Towards Image-Guided Pediatric Atrial Septal Defect Repair

Congenital heart disease occurs in 107.6 out of 10,000 live births, with Atrial Septal Defects (ASD) accounting for 10\% of these conditions. Historically, ASDs were treated with open heart surgery using cardiopulmonary bypass, allowing a patch to be sewn over the defect. In 1976, King et al. demonstrated use of a transcatheter occlusion procedure, thus reducing the invasiveness of ASD repair. Localization during these catheter based procedures traditionally has relied on bi-plane fluoroscopy; more recently trans-esophageal echocardiography (TEE) and intra-cardiac echocardiography (ICE) have been used to navigate these procedures. Although there is a high success rate using the transcatheter occlusion procedure, fluoroscopy poses radiation dose risk to both patient and clinician. The impact of this dose to the patients is important as many of those undergoing this procedure are children, who have an increased risk associated with radiation exposure. Their longer life expectancy than adults provides a larger window of opportunity for expressing the damaging effects of ionizing radiation. In addition, epidemiologic studies of exposed populations have demonstrated that children are considerably more sensitive to the carcinogenic effects radiation. Image-guided surgery (IGS) uses pre-operative and intra-operative images to guide surgery or an interventional procedure. Central to every IGS system is a software application capable of processing and displaying patient images, registration between multiple coordinate systems, and interfacing with a tool tracking system. We have developed a novel image-guided surgery framework called Kit for Navigation by Image Focused Exploration (KNIFE). This software system serves as the core technology by which a system for reduction of radiation exposure to pediatric patients was developed. The bulk of the initial work in this research endevaour was the development of KNIFE which itself went through countless iterations before arriving at its current state as per the feature requirements established. Secondly, since this work involved the use of captured medical images and their use in an IGS software suite, a brief analysis of the physics behind the images was conducted. Through this aspect of the work, intrinsic parameters (principal point and focal point) of the fluoroscope were quantified using a 3D grid calibration phantom. A second grid phantom was traversed through the fluoroscopic imaging volume of II and flat panel based systems at 2 cm intervals building a scatter field of the volume to demonstrate pincushion and \u27S\u27 distortion in the images. Effects of projection distortion on the images was assessed by measuring the fiducial registration error (FRE) of each point used in two different registration techniques, where both methods utilized ordinary procrustes analysis but the second used a projection matrix built from the fluoroscopes calculated intrinsic parameters. A case study was performed to test whether the projection registration outperforms the rigid transform only. Using the knowledge generated were able to successfully design and complete mock clinical procedures using cardiac phantom models. These mock trials at the beginning of this work used a single point to represent catheter location but this was eventually replaced with a full shape model that offered numerous advantages. At the conclusion of this work a novel protocol for conducting IG ASD procedures was developed. Future work would involve the construction of novel EM tracked tools, phantom models for other vascular diseases and finally clinical integration and use

Systems and Methods for Image Guided Surgery

Systems and methods for image guided surgery are disclosed herein. An example method can include: receiving a plurality of 2D projection images of an object at a plurality of projection angles during a first period of time; and receiving a position of an instrument relative to a tracking coordinate system during the first period of time. The method can also include registering the plurality of 2D projection images relative to the tracking coordinate system to obtain a transformation function that defines a relationship between a coordinate system of the plurality of 2D projection images and the tracking coordinate system; receiving an adjusted position of the instrument relative to the tracking coordinate system during a second period of time that is subsequent to the first period of time; and estimating an adjusted position of the instrument relative to the plurality of 2D projection images using the transformation function

Devices that cooperate with ultrasound probes for muscoskeletal evaluations and related systems and methods

Adaptors for ultrasound probes can have an adaptor body can have an open lower end that allows a distal end of the ultrasound probe to extend therethrough to contact skin of a patient. The adaptor can include a plurality of spaced apart resilient members held by the adaptor body that, in operation, are able to change in length such that the resilient members translate from a first longer length to a second shorter length when the probe applies compressive force to the target tissue

Isolated trochlear shear fracture of the distal humerus: a case report

Laugier was the first to describe an isolated humeral trochlea fracture in 1853. We report the case of a patient with an isolated fracture of the trochlea and discuss the underlying mechanisms and the clinical, radiological features of this pathology and surgical management of this rare fracture. The elbow arthrotomy was done via an anteromedial approach, with the interval through the flexor-pronator muscles medially and the brachialis muscle laterally. The trochlea was temporally fixed by two Kirschner wires, and the definitive fixation was obtained by two cannulated. Herbert screws from anterior to posterior. The elbow was immobilized and splinted in a flexed position (70 degrees) for two weeks to allow soft tissue healing and minimize pain. After cast removal, rehabilitation of elbow was established and actively assisted mobilization for three months. The isolated trochlea fracture is a rare injury and usually, it is associated with other injuries such as elbow dislocation. Few studies in the literature described such fracture and the anteromedial approach; most of these studies described the use of a direct medial approach to the elbow. Several fixation methods were described in the literature, including k-wires, AO compression screws, and headless compression screws. Isolated fracture of the trochlea is rare. The mechanisms causing this fracture are complex; the usual mechanism of isolated trochlear fractures is falling on the palm with the elbow extended and supinated. In our report, the patient disclosed that he felt directly on his flexed elbow. Trochlear fractures require open reduction and internal fixation to achieve anatomical reduction, with excision of the small osteochondral fragments that may be complicated by arthritic changes