Short-term and long-term results of odontoid screw fixation in patients with Type II and rostral Type III dens fractures.

OBJECTIVES: To evaluate both the short-term and long-term outcomes of odontoid screw fixation (OSF), identifying potential risk factors for implant-related complications in patients with odontoid fractures. METHODS: This is a retrospective observational cohort study. Inclusion criteria were as follows: 1) Type II fractures and rostral Type III fractures, according to the Anderson and D'Alonzo classification; 2) patients older than 15 years. Exclusion criteria were: 1) other Type III injuries; 2) osteoporosis confirmed by densitometry or a CT bone density score below 100 Hounsfield units; 3) odontoid fractures related to tumors or aneurysmal bone cysts. RESULTS: In total, 56 patients were considered for the analysis of short-term results, and 26 patients were evaluated for long-term outcomes. No significant differences were observed in the preoperative imaging data and intraoperative features of OSF between patients with Type II and rostral Type III fractures. The mean operative duration was 63.9 ± 20.9 min, and the mean intraoperative blood loss was 22.1 ± 22.9 ml. Screw cut-out was identified in four patients with rostral Type III fractures (p = 0.04). The rate of screw cut-out was found to correlate with the degree of dens fragment displacement. The bone fusion rate was 95.7%. CT scans identified stable pseudarthrosis in two cases. We observed C2-C3 ankylosis in all cases following partial disc resection. One third of patients with screws placed through the anterior lip of C2 showed no C2-C3 ankylosis. A strong trend towards lateral joint ankylosis formation in patients with a median lateral mass dislocation of 11.9 mm was observed. Most SF-36 scores either matched or exceeded the corresponding normal median values in the published reference database. CONCLUSIONS: OSF is a reliable treatment method of Type II and rostral Type III odontoid fractures with fragment displacement of 4 mm or less. The minimally invasive OSF through the anterior-inferior lip of C2, using monocortical screw placement and cannulated instruments, without rigid intraoperative head immobilization, is sufficient to achieve favorable clinical and fusion results. This technique reduces the risk of ankylosis in the C2-C3 segment. OSF restore the quality of life for patients with odontoid fractures to levels comparable to those of the general population norm.

Pediatric atlas anatomy and its implications for fracture treatment: an anatomical and radiological study.

INTRODUCTION AND OBJECTIVES: The objective of the study was: (1) to describe changes in the shape of the atlas during growth, including gender and side differences; (2) to assess the dimension essential for identification of the optimal entry point; (3) to determine the age limit for a safe insertion of 3.5-mm screws into the lateral masses according to our own limiting parameters. MATERIALS AND METHODS: Dimensions of the atlas were measured on 200 CT scans of the craniocervical junction in individuals aged 0-18 years and on 34 anatomical specimens of the first cervical vertebra (aged 2.5-18 years). Both series were divided according to the gender and age. The values measured on CT scans were used for statistical comparison of data in boys and girls and comparison of the right and left sides. RESULTS: The atlas reaches its maximum growth rate between 0 and 2 years of age, then the growth decelerates and continues until the age of 18 years. The proportion of dimensions of C1 vertebral foramens changes with age. The youngest children show a relatively greater distance from the left to the right medial pedicle; around the age of 5 the values get even and subsequently the distance from the inner wall of anterior to posterior arch gets relatively greater. The transverse foramen has a slightly oval shape throughout the period of growth. Statistically significant differences between boys and girls were observed primarily between 12 and 18 years of age. CONCLUSION: The study has proved adequate size of lateral masses for insertion of 3.5-mm screws in all patients from the age of 5 years. In younger children, the patient´s anatomy should be respected and the surgical technique tailored accordingly.

[Translated article] Insertion of S1 iliosacral screws in the computed tomography room: An alternative to improve safety in the percutaneous management of posterior pelvic ring injuries.

INTRODUCTION: The main complication of percutaneous iliosacral screw fixation is implant malposition, which can lead to vascular and nerve damage. The anatomical variability of the sacrum can make screw insertion difficult under fluoroscopic guidance. Among the methods described to improve the accuracy of this technique, stands out the use of computed tomography (CT). The aim of this study is to compare the results of iliosacral screw insertion with fluoroscopy or CT navigation. METHODOLOGY: Retrospective cohort study of 66 iliosacral screws in 56 patients during 11 years. The screws were inserted with fluoroscopy in the operating room or with CT in the radiodiagnosis area. We collected data on patient characteristics, lesions, treatment, and clinical and radiological results. RESULTS: Forty-seven screws were inserted with fluoroscopy and 19 with CT. A percentage of 18.2 of screws perforated the S1 osseous corridor. All of them were inserted with fluoroscopy guidance (0 vs. 34%; p<0.01). Those operated with CT accumulated more sacral dysmorphism criteria than those operated with fluoroscopy (2.2 vs. 1.6; p=0.02). The S1 corridor on the axial CT view was narrower in those in whom perforation had occurred (18.8 vs. 21.0mm; p=0.02). Two cases with perforation developed S1 radiculalgia. Two endopelvic screws had to be removed. CONCLUSION: We advise the use of CT guidance for iliosacral screw insertion in patients with sacral dysmorphism or narrow S1 corridors in facilities where other navigation methods are not available.

Insertion of S1 iliosacral screws in the computed tomography room: An alternative to improve safety in the percutaneous management of posterior pelvic ring injuries. / Inserción de tornillos iliosacros S1 en la sala de tomografía computarizada. Una alternativa para mejorar la seguridad en el tratamiento percutáneo de las lesiones posteriores del anillo pélvico.

INTRODUCTION: The main complication of percutaneous iliosacral screw fixation is implant malposition, which can lead to vascular and nerve damage. The anatomical variability of the sacrum can make screw insertion difficult under fluoroscopic guidance. Among the methods described to improve the accuracy of this technique, stands out the use of computed tomography (CT). The aim of this study is to compare the results of iliosacral screw insertion with fluoroscopy or CT navigation. METHODOLOGY: Retrospective cohort study of 66 iliosacral screws in 56 patients during 11 years. The screws were inserted with fluoroscopy in the operating room or with CT in the radiodiagnosis area. We collected data on patient characteristics, lesions, treatment, and clinical and radiological results. RESULTS: Forty-seven screws were inserted with fluoroscopy and 19 with CT. A percentage of 18.2 of screws perforated the S1 osseous corridor. All of them were inserted with fluoroscopy guidance (0 vs. 34%; p<0.01). Those operated with CT accumulated more sacral dysmorphism criteria than those operated with fluoroscopy (2.2 vs. 1.6; p=0.02). The S1 corridor on the axial CT view was narrower in those in whom perforation had occurred (18.8 vs. 21.0mm; p=0.02). Two cases with perforation developed S1 radiculalgia. Two endopelvic screws had to be removed. CONCLUSION: We advise the use of CT guidance for iliosacral screw insertion in patients with sacral dysmorphism or narrow S1 corridors in facilities where other navigation methods are not available.

