Quantification of the Upper and Second Sacral Segment Safe Zones in Normal and Dysmorphic Sacra
Department of Orthopaedic Surgery, Washington University School of Medicine, St. Louis, MO 63110, USA. Journal of orthopaedic trauma
(Impact Factor: 1.8).
10/2010; 24(10):622-9. DOI: 10.1097/BOT.0b013e3181cf0404
To quantify the obliquity and dimensions of the upper and second sacral segment iliosacral screw safe zones and to determine the differences between normal and dysmorphic sacral morphology.
University Level I trauma center.
Fifty patients with pelvic computed tomography scans.
All sacra were characterized as normal or dysmorphic based on plain pelvic radiographs and previously described criteria. Multiple computed tomography scan reconstructions were viewed and manipulated simultaneously with 6 degrees of freedom to allow for custom visualization in any plane.
In each patient, a unique reconstruction plane was created perpendicular to the safe zone axis. The narrowest safe zone cross-sectional area was measured. Next, on simulated pelvic outlet and inlet views, safe zone obliquity and width were measured. Finally, the space available for a transverse screw was assessed. Measurements were performed for both upper and second sacral segment. Values for normal and dysmorphic safe zones were compared.
Sacral dysmorphism was identified in 22 patients. In these sacra, the upper sacral segment safe zone cross-section was 36% smaller than in normal sacra (P < 0.001). No transverse screws could be placed, but accommodating for the caudal to cranial obliquity (30° versus 21° in normals, P < 0.001) and posterior to anterior obliquity (15% versus 4% in normals, P < 0.001) of the safe zone, an iliosacral screw at least 75 mm in length could be placed safely in 91% of patients. A transverse screw could be placed in 75% of normal sacra. In the second segment safe zone, the cross-sectional area was more than twice as large in dysmorphic sacra compared to normals (220 mm versus 109 mm, P < 0.001). The obliquity was not different on either the inlet or outlet views between groups. A transverse screw could be placed at this level in 95% of those with dysmorphic sacra and in only 50% of normal sacra.
Sacral dysmorphism occurred in 44% of patients in this consecutive series. Many anatomic differences were consistently found between the two morphologies with clinical relevance to iliosacral screw placement. Specifically, the dysmorphic upper sacral segment safe zone is significantly smaller and more obliquely oriented but is still large enough to accommodate an iliosacral screw in nearly all patients. The second sacral segment safe zone is approximately transversely oriented in both sacral types but is more than twice as large in dysmorphic sacra. This segment may be a primary fixation opportunity in patients with sacral dysmorphism.
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- "Furthermore , a study  shows that the S2 segment provides a larger osseous site for screw insertion than S1 in dysmorphic sacrums and the significantly longer screws are possible in S2 compared with the dysmorphic S1 segment. Another study also indicates that the S2 segment may be a primary fixation opportunity in patients with sacral dysmorphism . Combined with this mechanical study results, sacroiliac screw fixation in S2 is a good choice in the treatment of some unilateral vertical sacral fractures if technical conditions allow. "
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ABSTRACT: To compare the stability of lengthened sacroiliac screw and standard sacroiliac screw for the treatment of unilateral vertical sacral fractures; to provide reference for clinical applications.
A finite element model of Tile type C pelvic ring injury (unilateral Denis type II fracture of the sacrum) was produced. The unilateral sacral fractures were fixed with lengthened sacroiliac screw and sacroiliac screw in six different types of models respectively. The translation and angle displacement of the superior surface of the sacrum (in standing position on both feet) were measured and compared.
The stability of one lengthened sacroiliac screw fixation in S1 or S2 segment is superior to that of one sacroiliac screw fixation in the same sacral segment. The stability of one lengthened sacroiliac screw fixation in S1 and S2 segments respectively is superior to that of one sacroiliac screw fixation in S1 and S2 segments respectively. The stability of one lengthened sacroiliac screw fixation in S1 and S2 segments respectively is superior to that of one lengthened sacroiliac screw fixation in S1 or S2 segment. The stability of one sacroiliac screw fixation in S1 and S2 segments respectively is markedly superior to that of one sacroiliac screw fixation in S1 or S2 segment. The vertical and rotational stability of lengthened sacroiliac screw fixation and sacroiliac screw fixation in S2 is superior to that of S1.
In a finite element model of type C pelvic ring disruption, S1 and S2 lengthened sacroiliac screws should be utilized for the fixation as regularly as possible and the most stable fixation is the combination of the lengthened sacroiliac screws of S1 and S2 segments. Even if lengthened sacroiliac screws cannot be systematically used due to specific conditions, one sacroiliac screw fixation in S1 and S2 segments respectively is recommended. No matter which kind of sacroiliac screw is used, if only one screw can be implanted, the fixation in S2 segment is more recommended than that in S1.
Experimental study Level III.
Orthopaedics & Traumatology Surgery & Research 07/2013; 126(5). DOI:10.1016/j.otsr.2013.03.023 · 1.26 Impact Factor
Available from: Pol Maria Rommens
- "Better-adapted instruments and implants are needed in order to produce a fixation that is less invasive but as strong as what is currently available. In addition, a dysmorphic sacrum should be excluded preoperatively in the CT scan before the decision is made for transsacral bars or screws . "
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ABSTRACT: The number and variety of osteoporotic fractures of the pelvis are rapidly growing around the world. Such fractures are the result of low-impact trauma. The patients have no signs of hemodynamic instability and do not require urgent stabilization. The clinical picture is dominated by immobilizing pain in the pelvic region. Fractures may be located in both the ventral and the dorsal pelvic ring. The current well-established classification of pelvic ring lesions in younger adults does not fully reflect the criteria for osteoporotic and insufficiency fractures of the pelvic ring. Most osteoporotic fractures are minimally displaced and do not require surgical therapy. However, in some patients, an insidious progress of bone damage leads to complex displacement and instability. Therefore, vertical sacral ala fractures, fracture dislocations of the sacroiliac joint, and spinopelvic dissociations are best treated with operative stabilization. Angular stable bridge plating, the insertion of a transsacral positioning bar, and iliolumbar fixation are operative techniques that have been adapted to the low bone mineral density of the pelvic ring and the high forces acting on it.
European Journal of Trauma and Emergency Surgery 10/2012; 38(5):499-509. DOI:10.1007/s00068-012-0224-8 · 0.35 Impact Factor
Available from: Gregory A Schmale
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ABSTRACT: The treatment of physeal arrest after infection remains a challenge. This report describes localized endoscopic epiphysiolysis combined with guided growth in the treatment of partial physeal arrest and limb deformity in an infant after infection. Over a year's time, the valgus was corrected and the plate was removed. The patient returned to full activity. Physeal arrest may occur at anytime after physeal trauma, highlighting the importance of long-term follow-up. Endoscopic physeal bar takedown combined with guided growth of the distal femur can be an effective option for the treatment.
Journal of pediatric orthopaedics. Part B / European Paediatric Orthopaedic Society, Pediatric Orthopaedic Society of North America 04/2011; 21(4):348-51. DOI:10.1097/BPB.0b013e328346d308 · 0.59 Impact Factor
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