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Dive into the research topics where Matthias A.W. Merkx is active.

Publication


Featured researches published by Matthias A.W. Merkx.


Journal of Cranio-maxillofacial Surgery | 1994

Condylar resorption after orthognathic surgery. Evaluation of treatment in 8 patients.

Matthias A.W. Merkx; Philip A. van Damme

Several articles have been published on the subject of condylar resorption as a complication of orthognathic surgery. However, since there is little reference to treatment, the frequency of this phenomenon and the results of therapy are evaluated in a retrospective study. 8 patients out of a group of 329 who underwent sagittal split osteotomy in a 10-year period (251 bilateral, 73 Le Fort I + bilateral and 5 unilateral), were treated actively following the development of condylar resorption. 4 patients were operated upon a second time while others underwent occlusal rehabilitation. The results for the patients who underwent revisional surgery were unsatisfactory, with poor aesthetics and occlusal stability. The patients treated with an occlusal splint (+/- orthodontics and/or prosthetic therapy) had a functional occlusion and tolerable temporo-mandibular-joint complaints.


Oral Oncology | 2013

Sentinel node biopsy for squamous cell carcinoma of the oral cavity and oropharynx: A diagnostic meta-analysis

Tim M. Govers; Gerjon Hannink; Matthias A.W. Merkx; Robert P. Takes; Maroeska M. Rovers

BACKGROUND The aim of the study was to systematically assess the accuracy of a sentinel lymph node biopsy (SLNB) in cT1/T2N0 oral cavity and oropharyngeal squamous cell carcinoma patients. METHODS We searched electronic databases, including EMBASE and MEDLINE (Pubmed) up to November 7 2012, by combining oral cancer keywords with sentinel node biopsy keywords. We included diagnostic accuracy studies which used neck dissection as a reference test for the sentinel node biopsy. Study characteristics and measures of accuracy were extracted. Diagnostic accuracy was calculated from 2 × 2 tables. RESULTS 21 Studies (847 patients) could be included. Most of these patients had oral cavity squamous cell carcinoma (OCSCC). The pooled data showed an overall sensitivity of 0.93 [95% CI 0.90-0.95]. Subgroup analysis showed no significant differences in subgroups. CONCLUSION The high sensitivity of SLNB supports a role in the diagnostic work-up of OCSCC.


Oral Oncology | 2008

A prospective study on malnutrition and quality of life in patients with head and neck cancer.

Manon G. A. van den Berg; E.L. Rasmussen-Conrad; Lillian van Nispen; Jaap J. van Binsbergen; Matthias A.W. Merkx

The objective of this observational prospective study in patients with squamous cell carcinoma (SCC) of the oral, oropharyngeal and hypopharyngeal cavity was to look into the relation between malnutrition (>or=10% unintended weight loss within 6 months) and specific quality of life (QoL) parameters longitudinally. Bodyweight and QoL were monitored in 47 patients with SCC at diagnosis, end of treatment and six months after treatment. EORTC QoLQ-C30 and H&N 35 questionnaires were used to assess QoL. Significantly lower scores on the global QoL during treatment (p=0.01) and revalidation (p=0.02) were found for patients who had lost >or=10% compared to patients with <10% loss of weight within 6 month. Patients with radiotherapy and a treatment modality of radiotherapy with surgery or chemotherapy kept their unintended weight loss until the end of treatment. Patients with head and neck cancer treated with radiotherapy are specifically susceptible to malnutrition during treatment with no improvement in body weight or QoL. Professional preventive nutritional support is therefore already required on diagnoses.


British Journal of Nutrition | 2010

Comparison of the effect of individual dietary counselling and of standard nutritional care on weight loss in patients with head and neck cancer undergoing radiotherapy.

Manon G. A. van den Berg; E.L. Rasmussen-Conrad; Koko H. Wei; Heleen Lintz-Luidens; Johannes H.A.M. Kaanders; Matthias A.W. Merkx

Clinical research shows that nutritional intervention is necessary to prevent malnutrition in head and neck cancer patients undergoing radiotherapy. The objective of the present study was to assess the value of individually adjusted counselling by a dietitian compared to standard nutritional care (SC). A prospective study, conducted between 2005 and 2007, compared individual dietary counselling (IDC, optimal energy and protein requirement) to SC by an oncology nurse (standard nutritional counselling). Endpoints were weight loss, BMI and malnutrition (5% weight loss/month) before, during and after the treatment. Thirty-eight patients were included evenly distributed over two groups. A significant decrease in weight loss was found 2 months after the treatment (P = 0.03) for IDC compared with SC. Malnutrition in patients with IDC decreased over time, while malnutrition increased in patients with SC (P = 0.02). Therefore, early and intensive individualised dietary counselling by a dietitian produces clinically relevant effects in terms of decreasing weight loss and malnutrition compared with SC in patients with head and neck cancer undergoing radiotherapy.


