Evaluación de la función pulmonar en escoliosis idiopática del adolescente manejado con instrumentación posterior con sistema de ganchos sublaminares / Pulmonary function assessment in juvenile idiopathic scoliosis managed with posterior instrumentation with a sublaminar hook system

Resumen: Introducción: La escoliosis es una deformidad de la columna vertebral; se diagnostica por el método de Cobb presentando una angulación mayor de 10o en proyección radiográfica anteroposterior. Produce alteraciones pulmonares de tipo restrictivo en angulaciones mayores a 50o. Su manejo puede ser quirúrgico, mejorando la angulación y el proceso restrictivo pulmonar. Se comparó la función pulmonar pre- y postquirúrgica con espirometría. Material y métodos: 27 pacientes, cirugía correctiva mediante instrumentación posterior con ganchos sublaminares, barras y artrodesis posterolateral. Ambos géneros. 11-15 años. Espirometría prequirúrgica y postquirúrgica a los seis meses. Fueron excluidos quienes carecían de espirometría postquirúrgica y/o aquéllos con evento infeccioso pulmonar postquirúrgico. Índice de Cobb, pre- y postquirúrgico. Espirometría: función pulmonar, la capacidad vital forzada (VCF) y el volumen espiratorio forzado en un segundo (FEV1). Estadística descriptiva, t Student. Resultados: Femenino 78% y masculino 22%, 13.7 ± 1.22 años. Método de Cobb 40 a 110o; prequirúrgico, 64.48 ± 17.79o y postquirúrgico, 30.44 ± 10.90o. No hubo valor de 0o. Capacidad pulmonar: prequirúrgico VCF para los valores de la curva de escoliosis (p < 0.0001) y significativa marginal para FEV1 (p = 0; inicial 40.6-122.0%, media 76.3 ± 18.8%; postquirúrgico 40.75-112.6%, media 76.5 ± 16.8%. FEV1 prequirúrgico 39.83-111.59%, media 73.9 ± 16.8%; post­quirúrgico 42.86-120.79%, media de 69.7 ± 16.5. Diferencia estadísticamente significativa 0.064). Conclusiones: El sistema de ganchos sublaminares en abordaje posterior ofrece mejoría de la curva de la escoliosis idiopática del adolescente evaluada por método de Cobb, detiene el progreso del deterioro de la función pulmonar, con mejoría significativa para el volumen espiratorio forzado en un segundo.

Abstract: Introduction: Scoliosis is a spine deformity diagnosed using Cobb's method when the AP X-ray view shows an angulation greater than 10o. Scoliosis exceeding 50o results in restrictive pulmonary alterations. Surgical management improves the angulation and the pulmonary restrictive process. The pre- and post-operative pulmonary function values were compared using spirometry. Material and methods: 27 patients of both genders, ages 11-15 years, underwent corrective surgery using posterior instrumentation with sublaminar hooks, rods and posterolateral arthrodesis. Spirometry was done preoperatively and six months after the surgery. Patients without a postoperative spirometry and/or a postoperative episode of pulmonary infection were excluded. The pre- and postoperative Cobb index was calculated. Spirometry: lung function at forced vital capacity (FVC) and forced expiratory volume in one second (FEV1). Descriptive statistics, Student t test. Results: Females, 78%; males, 22%; 13.7 ± 1.22 years. Cobb method 40 - 110o, preoperative angle 64.48 ± 17.79o and postoperative angle 30.44 ± 10.90º. There were no 0o values. Lung function: preoperative FVC for the values of the scoliosis curve (p < 0.0001) and significant marginal FEV1 (p = 0. Baseline: 40.6-122.0%, mean: 76.3 ± 18.8%, postoperative: 40.75-112.6%, mean: 76.5 ± 16.8%. Preoperative FEV1: 39.8-111.59%, mean: 73.9 ± 16.8%, postoperative: 42.86-120.79%, mean: 69.7 ± 16.5. The difference was statistically significant, 0.064). Conclusions: The sublaminar hook system with a posterior approach provides improvement of the idiopathic scoliosis curve of adolescents assessed with the Cobb method. It stops the progression of lung function impairment, with a significant improvement in forced expiratory volume in one second.

Partial baroreceptor dysfunction and low plasma nitric oxide bioavailability as determinants of salt-sensitive hypertension: a reverse translational rat study

This study determined whether clinical salt-sensitive hypertension (cSSHT) results from the interaction between partial arterial baroreceptor impairment and a high-sodium (HNa) diet. In three series (S-I, S-II, S-III), mean arterial pressure (MAP) of conscious male Wistar ChR003 rats was measured once before (pdMAP) and twice after either sham (SHM) or bilateral aortic denervation (AD), following 7 days on a low-sodium (LNa) diet (LNaMAP) and then 21 days on a HNa diet (HNaMAP). The roles of plasma nitric oxide bioavailability (pNOB), renal medullary superoxide anion production (RMSAP), and mRNA expression of NAD(P)H oxidase and superoxide dismutase were also assessed. In SHM (n=11) and AD (n=15) groups of S-I, LNaMAP-pdMAP was 10.5±2.1 vs 23±2.1 mmHg (P<0.001), and the salt-sensitivity index (SSi; HNaMAP−LNaMAP) was 6.0±1.9 vs 12.7±1.9 mmHg (P=0.03), respectively. In the SHM group, all rats were normotensive, and 36% were salt sensitive (SSi≥10 mmHg), whereas in the AD group ∼50% showed cSSHT. A 45% reduction in pNOB (P≤0.004) was observed in both groups in dietary transit. RMSAP increased in the AD group on both diets but more so on the HNa diet (S-II, P<0.03) than on the LNa diet (S-III, P<0.04). MAP modeling in rats without a renal hypertensive genotype indicated that the AD*HNa diet interaction (P=0.008) increases the likelihood of developing cSSHT. Translationally, these findings help to explain why subjects with clinical salt-sensitive normotension may transition to cSSHT.

An improved strategy for evaluating the extent of chronic arterial baroreceptor denervation in conscious rats

There is no index or criterion of aortic barodenervation, nor can we differentiate among rats that have suffered chronic sham, aortic or sino-aortic denervation. The objective of this study was to develop a procedure to generate at least one quantitative, reproducible and validated index that precisely evaluates the extent of chronic arterial barodenervation performed in conscious rats. Data from 79 conscious male Wistar rats of about 65-70 days of age with diverse extents of chronic arterial barodenervation and used in previous experiments were reanalyzed. The mean arterial pressure (MAP) and the heart rate (HR) of all rats were measured systematically before (over 1 h) and after three consecutive iv bolus injections of phenylephrine (PHE) and sodium nitroprusside (SNP). Four expressions of the effectiveness of barodenervation (MAP lability, PHE ratio, SNP ratio, and SNP-PHE slope) were assessed with linear fixed models, three-level average variance, average separation among levels, outlier box plot analysis, and overlapping graphic analysis. The analysis indicated that a) neither MAP lability nor SNP-PHE slope was affected by the level of chronic sodium intake; b) even though the Box-Cox transformations of both MAP lability [transformed lability index (TLI)] and SNP-PHE slope [transformed general sensitivity index (TGSI), {((3-(ΔHRSNP-ΔHRPHE/ΔMAPSNP-ΔMAPPHE))-0.4-1)/-0.04597}] could be two promising indexes, TGSI proved to be the best index; c) TLI and TGSI were not freely interchangeable indexes for this purpose. TGSI ranges that permit differentiation between sham (10.09 to 11.46), aortic (8.40 to 9.94) and sino-aortic (7.68 to 8.24) barodenervated conscious rats were defined.