Predictive model for functional consequences of oral cavity tumour

The prediction of functional consequences after treatment of large oral cavity tumours is mainly based on the size and location of the tumour. However, patient specific factors play an important role in the functional outcome, making the current predictions unreliable and subjective. An objective prediction is necessary for better patient oriented care, where the choice between surgery or chemo- and radiotherapy could be made according to more reliable measures. In this project, work is being performed to create a tool to obtain this objective prediction. The aim is to develop a virtual biomechanical patient-specific model of the oral cavity for virtual surgery. By adjusting the model, so as to mimic the performed surgery, an accurate preoperative assessment of the postoperative functional consequences can be made for each individual patient

Improving hands-free speech rehabilitation in laryngectomized patients – proof-of-concept of a novel intratracheal fixation device

Permanent hands-free speech with the use of an automatic speaking valve (ASV) is regarded as the optimal voice rehabilitation after total laryngectomy. Due to fixation problems, regular ASV use in patients with a laryngectomy is limited. We have developed an intratracheal fixation device (ITFD) composed of an intratracheal button augmented by hydrophilic foam around its shaft. This study evaluates the short-term effectiveness and experienced comfort of this ITFD during hands-free speech in 7 participants with a laryngectomy. We found that 4 of 7 participants had secure ASV fixation inside the tracheostoma during hands-free speech for at least 30 minutes with the ITFD. The ITFD’s comfort was perceived positively overall. The insertion was perceived as being mildly uncomfortable but not painful. This proof-of-concept study demonstrates the feasibility of the ITFD that might improve stomal attachment of ASVs, and it provides the basis for further development toward a prototype suitable for long-term daily use

Predicting 3D lip shapes using facial surface EMG

Aim The aim of this study is to prove that facial surface electromyography (sEMG) conveys sufficient information to predict 3D lip shapes. High sEMG predictive accuracy implies we could train a neural control model for activation of biomechanical models by simultaneously recording sEMG signals and their associated motions. Materials and methods With a stereo camera set-up, we recorded 3D lip shapes and simultaneously performed sEMG measurements of the facial muscles, applying principal component analysis (PCA) and a modified general regression neural network (GRNN) to link the sEMG measurements to 3D lip shapes. To test reproducibility, we conducted our experiment on five volunteers, evaluating several sEMG features and window lengths in unipolar and bipolar configurations in search of the optimal settings for facial sEMG. Conclusions The errors of the two methods were comparable. We managed to predict 3D lip shapes with a mean accuracy of 2.76 mm when using the PCA method and 2.78 mm when using modified GRNN. Whereas performance improved with shorter window lengths, feature type and configuration had little influence

Towards virtual surgery in oral cancer to predict postoperative oral functions preoperatively

Our aim was to develop a dynamic virtual model of the oral cavity and oropharynx so that we could incorporate patient-specific factors into the prediction of functional loss after advanced resections for oral cancer. After a virtual resection, functional consequences can be assessed, and a more substantiated decision about treatment can be made. In this study we used a finite element model of the tongue, which can be implemented in the total virtual environment in the future. We analysed the movements and changes in volume, and the effects of changes in the material variables, to mimic scar tissue. The observed movements were in accordance with descriptions of in vivo movements. Affected movements caused by the mimicked scar tissue were also similar to expectations. Some changes in volume were measured, particularly in individual elements. We have taken the first steps in the development of a finite element model of the tongue. Now, refinement is necessary to make the model suitable for future use in virtual surgery