Personalized biomechanical tongue models based on diffusion-weighted MRI and validated using optical tracking of range of motion.

For advanced tongue cancer, the choice between surgery and organ-sparing treatment is often dependent on the expected loss of tongue functionality after treatment. Biomechanical models might assist in this choice by simulating the post-treatment function loss. However, this function loss varies between patients and should, therefore, be predicted for each patient individually. In the present study, the goal was to better predict the postoperative range of motion (ROM) of the tongue by personalizing biomechanical models using diffusion-weighted MRI and constrained spherical deconvolution reconstructions of tongue muscle architecture. Diffusion-weighted MRI scans of ten healthy volunteers were obtained to reconstruct their tongue musculature, which were subsequently registered to a previously described population average or atlas. Using the displacement fields obtained from the registration, the segmented muscle fiber tracks from the atlas were morphed back to create personalized muscle fiber tracks. Finite element models were created from the fiber tracks of the atlas and those of the individual tongues. Via inverse simulation of a protruding, downward, left and right movement, the ROM of the tongue was predicted. This prediction was compared to the ROM measured with a 3D camera. It was demonstrated that biomechanical models with personalized muscles bundles are better in approaching the measured ROM than a generic model. However, to achieve this result a correction factor was needed to compensate for the small magnitude of motion of the model. Future versions of these models may have the potential to improve the estimation of function loss after treatment for advanced tongue cancer.

In-vivo tongue stiffness measured by aspiration: Resting vs general anesthesia.

Tongue cancer treatment often results in impaired speech, swallowing, or mastication. Simulating the effect of treatments can help the patient and the treating physician to understand the effects and impact of the intervention. To simulate deformations of the tongue, identifying accurate mechanical properties of tissue is essential. However, not many succeeded in characterizing in-vivo tongue stiffness. Those who did, measured the tongue At Rest (AR), in which muscle tone subsides even if muscles are not willingly activated. We expected to find an absolute rest state in participants 'under General Anesthesia' (GA). We elaborated on previous work by measuring the mechanical behavior of the in-vivo tongue under aspiration using an improved volume-based method. Using this technique, 5 to 7 measurements were performed on 10 participants both AR and under GA. The obtained Pressure-Shape curves were first analyzed using the initial slope and its variations. Hereafter, an inverse Finite Element Analysis (FEA) was applied to identify the mechanical parameters using the Yeoh, Gent, and Ogden hyperelastic models. The measurements AR provided a mean Young's Modulus of 1638 Pa (min 1035 - max 2019) using the Yeoh constitutive model, which is in line with previous ex-vivo measurements. However, while hoping to find a rest state under GA, the tongue unexpectedly appeared to be approximately 2 to 2.5 times stiffer under GA than AR. Explanations for this were sought by examining drugs administered during GA, blood flow, perfusion, and upper airway reflexes, but neither of these explanations could be confirmed.

Utilization of a 3D printed dental splint for registration during electromagnetically navigated mandibular surgery.

PURPOSE: A dental splint was developed for non-invasive rigid point-based registration in electromagnetically (EM) navigated mandibular surgery. Navigational accuracies of the dental splint were compared with the common approach, that is, using screws as landmarks. METHODS: A dental splint that includes reference registration notches was 3D printed. Different sets of three points were used for rigid point-based registration on a mandibular phantom: notches on the dental splint only, screws on the mandible, contralateral screws (the side of the mandible where the sensor is not fixated) and a combination of screws on the mandible and notches on the dental splint. The accuracy of each registration method was calculated using 45 notches at one side of the mandible and expressed as the target registration error (TRE). RESULTS: Average TREs of 0.83 mm (range 0.7-1.39 mm), 1.28 mm (1.03-1.7 mm), 2.62 mm (1.91-4.0 mm), and 1.34 mm (1.30-1.39 mm) were found, respectively, for point-based registration based on the splint only, screws on the mandible, screws on the contralateral side only, and screws combined with the splint. CONCLUSION: For dentate patients, rigid point-based registration performs best utilizing a dental splint with notches. The dental splint is easy to implement in the surgical, and navigational, workflow, and the notches can be pinpointed and designated on the CT scan with high accuracy. For edentate patients, screws can be used for rigid point-based registration. However, a new design of the screws is recommended to improve the accuracy of designation on the CT scan.

Interactive 3D U-net for the segmentation of the pancreas in computed tomography scans.

