Purpose: Although benign, aneurysmal bone cysts (ABCs) are expansile, osteolytic vascular malformations of bone that when located in the spine often cause severe pain and deformity, occasionally presenting with neurologic deficit or cord compression. Although traditionally treated with curettage or en bloc resection, over the last decade, targeted treatment with sclerosing agents has been advocated.
The purpose of our study was to establish the efficacy and safety profile of sodium tetradecyl sulfate foam (Fibrovein 3%) in the percutaneous treatment of aggressive spinal ABCs with pain and/or neurologic compromise.
Methods and Materials: Between July 2015 and January 2020, eight consecutive patients (5 males and 3 females; mean age: 24 years [range: 9–53]) were recruited from a single regional sarcoma unit, following histologic and radiologic confirmation, with unanimous agreement on treatment strategy by the multidisciplinary tumor board. All patients had spinal ABCs, pain, and/or neurologic compromise with imaging and clinical evidence of cord compression in three of the eight patients and neural compression/irritation in four of the eight. All were treated with single or repeated treatment cycles using fluoroscopic or computed tomography (CT)-guided percutaneous intraosseous injection of sodium tetradecyl sulfate foam. The clinical and imaging longitudinal follow-up period was up to 4 years. Procedural data, patient demographics, tumor characteristics, and functional outcomes were recorded.
Results: Technical success was achieved in all cases. Mean procedure length for fluoroscopy was 10 minutes (range: 7–17), compared with 33 minutes (range: 12–54) for CT; one to five treatment cycles (mean: 2.6) were performed using a mean of 2.7 mL (range: 1–6 mL) 3% sodium tetradecyl sulfate foam. Mean dose per procedure was 165 dose length product (DLP) (range: 52–331). Mean spine instability neoplastic score was 10 (range: 7–14). An average follow-up period of 18 months (range: 3–41) was undertaken. In two patients, neurologic compromise persisted after sclerotherapy, due to persistent cord compression requiring emergency en bloc resection and thus was only included in procedural data analysis. All remaining patients demonstrated a significant reduction in pain: presurgical mean of 8.3 (range: 8–9 from a 10-point numerical pain score) to a mean of 3 (range: 2–7) after sclerotherapy (p = 0.04) and a significant percentage reduction in cyst volume (mean: 0.62; range: 0.27–0.91) on serial follow-up magnetic resonance imaging (MRI) (p = 0.009).
Conclusion: Image-guided percutaneous intralesional injection of sodium tetradecyl sulfate foam is a safe, technically feasible, minimally invasive, and effective first-line treatment of primary spinal ABCs causing pain and neurologic compromise. Even if surgery is required, our sclerotherapy technique contributes to reduced intraoperative blood loss. In our experience, early injection, particularly in large lesions with repeated treatment cycles, avoids the requirement for extensive debilitating spinal surgery in pediatric and young adult patients.
Fig. 1 (a) Sacral aneurysmal bone cysts compressing the left S1 nerve in a young male patient. (b) Volumetric magnetic resonance imaging segmentation analysis after initial cycle of sclerotherapy revealed a 30% reduction in cyst volume.
Fig. 2 (a) Axial and (b) sagittal computed tomography (CT). (c, d) Sagittal and axial magnetic resonance imaging (MRI) short tau inversion recovery sequences through a T6 aneurysmal bone cyst that demonstrates progressive consolidation of the lesion, depicted by increased density on CT and low signal on MRI.
Fig. 3 Sequential computed tomography scans performed in an 18-year-old male patient with an aneurysmal bone cyst at L4 (spine instability neoplastic score: 10). After four cycles of sclerotherapy with sodium tetradecyl sulfate foam, there was significant reduction in pain and a 78% reduction in cyst volume with osseous consolidation.
