Forestier's syndrome : a rare cause of dysphagia. A case report and review of the literature.

We report a 72-year-old male with Forestier's syndrome suffering of dysphagia due to an anterior cervical calcification, unusually great in both volume and extent. Its resection by anterior approach allowed the immediate restoration of a normal swallowing. A bony resection is sufficient in case of Forestier's syndrome, but it must be associated with fixation in case of degenerative osteophyte with disc instability. Long-term follow-up is necessary because the recurrence of the calcification is slow but frequent.

Radiographic analysis of the listhesis associated with lumbar isthmic spondylolysis.

BACKGROUND: In cases of spondylolysis, hypoplasia of L5 mimicking spondylolisthesis has been described, mainly based on MRI; however, the treatment implications have not been analyzed specifically. OBJECTIVE: Assess the impact of hypoplasia of the L5 vertebral body in the constitution of the spondylolisthesis associated with isthmic spondylolysis. MATERIAL AND METHODS: A retrospective radiographic study in the standing position was performed with 104 patients with L5 isthmic spondylolysis and 24 control subjects. RESULTS: Measurements of vertebral endplate length showed that the standard apparent posterior listhesis (APL) is made up of true listhesis (TL) and false listhesis (FL). FL is induced by hypoplasia of the L5 vertebral body relative to the S1 endplate. TL results from disk failure and leads to anterior listhesis (AL), which alters the balance of spinal curvatures. CONCLUSIONS: By integrating the potential for false listhesis into the classification systems for spondylolisthesis, we can adapt the treatment algorithms. TYPE OF STUDY: Retrospective radiography study. LEVEL OF EVIDENCE: IV Retrospective review of cases.

Influence of a variation in the position of the arms on the sagittal connection of the gravity line with the spinal structures.

PURPOSE: To evaluate the influence of the position of the arms on the location of the body's gravity line. PREVIOUS DATA: The sagittal balance of the pelvi-spinal unit is organized so that the gravity line is localized in a way that limits the mechanical loads and the muscle efforts. This position of the gravity line was analyzed in vivo, in standing position, the arms dangling, by the barycentremeter, a gamma rays scanner. Then, several teams had the same purpose but using a force platform combined with radiographies. Their results differed significantly among themselves and with the data of the barycentremetry. However, in these studies, the positions of the arms varied noticeably, either slightly bent forwards on a support, or the fingers on the clavicles or on the cheeks. METHODS: We estimated, for each varied posture of the arms, the sagittal coordinates of the masses of the upper limbs and their influence on the anatomical position of the gravity line of the whole body. RESULTS: Using a simple equation and the data of the barycentremeter, we observed that the variations in the location of the gravity line were proportionally connected to the changes of the sagittal position of the mass of the upper limbs induced by the various positions of the arms. CONCLUSIONS: We conclude in a validation of the data of the barycentremeter, as well as of the data obtained by the force platforms as long as the artifact of the position of the arms is taken into account.

Pelvic incidence: a predictive factor for three-dimensional acetabular orientation-a preliminary study.

Acetabular cup orientation (inclination and anteversion) is a fundamental topic in orthopaedics and depends on pelvis tilt (positional parameter) emphasising the notion of a safe range of pelvis tilt. The hypothesis was that pelvic incidence (morphologic parameter) could yield a more accurate and reliable assessment than pelvis tilt. The aim was to find out a predictive equation of acetabular 3D orientation parameters which were determined by pelvic incidence to include in the model. The second aim was to consider the asymmetry between the right and left acetabulae. Twelve pelvic anatomic specimens were measured with an electromagnetic Fastrak system (Polhemus Society) providing 3D position of anatomical landmarks to allow measurement of acetabular and pelvic parameters. Acetabulum and pelvis data were correlated by a Spearman matrix. A robust linear regression analysis provided prediction of acetabulum axes. The orientation of each acetabulum could be predicted by the incidence. The incidence is correlated with the morphology of acetabula. The asymmetry of the acetabular roof was correlated with pelvic incidence. This study allowed analysis of relationships of acetabular orientation and pelvic incidence. Pelvic incidence (morphologic parameter) could determine the safe range of pelvis tilt (positional parameter) for an individual and not a group.

[Medical education under the Revolution and the Empire]. / L'enseignement de la médecine sous le Révolution et l'Empire.

After the suppression of medical education during the French revolution in 1793, the lack of caregivers is dramatic, especially in the army. The medical education is therefore rehabilitated in 1794 in 3 (then 6) Health Schools, which will become Schools of Medicine and Faculties of Medicine, incorporated in 1808 into then Imperial University. During 3 years, the courses are theoretical and also based on a practical teaching on the patient. The defense of a thesis provides access to the title of doctor in medicine or surgery and allows practicing for all the pathologies on the entire territory of the Empire. Meanwhile, medical courses are given in military hospitals to train officers of health. They are dedicated for the service of the army and for minor diseases in rural areas. They are authorized to practice only in the department in which they were received. The inspectors general provide medical education directly in the military medical structures and conduct examinations about medical care. This type of career is illustrated by the biography of Surgeon Major François Augustin Legaÿ.