The increasing incidence of pancreatic cancer will make it the second deadliest cancer in 2030. Imaging based early diagnosis and image guided treatment are emerging potential solutions. Artificial intelligence (AI) can help provide and improve widespread diagnostic expertise and accurate interventional image interpretation. Accurate segmentation of the pancreas is essential to create annotated data sets to train AI, and for computer assisted interventional guidance. Automated deep learning segmentation performance in pancreas computed tomography (CT) imaging is low due to poor grey value contrast and complex anatomy. A good solution seemed a recent interactive deep learning segmentation framework for brain CT that helped strongly improve initial automated segmentation with minimal user input. This method yielded no satisfactory results for pancreas CT, possibly due to a sub-optimal neural network architecture. We hypothesize that a state-of-the-art U-net neural network architecture is better because it can produce a better initial segmentation and is likely to be extended to work in a similar interactive approach. We implemented the existing interactive method, iFCN, and developed an interactive version of U-net method we call iUnet. The iUnet is fully trained to produce the best possible initial segmentation. In interactive mode it is additionally trained on a partial set of layers on user generated scribbles. We compare initial segmentation performance of iFCN and iUnet on a 100CT dataset using dice similarity coefficient analysis. Secondly, we assessed the performance gain in interactive use with three observers on segmentation quality and time. Average automated baseline performance was 78% (iUnet) versus 72% (FCN). Manual and semi-automatic segmentation performance was: 87% in 15 min. for manual, and 86% in 8 min. for iUNet. We conclude that iUnet provides a better baseline than iFCN and can reach expert manual performance significantly faster than manual segmentation in case of pancreas CT. Our novel iUnet architecture is modality and organ agnostic and can be a potential novel solution for semi-automatic medical imaging segmentation in general.

Quantification of tongue mobility impairment using optical tracking in patients after receiving primary surgery or chemoradiation.

PURPOSE: Tongue mobility has shown to be a clinically interesting parameter on functional results after tongue cancer treatment which can be objectified by measuring the Range Of Motion (ROM). Reliable measurements of ROM would enable us to quantify the severity of functional impairments and use these for shared decision making in treatment choices, rehabilitation of speech and swallowing disturbances after treatment. METHOD: Nineteen healthy participants, eighteen post-chemotherapy patients and seventeen post-surgery patients were asked to perform standardized tongue maneuvers in front of a 3D camera system, which were subsequently tracked and corrected for head and jaw motion. Indicators, such as the left-right tongue range and the deflection angle with the horizontal axis were extracted from the tongue trajectory to serve as a quantitative measure for the impaired tongue mobility. RESULTS: The range and deflection angle showed an excellent intra- and interrater reliability (ICC 0.9) The repeatability experiment showed an average standard deviation of 2.5 mm to 3.5 mm for every movement, except the upward movement. The post-surgery patient group showed a smaller tongue range and higher deflection angle overall than the healthy participants. Post-chemoradiation patients showed less difference in tongue ROM compared with healthy participants. Only a few patients showed asymmetrical movement after treatment, which could not always be explained by T-stage or the side of treatment alone. CONCLUSION: We introduced a reliable and reproducible method for measuring the ROM and to quantify for motion impairments, that was able to show differences in tongue ROM between healthy subjects and patients after chemoradiation or surgery. Future research should focus on measuring patients with oral cancer pre- and post-treatment in combination with the collection of detailed information about the individual tongue anatomy, so that the full ROM trajectory can be used to identify changes over time and to quantify functional impairment.

An interactive surgical simulation tool to assess the consequences of a partial glossectomy on a biomechanical model of the tongue.

Oral cancer surgery has a negative influence on the quality of life (QOL). As a result of the complex physiology involved in oral functions, estimation of surgical effects on functionality remains difficult. We present a user-friendly biomechanical simulation of tongue surgery, including closure with suturing and scar formation, followed by an automated adaptation of a finite element (FE) model to the shape of the tongue. Different configurations of our FE model were evaluated and compared to a well-established FE model. We showed that the post-operative impairment as predicted by our model was qualitatively comparable to a patient case for five different tongue maneuvers.

A new method for three-dimensional evaluation of the cranial shape and the automatic identification of craniosynostosis using 3D stereophotogrammetry.

