Assessment of glenoid inclination on routine clinical radiographs and computed tomography examinations of the shoulder.

BACKGROUND: Accurate assessment of glenoid inclination is of interest for a variety of conditions and procedures. The purpose of this study was to develop an accurate and reproducible measurement for glenoid inclination on standardized anterior-posterior (AP) radiographs and on computed tomography (CT) images. MATERIALS AND METHODS: Three consistently identifiable angles were defined: Angle α by line AB connecting the superior and inferior glenoid tubercle (glenoid fossa) and the line identifying the scapular spine; angle β by line AB and the floor of the supraspinatus fossa; angle γ by line AB and the lateral margin of the scapula. Experimental study: these 3 angles were measured in function of the scapular position to test their resistance to rotation. Conventional AP radiographs and CT scans were acquired in extension/flexion and internal/external rotation in a range up to ±40°. Clinical study: the inter-rater reliability of all angles was assessed on AP radiographs and CT scans of 60 patients (30 with proximal humeral fractures, 30 with osteoarthritis) by 2 independent observers. RESULTS: The experimental study showed that angle α and β have a resistance to rotation of up to ±20°. The deviation from neutral position was not more than ±10°. The results for the inter-rater reliability analyzed by Bland-Altman plots for the angle β fracture group were (mean ± standard deviation) -0.1 ± 4.2 for radiographs and -0.3 ± 3.3 for CT scans; and for the osteoarthritis group were -1.2 ± 3.8 for radiographs and -3.0 ± 3.6 for CT scans. CONCLUSION: Angle β is the most reproducible measurement for glenoid inclination on conventional AP radiographs, providing a resistance to positional variability of the scapula and a good inter-rater reliability.

A musculoskeletal shoulder model based on pseudo-inverse and null-space optimization.

The goal of the present work was assess the feasibility of using a pseudo-inverse and null-space optimization approach in the modeling of the shoulder biomechanics. The method was applied to a simplified musculoskeletal shoulder model. The mechanical system consisted in the arm, and the external forces were the arm weight, 6 scapulo-humeral muscles and the reaction at the glenohumeral joint, which was considered as a spherical joint. The muscle wrapping was considered around the humeral head assumed spherical. The dynamical equations were solved in a Lagrangian approach. The mathematical redundancy of the mechanical system was solved in two steps: a pseudo-inverse optimization to minimize the square of the muscle stress and a null-space optimization to restrict the muscle force to physiological limits. Several movements were simulated. The mathematical and numerical aspects of the constrained redundancy problem were efficiently solved by the proposed method. The prediction of muscle moment arms was consistent with cadaveric measurements and the joint reaction force was consistent with in vivo measurements. This preliminary work demonstrated that the developed algorithm has a great potential for more complex musculoskeletal modeling of the shoulder joint. In particular it could be further applied to a non-spherical joint model, allowing for the natural translation of the humeral head in the glenoid fossa.

Avaliação cefalométrica do comportamento da mandíbula na interceptação da má oclusão classe II divisão 1 de Angle, com aparelho bionator

Pós-graduação em Ciências Odontológicas - FOAR

Efectos de los aparatos propulsores mandibulares fijos en la articulación temporomandibular

Fixed mandibular propulsion appliances are an alternative for the treatment of Class II malocclusion in individuals with mandibular deficiency. Since they are fixed appliances, said devices keep the mandible in an anterior-forced position during rest and during all mandibular functions. When a propulsive appliance is used, the lower jaw is displaced forward and downward. This movement leads to a new position of the condyle, which can, ultimately affect the normal functioning of the temporomandibular joint (TMJ). The aim of this paper was to review effects of fixed mandibular propulsive appliance on TMJ. Inclusion criteria considered studies on animals or humans using TMJ radiography, computed tomography, and magnetic resonance imaging. Studies confirm a favorable relation between condyle and glenoid fossa following treatment with fixed mandibular propulsion appliances.

Avaliação tomográfica no tratamento com Herbst em adulto jovem

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

MRI analysis of the relationship between bone changes in the temporomandibular joint and articular disc position in symptomatic patients

Objectives: The aim of this study was to investigate bone changes in the condyle, articular eminence and glenoid fossa in relation to the position of the articular disc. Methods: 148 temporomandibular joints (TMJs) of 74 symptomatic patients who underwent MRI were evaluated. The position of the disc was classified as either normal (N), disc displacement with reduction (DDwR), disc displacement without reduction (DDwoR) and posterior displacement (PD). Bone changes were investigated in the condyle and temporal components of the TMJ and classified as osteophytosis, sclerosis or erosion. Results: There were no bone changes in the glenoid fossa of the temporal bone. Of the total number of TMJs studied, 94 (63.5%) were N, 34 (23%) presented DDwoR, 19 (12.8%) presented DDwR and 1 (0.7%) presented PD. The bone changes in the condyle and posterior aspect of the articular eminence were associated with the position of the disc. The bone changes in the anterior aspect of the articular eminence were not associated with the position of the disc. Conclusion: In cases of DDwoR, bone changes in the condyles were more common. The combination of erosion and osteophytosis in the condyle and the bone changes of the posterior aspect of the articular eminence were associated with disc position. Dentomaxillofacial Radiology (2012) 41, 367-372. doi: 10.1259/dmfr/79317853

