Surgical declarative knowledge learning: concept and acceptability study.

Improving surgical training by means of technology assistance is an important challenge that aims to directly impact surgical quality. Surgical training includes the acquisition of two categories of knowledge: declarative knowledge (i.e. 'knowing what') and procedural knowledge (i.e. 'knowing how'). It is essential to acquire both before performing any particular surgery. There are currently many tools for acquiring procedural knowledge, such as simulators. However, few approaches or tools allow a trainer to formalize and record surgical declarative knowledge, and a trainee to have easy access to it. In this paper, we propose an approach for structuring surgical declarative knowledge according to procedural knowledge and based on surgical process modeling. A dedicated software application has been implemented. We evaluated the concept and the software usability on two procedures with different medical populations: endoscopic third ventriculostomy involving 6 neurosurgeons and preparation of a surgical table for craniotomy involving 4 scrub nurses. The results of both studies show that surgical process models could be a well-adapted approach for structuring and visualizing surgical declarative knowledge. The software application was perceived by neurosurgeons and scrub nurses as an innovative tool for managing and presenting surgical knowledge. The preliminary results show that the feasibility of the proposed approach and the acceptability and usability of the corresponding software. Future experiments will study impact of such an approach on knowledge acquisition.

Towards the definition of a patient-specific rehabilitation program for TKA: A new MRI-based approach for the easy volumetric analysis of thigh muscles.

After Total Knee Arthroplasty (TKA), a global post-operative rehabilitation programme is commonly performed. However, this current program is not always adapted to every patient and it could be improved by deeply reinforcing weaker thigh muscles. To do this, a muscle volume estimation coupled with force evaluation is required to therefore adapt the rehabilitation as a specific patient exercise plan. In this paper, we presented an MRI protocol allowing the acquisition of the whole thigh as well as a semi-automated pipeline to segment two main groups of thigh muscles, i.e., the quadriceps femoris and the hamstrings muscles. The pipeline is based on a few cross-sections manually labelled and a 3D-spline interpolation using directed graphs corresponding points. The seven muscles of ten thighs (70 muscles in total) were segmented and reconstructed in 3D. To assess this pipeline, three types of metrics (volumetric similarity, surface distance, and classical measures) were employed. Furthermore, the inter-muscle overlapping was calculated as an additional metric. The results showed mean DICE was 99.6% (±0.1), Hausdorff Distance was 4.9 mm (±1.8) and Absolute Volume Difference was 2.97 cm3 (±1.94) in comparison to the manual ground truth. The average overlap was 2.05% (±0.54).Clinical Relevance- The proposed segmentation method is fast, accurate and possible to integrate in the clinical workflow of TKA.

FCN-based approach for the automatic segmentation of bone surfaces in ultrasound images.

PURPOSE: A new algorithm, based on fully convolutional networks (FCN), is proposed for the automatic localization of the bone interface in ultrasound (US) images. The aim of this paper is to compare and validate this method with (1) a manual segmentation and (2) a state-of-the-art method called confidence in phase symmetry (CPS). METHODS: The dataset used for this study was composed of 1738 US images collected from three volunteers and manually delineated by three experts. The inter- and intra-observer variabilities of this manual delineation were assessed. Images having annotations with an inter-observer variability higher than a confidence threshold were rejected, resulting in 1287 images. Both FCN-based and CPS approaches were studied and compared to the average inter-observer segmentation according to six criteria: recall, precision, F1 score, accuracy, specificity and root-mean-square error (RMSE). RESULTS: The intra- and inter-observer variabilities were inferior to 1 mm for 90% of manual annotations. The RMSE was 1.32 ± 3.70  mm and 5.00 ± 7.70 mm for, respectively, the FCN-based approach and the CPS algorithm. The mean recall, precision, F1 score, accuracy and specificity were, respectively, 62%, 64%, 57%, 80% and 83% for the FCN-based approach and 66%, 34%, 41%, 52% and 43% for the CPS algorithm. CONCLUSION: The FCN-based approach outperforms the CPS algorithm, and the obtained RMSE is similar to the manual segmentation uncertainty.

Non-rigid MRI/CT registration for effective planning of prostate brachytherapy.

Prostate brachytherapy is an intraoperative radiotherapy technique for irradiating prostate tumors by placing radioactive sources inside the prostate. CT image is used to calculate a personalized dose distribution (PDD) while the MRI is used to visualize the tumor and the organs at risk. Therefore, a registration of preoperative MRI and CT is essential since it could improve the overall precision of the treatment planning, the placement of radioactive sources inside the prostate as well as the visualization of the dose distribution with respect to the tumor. This registration should compensate for prostate deformations due to changes in size and form between the acquisitions of each modality. In this paper, we present an intensity-based non-rigid registration method that does not require any manual segmentation or visual identification of landmarks. This method is based on the maximization of the mutual information in combination with a deformation field parameterized by cubic B-Spline. The method was validated on clinical patient datasets; the preliminary evaluation shows encouraging results that satisfy the desired clinical accuracy.

A new optimization approach for the calibration of an ultrasound probe using a 3D optical localizer.

