Neuronavigated placement of iliosacral screws in sacral fractures: an additional tool in the spine surgeon’s arsenal

Introduction

Sacral fractures have the specificity of involving both the caudal part of the spine and the posterior part of the pelvic ring, thus requiring both spinal and orthopedic surgical expertise. Occurring in approximately 60% of pelvic ring fractures (1), they usually follow high-energy trauma in young patients and low-energy trauma in elderly subjects (2,3). The classification of such traumatic injuries is complex, and depends on the presence of fractures of the anterior part of the pelvic ring, such as involvement of the pubic rami or disjunction of the pubic symphysis (4). While minimally displaced pelvic fractures can be treated conservatively, surgical fixation or even decompression is justified for unstable fractures or those that threaten neurological elements, or more simply to avoid prolonged bed rest (5-7). The decision must then be multidisciplinary, taking into account both pelvic and spinal anatomical considerations (8). In this context, vertical sacral fractures described according to Denis’s anatomical zones (9) and iliosacral disjunctions are most often eligible for percutaneous iliosacral screw fixation, which effectively reduces and mechanically stabilizes this type of injury, and whose minimally invasive nature reduces blood loss and decreases the infection rate (10). Initially described with the use of fluoroscopy (11), the traditional technique nevertheless exposes a significant risk of iatrogenic lesions of the nerve structures, and in particular of the L5, S1 and S2 roots (12,13). Indeed, their oblique trajectory through their respective foramen makes their deductive positioning difficult in conventional two-dimensional (2D) X-rays, especially in traumatic conditions where the pelvic morphology is often significantly modified. Furthermore, the advent the routine use of intraoperative three-dimensional (3D) imaging systems in spinal surgery has made it possible to improve the precision of pedicle screw placement, while reducing radiation exposure to staff members (14). Thus, it is quite logical that its application to iliosacral screw fixation offers the same safety advantages, including greatly increased precision, making its use almost obligatory for this condition (15-17). In this article, we propose to describe simply the surgical technique for the percutaneous placement of iliosacral screws in cases of vertical fractures of the sacrum or iliosacral disjunction, with the common aim of both providing suitable educational support, and democratizing this strategy among spine surgeons, and especially neurosurgeons. We present this article in accordance with the SUPER reporting checklist (available at https://jss.amegroups.com/article/view/10.21037/jss-25-144/rc).

Preoperative preparations and requirements

Anatomy

Pelvic ring

The pelvic ring is a complex anatomical structure composed of the hip bones, sacrum, and coccyx, forming a complete bony ring (Figure 1). It plays a crucial role in human stability and mobility, transmitting weight from the upper body to the lower limbs and providing protection to the pelvic viscera, vessels, and nerves. The hip bones form the anterolateral parts of the pelvic ring, united anteriorly at the pubic symphysis, while the sacrum and coccyx form its posterior part, connecting to the lumbar spine. The pelvic ring’s stability is supported by ligaments such as the sacroiliac, iliolumbar, sacrospinous, and sacrotuberous ligaments, which are crucial for maintaining the integrity of the pelvic structure (4).

Figure 1 Anterior (left) and posterior (right) views of the pelvic ring. Vertical sacral fractures are commonly classified using the Denis zones (orange parts from 1 to 3), based on anatomical location and relationship to neural structures: zone 1 (transalar), zone 2 (transforaminal) and zone 3 (central) (9). The red lines demonstrate disjunctions of the right sacroiliac joint and pubic symphysis, while the dotted lines show a zone 2 sacral fracture.

Hip bone

The hip bone is a complex structure formed by the fusion of three bones: the ilium, ischium, and pubis (18). These bones converge at the acetabulum, that articulates with the femoral head to form the hip joint. The ilium connect to the sacrum by the C-shaped sacroiliac joints. The left and right hip bones connect to each other medially and anteriorly to form the pubic symphysis.

Sacrum

The sacrum is formed by the fusion of five sacral vertebrae in kyphosis, the first one (S1) being the largest and allowing strong screw placement (19). Laterally, the sacral wings extend and articulate with the ilium to form the sacroiliac joints. The upper part of the sacrum (S1) connects with the last lumbar vertebra (L5), and its lower part with the coccyx. The sacrum contains posteriorly the distal part of the spinal canal, communicating to the pelvic space anteriorly via the 4 sacral foramina through which the sacral roots from S1 to S4 exit.

