Resumen: Antecedentes: Mediante un meta-análisis de tres niveles, el objetivo de esta investigación fue examinar la relación entre la participación de los padres en los deberes escolares y el rendimiento académico de los estudiantes, así como estudiar el rol mediador en esta relación de ciertas variables que podrían haber estado relacionadas con algunos resultados inconsistentes en estudios primarios. Método: Se identificaron 28 estudios, con 252 tamaños del efecto, para un total de 378222 participantes. Resultados: Los resultados revelaron una débil relación negativa entre la implicación de los padres en los deberes y el rendimiento de los estudiantes (r = −0,064, p < 0,001). Esta relación fue moderada por el tipo de implicación parental. Específicamente, el rendimiento de los estudiantes se relacionó positivamente con el apoyo a la autonomía, pero no con el apoyo al contenido, el control de los padres, la frecuencia y la combinación de estas dimensiones. Además, dicha relación fue moderada por la medida de rendimiento, el curso de los estudiantes y el género de los padres. Conclusiones: Es necesaria más investigación cualitativa sobre lo que ocurre en torno a las interacciones entre padres e hijos a la hora de la realización de los deberes escolares.

Abstract: Background: Applying a three-level meta-analysis, the goal of our investigation was to examine the relationship between parental homework involvement and students' achievement, and to investigate whether certain study features could have resulted in the inconsistent results relating to this relationship from prior studies. Method: We identified a total of 28 studies (32 independent samples) with 252 effect sizes for a total of 378222 participants. Results: Our meta-analysis revealed an overall weak negative relationship between parental homework involvement and students' achievement (r = −0.064, p < .001). The overall relationship was moderated by the dimension of parental homework involvement. Specifically, students' achievement was positively related to autonomy support, but largely unrelated to content support, parental control, frequency, and mixed. Additionally, the overall relationship was moderated by achievement measure, grade level, and parent gender. Conclusions: Given that parental autonomy support was the only dimension that was positively related to students' achievement, it would be important to conduct qualitative research that provides longitudinal descriptions of parent-child interactions relating to homework tasks as children make their transition from elementary to middle and high school.

Resumen: Antecedentes: El principal objetivo de la investigación ha sido (1) identificar diferentes perfiles de estudiantes a partir de tres de sus propósitos para realizar deberes (académico, auto-regulación y de búsqueda de aprobación) y (2) analizar su relación con el esfuerzo dedicado a la realización de los deberes, la cantidad de deberes finalizados y el rendimiento en matemáticas. Método: El estudio involucró a 3018 estudiantes de octavo grado de diferentes áreas geográficas de China. Los datos se analizaron mediante Análisis de Perfiles latentes (LPA). Resultados: Se identificaron cuatro perfiles diferentes: alto en los tres propósitos (13.39%), moderado en los tres propósitos (56.63%), bajo en los tres propósitos (26.04%) y muy bajo en los tres propósitos (3,94%). Pertenecer a un determinado perfil se relaciona significativa y positivamente con el esfuerzo dedicado a los deberes, la cantidad de deberes finalizados y con el rendimiento en matemáticas. Conclusiones: La pertenencia a uno u otro perfil puede tener diferentes consecuencias o implicaciones tanto para el comportamiento del alumno (por ejemplo, en cuanto a su implicación en la realización de los deberes y respecto del rendimiento académico) como para la práctica educativa de los profesores y las familias.

Abstract: Background: The main objective of the research was (1) to identify different profiles of students based on three purposes they had for homework (academic, self-regulatory and approval-seeking) and (2) to analyze their relationship with the homework effort, completion, and math achievement. Method: The study involved 3,018 eighth-grade students from various areas in China. Data were analyzed with Mplus using Latent Profile Analysis (LPA). Results: As hypothesized, four different profiles were identified: High Profile (high in all purposes; 13,39%), Moderate Profile (moderate in all purposes; 56.63%), Low Profile (low in all purposes; 26,04%), and Very Low Profile (very low in all purposes; 3.94%). Belonging to a certain profile was related to the homework effort, completion, and math achievement: the higher the purposes, the greater the homework effort, completion, and higher math performance. Conclusions: The results of our study suggest certain similarities and consistency between individual groups (similar profiles) at different ages (i.e., eighth and eleventh graders). Belonging to one or the other profile may have different consequences or implications both for the student's behavior (for example, in terms of their involvement in homework and academic achievement) and for the educational practice of teachers and families.

