Biomedical subjects

Véronique Feipel

Publications and source records attributed to Véronique Feipel.

11 recordsLinked to original sources

PubMed2006

Low-dose computed tomography: a solution for in vivo medical imaging and accurate patient-specific 3D bone modeling?

BACKGROUND: The number of in vivo clinical biomedical experiments based on computed tomography is increasing. International radiation-protection bodies are promoting the use of low-dose computed tomography to reduce radiation absorption by the subject undergoing imaging. On the other hand no data exist in the literature to quantify whether or not low-dose computed tomography would lead to a decrease of result quality when used for three-dimensional bone modeling and related measurements. METHODS: This paper aimed at finding a consensus between minimal X-ray radiation of the subject, and satisfactory image data quality, especially for accurate three-dimensional bone modeling. Several standard computed tomography and low-dose computed tomography sequences were analyzed in three tests and statistically compared. FINDINGS: Absence of significant difference between standard and low-dose computed sequences indicated that the low-dose setting would not produce less accurate three-dimensional models, while it decreased the effective X-ray dose up to 90% compared to standard settings. INTERPRETATION: Low-dose computed tomography seems suitable for accurate three-dimensional bone modeling, while the related effective X-ray radiation is low. Such setting is therefore advised for any in vivo medical imaging aiming to collect bone data.

Bone and Bones↗

PubMed2006

Clinical and goniometric evaluation of patients with spasmodic torticollis.

BACKGROUND: Patients with cervical dystonia have been evaluated prospectively by the Toronto Western Spasmodic Torticollis Rating Scale and by cervical electrogoniometry. METHODS: Nineteen patients with cervical dystonia were studied. The Toronto Scale interobserver reliability was evaluated by two observers. An electrogoniometer was used to quantify cervical range of motion and velocity. The correlation between goniometric measurements and clinical evaluation was calculated. FINDINGS: The interobserver reliability was excellent for the total score (r(s) = 99) and good for the disability and the pain score (r > 0.88). However, global severity scale was shown to have a moderate reliability (r = 0.63) with r ranging from 0.37 to 0.98 for the individual items. The average loss of range of motion for flexion and extension, lateral bending and rotation was 18%, 12% and 21% respectively. For the velocity of movement, the average loss was proportionately greater than for the range of motion. (41%, 43% and 52% respectively). Correlation between the severity scale and range of motion was moderate but significant (r(s) = -0.52 to -0.67). Correlation between the Toronto severity score and the sum of movement velocities was significant for flexion-extension and lateral bending velocity sums (r(s) = -0.51; r(s) = -0.61). The lateral bending and rotation velocities were significantly correlated with pain and total scores (r(s) = -0.51). No significant correlation was observed for the disability score. INTERPRETATION: Three-dimensional electrogoniometry is helpful to quantify the velocity of neck movements and range of motion in patients with cervical dystonia.

Biomechanical Phenomena↗

PubMed2006

In vivo registration of both electrogoniometry and medical imaging: development and application on the ankle joint complex.

An in vivo method for joint kinematics visualization and analysis is described. Low-dose computed tomography allowed three-dimensional joint modeling, and electrogoniometry collected joint kinematic data. Data registration occurred using palpated anatomical landmarks to obtain interactive computer joint simulation. The method was applied on one volunteer's ankle, and reproducibility was tested (maximal discrepancy: 3.6 deg and 5.5 mm for rotation and translation respectively).

Ankle Joint↗

PubMed2006

Involvement of the anterior portion of the subacromial-subdeltoid bursa in the painful shoulder.