[Clinical and radiographic factors associated with failure of the dynamic hip screw system]. / Factores clínicos y radiográficos asociados a la falla del sistema del tornillo dinámico de cadera.

Background: The most widely used fixation system for transtrochanteric fractures is the dynamic hip screw system, which has a failure prevalence of 10 to 17% and it is associated with the presence of clinical and radiographic factors. Objective: To evaluate the association of clinical and radiographic factors with the failure of the screw system in post-operative patients for transtrochanteric hip fracture. Material y methods: A case-control study was carried out. The inclusion criteria were: patients > 18 years, who underwent surgery due to transtrochanteric fracture, were treated with the hip screw system, and who attended the Trauma Service. The patient with failure of the hip screw system was selected as the case and the patient without failure of the system as control. The variables analyzed in these groups were: age, gender, body mass index and radiographic variables. Statistical analysis was performed with chi-squared and Mann-Whitney U. Results: 163 patients (median 73 years), 20 cases and 143 controls, were included. The radiographic factors with a significant association with hip screw system failure were the AO classification of fractures (p < 0.001), the tip apex distance (p = 0.03), the calcar-referenced tip apex (p = 0.02), the position of the screw (p < 0.001), and quality of reduction (p < 0.003). Clinical factors did not show a significant association. Conclusions: Radiographic factors are associated with failure in the hip screw system in patients in post-operative care due to transtrochanteric fracture.

Introducción: el sistema de fijación más usado para fracturas transtrocantéricas es el sistema del tornillo dinámico de cadera, el cual tiene una prevalencia de falla del 10 al 17% y se asocia a la presencia de factores clínicos y radiográficos. Objetivo: evaluar la asociación de los factores clínicos y radiográficos con la falla del sistema del tornillo en pacientes postoperados de fractura transtrocantérica de cadera. Material y métodos: se hizo un estudio de casos y controles. Los criterios de inclusión fueron: pacientes > 18 años, postoperados de fractura transtrocantérica, tratados con el sistema del tornillo de cadera, que acudieron a la consulta de Traumatología. Se seleccionó como caso al paciente con falla del sistema del tornillo de cadera y como control al paciente sin falla de este. Las variables analizadas en los grupos fueron la edad, el género, el índice de masa corporal y las variables radiográficas. El análisis estadístico se hizo con chi cuadrada y U de Mann-Whitney. Resultados: se incluyeron 163 pacientes (mediana de 73 años), 20 casos y 143 controles. Los factores radiográficos con asociación significativa con la falla del sistema del tornillo de cadera fueron la clasificación AO de la fractura (p < 0.001), la distancia punta-ápex (p = 0.03), punta ápex calcar (p = 0.02), la posición del tornillo (p < 0.001) y la calidad de la reducción (p < 0.003). Los factores clínicos no mostraron asociación significativa. Conclusiones: los factores radiográficos se asocian con la falla en el sistema del tornillo de cadera en pacientes postoperados de fractura transtrocantérica.

Comparación de tres técnicas de tornillo endomedular mínimamente invasivo para fracturas de falange proximal. Estudio biomecánico / Comparison of three different minimally invasive intramedullary screw for proximal phalanx fractures. A biomechanical study

Antecedentes y objetivo: Las fracturas de falange proximal (FP) son las fracturas más frecuentes de la mano. En los últimos años, se ha descrito el uso de tornillos endomedulares sin cabeza (TESC) para las fracturas inestables transversas u oblicuas de la FP. A pesar de que tanto la técnica anterógrada como retrógrada con TESC han mostrado buenos resultados, no se ha publicado ningún estudio comparativo de su uso en fracturas de FP. Nuestro objetivo es determinar la estabilidad que se obtiene con el uso de TESC retrógrados y anterógrados en un modelo en cadáver de fractura transversa proximal de FP, a dos niveles diferentes. Material y métodos: Realizamos un estudio biomecánico en 30 modelos de fractura de FP de cadáver fresco-congelado. La osteotomía se realizó a los 9 mm desde la articulación metacarpofalángica (MCF) en 15 especímenes, y a una distancia de 15 mm en los otros 15. A su vez, en cada grupo, cinco osteotomías se estabilizaron con un TESC anterógrado intraarticular, cinco mediante un TESC anterógrado transarticular y cinco con un TESC retrógrado. Resultados: La fijación con TESC anterógrado en osteotomías realizadas a los 9 mm (tanto con la técnica transarticular como intraarticular, 62,74 N y 70,86 N, respectivamente) fue más estable que la fijación con TESC retrógrado (32,72 N) (p 0,022). Por otra parte, la fijación con TESC retrógrado fue más estable en el modelo de fractura más distal (90,52 N retrógrado vs. 57,64 N transarticular vs. 42,92 N intraarticular (p = 0,20). Conclusiones: La fijación con TESC retrógrado ofrece más estabilidad en fracturas más distales, mientras que las técnicas anterógradas son más estables en fracturas proximales.(AU)

Background and objective: Phalangeal fractures are the most common hand fractures. In the last years, intramedullary compression screw (IMHCS) for instable transverse or short oblique proximal P1 fractures have been described. Although both anterograde (intraarticular or trans-articular) and retrograde IMHCS techniques have shown good results, no comparison between anterograde and retrograde screw in P1 fractures has been published. We sought to determine stability with retrograde IMHCS and anterograde IMHCS, both trans-articular and intra-articular technique, in a cadaveric transverse proximal P1 fracture model, at two different levels. Material and methods: We performed a biomechanical study in 30 fresh-frozen human cadaveric P1 fracture model. Fracture was performed at 9-mm from the metacarpo-phalangeal (MCP) joint in 15 specimens, whereas it was done at 15 mm in the other 15. In turn, in each group, five fractures were stabilized with an anterograde intra-articular IMHCS, five with anterograde trans-articular IMHCS and other five with retrograde IMHCS. Results: Anterograde IMHCS fixation in 9-mm P1 fractures (both trans- and intra-articular technique, 62.74 N and 70.86 N, respectively) was found to be more stable than retrograde IMHCS one (32.72 N) (p = 0.022). Otherwise, retrograde IMHCS fixation was found to be more stable in more distal P1 fractures (90.52 N retrograde vs. 57.64 N trans-articular vs. 42.92 N intra-articular; p = 0.20). Conclusions: Anterograde IMHCS fixation in proximal transverse P1 bone cut in a cadaveric model provides more stability than retrograde IMHCS, while retrograde screw provides more stability when the bone cut is located more distal.(AU)