Ligaments

The pelvic ring is stabilized by a complex network of ligaments, including the anterior and posterior sacroiliac ligaments, iliolumbar, sacrospinous, sacrotuberous, and pubic symphyseal ligaments (20).

Indications, limitations

Iliosacral screw fixation is indicated in trauma cases of vertical fracture of the sacrum or iliosacral disjunction (Figure 1) (6,16). It is essential before performing such a surgical procedure to consult collegially with the orthopedic team, in order to consider the bony pelvis in its entirety, and not only in its posterior part. Indeed, it is rare that a posterior pelvic traumatic lesion is isolated and that the ischiums, associated branches and pubic symphysis are spared.

Preoperative assessment

In cases of high-energy trauma, where multiple injuries are suspected, a full-body computed tomography (CT) scan is performed, allowing for a detailed analysis of traumatic injuries, particularly in the spine and pelvis, enabling analysis of fracture lines, joint dislocations, displacement of fragments, and the overall morphology of the pelvis. In cases of low-energy trauma, a CT scan of the pelvis and lumbar spine is sufficient.

Specific information for the patient

The surgeon must provide the patient with comprehensive information about the procedure to ensure informed consent. The patient should be made aware of potential risks such as infection, hematoma, pseudarthrosis, and the possibility of long-term pelvic pain following the procedure. Additionally, the surgeon must discuss the expected rehabilitation process, noting that the timing for standing will be determined in consultation with the orthopedic team, largely depending on the status of the anterior pelvic ring, which influences overall pelvic stability. The study was conducted in accordance with the Declaration of Helsinki and its subsequent amendments. The study was approved by the local ethics board of Assistance Publique-Hôpitaux de Marseille (No. CSE26-3). Written informed consent was obtained from the patient for the publication of this article, accompanying images and video. A copy of the written consent is available for review by the editorial office of this journal.

Step-by-step description

Positioning and set-up

The patient is placed in a prone position under general anesthesia (Figure 2, Video 1). The neuronavigation system is installed using 2D mode, ensuring that the posterior portion of the pelvis, including the sacrum, sacroiliac joints, and iliac wings, is within the acquisition field. The bone-gripping referencing frame is positioned on the posterior superior iliac spine, on the non-fractured side in case of unilateral procedure. In cases of bilateral damage, it should be placed on the side that is least displaced or unstable.

Figure 2 Positioning (A) and surgical draping of the patient (B). The reference frame is positioned on the posterior superior iliac spine, on the non-pathological side for unilateral damage (green star) or the one appearing most stable for bilateral damage. The vertical skin incision (orange line) is performed at the posterior and superior part of the gluteal region.

Screw placement

As with any surgical procedure involving puncture, drainage, or screw placement, three parameters must be established: an entry point, a trajectory, and a length. Typically, two screws are necessary and sufficient, either both placed in S1 or one in S1 and the other in S2, depending on the patient’s anatomy (possibility of dysmorphic sacrum). It is generally easier to place both screws in S1 due to the smaller size of S2. The upper screw, usually the longest, is placed first, ensuring that it spares the sacral foramina, particularly those containing the S1 roots. A single straight vertical 2 cm skin and fascial incision is made in the upper part of the gluteal region, using neuronavigation projection (Figure 2). The gluteal muscles are then bluntly dissected using the finger until reaching the ilium. The neuronavigated drill guide (or navigated Jamshidi needle) is impacted on the first entry point located on the lateral side of the ilium. The planned trajectory should cross the ilium, the sacroiliac joint, and the sacral wing to reach the upper part of the body of S1, sparing the sacral canal foramina. The length is calculated to significantly outreach the disjunction or fracture, in order to achieve optimal stability. In unilateral procedures, the screw may cross the midline. It is crucial to record the position of the first screw on the neuronavigation system at this early step, to avoid trajectory conflicts with the second one. Once the optimal trajectory is chosen, an orthopedic drill machine is used, taking care to first adjust the appropriate length of the neuronavigated guide. A K-wire is then inserted, prior to placing the definitive screw. A 7.3 mm diameter and partially or fully threaded cannulated self-drill screw is employed for joint compression or fracture reduction. A washer is necessary to maximize purchase on the ilium without burying the screw head in the bone (Figure 3). It is advisable not to reduce the fracture or disjunction to the maximum with the first screw before achieving the trajectory of the second, to avoid altering the anatomical conformation displayed on the neuronavigation. The second screw is then placed according to the same technique. The two K-wires remain in place until a second 3D acquisition is performed to verify the screws positioning, in case it becomes necessary to remove one and reposition it. Once satisfactory screw placing is confirmed, optimal reduction of the sacral wing fracture or sacroiliac dislocation can be achieved after removing the K-wires. The skin is then closed using standard techniques.