OBJECTIVE: The purpose of our study was to verify that increased widening of the anterior portion of the subacromial-subdeltoid bursa is associated with anteromedial shoulder pain. MATERIALS AND METHODS: Bursography, sonography, and CT were performed in six cadaver shoulders and compared with anatomic sections in neutral position and while the humerus was extended and internally rotated. For the clinical study, the width of the anterior portion of the bursa was measured in both positions in both shoulders of 27 patients referred because of shoulder pain and in eight asymptomatic volunteers. Pain was coded as absent, experienced in the anteromedial portion of the shoulder, or experienced elsewhere but not anteromedially, and we compared the pain scores between shoulder positions. RESULTS: In all cadaver shoulders, when compared with CT scans and anatomic sections, sonography showed the morphology of the bursa, its relationships with surrounding structures, and morphologic changes associated with position. In volunteers, the mean width of the bursa was 0.74 +/- 0.05 and 0.93 +/- 0.09 mm (p = 0.013), respectively, in neutral and stress position. In patients, the same values were 0.70 +/- 0.07 and 0.81 +/- 0.14 mm (p = 0.286) in the asymptomatic side and 1.20 +/- 0.11 and 1.75 +/- 0.23 mm (p < 0.001) in the symptomatic side, respectively. The bursa was wider in patients experiencing pain anteromedially than in those who experienced pain elsewhere and volunteers (p = 0.002 and < 0.001, respectively), and the bursa was wider in symptomatic shoulders than in asymptomatic shoulders (p < 0.001). CONCLUSION: Widening of the anterior portion of the subacromial-subdeltoid bursa is associated with anteromedial shoulder pain and the clinical syndrome of coracoid impingement.

Adult↗

PubMed2004

Calibration and validation of 6 DOFs instrumented spatial linkage for biomechanical applications. A practical approach.

A method for both calibration and validation of a 6 DOF electrogoniometer is presented. A 6 Revolute Instrumented Spatial Linkage (6R-ISL) and a three-dimensional digitizer (3DD) were used simultaneously to collect both static and continuous poses of unconstrained or constrained motions. Validation occurred using a calibrated ball-and-socket joint. A parametrical model of the 6R-ISL (i.e. Virtual Goniometer or VG) was designed using a standard multibody system geometry. Two approaches were used to adjust the VG parameters: a parametrical adjustment of the VG linkage geometry, and a functional adjustment of the potentiometer calibration curves (angle-voltage) in a predefined range of motion. After calibration, 6R-ISL accuracy was better than 1 mm and 1 degrees for translation and orientation, respectively. The functional method presented in this paper can be suggested as a practical approach, which allows on-line checking and calibration of 6R-ISL within the specific range of interest of a particular anatomical joint. In addition, improving the potentiometer calibration curves was less time consuming than the parametrical adjustment.

Algorithms↗

PubMed2003

Sonography detection threshold for knee effusion.

The aim of this study was to determine the threshold for detecting knee effusion by ultrasound (US). Five knee specimens from embalmed cadavers were studied. Intra-articular injection of saline, blood and synovial fluid was performed under ultrasound control and methylene blue dye instillation. The smallest amount of fluid detectable by US in the knee was 7.4 ml for synovial fluid, 10.1 and 10.4 ml for saline solution and 9.7 for blood. The threshold for detecting knee joint effusion by US in cadaver specimens was 10 ml for saline and blood and 7 ml for synovial fluid.

Cadaver↗

PubMed2003

Evaluation of a transpedicular drill guide for pedicle screw placement in the thoracic spine.

Insertion of pedicle screws in the thoracic spine is technically difficult and may lead to major complications. Although many computer-assisted systems have been developed to optimize pedicle screw insertion, these systems are expensive, not user-friendly and involve significant radiation from pre-operative computed tomographic (CT) scan imaging. This study describes and evaluates a transpedicular drill guide (TDG) designed to assist in the proper placement of pedicle screws in the thoracic spine. Pilot holes were made manually using the TDG in the thoracic spine (T1-T11) of three human cadavers before inserting 4.5-mm-diameter screws. CT scans followed by visual inspection of the spines were performed to evaluate the position of the screws. Five of 66 screws (7.6%) violated the pedicle wall: two (3.0%) medially and three (4.5%) laterally. The medial and lateral perforations were within 1 mm and 2 mm of the pedicle wall, respectively. The medial perforations were not at risk of causing neurological complications. No screw penetrated the superior or inferior pedicle wall. The TDG is easy to use and can decrease the incidence of misplaced thoracic pedicle screws. The TDG could be used as a complement to fluoroscopy in certain applications, especially for training surgeons.

Aged↗

PubMed2003

Electrogoniometric and radiologic evaluation of scapho-trapezo-trapezoid arthrodesis.