Craniosynostosis is a congenital defect which can result in abnormal cranial morphology. Three dimensional (3D) stereophotogrammetry is potentially an ideal technique for the evaluation of cranial morphology and diagnosis of craniosynostosis because it is fast and harmless. This study presents a new method for objective characterization of the morphological abnormalities of scaphocephaly and trigonocephaly patients using 3D photographs of patients and healthy controls. Sixty 3D photographs of healthy controls in the age range of 3-6 months were superimposed and scaled. Principal component analysis (PCA) was applied to find the mean cranial shape and the cranial shape variation in this normal population. 3D photographs of 20 scaphocephaly and 20 trigonocephaly patients were analysed by this PCA model to test whether cranial deformities of scaphocephaly and trigonocephaly patients could be objectively identified. PCA was used to find the mean cranial shape and the cranial shape variation in the normal population. The PCA model was able to significantly distinguish scaphocephaly and trigonocephaly patients from the normal population. 3D stereophotogrammetry in combination with the presented method can be used to objectively identify and classify the cranial shape of healthy newborns, scaphocephaly and trigonocephaly patients.

[Wernicke encephalopathy and dry beriberi; late complications after bariatric surgery performed on a patient with a psychiatric history]. / Wernicke-encefalopathie en droge beriberi als late complicaties van bariatrische chirurgie bij patiënte met psychiatrisch belast verleden.

A 38-year-old woman was admitted in a psychiatric hospital because of memory disorders. Dry beriberi and Korsakoff's syndrome, as a late neuropsychiatric manifestation of Wernicke's encephalopathy, were established. The beriberi symptoms decreased slowly, but the patient's memory impairments persisted. These clinical features were caused by a thiamine deficiency. Gastric bypass surgery is associated with an increased risk of thiamine deficiency. Excessive alcohol consumption and poor compliance with vitamin deficiency treatment both contributed to the rapid onset of these disorders. The case we describe demonstrates how important it is that patients who have undergone bariatric surgery are prescribed the correct vitamin supplements and that the treatment is continued for an appropriate period of time; this treatment is particularly important in the case of patients who are also suffering from an comorbid alcohol-related disorder.

Construct failure after open reduction and plate fixation of displaced midshaft clavicular fractures.

INTRODUCTION: Worldwide, implants mostly used for fixation of displaced midshaft clavicular fractures (DMCF) are the easily to bend reconstruction plate and the stiffer small fragment locking compression plate. Construct failure rates after plate fixation of DMCF are reported around 5 percent. Possible risk factors for construct failure are implant type and fracture type. However, little is known about the influence of fracture fixation method on construct failure. The aim of this study was to assess construct failure in plate fixation of DMCF and to identify possible risk factors. METHODS: All consecutive patients treated in a level 1 trauma centre with open reduction and fixation of DMCF using a 3.5-mm reconstruction plate or 3.5-mm small fragment locking compression plate between 2007 and 2015 were evaluated. Potential risk factors for construct failure were analysed using univariate analysis. RESULTS: Two hundred and fifty-nine patients were analysed. Fifty DMCF (19%) were fixated with a reconstruction plate and 209 (81%) with a small fragment locking compression plate. Construct failure was seen in 18 patients (6.9%), including 5 broken plates and 13 with screw loosening. Eight percent of all reconstruction plates broke in contrast to 0.5 percent of all small fragment locking compression plates (p=0.001). All broken implants were used as a bridging plate. Loosening of screws was seen in older patients and when the plate was fixated with less than three bicortical screws on one side of the fracture (p=0.002). CONCLUSIONS: Overall construct failure after open reduction and plate fixation of DMCF occurred in 6.9 percent. Risk factors for plate breakage were the use of a reconstruction plate and a bridging method for fracture fixation. Risk factors for screw loosening were an increasing patient age and plate fixation with less than three bicortical screws on one side of the fracture. RECOMMENDATIONS: Based on the results of this study our recommendation is to use a small fragment locking compression plate for open reduction and internal fixation of DMCF. The surgeon should always strive to fixate the plate on both sides of the fracture with at least three bicortical screws.

Feasibility of automated target centralization in colonoscopy.

PURPOSE: Early detection of colorectal cancer is key to full recovery. This urged governments to start population screening programs for colorectal cancer, often using flexible endoscopes. Flexible endoscopy is difficult to learn and time-consuming. Automation of flexible endoscopes may increase the capacity for the screening programs. The goal of this pilot study is to investigate the clinical and technical feasibility of an assisting automated navigation algorithm for a colonoscopy procedure. METHODS: Automated navigation (lumen centralization) was implemented in a robotized system designed for conventional flexible endoscopes. Ten novice and eight expert users were asked to perform a diagnostic colonoscopy on a colon model twice: once using the conventional and once using the robotic system. Feasibility was evaluated using time and location data as measures of the system's added value. RESULTS: Automated target centralization (ATC) was turned on by the novices for a median of 4.2% of the time during insertion and 0.3% during retraction. Experts turned ATC on for 4.0% of the time during insertion and 11.6% during retraction. Novices and experts showed comparable times to reach the cecum with the conventional or the robotic setup with ATC. CONCLUSION: The ATC algorithm combined with the robotized endoscope setup works in an experimental setup that closely resembles the clinical environment and is considered feasible, although ATC use was lower than expected. For novices, it was unclear whether the low usage was due to unfamiliarity with the system or because they did not need ATC. Experts used ATC also during the retraction phase of the procedure. This was an unexpected finding and may indicate an added value of the system.