Figure 3 Materials needed for placement of iliosacral screws: a bone gripping reference frame, a neuronavigated drill guide (navigated Jamshidi needle), a drill machine, a K-wire and a screwdriver. Two 7.5 mm diameter and partially threaded screws with washer are selected according to the desired length, and then placed to achieve joint compression or fracture reduction, and bone stability.

Postoperative considerations and tasks

Patient mobilization and weight-bearing protocols are determined through close collaboration with the orthopedic team, taking into account the stability of both anterior and posterior elements of the pelvic ring. In the case of preserved or surgically restored anterior pelvic integrity, early mobilization in sitting and standing positions can be considered, to be modulated according to other traumatic lesions and the patient’s pain. Postoperative CT-scan or X-rays are routinely performed to confirm screws’ position and monitor for complications and follow-up (Figure 4).

Figure 4 Illustrative case of a 54-year-old patient who was the victim of a road traffic accident and was surgically treated with right iliosacral screw fixation under neuronavigation. Preoperative pelvic X-ray and CT scan (A) demonstrate a right iliosacral disjunction and a fracture of each iliopubic branch. Postoperative follow-up examinations (B) demonstrate the correct positioning of the two iliosacral screws at S1 and S2, with a slightly ascending trajectory and sparing the sacral foramen. The anterior pelvic arch fractures were treated conservatively. CT, computed tomography.

Tips and pearls

Collaboration through collegial discussions with the orthopedic team is essential for optimal decision-making, particularly concerning anterior pelvic stability which is usually addressed first. The use of intraoperative 3D navigation is critical, as it provides real-time anatomical guidance and anatomical precision. The referencing frame is positioned on the posterior superior iliac spine, on the non-fractured side or the most stable side in case of bilateral damage. After positioning the screws, it is advised to leave K-wires in place until the control 3D scan confirms correct screw location, facilitating removing of the screws if necessary. For sacral fractures, fully threaded screws are preferred to avoid excessive compression. For iliosacral disjunction, the screws should be partially threaded and be placed perpendicular to the joint to achieve reduction. This technique allows reduction in the axial plane but not in the vertical one.

Discussion

Patient selection and contraindications,

Neuronavigated iliosacral fixation is indicated in cases of vertical sacral fractures and sacroiliac joint disruptions (21). Iliosacral screw, especially in the S2 segment, should be used with caution in patients with suspected pelvic or sacral osteopenia or osteoporosis due to increased risk of fixation failure and loss of reduction (22). Other contraindications include active infection, significant dysmorphism without a safe screw corridor and neurological impairment requiring decompression (10).

Comparative outcomes

The evolution from conventional fluoroscopy to intraoperative 3D neuronavigation has significantly improved the safety and accuracy of iliosacral screw fixation. Comparative studies demonstrate that navigation-assisted techniques yield higher screw placement accuracy, lower malposition and reoperation rates, shorter operative time, and substantially reduced radiation exposure for both patients and surgical teams compared to fluoroscopic guidance (23,24). For illustrative purpose, Prost et al. found a malposition rate of 0% and a revision rate of 0% in navigation-guided cases, compared with 10.9% and 7.3%, respectively, in the fluoroscopy group. Operative time with navigation averaged 39±20 vs. 60±33 minutes for fluoroscopy. Patient radiation dose was also significantly lower in the navigation group (mean 1.5–2.5 mSv) compared to fluoroscopy (4.0–8.5 mSv). Importantly, navigation also protects the surgical team by allowing them to exit the room during 3D image acquisition, reducing team exposure to <0.1 mSv per case (23-25). Additionally, navigation allows immediate intraoperative correction of malpositioned screws, potentially obviating the need for postoperative CT scanning. Intraoperative and postoperative complication rates seem similar between neuronavigated and conventional techniques. In a large retrospective study, Zwingmann et al. demonstrated that intraoperative complications occurred in 8.8% of navigated cases vs. 5.9% of conventional cases (P=0.42), and postoperative complications in 26.3% vs. 29.3% (P=0.65) (26). Other comparable studies confirm no significant difference in overall complication rates (27,28).