This article addresses the following questions: after scapho-trapezo-trapezoid (STT) fusion in patients, is the wrist center of rotation (COR) modified during flexion/extension and radioulnar deviations? What is the loss of range of motion (ROM) observed after this procedure? To answer these questions, the authors analyzed the COR in the plan using fluoroscopy and an approach by 3D electrogoniometry using the mean point pivot. This 3D COR was studied during circumduction.

Adult↗

PubMed2003

The use of medical imaging-based kinematic analysis in the evaluation of wrist function and outcome.

The authors developed a 3D CT technique to analyze in vivo variations in carpal bone position based on 3D reconstruction of transverse CT data in 5 wrist positions. The subject groups analyzed consisted of 40 asymptomatic volunteers and 30 patients with various wrist disorders (fractures, instabilities). In 11 anatomic specimens, this kinematic analysis was completed by a radiographic morphologic study and an investigation of capsular ligament anatomy. Clinical applications showed that carpal bone motion in the injured wrist was not significantly different from contralateral, asymptomatic wrist motion. In both wrists of patients with unilateral pathology, however, significant differences were observed as compared with asymptomatic volunteers. Scaphoid motion was bilaterally altered, suggesting the existence of anatomic or kinematic factors predisposing to certain carpal pathologies.

Adult↗

PubMed2002

Use of a transpedicular drill guide for pedicle screw insertion in the thoracic spine.

A transpedicular drill guide (TDG) was designed to assist in the safe placement of pedicle screws in the thoracic spine. In a preliminary study, pilot holes were drilled into the pedicles (T1 to T12) of eight anatomical models in order to compare the conventional anatomical technique to the TDG. Visual inspection of the drilled pedicles was performed. Subsequently in a cadaveric study, pilot holes were made using the TDG in the thoracic spine (T1 to T11) of one human cadaver before inserting 4.5 mm diameter screws. CT scan followed by visual inspection of the cadaveric spine was performed to evaluate the position of the screws. With the anatomical models, 19 of 96 (19.8%) holes drilled using the TDG and 64 of 96 (66.7%) holes drilled using the anatomical technique violated the pedicle wall (p<0.001). The TDG reduced the rate of medial perforation. Ninety-nine percent of the pilot holes made with the TDG were within 2 mm from the pedicle wall compared to 79.2% for the anatomical technique. In the cadaveric study, one of the 22 (4.5%) screws violated the medial wall of the right T1 pedicle by less than 1 mm. No screw penetrated the anterior vertebral cortex, nor the lateral, superior or inferior pedicle wall. The TDG is easy to use and can decrease the incidence of misplaced thoracic pedicle screws. The TDG could be used alone as an alternative to navigation systems in certain applications or with fluoroscopy during thoracic pedicle screw placement, especially for training surgeons.

Bone Screws↗

PubMed1998

A new method for measuring wrist-joint ligament length changes during sagittal and frontal motion.

OBJECTIVE: The present study addresses elongation patterns of selected capsular wrist ligaments during two types of planar wrist motion. DESIGN. IN VITRO: continuous measurement of capsular ligament elongation using miniature displacement transducers. BACKGROUND: The function of the capsular wrist ligaments in carpal kinematics is still to be determined unambiguously. Most previous studies on carpal ligament behaviour were realised using X-ray stereophotogrammetric methods. METHODS: Elongation of the palmar radiolunate, radiocapitate and ulnocapitate ligaments, as well as of the dorsal radiotriquetral ligament during frontal and sagittal wrist motion were analysed in 10 anatomical specimens using miniature differential variable reluctance transducers. Wrist motion was tracked using a six-degree-of-freedom electrogoniometer. RESULTS AND CONCLUSIONS: In most instances, the elongation of these ligaments was similar for two motion modalities tested (guided by a rail or free) with, however, a trend to larger individual variations and smaller elongation during free motion for several ligaments. The capsular ligaments considered in this study displayed length changes inferior to 15% of the initial length. The individual elongation patterns and ranges were highly variable, contrasting with excellent intra-individual reproducibility.

Journal Article↗