The lateral sacral triangle—A decision support for secure transverse sacroiliac screw insertion

Mendel, Thomas; Noser, Hansrudi; Wohlrab, David; Stock, Karsten; Radetzki, Florian

doi:10.1016/j.injury.2010.03.016

Cited by 56 publications

(56 citation statements)

References 20 publications

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“…The same is true for transsacral screw placement. Using a cylindrical-shaped volume for automatic measurement of the osseous corridor diameters does not respect the ovoidshaped osseous corridor at the level of the S1 vertebra and therefore represents only the maximum osseous corridor height, but not necessarily the larger corridor width [11,22,39], which could facilitate placement of an additional second screw in the same corridor [22].…”

Section: Discussionmentioning

confidence: 99%

“…With wider use of screw fixations in different positions in the posterior pelvic ring (iliosacral or transsacral), several morphologic variations were described and the terms ''dysplastic sacrum'' and ''sacral dysmorphism'' were introduced, however, there is lack of consensus regarding their definitions [2,4,7,22,29]. Routt et al [29] described five qualitative radiographic signs for sacral dysplasia based on pelvic-outlet and true lateral views, whereas quantitative parameters were described by others [17,22]. Kaiser et al [17] developed a sacral dysmorphic score based on coronal and axial angulation of the upper sacral segment.…”

Section: Discussionmentioning

confidence: 99%

“…Kaiser et al [17] developed a sacral dysmorphic score based on coronal and axial angulation of the upper sacral segment. Mendel et al [22] reported the lateral sacral triangle configuration in the lateral view. A triangle ratio of 1.5 (calculated by the quotient of the anterior height and width of the first sacral body) represents the boundary ratio for the prevalence of sacral dysmorphism, defined as transsacral corridors with a diameter less than 7.3 mm, unsuitable for screw placement.…”

Section: Discussionmentioning

confidence: 99%

“…The drawback of transsacral screw fixation is the difficult placement owing to the individual variable three-dimensional anatomic shape of the sacrum (sacral dysmorphism), with several neurovascular structures in close proximity to the osseous boundary (S1 corridor: L4 and L5 nerve route and internal iliac vessels above and in front of the sacral alar region; S1 nerve route and the residual nerve pairs in the spinal canal below and posterior; S2 corridor: S1 foramen with its nerve route above and S2 foramen with its nerve route below) [3,7,34]. Furthermore there is limited ability to see all relevant bony structures on the intraoperative two-dimensional fluoroscopic images [7,22,29,31,40]. The corridor for the oblique sacroiliac screw placement in the first vertebra has been investigated in different biomorphometric studies [2,7,8,16], but data for transverse transsacral screw placement at the level of S1 and S2 are limited owing to the small size of study groups, different exclusion criteria, or measurement techniques [11,22,23,37,39].…”

Section: Introductionmentioning

confidence: 99%

“…Furthermore there is limited ability to see all relevant bony structures on the intraoperative two-dimensional fluoroscopic images [7,22,29,31,40]. The corridor for the oblique sacroiliac screw placement in the first vertebra has been investigated in different biomorphometric studies [2,7,8,16], but data for transverse transsacral screw placement at the level of S1 and S2 are limited owing to the small size of study groups, different exclusion criteria, or measurement techniques [11,22,23,37,39].…”

Section: Introductionmentioning

confidence: 99%

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Transsacral Osseous Corridor Anatomy Is More Amenable To Screw Insertion In Males: A Biomorphometric Analysis of 280 Pelves

Gras

Gottschling

Schröder

et al. 2016

Clinical Orthopaedics &Amp; Related Research

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Background Percutaneous iliosacral screw placement is the standard procedure for fixation of posterior pelvic ring lesions, although a transsacral screw path is being used more frequently in recent years owing to increased fracture-fixation strength and better ability to fix central and bilateral sacral fractures. However, biomorphometric data for the osseous corridors are limited. Because placement of these screws in a safe and effective manner is crucial to using transsacral screws, we sought to address precise sacral anatomy in more detail to look for anatomic variation in the general population. Questions/purposes We asked: (1) What proportion of healthy pelvis specimens have no transsacral corridor at the level of the S1 vertebra owing to sacral dysmorphism? (2) If there is no safe diameter for screw placement in the transsacral S1 corridor, is an increased and thus safe diameter of the transsacral S2 corridor expected? (3) Are there sex-specific differences in sacral anatomy and are these correlated with known anthropometric parameters? Methods CT scans of pelves of 280 healthy patients acquired exclusively for medical indications such as polytrauma (20%), CT angiography (70%), and other reasons (10%), were segmented manually. Using an advanced CT-based image analysis system, the mean shape of all segmented pelves was generated and functioned as a template. On this template, the cylindric transsacral osseous corridor at the level of the S1 and S2 vertebrae was determined manually. Each pelvis then was registered to the template using a free-form registration algorithm to measure the maximum screw corridor diameters on each specimen semiautomatically. Results Thirty of 280 pelves (11%) had no transsacral S1 corridor owing to sacral dysmorphism. The average of maximum cylindrical diameters of the S1 corridor for the remaining 250 pelves was 12.8 mm (95% CI, 12.1-13.5 mm). A transverse corridor for S2 was found in 279 of 280 pelves, with an average of maximum cylindrical diameter of 11.6 mm (95% CI, 11.3-11.9 mm). Decreasing

