Knee extensor muscular activity estimation during different walking patterns: flat normal and brisk walking, stair climbing.

Preserving mobility, the ability to keep a correct posture and dynamic balance in order to walk properly, is fundamental to maintain autonomy in daily life. Based on the correlation between muscle groups and autonomy, previous research has suggested that maintaining muscular tone in knee extensors is critical. Continuous training of knee extensors during aging is therefore essential to maintain independence. In this work, it is hypothesized that it is possible to estimate knee extensor activity only from IMU data based on a simple lower limbs model. The accuracy of the knee extensor activity estimation algorithm has been tested using sEMG measurements as control data on three different walking patterns: normal walk, fast walk and stair climbing. Estimated knee torque area and measured muscular activity for each step were compared confirming a high estimation accuracy with a correlation efficient R=0.80. Moreover, muscular activity can be divided based on intensity in three groups of statistically significant difference confirmed by the Steel-Dwass method. Future works should test the usability of the algorithm for different walking patterns, and use the collected data and the refined algorithm to implement a smart resistive device to increase knee extensor exertion during each walking pattern to the level necessary for sufficient extensor training.

Degenerative facet joint changes in lumbar percutaneous pedicle screw fixation without fusion.

BACKGROUND: Aim of the study was to evaluate degenerative lumbar facet-joints changes after percutaneous pedicle screw fixation (PPSF) in the treatment of lumbar fractures. MATERIALS AND METHODS: Thirty patients underwent short PPSF without fusion. CT-scan was performed in the pre- and post-operative time at four, eight and 12 months. The six zygapophyseal joints adjacent the fracture's level were evaluated. RESULTS: At four months patients showed no differences between pre- and post-operative joint radiographic aspect. At eight and 12 months, CT-scan demonstrated a progressive degeneration only in the middle joints respectively in 21.42% and in 76.92% of the cases. All 10 disrupted facet joints showed progressive degenerative changes at eight and 12 months. CONCLUSION: Lumbar percutaneous fixation without fusion induces little degenerations essentially collocated in the middle joints close to fracture level at eight and 12 months. In the proximal and distal joints adjacent the screws degenerative changes can be seen only when associated to pedicle-screw encroachment.

Angular sway propagation in One Leg Stance and quiet stance with Inertial Measurement Units for older adults.

Postural stability degrades with age, threating the health and life quality of the older adults. One Leg Stance (OLS) is one of the standard and commonly adopted assessments for postural stability, and the postural sway in OLS has been demonstrated to be related with age. The propagation of postural sway between body segments could be a hint to the underlying mechanism of balance control. However, it is not yet fully understood. Therefore, the aim of this paper was to study the angular sways and their propagation of the head, trunk, and lower limb in healthy older adults. A cross-correlation of the normalized angular speeds was performed and the experiment with 68 older adults was conducted. The results showed that the head, hip and ankle joints affected the transfer of angular sway with a relatively lower correlation and longer latency.

The impact of sagittal balance on low back pain in patients treated with zygoapophysial facet joint injection.

INTRODUCTION: Aim of the study was to evaluate the effectiveness of facet joints injections in lumbar facet syndrome correlating clinical results to the sagittal contour of the spine. METHODS: Facet joints degree degeneration was evaluated using MRI according to Fujiwara classification. Sagittal contour of the spine was evaluated according to Roussouly classification. The clinical results were evaluated with visual analog scale (VAS) at regular intervals. RESULTS: Twenty-eight (70 %) of the 40 patients had clinical symptoms improvement, 12 (30 %) showed no benefit. There was a statistical significant correlation between postoperative VAS value improvement and Roussouly spine type 1 and 3 (p = 0.003). The benefit was more durable in patients with grade 2 or 3 degeneration. CONCLUSIONS: Facet joints injections have a more effective diagnostic than therapeutic value. The procedure could, however, give a temporary pain relief in cases with an overload of the facet joints due to lumbar hyperlordosis.

Posterior percutaneous reduction and fixation of thoraco-lumbar burst fractures.

