• Tomohiro Yamada, Tomohiko Hasegawa, Yu Yamato, Go Yoshida, Tomohiro Banno, Hideyuki Arima, Shin Oe, Yuki Mihara, Hiroki Ushirozako, Koichiro Ide, Yuh Watanabe, Keiichi Nakai, Kenta Kurosu, and Yukihiro Matsuyama.
• Department of Orthopedic Surgery, Hamamatsu University School of Medicine, 1-20-1, Handayama, Higashi-ku, Hamamatsu City, Shizuoka, 431-3192, Japan. cordial27@gmail.com.
• Arch Orthop Trauma Surg. 2023 Apr 1; 143 (4): 186118671861-1867.

PurposeThis study aimed to estimate the accuracy of pedicle screw (PS) placement in degenerative scoliosis surgery, characterize a patient population with PS misplacement, and analyze the association between misplaced PS vector and lumbar coronal curve.MethodsIn this study, 122 patients (average age 68.6 years), who underwent corrective and decompression surgery, were selected retrospectively. PS accuracy was evaluated in the thoracic to lumbar spine. We identified characteristics of misplacement in each patient. Screw positions were categorized into grade A, entirely in the pedicle; grade B, < 2 mm breach; grade C, 2-4 mm breach; and grade D, > 4 mm breach using postoperative computed tomography.ResultsThe mean preoperative lumbar coronal curve was 32.3 ± 18.4°, and the number of fused vertebrae was 8.9 ± 2.8. A total of 2032 PS were categorized as follows: grade A, 1897 PS (93.3%); grade B, 67 (3.3%); grade C, 26 (1.3%); and grade D, 43 (2.1%). One PS (grade D), inserted at T5, needed surgery for removal due to neurological deficit. The misplacement group (grades C and D) had a significantly stronger lumbar coronal curve and apical vertebral rotation than the accuracy group (grades A and B). Misplaced PS vector (direction and degree) was significantly correlated with inserted vertebral rotation. Grade D misplacement was distributed mainly around the transitional vertebra of the lumbar curve.ConclusionsThe accuracy of PS insertion in the thoracic to lumbar spine was high in DS surgery, but the need for care was highlighted in the transitional vertebra.© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.

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