PubMed Health⌕ Search

Biomedical subjects

R Koole

Publications and source records attributed to R Koole.

At least 19 recordsLinked to original sources
PubMed2006

Professional delay in head and neck cancer patients: analysis of the diagnostic pathway.

The aim of this study was to identify which factors are related to specialist delay and to determine the length of the diagnostic pathway in head and neck cancer patients. Three hundred and six patients with a carcinoma of the larynx, pharynx or oral cavity were included in the study. Logistic regression analysis was used to identify risk factors for specialist delay. Large (T3-T4) tumors showed significantly less specialist delay than small (T1-T2) tumors (p=0.045, odds ratio [OR]=0.6). Pharyngeal (p=0.00, OR=0.2) and oral carcinomas (p=0.00, OR=0.2) had less specialist delay than glottic carcinomas. Hoarseness was associated with prolonged specialist delay (p=0.00, OR=5.9). Heavy drinking in combination with smoking (p=0.005, OR=0.3), a sore throat (p=0.02, OR=0.4) or having a lesion (p=0.03, OR=0.2) showed a shorter diagnostic period. The duration of the diagnostic process in a general hospital ranged from 0 to 570 days, with a median of 14 days. Only a small group of patients met the ideal management standards in our head and neck clinic. Although prolonged delay was associated with small (glottic) tumors, the diagnostic process takes a fairly long time. The results indicate that continued educational programs for professionals are warranted.

Adolescent↗
PubMed2006

Functional results after conservative treatment of fractures of the mandibular condyle.

Since the introduction of osteosynthesis materials for rigid internal fixation after anatomical reduction there is an ongoing discussion about the treatment of condylar fractures of the mandible. Sixty patient files were analyzed and 28 patients were seen for re-examination and a x-orthopantomogram was taken. Functionality was graded with the Helkimo index at an average of 3.0 years follow-up. The clinical dysfunction index showed: severe symptoms in 11%, moderate symptoms in 39%, mild symptoms in 39% and 11% had no symptoms. Index for occlusal state showed: 21% severe occusal disturbances, 61% moderate occlusal disturbances and 18% no occlusal disturbances. According to the anamnestic dysfunction index 89% of the patients were symptom-free. The clinical outcome group showed a significant left/right ramus length difference compared with a 20-person control group. The re-examined group did not significantly differ from the control group. Conservative treatment for condylar fractures was successful in only 46% according to the 1999 consensus criteria described by Bos et al.

Adolescent↗
PubMed2005

Guidelines in head and neck oncology compliance and consequences of deviations from the standard protocol for tongue and floor of mouth squamous carcinoma.

OBJECTIVES: To investigate the extent of violation of a regional guideline for the treatment of patients with carcinoma of the tongue/floor of mouth (ICD0 C02, C04). Different aspects of protocol violation (i.e. undertreatment or overtreatment) and consequences for treatment outcome were evaluated. DESIGN: Retrospective analysis of data from medical records. SETTING: The Department of Maxillofacial and Oral Surgery and the Department of Otorhinolaryngology and Head and Neck Surgery of the University Medical Centre Utrecht. PARTICIPANTS: A total of 217 patients treated between 1991 and 2001 for a stage II and stage III carcinoma of the tongue/floor of mouth. MAIN OUTCOME MEASURES: Protocol violation, tumour recurrence. RESULTS: The overall adherence to the guideline was 55%. In the non-adherence group of patients, 21% were overtreated, 71% were undertreated, and 8% were both overtreated and undertreated. There was no statistically significant difference in tumour recurrence between the two groups for stage II (P=0.68) or stage III (P=0.97) disease, or between undertreatment and overtreatment of patients with stage II (P=0.47) or stage III (P=0.90) disease. CONCLUSIONS: Although protocol violation occurs in as many as 45% of patients, this does not result in a worse tumour recurrence. Neither overtreatment nor undertreatment appears to affect the overall tumour recurrence.

Female↗
PubMed2005

The influence of orthognathic surgery on masticatory performance in retrognathic patients.

Surgical correction of retrognathism may influence chewing performance and its underlying mechanisms selection and breakage of food particles. In this study we examined the hypothesis that treatment of this anomaly improves chewing performance. Furthermore, we determined to what extent this change can be attributed to selection and breakage of food particles. Eleven patients were tested before and 1-1.5 years after surgery. To determine chewing performance, eight cubes of 8 mm of a silicone rubber (Optosil) were used as a test food. Selection and breakage were determined in one-chew experiments using three particle sizes. On average, no differences were found for chewing performance, selection or breakage. However, on an individual basis, patients with a poor chewing performance before surgery tended to improve, whereas no improvement was observed for patients with a good chewing performance. The change in chewing performance was mainly due to a change in breakage of the food particles.