Biomaterials | 1999

Incorporation of particulated bone implants in the facial skeleton

Matthias A.W. Merkx; Jaap C. Maltha; Hans-Peter M. Freihofer; Anne Marie Kuijpers-Jagtman

The purpose of this study was to compare the regenerative response of autogenous cortical and cancellous bone chips and a natural particulate resorbable bone mineral (RBM) (Bio-Oss, Geistlich-Pharma, Wolhusen, Switzerland) in standardized bony defects relating paranasal sinuses to one another and to bone blocks. On 13 skeletally mature female goats four standardized critical-sized full thickness bone defects were made in the frontal bone overlying the frontal sinus. These defects were filled at random with cortical bone chips, cancellous bone chips, spongiosa granules of a RBM or left empty. Fluorochrome bone markers were injected subcutaneously 1 and 5 weeks after transplantation, and one week before the animals were killed. The animals were killed at 3, 6, 12 and 24 weeks after surgery. Autogenous cancellous bone chips is the material of choice for bridging a bony defect in the maxillofacial area where there is no need for mechanical strength. They heal in the same way as cancellous bone blocks do. Cortical bone chips are not reliable enough to be used as a solitary bone-grafting material under these conditions. A cortical block as a solitary implant gives better results. RBM granules as solitary implant in a critical-sized defect do not stimulate osteoconduction but give rise to an extensive osteoclastic activity stimulated by the mutual loose relation. A solid block of RBM is in a similar case more reliable.


Biomaterials | 1999

Incorporation of three types of bone block implants in the facial skeleton

Matthias A.W. Merkx; Jaap C. Maltha; Hans-Peter M. Freihofer; Anne Marie Kuijpers-Jagtman

The regenerative response on autogenous cancellous and cortical bone grafts, and on a commercial available xenogenous resorbable bone mineral (RBM) (Bio-Oss, Geistlich-Pharma, Wolhusen, Switzerland) was compared in standardized bony defects related to a paranasal sinus. On 15 skeletally mature goats four critical sized full thickness bone defects were trephined in the frontal bone. These defects were filled at random with a cortical bone plug, a cancellous bone plug, a plug of spongious RBM cut into shape or left empty. Fluorochrome bone markers were injected subcutaneously 1 and 5 weeks after transplantation, and one week before the animals were killed. The animals were killed at 3, 6, 12 and 24 weeks after surgery. Histological evaluation showed that autogenous bone grafts were all accepted and incorporated in a similar way as in calvarial defects. RBM was only osteoconductive. New bone was formed at the margins of the defects, and only little of the RBM was incorporated. Most of the RBM was gradually resorbed by multinucleated osteoclast-like cells.


International Journal of Radiation Oncology Biology Physics | 2009

Malignant tumors of the nasal cavity and paranasal sinuses: long-term outcome and morbidity with emphasis on hypothalamic-pituitary deficiency.

An Snyers; Geert O. Janssens; Marcel Th B Twickler; A.R.M.M. Hermus; Robert P. Takes; Arnoud C. Kappelle; Matthias A.W. Merkx; Piet Dirix; Johannes H.A.M. Kaanders

PURPOSE To evaluate the long-term outcome after surgery and radiotherapy for patients with sinonasal cancer and assess late toxicity, with special emphasis on hypothalamic-pituitary dysfunction. METHODS AND MATERIALS A retrospective analysis of 168 patients treated for sinonasal cancer in a single institute between 1986 and 2006. A more detailed analysis was performed on a subgroup of 76 patients with adenocarcinoma or squamous cell carcinoma treated with curative intent. Long-term survivors were evaluated for late toxicity by a multidisciplinary team using the late effects of normal tissues (LENT SOMA) scoring system. Additional endocrinologic tests were performed for assessment of hypothalamic-pituitary function. RESULTS Five-year actuarial local control and overall survival rates were 62% and 35% for all patients and 64% and 42% for the subgroup with squamous cell carcinoma and adenocarcinoma. In multivariate analysis, T stage was the only significant factor predicting local relapse (79% at 5 years for T1-T3 vs. 53% for T4; p = 0.006). Sinonasal mucosal melanomas had the highest rate of regional failure (33% at 5 years). Thirteen of 21 patients (62%) evaluated at the late morbidity clinic had hormonal disturbances, of whom 5 (24%) had definitive evidence of hypopituitarism with multiple hormonal deficiencies. CONCLUSION Local failure is the dominant cause of treatment failure for patients with sinonasal cancer, with T4 stage the only independent predictor. Because of a high rate of radiation-induced hypopituitarism, we recommend endocrinologic surveillance for these patients.