[Translated article] Comparison of three different minimally invasive intramedullary screw for proximal phalanx fractures. A biomechanical study / Comparación de tres técnicas de tornillo endomedular mínimamente invasivo para fracturas de falange proximal. Estudio biomecánico

Background and objective: Phalangeal fractures are the most common hand fractures. In the last years, intramedullary compression screw (IMHCS) for instable transverse or short oblique proximal P1 fractures have been described. Although both anterograde (intraarticular or trans-articular) and retrograde IMHCS techniques have shown good results, no comparison between anterograde and retrograde screw in P1 fractures has been published. We sought to determine stability with retrograde IMHCS and anterograde IMHCS, both trans-articular and intra-articular technique, in a cadaveric transverse proximal P1 fracture model, at two different levels. Material and methods: We performed a biomechanical study in 30 fresh-frozen human cadaveric P1 fracture model. Fracture was performed at 9-mm from the metacarpo-phalangeal (MCP) joint in 15 specimens, whereas it was done at 15 mm in the other 15. In turn, in each group, five fractures were stabilized with an anterograde intra-articular IMHCS, five with anterograde trans-articular IMHCS and other five with retrograde IMHCS. Results: Anterograde IMHCS fixation in 9-mm P1 fractures (both trans- and intra-articular technique, 62.74 N and 70.86 N, respectively) was found to be more stable than retrograde IMHCS one (32.72 N) (p = 0.022). Otherwise, retrograde IMHCS fixation was found to be more stable in more distal P1 fractures (90.52 N retrograde vs. 57.64 N trans-articular vs. 42.92 N intra-articular; p = 0.20). Conclusions: Anterograde IMHCS fixation in proximal transverse P1 bone cut in a cadaveric model provides more stability than retrograde IMHCS, while retrograde screw provides more stability when the bone cut is located more distal.(AU)

Antecedentes y objetivo: Las fracturas de falange proximal (FP) son las fracturas más frecuentes de la mano. En los últimos años, se ha descrito el uso de tornillos endomedulares sin cabeza (TESC) para las fracturas inestables transversas u oblicuas de la FP. A pesar de que tanto la técnica anterógrada como retrógrada con TESC han mostrado buenos resultados, no se ha publicado ningún estudio comparativo de su uso en fracturas de FP. Nuestro objetivo es determinar la estabilidad que se obtiene con el uso de TESC retrógrados y anterógrados en un modelo en cadáver de fractura transversa proximal de FP, a dos niveles diferentes. Material y métodos: Realizamos un estudio biomecánico en 30 modelos de fractura de FP de cadáver fresco-congelado. La osteotomía se realizó a los 9 mm desde la articulación metacarpofalángica (MCF) en 15 especímenes, y a una distancia de 15 mm en los otros 15. A su vez, en cada grupo, cinco osteotomías se estabilizaron con un TESC anterógrado intraarticular, cinco mediante un TESC anterógrado transarticular y cinco con un TESC retrógrado. Resultados: La fijación con TESC anterógrado en osteotomías realizadas a los 9 mm (tanto con la técnica transarticular como intraarticular, 62,74 N y 70,86 N, respectivamente) fue más estable que la fijación con TESC retrógrado (32,72 N) (p 0,022). Por otra parte, la fijación con TESC retrógrado fue más estable en el modelo de fractura más distal (90,52 N retrógrado vs. 57,64 N transarticular vs. 42,92 N intraarticular (p = 0,20). Conclusiones: La fijación con TESC retrógrado ofrece más estabilidad en fracturas más distales, mientras que las técnicas anterógradas son más estables en fracturas proximales.(AU)

Comparison of three different minimally invasive intramedullary screw for proximal phalanx fractures. A biomechanical study. / Comparación de tres técnicas de tornillo endomedular mínimamente invasivo para fracturas de falange proximal. Estudio biomecánico.

BACKGROUND AND OBJECTIVE: Phalangeal fractures are the most common hand fractures. In the last years, intramedullary compression screw (IMHCS) for instable transverse or short oblique proximal P1 fractures have been described. Although both anterograde (intraarticular or trans-articular) and retrograde IMHCS techniques have shown good results, no comparison between anterograde and retrograde screw in P1 fractures has been published. We sought to determine stability with retrograde IMHCS and anterograde IMHCS, both trans-articular and intra-articular technique, in a cadaveric transverse proximal P1 fracture model, at two different levels. MATERIAL AND METHODS: We performed a biomechanical study in 30 fresh-frozen human cadaveric P1 fracture model. Fracture was performed at 9-mm from the metacarpo-phalangeal (MCP) joint in 15 specimens, whereas it was done at 15 mm in the other 15. In turn, in each group, five fractures were stabilized with an anterograde intra-articular IMHCS, five with anterograde trans-articular IMHCS and other five with retrograde IMHCS. RESULTS: Anterograde IMHCS fixation in 9-mm P1 fractures (both trans- and intra-articular technique, 62.74 N and 70.86 N, respectively) was found to be more stable than retrograde IMHCS one (32.72 N) (p = 0.022). Otherwise, retrograde IMHCS fixation was found to be more stable in more distal P1 fractures (90.52 N retrograde vs. 57.64 N trans-articular vs. 42.92 N intra-articular; p = 0.20). CONCLUSIONS: Anterograde IMHCS fixation in proximal transverse P1 bone cut in a cadaveric model provides more stability than retrograde IMHCS, while retrograde screw provides more stability when the bone cut is located more distal.

[Translated article] Comparison of three different minimally invasive intramedullary screw for proximal phalanx fractures. A biomechanical study.