In vivo evaluation of the translations of the gleno-humeral joint using Magnetic resonance imaging

Gleno-humeral joint (GHJ) is the most mobile joint of the human body. This is related to theincongr uence between the large humeral head articulating with the much smaller glenoid (ratio 3:1). The GHJ laxity is the ability of the humeral head to be passively translated on the glenoid fossa and, when physiological, it guarantees the normal range of motion of the joint. Three-dimensional GHJ linear displacements have been measured, both in vivo and in vitro by means of different instrumental techniques. In vivo gleno-humeral displacements have been assessed by means of stereophotogrammetry, electromagnetic tracking sensors, and bio-imaging techniques. Both stereophotogrammetric systems and electromagnetic tracking devices, due to the deformation of the soft tissues surrounding the bones, are not capable to accurately assess small displacements, such as gleno-humeral joint translations. The bio-imaging techniques can ensure for an accurate joint kinematic (linear and angular displacement) description, but, due to the radiation exposure, most of these techniques, such as computer tomography or fluoroscopy, are invasive for patients. Among the bioimaging techniques, an alternative which could provide an acceptable level of accuracy and that is innocuous for patients is represented by magnetic resonance imaging (MRI). Unfortunately, only few studies have been conducted for three-dimensional analysis and very limited data is available in situations where preset loads are being applied. The general aim of this doctoral thesis is to develop a non-invasive methodology based on open-MRI for in-vivo evaluation of the gleno-humeral translation components in healthy subjects under the application of external loads.

Transillumination-guided Study of the Endoscopic Anatomy of the Lacrimal Fossa

Dacryocystorhinostomy is the treatment of choice for the obstruction of the lachrymal apparatus. At the end of last century, the development of the endoscopic instruments for nasosinusal surgery has made it possible to do it through the endoscopic pathway. Nonetheless, anatomical variations make it difficult to have reproducibility endonasaly. Aim: study the endoscopic anatomy of the lachrymal fossa through transillumination of the common canaliculus. Study design: experimental. Materials and Methods: we dissected 40 lachrymal pathways from 20 human cadavers, in three stages: 1. identification and dilation of the lachrymal canaliculus. 2 Optic fiber beam introduction; 3 - endoscopic dissection of the lachrymal sac, describing its position. Results: the most frequent position of the lachrymal sac was between the free border of the middle turbinate and its insertion immediately underneath it. The maxillary line was seen in 95% of the cases. Septoplasty was needed in 12.5%, unicifectomy in 35% and middle turbinectomy in 7.5%. Conclusion: Although the lachrymal sac has a more frequent location, its position varied considerably. The transillumination of the common canaliculus proved useful, solving the problem of the anatomical variability.

Tentorial Posterior Fossa Meningioma Which Is the Ideal Surgical Approach: Supra/Infratentorial Combined or Retrosigmoid?

Tentorial meningiomas account for 2% to 3% of all intracranial meningiomas. The authors present their experience with posterior fossa tentorial meningiomas, and discuss the main features, which influence approaches and complications of the different surgical techniques. Twenty-four patients had meningiomas localized predominantly in posterior fossa. Their historical records and radiologic examinations were reviewed in accordance with Simpson`s classification. The extension of tumor removal was Simpson grade I in 12 patients (50%), grade II in 12 patients (50%), and grades III and IV in none of the patients. In 22 patients (91.66%), the meningioma was classified as grade I and in 2 cases (8.33%) classified as grade 11 (atypical meningioma). The combined supra/infiratentorial was employed in 12 cases, and complete resections were most common with this approach compared with retrosigmoid technique. Postoperative complications occurred in 10 patients (41.6%) with major deficits in 3 patients (12.5%). The authors believe that careful preoperative choice of the surgical approach should be based Oil tumor location and extension. It is then possible to achieve the best radical microsurgical tumor resection, avoiding additional injury to neurovascular structures.

Endoscopic Anatomy of the Pterygopalatine Fossa and the Transpterygoid Approach: Development of a Surgical Instruction Model

