Abstract
Purpose
The rotation or translation of vertebrae in adolescent idiopathic scoliosis (AIS) patients could cause the relative migrations of surrounding vital structures and lead to smaller safe zones for pedicle screw insertion. This study aimed to determine the changed relative position of trachea to spine in the proximal thoracic curve (T1–T4) and to analyze the potential risks of tracheal injuries from pedicle screw insertions in AIS patients.
Methods
Twenty-three patients with complete proximal thoracic curve (CPT group), 25 patients with fractional proximal thoracic curve (FPT group) and 19 normal subjects with a straight spine (normal group) were included. Axial computed tomography images from T1 to T4 level were obtained to evaluate trachea–vertebral distance (TVD, the closest distance between trachea and vertebral body) and trachea–vertebral angle (TVA, defined as 0° when the trachea was located directly laterally to the left and 180° when directly laterally to the right). The extension line of pedicle axis could cross the anterior wall of vertebra and the posterior wall of the trachea at two points when the trachea was located in the trajectory of the screw passage. If the distance between the two points was less than 5 mm, the trachea was considered to be at a potential risk of injury. The percentages of vulnerable trachea were calculated at each level.
Results
The TVA in the CPT group was significantly larger than that in the FPT group and in the normal group, while the TVA in the FPT group was significantly larger than that in the normal group at the T2–T4 level. The TVD in the FPT group was significantly smaller than that in the CPT group and in the normal group at each level, while the TVD in the CPT group was significantly smaller than that in the normal group at the T2 and T3 levels. No trachea was found to be at risk from screw insertion on both sides in both the CPT group and the normal group. However, it was at a high risk of injury from anterior cortex penetration during right screw insertion in the FPT group. The percentage of trachea at risk from right screw insertion was 40 % at T1 level, 92 % at T2 level, 100 % at both T3 and T4 levels.
Conclusions
This CT-based study demonstrates that the FPT curve has a smaller safe zone with respect to tracheal injury during screw insertion. Spine surgeons should choose the appropriate screw length to avoid anterior wall perforation.
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References
Cardoso MJ, Helgeson MD, Paik H, Dmitriev AE, Lehman RA Jr, Rosner MK (2010) Structures at risk from pedicle screws in the proximal thoracic spine: computed tomography evaluation. Spine J 10:905–909
Di Silvestre M, Bakaloudis G, Lolli F, Vommaro F, Martikos K, Parisini P (2008) Posterior fusion only for thoracic adolescent idiopathic scoliosis of more than 80 degrees: pedicle screws versus hybrid instrumentation. Eur Spine J 17:1336–1349
Ebraheim NA, Jabaly G, Xu R, Yeasting RA (1997) Anatomic relations of the thoracic pedicle to the adjacent neural structures. Spine (Phila Pa 1976) 22:1553–1556 (discussion 1557)
Guo X, Chau WW, Chan YL, Cheng JC (2003) Relative anterior spinal overgrowth in adolescent idiopathic scoliosis. Results of disproportionate endochondral-membranous bone growth. J Bone Joint Surg Br 85:1026–1031
Hicks JM, Singla A, Shen FH, Arlet V (2010) Complications of pedicle screw fixation in scoliosis surgery: a systematic review. Spine (Phila Pa 1976) 35:E465–E470
Ilharreborde B, Even J, Lefevre Y, Fitoussi F, Presedo A, Souchet P, Pennecot GF, Mazda K (2008) How to determine the upper level of instrumentation in Lenke types 1 and 2 adolescent idiopathic scoliosis: a prospective study of 132 patients. J Pediatr Orthop 28:733–739