Adult↗
PubMed2004

Anterior tooth replacement with implants in grafted alveolar cleft sites: a case series.

When a residual edentulous space in the anterior region remains after surgical and orthodontic treatment of alveolar cleft patients, implant placement with or without additional grafting is a treatment option. We placed a total of 10 implants in nine consecutive alveolar cleft patients (five females, four males) with residual anterior edentulous spaces and non-restored neighbouring teeth. Patient age generally varied from 18 to 22 years. Additional (tertiary) bone grafting, implant placement after 3 months of graft consolidation and implant uncover after no less than 6 months was the favoured surgical protocol in the five most recent cases. Ample time was allowed to evaluate and guide the development of soft tissues, following second-stage surgery. For this purpose, temporary crowns were fabricated, adjusted and left in place for over 3-4 months in seven out of nine cases. No implants were lost after a mean observation period of 3.4 years and all implants function without objective (radiographic) or subjective problems. Aesthetics were considered acceptable in seven out of nine cases. Unsatisfactory aesthetic results originated from poor implant positioning or alignment in two patients who did not undergo tertiary bone grafting. We conclude that implant placement in alveolar cleft sites is a comprehensive but viable treatment option. Tertiary grafting of the site is recommended to achieve better ridge contour and bone height. This allows optimal implant placement and alignment.

Adolescent↗
PubMed2004

[Complications during and after dentoalveolar surgery].

In dentistry complications are undesirable adventures provoked by oral health care delivery. If there is any risk of a complication, the patient needs to be informed before treatment. Occurrence of complications can be minimized by adequate diagnostics and planning sufficient time for treatment. The most common complications during and after dentoalveolar surgery are discussed, such as complications during or after producing local anaesthesia, nerve injuries, complications during or after tooth extraction, aspiration, jaw luxation, disturbed wound healing, and complications during or after implantation procedures.

Alveolar Process↗
PubMed2003

[Oral surgery in hemophilia patients].

Oral surgery in hemophilia patients requires special arrangements in close collaboration with a hemotologist. Minor oral surgeries in not complicated cases can be done by a dentist or an oral surgeon with aid and assistance of a hemotologist. All major oral surgeries in hemophilia patients with antibodies counteracting coagulation agents should occur in a hemophilia treatment centre.

Adult↗
PubMed2002

[Rising incidence of invasive (T4) head-neck carcinoma at the Utrecht University Medical Center, 1980-1998].

OBJECTIVE: To determine whether there is an increase in the incidence of diagnosed head and neck tumours at an advanced stage (T4). DESIGN: Secondary data-analysis. METHOD: Data of patients registered in 1980-1998 at the Utrecht University Medical Centre, the Netherlands, were analysed for the relative prevalence of T4 tumours in the oral cavity, pharynx and larynx on the basis of sex, age and tobacco and alcohol usage. The results were compared with figures from the Dutch national cancer registry (1989-1997). RESULTS: Data were collected for 2993 patents (2256 men and 737 women; average age 63 years (SD 12)). Of these 35 had a carcinoma situated on the lips, 1091 in the oral cavity, 1321 in the larynx and 546 in the pharynx. There was an increase in T4 tumours of 12.2% (43/353) of all tumours in 1980-1984 to 27.2% (252/1033) in 1995-1998. Linear regression analysis estimated an increase of 0.9% every year. Selected referral to the Utrecht University Medical Centre was unlikely because the increased incidence of T4 tumours could be recognised in the national cancer registry. There was no change in the sex distribution over the study period. The increase in the 40 to 50-year-old age group was greater than that of the patients aged 80 years and over. T4 tumours were more prevalent than T1 tumours in patients who had smoked 20 or more cigarettes per day or drank more than 4 units of alcohol per day. CONCLUSION: The percentage of cancer patients presenting with an advanced stage (T4) of head-neck tumours increased during the study period.

Adult↗
PubMed2002

[Repair and revision 9. Peripheral trigeminal nerve injury].

A review is given about long-term incidence of sensory disturbance in the areas of innervation of the n. trigeminus for different types of trauma and/or treatment. Diagnosis, clinical course and possible types of treatment are in addition reviewed. Regarding diagnosis, the outcome of a test on sensory function is not always related to the degree of nerve damage because methods differ in the type of afferent nerve fibers of which function is tested, and some specificity might occur in nerve damage, i.e. either thick or thin afferent fibers might be predominantly affected at a particular time. An initial quick testing of sensory function is recommended. This testing includes examining two sensory modalities, which are related to functioning of thick and thin afferent fibers respectively and which have a dichotomous yes/no outcome on the incidence of a pronounced sensory disturbance.

Humans↗
PubMed2002

[Onlay grafts in combination with endosseous implants in severe mandibular atrophy. A prospective radiological study].

