Abstract
The aim of this cadaver study is to define the anatomic structures on anterior sacrum, which are under the risk of injury during bicortical screw application to the S1 and S2 pedicles. Thirty formaldehyde-preserved human male cadavers were studied. Posterior midline incision was performed, and soft tissues and muscles were dissected from the posterior part of the lumbosacral region. A 6 mm pedicle screw was inserted between the superior facet of S1 and the S1 foramen. The entry point of the S2 pedicle screw was located between S1 and S2 foramina. S1 and S2 screws were placed on both right and the left sides of all cadavers. Then, all cadavers were turned into supine position. All abdominal and pelvic organs were moved away and carefully observed for any injury. The tips of the sacral screws were marked and the relations with the anatomic structures were defined. The position of the sacral screws relative to the middle and lateral sacral arteries and veins, and the sacral sympathetic trunk were measured. There was no injury to the visceral organs. In four cases, S1 screw tip was in direct contact with middle sacral artery. In two cases, S1 screw tip was in direct contact with middle sacral vein. It was observed that the S1 screw tips were in close proximity to sacral sympathetic trunk on both right and the left sides. The tip of the S2 screw was in contact with middle sacral artery on the left side only in one case. It is found that the tip of the S2 screw was closely located with the middle sacral vein in two cases. The tip of the S2 pedicle screw was in contact with the sacral sympathetic trunk in eight cases on the right side and seven cases on the left side. Lateral sacral vein was also observed to be disturbed by the S1 and S2 screws. As a conclusion, anterior cortical penetration during sacral screw insertion carries a risk of neurovascular injury. The risk of sacral sympathetic trunk and minor vascular structures together with the major neurovascular structures and viscera should be kept in mind.
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References
Ebraheim NA, Lu J, Yang H, Heck BE, Yeasting RA (1997) Anatomic considerations of the second sacral vertebra and dorsal screw placement. Surg Radiol Anat 19:353–357
Ebraheim NA, Haman SP, Xu R, Stanescu S, Yeasting RA (2000) The lumbosacral nerves in relation to dorsal S1 screw placement and their locations on plain radiographs. Orthopedics 23(3):245–247
Emami A, Deviren V, Berven S, Smith JA, Hu SS, Bradford DS (2002) Outcome and complications of long fusions to the sacrum in adult spine deformity. Spine 27(7):776–786
Esenkaya I, Aluclu MA, Kavakli A, Bulut HT (2003) Radiologic and morphologic evaluation of the lateral sacral mass. Acta Orthop Traumatol Turc 37(4):330–339
Esses SI, Botsford DJ, Huler RJ, Rauschning W (1991) Surgical anatomy of the sacrum A guide for rational screw fixation. Spine 16(6 Suppl):S283–S288
Jutte PC, Castelein RM (2002) Complications of pedicle screws in lumbar and lumbosacral fusions in 105 consecutive primary operations. Eur Spine J 11(6):594–98
Kaptanoglu E, Okutan O, Tekdemir I, Beskonaklı E, Deda H (2003) Closed posterior superior iliac spine impending pediculocorporeal S-1 screw insertion. J Neurosurg (Spine 2) 99:229–234
Krag MH (1991) Biomechanics of thoracolumbar spinal fixation. A review. Spine 16(3 Suppl):S84–S99
Lebwohl NH, Cunningham BW, Dmitriev A, Shimamoto N, Gooch L, Devlin V, Boachie-Adjei O, Wagner TA (2002) Biomechanical comparison of lumbosacral fixation techniques in a calf spine model. Spine 27(21):2312–2320
Lehman RA, Kuklo TR, Belmont PJ, Andersen RC, Polly DW (2002) Advantage of pedicle screw fixation directed into the apex of the sacral promontory over bicortical fixation. Spine 27(8):806–811
Leong JCY, Lu WW, Zheng Y, Zhu Q, Zhong S (1998) Comparison of the strenghts of lumbosacral fixation achieved with techniques using one and two triangulated sacral screws. Spine 23(21):2289–2294
Licht NJ, Rowe DE, Ross LM (1992) Pitfalls of pedicle screw fixation in the sacrum. Spine 17(8):892–896
Louis R (1986) Fusion of the lumbar and sacral spine by internal fixation with screw plates. Clin Orthop Feb(203):18–33
Luk KDK, Chen L, Lu WW (2005) A stronger bicortical sacral pedicle screw fixation through the S1 endplate. Spine 30(5):525–529
Mirkovic S, Abitbol JJ, Steinman J, Edwards CC, Schaffler M, Massie J, Garfin SR (1991) Anatomic consideration for sacral screw placement. Spine 16(6 Suppl):S289–S294
Morse BJ, Ebraheim NA, Jackson WT (1994) Preoperative CT determination of angles for sacral screw placement. Spine 19(5):604–7
Roy-Camille R, Saillant G, Mazel G (1986) Internal fixation of the lumbar spine with pedicle screw plating. Clin Orthop Feb(203):7–17
Ruland CM, McAfee PC, Warden KE, Cunningham BW (1991) Triangulation of pedicular instrumentation. A biomechanical analysis. Spine 16(6 Suppl):S270–S276
Xu R, Ebraheim NA, Yeasting RA, Wong FY, Jackson WT (1995) Morphometric evaluation of the first sacral vertebra and the projection of its pedicle on the posterior aspect of the sacrum. Spine 20(8):936–40
Zindrick MR, Wiltse LL, Widell EH, Thomas JC, Holland WR, Field BT, Spencer CW (1986) A biomechanical study of intrapeduncular screw fixation in the lumbosacral spine. Clin Orthop Feb(203):99–112
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Ergur, I., Akcali, O., Kiray, A. et al. Neurovascular risks of sacral screws with bicortical purchase: an anatomical study. Eur Spine J 16, 1519–1523 (2007). https://doi.org/10.1007/s00586-007-0326-x
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DOI: https://doi.org/10.1007/s00586-007-0326-x