Aplicación de tornillos transpediculares en la columna torácica: Descripción de la zona de seguridad según los hallazgos anatómicos en la población colombiana

Abstract

Introduction: After the introduction of the pedicle screws had been made, several techniques were described for placing them looking for a suitable and reproducible positioning of the implant, in order to consequently reduce the inherent risks in their application. This article describes the anatomical features of the thoracic pedicles in cadaveric sample. It also describes the benefits and risks involved in the use of pedicle screws along the thoracic spine, and furthermore a safety zone for placing pedicle screws by using the so called “freehand technique”.
Methods: Cadaveric dissection was performed in 92 isolated human thoracic pedicles from T4 to T12. Main objective was to perform a detailed description of height, width and length, of the pedicle according to their laterality and level. Each vertebra and soft tissues in association with the pedicle were removed from their anatomical location. We performed a pedicle screw placement in all thoracic segments studied, by evaluating pedicle level, position and orientation of the screws.
Results: There is variation in the orientation and shape of the pedicles according to anatomical location when analyzing both length and diameter of the pedicle. We found average lengths of 10.7 mm, with 7.5 mm cephalocaudal diameter and transverse diameter of 5 mm. Regarding the freehand technique, typical measurable changes of thoracic segment are important for proper pedicle screw instrumentation.
Discussion: An adequate knowledge of thoracic pedicle anatomy minimizes the risks inherent to a surgical technique. A description of a proposed safety zone for freehand placement of transpedicular screws in thoracic spine levels in Colombian population is included here in.