The placement of endosseous implants in combination with iliac crest onlay grafting of the anterior mandible is one of the treatment modalities for extreme atrophy of the mandible. The remodelling of these onlay grafts was studied using standardized extraoral oblique lateral cephalometric radiographs (OLCRs). A group of 8 patients was used in this prospective study. The measurements obtained from the OLCRs indicated the existence of the following stages in the process of remodelling of the bone grafts: 1. decrease in thickness and radiographic density of the (upper) cortex of the graft, predominantly during the first half year after grafting; 2. no significant changes in the radiographic density of the upper spongeous part of the graft; 3. a mean decrease of approximately 25% in the overall thickness of the graft, particularly during the first half year; and 4. an increase in the radiographic density of the lower part of the spongeous bone in the second half year after grafting. It is concluded that the remodelling of the graft has a predictable pattern in time. Densitometric measurement using standardized OLCRs can be a useful tool to evaluate quantitative changes of bone grafts to the mandible. The treatment described can be used on very strict indications only.

Absorptiometry, Photon↗
PubMed2001

Improved prediction of metastasis in tongue carcinomas, combining vascular and nuclear tumor parameters.

BACKGROUND: Predicting the presence of metastasis, based on tumor or tumor-related characteristics is of utmost importance. The authors studied the significance of tumor DNA features and tumor-related angiogenesis to predict the occurrence of metastasis in squamous cell carcinomas (SCCs) of the tongue. METHODS: Paraplast blocks from resection specimens of 20 metastasized and 20 nonmetastasized SCCs of the tongue with a minimum follow-up of 24 months were used. Tissue sections were stained with anti-CD34 monoclonal antibodies for vessel visualization, and according to Feulgen to stain DNA. Using image analysis, data from both stainings were computed for each of the 40 carcinomas. A logistic regression model to predict the presence of metastasis, based on vascular and nuclear morphology features, was developed. RESULTS: The intratumor variation of chromatin condensation and the percentage vessels smaller than 5 microm in diameter were selected for the model. The model correctly predicted metastasis in 90% of patients and excluded metastasis correctly in 75% of nonmetastasized tumors. Taking into account the prevalence of metastasis in SCC of the tongue of between 30% and 60%, this means a predictive value for a negative outcome of between 95% and 83%. CONCLUSIONS: The proposed model shows an improvement of predictive values compared with previous models with single parameters. Therefore, a multiparameter model appears to predict the multiparameter process of metastasis better.

Carcinoma, Squamous Cell↗
PubMed2001

The use of the transmandibular implant system in extreme atrophy of the mandible; a retrospective study of the results in two different hospital situations.

This retrospective study aims to investigate and compare the results obtained with the transmandibular implant (TMI) in two different hospital situations. Group I were patients treated in a teaching hospital since 1984 by a varying group of surgeons and prosthodontists with a varying degree of experience with the TMI. Group II were patients treated in 1993 and 1994 by experienced surgeons and prosthodontists in the hospital where the TMI was originally developed. In group I, a relatively high frequency of reversible (45.4%) and irreversible--i.e. implant loss--(15.2%) complications occurred. In group II, no implants were lost and reversible complications were reported in 10.8% of the patients. In general, the patients of both groups were quite satisfied with the result of the treatment. In both groups, limited bone loss around the implant posts could be observed. An increase in the height of the mandibular bone distal of the lateral posts was frequently observed, especially in group II. It is concluded that both very favourable and less favourable results can be obtained with the TMI. In this study the best results are found in a highly specialized TMI centre, where patients are treated--with only uncompromised implant-posts--by a small group of experienced surgeons and prosthodontics with accurate application of the existing guidelines.

Atrophy↗
PubMed2001

Intra-arterial embolization of head-and-neck cancer with radioactive holmium-166 poly(L-lactic acid) microspheres: an experimental study in rabbits.

A total of 22 NZW rabbits with VX2 squamous cell carcinomas transplanted into the auricles were intra-arterially (i.a.) embolized with radioactive or inactive holmium-labelled poly(L-lactic acid) (HoPLA) microspheres with a mean diameter of 38-80 microm. The effects on tumour growth, the efficiency of i.a. infusion, the efficacy of retention of microspheres in the primary tumour and the excretion of free holmium-166 were analyzed. Complete tumour remissions were obtained in 79% and 86% following embolization with radioactive and inactive microspheres, respectively. Over 95% of the microspheres were retained in the tumour and the leaching of holmium-166 in urine and faeces was less than 0.1% in 2 days. The injection efficiency was not optimal, as 40% of the microspheres were retained in the cannulation system. Arterio-arteriolar connections should be detected and closed prior to embolization to prevent stray emboli from entering the brain. It is concluded that 166HoPLA microspheres are promising candidates for further studies on radio-embolization of unresectable head-and-neck cancer.