How is sagittal balance acquired during bipedal gait acquisition? Comparison of neonatal and adult pelves in three dimensions. Evolutionary implications.

We compare adult and intact neonatal pelves, using a pelvic sagittal variable, the angle of sacral incidence, which presents significant correlations with vertebral curvature in adults and plays an important role in sagittal balance of the trunk on the lower limbs. Since the lumbar curvature develops in the child in association with gait acquisition, we expect a change in this angle during growth which could contribute to the acquisition of sagittal balance. To understand the mechanisms underlying the sagittal balance in the evolution of human bipedalism, we also measure the angle of incidence of hominid fossils. Fourty-seven landmarks were digitized on 50 adult and 19 intact neonatal pelves. We used a three-dimensional model of the pelvis (DE-VISU program) which calculates the angle of sacral incidence and related functional variables. Cross-sectional data from newborns and adults show that the angle of sacral incidence increases and becomes negatively correlated with the sacro-acetabular distance. During ontogeny the sacrum becomes curved, tends to sink down between the iliac blades as a wedge and moves backward in the sagittal plane relative to the acetabula, thus contributing to the backwards displacement of the center of gravity of the trunk. A chain of correlations links the degree of the sacral slope and of the angle of incidence, which is tightly linked with the lumbar lordosis. We sketch a model showing the coordinated changes occurring in the pelvis and vertebral column during the acquisition of bipedalism in infancy. In the australopithecine pelves, Sts 14 and AL 288-1, and in the Homo erectus Gona pelvis the angle of sacral incidence reaches the mean values of humans. Discussing the incomplete pelves of Ardipithecus ramidus, Australopithecus sediba and the Nariokotome Boy, we suggest how the functional linkage between pelvis and spine, observed in humans, could have emerged during hominid evolution.

Relationship between sacral pelvic incidence and acetabular orientation.

The importance of the sacral pelvic incidence (SPI) in relation to individual variations of sagittal spinal curvature has become well-recognised. We attempted to determine the relationship between SPI and acetabular orientation. The three-dimensional coordinates of 47 homologous points were observed on 51 adult anatomical pelvises (26 female and 25 male). The reference vertical plane was Lewinnek's anterior pelvic plane. 10 angular parameters and 11 linear parameters were defined and calculated. These were expressed both in absolute value (in millimetres) and in "acetabular unit" (relative to the mean value of the right and left acetabular rays). Mean values of the parameters were calculated for all pelvises and according to gender. There were two dominant parameters: the "sacral slope" and the "V pubic angle". "Acetabular tilting" was primarily dependent on the "sacral slope" and its intermediary on the "SPI", while "acetabular anteversion" dependent on the "V pubic angle" via the "angle of prow". It is recommended that positioning of the acetabular cup in total hip arthroplasty relates to anatomical parameters, and to the global sagittal balance of the pelvi-spinal unit.

Influence of the sagittal balance of the spine on the anterior pelvic plane and on the acetabular orientation.

The Anterior Pelvic Plane (APP), defined by the anterior superior iliac spines and the pubic tubercle, was commonly used as reference for positioning and postoperative evaluation of the orientation of the acetabular cup in total hip arthroplasty. APP was assumed to be vertical, but was not observed always so, mostly because of associated spinal diseases inducing perturbations in the harmony of the sagittal balance of the pelvi-spinal unit. Consequently a sagittal rotation of the pelvis occurs, and so a tilt of the APP which alters directly the orientation of the cup in upright position. An analysis of the APP tilt related to the sagittal balance of the spine was provided and its implication on the cup orientation. It appeared essential for an individual adjustment of the cup positioning to avoid a functional mal-position which can lead to an increased risk of dislocation and impingement.

Cervical spondylolysis in a child: a case with hypermobility.

BACKGROUND CONTEXT: Cervical spondylolysis (CS) is a rare disorder involving a cleft in the articular mass, at the junction of the superior and inferior facet joints, and often a complex malformation of the posterior elements of the vertebra. The most commonly affected level is the sixth cervical vertebra. Most of the cases are adults. Its origin, mechanical or embryological, is controversial. PURPOSE: To report the case in a young boy and to outline the imaging findings related to the causal mechanism. STUDY DESIGN: A case report. PATIENT SAMPLE: A 7-year-old boy with CS of the sixth cervical vertebra discovered after a minimal trauma. METHODS: Radiological observation and literature review. RESULTS: A forward listhesis in extension is observed despite an intact disc on magnetic resonance imaging, expressing the loads applied to the dysplastic vertebra before the mechanical failure of the vertebral structures occurs. CONCLUSIONS: A mixed origin, both mechanical and congenital is suggested. It is proposed that the CS results from microimpacts because of the cervical spine biomechanics affecting a posterior arch prone to develop a cleft as a result of associated malformations.

