The Anterior Subcutaneous Pelvic Fixator (INFIX) in an Anterior Posterior Compression Type 3 Pelvic Fracture

The purpose of this video is to describe the equipment, anatomy, and surgical technique of anterior subcutaneous pelvic fixation (INFIX) using pedicle screws and a rod in an Anterior Posterior Compression 3 pelvic fracture, as well as how to distract in lateral compression fractures.

The equipment required includes standard spine pedicle screw sets with long screws, 70-110 mm in length, and 7 or 8 mm in diameter. The approach is a mini open and one needs to be familiar with the iliac oblique, obturator outlet, and obturator inlet views. The length of the screw is measured from the sciatic notch to the skin, and they are placed so that the head sits just below the skin. The rod is passed just under the skin along the bikini line and the construct compressed or distracted against a c-clamp while monitored with fluoroscopy. In Orthopaedic Trauma Association C type injuries, we leave c-clamps on the outside the screws to reinforce them or use monoaxial screws. The implants are removed at 3-6 months postop.

The patients tolerate the implants and are able to sit and stand with out difficulty. Complications include lateral femoral cutaneous nerve irritation, heterotopic bone, loss of fixation if the implants are applied incorrectly.

The INFIX procedure for anterior pelvic fixation is based on standard techniques that are familiar to the Orthopaedic Pelvic Surgeon including supraacetabular screws. Rod bending, rod passing, determining the ideal height of the screws, and distraction/compression maneuvers are demonstrated in this video.