Clinical Cancer Research | 2004

Intratumoral administration of recombinant human interleukin 12 in head and neck squamous cell carcinoma patients elicits a T-helper 1 profile in the locoregional lymph nodes.

Carla M.L. van Herpen; Maaike W. G. Looman; Marijke Zonneveld; Nicole M. Scharenborg; Peter C.M. de Wilde; Louis van de Locht; Matthias A.W. Merkx; Gosse J. Adema; Pieter H.M. De Mulder

The objective of this Phase II study was to evaluate the pharmacodynamic and immune effects of intratumorally administered recombinant human interleukin-12 (IL-12) on regional lymph nodes, primary tumor, and peripheral blood. Ten previously untreated patients with head and neck squamous cell carcinoma were injected in the primary tumor two to three times, once/week, at two dose levels of 100 or 300 ng/kg, before surgery. We compared these patients with 20 control (non-IL-12-treated) patients. Toxicity was high, with unexpected dose-limiting toxicities at the 300 ng/kg dose level. Dose-dependent plasma IFN-γ and IL-10 increments were detected. These cytokine levels were higher after the first injection than after the subsequent injections. A rapid, transient reduction in lymphocytes, monocytes, and all lymphocyte subsets, especially natural killer cells, was observed, due to a redistribution to the lymph nodes. In the enlarged lymph nodes of the IL-12-treated patients, a higher percentage of natural killer cells and a lower percentage of T-helper cells were found compared with control patients. The same pattern was detected in the infiltrate in the primary tumor. Real-time semiquantitative PCR analysis of peripheral blood mononuclear cells in the peripheral blood showed a transient decrease of T-bet mRNA. Interestingly, the peripheral blood mononuclear cells in the lymph nodes showed a 128-fold (mean) increase of IFN-γ mRNA. A switch from the Th2 to a Th1 profile in the lymph nodes compared with the peripheral blood occurred in the IL-12-treated patients. In conclusion, in previously untreated head and neck squamous cell carcinoma patients, recombinant human IL-12 intratumorally showed dose-limiting toxicities at the dose level of 300 ng/kg and resulted in measurable immunological responses locoregionally at both dose levels.


Laryngoscope | 2006

FDG-PET in the clinically negative neck in oral squamous cell carcinoma.

Bart M. Wensing; Wouter V. Vogel; H.A.M. Marres; Matthias A.W. Merkx; Ernst J. Postema; Wim J.G. Oyen; Frank J. A. van den Hoogen

Objective: With improved diagnostic imaging techniques, it remains difficult to reduce occult metastatic disease in oral squamous cell carcinoma (SCC) to less than 20%. Therefore, supraomohyoid neck dissection (SOHND) still is a valuable staging procedure in these patients.


Head and Neck-journal for The Sciences and Specialties of The Head and Neck | 2014

Nutritional status, food intake, and dysphagia in long-term survivors with head and neck cancer treated with chemoradiotherapy: a cross-sectional study.

Manon G. A. van den Berg; H.J.T. Rutten; E.L. Rasmussen-Conrad; S. Knuijt; Robert P. Takes; Carla M.L. van Herpen; Geert Wanten; Johannes H.A.M. Kaanders; Matthias A.W. Merkx

The aim of this study was to evaluate nutritional status, food intake, and dysphagia in long‐term head and neck cancer survivors.

Collaboration


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H.A.M. Marres

Radboud University Nijmegen

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John A. Jansen

Radboud University Nijmegen

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Robert P. Takes

Radboud University Nijmegen

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J.E.F.M. Frencken

Radboud University Nijmegen Medical Centre

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Manon G. A. van den Berg

Radboud University Nijmegen Medical Centre

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Peter C.M. de Wilde

Radboud University Nijmegen Medical Centre

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Henk Tideman

University of Hong Kong

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