The femoro-sacral posterior angle: an anatomical sagittal pelvic parameter usable with dome-shaped sacrum.

The sagittal pelvic morphology modulates the individual alignment of the spine. Anatomical angular parameters were described as follows: the "Pelvic Incidence" (PI) and the Jackson's angle "Pelvic Lordosis" (PR-S1). Significant chains of relationships were expressed connecting these angles with pelvic and spinal positional parameters. This allows an individual assessment of the harmony of the sagittal spinal balance. But in case of spondylolysis with high-grade listhesis, the upper plate of the sacrum shows a dome-shaped deformity. The previous anatomical parameters are therefore imprecise. Indeed, the anterior part of the sacrum being inaccurate, an exact assessment of these angles becomes impossible. Therefore, we propose a new angular parameter named "Femoro-Sacral Posterior Angle" (FSPA): the angle between the posterior wall of the first sacral vertebra, always well definite, and the line connecting the posterior part of the sacral plate to the femoral axis. The validation of this parameter was performed and compared with the classical published parameters. It showed good inter-observer reliability, even with dome-shaped sacral plate. In spite of lower correlation with the positional parameters than those observed with PI or PR-S1, the FSPA appeared to be reliable and precise for an exact evaluation of the sagittal spino-pelvic balance is case of spondylo-listhesis with dome-shaped sacral endplate.

Three-dimensional study of pelvic asymmetry on anatomical specimens and its clinical perspectives.

The aim of this study was to assess pelvic asymmetry (i.e. to determine whether the right iliac bone and the right part of the sacrum are mirror images of the left), both quantitatively and qualitatively, using three-dimensional measurements. Pelvic symmetry was described osteologically using a common reference coordinate system for a large sample of pelvises. Landmarks were established on 12 anatomical specimens with an electromagnetic Fastrak system. Seventy-one paired variables were tested with a paired t-test and a non-parametric test (Wilcoxon). A Pearson correlation matrix between the right and left values of the same variable was applied exclusively to values that were significantly asymmetric in order to calculate a dimensionless asymmetry index, ABGi, for each variable. Fifteen variables were significantly asymmetric and correlated with the right vs. left sides for the following anatomical regions: sacrum, iliac blades, iliac width, acetabulum and the superior lunate surface of the acetabulum. ABGi values above a threshold of +/- 4.8% were considered significantly asymmetric in seven variables of the pelvic area. Total asymmetry involving the right and the left pelvis seems to follow a spiral path in the pelvis; in the upper part, the iliac blades rotate clockwise, and in the lower part, the pubic symphysis rotates anticlockwise. Thus, pelvic asymmetry may be evaluated in clinical examinations by measuring iliac crest orientation.

Sagittal plane alignment of the spine and gravity: a radiological and clinical evaluation.

Analysis of the sagittal balance of the spine includes the study of the spinal curves and of the pelvis in the sagittal plane. It therefore requires full-spine lateral radiographs. The sagittal balance of the spine was studied in forty-nine young adults. Strong correlations were observed between parameters related to the pelvis ("pelvic incidence angle", "sacral slope" and "pelvic tilting"), and the sagittal spinal curves ("lordosis" and "kyphosis"). We therefore propose to begin the evaluation of the sagittal plane alignment of the spine in clinical practice with measurement of the pelvic incidence angle. The relationship between the pelvic incidence angle and the sacral slope, as well as between the sacral slope and lordosis, is then assessed, and these are related to each other. The use of a graphic abacus facilitates assessment of the physiological comparison of the measured values and of the relationship between pelvic and spinal parameters, within their range of physiological variability. This analysis of the sagittal alignment of the spine also considers its dynamic aspect and the importance of gravity load and of muscular contraction on the lumbar structures. These data have been published previously and are recalled here. Three basic patterns of disruption of the relations between parameters may be encountered: a sacral slope angle exceeding the value expected considering the measured pelvic incidence angle (owing to fixed flexion contracture of the hips), excessive lordosis with regard to the observed sacral slope angle (with hyperkyphosis at the thoracic level) and stiff hypolordosis with pelvic retroversion. These three conditions are analysed in the light of the repercussions of the gravity load on the lumbar structures. A convenient method is thus available for functional analysis of the sagittal balance of the spine.