BACKGROUND AND OBJECTIVE: Phalangeal fractures are the most common hand fractures. In the last years, intramedullary compression screw (IMHCS) for instable transverse or short oblique proximal P1 fractures have been described. Although both anterograde (intraarticular or trans-articular) and retrograde IMHCS techniques have shown good results, no comparison between anterograde and retrograde screw in P1 fractures has been published. We sought to determine stability with retrograde IMHCS and anterograde IMHCS, both trans-articular and intra-articular technique, in a cadaveric transverse proximal P1 fracture model, at two different levels. MATERIAL AND METHODS: We performed a biomechanical study in 30 fresh-frozen human cadaveric P1 fracture model. Fracture was performed at 9-mm from the metacarpo-phalangeal (MCP) joint in 15 specimens, whereas it was done at 15mm in the other 15. In turn, in each group, five fractures were stabilised with an anterograde intra-articular IMHCS, five with anterograde trans-articular IMHCS and other five with retrograde IMHCS. RESULTS: Anterograde IMHCS fixation in 9-mm P1 fractures (both trans- and intra-articular technique, 62.74N and 70.86N, respectively) was found to be more stable than retrograde IMHCS one (32.72N) (p=0.022). Otherwise, retrograde IMHCS fixation was found to be more stable in more distal P1 fractures (90.52N retrograde vs. 57.64N trans-articular vs. 42.92N intra-articular; p=0.20). CONCLUSIONS: Anterograde IMHCS fixation in proximal transverse P1 bone cut in a cadaveric model provides more stability than retrograde IMHCS, while retrograde screw provides more stability when the bone cut is located more distal.

Ensayo clínico comparando el uso de tornillos y del sistema TighRope® Knotless en el tratamiento de las lesiones agudas de la sindesmosis / A randomized clinical trial comparing screws and the TighRope® Knotless system in the treatment of acute injuries of syndesmosis

Antecedentes y objetivo: Clásicamente el tratamiento de las lesiones agudas de la sindesmosis se ha realizado mediante tornillos. Hace unos años aparecieron implantes más flexibles que han evolucionado hasta el moderno TighRope® Knotless. El objetivo del presente estudio es comparar los resultados de ambos implantes. Material y métodos: Desde abril de 2019 hasta septiembre de 2020 reclutamos 68 pacientes diagnosticados de lesión aguda de la sindesmosis que fueron aleatorizados para tratamiento quirúrgico con tornillo o con TighRope® Knotless. Realizamos control posquirúrgico con tomografía axial computarizada, y a los 3, 6 y 12 meses se recogieron datos del rango articular, valores de escalas funcionales y se realizaron estudios de radiología simple. Resultados: Los pacientes tratados con tornillos no presentaban diferencias estadísticamente significativas en la escala AOFAS frente al grupo tratado con TighRope® Knotless a los 3 meses (83,1 vs. 81,80; p=1,03), ni a los 6 meses (88,27 vs. 88; p=0,26) ni a los 12 meses (93,03 vs. 92,10; p=0,93). Igualmente recogimos resultados similares en la escala de Olerud-Molander a los 3 meses (65 vs. 61,50; p=3,5), 6 meses (82,33 vs. 80,67; p=1,67) y 12 meses (92,67 vs. 90; p=2,67). Tampoco hubo diferencias en la tasa de malreducción posquirúrgica (ningún caso en ambos grupos), pérdida de reducción (3 en el grupo tratado con tornillo frente a 4 del grupo del TighRope® Knotless, p=0,54) o complicaciones (p=1). Conclusiones: El tratamiento de las lesiones agudas de la sindesmosis con tornillos o con TighRope® Knotless es similar tanto en resultados clínicos como radiológicos.(AU)

Background and aim: Classically acute syndesmosis injuries have been treated using screws. A few years ago more flexible implants appeared evolving to current TighRope® Knotless. The primary aim of this study is to compare clinical and radiographic outcome of both implants. Material and methods: From April 2019 to September 2020 68 patients diagnosed with acute syndesmosis injury were randomized to use screws or TighRope® Knotless. Syndesmosis reduction was assessed using bilateral CT potsoperatively. Outcomes were clinically and radiologically assessed at three, six, and twelve months after surgery. Results: No significant differences were identified in the AOFAS Scale between groups at three months (83.1 vs. 81.80; P=1.03), nor at six (88.27 vs. 88; P=.26) or at twelve (93.03 vs. 92.10; P=,93). There were also no differences in Olerud-Molander scale at three (65 vs. 61.50; P=3.5), six (82.33 vs. 80.67; P=1.67) and twelve months (92.67 vs. 90; P=2.67). Likewise, there were no differences in rate of postoperative malreduction (no cases in both groups), loss of reduction (three cases in screw group vs. four in TighRope® Knotless group, P=.54) or complications (P=1). Conclusions: Treatment of acute syndesmosis injuries with screws or the TighRope® Knotless implant is similar in both clinical and radiological results.(AU)

[Translated article] A randomised clinical trial comparing screws and the TighRope® Knotless system in the treatment of acute injuries of syndesmosis / Ensayo clínico comparando el uso de tornillos y del sistema TighRope® Knotless en el tratamiento de las lesiones agudas de la sindesmosis

Antecedentes y objetivo: Clásicamente el tratamiento de las lesiones agudas de la sindesmosis se ha realizado mediante tornillos. Hace unos años aparecieron implantes más flexibles que han evolucionado hasta el moderno TighRope® Knotless. El objetivo del presente estudio es comparar los resultados de ambos implantes. Material y métodos: Desde abril de 2019 hasta septiembre de 2020 reclutamos 68 pacientes diagnosticados de lesión aguda de la sindesmosis que fueron aleatorizados para tratamiento quirúrgico con tornillo o con TighRope® Knotless. Realizamos control posquirúrgico con tomografía axial computarizada, y a los 3, 6 y 12 meses se recogieron datos del rango articular, valores de escalas funcionales y se realizaron estudios de radiología simple. Resultados: Los pacientes tratados con tornillos no presentaban diferencias estadísticamente significativas en la escala AOFAS frente al grupo tratado con TighRope® Knotless a los 3 meses (83,1 vs. 81,80; p=1,03), ni a los 6 meses (88,27 vs. 88; p=0,26) ni a los 12 meses (93,03 vs. 92,10; p=0,93). Igualmente recogimos resultados similares en la escala de Olerud-Molander a los 3 meses (65 vs. 61,50; p=3,5), 6 meses (82,33 vs. 80,67; p=1,67) y 12 meses (92,67 vs. 90; p=2,67). Tampoco hubo diferencias en la tasa de malreducción posquirúrgica (ningún caso en ambos grupos), pérdida de reducción (3 en el grupo tratado con tornillo frente a 4 del grupo del TighRope® Knotless, p=0,54) o complicaciones (p=1). Conclusiones: El tratamiento de las lesiones agudas de la sindesmosis con tornillos o con TighRope® Knotless es similar tanto en resultados clínicos como radiológicos.(AU)