Introduction: The pterygopalatine fossa (PPF) is a narrow space located between the posterior wall of the antrum and the pterygoid plates. Surgical access to the PPF is difficult because of its protected position and its complex neurovascular anatomy. Endonasal approaches using rod lens endoscopes, however, provide better visualization of this area and are associated with less morbidity than external approaches. Our aim was to develop a simple anatomical model using cadaveric specimens injected with intravascular colored silicone to demonstrate the endoscopic anatomy of the PPF. This model could be used for surgical instruction of the transpterygoid approach. Methods: We dissected six PPF in three cadaveric specimens prepared with intravascular injection of colored material using two different injection techniques. An endoscopic endonasal approach, including a wide nasoantral window and removal of the posterior antrum wall, provided access to the PPF. Results: We produced our best anatomical model injecting colored silicone via the common carotid artery. We found that, using an endoscopic approach, a retrograde dissection of the sphenopalatine artery helped to identify the internal maxillary artery (IMA) and its branches. Neural structures were identified deeper to the vascular elements. Notable anatomical landmarks for the endoscopic surgeon are the vidian nerve and its canal that leads to the petrous portion of the internal carotid artery (ICA), and the foramen rotundum, and V2 that leads to Meckel`s cave in the middle cranial fossa. These two nerves, vidian and V2, are separated by a pyramidal shaped bone and its apex marks the ICA. Conclusion: Our anatomical model provides the means to learn the endoscopic anatomy of the PPF and may be used for the simulation of surgical techniques. An endoscopic endonasal approach provides adequate exposure to all anatomical structures within the PPF. These structures may be used as landmarks to identify and control deeper neurovascular structures. The significance is that an anatomical model facilitates learning the surgical anatomy and the acquisition of surgical skills. A dissection superficial to the vascular structures preserves the neural elements. These nerves and their bony foramina, such as the vidian nerve and V2, are critical anatomical landmarks to identify and control the ICA at the skull base.

Polyploidy in atypical grade II choroid plexus papilloma of the posterior fossa

Cytogenetic studies of choroid plexus tumors, particularly for atypical choroid plexus papillomas, have been rarely described. In the present report, the cytogenetic investigation of an atypical choroid plexus papilloma occurring at the posterior fossa of a 16-year-old male is described. Comparative genome hybridization analysis demonstrated gains of genetic material from almost all chromosomes. Chromosome losses involved 19p, regional losses at chromosome X and loss of chromosome Y. The presence of polyploid cells was confirmed by fluorescence in situ hybridization analysis with probes directed to centromeric regions. Furthermore, the microscopic analysis of cultures showed nuclear buds, nucleoplasmic bridges, and micronuclei in 23% of tumor cells suggesting the presence of complex chromosomal abnormalities. Previous cytogenetic studies on choroid plexus papillomas showed either normal, hypodiploid or hyperdiploid karyotypes. To the best of our knowledge, this is the first report of polyploidy in choroid plexus papilloma of intermediate malignancy grade. Although the mechanisms beneath such genome duplication remain to be elucidated, the observed abnormal nuclear shapes indicate constant restructuring of the tumor`s genome and deserves further investigation.

Hydrocephalus in posterior fossa tumors in children. Are there factors that determine a need for permanent cerebrospinal fluid diversion?

We searched for factors that could predispose towards persistent hydrocephalus in children with posterior fossa (PF) tumors in order to determine the need for permanent cerebrospinal fluid (CSF) diversion. The clinical records of 64 children who underwent surgery for PF tumors in the Pediatric Neurosurgery division of the Hospital of Clinics, Ribeirao Preto, Brazil, from 1990 to 2006, were retrospectively reviewed. The patients` ages ranged from 3 months to 18 years. The factors evaluated included age at surgery, severity of hydrocephalus (ventricular index), tumor location, size of the tumor, extent of tumor resection, and histology. Ventricular index, measured from the initial neuroradiological image, age at surgery, and location of the tumor were significantly associated with definitive postoperative CSF diversion (shunt or endoscopic third ventriculostomy), which was necessary for 34% of the patients. Young children with severe preoperative hydrocephalus and a midline tumor should be considered at risk when preoperative treatment decisions are made.

Galectin-3 expression: a useful tool in the differential diagnosis of posterior fossa tumors in children

Galectin-3 (Gal-3) is a glycan-binding protein highly expressed in several tumors, including brain neoplasms. This protein has been demonstrated to be correlated with adverse prognosis in some tumor types. However, the role of Gal-3 in pediatric posterior fossa tumors (PPFTs) has not yet been fully addressed. The goals of this study were to evaluate Gal-3 expression in a series of PPFTs and verify whether this expression is related to patient outcome. Gal-3 expression was analyzed by immunohistochemistry in 42 cases of surgically resected primary PPFTs. Surgeries were performed in our institution from January 2003 to December 2006. Tumor samples consisted of 21 pilocytic astrocytomas (PAs), 13 medulloblastomas, 4 ependymomas, 2 diffuse cerebellar astrocytomas, and 2 atypical teratoid/rhabdoid tumors (AT/RTs). All PAs and ependymomas strongly showed Gal-3 expression, whereas no immunostaining was observed in medulloblastomas and diffuse astrocytomas. In AT/RTs, Gal-3 expression was conspicuous but heterogeneous, being mainly observed in rhabdoid cells. Concerning the Gal-3 expressing tumors, no relationship was observed between the degree of expression and patient survival. Gal-3 was strongly expressed in reactive astrocytes, normal endothelial cells, and macrophages in the adjacent non-neoplastic brain parenchyma. Interestingly, the endothelial cells in the tumor bulk of PAs lacked Gal-3 expression. Gal-3 is differentially expressed in PPFTs, but its expression shows no correlation with patient outcome. However, the evaluation of Gal-3 is helpful in establishing a differential diagnosis among PPFTs, especially between PAs and diffuse astrocytomas, and in some circumstances between medulloblastomas and AT/RTs.