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Transsacral Osseous Corridor Anatomy Is More Amenable To Screw Insertion In Males: A Biomorphometric Analysis of 280 Pelves

Gras

Gottschling

Schröder

et al. 2016

Clinical Orthopaedics &Amp; Related Research

View full text Add to dashboard Cite

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3D statistical modeling techniques to investigate the anatomy of the sacrum, its bone mass distribution, and the trans‐sacral corridors

Wagner

Kamer

Rommens³

et al. 2014

Journal Orthopaedic Research

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The complex anatomy of the sacrum makes surgical fracture fixation challenging. We developed statistical models to investigate sacral anatomy with special regard to trans-sacral implant fixation. We used computed tomographies of 20 intact adult pelves to establish 3D statistical models: a surface model of the sacrum and the trans-sacral corridor S1, including principal component analysis (PCA), and an averaged gray value model of the sacrum given in Hounsfield Units. PCA demonstrated large variability in sacral anatomy markedly affecting the diameters of the trans-sacral corridors. The configuration of the sacral alae and the vertical position of the auricular surfaces were important determinants of the trans-sacral corridor dimension on level S1. The statistical model of trans-sacral corridor S1 including the adjacent parts of the iliac bones showed main variation in length; however, the diameter was the main criterion for the surgically available corridor. The averaged gray value model revealed a distinct pattern of bone mass distribution with lower density particularly in the sacral alae. These advanced 3D statistical models provide a thorough anatomical understanding demonstrating the impact of sacral anatomy on positioning trans-sacral implants. The sacrum exhibits a complex anatomy that is critical for treating sacral fractures. This is especially true in percutaneous minimally invasive osteosynthesis using sacroiliac screws 1 or trans-sacral implants, 2,3 the latter being increasingly used in the treatment of sacral insufficiency fractures. 4 These fractures, occurring predominantly in osteoporotic patients, are isolated to the sacrum or a part of fragility fractures of the pelvic ring 5 and are typically located in the paraforaminal lateral region of the sacral ala. 6 Complex anatomy, reduced bone mass, and limited intraoperative visibility make adequate fixation difficult to achieve.Trans-sacral implants must be placed through safe intraosseous pathways, also termed trans-sacral corridors. They extend laterally from the ilium, traversing the sacroiliac joint, passing through the vertebral body on level S1 or S2 to reach the contralateral side of the sacrum and the ilium. These pathways are bordered anteriorly by the cortex of the anterior sacrum, posteriorly by the vertebral canal, and superiorly and inferiorly by the adjacent neural foramen. In S1, the superior border is formed by the sacral ala. 7 The entrance and exit points are located on the outer surface of the iliac bone. In contrast to safe pathways for sacroiliac screws reaching the vertebral body, trans-sacral corridors are more limited in their critical diameter, 8,9 exhibiting an oval shape. 7 Their 3D volume was previously computed in an automatic process. 7 The upper sacral anatomy was highly variable with up to 35% of the sacra called "dysmorphic" 10 providing only limited space to position implants on level S1. Surgical fracture fixation is further complicated by areas of different bone mass, especially in the osteoporotic, whe...

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Biomorphometric analysis of ilio‐sacro‐iliacal corridors for an intra‐osseous implant to fix posterior pelvic ring fractures

Gras

Hillmann

Rausch

et al. 2014

Journal Orthopaedic Research

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It is hypothesized that ilio-sacro-iliacal corridors for a new envisioned pelvic ring implant (trans-sacral nail with two iliacal bolts ¼ ISI-nail: ilio-sacro-iliacal nail) exists on the level of S1-or S2-vertebra in each patient. The corridors of 84 healthy human pelves (42x <; 42x ,, 18-85 years) were measured in high resolution CT scans using the Merlin Diagnostic Workcenter Software. Trans-sacral corridors (!9 mm diameter) on the level of S1 and S2 were found in 62% and 54% of pelves with a mean length [mm AE SD] of 164 AE 12.9 and 142 AE 10.2. Corresponding iliac corridors were present in all specimens in caudally tilted axial planes of 37.8 AE 0.67å nd 53.7 AE 0.94˚in relation to the operating table plane and divergent angulations of 69.0 AE 0.49˚and 70.1 AE 0.32˚in relation to the sagittal midline plane. Sacral dysmorphism, with compensatory larger S2 corridors were prevalent in 24% of pelves; ilio-sacro-iliacal osseous corridors for the envisioned implant were found in 88% of pelves on the level of S1 or S2. In the remaining 12% with too narrow corridors for any trans-sacral implant (screws, bars, ISI nail) alternative fixation methods have to be considered. Expected advantages of the envisioned ISI nail compared to available fixation devices are discussed. ß

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The lateral sacral triangle—A decision support for secure transverse sacroiliac screw insertion

Cited by 56 publications

References 20 publications

Transsacral Osseous Corridor Anatomy Is More Amenable To Screw Insertion In Males: A Biomorphometric Analysis of 280 Pelves

Transsacral Osseous Corridor Anatomy Is More Amenable To Screw Insertion In Males: A Biomorphometric Analysis of 280 Pelves

3D statistical modeling techniques to investigate the anatomy of the sacrum, its bone mass distribution, and the trans‐sacral corridors

Biomorphometric analysis of ilio‐sacro‐iliacal corridors for an intra‐osseous implant to fix posterior pelvic ring fractures

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