Navigation and Robotic Single-Position Prone LLIF: First Cases in Brazil.

OBJECTIVE: has been rapid technological advancement in navigation-guided minimally invasive surgery over the past two decades, making these advancements an invaluable aid for surgeons by essentially providing real-time virtual reconstruction of patient anatomy. The objectives of these navigation- and robot-guided procedures are to reduce the likelihood of neural and vascular injury, minimize hospitalization time, decrease bleeding and postoperative pain, shorten healing time, and lower infection rates. METHODS: A unicentric, retrospective cohort study was conducted to evaluate the preoperative and postoperative clinical and radiographic outcomes of the first Latin American patients diagnosed with lumbar degenerative disease who underwent lumbar interbody fusion at the L4-L5 level via prone-position lateral lumbar interbody fusion-single position prone access. RESULTS: A total of 80 patients (40 assisted by fluoroscopy, 40 assisted by robotics) with 320 percutaneous pedicle screws were evaluated. The primary outcomes analyzed and compared were radiation exposure per screw (seconds), skin-to-skin operative time (minutes), and recovery time (days). Secondary outcomes included lumbar pain intensity (visual analog scale), reported functional disability (Oswestry Disability Index), and any potential complications. All secondary outcomes were collected at the postoperative time. CONCLUSION: Comparing minimally invasive spine interventions with free-hand instrumentation and robotic instrumentation, a statistically significant difference was identified in radiation exposure per screw and surgical time. The literature on Cirq Robotic is limited; however, minimally invasive spine surgery with robotic assistance appears advantageous in terms of radiation exposure and surgical time.

Image Guided Interpedicular Screw Placement Simulation System for Training and Skill Evaluation. Proof of Concept.

BACKGROUND: The SpineST-01 system is an image-guided vertebrae cannulation training system. During task execution, the computer calculates performance-based metrics displaying different visual perspectives (lateral view, axial view, anteroposterior view) with the position of the instrument inside the vertebra. Finally, a report with the metrics is generated as performance feedback. METHODS: A training box holds a 3D printed spine section. The computer works with 2 orthogonally disposed cameras, tracking passive markers placed on the instrument. Eight metrics were proposed to evaluate the execution of the surgical task. A preliminary study with 25 participants divided into 3 groups (12 novices, 10 intermediates, and 3 expert) was conducted to determine the feasibility of the system and to evaluate and assess the performance differences of each group using Kruskal-Wallis analysis and Mann-Whitney U analysis. In both analyses, a P value ≤ 0.05 was considered statistically significant. RESULTS: When comparing experts versus novices and all 3 groups, statistical analysis showed significant differences in 6 of the 8 metrics: axial angle error (°), lateral angle error (°), average speed (mm/second), progress between shots (mm), Time (seconds), and shots. The metrics that did not show any statistically significant difference were time between shots (seconds), and speed between shots (mm/second). Also, the average result comparison placed the experts as the best performance group. CONCLUSIONS: Initial testing of the SpineST-01 demonstrated potential for the system to practice image-guided cannulation tasks on lumbar vertebrae. Results showed objective differences between experts, intermediates, and novices in the proposed metrics, making this system a feasible option for developing basic navigation system skills without the risk of radiation exposure and objectively evaluating task performance.

Radicular symptoms associated with extrapedicular screw placement / Sintomas radiculares associados com a colocação extrapedicular de parafusos / Síntomas radiculares asociados a la colocación de tornillos extrapediculares

ABSTRACT: Objective: Transpedicular fixation has rapidly evolved over the last 100 years. A common complication is screw misplacement which can lead to neurological deficits, vascular damage, or organ perforation. We intend to assess the correlation between screw misplacement and radicular symptoms through the Gertzbein scale. Methods: We conducted an observational longitudinal retrospective study on patients who underwent free-hand lumbar instrumentation surgery with fluoroscopy assistance. The patients were evaluated with postoperative CT scans, and screw positions were classified with the Gertzbein scale. Results: The initial sample included 99 patients who underwent surgery. Of the 317 screws placed, 201 did not show cortical damage, 105 screws exhibited variable invasion, and 11 screws displayed severe invasion. 96.5% screws were placed in the safe zone, with 8.6% of patients (n=5.0) exhibiting transitory weakness. 3.47% of screws (n=11) with severe invasion were seen in 7 patients of which two patients suffered from motor deficient and persistent radicular pain. Conclusion: It is of the utmost importance to pay attention to the precise insertion of the screws to minimize the risk of radicular manifestations. We recommend performing control CT scans after the procedure to ensure the correct insertion of the screws, and in case of finding a screw in a no-safe zone or Getsbein 3 position, considering screw repositioning due to high-risk neurologic damage is highly encouraged. Level of Evidence II; Observational Retrospective Study.

RESUMO: Objetivo: A fixação transpedicular evoluiu rapidamente nos últimos 100 anos, porém o deslocamento do parafuso é uma complicação comum que pode resultar em déficits neurológicos ou danos vasculares. Pretendemos correlacionar o deslocamento do parafuso com sintomas radiculares usando a escala de Gertzbein. Métodos: Conduzimos um estudo retrospectivo longitudinal observacional em pacientes submetidos à cirurgia de instrumentação lombar à mão livre com assistência de fluoroscopia. Os pacientes foram avaliados com tomografia computadorizada pós-operatória e as posições dos parafusos foram classificadas com a escala de Gertzbein. Resultados: A amostra inicial incluiu 99 pacientes. Dos 317 parafusos colocados, 201 não mostraram danos corticais, 105 exibiram invasão variável e 11 invasão severa. 96,5% dos parafusos foram colocados na zona segura, com 8,6% dos pacientes apresentando fraqueza transitório. 3,47% dos parafusos com invasão severa foram observados em 7 pacientes, dos quais 2 sofreram de deficiência motora e dor radicular persistente. Conclusão: É crucial prestar atenção à inserção precisa dos parafusos para minimizar o risco de manifestações radiculares. Recomendamos tomografias de controle para garantir a correta inserção dos parafusos e, se necessário, reposicionamento devido ao alto risco de dano neurológico. Nível de Evidência II; Estudo Observacional Retrospectivo.