Background and aim: Classically acute syndesmosis injuries have been treated using screws. A few years ago more flexible implants appeared evolving to current TighRope® Knotless. The primary aim of this study is to compare clinical and radiographic outcome of both implants. Material and methods: From April 2019 to September 2020 68 patients diagnosed with acute syndesmosis injury were randomized to use screws or TighRope® Knotless. Syndesmosis reduction was assessed using bilateral CT potsoperatively. Outcomes were clinically and radiologically assessed at three, six, and twelve months after surgery. Results: No significant differences were identified in the AOFAS Scale between groups at three months (83.1 vs. 81.80; P=1.03), nor at six (88.27 vs. 88; P=.26) or at twelve (93.03 vs. 92.10; P=,93). There were also no differences in Olerud-Molander scale at three (65 vs. 61.50; P=3.5), six (82.33 vs. 80.67; P=1.67) and twelve months (92.67 vs. 90; P=2.67). Likewise, there were no differences in rate of postoperative malreduction (no cases in both groups), loss of reduction (three cases in screw group vs. four in TighRope® Knotless group, P=.54) or complications (P=1). Conclusions: Treatment of acute syndesmosis injuries with screws or the TighRope® Knotless implant is similar in both clinical and radiological results.(AU)

[Translated article] A randomised clinical trial comparing screws and the TighRope® Knotless system in the treatment of acute injuries of syndesmosis.

BACKGROUND AND AIM: Classically acute syndesmosis injuries have been treated using screws. A few years ago more flexible implants appeared evolving to current TighRope® Knotless. The primary aim of this study is to compare clinical and radiographic outcome of both implants. MATERIAL AND METHODS: From April 2019 to September 2020 68 patients diagnosed with acute syndesmosis injury were randomised to use screws or TighRope® Knotless. Syndesmosis reduction was assessed using bilateral CT potsoperatively. Outcomes were clinically and radiologically assessed at three, six, and twelve months after surgery. RESULTS: No significant differences were identified in the AOFAS Scale between groups at three months (83.1 vs. 81.80; P=1.03), nor at six (88.27 vs. 88; P=.26) or at twelve (93.03 vs. 92.10; P=.93). There were also no differences in Olerud-Molander scale at three (65 vs. 61.50; P=3.5), six (82.33 vs. 80.67; P=1.67) and twelve months (92.67 vs. 90; P=2.67). Likewise, there were no differences in rate of postoperative malreduction (no cases in both groups), loss of reduction (three cases in screw group vs. four in TighRope® Knotless group, P=.54) or complications (P=1). CONCLUSIONS: Treatment of acute syndesmosis injuries with screws or the TighRope® Knotless implant is similar in both clinical and radiological results.

Biomecánica de la interfaz hueso-tornillo en instrumentación transpedicular de columna / Biomechanics of the bone-screw interface in transpedicular spinal instrumentation

Resumen: El aflojamiento de los implantes, la falla catastrófica de la interfaz hueso-tornillo, la migración de material y la pérdida de estabilidad de los componentes del ensamble de la fijación constituyen una seria complicación en la cirugía de columna de adultos. La contribución de la biomecánica se basa en la medición experimental y la simulación de las fijaciones transpediculares de columna. La trayectoria de inserción cortical mostró un incremento en la resistencia de la interfase tornillo-hueso respecto a la inserción pedicular tanto para fuerzas de tracción axiales al tornillo como en distribución de esfuerzos en la vértebra. Los tornillos de doble rosca tuvieron una resistencia similar a los pediculares estándar. Los tornillos de rosca parcial de cuatro filetes mostraron mejor resistencia a la fatiga en cuanto a mayor carga de rotura y número de ciclos para la falla. Los tornillos aumentados, ya sea con cemento o hidroxiapatita mejoraron también la resistencia a la fatiga en vértebras osteoporóticas. Las simulaciones de segmentos rígidos confirmaron la presencia de esfuerzos superiores en los discos intervertebrales que provocan el daño de los segmentos adyacentes. La parte posterior de las vértebras puede estar sometida a mayores esfuerzos, fundamentalmente en la superficie de la interfaz hueso-tornillo, por lo que son más susceptibles a la falla en esta región.

Abstract: Implant loosening, catastrophic failure of the bone-screw interface, material migration, and loss of stability of the fixation component assembly constitute a serious complication in adult spinal surgery. The contribution of biomechanics is based on experimental measurement and simulation of transpedicular spinal fixations. The cortical insertion trajectory showed an increase in the resistance of the screw-bone interface with respect to the pedicle insertion trajectory, both for axial traction forces to the screw and for stress distribution in the vertebra. The double-threaded screws and standard pedicle screws had similar strength. Partially threaded screws with four-thread showed better resistance to fatigue in terms of a higher failure load and number of cycles to fail. Cement or hydroxyapatite augmented screws with also showed a better fatigue resistance in osteoporotic vertebrae. Rigid segment simulations confirmed the presence of higher stresses on the intervertebral discs causing damage to adjacent segments. The posterior body of the vertebra may be subjected to high stresses, in the bone-screw interface, being this bone region more susceptible to failure.

The role of cross-link augmentation on fusion rate and patient satisfaction among patients with traumatic thoracolumbar spinal fracture: A randomized clinical trial / El papel del aumento de los enlaces cruzados en la tasa de fusión y la satisfacción del paciente entre los pacientes con fractura traumática de la columna vertebral toracolumbar: un ensayo clínico aleatorizado

Introduction and objectivesMost of the studies evaluating the effect of cross links on spinal stability are performed in vitro on porcine or human spine segments and there is limited data regarding clinical benefits of cross link augmentation in traumatic injuries. In this study we aimed to evaluate the effects of cross-links insertion between rods on the fusion rates and post-surgical patients’ satisfaction among patients with traumatic thoracolumbar fractures who underwent posterior spinal fixation with pedicle screws.Materials and methodsThis study was conducted as a randomized clinical trial on 60 patients suffering from traumatic thoracolumbar vertebrae fractures. Patients were randomized into three groups: A (without any cross-link), B (One cross-link insertion) and C (two cross-links insertion). Six months after surgery outcomes were evaluated: fusion rates (plain X-ray and CT scan), Back pain (Visual Analog Scale) and patient satisfaction (fair, good, excellent).ResultsIn group A 13 (65%) patients had structured bone fusion, but in 7 (35%) patients bone fusion was not observed. In both groups B and C, 19 patients (95%) had bone fusion, but only in 1 patient (5%) fusion failed (p=0.009). In group A, fair satisfaction has the highest rate (8 patients (40%)) compared to the other groups. The highest reported severity of back pain was observed in group A while the lowest reported intensity of back pain was related to group B (p=0.001).ConclusionsAdding cross link to posterior spinal fixations of patients with traumatic thoracolumbar fractures can be associated with better final fusion results and patients’ satisfaction. However it is necessary to design studies with greater sample sizes to confirm this theory (AU)

