only one case of a severe Morel-Lavallée lesion in the pelvis has been reported in the literature [2]. Phillips et al. stated that obesity may increase the risk of developing Morel-Lavallée lesions because it can lead to increased vulnerability of the perforating arteries [2]. In addition, the increased amount of subcutaneous fat may generate a greater shearing force. Because our patient was not obese and did not have any medical history, the seriousness of the lesion was attributed to an extremely high shearing force generated toward both sides of his buttocks. Morel-Lavallée lesions should have been noticed as early as possible, because its early detection and management might have prevented sepsis by controlling the local overgrowth and subsequent dissemination of bacteria. Magnetic resonance imaging (MRI) is considered a reliable modality for describing effusions and determining the lesion type [11]. However, MRI was difficult to perform in our case because of our patient’s state of shock. Ultrasound could be a useful diagnostic tool for detecting the fluid collections and underlying muscle contusion or laceration, as described by some authors, and can be easily performed in patients in shock [12,13]. In light of the present case, an important recognition is that Morel-Lavallée lesions resulting from high-energy injuries can be potentially severe.

Suzuki et al. found that initial traumatic contusion of the gluteal muscles tends to contribute to the development of necrosis [14]. MRI or CT may confirm whether subclinical damage to the gluteal muscles is present. If TAE is needed in a case in which a high risk of necrosis is expected based on CT or MRI, selective TAE should be performed [9].

Both Morel-Lavallée lesions and TAE induce the development of peripelvic soft-tissue ischemia and increase the risk of contamination of any hematoma, with subsequent abscess formation and risk of sepsis [15]. In such severe cases, an open approach and extensive debridement should be performed. However, percutaneous drainage with or without sclerotherapy or vacuum-assisted therapy may be indicated in minor cases [16,17]. In our case, frequent daily debridement with pulsatile irrigation in the intensive care unit was needed after the first surgical debridement and open drainage, in conjunction with the administration of broad-spectrum antibiotics. Thus, the successful healing of severe peripelvic soft-tissue infection requires substantial resources in terms of manpower, material and patience.

The use of free flaps (for example, the rectus abdominis musculocutaneous flap, anterolateral thigh flap and latissimus dorsi muscle) and the free fillet lower leg flap have been reported for the reconstruction of extensive defects after hemipelvectomy or exenteration of a malignancy, with the latter type of flap particularly utilized for hemipelvectomy [18-22]. Butler described the efficiency of the pedicled upper and lower leg in-continuity fillet flap for reconstruction of an extensive hemipelvectomy defect [23]. We used this pedicled fillet flap in the reconstruction for our patient based on the following reasoning: the defect in this case was too extensive to be covered using the above-mentioned free flaps; because his left fractured pelvis was complicated by a deep-bone infection and his left leg was almost completely nonfunctional, hemipelvectomy was unavoidable if our patient was to achieve complete recovery and good ambulatory function; and the defect needed to be covered with a solid flap with sufficient endurance for full weight-bearing if out patient was to wear a prosthesis following the hemipelvectomy. Indeed, no choice other than the chosen procedure (hemipelvectomy and fillet flap from the sacrificed limb) appeared able to resolve the aforementioned problems. A possible explanation for our patient’s left lower limb paresis is ischemia of the sciatic nerve as a sequela of TAE, though direct damage in the initial unstable pelvic fracture might also have contributed to this complication, as described by Suzuki et al. [10].

Our patient described typical phantom limb pain, and rehabilitation was very challenging for him. However, he returned to his previous occupation 24 months after surgery. Some authors have reported that 68% to 72% of patients who undergo surgery for pelvic fracture return to their jobs, with a mean duration of follow-up of 35 to 47 months [24,25]. In the context of these reports, our case achieved quite satisfactory outcomes.