OBJECTIVES: To evaluate the safety and efficacy of a novel bone cement-injectable cannulated pedicle screw augmented with polymethylmethacrylate in osteoporotic spinal surgery. METHODS: This study included 128 patients with osteoporosis (BMD T-score −3.2±1.9; range, −5.4 to -2.5) who underwent spinal decompression and instrumentation with a polymethylmethacrylate-augmented bone cement-injectable cannulated pedicle screw. Postoperative Visual Analogue Scale scores and the Oswestry Disability Index were compared with preoperative values. Postoperative plain radiographs and computed tomography (CT) scans were performed immediately after surgery; at 1, 3, 6, and 12 months; and annually thereafter. RESULTS: The mean follow-up time was 42.4±13.4 months (range, 23 to 71 months). A total of 418 polymethylmethacrylate-augmented bone cement-injectable cannulated pedicle screws were used. Cement extravasations were detected in 27 bone cement-injectable cannulated pedicle screws (6.46%), mainly in cases of vertebral fracture, without any clinical sequela. The postoperative low back and lower limb Visual Analogue Scale scores were significantly reduced compared with the preoperative scores (<0.01), and similar results were noted for the Oswestry Disability Index score (p<0.01). No significant screw migration was noted at the final follow-up relative to immediately after surgery (p<0.01). All cases achieved successful bone fusion, and no case required revision. No infection or blood clots occurred after surgery. CONCLUSIONS: The polymethylmethacrylate-augmented bone cement-injectable cannulated pedicle screw is safe and effective for use in osteoporotic patients who require spinal instrumentation.

OBJECTIVES: To describe a new approach for the application of polymethylmethacrylate augmentation of bone cement-injectable cannulated pedicle screws. METHODS: Between June 2010 and February 2013, 43 patients with degenerative spinal disease and osteoporosis (T-score <-2.5) underwent lumbar fusion using cement-injectable cannulated pedicle screws. Clinical outcomes were evaluated using a Visual Analog Scale and the Oswestry Disability Index. Patients were given radiographic follow-up examinations after 3, 6, and 12 months and once per year thereafter. RESULTS: All patients were followed for a mean of 15.7±5.6 months (range, 6 to 35 months). The Visual Analog Scale and Oswestry Disability Index scores showed a significant reduction in back pain (p = 0.018) and an improvement in lower extremity function (p = 0.025) in patients who underwent lumbar fusion using the novel screw. Intraoperative cement leakage occurred in four patients, but no neurological complications were observed. Radiological observation indicated no loosening or pulling out of the novel screw, and bone fusion was excellent. CONCLUSIONS: The described polymethylmethacrylate augmentation technique using bone cement-injectable cannulated pedicle screws can reduce pain and improve spinal dysfunction in osteoporotic patients undergoing osteoporotic spine surgery.

OBJECTIVES: To explore the microendoscopic discectomy technique and inclusion criteria for the treatment of recurrent lumbar disc herniation and to supply feasible criteria and technical notes to avoid complications and to increase the therapeutic effect. METHODS: A consecutive series of 25 patients who underwent posterior microendoscopic discectomy for recurrent lumbar disc herniation were included. The inclusion criteria were as follows: no severe pain in the lumbar region, no lumbar instability observed by flexion-extension radiography and no intervertebral discitis or endplate damage observed by magnetic resonance imaging. All patients were diagnosed by clinical manifestations and imaging examinations. RESULTS: Follow-up visits were carried out in all cases. Complications, such as nerve injuries, were not observed. The follow-up outcomes were graded using the MacNab criteria. A grade of excellent was given to 12 patients, good to 12 patients and fair to 1 patient. A grade of excellent or good occurred in 96% of cases. One patient relapsed 3 months after surgery and then underwent lumbar interbody fusion and inner fixation. The numerical rating scale of preoperative leg pain was 7.4± 1.5, whereas it decreased to 2.1±0.8 at 7 days after surgery. The preoperative Oswestry disability index of lumbar function was 57.5±10.0, whereas it was 26.0±8.5 at 7 days after surgery. CONCLUSION: In these cases, microendoscopic discectomy was able to achieve satisfactory clinical results. Furthermore, it has advantages over other methods because of its smaller incision, reduced bleeding and more efficient recovery.

OBJECTIVE: AO/OTA 31-A3 intertrochanteric femoral fractures have completely different fracture line directions and biomechanical characteristics compared with other types of intertrochanteric fractures. The choice of the fixation method has been a focus of dispute among orthopedic trauma surgeons. The purpose of this study was to review the outcomes of these fractures treated with a percutaneous compression plate at our institute. METHOD: Seventeen patients with AO/OTA 31-A3 intertrochanteric femoral fractures were treated with a percutaneous compression plate at our institute from January 2010 to December 2011. The clinical data and imaging results were retrospectively analyzed. RESULTS: The medical complication of popliteal vein thrombosis occurred in one patient. Sixteen patients were followed up for 12 to 21 months. Two patients had malunion and mild pain. Fracture collapse occurred in two patients, with one having head penetration. These two patients had moderate pain. There were no occurrences of nonunion or reoperation. The mean Harris hip score obtained during the last follow-up was 84.1 (61-97). Patients with a poor quality of reduction were more likely to have pain results (p = 0.001). A trend existed toward the presence of a poor quality of reduction (p = 0.05) in patients with a collapse of fracture. Patients with poor preoperative mobility were more likely to have a lower Harris hip score (p = 0.000). CONCLUSION: The percutaneous compression plate is an alternative device for the treatment of AO/OTA 31-A3 intertrochanteric femoral fractures. Good fracture reduction and an ideal placement position of the neck screw are important in the success of the device.