Intraoperative Radiographic Detection of Intrapelvic Acetabular Screw Penetration: Lessons Learned From Our Trauma Colleagues

Abstract

Background Intraoperative vascular injury during total hip arthroplasty represents a catastrophic complication. Acetabular screw placement represents one possible mode of injury. The purpose of this study was to evaluate the utility of various fluoroscopic views in the detection of intrapelvic screw penetration. Methods A radiopaque pelvis Sawbones model was instrumented with a hemispherical acetabular component. Four intrapelvic quadrants were defined. Screws were placed, 3 in each quadrant, and imaged sequentially at 3 depths: 0 mm, 5 mm, and 10 mm penetrated. Eight fluoroscopic images were used: anteroposterior, inlet, outlet, iliac oblique, obturator oblique, “down the wing,” obturator outlet, and a “quad” view. Three blinded, independent surgeons evaluated the images for intrapelvic screw penetration. Images were analyzed in isolation and as a “triple-shot series” consisting of the “quad,” obturator outlet, and iliac oblique views. Sensitivity and specificity values were then calculated. Results In isolation, the “quad” view had the highest sensitivity for screw penetration (62%). The triple-shot series was found to be 100% sensitive in all 4 quadrants for detecting 10 mm of screw penetration. The specificity of the series was found to be 100% in all quadrants except for the posterior superior quadrant where it was 67%. Interobserver agreement approached perfection (Kappa ≥0.947) between all surgeons ( P < .001) when using the 3-view series. Conclusions This study is the first to assess the use of fluoroscopy in the detection of intrapelvic penetration of transacetabular screws. We found that a 3-radiograph series provided a sensitive and specific metric for the detection of intrapelvic screw penetration.

Prevention of Pernicious Vascular Event: Acetabular Component Screw Impinging on External Iliac Vessels – A Unique Case Report

“…The “Quad view” described by Wilson et al, projects an image that is parallel to the acetabular quadrilateral plate surface and is very useful for identifying medial wall breaches. The Quad view is nothing but an inlet obturator oblique view of the pelvis [ 9 ]. Diesel et al recommended that every patient undergoing revision hip arthroplasty should ideally undergo a CT Angiography to look for the location of the vessels and their proximity to the prosthetic components if the screw or cement is migrated more than 5 mm beyond the ilioischial line [ 2 ].…”

Incidence of Suboptimal Fluoroscopic Outlet Imaging of the Sacrum and Pelvic Retroversion Necessary for Optimal Views

“…Suboptimal fluoroscopic views of the upper sacral neural foramen can lead to the misinterpretation of the position of instruments and implants relative to osseous and neurovascular structures and subsequently increase the risk of iatrogenic complications. [16][17][18][19][20] The purpose of this investigation was to estimate the prevalence of suboptimal fluoroscopic imaging of sacral outlet views using 5 commercial C-arm models commonly used in pelvis fracture surgery. In addition, we estimate the degree of pelvic retroversion necessary to mitigate this issue using our simple sacral bump technique to reliably obtain optimal outlet imaging for percutaneous posterior pelvic fixation.…”

“…Suboptimal fluoroscopic views of the upper sacral neural foramen can lead to the misinterpretation of the position of instruments and implants relative to osseous and neurovascular structures and subsequently increase the risk of iatrogenic complications. 16–20…”