This paper describes a fast procedure for the calibration of an ultrasound (US) probe using a 3D optical localizer. This calibration step allows us to obtain the 3D position of any point located on the 2D ultrasonic (US) image. To carry out correctly this procedure, a phantom of known geometric properties is probed and these geometries are found in the US images. A segmentation step is applied in order to obtain automatically the needed information in the US images and then, an optimization approach is performed to find the optimal calibration parameters. A new optimization method to estimate the calibration parameters for an ultrasound (US) probe is developed.

Leptomeningeal myelomatosis mimicking a subdural haematoma.

We report a rare appearance at presentation of meningeal myelomatosis without bone involvement, in the form of an extraaxial mass of mixed density, resembling a chronic subdural haematoma.

Pagetic sarcoma of the calvarium: report of two cases.

Two cases of calvarium sarcoma with intracranial extension, consecutive to Paget disease of the skull are presented. The neurosurgical implications of this rare complication of a common disease are reviewed. In both cases, the symptoms of malignant degeneration were unspecific and blurred by the presence of a well-known Paget disease. Increasing headaches, focal neurological deficits and signs of intracranial hypertension were observed. Skull X-rays and Computerised Tomography did not allow to make the difference between Pagetic bone and sarcoma. In the second case, Magnetic Resonance Imaging was the most accurate in determining the precise localisation of the tumour, and the subdural invasion. Extensive surgical resection was carried out, by craniectomy of the tumoural bone, followed by cranioplasty. Dural sinus involvement and tumour hypervascularisation caused important peroperative blood loss in both patients. In the second case, the tumour invaded the subdural space through a Pacchioni granulation. Survival of patients with Pagetic sarcoma seems shorter when compared to post-radiation or primitive osteosarcoma, despite adjuvant therapies, probably because of late diagnosis and incomplete surgical resection. The mean reported survival rate is 6 months. Although the first patient died within 4 months, in the second case, the authors obtained a more than two year survival with aggressive surgery alone. These cases also illustrate the polymorphism of sarcomatous degeneration of Pagetic calvarium, the interest of MRI, and the need for close surveillance of patients with known Pagets disease of the skull.

[Dysplasia and spontaneous bilateral dissection of the internal carotid arteries: apropos of a case. Value of surgical treatment]. / Dysplasie et dissection spontanée bilatérale des carotides internes: à propos d'un cas intérêt du traitement chirurgical.

The authors report a case of spontaneous internal carotid artery dissection with a fibromuscular dysplasia of the heterolateral artery. Etiopathogeny, anatomo-pathology, different arteriographic forms and treatment are discussed. The interest of this case is to be found in two aspects: The dysplasia seems to be at the origin of the dissection. It shows that the treatment hereby applied (extra-intracranial bypass) will be of good interest in such situation. The patient became and remain totally asymptomatic 45 months after the second operation.

Dural arteriovenous anomaly fed by ethmoidal arteries.

A case of arteriovenous anomaly of the left ethmoidal groove, exclusively fed by both ophthalmic arteries and draining into the anterior segment of the superior sagittal sinus through a dilated bridging vein of the prefrontal cortex, is reported. Onset of symptoms was with an acute spontaneous intracerebral hematoma. The relation of this anatomo-clinical entity to other intracranial dural arteriovenous lesions is discussed, as well as its pathophysiology and its surgical management.

Bilateral traumatic carotid-cavernous fistulae.

The author reports a case of bilateral traumatic carotid-cavernous fistulae successfully treated by cervical carotid surgery alone. The right fistula was presumably cured by the thrombotic process induced by muscle embolization and carotid ligation (Brooks method). The left shunt was selectively obliterated by controlled embolization with preservation of the carotid permeability (variant of Isamat technique).

Biosynthesis of p-aminophenylalanine: part of a general scheme for the biosynthesis of chorisimic acid derivatives.

p-Aminophenylalanine is biosynthesized in Vigna vexillata (L.) A. Rich. from shikimic acid through a pathway different from that giving phenylalanine and tyrosine. Experiments with 1,6-14C-labelled shikimic acid demonstrate that the C3-side chain in p-aminophenylalanine is attached to the original C-1 in shikimic acid. The biosynthesis of p-aminophenylalanine in Vigna vexillata probably follows the same pathway as the biosynthesis of this amino acid in Streptomyces species where it is known to be an intermediate in the biosynthesis of chloramphenicol. It is proposed that the biosynthesis takes place through chorismic acid, 4-amino-3-enolpyruvylcyclohexa-1,5-dienecarboxylic acid, 3-(4-amino-1-carboxycyclohexa-2,5-dienyl) pyruvic acid, and 4'-aminophenyl-yruvic acid. It is proposed that chorismic acid can gave rise to 4-amino-3-enolpyruvylcyclohexa-1,5-dienecarboxylic acid, 2-amino-3-enolpyruvylcyclohexa-4,6-dienecarboxylic acid, and isochorismic acid, and that these three compounds and chorismic acid itself by simple rearrangements and elimination reactions can give rise to most known chorismic acid derivatives, i. e.p-hydroxybenzoic acid, 3,4-dihydroxy-3,4-dihydrobenzoic acid, phenylalanine, tyrosine, p-aminobenzoic acid, p-aminophenylalanine, anthranilic acid, 2-amino-3-hydroxy-2,3-dihydrobenzoic acid, 3-(3-carobxyphenyl) alanine, 3-(3-carbocy-4-hydrocyphenyl) alanine, salicylic acid, and 2,3-dihydroxy2,3-dihydrobenzoic acid.