Evaluating the safe application of the Bridging Infix method for anterior pelvic fixation in relation to neighbouring anatomical structures

Abstract

BACKGROUND : Numerous techniques for anterior pelvic fixation exist, however, a novel minimally invasive subcutaneous technique, the Bridging Infix, has been proposed. Although, little is known regarding the risk of injury to anatomical structures in close proximity to the modified implant site. The current study aimed to assess the implant’s proximity to adjacent anatomical structures and palpable bony landmarks to ensure secure and safe fixation. METHODS : An anatomical study was conducted using 50 formalin-fixed cadavers and two fresh-frozen specimens. Dissections were performed to identify and measure the distances between the Bridging Infix implant and critical anatomical structures, including the iliohypogastric nerve, ilioinguinal nerve, superficial epigastric vessels, superficial circumflex iliac vessels, spermatic cord, and the femoral neurovascular bundle. Measurements were also taken between these anatomical structures and relevant bony landmarks. RESULTS : When the Bridging Infix was applied following accepted technical guidelines, no surrounding anatomical structures were compromised. The ilioinguinal and iliohypogastric nerves were shielded by the abdominal muscles and located, on average, 48.96 (SD ± 20.65, range: 10.21–85.26) mm and 31.55 (SD ± 14.45, range:7.42–72.89) mm from the anterior superior iliac spine (ASIS), respectively. The spermatic cord showed no signs of compression by the implant. The superficial epigastric vessels occasionally passed through the medial window field area, while the superficial circumflex iliac vessels were found near the ASIS and lateral window. Nevertheless, vessels can be easily cauterized or ligated when necessary, underscoring the importance of surgeons being familiar with these anatomical relations. In this case, the femoral vessels were positioned deep to the implant, with no gross evidence of direct contact or compression. CONCLUSION : Anatomical structures initially considered to be at risk during the placement of the Bridging Infix were observed to lie at an adequate distance from the fixation point, without macroscopic evidence of implant-related compression. Further studies are required to clinically validate these findings.

HIGHLIGHTS • No anatomical structures were injured during the Bridging Infix proving it is a minimally invasive technique. • Requires surgical expertise, layer-by-layer dissection, full musculature retraction to avoid IHN and IIN injury. • Compression of the spermatic cord and femoral vessels was not observed. • Further quantitative analysis should be conducted to confirm findings and assess potential risks under varying conditions.