The "Eiffel Tower" technique: novel long-axis sacroplasty under electromagnetic navigation assistance; feasibility and descriptive study.

ABSTRACT

OBJECTIVES: To describe a novel long-axis multimodal navigation assisted technique - the so-called Eiffel Tower technique - aimed at integrating recent technological improvements for the routine treatment of sacral insufficiency fractures. MATERIALS AND METHODS: The long-axis approach described in the present study aimed at consolidating the sacral bone according to biomechanical considerations. The purpose was (i) to cement vertically the sacral alae all along and within the lateral fracture lines, resembling the pillars of a tower, and (ii) to reinforce cranially with a horizontal S1 landing zone (or dense central bone) resembling the first level of the tower. An electromagnetic navigation system was used in combination with CT and fluoroscopic guidance to overtop extreme angulation challenges. All patients treated between January 2019 and October 2021 in a single tertiary center were retrospectively reviewed. RESULTS: A description of the technique is provided. Twelve female patients (median age 80 years [range 32 to 94]) were treated for sacral insufficiency fractures with the "Eiffel Tower" technique. The median treatment delay was 8 weeks (range 3 to 20) and the initial median pain assessed by the visual analogue scale was 7 (range 6 to 8). Pain was successfully relieved (visual analogue score < 3) for 9 patients (75%) and persisted for 2 patients (17%). One patient was lost during the follow-up. No complication was noted. CONCLUSION: The "Eiffel Tower" multimodal cementoplasty integrates recent technological developments, in particular electromagnetic navigation, with the purpose of reconstructing the biomechanical chain of the sacral bone. KEY POINTS • Sacral insufficiency fractures are common and can be efficiently treated with percutaneous sacroplasty. • The long axis sacroplasty approach can be challenging given both the shape of the sacral bone and the angulation to reach the target lesion. • The "Eiffel Tower" technique is a novel approach using electromagnetic navigation to expand the concept of the long axis route, adding a horizontal S1 landing zone.