Tomographic Analysis of the Anatomical Parameters for the Insertion of Cortical Bone Screws

• Published in: Revista brasileira de ortopedia Vol. 57; no. 1; pp. 47 - 54
• Main Authors: Herrero, Carlos Fernando Pereira Silva, Marangoni, Rafael Campos Fróes
• Format: Journal Article
• Language: English; Portuguese
• Published: Germany Thieme Revinter Publicações Ltda 01.02.2022; Sociedade Brasileira de Ortopedia e Traumatologia
• Subjects: Artigos Originais; bone screws; minimally invasive surgical procedures; ORTHOPEDICS; spine; minimally invasive surgical procedures; spine; bone screws; parafusos ósseos; procedimentos cirúrgicos minimamente invasivos; coluna vertebral
• ISSN: 0102-3616; 1982-4378; 1982-4378
• DOI: 10.1055/s-0041-1731672

To study the parameters related to the insertion path of cortical screws and to describe this technique.  Computed tomography (CT) scans of 30 patients, as well as the measurements from the L1 to the L5 vertebrae, were studied. A second observer evaluated ten randomly-selected exams. The parameters studied included the lateral angle (LA) and the screw diameter (SD) as axial variables, and the cranial angle (CA) and screw length (SL) as sagittal variables.  We studied 15 male patients (mean age: 31.33 years) and 15 female patients (mean age: 32.01 years). The LA varied between 13.8° and 20.89°, with a tendency to increase in the proximal to distal direction. The CA varied from 17.5° to 24.9°, with a tendency to decrease in the caudal direction. The SD ranged from 2.3 mm to 7.2 mm, with a tendency to increase as we progressed from proximal to distal. The SL varied from 19 mm to 45 mm, with a tendency to decrease as we proceeded from proximal (L1) to distal (L5). No statistical difference was observed between the genders or in the interobserver agreement regarding the values studied when comparing the sides.  The path of insertion of the cortical screw shows a variation in different populations. Therefore, we recommend a preoperative imaging study to reduce the surgical risks related to the technique.