RESUMEN: Objetivo: La fijación transpedicular ha evolucionado en los últimos 100 años. Una complicación común es el desplazamiento de tornillos, causante de déficits neurológicos o daños vasculares. Buscamos correlacionar el desplazamiento con síntomas radiculares mediante la escala de Gertzbein. Métodos: Se realizó un estudio observacional longitudinal retrospectivo de pacientes sometidos a cirugía de instrumentación lumbar a mano alzada asistida por fluoroscopia. Los pacientes fueron evaluados con tomografía computarizada postoperatoria y las posiciones de los tornillos se clasificaron con la escala de Gertzbein. Resultados: La muestra inicial incluyó 99 pacientes. De los 317 tornillos colocados, 201 no mostraron daño cortical, 105 mostraron invasión variable y 11 mostraron invasión severa. El 96,5% de los tornillos se colocaron en la zona segura, y el 8,6% de los pacientes mostraron debilidad transitoria. Se observó un 3,47% de tornillos con invasión grave en 7 pacientes, 2 de los cuales sufrieron discapacidad motora y dolor radicular persistente. Conclusión: Es crucial prestar atención a la inserción precisa de los tornillos para minimizar el riesgo de manifestaciones radiculares. Recomendamos la realización de tomografias de control para asegurar la correcta inserción de los tornillos y, en caso necesario, su recolocación debido al elevado riesgo de daño neurológico. Nivel de Evidencia II; Estudio Observacional Retrospectivo.

Lumbar arthrodesis in lateral single position: concepts, rational and clinical-functional results of 100 consecutive cases / Artrodese lombar em decúbito lateral único: conceitos, justificativas e resultados clínico-funcionais de 100 casos consecutivos / Artrodesis lumbar en posición lateral única: conceptos, justificaciones y resultados clínico-funcionales de 100 casos consecutivos

ABSTRACT Objective: Arthrodesis techniques such as anterior lumbar interbody fusion (ALIF) and lateral lumbar interbody fusion (LLIF) aim to reestablish physiological lordosis and minimize tissue damage to the paravertebral musculature. Supplementation with percutaneous pedicle screws is indicated in most cases, therefore, intraoperative changes in decubitus are necessary, generating costs and risks for the patient. This study aims to present concepts and results of a series of 100 cases of patients undergoing 360° fusion in lateral single position surgery (LSPS). Methods: retrospective analysis of databases collected between 2016 and 2021. Patients who underwent 360° fusion of the lumbar spine in single lateral decubitus to treat degenerative and infectious diseases were included. Cases with arthrodesis greater than 3 levels were excluded. Data collected include demographics, body mass index (BMI) and scores such as visual analog scale (VAS), EuroQOL 5D (EQ5D) and Oswestry disability index (ODI). Results: 100 patients were included in the study, submitted to LLIF and/or ALIF associated with percutaneous pedicle fixation. The lumbar VAS improved from 6.75 to 2.1 after 12 months, while the sciatica VAS started from 4.55 and reached 0.81 after one year. The EQ5D improved from 66.1 to 81.6 after the first year, while the ODI ranged from 28.54 to 14.18 in the same period. Conclusions: the clinical-functional results of the LSPS procedures are favorable and place the LSPS as an option to be studied, developed and practiced by spine surgery teams. Level of evidence: IV. Case series.

Resumo: Objetivo: Técnicas de artrodese como anterior lumbar interbody fusion (ALIF) e lateral lumbar interbody fusion (LLIF) tem como objetivos o reestabelecimento da lordose fisiológica e a mínima lesão tecidual da musculatura paravertebral. A suplementação com parafusos pediculares por via percutânea é indicada na maioria dos casos, sendo, portanto, necessárias mudanças de decúbito intraoperatórias, gerando custos e riscos para o paciente. Este estudo tem como objetivo apresentar conceitos e resultados de uma série de 100 casos de pacientes submetidos a fusão 360° em lateral single position surgery (LSPS). Métodos: análise retrospectiva de banco de dados coletados entre 2016 e 2021. Foram incluídos pacientes submetidos a fusão 360° da coluna lombar em decúbito lateral único para tratamento doenças degenerativas e infecciosas. Foram excluídos casos com artrodeses maiores que 3 níveis. Os dados coletados incluem demografia, índice de massa corpórea (IMC) e scores como visual analog scale (VAS), EuroQOL 5D (EQ5D) e Oswestry disability index (ODI). Resultados: 100 pacientes foram incluídos no estudo, submetidos a LLIF e/ ou ALIF associados a fixação pedicular percutânea. O VAS lombar apresentou melhora de 6,75 para 2,1 após 12 meses, já o VAS ciatalgia partiu de 4,55 e atingiu 0,81 após um ano. O EQ5D apresentou melhora de 66,1 para 81,6 após o primeiro ano, enquanto o ODI variou de 28,54 para 14,18 no mesmo período. Conclusões: os resultados clínico-funcionais dos procedimentos em LSPS se mostram favoráveis e a colocam o LSPS como uma opção a ser estudada, desenvolvida e praticada pelas equipes de cirurgia de coluna. Nível de evidência: IV. Série de casos.

Resumen: Objetivo: Las técnicas de artrodesis como la fusión intersomática lumbar anterior (ALIF) y la fusión intersomática lumbar lateral (LLIF) tienen como objetivo restablecer la lordosis fisiológica. La suplementación con tornillos pediculares percutáneos está indicada en la mayoría de los casos, por lo que son necesarios cambios en decúbito intraoperatorios, generando costos y riesgos para el paciente. Este estudio tiene como objetivo presentar conceptos y resultados de una serie de 100 casos de pacientes sometidos a fusión de 360° en cirugía de posición única lateral (LSPS). Métodos: análisis retrospectivo de bases de datos recolectadas entre 2016 y 2021. Se incluyeron pacientes que se sometieron a fusión de columna lumbar 360° en decúbito lateral y se excluyeron los casos con artrodesis mayores de 3 niveles. Los datos recopilados incluyen datos demográficos, índice de masa corporal (IMC) y puntajes como la escala analógica visual (VAS), EuroQOL 5D (EQ5D) y el índice de discapacidad de Oswestry (ODI). Resultados: 100 pacientes fueron incluidos en el estudio, sometidos a LLIF y/o ALIF asociados a fijación pedicular percutánea. La EVA lumbar mejoró de 6,75 a 2,1 a los 12 meses, mientras que la EVA de ciática partió de 4,55 y llegó a 0,81 al año. El EQ5D mejoró 66,1 a 81,6 después del primer año, mientras que el ODI varió 28,54 a 14,18 en el mismo período. Conclusiones: los resultados clínico-funcionales de los procedimientos de LSPS son favorables y a sitúan como una opción a ser estudiada, desarrollada y practicada por los equipos de cirugía de columna. Nivel de evidencia: IV. Series de casos.