BACKGROUND: Treatment of A3 thoraco-lumbar and lumbar spinal fractures nowadays remains a controversial issue. Percutaneous techniques are becoming very popular in the last few years to reduce the approach-related morbidity associated with conventional techniques. HYPOTHESIS: Purpose of the study was to analyze the clinical and radiological outcome of patients who underwent percutaneous posterior fixation without fusion for the treatment of thoraco-lumbar and lumbar A3 fractures. MATERIALS AND METHODS: Sixty-three patients, having sustained a single-level thoraco-lumbar fracture, underwent short segment percutaneous instrumentation and were retrospectively analyzed. sagittal index (SI) was calculated in all patients. Clinical and functional outcome were evaluated by Visual Analog Scale (VAS), Oswestry Disability Index (ODI) and Short Form General Health Status (SF-36). RESULTS: Average operative blood loss was 82 mL (50-320). Mean pre-operative SI in the thoraco-lumbar segment was 13.3° decreased to 5.8° in the immediate postoperative with a mean deformity correction of 7.5. Mean pre-operative SI in the lumbar segment was 16.5° decreased to 11.3° in the immediate postoperative with a mean deformity correction of 5.2. Not statistically significant correction loss was registered at 1-year minimum follow-up. Constant clinical conditions improvement in the examined patients was observed. CONCLUSION: Percutaneous pedicle screw fixation for A3 thoraco-lumbar and lumbar spinal fractures is a reliable and safe procedure. LEVEL OF EVIDENCE: Level IV. Retrospective study.

Development of new muscle contraction sensor to replace sEMG for using in muscles analysis fields.

Nowadays, the technologies for detecting, processing and interpreting bioelectrical signals have improved tremendously. In particular, surface electromyography (sEMG) has gained momentum in a wide range of applications in various fields. However, sEMG sensing has several shortcomings, the most important being: measurements are heavily sensible to individual differences, sensors are difficult to position and very expensive. In this paper, the authors will present an innovative muscle contraction sensing device (MC sensor), aiming to replace sEMG sensing in the field of muscle movement analysis. Compared with sEMG, this sensor is easier to position, setup and use, less dependent from individual differences, and less expensive. Preliminary experiments, described in this paper, confirm that MC sensing is suitable for muscle contraction analysis, and compare the results of sEMG and MC sensor for the measurement of forearm muscle contraction.

Application of wireless inertial measurement units and EMG sensors for studying deglutition - Preliminary results.

Different types of sensors are being used to study deglutition and mastication. These often suffer from problems related to portability, cost, reliability, comfort etc. that make it difficult to use for long term studies. An inertial measurement based sensor seems a good fit in this application; however its use has not been explored much for the specific application of deglutition research. In this paper, we present a system comprised of an IMU and EMG sensor that are integrated together as a single system. With a preliminary experiment, we determine that the system can be used for measuring the head-neck posture during swallowing in addition to other parameters during the swallowing phase. The EMG sensor may not always be a reliable source of physiological data especially for small clustered muscles like the ones responsible for swallowing. In this case, we explore the possibility of using gyroscopic data for the recognition of deglutition events.

Use of an ultra-miniaturized IMU-based motion capture system for objective evaluation and assessment of walking skills.

The increasing age of the world population is posing new challenges to our society, such as how to keep this aging population healthy and active despite of the age. In recent years, there has been a lot of interest for gait analysis for rehabilitation purposes as well as for performance assessment of this aging population. While current systems work well, they still have several limitations. Cost, need for specialized personnel, need to be used in a research center, and sporadic measurement prevent these systems from being widely used. The authors propose the use of extremely miniaturized, portable measurement systems, which can be worn by the users during their everyday life, and can monitor their gait over a long timespan. This paper presents the preliminary experiments with such a system.

Biomechanical evaluation of the phases during simulated endotracheal intubation (ETI): pilot study on the effect of different laryngoscopes.

Endotracheal Intubation (ETI) is a common airway procedure used to connect the larynx and the lungs through a windpipe in patients under emergency situations. The process is carried out by a laryngoscope inserted into the mouth, used to help doctors in visualizing the glottis and inserting the tube. Currently, very few studies on objective evaluation of the biomechanics of the doctors during the procedure have been done. Additionally, these studies have been concentrated only on the overall performance analysis, without any segmentation, with a consequent loss of important information. In this paper, the authors present a preliminary study on a methodology to objectively evaluate and segment the biomechanical performance of doctors during the ETI, using surface electromyography and inertial measurement units. In particular, the validation has been performed by comparing three kinds of laryngoscopes involving an expert doctor. Finally, results are presented and commented.

