Biomedical subjects

Hubert Labelle

Publications and source records attributed to Hubert Labelle.

57 records · Page 4Linked to original sources

PubMed2002

3D reconstruction and analysis of the whole trunk surface for non-invasive follow-up of scoliotic deformities.

The purpose of this study was to evaluate the 3D reconstruction accuracy of a new technology that allows the acquisition of the whole trunk and to develop a software to analyse the trunk surface asymmetry. A non-invasive active vision system provides a 3D textured reconstruction of the whole trunk. The analysis system provides the clinician with quantitative indices that characterize the whole external trunk asymmetry.

Artificial Intelligence↗

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↗

PubMedDate not supplied

3D/2D registration and segmentation of scoliotic vertebrae using statistical models.

We propose a new 3D/2D registration method for vertebrae of the scoliotic spine, using two conventional radiographic views (postero-anterior and lateral), and a priori global knowledge of the geometric structure of each vertebra. This geometric knowledge is efficiently captured by a statistical deformable template integrating a set of admissible deformations, expressed by the first modes of variation in Karhunen-Loeve expansion, of the pathological deformations observed on a representative scoliotic vertebra population. The proposed registration method consists of fitting the projections of this deformable template with the preliminary segmented contours of the corresponding vertebra on the two radiographic views. The 3D/2D registration problem is stated as the minimization of a cost function for each vertebra and solved with a gradient descent technique. Registration of the spine is then done vertebra by vertebra. The proposed method efficiently provides accurate 3D reconstruction of each scoliotic vertebra and, consequently, it also provides accurate knowledge of the 3D structure of the whole scoliotic spine. This registration method has been successfully tested on several biplanar radiographic images and validated on 57 scoliotic vertebrae. The validation results reported in this paper demonstrate that the proposed statistical scheme performs better than other conventional 3D reconstruction methods.

Humans↗