Factors Affecting the Accuracy of Pedicle Screw Placement in Robot-Assisted Surgery: A Multicenter Study.

STUDY DESIGN: Retrospective multicenter. OBJECTIVE: The aim was to investigate the factors involved in, and their relative contributions to, the overall accuracy of robot-assisted pedicle screw placement. SUMMARY OF BACKGROUND DATA: Robot-assisted surgery has reportedly resulted in greater accuracy for placement of pedicle screws than conventional methods. There are many potential factors affecting the accuracy of pedicle screws placed with a robot. No study has investigated these factors in a robust way. MATERIALS AND METHODS: Radiographic and clinical data of three centers were pooled. Preoperative and postoperative computerized tomographies were obtained by all three centers to assess the accuracy of the placed screws. The primary outcome measured was accuracy of pedicle screws placed with the robot. The authors performed a multivariate regression analysis to determine the significant patient-related and screw-related variables and their relative contribution to the overall accuracy. In addition, an ordinal regression analysis was conducted to investigate the effects of different variables on accuracy of robot-placed screws graded by Gertzbein-Robbins grading system (GRS). RESULTS: The total contribution of all studied variables to overall accuracy variation as measured by offsets between the placed and planned screws was only 18%. Obesity, long constructs, female gender, surgeon, and vertebral levels were among the factors that had small contributions to the different screw offsets. For GRS grades, significant variables were gender (Log odds: 0.62, 95% CI: 0.38-0.85), age (Log odds: 0.02, 95% CI: 0.01-0.03), length of constructs (Log odds: 0.07, 95% CI: 0.02-0.11), screw diameter (Log odds: 0.55, 95% CI: 0.39-0.71), and length of the screws (Log odds: 0.03, 95% CI: 0.01-0.05). However, these variables too, regardless of their significant association with the accuracy of placed screws, had little contribution to overall variability of accuracy itself (only about 7%). CONCLUSION: The accuracy of screws placed with robotic assistance, as graded by GRS or measured offsets between planned and placed screw trajectories, is minimally affected by different patient-related or screw-related variables due to the robustness of the robotic navigation system used in this study. LEVEL OF EVIDENCE: Level III.

Preoperative MRI Reliably Predicts Pedicle Dimensions on Intraoperative CT Images in Structural Main Thoracic Curves in Patients With Adolescent Idiopathic Scoliosis.

STUDY DESIGN: A retrospective comparative study. OBJECTIVE: The aim of this study was to compare the length and diameter of thoracic pedicles in patients with adolescent idiopathic scoliosis (AIS) as measured on preoperative magnetic resonance imaging (pMRI) to intraoperative computed tomography (iCT) scan. SUMMARY OF BACKGROUND DATA: Optimally sized pedicle screw placement during instrumented posterior spinal fusion for AIS can maximize correction and minimize screw pullout. While iCT-guided navigation can quickly estimate screw position and size, this technology is not universally available. Many surgeons utilize pMRI, when obtained, to estimate screw sizes. Data comparing these measurements on pMRI and iCT is limited. We hypothesized that in patients with surgical magnitude AIS, pedicle length, and diameter measured on pMRI would have at least moderate reliability compared to those made on iCT images. MATERIALS AND METHODS: The pMRI and iCT for 60 patients with structural thoracic curves who underwent posterior spinal fusion for AIS at a single center between 2009 and 2017 were analyzed. Bilateral T5-T12 vertebral levels were evaluated for pedicle chord length and pedicle isthmic diameter on both pMRI and iCT. Between-study reliability and interrater reliability was evaluated for each level of the thoracic spine. RESULTS: There is good reliability for pedicle length [intraclass correlation coefficient (ICC)=0.8, 95% confidence interval (CI): 0.78-0.83] and diameter (ICC=0.86, 95% CI: 0.84-0.88) between pMRI and iCT. When assessed by level, T6 has the lowest reliability for length (ICC=0.52, 95% CI: 0.33-0.67) and diameter (ICC=0.55, 95% CI: 0.35-0.69). Interrater reliability ranged from moderate-to-good reliability for all pedicle measurements for both length and diameter on pMRI and iCT. CONCLUSION: Pedicle measurements made on pMRI may be used with reasonable reliability to predict pedicle dimensions visualized on iCT, allowing surgeons to preoperatively plan pedicle screw sizes based off magnetic resonance imaging.

The Influence of Thread Tap Mismatch on Pedicle Screw Pullout Strength / A influência da incompatibilidade do macho de rosca na resistência à extração do parafuso pedicular

Abstract Objective We aimed to study the "in vitro" pullout strength of SpineGuard/Zavation Dynamic Surgical Guidance Z-Direct Screw (DSG Screw, SpineGuard Inc, Boulder, Colorado, USA), a screw designed to be inserted using a direct insertion technique. Methods Dynamic Surgical Guidance Screws of 5.5 and 6.5 mm were introduced into polyurethane blocks with a density of 10 PCF (0,16g/cm3). According to the experimental group, screws were inserted without pilot hole, with pilot without tapping, undertapping and line-to-line tapping. Screw pullout tests were performed using a universal test machine after screw insertion into polyurethane blocks. Results Screws inserted directly into the polyurethane blocks without pilot hole and tapping showed a statistically higher pullout strength. Insertion of the screw without tapping or with undertapping increases the pullout screw strength compared with lineto-line tapping. Conclusion Dynamic Surgical Guidance Screw showed the highest pullout strength after its insertion without pilot hole and tapping.

