Pull-out strength of cemented solid versus fenestrated pedicle screws in osteoporotic vertebrae.

OBJECTIVES: Cement augmentation of pedicle screws could be used to improve screw stability, especially in osteoporotic vertebrae. However, little is known concerning the influence of different screw types and amount of cement applied. Therefore, the aim of this biomechanical in vitro study was to evaluate the effect of cement augmentation on the screw pull-out force in osteoporotic vertebrae, comparing different pedicle screws (solid and fenestrated) and cement volumes (0 mL, 1 mL or 3 mL). MATERIALS AND METHODS: A total of 54 osteoporotic human cadaver thoracic and lumbar vertebrae were instrumented with pedicle screws (uncemented, solid cemented or fenestrated cemented) and augmented with high-viscosity PMMA cement (0 mL, 1 mL or 3 mL). The insertion torque and bone mineral density were determined. Radiographs and CT scans were undertaken to evaluate cement distribution and cement leakage. Pull-out testing was performed with a material testing machine to measure failure load and stiffness. The paired t-test was used to compare the two screws within each vertebra. RESULTS: Mean failure load was significantly greater for fenestrated cemented screws (+622 N; p ⩽ 0.001) and solid cemented screws (+460 N; p ⩽ 0.001) than for uncemented screws. There was no significant difference between the solid and fenestrated cemented screws (p = 0.5). In the lower thoracic vertebrae, 1 mL cement was enough to significantly increase failure load, while 3 mL led to further significant improvement in the upper thoracic, lower thoracic and lumbar regions. CONCLUSION: Conventional, solid pedicle screws augmented with high-viscosity cement provided comparable screw stability in pull-out testing to that of sophisticated and more expensive fenestrated screws. In terms of cement volume, we recommend the use of at least 1 mL in the thoracic and 3 mL in the lumbar spine.Cite this article: C. I. Leichtle, A. Lorenz, S. Rothstock, J. Happel, F. Walter, T. Shiozawa, U. G. Leichtle. Pull-out strength of cemented solid versus fenestrated pedicle screws in osteoporotic vertebrae. Bone Joint Res 2016;5:419-426.

Validity and reliability of an adapted german version of scoliosis research society-22 questionnaire.

STUDY DESIGN: Study to determine the internal consistency and validity of adapted German version of Scoliosis Research Society-22 (SRS-22) questionnaire. OBJECTIVE: To evaluate the validity and reliability of adapted German version of SRS-22 questionnaire. SUMMARY OF BACKGROUND DATA: The SRS-22 questionnaire was developed to assess the health-related quality of life for English-speaking patients with idiopathic scoliosis. For scientific purpose and standardized comparison of outcome studies for the treatment of idiopathic scoliosis its adaptation into German is necessary to respect cultural and lingual differences. METHODS: Translation/retranslation of the English version of the SRS-22 was conducted, and all steps for cross-cultural adaptation process were performed. Thus, SRS-22 questionnaire and previously validated Roland-Morris score were mailed to 222 patients who had been treated surgically or conservatively for idiopathic scoliosis. Seventy-eight patients (35%) responded to the first set of questionnaires and 54 of the first time responder returned their second survey. The median age of all patients who joined the study was 19 years. Measures of reliability namely, selectivity, internal consistency, and reproducibility were determined by Cronbach's alpha statistics and intraclass correlation coefficient, respectively. Concurrent validity was measured by comparing with an already validated questionnaire (Roland-Morris score). Measurement was made using the Spearman correlation coefficient. RESULTS: The study demonstrated satisfactory internal consistency with high Cronbach's alpha values for 4 of the corresponding domains (pain, 0.75; self-image, 0.84; mental health, 0.88; and satisfaction, 0.61). However, the Cronbach's alpha value for function/activity domain (0.67) was considerably lower than the original English questionnaire. For the same domains intraclass correlation coefficient demonstrating satisfactory test/retest reproducibility. CONCLUSION: The adapted German version of the SRS-22 questionnaire can be used to assess the outcome of treatment for German-speaking patients with idiopathic scoliosis.

