ABSTRACT

Vascular reconstruction leads to surgical difficulties such as acute occlusion and critical leg ischemia in childhood rhabdomyosarcoma (RMS) pressuring on the limb’s vascular structures. Finally, amputation is inevitable. Also, use of prostheses to repair bone defects in these cases results in long-term failure or complications such as infection. To avoid a catastrophic problem such as amputation, a vessel-sparing approach and biological bone reconstruction may be a solution in these cases. Here, we present a case of total surgical tumor excision that keeps the native vascular and biologic bone reconstruction in a RMS case involving the left thigh in a two-year-old toddler.

Introduction

Rhabdomyosarcoma (RMS), a soft tissue sarcoma, is very common in children and accounts for approximately 10% to 15% of solid malignant tumors^(1-3). The RMS is heterogeneous and has a rapid, invasive, and infiltrative growth pattern⁽⁴⁾. The outcome depends on primary involvement site, tumor size, histological structure, and the patient’s age⁽⁵⁾. The limbs are invaded in 20% of the cases⁽⁶⁾. The cure chance of RMS increases with a multidisciplinary treatment approach that includes chemotherapy, radiotherapy, and wide excision surgery^{(2, 7)}. Today, limb salvage surgery is applied as standard treatment with the development of surgical techniques, imaging methods, and the presence of vascular grafts^(8,9). Autologous grafts are preferred in these cases compared to prosthetic grafts due to their superior patency^(8,10,11). However, the choice of vascular grafts in children is difficult due to the size limitations of autologous grafts, unusable small-diameter prosthetic grafts, and insufficient surgical experience. The difficulty is increased in toddlers, and limb salvage with vascular repair may be impossible⁽¹²⁾.

Although synthetic bone grafts used to repair the extremity defect provide recovery in the short-term, they are not preferred due to infection and durability problems in the long-term. Biological reconstruction grafts obtained by processing tumor-containing bone tissues with liquid nitrogen may be a more natural and permanent solution^(13,14).

A vascular-sparing surgical approach and the biologic bone autograft technique in childhood RMS will save the limb from amputation because of these difficulties.

Here, we present a case of total surgical tumor excision that keeps the native vascular and biologic bone reconstruction in the RMS case involving the left thigh in a two-year-old toddler.

Case Report

A two-year-old girl was admitted with a huge left thigh mass adjacent to the femoral bone’s medial side. The patient had pain in her left thigh with stiffness and swelling for about five months. The patient did not have a family history of malignant disease or recent trauma. There was a mass of 6 cm x 12 cm in the left thigh on physical examination (Figure 1). No neurologic deficits were detected. On magnetic resonance imaging (MRI), a large mass of 6 cm x 12 cm was detected in the middle of the left thigh, compressing the neurovascular bundle (Figure 2a). The MRI showed that the femoral artery, femoral vein, and femoral nerve were compressed laterally by the tumor (Figure 2b). On positron emission tomographic imaging, the patient had a few small metastatic lesions in her lung. A tissue sample was taken from the patient with a trucut needle biopsy under ultrasound guidance with an anteromedial approach. Histopathological diagnosis was embryonal RMS. The lesion in the femoral bone segment persisted after preoperative chemotherapy.

Surgical Procedure

Two weeks after the diagnosis, the surgical procedure was performed with an anteromedial approach to protect the natural vascular structure and save the limb (Figure 3). Skin and subcutaneous incisions were made from the groin to the distal of the limb in a longitudinal fashion. The neurovascular bundle was exposed without touching the tumor from the lateral of the tumor. The superficial femoral artery and vein and the femoral nerve were exposed and protected by making a gentle dissection. Since the most important factor for successful sarcoma surgery is wide resection, the deep femoral artery was ligated just below the femoral bifurcation and the deep femoral vein at the level of the saphenofemoral junction. Distal pulses were checked, and no ischemia was observed. Both arterial and venous flows were sufficient.

According to the concept of surgical margins, wide resection was made with soft tissue mass and 5-centimeter femoral bone resection (Figure 4). The tumoral mass was stripped from the bone segment, including the periosteum. Aggressive curettage was applied to the intramedullary cavity. Then, the bone segment was frozen with liquid nitrogen for 20 minutes. The bone segment was thawed at room temperature for 20 minutes and in distilled water for 15 minutes. Ultimately, a bone graft was obtained, which provided the best morphological matching from the bone segment. (Figure 5). Subsequently, the bone graft was fixed with a 3.5 mm reconstruction plate (Figure 6). The wound was irrigated and sutured in a standard fashion. The operation was completed successfully.

