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. 2016 Mar 9;6(1):e9. doi: 10.2106/JBJS.ST.N.00114

Placement of Thoracic Pedicle Screws

David W Polly Jr 1, Alexandra K Yaszemski 1, Kristen E Jones 1
PMCID: PMC6145610  PMID: 30237919

Abstract

Thoracic pedicle screws have become the spinal anchor of choice because of the superior biomechanics of this technique. It is widely used for the treatment of scoliosis, spinal deformity (such as kyphosis), trauma, tumors, infection, and other pathologies. The technique demands precision as malposition can result in spinal cord or visceral injury with potential catastrophic consequences (death or paralysis).

There have been many published articles looking at the anatomy and the anatomic variation in various populations according to race, age, deformity, etc. Lenke and others have developed start point guidelines that seem to have reasonable validity.

There are two basic screw trajectories:

  1. The straightforward technique.

  2. The anatomic trajectory.

The straightforward technique parallels the superior end plate of the instrumented vertebra. It has the best insertional torque. The anatomic trajectory bisects the sagittal axis of the pedicle, typically 15° cranial to caudal, and has the largest available bone channel. The accuracy of placement is a debated topic. There are several meta-analyses and systematic reviews that address this question. However, there are a variety of definitions of acceptable compared with optimal placement. The current gold standard for judging screw placement is the use of computed tomography; however, it carries a substantial radiation burden to the patient, which must be considered.

There are a myriad of described techniques, including freehand (anatomically based), fluoroscopy-guided, and three-dimensional (3-D) image-guided methods. All have their advantages and disadvantages. Surgeons must find the technique that is safe and reliable in their hands.

The procedure is performed with the following steps:

  1. Preoperative planning is done by initially looking at plain radiographs and by assessing bending radiographs and preoperative computed tomography scans, if available.

  2. The patient is placed on a Jackson table, which is radiolucent and allows easy access for C-arm or O-arm technology.

  3. Locate the start point around the thoracic level (T12, T8, etc.); a review of the Lenke start point map is helpful.

  4. Create the dorsal cortical hole, which is best done with a small pilot hole; we recommend the use of a 3-mm high-speed burr (Midas Rex; Medtronic).

  5. Create a track within the pedicle by probing with either a navigated probe or a Lenke-style freehand probe.

  6. Confirm the accuracy of the screw tract placement, which can be done by palpation although it is not 100% reliable.

  7. Place the screw after tapping 1 mm less than the nominal screw diameter.

  8. Confirm the accuracy of screw placement with fluoroscopy or plain radiographs; 3-D intraoperative imaging is the most reliable technique, but it also exposes the patient to the most radiation.

  9. Confirm the neurological status of the patient by monitoring the motor evoked potential signals after screw placement.

  10. Close the wound after the screws have been checked with intraoperative 2-D or 3-D imaging to ensure that they have not cut or plowed out.

The results of thoracic pedicle screw placement are specific to the spinal condition treated. For adolescent idiopathic scoliosis, no brace is needed and walking can be progressed as tolerated. With good thoracic screw placement, rehabilitation typically is accelerated because a stable spinal construct is achieved. Most patients are able to walk without any sort of external mobilization or special adjunctive protection.

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Acknowledgments

Note: The chart entitled “Pedicle Screw Starting Points for the Straight-Forward Trajectory” by Lawrence G. Lenke, MD, from the CD Horizon Legacy Spinal System, was provided by Medtronic. Reproduced with permission.

Footnotes

Published outcomes of this procedure can be found at: Spine (Phila Pa 1976). 2003 Sep 15;28(18):2058-65, Spine (Phila Pa 1976). 2001 Nov 1;26(21):2340-6, and Spine J. 2014 Jan;14(1):137-44

Disclosure: None of the authors received payments or services, either directly or indirectly (i.e., via his or her institution), from a third party in support of any aspect of this work. None of the authors, or their institution(s), have had any financial relationship, in the thirty-six months prior to submission of this work, with any entity in the biomedical arena that could be perceived to influence or have the potential to influence what is written in this work. Also, no author has had any other relationships, or has engaged in any other activities, that could be perceived to influence or have the potential to influence what is written in this work. The complete Disclosures of Potential Conflicts of Interest submitted by authors are always provided with the online version of the article.