Introducción y objetivosLa mayor parte de los estudios que evaluaron el efecto de los enlaces cruzados en la estabilidad de la columna vertebral se realizaron in vitro en segmentos de la columna vertebral porcina o humana, existen pocos datos sobre los beneficios del aumento de los enlaces cruzados en las lesiones traumáticas. El objetivo de este estudio era evaluar los efectos de la inserción de enlaces cruzados entre las varillas en las tasas de fusión y la satisfacción posoperatoria de los pacientes con fracturas traumáticas toracolumbares que se habían sometido a fijación vertebral posterior con tornillos pediculares.Materiales y métodosEste estudio se realizó como un ensayo clínico aleatorizado de 60 pacientes que presentaban fracturas vertebrales toracolumbares traumáticas. Los pacientes se aleatorizaron en 3 grupos: A (sin ningún enlace cruzado), B (inserción de un enlace cruzado) y C (inserción de 2 enlaces cruzados). Se evaluaron los resultados 6 meses después de la intervención quirúrgica: tasas de fusión (radiografía simple y TC), dolor de espalda (escala analógica visual) y satisfacción del paciente (correcta, buena, excelente).ResultadosEn el grupo A, 13 (65%) pacientes presentaban fusión ósea estructural, pero en 7 (35%) pacientes no se observó fusión ósea. En los grupos B y C, 19 pacientes (95%) presentaban fusión ósea y solo en un paciente (5%) se observó el fracaso de la fusión (p=0,009). En el grupo A, la satisfacción más alta era correcta (8 pacientes [40%]) en comparación con los otros grupos. La mayor intensidad del dolor de espalda notificada se observó en el grupo A, mientras que la menor intensidad del dolor de espalda notificada se observó en el grupo B...(AU)

The role of cross-link augmentation on fusion rate and patient satisfaction among patients with traumatic thoracolumbar spinal fracture: A randomized clinical trial.

INTRODUCTION AND OBJECTIVES: Most of the studies evaluating the effect of cross links on spinal stability are performed in vitro on porcine or human spine segments and there is limited data regarding clinical benefits of cross link augmentation in traumatic injuries. In this study we aimed to evaluate the effects of cross-links insertion between rods on the fusion rates and post-surgical patients' satisfaction among patients with traumatic thoracolumbar fractures who underwent posterior spinal fixation with pedicle screws. MATERIALS AND METHODS: This study was conducted as a randomized clinical trial on 60 patients suffering from traumatic thoracolumbar vertebrae fractures. Patients were randomized into three groups: A (without any cross-link), B (One cross-link insertion) and C (two cross-links insertion). Six months after surgery outcomes were evaluated: fusion rates (plain X-ray and CT scan), Back pain (Visual Analog Scale) and patient satisfaction (fair, good, excellent). RESULTS: In group A 13 (65%) patients had structured bone fusion, but in 7 (35%) patients bone fusion was not observed. In both groups B and C, 19 patients (95%) had bone fusion, but only in 1 patient (5%) fusion failed (p=0.009). In group A, fair satisfaction has the highest rate (8 patients (40%)) compared to the other groups. The highest reported severity of back pain was observed in group A while the lowest reported intensity of back pain was related to group B (p=0.001). CONCLUSIONS: Adding cross link to posterior spinal fixations of patients with traumatic thoracolumbar fractures can be associated with better final fusion results and patients' satisfaction. However it is necessary to design studies with greater sample sizes to confirm this theory. TRIAL REGISTRATION NUMBER: IRCT20120527009878N3.

Triggered electromyography (tEMG) in the lumbar spine It́s reliable? Correlation of tEMG with postoperative CT images in lumbar instrumentation. / Electromiografía evocada (tEMG) en la columna lumbar. ¿Es confiable? Correlación de tEMG con imágenes de TC posoperatorias en la instrumentación lumbar.

INTRODUCTION: Instrumentation with pedicle screws (PS) can compromise the adjacent neural structures. Triggered electromyography (tEMG) is a modality of intraoperative neuromonitoring, used to assist in the placement of these. The objective of the present study is to evaluate the reliability of this tool. METHOD: Retrospective review of patients underwent posterior lumbar fusions from January 2017 to December 2019, correlating postoperative CT images (postop CT) with tEMG results for each PS with a threshold of 10mA, establishing sensitivity and specificity of this tool. Diagnostic test and receiver operating characteristic curve were performed to evaluate the area under the curve. RESULT: A total of 275 PS were evaluated between L1 to S1; 5 PS showed concordance for an inadequate trajectory, while 10PS, with tEMG <10mA, were correctly positioned. The postoperative CT identified 17 pedicle gaps not noticed by the tEMG. Sensitivity and specificity were 23% (95% CI: 8-45) and 96% (95% CI: 93-98), respectively, with a PPV of 33.3% and a NPV of 93.6%. The area under the curve was 0.74 (95% CI: 0.62-0.86) with a cut-off point of 24mA, showing a sensitivity of 77% (95% CI: 0.55-0.92) and specificity of 69% (95% CI: 0.63-0.75). CONCLUSION: Given its low sensitivity, we do not recommend tEMG as the sole test in the verification of PS. We recommend using a cut-off point ≤8mA as it demonstrated the highest levels of sensitivity and specificity. We do not recommend using high thresholds to increase sensitivity.

