Relações vasculares dos ramos ileopúbicos e sua implicação clínica na fixação retrógrada percutânea

Abstract

Background Pelvic ring fractures, though relatively rare, are a significant concern in orthopedic trauma, particularly as they frequently involve the iliopubic (IP) rami. These structures are crucial for pelvic stability and locomotion. Injuries to the IP rami can lead to functional impairment and prolonged recovery. Traditional open reduction and internal fixation (ORIF) is widely used but presents challenges such as invasiveness, surgical duration, and postoperative complications. Consequently, percutaneous retrograde fixation has emerged as a less invasive alternative. However, a precise understanding of the anatomical and radiological parameters governing screw placement is essential to minimize complications and optimize outcomes. Questions/Purposes This study aims to (1) describe the morphology and anatomical variations of the IP rami, (2) define a potential safety corridor for percutaneous screw fixation, (3) analyze the relationship between the IP rami and major neurovascular structures, and (4) discuss our findings by comparing with previous reports in different populations to identify anatomic differences, patterns, and surgical important relations. Patients/Methods A retrospective cross-sectional analysis was conducted on 29 patients (25 on the left and 23 on the right totalizing 48 IP rami), using high-resolution computed tomography (CT) scans, being only possible to compare the left and right values in 19 cases, having not found significant differences between the left and right sides in any variable. Morphometric parameters were recorded, including rami shape, diameters, and their relationship with neurovascular structures. Patients were 18 years or older, of Caucasian descent, with adequate CT imaging. Cases with severe fractures, metabolic bone disorders, or tumors were excluded. Statistical analysis assessed variations based on sex, laterality, and fracture status. The reliability of measurements was ensured through intraclass correlation coefficients (ICC), and comparative analyses were conducted using nonparametric tests. Results (1) The most common rami shapes were triangular and trapezoidal, with circular and quadrangular shapes occurring less frequently. (2) The median narrowest diameter is significantly larger in males (8.67 mm) than in females (6.83 mm) (p=0.011) on the left side, which influences screw selection. (3) The obturator neurovascular bundle is located at a median distance of 3 mm from the IP rami on both the left (p=0.976) and right sides (p=0.146), highlighting the risk of neurovascular injury during fixation. The external iliac vein (EIV) is positioned approximately 5 mm from the rami, while the external iliac artery (EIA) is located at a median distance of 11 mm. Significant sex-based differences in the proximity of the external iliac vein to the IP rami on the left side were observed (p=0.032). Conclusion Our findings highlight the importance of preoperative planning and real-time imaging to minimize neurovascular injury risks. The proximity of the obturator neurovascular bundle and external iliac vessels to the IP rami necessitates precision in percutaneous fixation techniques. The EIV, lying closer to the rami at approximately 5 mm, presents a higher risk of iatrogenic injury than the EIA, which is positioned at 11 mm. Given anatomical variations, tailored screw selection is essential, with 6.5 mm screws generally safer for males and 4.5 mm for females. Female patients may have a higher risk of vascular injury due to their narrower IP rami and closer external iliac vessels positioning. Future research should focus on larger sample sizes and advanced imaging techniques to refine neurovascular safety corridors and improve surgical safety. Level of Evidence: Level IV.