Technical errors and complications in orthopaedic trauma surgery.

INTRODUCTION: Adverse events and associated morbidity and subsequent costs receive increasing attention in clinical practice and research. As opposed to complications, errors are not described or analysed in literature on fracture surgery. The aim of this study was to provide a description of errors and complications in relation to fracture surgery, as well as the circumstances in which they occur, for example urgency, type of surgeon, and type of fracture. METHODS: All errors and complications were recorded prospectively in our hospital's complication registry, which forms an integral part of the electronic medical patient file. All recorded errors and complications in the complication registry linked to fracture surgery between 1 January, 2000 and 31 December, 2010 were analysed. RESULTS: During the study period 4310 osteosynthesis procedures were performed. In 78 (1.8 %) procedures an error in osteosynthesis was registered. The number of procedures in which an error occurred was significantly lower (OR = 0.53; p = 0.007) when an orthopaedic trauma surgeon was part of the operating team. Of all 3758 patients who were admitted to the surgical ward for osteosynthesis, 745 (19.8 %) had one or more postoperative complications registered. There was no significant difference in the number of postoperative complications after osteosynthesis procedures in which an orthopaedic trauma surgeon was present or absent (16.7 vs. 19.1 %; p = 0.088; OR 0.85). DISCUSSION: In the present study the true error rate after osteosynthesis may have been higher than the rate found. Errors that had no significant consequence may be especially susceptible to underreporting. CONCLUSION: The present study suggests that an osteosynthesis procedure performed by or actively assisted by an orthopaedic trauma surgeon decreases the probability of an error in osteosynthesis. Apart from errors in osteosynthesis, the involvement of an orthopaedic trauma surgeon did not lead to a significant reduction in the number of postoperative complications.

[Mechanisms of catatonia]. / Mechanismen van katatonie.

BACKGROUND: Catatonia is being increasingly viewed as a unique syndrome consisting of specific motor signs that respond characteristically and uniformly to benzodiazepines and electroconvulsive therapy. This interpretation is also reflected in changes in the classification of catatonia in DSM-5. An all-embracing pathogenesis of catatonia remains elusive. AIM: To review the mechanisms of catatonia. METHOD: We reviewed the literature. RESULTS: Certain aspects of catatonia can be explained by a number of different mechanisms. We present a new, more comprehensive model involving the vagal nerve. CONCLUSION: Further research into the underlying mechanisms of catatonia is needed in order to to find new therapies.

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.

Burnout, engagement and resident physicians' self-reported errors.

Burnout is a work-related syndrome that may negatively affect more than just the resident physician. On the other hand, engagement has been shown to protect employees; it may also positively affect the patient care that the residents provide. Little is known about the relationship between residents' self-reported errors and burnout and engagement. In our national study that included all residents and physicians in The Netherlands, 2115 questionnaires were returned (response rate 41.1%). The residents reported on burnout (Maslach Burnout Inventory-Health and Social Services), engagement (Utrecht Work Engagement Scale) and self-assessed patient care practices (six items, two factors: errors in action/judgment, errors due to lack of time). Ninety-four percent of the residents reported making one or more mistake without negative consequences for the patient during their training. Seventy-one percent reported performing procedures for which they did not feel properly trained. More than half (56%) of the residents stated they had made a mistake with a negative consequence. Seventy-six percent felt they had fallen short in the quality of care they provided on at least one occasion. Men reported more errors in action/judgment than women. Significant effects of specialty and clinical setting were found on both types of errors. Residents with burnout reported significantly more errors (p < 0.001). Highly engaged residents reported fewer errors (p

Catatonia: disappeared or under-diagnosed?