La fijación con tornillo de interferencia tibial cuadrante específico permite un constante desplazamiento de los injertos de tejido dentro de tuneles tibiales mal poscionados: análisis cuantitativo de ligamento cruzado anterior en porcinos / Quadrant specific tibial interference screw fixation allows constant displacement of soft tissue grafts inside misplaced tibial tunnels: a porcine anterior cruciate ligament quantitative assessment study

INTRODUCCIÓN El error técnico más común durante la reconstrucción del ligamento cruzado anterior (LCA) es la ubicación incorrecta del túnel. Es incierto si un túnel tibial mal ubicado puede corregirse en el intraoperatorio. OBJETIVO Medir el desplazamiento del injerto de tejido blando con tornillos de interferencia tibial.MATERIALES Y MÉTODOS Estudio experimental ex vivo en 28 rodillas porcinas. Se cosechó el tendón flexor de la extremidad posterior, que fue duplicado y dimensionado para que pasara a través de un túnel tibial mal posicionado. Las muestras se dividieron en 4 grupos según el cuadrante de entrada (anterior [A], posterior [P], medial [M], o lateral [L]) de un tornillo de interferencia tibial de 9 mm con relación al injerto. Se ubicó una regla milimétrica en la meseta tibial, la cual fue fotografiada con una cámara EOS T6 (Canon Inc., Ota, Tokio, Japón), y la imagen fue digitalizada, y puesta en escala a tamaño. La distancia y dirección de los desplazamientos del injerto se midieron con Adobe Photoshop CC 2019 (San José, CA, EEUU). Se analizaron las diferencias medias entre los grupos por análisis de la varianza (analysis of variance, ANOVA, en inglés) unidireccional. El análisis estadístico se realizó con el programa Statistical Package for the Social Sciences (IBM SPSS Statistics for Windows, IBM Corp., Armonk, NY, EEUU), versión 25.0 (p ≤ 0,05)).RESULTADOS La distancias medias de los desplazamientos del injerto fueron similares en todos los grupos: A ­ 4,4 mm; P ­ 4,6 mm; M ­ 4,5 mm; y L ­ 4,3 mm, sin diferencias estadísticamente significativas (p = 0,894). Las direcciones medias de los desplazamientos del injerto también fueron similares entre los 4 grupos: A ­ 176° (desviación estándar [DE]: ± 15,4°); P ­ 165° (DE: ± 16,6°); M ­ 166° (DE: ± 12,1°); y L ­ 169° (DE: ± 10,6°). No se encontraron diferencias estadísticamente significativas (p = 0.42).CONCLUSIONES Independientemente del cuadrante de entrada, se observó un desplazamiento constante del injerto hacia el lado opuesto cuando el tornillo tibial alcanzaba la superficie articular. Relevancia clínica: el tornillo tibial mal posicionado puede corregirse en el intraoperatorio con fijación proximal en cuadrante específico, y debe alcanzar la superficie articular para generar un desplazamiento efectivo del injerto. Sin embargo, no podemos predecir la magnitud de error en todos los túneles mal brocados, que debe ser evaluada caso a caso.

BACKGROUND The most common technical error during anterior cruciate ligament (ACL) reconstruction is incorrect tunnel placement. It remains unclear if a misplaced tibial tunnel may be corrected intraoperatively. AIM To measure the displacement of soft-tissue grafts with tibial interference screws. MATERIALS AND METHODS Ex-vivo experimental study in 28 porcine knees. The flexor tendon of the posterior limb was harvested, doubled and sized to fit through a 9-mm misplaced tibial tunnel. The specimens were divided into 4 groups according to the quadrant of entry (anterior [A], posterior [P], medial [M], or lateral [L]) of a 9-mm tibial interference screw in relation to the graft. A millimetric ruler was placed at the tibial plateau, which was photographed with a an EOS T6 (Canon Inc., Ota, Tokio, Japan) camera, and the image was digitalized and scaled to size. The length and direction of the graft displacements were measured with Adobe Photoshop CC 2019 (San José, CA, US). The mean differences among the groups were analyzed through one-way analysis of variance (ANOVA). The statistical analysis was performed using the Statistical Package for the Social Sciences (IBM SPSS Statistics for Windows, IBM Corp., Armonk, NY, US) software, version 25.0 (p 0.05) RESULTS The mean lengths of the graft displacements were similar among the groups: A ­ 4.4 mm; P ­4.6 mm; M ­ 4.5 mm; and L ­ 4.3 mm, without statistically significant differences (p » 0.894). The mean directions of the graft displacements were also similar among the groups: A ­ 176° (standard deviation [SD]: 15.4°); P ­ 165° (SD: 16.6°); M ­ 166° (SD: 12.1°); and L ­ 169° (SD: 10.6°). No statistically significant differences were found (p » 0.42). CONCLUSIONS Regardless of the entry quadrant, constant graft displacement to the opposite side was observed when the tibial screw reached the articular surface. Clinical relevance: a misplaced tibial tunnel may be corrected intraoperatively with a quadrantspecific screw, which must reach the articular surface to produce an effective graft displacement. Nevertheless, we cannot predict the magnitude of this error in every poorly-drilled tibial tunnel; it should be assessed case by case.

A randomized clinical trial comparing screws and the TighRope® Knotless system in the treatment of acute injuries of syndesmosis. / Ensayo clínico comparando el uso de tornillos y del sistema TighRope® Knotless en el tratamiento de las lesiones agudas de la sindesmosis.

BACKGROUND AND AIM: Classically acute syndesmosis injuries have been treated using screws. A few years ago more flexible implants appeared evolving to current TighRope® Knotless. The primary aim of this study is to compare clinical and radiographic outcome of both implants. MATERIAL AND METHODS: From April 2019 to September 2020 68 patients diagnosed with acute syndesmosis injury were randomized to use screws or TighRope® Knotless. Syndesmosis reduction was assessed using bilateral CT potsoperatively. Outcomes were clinically and radiologically assessed at three, six, and twelve months after surgery. RESULTS: No significant differences were identified in the AOFAS Scale between groups at three months (83.1 vs. 81.80; P=1.03), nor at six (88.27 vs. 88; P=.26) or at twelve (93.03 vs. 92.10; P=,93). There were also no differences in Olerud-Molander scale at three (65 vs. 61.50; P=3.5), six (82.33 vs. 80.67; P=1.67) and twelve months (92.67 vs. 90; P=2.67). Likewise, there were no differences in rate of postoperative malreduction (no cases in both groups), loss of reduction (three cases in screw group vs. four in TighRope® Knotless group, P=.54) or complications (P=1). CONCLUSIONS: Treatment of acute syndesmosis injuries with screws or the TighRope® Knotless implant is similar in both clinical and radiological results.