Cervical myelopathy due to ossification of the transverse atlantal ligament: a Caucasian case report operated on and literature analysis.

One case of cervical myelopathy associated to ossification of transverse atlantal ligament (OTAL) and C1 posterior arch hypoplasia in a Caucasian adult female is reported. A 53-year-old female affected by cervical myelopathy was treated with C1 laminectomy and posterior arthrodesis. CT scan demonstrated that the distance between ossification of the ligament and anterior cortex of the posterior arch of atlas was 6,2mm leading to consistent space reduction for spinal cord at this level. Patient underwent spinal cord decompression and fixation with C1 poliaxial screws in lateral masses and two bilateral crossing C2 laminar screws with an improvement of neurological functions at 4-years follow-up. The association between OTAL and C1 hypoplasia was reported in very few cases. The treatment with C1 laminectomy without fusion is reported in medical literature with good clinical outcome. Our patient obtained a neurological improvement at midterm follow-up with spinal cord decompression and fusion.

Transdiscal L5-S1 screws for the treatment of adult spondylolisthesis.

PURPOSE: The aim of the study was to evaluate clinical and radiographic outcome of patients treated with a modified Grob technique analysing the advantages related to increased mechanical stability. METHODS: 30 patients that underwent "in situ" fusion for L5-S1 spondylolisthesis were evaluated. All patients presented a low-dysplastic developmental L5-S1 spondylolisthesis. Patients were divided into two groups: A, in which L5-S1 pedicle instrumentation associated with transsacral screw fixation was performed, and B, in which L5-S1 pedicle instrumentation associated with a posterolateral interbody fusion (PLIF) was performed. RESULTS: Patients treated with transdiscal L5-S1 fixation observed a faster resolution of the symptoms and a more rapid return to daily activities, especially at 3-6 months' follow-up. The technique is reliable in giving an optimal mechanical stability to obtain a solid fusion. CONCLUSIONS: The advantages of this technique are lower incidence of neurologic complications, speed of execution and faster return to normal life.

Objective skill analysis and assessment in neurosurgery by using an ultra-miniaturized inertial measurement unit WB-3--pilot tests.

In recent years there has been an ever increasing amount of research and development of technologies and methods to improve the quality and the performance of advanced surgery. In several fields, such as laparoscopy, various training methods and metrics have been proposed, both to improve the surgeon's abilities and also to assess her/his skills. For neurosurgery, however, the extremely small movements and target operating space involved have prevented until now the development of similar methodologies and systems. In this paper we present the development of an ultra-miniaturized Inertial Measurement Unit (IMU) and its application for neurosurgery skill assessment in a simple pick and place scenario. This analysis is a preliminary yet fundamental step to realize a better training/evaluation system for neurosurgeons, and to objectively evaluate and understand how the neurosurgery is performed.

A decomposition of fuzzy relations.

This study is concerned with a decomposition of fuzzy relations, that is their representation with the aid of a certain number of fuzzy sets. We say that some fuzzy sets decompose an original fuzzy refraction if the sum of their Cartesian products approximate the given fuzzy relation. The theoretical underpinnings of the problem are presented along with some linkages with Boolean matrices (such as a Schein rank). Subsequently, we reformulate the decomposition of fuzzy relations as a problem of numeric optimizing and propose a detailed learning scheme leading to a collection of decomposing fuzzy sets. The role of the decomposition in a general class of data compression problems (including those of image compression and rule-based system condensation) is formulated and discussed in detail.

Fractures of the radial head and associated elbow injuries in children.

Fractures of the radial head are frequently associated with elbow injuries in children. Thirty-seven patients with this association treated at the Nancy Children's Hospital were analyzed to ascertain the mechanism and the unfavorable factors of prognosis. The mechanism responsible was a valgus strain on the elbow at the moment of impact, associated with forces of compression and distraction. At an average follow-up of 2 years, 76% excellent and good results were obtained. Conservative treatment was always effective in minimally displaced fractures. With surgical reduction by closed intramedullary pinning (CIMP), there were only three failures in severely displaced fractures. With open reduction, results were always poor; 88% patients with fair and poor results had an associated fracture of the olecranon. The unfavorable prognostic factors were the severity of the initial tilting and displacement, the presence of associated elbow injuries, the inadequacy of reduction, and the open reduction procedure.

Treatment of Langerhans-cell histiocytosis in children. Experience at the Children's Hospital of Nancy.