BACKGROUND: Over the last century, especially during the latter half, the prevalence of the diagnosis of catatonic schizophrenia decreased considerably. Several explanations for this phenomenon have been put forward. SAMPLING AND METHODS: The present study investigated the frequency of the diagnosis of catatonic schizophrenia in a large sample of admitted psychiatric patients (n = 19,309). In addition, the presence of catatonic symptoms was studied in a sample of patients with schizophrenia (n = 701) and in a group of consecutively admitted psychotic patients (n = 139). In these two groups the effect of the diagnostic procedures on the recognition of catatonia was examined. RESULTS: The diagnosis of catatonic schizophrenia dropped from 7.8% in 1980-1989 to 1.3% in 1990-2001 (p < 0.001). In addition, a possible under-diagnosis of catatonic schizophrenia was found in an independent sample of patients with schizophrenia. Application of a systematic catatonia rating scale in patients admitted with acute psychosis identified a bimodally distributed catatonic dimension. At least 18% of these patients fulfilled the criteria for catatonia. Interestingly, the catatonic subgroup used atypical antipsychotic compounds more frequently (p < 0.05). CONCLUSIONS: The results suggest that changes in diagnostic criteria and the diagnostic procedure itself are responsible for the under-recognition of catatonia.

Treatment of unstable trochanteric fractures. Randomised comparison of the gamma nail and the proximal femoral nail.

The proximal femoral nail (PFN) is a recently introduced intramedullary system, designed to improve treatment of unstable trochanteric fractures of the hip. In a multicentre prospective clinical study, the intra-operative use, complications and outcome of treatment using the PFN (n = 211) were compared with those using the gamma nail (GN) (n = 213). The intra-operative blood loss was lower with the PFN (220 ml v 287 ml, p = 0.001). Post-operatively, more lateral protrusion of the hip screws of the PFN (7.6%) was documented, compared with the gamma nail (1.6%, p = 0.02). Most local complications were related to suboptimal reduction of the fracture and/or positioning of the implant. Functional outcome and consolidation were equal for both implants. Generally, the results of treatment of unstable trochanteric fractures were comparable for the PFN and GN. The pitfalls and complications were similar, and mainly surgeon- or fracture-related, rather than implant-related.

Impact of ultrasonographic duplex scanning on therapeutic decision making in lower-limb arterial disease.

Ultrasonographic duplex scanning has become a valuable diagnostic technique in detecting and grading stenoses and occlusions of the aortoiliac and femoropopliteal arteries. However, the question remains as to whether a treatment strategy can be designed without diagnostic angiography. This prospective study evaluated the impact of duplex scanning on therapeutic decision making. Patients with intermittent claudication, rest pain or ischaemic ulceration of the lower limb who were eligible for invasive treatment were studied. If treatment was considered necessary, a duplex scan was performed instead of diagnostic angiography. The surgeon made a therapeutic decision based on clinical assessment and information obtained from the duplex scan. If it was felt that duplex scanning gave insufficient information, diagnostic angiography was then performed. A group of 112 consecutive patients were studied prospectively; 12 were excluded for logistical reasons. The 100 remaining patients (intermittent claudication in 69, rest pain in 16, ischaemic ulceration in 15) were evaluated. Based on non-invasive tests 22 patients were treated conservatively, 36 were scheduled for percutaneous transluminal angioplasty (PTA) and 32 were scheduled for surgery. Angiography was requested to determine the definitive treatment policy in 28 patients: four of the 22 were scheduled for conservative treatment and 24 of the 32 were scheduled for surgery. All PTAs were performed without prior diagnostic angiography. Angiography was considered necessary in a further ten patients to formulate a therapeutic strategy. In 62 patients the treatment strategy could be determined without diagnostic angiography. Twenty-three of the 39 angiograms performed did not give additional information on treatment strategy. Integrated use of duplex scanning for the investigation of patients with arterial occlusive disease of the lower limb can reduce the need for diagnostic angiography.

The results of denatured homologous vein grafts as conduits for secondary haemodialysis access surgery.

OBJECTIVES: To determine the value of denatured homologous vein grafts as a conduit for secondary haemodialysis access. DESIGN: Retrospective clinical study. SETTING: 2 University Hospitals. MATERIALS AND METHODS: One-hundred-and-twenty-five patients received 195 grafts over a period of five years. Fifty-six first grafts (45%) functioned without complications throughout the study period of 5.8 years. MAIN RESULTS: Primary patency was 57% after 1 year and 25% after 3 years of follow-up. Of the initial grafts, 69 (55%) needed 161 interventions, for thrombosis (n = 59), stenosis (n = 43), failure beyond repair (n = 40), aneurysm (n = 12), infection (n = 4), steal syndrome (n = 1), and other causes (n = 2). Secondary patency was 76% at 1 year and 52% at 3 years of follow-up. A major advantage of these grafts was the low rate (2.6%) of infection. Aneurysm formation occurred 17 times in 195 grafts (8.7%). CONCLUSIONS: Denatured homologous vein graft is a good alternative in secondary access surgery.