Distal junctional kyphosis in patients with Scheuermann’s disease: a retrospective radiographic analysis

Purpose To investigate the relationship between preoperative and postoperative spinopelvic alignment and occurrence of DJK/DJF. Study design/setting This was a retrospective observational cohort study. Patient sample The sample included 40 patients who underwent posterior correction of SK from January 2006 to December 2014. Outcome measures Correlation analysis between the preoperative and postoperative spinopelvic alignment parameters and development of DJK over the course of the study period were studied. Methods Whole spine X-rays obtained before surgery, 3 months after surgery and at the latest follow-up were analyzed. The following parameters were measured: maximum of thoracic kyphosis (TK), lumbar lordosis (LL), sagittal vertical axis (SVA), pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), lower instrumented vertebra (LIV) and LIV plumb line. Development of DJK was considered as the primary end point of the study. The patient population was split into a control and DJK group, with 34 patients and 6 patients, respectively. Statistic analysis was performed using unpaired t test for normal contribution and Mann–Whitney test for skew distributed values. The significance level was set to 0.05. Results DJK occurred in 15% (n = 6) over the study period. There was a significantly lower postoperative TK for the group with DJK (42.4 ± 5.3 vs 49.8 ± 6.7, p = 0.015). LIV plumb line showed higher negative values in the DJK group (−43.6 ± 25.1 vs −2.2 ± 17.8, p = 0.0435). Furthermore, postoperative LL changes were lower for the DJK group (33.84 ± 13.86% vs 31.77 ± 14.05, p < 0.0001.) The age of the patients who developed DJK was also significantly lower than that of the control group (16.8 ± 1.7 vs 19.6 ± 4.9, p = 0.0024.) Conclusions SK patients who developed DJK appeared to have a significantly higher degree of TK correction and more negative LIV plumb line. In addition, there may be a higher risk for DJK in patients undergoing corrective surgery at a younger age

A novel delta current method for transport stoichiometry estimation

BACKGROUND: The ion transport stoichiometry (q) of electrogenic transporters is an important determinant of their function. q can be determined by the reversal potential (E(rev)) if the transporter under study is the only electrogenic transport mechanism or a specific inhibitor is available. An alternative approach is to calculate delta reversal potential (ΔE(rev)) by altering the concentrations of the transported substrates. This approach is based on the hypothesis that the contributions of other channels and transporters on the membrane to E(rev) are additive. However, E(rev) is a complicated function of the sum of different conductances rather than being additive. RESULTS: We propose a new delta current (ΔI) method based on a simplified model for electrogenic secondary active transport by Heinz (Electrical Potentials in Biological Membrane Transport, 1981). ΔI is the difference between two currents obtained from altering the external concentration of a transported substrate thereby eliminating other currents without the need for a specific inhibitor. q is determined by the ratio of ΔI at two different membrane voltages (V(1) and V(2)) where q = 2RT/(F(V(2) –V(1)))ln(ΔI(2)/ΔI(1)) + 1. We tested this ΔI methodology in HEK-293 cells expressing the elctrogenic SLC4 sodium bicarbonate cotransporters NBCe2-C and NBCe1-A, the results were consistent with those obtained with the E(rev) inhibitor method. Furthermore, using computational simulations, we compared the estimates of q with the ΔE(rev) and ΔI methods. The results showed that the ΔE(rev) method introduces significant error when other channels or electrogenic transporters are present on the membrane and that the ΔI equation accurately calculates the stoichiometric ratio. CONCLUSIONS: We developed a ΔI method for estimating transport stoichiometry of electrogenic transporters based on the Heinz model. This model reduces to the conventional reversal potential method when the transporter under study is the only electrogenic transport process in the membrane. When there are other electrogenic transport pathways, ΔI method eliminates their contribution in estimating q. Computational simulations demonstrated that the ΔE(rev) method introduces significant error when other channels or electrogenic transporters are present and that the ΔI equation accurately calculates the stoichiometric ratio. This new ΔI method can be readily extended to the analysis of other electrogenic transporters in other tissues

Resultados de una encuesta sobre tratamiento de la cifosis torácica causada por enfermedad de Scheuermann Resultados de uma pesquisa sobre o tratamento da cifose torácica de Scheuermann Results of a survey on the treatment of thoracic Scheuermann´s kyphosis

