Personalized 3D Printed Surgical Tool for Guiding the Chisel during Hump Reduction in Rhinoplasty.

The authors aimed to present an introduction of patient-specific model in rhinoplasty by introducing a 3D printed surgical guide designed and adapted in an individualized manner for guiding dorsal hump reduction. To introduce the tool, we have designed a six step workflow. First, we obtain a digital 3D model of patient anatomy using computed tomography (CT) images. Second, we conduct a surgical preoperative planning of the rhinoplasty on the mentioned model. Third step consists of designing the guide, while taking into account nasal anthropometries and resection objectives. Fourth step is printing the guide and sterilizing it. Fifth step is performing the surgery. The last step is analyzing the main outcomes of the surgery. Our surgical guide allowed us to perform only 1 step osteotomy instead of the usual multistep osteotomy and remove exactly the amount of dorsum that we decided to remove during the preoperative planning. The duration of intervention was considerably shorter than conventional osteotomy. Using the guide was technically easier than the conventional method and reduced the learning curve from years to minutes (once the guide is printed). Moreover, the patient understanding of the procedure was significantly better after showing the 3D model of the surgery. The surgical guide allows a surgeon to transfer with extreme simplicity the presurgical planning to the surgical field. We have to point out that the design of the study does not allow us to quantify predictability, so future studies are needed to demonstrate an accuracy benefit over the former techniques.

Automated annotation removal in agar plates.

Agar plates are widely used in the biomedical field as a medium in which to artificially grow bacteria, algae or fungi. Agar plates (Petri dishes) are used routinely in microbiology laboratories in order to identify the type of micro-organism responsible for infections. Such diagnoses are based on counting the number and type of bacterial colonies growing in the Petri dish. The count of bacterial colonies is a time consuming task prone to human error, so interest in automated counting systems has increased in the recent years. One of the difficulties of automatizing the counting process is the presence of markers and annotations made in the lower part of the agar plate. Efficient removal of such markers can increase the accuracy of the bacterial counting system. This article introduces a fast method for detection, segmentation and removal of annotations in agar plates that improves the results of existing bacterial colony counting algorithms.

Preoperative digital three-dimensional planning for rhinoplasty.

BACKGROUND: This report describes preoperative digital planning for rhinoplasty using a new three-dimensional (3D) radiologic viewer that allows both patients and surgeons to visualize on a common monitor the 3D real aspect of the nose in its inner and outer sides. METHODS: In the period 2002 to 2008, 210 patients underwent rhinoplasty procedures in the authors' clinic. The patients were randomly divided into three groups according to the type of preoperative planning used: photos only, a simulated result by Adobe Photoshop, or the 3D radiologic viewer. The parameters evaluated included the number of patients that underwent surgery after the first consultation, the number of patients who asked for a reintervention, patient satisfaction (according to a test given to the patients 12 months postoperatively), the surgical time required for a functional intervention, and the improvement in nasal function by postoperative rhinomanometry and subjective evaluation. RESULTS: Computer-aided technologies led to a higher number of patients deciding to undergo a rhinoplasty. Simulation of the postoperative results was not as useful in the postoperative period due to the higher number of reintervention requests. CONCLUSION: The patients undergoing rhinoplasties preferred new technologies in the preoperative period. The advantages of using the 3D radiologic viewer included improved preoperative planning, reduction in intraoperative stress, a higher number of patients undergoing surgery, reduction in postoperative surgical corrections, reduction in surgical time for the functional intervention, a higher rate of improvement in nasal function, a higher percentage of postoperative satisfaction, and reduced costs.

Surgical planning and patient-specific biomechanical simulation for tracheal endoprostheses interventions.

We have developed a system for computer-assisted surgical planning of tracheal surgeries. The system allows to plan the intervention based on CT images of the patient, and includes a virtual database of commercially available prostheses. Automatic segmentation of the trachea and apparent pathological structures is obtained using a modified region growing algorithm. A method for automatic adaptation of a finite element mesh allows to build a patient-specific biomechanical model for simulation of the expected performance of the implant under physiological movement (swallowing, sneezing). Laboratory experiments were performed to characterise the tissues present in the trachea, and movement models were obtained from fluoroscopic images of a patient. Results are reported on the planning and biomechanical simulation of two patients that underwent surgery at our hospital.