Resumo Objetivo Nosso objetivo foi estudar a resistência à extração "in vitro" do parafuso SpineGuard/Zavation Dynamic Surgical Guidance Z-Direct (Parafuso DSG Guia Cirúrgico Dinâmico, SpineGuard Inc, Boulder, Colorado, USA), um parafuso projetado para ser inserido utilizando a técnica de inserção direta. Métodos Os parafusos DSG de 5,5 e 6,5 mm foram introduzidos em blocos de poliuretano com densidade de 10 PCF (0,16g/cm3). De acordo com o grupo experimental, os parafusos foram inseridos sem um orifício piloto, com um orifício piloto sem o macheamento, com macheamento e com macheamento linha a linha. Os testes de extração do parafuso foram realizados em uma máquina de teste universal, após a inserção do parafuso em blocos de poliuretano. Resultados Os parafusos inseridos diretamente nos blocos de poliuretano sem o orifício piloto e o macheamento mostraram uma resistência à extração estatisticamente maior. A inserção do parafuso sem o macheamento ou com o macho de menor diâmetro aumenta a resistência à extração do parafuso em comparação com o macheamento linha a linha. Conclusão O parafuso DSG apresentou a maior resistência à extração após a inserção sem o orifício piloto e o macheamento.

Power-assisted Pedicle Screw Technique Protects Against Risk of Surgeon Overuse Injury: A Comparative Electromyography Study of the Neck and Upper Extremity Muscle Groups in a Simulated Surgical Environment.

STUDY DESIGN: Cadaveric. OBJECTIVE: The aim of this study was to quantify the amplitude and duration of surgeons' muscle exertion from pedicle cannulation to screw placement using both manual and power-assisted tools in a simulated surgical environment using surface electromyography (EMG). SUMMARY OF BACKGROUND DATA: A survey of Scoliosis Research Society members reported rates of neck pain, rotator cuff disease, lateral epicondylitis, and cervical radiculopathy at 3 ×, 5 ×, 10 ×, and 100â€Š× greater than the general population. The use of power-assisted tools in spine surgery to facilitate pedicle cannulation through screw placement during open posterior fixation surgery may reduce torque on the upper limb and risk of overuse injury. METHODS: Pedicle preparation and screw placement was performed from T4-L5 in four cadavers by two board-certified spine surgeons using both manual and power-assisted techniques. EMG recorded muscle activity from the flexor carpi radialis, extensor carpi radialis, biceps, triceps, deltoid, upper trapezius, and neck extensors. Muscle activity was reported as a percentage of the maximum voluntary exertion of each muscle group (%MVE) and muscle exertion was linked to low- (0-20% MVE), moderate- (20%-45% MVE), high- (45%-70% MVE) and highest- (70%-100% MVE) risk of overuse injury based on literature. RESULTS: Use of power-assisted tools for pedicle cannulation through screw placement maintains average muscle exertion at low risk for overuse injury for every muscle group. Conversely with manual technique, the extensor carpi radialis, biceps, upper trapezius and neck extensors operate at levels of exertion that risk overuse injury for 50% to 92% of procedure time. Powerassisted tools reduce average muscle exertion of the biceps, triceps, and deltoid by upwards of 80%. CONCLUSION: Power-assisted technique protects against risk of overuse injury. Elevated muscle exertion of the extensor carpi radialis, biceps, upper trapezius, and neck extensors during manual technique directly correlate with surgeons' self-reported diagnoses of lateral epicondylitis, rotator cuff disease, and cervical myelopathy.Level of Evidence: N/A.

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

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.

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.

Morphometric description of thoracic vertebral pedicles in adult Malawian cadavers and implications for transpedicula spine fixation / Descripción morfometrica de los pedículos vertebrales torácicos en cadáveres de Malawi adultos e implicaciones para la fijación transpedicular de la columna

SUMMARY: Thoracic pedicles are important during the surgical repair of the thoracic spine deformities. Individuals show considerable differences in the asymmetric dimensions of the thoracic pedicles across populations. The purpose of this study was to determine the thoracic pedicle size and angle in adult Malawian cadavers and to suggest the clinical implications associated particularly the transpedicular fixation of spinal deformities. Adult thoracic vertebra from undetermined sex specimens (n=227) from the skeletal collection in the Anatomy Division, Biomedical Sciences Department, College of Medicine, University of Malawi were measured to assess the pedicle width, pedicle height, chord length, transverse diameter, interpedicular distance, transverse and sagittal pedicle angles. The mean pedicle width was 4.71 ± 1.83 mm (left side) and 4.82 ± 1.77 mm (right side) and the mean pedicle height was 12.63 ± 2.61 mm (left side) and 12.60 ± 2.54 mm (right side). The mean transverse pedicle angle was 12.22 ± 2.30 degrees (left side) and 12.46 ± 2.34 degrees (right side). The mean sagittal pedicle angle was 9.24 ± 2.67 degrees (left side) and 9.40 ± 2.76 degrees (right side). The mean interpedicular distance was 16.67 ± 2.23 mm. Our sample population generally showed smaller thoracic pedicle dimensions than those reported in other populations. Prior knowledge of the variations regarding the thoracic pedicle dimensions is vital for the determination of the pedicle screw size and design. Most importantly the information helps surgeons during preoperative planning of the transpedicular thoracic spine fixation and radiological interpretation.

RESUMEN: Los pedículos de las vértebras torácicas son importantes durante la reparación quirúrgica de las deformidades de la columna torácica. Los individuos muestran diferencias considerables en las dimensiones asimétricas de las vértebras torácicas entre poblaciones. El propósito de este estudio fue determinar el tamaño y el ángulo los pedículos de las vértebras torácicas en cadáveres de Malawi adultos y sugerir las implicaciones clínicas asociadas a la fijación transpedicular de las deformidades espinales. Se midieron 227 vértebras torácicas de muestras de individuos de sexo indeterminado de la colección esquelética en la División de Anatomía, Departamento de Ciencias Biomédicas, Facultad de Medicina, Universidad de Malawi para evaluar el ancho del pedículo, la altura del pedículo, la longitud, el diámetro transversal, distancia interpedicular y ángulos pediculares transversales y sagitales. El ancho medio del pedículo fue de 4,71 ± 1,83 mm (lado izquierdo) y 4,82 ± 1,77 mm (lado derecho) y la altura media del pedículo fue de 12,63 ± 2,61 mm (lado izquierdo) y 12,60 ± 2,54 mm (lado derecho). El ángulo pedicular transverso medio fue de 12,22 ± 2,3 grados (lado izquierdo) y 12,46 ± 2,34 grados (lado derecho). El ángulo pedicular sagital medio fue de 9,24 ± 2,67 grados (lado izquierdo) y 9,40 ± 2,76 grados (lado derecho). La distancia interpedicular media fue de 16,67 ± 2,23 mm. La población de esta muestra mostró dimensiones de los pedículos de las vértebras torácicas generalmente más pequeñas que las informadas en otras poblaciones. El conocimiento previo de las variaciones con respecto a las dimensiones de los pedículos de las vértebras torácicas es vital para la determinación del tamaño y diseño del tornillo pedicular. Lo más importante es que la información ayuda a los cirujanos durante la planificación preoperatoria para la fijación transpedicular de la columna torácica y su interpretación radiológica.

