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. 2025 Sep 19.
doi: 10.1007/s43390-025-01160-6. Online ahead of print.

Defining anatomical landmarks for simulated juxtapedicular screw placement for posterior spinal fusion in adolescent patients with scoliosis

Adam A Jamnik  1 , Sarah Pirkle  2 , Dennis P Devito  3 , Joshua S Murphy  3 , Brandon A Ramo  4 , Nicholas D Fletcher  5
Affiliations

Defining anatomical landmarks for simulated juxtapedicular screw placement for posterior spinal fusion in adolescent patients with scoliosis

Adam A Jamnik et al. Spine Deform. .

Abstract

Purpose: To define anatomical landmarks on the vertebrae at each spinal level for surgeons to use intraoperatively as a guide for the placement of juxtapedicular screws in the setting of hypoplastic or absent pedicles.

Methods: Preoperative computed tomography (CT) of patients with adolescent idiopathic scoliosis (AIS) was analyzed for thoracic pedicles ≤ 3 mm wide, measured between the outer cortices at the isthmus, as these may require a juxtapedicular screw for safe placement. For these pedicles, a simulated juxtapedicular screw was placed into the vertebrae using image reconstruction software. The distance from the screw's insertion point was measured in the axial plane to the medial and lateral borders of the superior articular process (SAP) and to the posterior tip of the transverse process (TP), and in the sagittal plane to the junction of the SAP and TP. Screw trajectory angle was measured between the longitudinal axis of the screw and the sagittal and axial planes.

Results: Of 6324 pedicles, a total of 378 pedicles (6.0%) met inclusion. The average distance to the medial and lateral borders of the SAP was 14.7 ± 3.4 mm and 10.7 ± 5.4 mm, respectively; to the tip of the TP was 9.0 ± 3.9 mm, and to the TP/SAP junction 2.8 ± 1.6 mm. The average angle in the axial plane was 21.1 ± 4.4° and in the sagittal plane it was - 4.2 ± 3.6°.

Conclusions: Preoperative CT scans were used to map a safe starting point and trajectory for juxtapedicular screw placement in thoracic vertebrae. These findings can assist surgeons with thoracic pedicle screw placement.

Keywords: Adolescent idiopathic scoliosis; CT image reconstruction; Juxtapedicular screws; Pedicle screws; Posterior spinal fusion.

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Conflict of interest statement

Declarations. Conflict of interest: DD: consultant—Alphatec Spine, Medtronic, SeaSpine, IP Royalties— Medtronic, SeaSpine. JM: consultant—Depuy Synthes Spine, ATEC Spine, Orthopediatrics. Grant support—POSNA. BR: no conflicts of interest. NDF: consultant—Medtronic Spine. Speakers Bureau—Orthopediatrics, Medtronic Spine. Grant support—1998 Society, Harrison Foundation, SRS via Setting Scoliosis Straight. Board positions—CHOA 1998 Society, POSNA board.

References

    1. Watanabe K, Lenke LG, Matsumoto M, Harimaya K, Kim YJ, Hensley M, Stobbs G, Toyama Y, Chiba K (2010) A novel pedicle channel classification describing osseous anatomy. Spine (Phila Pa 1976) 35:1836–1842 - DOI - PubMed
    1. Parent S, Labelle H, Skalli W, Latimer B, de Guise J (2002) Morphometric analysis of anatomic scoliotic specimens. Spine (Phila Pa 1976) 27:2305–2311 - DOI - PubMed
    1. Esses SI, Sachs BL, Dreyzin V (1993) Complications associated with the technique of pedicle screw fixation. A selected survey of ABS members. Spine (Phila Pa 1976) 18:2231–2238 (discussion 2238-9) - DOI - PubMed
    1. Hicks JM, Singla A, Shen FH, Arlet V (2010) Complications of pedicle screw fixation in scoliosis surgery. Spine (Phila Pa 1976) 35:E465–E470 - DOI - PubMed
    1. Parker SL, Amin AG, Santiago-Dieppa D, Liauw JA, Bydon A, Sciubba DM, Wolinsky J-P, Gokaslan ZL, Witham TF (2014) Incidence and clinical significance of vascular encroachment resulting from freehand placement of pedicle screws in the thoracic and lumbar spine: analysis of 6816 consecutive screws. Spine (Phila Pa 1976) 39:683–687 - DOI - PubMed

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