This video demonstrates a modified open lumbopelvic fixation technique designed to minimize invasiveness while maintaining effective stabilization of the lumbosacral junction when open surgery is unavoidable, such as in cases requiring direct sacral access for trauma, tumors, or other pathologies. The procedure is illustrated through the case of a 56-year-old female patient with metastatic breast carcinoma involving the sacrum, complicated by nerve compression and urinary retention. The surgical approach involves a linear midline incision, meticulous subfascial dissection to preserve the Longissimus thoracis and Iliocostalis lumborum muscles, and a subcutaneous supra-fascial approach for iliac screw placement guided by intraoperative CT navigation. A U-shaped cross-link is incorporated to ensure final construct stability. In this case, the patient underwent successful lumbopelvic fixation with nerve root decompression and partial tumor resection. Postoperatively, no new neurological deficits were observed, and sphincter function progressively improved. The technique minimized soft tissue disruption, blood loss, and potential complications typically associated with more extensive dissection. Six-month follow-up CT scans confirmed the stability of the fixation construct and the residual lesion. As of March 2026, more than 18 months following the June 2024 surgery, the patient demonstrates stable clinical and radiological disease control. This video highlights how the subcutaneous supra-fascial approach for iliac screw placement, combined with muscle preservation and a U-shaped cross-link, offers a less invasive alternative when open lumbopelvic fixation is required, potentially reducing soft tissue trauma, complications, and facilitating faster recovery, particularly in patients with sacral metastases requiring nerve decompression and tumor resection.