Practical ranges

Despite the lack of data regarding the cost-effectiveness of neuronavigated placement of iliosacral screws and the initial financial investment and maintenance costs of spinal neuronavigation systems, larger studies addressing this issue more comprehensively by including all neuronavigated procedures allow us to conclude that this expense is justified and economically offset if the flow of treated patients is high (29). Workflow is impacted by an additional 10–30 minutes for setup, however, this time is offset by a shorter operating time of approximately 39 minutes for the neuronavigated technique vs. 60 minutes on average for fluoroscopy (23). The learning phase can be estimated at 5–10 cases, reflecting the simplification of the procedure compared to the conventional method using fluoroscopy, which is significantly more technically demanding and therefore takes longer to master (30).

Weight-bearing protocols

Weight-bearing protocols depend on the stability and management of the anterior pelvic ring. If the anterior ring is intact or has been surgically stabilized, early mobilization and weight-bearing as tolerated can be initiated. Conversely, if the anterior ring is unstable and untreated, patients should remain non-weight-bearing or have only touch-down weight-bearing for 4–6 weeks, with wheelchairs used in cases of bilateral instability. Alternative fixation such as lumbopelvic constructs allows immediate full weight-bearing (31).

Sacral dysmorphism

Sacral dysmorphism is characterized by deviations from the typical sacral anatomy, most notably in the upper sacral segment. Key features include a narrow and angled osseous corridor, acute alar slope, mammillary bodies, residual disc between S1 and S2, non-circular or misshapen sacral foramina, tongue-in-groove sacroiliac joint surface, and the upper sacrum not being recessed in the pelvis (32,33). These features can be identified on CT scans or specific pelvic radiographic views and present significant challenges for iliosacral screw fixation. By significantly enhancing the identification of safe bony corridors, neuronavigation therefore reduce the risk of screw malposition and neurovascular complications compared to conventional fluoroscopy (27,34). Sacral dysmorphism often results in narrower and more oblique S1 corridors, sometimes precluding safe screw placement. Preoperative 3D CT analysis and virtual planning are essential for visualizing optimal screw trajectories and assessing corridor eligibility (35,36). In many dysmorphic cases, the S2 segment provides a larger and safer alternative for screw fixation (37,38).

Future perspectives

The Ramadanov-Zabler Safe Zone is a promising novel CT-based computational method, designed to enhance the safety and precision of iliosacral screw placement (39). By mapping regions of higher bone density in the sacrum, this approach identifies optimal intraosseous pathways for screw insertion, aiming to minimize neurovascular injury and cortical breaches. The safe zone is established through detailed 3D CT segmentation and 2D projection, highlighting high-density bone regions for screw trajectory planning, and can be integrated into neuronavigation systems, allowing intraoperative alignment with the pre-defined safe zone for real-time guidance. While early results are encouraging, further clinical validation is required before widespread adoption.

Conclusions

The use of 3D neuronavigation for iliosacral screw fixation represents a major advancement in the management of posterior pelvic ring injuries. This technique enhances surgical precision, reduces the risk of iatrogenic nerve injury, and minimizes radiation exposure for both patients and practitioners. By fostering close collaboration between neurosurgeons and orthopedic surgeons, this multidisciplinary approach ensures comprehensive care of complex pelvic trauma. The standardized and simplified workflow described here democratizes access to advanced fixation strategies, making them feasible for a broader range of spine surgeons. As evidence continues to support its clinical benefits, 3D neuronavigation is poised to become the gold standard in iliosacral screw fixation, ultimately improving outcomes and safety for patients with pelvic ring injuries.

Acknowledgments

None.

Footnote

Reporting Checklist: The authors have completed the SUPER reporting checklist. Available at https://jss.amegroups.com/article/view/10.21037/jss-25-144/rc

Peer Review File: Available at https://jss.amegroups.com/article/view/10.21037/jss-25-144/prf

Funding: None.

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://jss.amegroups.com/article/view/10.21037/jss-25-144/coif). The authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. The study was conducted in accordance with the Declaration of Helsinki and its subsequent amendments. The study was approved by the local ethics board of Assistance Publique-Hôpitaux de Marseille (No. CSE26-3). Written informed consent was obtained from the patient for the publication of this article, accompanying images and video. A copy of the written consent is available for review by the editorial office of this journal.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