Forty children who had Langerhans-cell histiocytosis were followed for an average of six years (range, excluding patients who died of the disease, two to fifteen years). The patients were divided into two diagnostic groups: those who had localized disease (involving one bone or more only) and those who had multifocal disease (an osseous lesion and a soft-tissue mass, a skin rash, diabetes insipidus, or generalized disease). Methods of treatment included curettage, bone-grafting, chemotherapy, local or systemic corticosteroids, and radiotherapy. Nineteen of the thirty patients who had localized disease had a complete response to the therapy, four had a partial response, and seven had no response. Twenty-one of these thirty patients had not had a recurrence by the time of the latest follow-up examination; nine had a local recurrence within four years after the initial therapy but had no additional recurrences after treatment of the local recurrence. No recurrence occurred more than four years after the time that the initial diagnosis had been made. Five of the ten patients who had multifocal disease had a complete response to the therapy, two had a partial response, and three had no response. Six patients had a recurrence; four did not. Two patients died of the disease. As a result of this study, we recommend the avoidance of intensive measures of treatment, if possible, and we advise long-term follow-up of these patients.

[Localizations of histiocytosis X in bone]. / Les localisations osseuses de l'histiocytose X.

Histiocytosis X is still of unknown origin. Its clinical patterns are various and it is above all a bone disease of children, mostly boys. It is a tumoral condition basically benign but with a strong tendency toward dissemination and destruction. Its natural history is unpredictable. The authors have reviewed 37 cases after a 44 months mean follow-up for bringing up a better understanding of the role of orthopedic surgery. The diagnosis was always based on biopsies looking for at least two basic signs out of four possible ones. Scintigraphy was used to detect other locations. MRI was used to evaluate the effect of treatment. In single eosinophilic granuloma, curettage was associated with biopsy. Local injections of corticoids may help in spinal locations. In disseminated forms, surgical treatment should be little aggressive, limited to a biopsy of the most superficial lesion. These forms should be treated by radiotherapy corticotherapy and chemotherapy, as well as the aggressive lesions, the extensive ones, the threatening ones and those which are not accessible.

[Correction of malunion of femoral fractures by Ilizarov's device in children]. / Correction des cals vicieux du fémur de l'enfant par l'appareil d'Ilizarov.

Cast immobilisation of femoral fractures in children may sometimes be subject to important displacements. Absence of survey leads to malunions which may make a secondary correction necessary. In two such cases the authors used Ilizarov's external fixation which allowed correction of both angulation and shortening without direct approach. Rapid healing occurred. The authors made a comparative analysis of the different possibilities for treatment of these severe femoral malunions.

[Centro-medullary nailing in fractures of the upper end of the humerus in children and adolescents]. / Embrochage centro-médullaire dans les fractures de l'extrémité supérieure de l'humérus chez l'enfant et l'adolescent.

The authors report a series of 55 fractures of the upper extremity of the humerus in children and adolescents surgically treated by elastic intramedullary nailing. The place of this surgical technique is evaluated in the general treatment of these fractures, which have the prognostic always favorable. The results, with a 1 year follow-up, are all excellent or good on the functional and anatomical plan. The cases of mal union have been rare and the correction is obtained with growth. This way be explained by the capacity of remodeling of the upper humerus. The treatment of fractures of the upper extremity of the humerus is first orthopaedic in children and adolescents, but the osteosynthesis by elastic intramedullary nailing can represent a surgical method of choice in the fractures which are displaced, unstable or which need a thoraco-branchial plaster.

[Cotrel-Dubousset instrumentation in idiopathic scoliosis. Angular results in 70 cases]. / L'instrumentation Cotrel-Dubousset dans la scoliose idiopathique. Les résultats angulaires de 70 cas.

The authors have reviewed 70 cases of idiopathic scoliosis operated on following the Cotrel-Dubousset technique between 1984 and 1987. The patients aged 15.2 years in average, presented with a double major curve still in progress at the thoracic or thoraco-lumbar level. The mean pre operative angle was 49 degrees, reducible to 34 degrees on bending. The goals of the method have been reached: in the three dimensional space the correction was selective with an angular gain of 65 per cent in the frontal plane, 34 per cent in the antero posterior plane and 56 per cent in the horizontal plane the technique allowed the suppression of any post operative immobilization, an early weight bearing with resume of social activities.