Diagnostic Accuracy of Thresholds Less Than or Equal to 8 mA in Pedicle Screw Testing During Lumbar Spine Procedures to Predict New Postoperative Lower Extremity Neurological Deficits.

STUDY DESIGN: Retrospective observational study. OBJECTIVE: It has been shown that pedicle screw stimulation thresholds less than or equal to 8 mA yield a very high diagnostic accuracy of detecting misplaced screws in spinal surgery. In our study, we determined clinical implications of low stimulation thresholds. SUMMARY OF BACKGROUND DATA: Posterior lumbar spinal fusions (PSF), using pedicle screws, are performed to treat many spinal pathologies, but misplaced pedicle screws can result in new postoperative neurological deficits. METHODS: Patients with pedicle screw stimulation testing who underwent PSF between 2010 and 2012 at the University of Pittsburgh Medical Center (UPMC) were included in the study. We evaluated the sensitivity, specificity, and diagnostic odds ratio (DOR) to determine how effectively low pedicle screw responses predict new postoperative lower extremity neurological deficits. RESULTS: One thousand one hundred seventy nine eligible patients underwent 8584 pedicle screw stimulations with lower extremity somatosensory evoked potentials (LE SSEP) monitoring for lumbar fusion surgery. One hundred twenty one of these patients had 187 pedicle screws with a stimulation response at a threshold less than or equal to 8 mA. Smoking had a significant correlation to pedicle screw stimulation less than or equal to 8 mA (P = 0.012). A threshold of less than or equal to 8 mA had a sensitivity/specificity of 0.32/0.90 with DOR of 4.34 [1.83, 10.27] and an area under the ROC curve (AUC) of 0.61 [0.49, 0.74]. Patients with screw thresholds less than or equal to 8 mA and abnormal baselines had a DOR of 9.8 [95% CI: 2.13-45.17] and an AUC of 0.73 [95% CI: 0.50-0.95]. CONCLUSION: Patients with pedicle screw stimulation thresholds less than or equal to 8 mA are 4.34 times more likely to have neurological clinical manifestations. Smoking and LE deficits were shown to be significantly correlated with pedicle screw stimulation thresholds less than or equal to 8 mA. Low stimulation thresholds result in a high specificity of 90%. Pedicle screw stimulation less than or equal to 8 mA can serve as an accurate rule in test for postoperative neurological deficit, warranting reevaluation of screw placement and/or replacement intraoperatively.Level of Evidence: 3.

Minimally invasive lumbar arthrodesis and percutaneous pedicle screws: a systematic review / Artrodese lombar minimamente invasiva e parafusos pediculares percutâneos: revisão sistemática / Artrodesis lumbar mínimamente invasiva y tornillos pediculares percutáneos: revisión sistemática

ABSTRACT A systematic review of the literature was performed in order to organize, evaluate, and select evidences available about the safety and efficacy of minimally invasive percutaneous arthrodesis with percutaneous pedicle screws in the treatment of patients with degenerative disc disease (and other spinal pathologies) as compared to conventional arthrodesis. PubMed, EMBASE and Cochrane Library databases were consulted to locate clinical trials and case reports/case series published in English between 2014 and 2019. After selection according to the inclusion/exclusion criteria, 21 of the 197 articles identified were chosen for a complete reading and used for the present review. Although the level of evidence of most of the studies included made the demonstration of efficacy and superiority among the surgical techniques reviewed difficult, the findings related to the minimally invasive procedure indicate a safe and reliable approach for the treatment of lumbar diseases. Level of evidence II; Systematic review of literature.

RESUMO A revisão sistemática da literatura foi realizada com o objetivo de organizar, avaliar e selecionar evidências a respeito da segurança e eficácia da artrodese percutânea minimamente invasiva com parafusos pediculares percutâneos no tratamento de pacientes com doença degenerativa de disco (e outras patologias da coluna), em comparação com a artrodese convencional. Foram consultadas as bases de dados PubMed, EMBASE e Biblioteca Cochrane para localizar ensaios clínicos e relatos/séries de casos publicados em inglês entre 2014 e 2019. Dentre 197 estudos identificados, depois de seleção usando critérios de inclusão/exclusão, 21 artigos foram escolhidos para leitura na íntegra e usados na presente revisão. Apesar do nível de evidência da maioria dos estudos incluídos dificultar a demonstração de eficácia e superioridade entre as técnicas cirúrgicas revisadas, os achados referentes ao procedimento minimamente invasivo apontam para uma abordagem segura e confiável para o tratamento de doenças lombares. Nível de evidência II; Revisão sistemática da literatura.

RESUMEN La revisión sistemática de la literatura fue realizada con el objetivo de organizar, evaluar y seleccionar evidencias al respecto de la seguridad y eficacia de la artrodesis percutánea mínimamente invasiva con tornillos pediculares en el tratamiento de pacientes con enfermedad degenerativa de disco (y otras patologías de la columna) en comparación con la artrodesis convencional. Fueron consultadas las bases de datos PubMed, EMBASE y Biblioteca Cochrane para localizar ensayos clínicos y relatos/series de casos publicados en inglés entre 2014 y 2019. Entre 197 estudios identificados, después de selección usando criterios de inclusión/exclusión, fueron escogidos 21 artículos para lectura integral y usados en la presente revisión. A pesar de que el nivel de evidencia de la mayoría de los estudios incluidos dificulte la demostración de eficacia y superioridad entre las técnicas quirúrgicas revisadas, los hallazgos referentes al procedimiento mínimamente invasivo apuntan hacia un abordaje seguro y confiable para el tratamiento de enfermedades lumbares. Nivel de evidencia II; Revisión sistemática de la literatura.