The patient’s pedal pulses were checked regularly after surgery. The patient was discharged on the seventh postoperative day without any signs of ischemia. The pediatric oncology clinic planned postoperative radiotherapy for lung metastasis and neo-adjuvant chemotherapy. Pathological samples confirmed the diagnosis and showed that all sides of the resected tumor mass were tumor-free.

Results

There was no loss of function in the left lower limb (Figure 7). In the postoperative second month’s control examination, the patient was walking comfortably, and no neurological or orthopedic problems were detected. The patient continued the chemotherapy program.

Currently, the patient has had her five-month follow-up. The patient had no limb length discrepancy at her last follow-up. There was no problem with her bone growth and limb circulation. Finally, no tumor recurrence was detected in the left lower limb of the patient during the five-month follow-up.

Discussion

Soft tissue sarcomas such as RMS is a rare condition in children⁽⁸⁾. Limb loss may occur because of vascular involvement by the tumor⁽¹⁵⁾. Vascular reconstructive surgery may be required in such cases⁽²⁾. However, in infants and toddlers, reconstruction is difficult due to small diameter vein grafts, or prosthetic grafts, which trend to thrombosis⁽¹²⁾. Vascular reconstruction surgery may be necessary to avoid catastrophic consequences such as amputation due to distal limb ischemia⁽¹⁵⁾. However, in toddlers, arteries or veins are of relatively small diameter⁽¹²⁾. Therefore, the vascular reconstruction procedure is often complicated due to small-sized native grafts or small diameter prosthetic grafts. Sometimes, amputation is mandatory because artificial grafts applied to small vessels are thrombosed⁽¹²⁾.

Furthermore, the neurovascular bundle is under pressure if the tumor invades the package^(3,16). There are various intervention scenarios to preserve the affected limb⁽¹⁶⁾. Although otherwise claimed⁽¹²⁾, most surgeons cannot dare to ligate the main arteries in the toddlers in tumor operations with a high risk of amputation by trusting on collateral circulation. There are insufficient diameter and length of native grafts, such as a great saphenous vein in toddlers⁽¹²⁾, and a high risk of thrombosis of prosthetic grafts complicates the surgical intervention to recover the affected limb^(2,8,16). There are two options back to recover the tumor invaded by the tumor; amputation or vessel-sparing surgery. Vessel-sparing surgery is possible only with an experienced surgical team and a rigorous tissue resection, and the results are excellent^{(1,4,6-9,15,16)}. Today, limb salvage surgery is now accepted as a standard treatment method in limb sarcomas^(8,9), and the number of surviving limbs is higher than the number of amputations^(1,7). This treatment model change was made possible by advancing surgical techniques, introducing new imaging methods, and developing vascular grafts⁽¹³⁾.

Our team was ready before the operation for possible vascular reconstruction scenarios. In case of failure to protect the vascular structures, our first alternative was to create a new graft by opening the great saphenous vein of the patient with a diameter of 1.7 mm linearly and wrapping it around a Hegar dilator. In case this was not possible, we had planned to use a biological vein graft. Our worst scenario was transfemoral amputation.

Another goal of the treatment should also be to restore bone defects that preserve the affected limb’s length and function. Arthroplasty is one of the choices, especially in adult patients. However, biological reconstruction is important, especially in children. We used the biological reconstruction technique “frozen autograft treated with liquid nitrogen” for this toddler^(13,14).

Liquid nitrogen-inactivated autologous bone graft is a safe method for primary malignant extremity tumors. This method has a low complication rate and high bone healing rate, and also offers a satisfactory limb function⁽¹⁷⁾.

In our case, the patient’s age, clinical and radiographic findings have encouraged us to prefer a limb-sparing surgical technique that preserves native neurovascular bundle and bone structure. Our approach in toddlers with malignant limb soft tissue tumors adjacent to vascular structures can be applied successfully and it can prevent amputation. We believe that the vessel-sparing surgery can be the first choice for standard surgical technique in toddlers in terms of better cosmesis, low morbidity, and loss of function in huge sarcomas threatening the limb.