Animals↗
PubMed2001

Tumour embolization of the Vx2 rabbit head and neck cancer model with Dextran hydrogel and Holmium-poly(L-lactic acid) microspheres: a radionuclide and histological pilot study.

INTRODUCTION: Intra-arterial embolization of unresectable malignant tumours with biodegradable microspheres is an effective way of selective anti-tumour therapy. Promising candidates are Dextran hydrogel (Dex) microspheres for chemo-embolization and Holmium-166 poly(L-lactic acid) (166HoPLA) microspheres for radio-embolization. This study was performed to investigate the distribution of intra-arterially injected microspheres both in vivo and histologically in order to establish an optimal size of particles for embolization of head and neck tumours. MATERIAL: Twenty rabbits with Vx2 auricular tumours were embolized via the caudal auricular artery with 4 different batches of microspheres: Radioactive (166)HoPLA microspheres sieved between 20 and 50 microm and Dextran hydrogel microspheres sieved between 20 and 100 microm (Dex20), 30 and 100 microm (Dex30) or 50 and 100 microm (Dex50). Dex20 and Dex50 microspheres were labelled with 99mTechnetium in six cases. METHODS: The average particle size of the microspheres was determined. The proportion of microspheres entrapped in the tumour was measured with a gamma camera. The distribution of microspheres around the primary tumour and spill of particles over into lungs or other organs was analysed from histological sections. RESULTS: The mean particle diameter varied from 19 to 66 microm: (166)HoPLA 19+/-11 microm, Dex20 40+/-19 microm, Dex30 50+/-19 microm, Dex50 66+/-21 microm. The 19 microm(166)HoPLA particles proved inadequate for embolization as 51% spilled over into the lungs, whereas over 95% of the 40-66 microm Dex microspheres were retained within the primary tumour area. Particle density in lung tissues proved significantly lower for the Dex50 group. Stray emboli to the brain occurred in two rabbits. CONCLUSION: The results of this investigation show that both Dextran hydrogel and holmium-166 poly(L-lactic acid) microspheres are potential candidates for embolization of head and neck cancer. In future studies, arterio-arteriolar anastomoses which might confound treatment should be identified and occluded. Particles with a number weighted mean diameter of at least 40 microm and a volume weighted mean size up to 70 microm should be used.

Analysis of Variance↗
PubMed2001

[Interaction between dentists, general practitioner and medical specialist].

Dentists and oral hygienists experience nowadays more frequently the need for special (medical) care for their patients. After consulting the family doctor or medical specialist the dental treatment must often be modified to fit the patient's general condition. The dental professional asks in these circumstances for expertise; in the field of oral medicine the dentist is the expert for the family doctor or medical specialist.

Clinical Competence↗
PubMed2000

Evaluation of the VX2 rabbit auricle carcinoma as a model for head and neck cancer in humans.

INTRODUCTION: This study investigates whether the VX2 carcinoma cell line, transplanted into the rabbit auricle, can be used as a head and neck cancer model. The biologic behaviour of this model is evaluated, comparing tumour transplantation with either tissue pieces or cell suspensions. MATERIAL: Thirty-six adult NZW rabbits received s.c. injections of VX2-suspensions (Group S) and 11 rabbits received solid VX2-pieces (Group P) into both auricles. METHODS: In Group S, 16 rabbits were sacrificed at various days before (S1) and 15 after (S2) the 28th day following transplantation. In the other five rabbits transplantation failed. Animals from Group P were sacrificed every 2 weeks after the 28th day. At autopsy the size of the primary tumours and of lymph node, lung and other metastases were assessed. If transplantation failed, the maximal tumour size and the time at which regression took place were recorded. Exponential trend lines were used to create growth curves of metastases. Differences between groups were evaluated with the chi2 test, correlations between parameters with Kendall's tau. RESULTS: The tumour take-rate in Groups S and P was 78% and 59% respectively. The maximal size and time at which regression occurred was significantly different, amounting to 83 +/- 7 mm2 at 10.4 +/- 1.6 days (Group S) and 243 +/- 30 mm2 at 20.9 +/- 2.0 days (Group P), respectively. Development of lymph node metastases was not different. In Groups P and S2, over 90% of the necks contained lymph node metastases. There was a higher incidence of lung metastases in Group S2 when compared to Group P (47% vs. 14%) but it was not statistically significant. A significant correlation (p<0.05) between weight loss and the size of lung metastases was found. CONCLUSION: Transplantation of the VX2-tumour with cell suspensions produces a useful head and neck cancer model for locoregional disease in which anti-tumour regimens against both the primary and lymph node metastases can be tested. Transplantation with tumour pieces is not advised as the take-rate is low and spontaneous remissions occur at a late stage.

Animals↗