[Reproducibility of readings of ISO C 3D and CT lumbar pedicle screw scans]. / Reproduzierbarkeit der Befundung von lumbalen Pedikelschraubenpositionen mit ISO C 3D und CT.

PURPOSE: This study was conducted to evaluate the reproducibility of the reading of lumbar pedicle screw scans using a C-arm-based imaging system in comparison to computed tomography. The influence of the technique and the experience of the rater should be determined. MATERIALS AND METHODS: The lumbar spines of 23 patients were stabilized using 102 pedicle screws. The position of the screws was controlled intraoperatively using an Arcadis Orbic 3D scanner. All scans were evaluated independently by three raters. The position of the implants in reference to the pedicle walls was described. Additionally, another 100 lumbar pedicle screws in 16 patients were evaluated postoperatively with a multirow CT. Kappa according to Fleiss was calculated for the reproducibility of the rater statements. Each rater repeated the analysis of 24 screws to assess the intraobserver variance. RESULTS: The reports of the CT scans showed significantly less variation. The consent of all 3 raters was achieved in 79.4 vs. 65.1 % of cases. The Kappa values were 0.56 and 0.29, respectively. Poor results were obtained especially for the medial pedicle wall (consent 70.0 vs. 50.0 %). The influence of the experience of the rater was not able to be verified. CONCLUSION: The image quality of the ISO C 3D is worse than that of multirow CT scans for the evaluation of lumbar pedicle screws. This causes greater variance among the rater reports. We stopped using the ISO C 3D technique intraoperatively for the implantation of lumbar pedicle screws.

Peri-prosthetic bone density after implantation of a custom-made femoral component. A five-year follow-up.

Peri-prosthetic bone loss caused by stress shielding may be associated with aseptic loosening of femoral components. In order to increase primary stability and to reduce stress shielding, a three-dimensional, cementless individual femoral (Evolution K) component was manufactured using pre-operative CT scans. Using dual energy x-ray absorptiometry, peri-prosthetic bone density was measured in 43 patients, three months, six months, 3.6 and 4.6 years after surgery. At final follow-up there was a significant reduction in mean bone density in the proximal Gruen zones of -30.3% (zone 7) and -22.8% (zone 1). The density in the other zones declined by a mean of between -4% and -16%. We conclude that the manufacture of a three-dimensional, custom-made femoral component could not prevent a reduction in peri-prosthetic bone density.

Multiple skeletal metastases from a giant cell tumour of the distal fibula with fatal outcome.

A giant cell tumour is a primary lesion of bone of intermediate severity. Its histogenesis is unclear. In a few cases pulmonary metastases have been described. Multiple skeletal metastases in the absence of sarcomatous change have been observed. We present a case report of a 25-year-old woman with a recurrent giant cell tumour of the distal fibula. After a second recurrence and six years after the initial diagnosis, she rapidly developed multiple bony metastases. The outcome was fatal.

[Structure of human resources in a public hospital in Chile: an experience in introducing changes]. / Estructura y recursos humanos en un hospital público chileno: una experiencia de cambio.

This article discusses the structural and operational reform process that took place beginning in 1994 in Luis Calvo Mackenna Hospital, a tertiary pediatric care facility run by Oriente Metropolitan Health Center in Santiago, Chile. The formation of the Chilean health care system is briefly outlined, along with the changes brought about by the military government in 1979 and other transformations introduced by the first democratic government in 1990 and by the second one, in 1994. In spite of Chile's favorable health indicators and of the current government's desire to establish equitable services and to launch a decentralized system, the health care system that was fundamentally modeled in the fifties and sixties has failed to respond successfully to the demographic transition and to the population's new epidemiologic profile. One of the main problems is that services at the secondary and tertiary levels lack what is necessary to respond to the demand. Under a new leadership with an interest in modern administrative methods, clinical services at Luis Calvo Mackenna Hospital were restructured with new departments and units, a study of the organizational climate was carried out, the entire staff was intensively trained so as to generate a spirit of involvement and a new vision of the hospital's mission and teamwork, and a strategic plan was drawn up that is still being implemented.