References

1. Beckmann N, Cai C. CT characteristics of traumatic sacral fractures in association with pelvic ring injuries: correlation using the Young-Burgess classification system. Emerg Radiol 2017;24:255-62. [Crossref] [PubMed]
2. Gutierrez-Gomez S, Wahl L, Blecher R, et al. Sacral fractures: An updated and comprehensive review. Injury 2021;52:366-75. [Crossref] [PubMed]
3. Yildiz U, Kandziora F. Sacral Fractures. In: Meyer B, Rauschmann M, editors. Spine Surgery. Cham: Springer International Publishing; 2019:299-308.
4. Pascal-Moussellard H, Hirsch C, Bonaccorsi R. Osteosynthesis in sacral fracture and lumbosacral dislocation. Orthop Traumatol Surg Res 2016;102:S45-57. [Crossref] [PubMed]
5. Wafa MA, Fahmy FM, Mahmoud Mohamed Metawea HMM. Sacral Fractures Treatment: Systematic Review and Meta-Analysis. QJM: An International Journal of Medicine. 2024;117:hcae070.391.
6. Hak DJ, Baran S, Stahel P. Sacral fractures: current strategies in diagnosis and management. Orthopedics 2009;32: [Crossref] [PubMed]
7. Aprato A, Branca Vergano L, Casiraghi A, et al. Consensus for management of sacral fractures: from the diagnosis to the treatment, with a focus on the role of decompression in sacral fractures. J Orthop Traumatol 2023;24:46. [Crossref] [PubMed]
8. Santolini E, Kanakaris NK, Giannoudis PV. Sacral fractures: issues, challenges, solutions. EFORT Open Rev 2020;5:299-311. [Crossref] [PubMed]
9. Denis F, Davis S, Comfort T. Sacral fractures: an important problem. Retrospective analysis of 236 cases. Clin Orthop Relat Res 1988;67-81.
10. Hofmann A, Wagner D, Rommens PM. Iliosacral screw osteosynthesis - state of the art. Arch Orthop Trauma Surg 2025;145:122. [Crossref] [PubMed]
11. Routt ML Jr, Kregor PJ, Simonian PT, et al. Early results of percutaneous iliosacral screws placed with the patient in the supine position. J Orthop Trauma 1995;9:207-14. [Crossref] [PubMed]
12. Husband Z, Kromberg E, Lange A, et al. Strategies and Safety in Iliosacral Screw Placement. The Journal of the American Osteopathic Academy of Orthopedics 2024; [Crossref]
13. Hadeed MM, Woods D, Koerner J, et al. Risk factors for screw breach and iatrogenic nerve injury in percutaneous posterior pelvic ring fixation. J Clin Orthop Trauma 2022;33:101994. [Crossref] [PubMed]
14. Tonetti J, Boudissa M, Kerschbaumer G, et al. Role of 3D intraoperative imaging in orthopedic and trauma surgery. Orthop Traumatol Surg Res 2020;106:S19-25. [Crossref] [PubMed]
15. Florio M, Capasso L, Olivi A, et al. 3D - Navigated percutaneous screw fixation of pelvic ring injuries - a pilot study. Injury 2020;51:S28-33. [Crossref] [PubMed]
16. Lu S, Yang K, Lu C, et al. O-arm navigation for sacroiliac screw placement in the treatment for posterior pelvic ring injury. Int Orthop 2021;45:1803-10. [Crossref] [PubMed]
17. Chaves JPG, Maalouly J, Choi JYS. Clinical results following robotic navigation guidance for sacroiliac joint fusion in 36 patients. Neurosurg Focus 2022;52:E6. [Crossref] [PubMed]
18. Glenister R, Sharma S. Anatomy, Bony Pelvis and Lower Limb, Hip. In: StatPearls. Treasure Island (FL): StatPearls Publishing; 2025.
19. Qu H, Guo W. Surgical Anatomy of the Sacrum. In: Guo W, Hornicek FJ, Sim FH, editors. Surgery of the Pelvic and Sacral Tumor. Dordrecht: Springer Netherlands; 2020:165-7.
20. Hammer N, Steinke H, Lingslebe U, et al. Ligamentous influence in pelvic load distribution. Spine J 2013;13:1321-30. [Crossref] [PubMed]
21. Osterhoff G, Ossendorf C, Wanner GA, et al. Percutaneous iliosacral screw fixation in S1 and S2 for posterior pelvic ring injuries: technique and perioperative complications. Arch Orthop Trauma Surg 2011;131:809-13. [Crossref] [PubMed]
