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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.

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.

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.

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

OBJETIVO: Demostrar si la técnica de estimulación eléctrica permite la detección de la mal posición medial de los tornillos pediculares torácicos. RESULTADOS: Se analizaron 421 tornillos torácicos. Tuvimos alertas a la estimulación en 25 (5,93%) de los casos. A todos los pacientes se les realizó radiografía posoperatoria demostrando 22 tornillos (5,2%) medializados. Realizamos TAC en 17 pacientes (37%), con ningún tornillo en posición 1 y 10 tornillos en posición 2 (8,5%). Se consideraron tornillos medializados los que tenían respuesta positiva a estimulación inferior a 6 mA. CONCLUSIONES: la estimulación eléctrica nos ha permitido reducir el riesgo de posición medial de los tornillos torácicos, minimizando además el uso de radiografía intraoperatoria.OBJETIVO: Demonstrar se a técnica de estimulação elétrica permite a detecção de mal posicionamento medial dos parafusos pediculares torácicos. RESULTADOS: Foram analisados 421 parafusos torácicos. Os alertas da estimulação ocorreram em 25 (5,93%) dos casos. Todos os pacientes foram submetidos à radiografia pós-operatória que demonstrou 22 parafusos (5,2%) medializados. Realizamos TC axial em 17 pacientes (37%), e não se encontrou nenhum parafuso na posição 1, sendo que 10 parafusos estavam na posição 2 (8,5%). Foram considerados parafusos medializados os que apresentaram resposta positiva à estimulação inferior a 6 mA. CONCLUSÕES: a estimulação elétrica permitiu a redução de risco de posição medial dos parafusos torácicos, minimizando o uso de radiografias intraoperatórias.OBJECTIVE: To demonstrate that the electrical stimulation technique allows the detection of medial malpositioning of thoracic pedicle screws. RESULTS: We analyzed 421 thoracic screws. Stimulation alerts occurred in 25 (5.93%) cases. All patients underwent postoperative radiographs showing 22 medialized screws (5.2%). Axial CT scans were performed on 17 patients (37%), and no screw was found in position 1 and 10 of them were in position 2 (8.5%). Medialized screws were considered those who had a positive response to stimulation of less than 6 mA. CONCLUSIONS: Electrical stimulation allowed a reduction of risk of medial positioning of thoracic screws, minimizing the use of intraoperative radiographs.

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.

Objectives: Lumbar spine surgery causes a muscular injury during its approach that could worsen long-term postoperative functional results. This study aims to analyze the postoperative paraspinal atrophy associated with two types of intervention., Material and Methods: Clinical records and lumbar magnetic resonance imaging were collected from a group of 41 patients, 20 underwent laminectomy with lumbar fixation due to lumbar spinal stenosis (fixation group) and another group of 21 underwent hemilaminectomy without fixation due to lumbar disc disease (non-fixation group). In which muscle atrophy was analyzed quantitatively., Results: We found a negative correlation between age and preoperative muscle, which was higher in those who underwent lumbar fixation (rho = -0.64 p = .002). We also found a positive correlation between preoperative muscle and postoperative atrophy (rho = 0.32 p = .041). In the age, sex and fixation adjusted multivariate linear regression model (R 2 = 0.31), laminectomy with fixation is attributed to 5.3% atrophy (IC95 1.4-9.5%, p = .017); preoperative musculature > 70% is attributed to atrophy of 13.8% (95% CI 5.5%-22%, p = .002). Age did not correlate with postoperative atrophy., Conclusions: Paraspinal muscle atrophy after lumbar spinal surgery is greater if an extensive approach is performed such as complete laminectomy with bilateral facetectomy and transpedicular fixation. A greater previous musculature regardless of age, sex and type of surgery also predicts greater postoperative atrophy., (Copyright © 2018 Sociedad Española de Neurocirugía. Publicado por Elsevier España, S.L.U. All rights reserved.)

Antecedentes: La escoliosis idiopática del adolescente se define como una deformidad tridimensional de la columna vertebral que se presenta entre los 10 y los 18 años, y que se manifiesta con una curvatura vertebral en el plano coronal mayor de 10°. Esta deformidad afecta al 2-3% de la población general, pero solo el 10% del total requerirá en algún momento tratamiento quirúrgico. El método de elección para el manejo es el uso de tornillos transpediculares y barras desrotadoras., Objetivo: Realizar un análisis descriptivo de los pacientes que recibieron manejo quirúrgico en nuestro instituto con tornillos transpediculares y barras., Método: Se trata de un estudio observacional, retrospectivo, analítico, abierto, de muestreo no probabilístico, en el que se incluyeron los pacientes tratados con manejo quirúrgico entre 2012 y 2013. Las deformidades se estratificaron de acuerdo con la clasificación de Lenke. El ángulo de corrección de la deformidad, los niveles instrumentados, el sangrado transquirúrgico y la presencia de complicaciones fueron las variables analizadas., Resultados: La mayoría de los pacientes presentaron curvas Lenke IBN, Nash Moe III, Cobb un promedio de 59.4° y cifosis de 47.8. En promedio se siguió a los pacientes por 35.84 meses, detectando un aumento de la curvatura coronal de 2.28° y un aumento de la curvatura sagital de 2.8°., Conclusión: Al comparar estos resultados y la literatura mundial se concluyó que el tratamiento de la escoliosis idiopática del adolescente es un método seguro y reproducible que ofrece una mayor ventaja biomecánica y biológica sobre el uso de instrumentación mixta utilizada anteriormente., Background: Adolescent’s idiopathic scoliosis is defined as a three-dimensional deformity of the spine, which occurs between 10 and 18-year-old, has a spinal curvature >10° in the coronal plane. This deformity affects 2–3% of the general population, however, only 10% of the total will require surgery at some point. The method of choice for management is the use of pedicle screws and rods derotational., Objective: To perform a descriptive analysis of patients who received surgical treatment in our institute with pedicle screws and rods., Methods: This is an observational, retrospective, analytical, open study, non-probability sampling, in which patients requiring surgical treatment at our institute between 2012 and 2013 were included, the deformities were stratified according to the classification of Lenke. The angle of deformity correction, instrumented levels, amount of bleeding, presence of complications were the variables analyzed., Results: Lenke classifying mostly IBN, Moe Nash III, an average of 59.4° Cobb and kyphosis of 47.8. On average it was followed patients for 35.84 months, detecting an increase 2.28° coronal curvature and sagittal curvature increase of 2.8°., Conclusion: Comparing these results and world literature concluded that the treatment of adolescent’s idiopathic scoliosis is a safe and reproducible method that provides greater biomechanical and biological advantage over the use of mixed instrumentation used previously., (Copyright: © 2018 Permanyer.)