A new technique of pedicle screw placement with the use of sequential multilevel navigation templates based on patient-specific 3D CT reconstruction model: applicability in spine deformity.

INTRODUCTION: The technique of placement of pedicle screws has gradually improved, but even misplacement observed in 1.2 to 20% of cases, have appeared techniques fluoroscopic, tomographic and electromagnetic navigation, which led it to 1.3 to 4.3%, but nevertheless they are expensive and complex technologies. Present technique pedicle screw placement by using templates with a modification in the art, performing tomography and reconstruction in the same surgical position and with the templates of 3 or more levels. METHODS: Five cases of idiopathic scoliosis were performed, with correction and instrumentation with pedicular screws, where a three-dimensional model of the spine was performed with a tomography in a surgical position, whose images were exported to a 3D printer to reconstruct the desired trajectory of the screws in a template using cylinders resting on the inverse surface of the vertebrae. The direction of the screw was planned in the center of the pedicle and parallel to the upper platform of the vertebra. Each template was of several levels and transoperative X-rays were not used. RESULTS: Under electrophysiologic monitoring transoperative «red alerts¼ were not reported, the placement of the screws in postoperative CT scan was evaluated, showing a standard deviation in placement of 1.9 and 2.2 mm on the right and left respectively pedicles, with respect to their planning. DISCUSSION: This technique is simple and safe, besides not requiring great technology, its use is suggested in beginner spine surgeons and in severe deformities, it can be performed in any hospital where spinal surgery is performed.

INTRODUCCIÓN: La técnica de colocación de tornillos transpediculares ha mejorado paulatinamente, a pesar de ello, la mala colocación oscila entre 1.2 al 20% de los casos; han surgido técnicas de navegación asistidas por flouroscopía, tomografía y resonancia magnética mejorando el índice de falla al 1.3-4.3%. La presente técnica de colocación utiliza plantillas con la modificación de que la tomografía y la reconstrucción son realizadas con el paciente en la posición quirúrgica, además que las plantillas abarcan tres o más niveles. MÉTODOS: Se presentan cinco casos de escoliosis idiopática tratados con instrumentación y colocación de tornillos transpediculares donde se generó un modelo tridimensional de la columna en posición quirúrgica; las imágenes fueron exportadas a una impresora 3-D para reconstruir la trayectoria apropiada de los tornillos, la dirección de éstos fue planeada tomando de referencia el centro del pedículo y paralela a la plataforma superior de la vértebra. Cada plantilla consta de diferentes niveles y no se requirió del uso de rayos X trans­operatorios. RESULTADOS: Bajo monitoreo electrofisiológico transquirúrgico no se reportó ninguna «alerta roja¼; la evaluación postoperatoria por tomografía de la colocación de los tornillos mostró una desviación estándar de 1.9 y 2.2 mm tanto a la derecha y a la izquierda, respectivamente, de acuerdo con lo planeado. DISCUSIÓN: La técnica es simple y segura, no requiere de mucho despliegue tecnológico, se sugiere su uso para los cirujanos de columna con poca experiencia y para deformidades severas; consideramos que puede desarrollarse en cualquier hospital donde se realice cirugía de columna.

Demographic and clinical characteristics of patients with spinal cord injury: a single hospital-based study.

STUDY DESIGN: Retrospective study. OBJECTIVES: To evaluate the demographic and clinical characteristics of patients diagnosed with spinal cord injury (SCI) admitted to a single center. SETTING: Single center study, México. METHODS: This study reviewed 433 patients with SCI. Data were extracted from medical records and retrospectively reviewed. RESULTS: A total of 433 patients with a diagnosis of SCI were included in the analysis. Of these, 346 (79.9%) had traumatic SCI (TSCI) and 87 (20.1%) had non-traumatic SCI (NTSCI). The principal causes of traumatic TSCI were motor vehicle accidents in 150 patients (43.4%), falls in 107 patients (30.9%) and a result of firearms in 58 patients (16.8%). Tumoral cord compression was the main cause of NTSCI in 50 patients (57.4%), followed by degenerative disease-causing myelopathy in 17 patients (19.5%). The proportion of patients affected with NTSCI was significantly lower, 29.9 vs 79.1% (P=0.0001), the age of patients was higher 53.9 vs 37.8 (P<0.002) and SCI was less severe, AIS D 41.33 vs 9.5% (P=0.0001) compared with the TSCI group. CONCLUSIONS: The demographic profiles of patients with TSCI and NTSCI differ in terms of proportion of total SCIs, patient age, male:female ratio and incomplete vs complete injury. The most common etiology of TSCI was motor vehicle accidents (43.4%), and neurological lesions were complete in 62.7% of patients. The most common etiology of NTSCI was tumoral spinal lesions (57.4%), and lesions were incomplete in 75.8% of patients.