Enxerto pediculado de omento maior como adjuvante no tratamento de osteomielite de tíbia em cão - relato de caso / [Greater omentum pedicle flap as adjunctive treatment of tibial osteomyelitis in a dog - case report]

A osteomielite é um desafio terapêutico em ortopedia, capaz de retardar ou mesmo impedir a consolidação óssea. O omento, há anos, tem sido empregado como alternativa em diferentes procedimentos cirúrgicos, por sua capacidade, entre outras, de angiogênese, sendo aplicado na ortopedia veterinária quando há o risco de não união óssea. Neste caso, um cão Fila Brasileiro foi submetido à realização de enxerto com retalho pediculado de omento maior, após osteomielite resistente presente em osteossíntese de fratura múltipla de tíbia aberta grau II. Durante 16 dias, manteve-se a comunicação do retalho, mas, diante do risco de peritonite, o pedículo foi seccionado. Numa sequência de intervenções cirúrgicas, após 89 dias, houve cicatrização óssea e remissão da osteomielite, mesmo na presença de bactérias multirresistentes. Neste relato, o omento foi efetivo como terapia adjuvante no tratamento da osteomielite e garantiu o retorno da função do membro.(AU)

Osteomyelitis is a therapeutic challenge in orthopedics, capable of delaying or even preventing bone healing. The omentum has been used in different surgical procedures as an alternative for its capacity, among others, of angiogenesis, being applied in veterinary orthopedics, when there is a risk of non-union of bone. In this case, a Brazilian row dog was submitted to grafting with pedicle flap of greater omentum, after resistant osteomyelitis present in open fracture osteosynthesis of open tibia grade II. For 16 days the communication of the flap was maintained, but at the risk of peritonitis, the pedicle was sectioned. In a sequence of surgical interventions, after 89 days, there was bone healing and remission of osteomyelitis, even in the presence of multi-resistant bacteria. In this report, the omentum was effective as adjuvant therapy in the treatment of osteomyelitis and guaranteed the return of limb function.(AU)

The Role of Pedicle Screw Surface on Insertion Torque and Pullout Strength / Influência da superfície dos parafusos pediculares no torque de inserção e resistência ao arrancamento

Abstract Objective Compare by mechanical tests the pullout resistance and the insertion torque of rough and smooth pedicle screws. Methods Pedicle screws with rough surface and smooth surface, with diameters of 4.8; 5.5 and 6.5 mm, were inserted in polyurethane blocks with density of 10 PCF (0.16 g/cm3). Insertion torque and pullout strength were assessed. Results The pullout strength of the rough surface and smooth surface screws did not differ, except in the group of 4.8 mm diameter screws. In this group, the rough surface screws showed greater resistance to pullout. Conclusion Pedicle screws with a rough surface did not show increased pullout resistance in the acute phase of their insertion in polyurethane blocks compared to smooth surface screws. The rough surface screws had a higher insertion torque than the smooth surface screws, depending on the diameter of the screw and the preparation of the pilot hole.

Resumo Objetivo Comparar por testes mecânicos a resistência ao arrancamento e o torque de inserção do parafuso pedicularjateado e liso. Métodos Parafusos pediculares de superfície áspera e de superfície lisa com diâmetros de 4,8; 5,5 e 6,5 mm foram inseridos em blocos de poliuretano com densidade de 10 PCF (0,16 g/cm3). O torque de inserção e a força de arrancamento foram avaliados. Resultados A força de arrancamento dos parafusos de superfície áspera e de superfície lisa não diferiu, exceto no grupo de parafusos com 4,8 mm de diâmetro. Nesse grupo, os parafusos de superfície áspera apresentaram maior resistência ao arrancamento. Conclusão Os parafusos pediculares de superfície áspera não apresentaram aumento da resistência ao arrancamento na fase aguda de sua inserção em blocos de poliuretano em relação aos parafusos de superfície lisa. Os parafusos de superfície áspera apresentaram maior torque de inserção que os parafusos de superfície lisa, dependendo do diâmetro do parafuso e da preparação do furo piloto.

Pedicle Screws and Facet Violation - The importance of the Angle between the Facet and the Screw / Parafusos pediculares e violação facetária - A importância do ângulo entre a faceta e o parafuso

Abstract Objective To verify whether, regardless of the screw placement technique, there is a safe distance or angle in relation to the facets that can prevent violation of the facet joint when the screws are placed. Methods Retrospective, single, comparative, non-randomized center. We evaluated by axial computed tomography: the angle of the screw/rod in relation to the midline, the angle of the center of the facets in relation to the midline, the distance between the head of the screw/rod to the midline, and the distance from the center of the facets to the midline; the violation of the facet joint will be evaluated in a gradation of 0 to 2. Also will be measured the difference between the angle os the facets and the angle of the screws (Δ Angle) and, the difference between the facet distance and the screw distance (Δ Distance). Results A total of 212 patients and 397 facets were analyzed (196 on the left and 201 on the right). Of these, 303 were not violated (grade 0), corresponding to 76,32%, and 94 suffered some type of violation (grade 1 and 2), corresponding to 23,68%. The mean of Δ angle was 9.87° +/− 4.66° (grade 0), and of 3.77° +/− 4.93° in facets (grade 1 and 2) (p< 0.001), and the Δ mean distance in cases in which there was no violation was 0.94 arbitrary units (a.u.) +/− 0.39 a.u., while the Δ distance in G1 and G2 cases was 0.56 a.u. +/− 0.25 a.u. (p< 0.001). Conclusion The measurements of angle and distance between facet and screw can help in the placement of screws. These parameters can be used as safety measures with the most frequent use of surgical navigation techniques.

