Tear-drop technique in iliac screw placement: a technical analysis

Abstract

Background Instrumentation of the lumbosacral region is one of the more challenging regions due to the complex anatomical structures and biomechanical forces. Screw insertion can be done both navigated and based on X-ray verification. In this study, we demonstrate a fast and reliable open, low exposure X-ray-guided technique of iliac screw placement. Methods Between October 2016 and August 2019, 48 patients underwent sacropelvic fixation in tear-drop technique. Screw insertion was performed in open technique by using an X-ray converter angulated 25-30° in coronal and sagittal view. The anatomical insertion point was the posterior superior iliac spine. Verification of correct screw placement was done by intraoperative 3D scan. Results In total, 95 iliac screws were placed in tear-drop technique with a correct placement in 98.1%. Conclusions The tear-drop technique showed a proper screw position in the intraoperative 3D scan and therefore may be considered an alternative technique to the navigated screw placement.

Surgical Management of Unstable U-Shaped Sacral Fractures and Tile C Pelvic Ring Disruptions: Institutional Experience in Light of a Narrative Literature Review

“…2 ). Nowak et al [ 41 ] in 2021 presented the optimal X-ray placement with 45° axial inclination and 25° sagittal inclination to obtain the teardrop sign in a patient in the prone position.…”

Obturator inlet and iliac oblique technique for safe, convenient, and reliable iliac screw placement

“…The fluoroscopic assisted technique utilizes the teardrop and lateral views to assist with screw placement. In this technique, the starting point, whether the PSIS or S2AI, is determined anatomically or by using the teardrop [11] . In our experience it is incredibly difficult to obtain real-time fluoroscopy on the teardrop view while instrumenting the pelvis since the C-arm is in the way ( Fig.…”

Safe Optimal Tear Drop View for Spinopelvic Fixation Using a Three-Dimensional Reconstruction Model of the Pelvis

“…Although the free-hand technique has been reported to be a safe and effective method for SPF, such as IS or S2AIS insertion, 12 14 21) it was observed that radiological guidance would be required for pathological extremes, such as trauma, tumor, and anatomical variations. 13) The tear drop view, a passage from the PSIS to the AIIS, is used to secure the trajectory for the insertion of the IS or S2AIS. 16) Although the tear drop view is a widely used radiographic view for SPF or acetabular surgery, 20 22) there is a lack of literature documenting a definition of the standard tear drop view and guidelines to obtain this view intuitively.…”

“…Several studies have described SPF techniques, including freehand based on bony landmarks, C-arm fluoroscopy-guided, and navigated or robot-supported techniques. 12 13 14 15 16) The C-arm fluoroscopy-guided technique, generally utilizing the tear drop view, is a reliable and safe method that is essential for patients with anatomical variations, trauma, or tumors. 13) The tear drop view is an overlapped image of the anterior and posterior columns of the pelvis, showing the corridor from the PSIS to the anterior inferior iliac spine (AIIS).…”

“… 12 13 14 15 16) The C-arm fluoroscopy-guided technique, generally utilizing the tear drop view, is a reliable and safe method that is essential for patients with anatomical variations, trauma, or tumors. 13) The tear drop view is an overlapped image of the anterior and posterior columns of the pelvis, showing the corridor from the PSIS to the anterior inferior iliac spine (AIIS). 16) However, to our knowledge, there is a paucity of literature suggesting the optimal tear drop view and definite landmarks in fluoroscopic images to obtain this view.…”