OBJETIVO: Conocer que parámetros se deben considerar para encarar el tratamiento de la cifosis torácica causada por la enfermedad de Scheuermann. MÉTODO: Se realizó una recolección de informaciones consistente en aplicar un cuestionario a 25 informantes calificados, colegas de diferentes países de Íbero/Latinoamérica miembros de SILACO (Sociedad Íbero/Latinoamericana de Columna) y se analizaron los resultados de las mismas. RESULTADOS: Como tratamiento ortopédico, la mayoría se inclinó por el uso del corsé de Milwaukee, indicado en pacientes prepúberes y pospúberes con curvas mayores de 60º y en curvas de menos de 60º si tienen dolor. El tiempo de uso: 22 hrs por día, su mantenimiento hasta llegar a Risser 4 o 5. Se observó una tasa de abandono de 48% al plan terapéutico. En lo referente a tratamiento quirúrgico, las indicaciones surgen: por localización de la deformidad, el valor angular, dolor, edad y estética. La extensión del área a fusionar fue determinada con los espinogramas y radiografías dinámicas. Se eligió la vía posterior como vía de abordaje con barras y tornillos, y en algunos casos la combinación con ganchos. Se evaluaron los resultados del tratamiento quirúrgico (de acuerdo a la opinión del médico), que fueron catalogados como buenos en un 64%. CONCLUSIONES: Se realizó una encuesta de opinión sobre el tratamiento de la cifosis torácica causada por enfermedad de Scheuermann .y se analizaron 25 formularios de respuestas de calificados cirujanos de columna, de diferentes países de Ibero/Latinoamérica miembros de SILACO. La encuesta ha permitido establecer normas de conducta terapéuticas (ortopédicas y quirúrgicas) para el tratamiento de esta afección.<br>OBJETIVO: Obter os parâmetros a serem considerados para realizar o tratamento da cifose torácica de Scheuermann. MÉTODOS: Os dados foram obtidos por meio de um questionário que foi respondido por 25 membros da SILACO (Sociedad Ibero-Latino-americana de Columna) e análise dos resultados das respostas. RESULTADOS: Como tratamento ortopédico, a maioria optou pelo uso do colete de Milwaukee indicado para pacientes pré-púberes e pós-púberes com curvas maiores que 60° e curvas de menos de 60° acompanhadas de dor. O tempo de uso diário do colete foi de 22 horas até atingir Risser 4 ou 5. A taxa de abandono do plano terapêutico foi de 48%. Em relação ao tratamento cirúrgico, a maioria afirmou que as indicações estão relacionadas com localização da deformidade, valor angular, dor, idade e a estética. A extensão da área da artrodese foi determinada por meio de radiografias totais de coluna e dinâmicas. A abordagem posterior foi escolhida como a via de acesso preferida, utilizando-se hastes, parafusos e associação com ganchos. CONCLUSÃO: Realizamos uma pesquisa sobre o tratamento da cifose torácica decorrente de doença Scheuermann. Analisamos 25 formulários de resposta de cirurgiões de coluna qualificados de diferentes países membros da SILACO. A pesquisa permitiu estabelecer normas de conduta terapêutica (ortopédicas e cirúrgicas) para tratamento dessa afecção.<br>OBJECTIVE: To determine which parameters should be considered to address the treatment of thoracic Scheuermann kyphosis. METHOD: A survey information with a questionnaire applied to 25 informants, colleagues from different countries of Ibero-Latin American members of SILACO (Sociedad Ibero-Latinoamericana de Columna) and to analyze the results. RESULTS: Regarding to the orthopedic treatment the majority tended towards the use of Milwaukee brace for pre-pubertal and post-pubertal patients with curves greater than 60º and in curves of less than 60º if they had pain. Time of use: Twenty two hours per day until reaching Risser of 4 or 5. The rejection rate of the therapeutic plan was 48%. Regarding surgical treatment, the majority established that the indications are related to the location of the deformity, the angular value, pain, age and aesthetics. The extension of the area to be fused was determined by the total column and dynamic X-rays. Posterior approach was chosen to access; rod and screws, and in some cases the combination with hooks. CONCLUSION: We conducted a survey about the treatment of thoracic kyphosis due to Scheuermann disease and analyzed 25 response forms of qualified spine surgeons from different countries that are SILACO members. The survey has allowed to establish standards of management (orthopedic and surgical) for the treatment of this condition