Resumo Objetivo Verificar se, independente da técnica de colocação do parafuso, há uma distância ou angulação segura em relação as facetas para que os parafusos sejam colocados de modo a evitar a violação da articulação facetária. Métodos Estudo retrospectivo, comparativo, não randomizado, em centro único. Foram avaliados em tomografia computadorizada axial: o ângulo do parafuso/barra em relação a linha média, o ângulo do centro das facetas em relação a linha média, a distância entre a cabeça do parafuso/barra até a linha média, e a distância do centro das facetas até a linha média; a violação da articulação facetária será avaliada em uma gradação de 0 a 2. Serão também calculados a diferença entre o ângulo do parafuso e ângulo da faceta (Δ Ångulo) e também a diferença entre a distância da faceta e a distância do parafuso (Δ Distância). Resultados Um total de 212 pacientes e 397 facetas foram analisados (196 do lado esquerdo e 201 do lado direito). Destes, 303 foram não violados (grau 0), correspondendo a 76,32%, e 94 sofreram algum tipo de violação (grau 1 e 2), correspondendo a 23,68%. A média do Δ ângulo foi de 9,87° +/− 4,66° (grau 0) e de 3,77° +/− 4,93° em facetas (grau 1 e 2) (p< 0.001), e o Δ distância médio nos casos em que não houve violação foi de 0,94 unidades aleatórias (u.a.) +/− 0,39 u.a., enquanto o Δ distância de casos G1 e G2 foi de 0,56 u.a. +/− 0,25 u.a. (p< 0.001). Conclusão As medidas de ângulo e distância entre faceta e parafuso, podem auxiliar na colocação de parafusos. Esses parâmetros podem ser utilizados como medidas de segurança com o uso mais frequentes das técnicas de navegação cirúrgica.

Diagnostic accuracy of perioperative electromyography in the positioning of pedicle screws in adolescent idiopathic scoliosis treatment: a cross-sectional diagnostic study.

BACKGROUND: To investigate in the conventional techniques of the pedicle screws using triggered screw electromyography (t-EMG), considering different threshold cutoffs: 10, 15, 20 25 mA, for predicting pedicle screw positioning during surgery of the adolescent with idiopathic scoliosis (AIS). METHODS: Sixteen patients (4 males, 12 females, average age 16.6 years) were included, with an average curve magnitude of 50 degrees and placement of 226 pedicle screws. Each screw was classified as "at risk for nerve injury" (ARNI) or "no risk for nerve injury" (NRNI) using CT and the diagnostic accuracy of EMG considering different threshold cutoffs (10,15, 20 and 25 mA) in the axial and Sagittal planes for predicting screw positions ARNI was investigated. RESULTS: The EMG exam accuracy, in the axial plane, 90.3% screws were considered NRNI. In the sagittal plane, 81% pedicle screws were considered NRNI. A 1-mA decrease in the EMG threshold was associated with a 12% increase in the odds of the screw position ARNI. In the axial and sagittal planes, the ORs were 1.09 and 1.12, respectively. At every threshold cutoff evaluated, the PPV of EMG for predicting screws ARNI was very low in the different threshold cutoff (10 and 15); the highest PPV was 18% with a threshold cutoff of 25 mA. The PPV was always slightly higher for predicting screws ARNI in the sagittal plane than in the axial plane. In contrast, there was a moderate to high NPV (78-93%) for every cutoff analyzed. CONCLUSIONS: EMG had a moderate to high accuracy for positive predicting value screws ARNI with increase threshold cutoffs of 20 and 25 mA. In addition, showed to be effective for minimizing false-negative screws ARNI in the different threshold cutoffs of the EMG in adolescent with idiopathic scoliosis (AIS).

The Impact of Posterior Spinal Fusion (PSF) on Coronal Balance in Adolescent Idiopathic Scoliosis (AIS): A New Classification and Trends in the Postoperative Period.

INTRODUCTION: One of the primary goals of scoliosis surgery is to balance the head over the pelvis (or avoid creating imbalance). Historically, a normal coronal balance was defined as the C7 plumb line (C7PL) within 2 cm of the central sacral vertical line (CSVL); however, there is limited published information regarding the speed/magnitude and success/failure of balancing, rebalancing, or unbalancing in the postoperative period. The purpose of this study is to classify and quantify coronal plane balance postoperatively in adolescent idiopathic scoliosis when using pedicle screw instrumentation. METHODS: Evaluated patients with adolescent idiopathic scoliosis who had a posterior spinal fusion withstanding 2-view, posteroanterior and lateral radiographs of the entire spine performed at first erect visit, 6, 12, and 24 months. To measure coronal balance, a C7PL was measured and compared with the CSVL. A negative value denotes the leftward deviation of the C7PL and a positive value a rightward deviation. The authors then created a novel coronal balance classification system. RESULTS: A total of 954 patients met the inclusion criteria. There was a strong trend toward improving coronal balance, especially between first erect and 6 months; the proportion of out of balance patients declined throughout the 2-year period: preoperative 372 of 954 (39%), first erect 297 of 954 (31.1%), 6 months 167 of 954 (17.5%), 1 year 136 of 954 (14.3%), and 2 years 115 of 954 (12.0%). Analyzing the patients most out of balance immediately after posterior spinal fusion, 35 of 50 (70%) in group 3 regained balance by 2 years. Out of the remaining 15 patients, 12 corrected to group 1 (24%), 2 patients to group 2 (4%), and 1 patient remained in group 3 (2%). CONCLUSIONS: This large, longitudinal postoperative study of coronal balance documents a strong trend toward postoperative rebalancing, with the largest gains between first erect image and 6 months. The 31% of patients out of balance at first erect declined to only 12.1% at 2 years.

Pedicle morphology in scoliosis: classification agreement for pre-operative evaluation / Morfologia do pedículo na escoliose: concordância na classificação para avaliação pré-operatória / Morfología del pedículo en la escoliosis: concordancia de clasificación para evaluación prequirúrgica

ABSTRACT Objectives Although Watanabe morphological classification is well known, there is no consensus of its use among spine surgeons. We propose an analysis of the Watanabe classification by three observers, one senior and two recently graduated orthopedic spine surgeons, and its applicability in pre-operative evaluation. Methods An intraobserver and interobserver analysis of the classifications of 937 thoracic pedicles among 55 scoliosis patients treated surgically in two institutions. The average age at time of surgery was 16.3 years (10- 50 years). The etiologies of the scoliosis were: idiopathic (n= 47), congenital (n=4), syndromic (n= 3) and neuromuscular (n=1). The mean Cobb angle was 67 degrees (41- 120º). The evaluation of the thoracic pedicle was performed using pre-operative CT images. Results A total of 937 pedicles were classified by three observers with percentages of 47.5% type A, 28.6% type B, 17.1% type C and 6.9% type D for the total pedicles, convex and concave. Intraobserver agreement was fair to almost perfect (kappa 0.34 to 0.92) and interobserver agreement was fair to moderate (kappa 0.33 to 0.59) with statistical significance of p<0.001. Conclusion Watanabe classification remains a good method for predicting intraoperative difficulties, and has better agreement as the surgeon becomes more experienced. Level of evidence II; Prognostic Studies.

