Patient-specific 3D reconstruction models for sacral tumor resection: illustrative cases

Abstract

Background: The surgical methods used to resect sacral tumors are extensive and require maneuvering through complex anatomical systems such as the pelvic organs and sacral nerve roots. These procedures may result in complications and adverse patient outcomes. The technology integrating 3D reconstruction models in the field of spine surgery is rapidly evolving, and these challenging cases present a unique opportunity to leverage this technology's capability for enhanced patient outcomes.

Observations: The authors present two sacral tumor cases diagnosed with synovial cell sarcoma and giant cell osteosarcoma, respectively. Both patients underwent a three-staged en bloc tumor resection assisted by 3D reconstruction models. Postoperative imaging showed a complete tumor resection, and the patients symptomatically improved, with no signs of recurrence on follow-up.

Lessons: Surgical planning and execution have clearly advanced significantly with the introduction of 3D modeling into spine surgery. Based on the authors' experience, this technology can be used to improve outcomes for complicated spinal tumors with successful results. Although these results are encouraging, extensive studies with larger patient cohorts must be carried out to fully appreciate the technology's advantages across a range of patient demographics and tumor types. https://thejns.org/doi/10.3171/CASE2522.

Keywords: 3D reconstruction; sacral tumor; sacrectomy; sarcoma.

FIG. 1.

A: Coronal CT scan depicting the lesion arising at the level of S2–3 extending inferolaterally. B: Enlarged axial CT scan of the lesion showing the right S2 foramen. C and D: Axial T1-weighted with contrast out-of-phase MR image (C) and axial T1-weighted MR image (D) showing an enhancing mass extending anteriorly in the presacral space.

FIG. 2.

A: A 3D reconstruction model of the tumor utilizing preoperative thin-slice CT and MRI, showing spinal anatomy, in particular, extension and segmentation of the sarcoma (green) and nerve roots (purple). B:The SyncAR Spine screen on an operating room monitor positioned bedside, facing both the primary and assisting surgeons, which displayed the navigated 3D model, helping significantly during the four osteotomy cuts. C: The 3D model as observed by the surgeon from the SyncAR Spine monitor cart in the operating room, which the surgeon can review prior to the case.

FIG. 3.

A:Postoperative coronal CT scan showing L4 to pelvis fusion. B: Postoperative axial CT scan showing pelvic instrumentation. C and D: Postoperative coronal (C) and sagittal (D) radiographs showing intact L4 to pelvic construction at the 3-year follow-up.

FIG. 4.

A: CT scan (slice thickness 1.25 mm) depicting a left lytic lesion. B and D: Axial (B) and coronal (D) STIR MR images showing the presence of an enhancing lesion extending into the left sacral ala. C:Three-dimensional reconstruction models of the tumor utilizing preoperative thin-slice CT and MR images, showing spinal anatomy, in particular, segmentation of the osteosarcoma (green), dural sac (blue), and L5–S3 nerve roots (purple).

FIG. 5.

A: Axial postoperative CT scan depicting resected sacral bone and pelvic instrumentation. B: Coronal postoperative CT scan depicting L3 to pelvis fusion. C: Sagittal postoperative radiograph showing L3 to pelvis screws. D:Coronal postoperative radiograph showing L3 to pelvis screws.