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Vol. 33. Issue 2.
Pages 71-81 (March - April 2022)
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Vol. 33. Issue 2.
Pages 71-81 (March - April 2022)
Clinical Research
Evaluation of the implantation of transpedicular screws in spinal instrumentation with free-hand technique and navigation-assisted with intraoperative computed tomography: An analytical-positional study
Evaluación de la implantación de tornillos transpediculares en instrumentación espinal con técnica free-hand y navegación asistida con tomografía computarizada intraoperatoria: un estudio analítico-posicional
Pedro Miguel González-Vargasa,b,
Corresponding author
, Lourdes Calero Félixa,b, Álvaro Martín-Gallegoa,b, José Luis Thenier-Villab,c, Adolfo Ramón de la Lama Zaragozaa,b, Cesáreo Conde Alonsoa,b
a Department of Neurosurgery, University Hospital Complex of Vigo, Pontevedra, Spain
b Neuroscience Research Group, Galicia Sur Health Research Institute, Vigo, Pontevedra, Spain
c Department of Neurosurgery, Hospital Universitari Arnau de Vilanova, Lleida, Spain
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Figures (2)
Tables (7)
Table 1. Demographic data on the study population.
Table 2. Screw distribution and pedicle rupture in the thoracic spine.
Table 3. Screw distribution and pedicle rupture in the lumbosacral spine.
Table 4. Demographic, anatomical and surgery-related patients’ data in groups A and B.
Table 5. Distribution of the screws regarding the conservation or not of the Safe Zone.
Table 6. Distribution of the groups according to the correct or not position of the screws.
Table 7. Surgical times and comparison of the two groups at three and six months of experience with intraoperative CT.
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Spinal instrumentation using transpedicular screws has been used for decades to stabilize the spine. In October 2018, an intraoperative CT system was acquired in the Neurosurgery service of the University Hospital Complex of Vigo, this being the first model of these characteristics in the Spanish Public Health System, so we began a study from January 2015 to December 2019 to assess the precision of the transpedicular screws implanted with this system compared with a control group performed with the classical technique and final fluoroscopic control.


The study was carried out in patients who required transpedicular instrumentation surgery, in total 655 screws were placed, 339 using the free-hand technique (Group A) and 316 assisted with intraoperative CT navigation (Group B) (p>0.05). Demographic characteristics, related to surgery and the screw implantation grades were assessed using the Gertzbein–Robbins classification.


92 patients were evaluated, between 12 and 86 years (average: 57.1 years). 161 thoracic screws (24.6%) and 494 lumbo-sacral screws (75.4%) were implanted. Of the thoracic screws, 33 produced a pedicle rupture. For the lumbo-sacral screws, 71 have had pedicle violation. The overall correct positioning rate for the free-hand group was 72.6% and for the CT group it was 96.5% (p<0.05).


The accuracy rate is higher in thoracic-lumbar instrumentation in the navigation group versus free-hand group with fluoroscopic control.

CT scan

La instrumentación espinal con tornillos transpediculares se ha utilizado durante décadas para estabilizar la columna. En octubre de 2018 se adquirió un sistema de TC intraoperatoria en el Servicio de Neurocirugía del Complejo Hospitalario Universitario de Vigo, siendo este, el primer modelo de estas características en el Sistema Público de Salud español, por lo que iniciamos un estudio desde enero de 2015 a diciembre de 2019 para evaluar la precisión de los tornillos transpediculares implantado con este sistema frente a un grupo control realizado con la técnica clásica y control fluoroscópico final.


Se realizó un estudio con pacientes que requirieron cirugía de instrumentación transpedicular, en total se colocaron 655 tornillos, 339 con la técnica free-hand (grupo A) y 316 asistidos con navegación por TC intraoperatoria (grupo B) (p>0,05). Se evaluaron las características demográficas relacionadas con la cirugía y los grados de implantación de tornillos según la clasificación de Gertzbein-Robbins.


Se evaluaron 92 pacientes, entre 12 y 86 años (promedio: 57,1 años). Se implantaron 161 tornillos torácicos (24,6%) y 494 tornillos lumbosacros (75,4%). De los tornillos torácicos, 33 produjeron una rotura pedicular. En el caso de los tornillos lumbosacros, 71 tuvieron violación pedicular. La tasa de correcto posicionamiento en general para el grupo free-hand fue del 72,6% y para el grupo de TC fue del 96,5% (p<0,05).


La tasa de precisión es mayor en la instrumentación torácica-lumbar en el grupo de navegación que en el grupo de manos libres con control fluoroscópico.

Palabras clave:
Tomografía computarizada


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