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. 2022 Apr;12(2_suppl):45S-52S.
doi: 10.1177/21925682211036664.

Challenges and Complications in Freehand S2-Alar-Iliac Spinopelvic Fixation and the Potential for Robotics to Enhance Patient Safety

Ayush Arora  1 , Sigurd Berven  1
Affiliations

Challenges and Complications in Freehand S2-Alar-Iliac Spinopelvic Fixation and the Potential for Robotics to Enhance Patient Safety

Ayush Arora et al. Global Spine J. 2022 Apr.

Abstract

Study design: Narrative Summary Review for Navigation & Robotics Focus Issue.

Objective: To discuss the challenges and complications of S2-Alar-Iliac (S2AI) spinopelvic fixation using freehand techniques, and to introduce the utility of navigation & robotics to enhance patient safety.

Methods: This study involved search of literature using the PubMed database, including retrospective clinical studies, anatomic reports, and surgical reports. The intention was to find literature that discussed complications regarding screw malfunction from manual S2AI placement, anatomical complexity of the sacroiliac joint, and outcomes of S2AI procedures conducted with robotic guidance systems.

Results: The sacroiliac joint presents numerous complexities that can lead to challenges in free-hand placement of the S2-alar-iliac screw. Anatomic considerations of the S2AI screw involve close proximity to vital neurovascular structures, including: superior gluteal vessels, external iliac vessels, pudendal vessels, superior gluteal nerves, sciatic nerve, sympathetic chain ganglia, and pudendal nerves. The complications associated with manual S2AI screw installation include screw misplacement, breach of cortical bone, and injury to neurovascular structures. Robotic techniques for establishing S2AI screws involve greater accuracy of screw placement and reduced complications.

Conclusions: Accurate placement of S2AI screws is compromised by variation in pelvic anatomy and by a pathway that traverses dense cortical bone of the sacroiliac joint. Accurate placement of S2AI screws is important for patient safety regarding neurovascular structures, and for effective, stable fixation across the SI joint. Robotic navigation of S2AI fixation offers significant utility in improving the accuracy of screw placement and patient safety.

Keywords: iliac; patient safety; pelvic; robotic assisted surgery; sacroiliac joint; sacrum; screw.

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Conflict of interest statement

Declaration of Conflicting Interests: The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Figures

Figure 1.
Figure 1.
Posterior spinal arthrodesis supplemented with pelvic fixation involving iliac and S2-alar-iliac screws.
Figure 2.
Figure 2.
Posterior view of osseous landmarks. Note that blue dashed lined is path for the S2AI screw. Image courtesy of complete anatomy.
Figure 3.
Figure 3.
Anterior view of vascular structures. The red box indicates vessels that lie in anterior pelvis within proximity to the S2AI screw, within the sciatic notch. Moreover, the S2AI screw terminates at the AIIS, indicated by the arrow. Note that blue dashed lined is path for the S2AI screw. Image courtesy of complete anatomy.
Figure 4.
Figure 4.
Posterior view of vascular structures. The red box indicates vessels that lie inferior to the starting point of the S2AI screw, within the sciatic notch. Note that blue dashed lined is path for the S2AI screw. Image courtesy of complete anatomy.
Figure 5.
Figure 5.
At-risk neural structures that lie anterior to the S2AI screw. Note that blue dashed lined is path for S2AI screw. Image courtesy of complete anatomy.
Figure 6.
Figure 6.
At-risk neural structures that lie inferior & posterior-superior to the S2AI screw. Note that blue dashed lined is path for S2AI screw. Image courtesy of complete anatomy.
See this image and copyright information in PMC

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