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.

Oral function after maxillectomy and reconstruction with an obturator.

Maxillectomy defects can be reconstructed by a prosthetic obturator or (free) flap transfer, but there is no consensus about the optimal method. This study evaluated 32 maxillectomy patients with prosthetic obturation regarding function (mastication, subjective oral and swallowing complaints and maximal mouth opening). Outcomes were related to the extent of the resection (Brown maxillectomy classification), dentition and history of adjuvant radiotherapy. Maxillectomy defects ranged from 2-1 to 4B on the Brown classification, and most had a defect graded as 2-A or 2-B. Mean mixing ability test after 10 chewing strokes was 24.2 and after 20 chewing strokes 19.7, which compares to edentulous healthy individuals. None of the outcomes was influenced by Brown classification. Radiotherapy negatively influenced mean maximal mouth opening (29.1mm versus 40.9 mm, p=0.017) and subjective outcomes. Edentate obturated patients had worse outcomes than dentate patients, measured by mixing ability test and questionnaire. In conclusion, mastication after obturator reconstruction of a maxillectomy defect is comparable to mastication with full dentures. Size of the maxillectomy defect did not significantly influence functional outcome, but adjuvant radiotherapy resulted in worse mouth opening and self-reported oral and swallowing problems. Residual dentition had a positive influence on mastication and subjective outcomes.

The surgical dilemma of 'functional inoperability' in oral and oropharyngeal cancer: current consensus on operability with regard to functional results.

OBJECTIVES: If surgical resection of a tumour results in an unacceptable loss of function, this is defined as 'functional inoperability'. The current survey aims to define the borders of functional inoperability in oral and oropharyngeal carcinoma and evaluate its current use by obtaining opinions from the experts in the field. DESIGN: A web base survey. PARTICIPANTS: Dutch head-neck surgeons and radiotherapists. MAIN OUTCOME MEASURES: Assessment of functional results after tumour resection in twenty-two statements and five cases. RESULTS: Response on the survey is 93% and the reactions are variable. Reactions vary slightly by the size of the clinic or discipline (radiation oncology versus head and neck surgery). There is agreement about the unacceptable function loss after total glossectomy. There is no absolute consensus about the functional outcome after certain surgical procedures, namely: bilateral maxillectomy, resection of a tonsil and resection of base of tongue carcinoma including removal of the vallecula and epiglottis, and total soft palate resection. Disagreement of operability is also observed for T3 and T4 base of tongue carcinomas based on case descriptions and Magnetic Resonance Images. Assessment of whether one hypoglossal nerve can be preserved is agreed to be a key factor for functional operability. CONCLUSIONS: The term functional inoperability appears to be clinically used by Dutch experts in the decision making process in advanced head and neck carcinomas. According to the experts who took part in the survey, primary total glossectomy or sacrificing both hypoglossal nerves is an operation that causes too much and therefore unacceptable function loss. In several case scenarios a consensus over operability could not be reached by the experts. The decision varies per physician, institute and patient. Functional inoperability is variable and difficult to determine, but it is clinically used and therefore important to bring under attention.

Stent repair of an anastomotic pseudoaneurysm of the carotid artery after free fibula transplantation.

We describe an anastomotic pseudoaneurysm of the carotid artery as a complication after free fibular transplantation. The treatment of choice was endovascular placement of a stent, although this could have occluded the arterial supply to the graft. In our case, the graft remained vital.

Intraparotid facial nerve schwannoma. What to do?

An intraparotid facial nerve schwannoma is often not recognised in pre-treatment work-up and frequently results in subsequent significant postoperative morbidity. We have evaluated the literature regarding pre-treatment work-up and facial nerve function outcome. Two of our own cases are presented. A minority of the intraparotid schwannomas can be removed by resection while preserving facial nerve integrity and function. In the event of preoperative facial nerve dysfunction, tumour resection and subsequent nerve repair should be considered. If resection of an intraparotid facial nerve schwannoma cannot be performed with preservation of facial nerve integrity and function, a wait-and-see policy seems justified due to the indolent behaviour of the tumour and moderate results of facial nerve reconstruction.

Identification of differentially regulated genes in mildly hyperlipidemic ApoE3-Leiden mice by use of serial analysis of gene expression.

Although genes determining lipoprotein homeostasis and atherosclerosis are the subject of intensive investigation, only a subset of these genes is known at present. Hence, we do not have sufficient knowledge to explain the genetic basis of hyperlipidemia in the majority of subjects. Our aim was to identify novel genes and pathways underlying lipoprotein homeostasis by using serial analysis of gene expression. The liver expression profile of mild hyperlipidemic apolipoprotein E3-Leiden (E3L) transgenic mice was compared with that of the wild-type C57BL/6JIco (B6) mice. Over 18 000 liver transcripts of B6 as well as E3L mice were analyzed, representing >9400 unique genes. One hundred seventy-five genes showed altered expression between the strains (P<0.05). Although several of these genes belonged to known metabolic pathways, such as lipoprotein metabolism, detoxification processes, glycolysis, and the acute-phase response, most were novel. Differential gene expression of 8 of 10 genes tested could be confirmed by Northern blot analysis. This inventory of differentially expressed genes will provide a unique basis for detailed studies to gain more insight into their role in lipoprotein homeostasis and atherosclerosis.

Different effects of conjugated linoleic acid isomers on lipoprotein lipase activity in 3T3-L1 adipocytes.

Conjugated linoleic acids (CLAs) are the positional and geometric isomers of linoleic acid. In the present study the effects of cis-9, trans-11 CLA (c9,t11 CLA) and trans-10, cis-12 CLA (t10,c12 CLA ) on intracellular and heparin-releasable (HR-) lipoprotein lipase (LPL) activity in 3T3-L1 adipocytes were investigated. Cells were exposed to the two CLA isomers and linoleic acid, which were bound to bovine serum albumin (BSA). In the adipocytes insulin up-regulated and tumor necrosis factor alpha (TNFalpha) down-regulated HR-LPL activity, which corresponds with the findings in vivo. The experimental fatty acids at low concentrations (<30 µmol/L) moderately increased intracellular and HR-LPL activity. At a concentration of 100 µmol/L, c9,t11 CLA and t10,c12 CLA suppressed HR-LPL activity to 20 and 24% below the BSA control level, respectively, while linoleic acid had no effect unless its concentration was as high as 1000 µmol/L. Insulin abolished the inhibitory effect of c9,t11 CLA, but not of t10,c12 CLA. In the presence of insulin, t10,c12 CLA inhibited HR-LPL activity by 41% compared to BSA control. In contrast to TNFalpha, which suppressed both intracellular LPL and HR-LPL activity, CLAs suppressed HR-LPL activity without decreasing intracellular LPL activity. Additionally, t10,c12 CLA (100 µmol/L) partially prevented TNFalpha-induced decrease of intracellular LPL activity. These results indicate that CLAs differ from linoleic acid in regulating HR-LPL activity, and t10,c12 CLA appeared to be more effective than c9,t11 CLA.