Electromiografía evocada (tEMG) en la columna lumbar. ¿Es confiable? Correlación de tEMG con imágenes de TC posoperatorias en la instrumentación lumbar / Triggered electromyography (tEMG) in the lumbar spine Its reliable? Correlation of tEMG with postoperative CT images in lumbar instrumentation

Introducción: La instrumentación con tornillos pediculares (TP) puede comprometer las estructuras neurales adyacentes. La electromiografía evocada (tEMG) es una modalidad del neuromonitoreo intraoperatorio utilizada para asistir la colocación de estos. El objetivo del presente estudio es evaluar la confiabilidad de esta herramienta. Método: Revisión retrospectiva de pacientes intervenidos de artrodesis lumbar posterolateral instrumentada desde enero del 2017 hasta diciembre del 2019. Se correlacionaron las imágenes de TC postoperatorias (TC-postop) con los resultados de la tEMG para cada TP con un umbral de 10mA, y se establecieron la sensibilidad y especificidad de esta herramienta. Se realizó test diagnóstico y la curva característica operativa del receptor para evaluar el área bajo la curva. Resultado: Se evaluaron 275 TP entre L1 y S1; 5 TP presentaban concordancia para una trayectoria inadecuada, mientras que 10TP, con tEMG <10mA, se encontraban correctamente posicionados. La TC-postop identificó 17 brechas pediculares no advertidas por la tEMG. La sensibilidad y la especificidad fue del 23% (IC 95%: 8-45) y 96% (IC 95%: 93-98), respectivamente, con un VPP del 33,3% y un VPN del 93,6%. El área bajo la curva fue de 0,74 (IC 95%: 0,62-0,86) con punto de corte de 24mA, que mostró una sensibilidad del 77% (IC 95%: 0,55-0,92) y una especificidad del 69% (IC 95%: 0,63-0,75). Conclusión: Dada su baja sensibilidad, no aconsejamos la tEMG como prueba única en la verificación de TP. Recomendamos la utilización de un punto de corte ≤8mA, ya que ha demostrado los niveles más altos de sensibilidad y especificidad. No recomendamos el uso de umbrales elevados para aumentar la sensibilidad.(AU)

Introduction: Instrumentation with pedicle screws (PS) can compromise the adjacent neural structures. Triggered electromyography (tEMG) is a modality of intraoperative neuromonitoring, used to assist in the placement of these. The objective of the present study is to evaluate the reliability of this tool. Method: Retrospective review of patients underwent posterior lumbar fusions from January 2017 to December 2019, correlating postoperative CT images (postop CT) with tEMG results for each PS with a threshold of 10mA, establishing sensitivity and specificity of this tool. Diagnostic test and receiver operating characteristic curve were performed to evaluate the area under the curve. Result: A total of 275 PS were evaluated between L1 to S1; 5 PS showed concordance for an inadequate trajectory, while 10PS, with tEMG <10mA, were correctly positioned. The postoperative CT identified 17 pedicle gaps not noticed by the tEMG. Sensitivity and specificity were 23% (95% CI: 8-45) and 96% (95% CI: 93-98), respectively, with a PPV of 33.3% and a NPV of 93.6%. The area under the curve was 0.74 (95% CI: 0.62-0.86) with a cut-off point of 24mA, showing a sensitivity of 77% (95% CI: 0.55-0.92) and specificity of 69% (95% CI: 0.63-0.75). Conclusion: Given its low sensitivity, we do not recommend tEMG as the sole test in the verification of PS. We recommend using a cut-off point ≤8mA as it demonstrated the highest levels of sensitivity and specificity. We do not recommend using high thresholds to increase sensitivity.(AU)

Triggered electromyography (tEMG) in the lumbar spine it's reliable? Correlation of tEMG with postoperative CT images in lumbar instrumentation / Electromiografía evocada (tEMG) en la columna lumbar. ¿Es confiable? Correlación de tEMG con imágenes de TC posoperatorias en la instrumentación lumbar

Introduction: Instrumentation with pedicle screws (PS) can compromise the adjacent neural structures. Triggered electromyography (tEMG) is a modality of intraoperative neuromonitoring, used to assist in the placement of these. The objective of the present study is to evaluate the reliability of this tool. Method: Retrospective review of patients underwent posterior lumbar fusions from January 2017 to December 2019, correlating postoperative CT images (postop CT) with tEMG results for each PS with a threshold of 10mA, establishing sensitivity and specificity of this tool. Diagnostic test and receiver operating characteristic curve were performed to evaluate the area under the curve. Result: A total of 275 PS were evaluated between L1 to S1; 5 PS showed concordance for an inadequate trajectory, while 10PS, with tEMG <10mA, were correctly positioned. The postoperative CT identified 17 pedicle gaps not noticed by the tEMG. Sensitivity and specificity were 23% (95% CI: 8-45) and 96% (95% CI: 93-98), respectively, with a PPV of 33.3% and a NPV of 93.6%. The area under the curve was 0.74 (95% CI: 0.62-0.86) with a cut-off point of 24mA, showing a sensitivity of 77% (95% CI: 0.55-0.92) and specificity of 69% (95% CI: 0.63-0.75). Conclusion: Given its low sensitivity, we do not recommend tEMG as the sole test in the verification of PS. We recommend using a cut-off point ≤8mA as it demonstrated the highest levels of sensitivity and specificity. We do not recommend using high thresholds to increase sensitivity.(AU)

Introducción: La instrumentación con tornillos pediculares (TP) puede comprometer las estructuras neurales adyacentes. La electromiografía evocada (tEMG) es una modalidad del neuromonitoreo intraoperatorio utilizada para asistir la colocación de estos. El objetivo del presente estudio es evaluar la confiabilidad de esta herramienta. Método: Revisión retrospectiva de pacientes intervenidos de artrodesis lumbar posterolateral instrumentada desde enero del 2017 hasta diciembre del 2019. Se correlacionaron las imágenes de TC postoperatorias (TC-postop) con los resultados de la tEMG para cada TP con un umbral de 10mA, y se establecieron la sensibilidad y especificidad de esta herramienta. Se realizó test diagnóstico y la curva característica operativa del receptor para evaluar el área bajo la curva. Resultado: Se evaluaron 275 TP entre L1 y S1; 5 TP presentaban concordancia para una trayectoria inadecuada, mientras que 10TP, con tEMG <10mA, se encontraban correctamente posicionados. La TC-postop identificó 17 brechas pediculares no advertidas por la tEMG. La sensibilidad y la especificidad fue del 23% (IC 95%: 8-45) y 96% (IC 95%: 93-98), respectivamente, con un VPP del 33,3% y un VPN del 93,6%. El área bajo la curva fue de 0,74 (IC 95%: 0,62-0,86) con punto de corte de 24mA, que mostró una sensibilidad del 77% (IC 95%: 0,55-0,92) y una especificidad del 69% (IC 95%: 0,63-0,75). Conclusión: Dada su baja sensibilidad, no aconsejamos la tEMG como prueba única en la verificación de TP. Recomendamos la utilización de un punto de corte ≤8mA, ya que ha demostrado los niveles más altos de sensibilidad y especificidad. No recomendamos el uso de umbrales elevados para aumentar la sensibilidad.(AU)