Jiang J, Mao S, Zhao Q, Liu Z, Qian B, Zhu F, Qiu Y (2012) Different proximal thoracic curve patterns have different relative positions of esophagus to spine in adolescent idiopathic scoliosis: a computed tomography study. Spine (Phila Pa 1976) 37:193–199
Krismer M, Bauer R, Sterzinger W (1992) Scoliosis correction by Cotrel–Dubousset instrumentation. The effect of derotation and three dimensional correction. Spine (Phila Pa 1976) 17:S263–S269
Kuklo TR, Lehman RA Jr, Lenke LG (2005) Structures at risk following anterior instrumented spinal fusion for thoracic adolescent idiopathic scoliosis. J Spinal Disord Tech 18(Suppl):S58–S64
Kuklo TR, Lenke LG, Graham EJ, Won DS, Sweet FA, Blanke KM, Bridwell KH (2002) Correlation of radiographic, clinical, and patient assessment of shoulder balance following fusion versus nonfusion of the proximal thoracic curve in adolescent idiopathic scoliosis. Spine (Phila Pa 1976) 27:2013–2020
Kuklo TR, Lenke LG, O’Brien MF, Lehman RA Jr, Polly DW Jr, Schroeder TM (2005) Accuracy and efficacy of thoracic pedicle screws in curves more than 90 degrees. Spine (Phila Pa 1976) 30:222–226
Kuklo TR, Potter BK, Schroeder TM, O’Brien MF (2006) Comparison of manual and digital measurements in adolescent idiopathic scoliosis. Spine (Phila Pa 1976) 31:1240–1246
Lamartina C, Petruzzi M, Macchia M, Stradiotti P, Zerbi A (2011) Role of rod diameter in comparison between only screws versus hooks and screws in posterior instrumentation of thoracic curve in idiopathic scoliosis. Eur Spine J 20(Suppl 1):S85–S89
Li G, Lv G, Passias P, Kozanek M, Metkar US, Liu Z, Wood KB, Rehak L, Deng Y (2010) Complications associated with thoracic pedicle screws in spinal deformity. Eur Spine J 19:1576–1584
Rose PS, Lenke LG (2007) Classification of operative adolescent idiopathic scoliosis: treatment guidelines. Orthop Clin North Am 38:521–529
Samdani AF, Ranade A, Sciubba DM, Cahill PJ, Antonacci MD, Clements DH, Betz RR (2010) Accuracy of free-hand placement of thoracic pedicle screws in adolescent idiopathic scoliosis: how much of a difference does surgeon experience make? Eur Spine J 19:91–95
Sarlak AY, Buluc L, Sarisoy HT, Memisoglu K, Tosun B (2008) Placement of pedicle screws in thoracic idiopathic scoliosis: a magnetic resonance imaging analysis of screw placement relative to structures at risk. Eur Spine J 17:657–662
Sarlak AY, Tosun B, Atmaca H, Sarisoy HT, Buluc L (2009) Evaluation of thoracic pedicle screw placement in adolescent idiopathic scoliosis. Eur Spine J 18:1892–1897
Upasani VV, Tis J, Bastrom T, Pawelek J, Marks M, Lonner B, Crawford A, Newton PO (2007) Analysis of sagittal alignment in thoracic and thoracolumbar curves in adolescent idiopathic scoliosis: how do these two curve types differ? Spine (Phila Pa 1976) 32:1355–1359
Vaccaro AR, Rizzolo SJ, Balderston RA, Allardyce TJ, Garfin SR, Dolinskas C, An HS (1995) Placement of pedicle screws in the thoracic spine. Part II: an anatomical and radiographic assessment. J Bone Joint Surg Am 77:1200–1206
Acknowledgment
The authors would like to acknowledge the Natural Science Foundation of Jiangsu Province, China (BK2011092).
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B. Qian and J. Jiang contributed equally to this work.
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Qian, B., Jiang, J., Zhu, F. et al. How is the trachea at risk of injury from pedicle screw insertion in proximal thoracic curve of adolescent idiopathic scoliosis patients?. Eur Spine J 22, 338–344 (2013). https://doi.org/10.1007/s00586-012-2520-8
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DOI: https://doi.org/10.1007/s00586-012-2520-8