References

  • 1.de Kleuver M, Lewis SJ, Germscheid NM, Kamper SJ, Alanay A, Berven SH, Cheung KM, Ito M, Lenke LG, Polly DW, Qiu Y, van Tulder M, Shaffrey C. Optimal surgical care for adolescent idiopathic scoliosis: an international consensus. Eur Spine J. 2014. December;23(12):2603-18. Epub 2014 Jun 24. [DOI] [PubMed] [Google Scholar]
  • 2.Lehman RA, Jr, Kang DG, Lenke LG, Gaume RE, Paik H. The ventral lamina and superior facet rule: a morphometric analysis for an ideal thoracic pedicle screw starting point. Spine J. 2014. January;14(1):137-44. Epub 2013 Nov 20. [DOI] [PubMed] [Google Scholar]
  • 3.Larson AN, Polly DW, Jr, Guidera KJ, Mielke CH, Santos ER, Ledonio CG, Sembrano JN. The accuracy of navigation and 3D image-guided placement for the placement of pedicle screws in congenital spine deformity. J Pediatr Orthop. 2012. September;32(6):e23-9. [DOI] [PubMed] [Google Scholar]
  • 4.Cui G, Watanabe K, Hosogane N, Tsuji T, Ishii K, Nakamura M, Toyama Y, Chiba K, Lenke LG, Matsumoto M. Morphologic evaluation of the thoracic vertebrae for safe free-hand pedicle screw placement in adolescent idiopathic scoliosis: a CT-based anatomical study. Surg Radiol Anat. 2012. April;34(3):209-16. Epub 2011 Jul 8. [DOI] [PubMed] [Google Scholar]
  • 5.Larson AN, Santos ER, Polly DW, Jr, Ledonio CG, Sembrano JN, Mielke CH, Guidera KJ. Pediatric pedicle screw placement using intraoperative computed tomography and 3-dimensional image-guided navigation. Spine (Phila Pa 1976). 2012. February 1;37(3):E188-94. [DOI] [PubMed] [Google Scholar]
  • 6.Harimaya K, Lenke LG, Son-Hing JP, Bridwell KH, Schwend RM, Luhmann SJ, Koester LA, Sides BA. Safety and accuracy of pedicle screws and constructs placed in infantile and juvenile patients. Spine (Phila Pa 1976). 2011. September 15;36(20):1645-51. [DOI] [PubMed] [Google Scholar]
  • 7.Watanabe K, Lenke LG, Matsumoto M, Harimaya K, Kim YJ, Hensley M, Stobbs G, Toyama Y, Chiba K. A novel pedicle channel classification describing osseous anatomy: how many thoracic scoliotic pedicles have cancellous channels? Spine (Phila Pa 1976). 2010. September 15;35(20):1836-42. [DOI] [PubMed] [Google Scholar]
  • 8.Dhawan A, Klemme WR, Polly DW., Jr Thoracic pedicle screws: comparison of start points and trajectories. Spine (Phila Pa 1976). 2008. November 15;33(24):2675-81. [DOI] [PubMed] [Google Scholar]
  • 9.Kim YW, Lenke LG, Kim YJ, Bridwell KH, Kim YB, Watanabe K, Watanabe K. Free-hand pedicle screw placement during revision spinal surgery: analysis of 552 screws. Spine (Phila Pa 1976). 2008. May 1;33(10):1141-8. [DOI] [PubMed] [Google Scholar]
  • 10.Ofiram E, Polly DW, Gilbert TJ, Jr, Choma TJ. Is it safer to place pedicle screws in the lower thoracic spine than in the upper lumbar spine? Spine (Phila Pa 1976). 2007. January 1;32(1):49-54. [DOI] [PubMed] [Google Scholar]
  • 11.Kim YJ, Lenke LG. Thoracic pedicle screw placement: free-hand technique. Neurol India. 2005. December;53(4):512-9. [DOI] [PubMed] [Google Scholar]
  • 12.Lehman RA, Potter BK, Kuklo TR, Chang AS, Polly DW, Shawen SB, Orchowski JR. Probing for thoracic pedicle screw tract violation(s): is it valid? J Spinal Disord Tech. 2004. August;17(4):277-83. [DOI] [PubMed] [Google Scholar]
  • 13.Lehman RA, Jr, Polly DW, Jr, Kuklo TR, Cunningham B, Kirk KL, Belmont PJ., Jr Straight-forward versus anatomic trajectory technique of thoracic pedicle screw fixation: a biomechanical analysis. Spine (Phila Pa 1976). 2003. September 15;28(18):2058-65. [DOI] [PubMed] [Google Scholar]
  • 14.Belmont PJ, Jr, Klemme WR, Robinson M, Polly DW., Jr Accuracy of thoracic pedicle screws in patients with and without coronal plane spinal deformities. Spine (Phila Pa 1976). 2002. July 15;27(14):1558-66. [DOI] [PubMed] [Google Scholar]
  • 15.Belmont PJ, Jr, Klemme WR, Dhawan A, Polly DW., Jr In vivo accuracy of thoracic pedicle screws. Spine (Phila Pa 1976). 2001. November 1;26(21):2340-6. [DOI] [PubMed] [Google Scholar]
  • 16.O’Brien MF, Lenke LG, Mardjetko S, Lowe TG, Kong Y, Eck K, Smith D. Pedicle morphology in thoracic adolescent idiopathic scoliosis: is pedicle fixation an anatomically viable technique? Spine (Phila Pa 1976). 2000. September 15;25(18):2285-93. [DOI] [PubMed] [Google Scholar]

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