22. Salazar D, Lannon S, Pasternak O, et al. Investigation of bone quality of the first and second sacral segments amongst trauma patients: concerns about iliosacral screw fixation. J Orthop Traumatol 2015;16:301-8. [Crossref] [PubMed]
23. Prost M, Taday R, Beyersdorf CCP, et al. Navigation versus fluoroscopy in minimalinvasive iliosacral screw placement. J Orthop Surg Res 2024;19:185. [Crossref] [PubMed]
24. Kuttner H, Benninger E, Fretz V, et al. Fluoroscopy-guided vs. navigated iliosacral screw placement with intraoperative 3D scan or postoperative CT control: Impact of the clinical workflow on patients’ radiation exposure. Injury 2022;53:3764-8. [Crossref] [PubMed]
25. Theologis AA, Burch S, Pekmezci M. Placement of iliosacral screws using 3D image-guided (O-Arm) technology and Stealth Navigation: comparison with traditional fluoroscopy. Bone Joint J 2016;98-B:696-702. [Crossref] [PubMed]
26. Zwingmann J, Südkamp NP, König B, et al. Intra- and postoperative complications of navigated and conventional techniques in percutaneous iliosacral screw fixation after pelvic fractures: Results from the German Pelvic Trauma Registry. Injury 2013;44:1765-72. [Crossref] [PubMed]
27. Boudissa M, Carmagnac D, Kerschbaumer G, et al. Screw misplacement in percutaneous posterior pelvic iliosacral screwing with and without navigation: A prospective clinical study of 174 screws in 127 patients. Orthop Traumatol Surg Res 2022;108:103213. [Crossref] [PubMed]
28. Berger-Groch J, Lueers M, Rueger JM, et al. Accuracy of navigated and conventional iliosacral screw placement in B- and C-type pelvic ring fractures. Eur J Trauma Emerg Surg 2020;46:107-13. [Crossref] [PubMed]
29. Dea N, Fisher CG, Batke J, et al. Economic evaluation comparing intraoperative cone beam CT-based navigation and conventional fluoroscopy for the placement of spinal pedicle screws: a patient-level data cost-effectiveness analysis. Spine J 2016;16:23-31. [Crossref] [PubMed]
30. Yin Y, Hou Z, Zhang R, et al. Percutaneous Placement of Iliosacral Screws Under the Guidance of Axial View Projection of the S1 Pedicle: a Case Series. Sci Rep 2017;7:7925. [Crossref] [PubMed]
31. Wenning KE, Yilmaz E, Schildhauer TA, et al. Comparison of lumbopelvic fixation and iliosacral screw fixation for the treatment of bilateral sacral fractures. J Orthop Surg Res 2021;16:604. [Crossref] [PubMed]
32. Matson DM, Maccormick LM, Sembrano JN, et al. Sacral Dysmorphism and Lumbosacral Transitional Vertebrae (LSTV) Int J Spine Surg 2020;14:14-9. Review. [Crossref] [PubMed]
33. Kaiser SP, Gardner MJ, Liu J, et al. Anatomic Determinants of Sacral Dysmorphism and Implications for Safe Iliosacral Screw Placement. J Bone Joint Surg Am 2014;96:e120. [Crossref] [PubMed]
34. Khan JM, Lara DL, Marquez-Lara A, et al. Intraoperative CT and Surgical Navigation for Iliosacral Screws: Technique for Patients With Sacral Dysmorphism. J Orthop Trauma 2018;32:S24-5. [Crossref] [PubMed]
35. Wendt H, Gottschling H, Schröder M, et al. Recommendations for iliosacral screw placement in dysmorphic sacrum based on modified in-out-in corridors. J Orthop Res 2019;37:689-96. [Crossref] [PubMed]
36. Mendel T, Radetzki F, Wohlrab D, et al. CT-based 3-D visualisation of secure bone corridors and optimal trajectories for sacroiliac screws. Injury 2013;44:957-63. [Crossref] [PubMed]
37. Yin Y, Zhang R, Li S, et al. Computational analysis on the feasibility of transverse iliosacral screw fixation for different sacral segments. Int Orthop 2019;43:1961-7. [Crossref] [PubMed]
38. Mendel T, Noser H, Kuervers J, et al. The influence of sacral morphology on the existence of secure S1 and S2 transverse bone corridors for iliosacroiliac screw fixation. Injury 2013;44:1773-9. [Crossref] [PubMed]
39. Ramadanov N, Zabler S. Ramadanov-Zabler Safe Zone for Sacroiliac Screw Placement: A CT-Based Computational Pilot Study. J Clin Med 2025;14:3567. [Crossref] [PubMed]