RESUMO Objetivo A classificação morfológica dos pedículos descrita por Watanabe, apesar de bem conhecida, não é consenso entre os cirurgiões de coluna. Propomos uma análise da classificação por três observadores, um sênior e dois cirurgiões de coluna recém-graduados, e sua aplicabilidade na avaliação pré-operatória. Métodos Foi realizada uma análise intraobservador e interobservador das classificações de Watanabe de 937 pedículos em 55 pacientes com escoliose, tratados cirurgicamente em duas instituições. A média de idade no momento da cirurgia foi de 16,3 anos (10 a 50 anos). As etiologias da escoliose foram: idiopática (n = 47), congênita (n = 4), sindrômica (n = 3) e neuromuscular (n = 1). O ângulo médio de Cobb foi de 67 graus (41º a 120º). A avaliação dos pedículos torácicos foi realizada com imagens pré-operatórias de tomografia computadorizada. Resultados Três observadores classificaram 937 pedículos côncavos e convexos, evidenciando 47,5% do tipo A; 28,6% do tipo B; 17,1% do tipo C e 6.9% do tipo D. A concordância intraobservador foi de razoável a quase perfeita (kappa 0,34 a 0,92) e concordância interobservador foi de razoável a moderada (kappa 0,33 a 0,59), com significância estatística de p < 0,001. Conclusões A classificação de Watanabe pode ser considerada um bom método para prever dificuldades intraoperatórias e apresenta melhor concordância à medida que o cirurgião se torna mais experiente. Nível de Evidência II; Estudos Prognósticos.

RESUMEN Objetivo La clasificación morfológica de los pedículos descrita por Watanabe, a pesar de ser bien conocida, no es consenso entre los cirujanos de columna. Proponemos un análisis de la clasificación por 3 observadores, un sénior y dos cirujanos de columna recién graduados, y su aplicabilidad en la evaluación prequirúrgica. Método Fue realizado un análisis intraobservador e interobservador de las clasificaciones de Watanabe de 937 pedículos en 55 pacientes con escoliosis, tratados quirúrgicamente en dos instituciones. El promedio de edad en el momento de la cirugía fue de 16,3 años (10-50 años). Las etiologías de la escoliosis fueron: idiopática (n=47), congénita (n=4), sindrómica (n=3) y neuromuscular (n=1). El ángulo promedio de Cobb fue de 67 grados (41º a 120º). La evaluación de los pedículos torácicos fue realizada con imágenes prequirúrgicas de tomografía computada. Resultados Tres observadores clasificaron 937 pedículos cóncavos y convexos, evidenciando 47,5% tipo A, 28,6% tipo B, 17,1% tipo C y 6,9% tipo D. La concordancia intraobservador fue de razonable a casi perfecta (kappa 0,34 a 0,92)y la concordancia interobservador fue de razonable a moderada (kappa 0,33 a 0,59) con una significancia estadística de p<0,001. Conclusiones La clasificación de Watanabe puede ser considerada un buen método para prever dificultades intraquirúrgicas y presenta mejor concordancia a medida que el cirujano se vuelve más experimentado. Nivel de Evidencia II; Estudios Pronósticos.

Intra- and interobserver analysis of pedicle screw placement in scoliosis correction / Análise intra e interobservador de posicionamento de parafusos pediculares em correção de escoliose / Análisis intra e interobservador de posicionamiento de tornillos pediculares en corrección de escoliosis

ABSTRACT Objective To establish the statistical interobserver and intraobserver concordance of thoracic pedicle screw placement in scoliosis surgery, with a 4-week interval between the two analyses. Methods Of 55 patients that evaluated the intra- and interobserver concordances of the screw positions (according to the Abul-Kasim classification) using the Kappa coefficient. Results The intraobserver concordance ranged from a Kappa coefficient of 0.516 to 0.889 ("moderate" to "almost perfect") between the two analyses performed four weeks apart. Interobserver concordance ranged from 0.379 to 0.633 ("reasonable" to "strong"). Conclusion The intraobserver concordance was always greater than the interobserver concordance. No concordance coefficient was classified as "insignificant" or "weak". Level of Evidence III; Retrospective study.

RESUMO Objetivo Estabelecer a concordância estatística interobservadores e intraobservadores do posicionamento de parafusos pediculares torácicos em cirurgia de escoliose, com intervalo de quatro semanas entre as duas análises. Métodos Com 55 pacientes, que avalia as concordâncias intra e interobservador da posição dos parafusos (segundo a classificação de Abul-Kasim), utilizando o coeficiente de Kappa. Resultados A concordância intraobservador variou entre 0,516 e 0,889 ("moderada" a "quase perfeita") de coeficiente Kappa, entre análises com intervalo de quatro semanas. A concordância interobservador variou entre 0,379 e 0,633 ("razoável" a "forte"). Conclusões A concordância intraobservador foi sempre maior que a interobservador. Nenhum coeficiente de concordância foi classificado como "insuficiente" ou "fraco". Nível de Evidência III; Estudo retrospectivo.

RESUMEN Objetivo Establecer la concordancia estadística interobservadores e intraobservadores del posicionamiento de tornillos pediculares torácicos en cirugía de escoliosis, con intervalo de cuatro semanas entre los dos análisis. Métodos Estudio de cohorte retrospectivo (nivel con 55 pacientes, que evalúa las concordancias intra e interobservador de la posición de los tornillos (según la clasificación de Abul-Kasim), usando el coeficiente de Kappa. Resultados La concordancia intraobservador varió entre 0,516 y 0,889 ("moderada" a "casi perfecta"), de coeficiente Kappa, entre análisis con intervalo por 4 semanas. La concordancia interobservador varió entre 0,379 y 0,633 ("razonable" a "fuerte"). Conclusiones La concordancia intraobservador fue siempre mayor que la interobservador. Ningún coeficiente de concordancia fue clasificado como "insuficiente" o "débil". Nivel de Evidencia III; Estudio retrospectivo.