Patient-specific sub-periosteal zygoma implant for prosthetic rehabilitation of large maxillary defects after oncological resection.

A 74-year-old woman needed a subtotal bilateral maxillectomy due to squamous cell carcinoma of the palate. Immediate and secondary reconstruction of the defect was not feasible, so the defect was closed with an obturator prosthesis wired to the zygoma complex. To improve the patient's severely impaired speech and swallowing, a patient-specific sub-periosteal implant (psSPI) was designed that matched the remnants of the zygoma complex. First, the patient's post-surgical anatomy was visualized through segmentation of the pre- and post-maxillectomy computed tomography data. Next, based on the data, a customized zygoma-supported framework was designed to support the obturator prosthesis. Surgical guides for intraoperative navigation were designed and three-dimensionally printed, along with an obturator prosthesis to fit the planned outcome situation. The preoperatively manufactured psSPI and obturator prosthesis matched the intraoperative conditions. The postoperative results were favourable; within a week after surgery the patient could speak and swallow normally without nasal leakage. No problems occurred during follow-up. These results indicate that a psSPI-retained prosthesis can be considered for the restoration of speech and oral functioning in cases with a largely compromised maxillary bone anatomy, accompanied by impaired oral functioning and no feasible conventional reconstruction options.

Multi-modality 3D mandibular resection planning in head and neck cancer using CT and MRI data fusion: A clinical series.

OBJECTIVES: 3D virtual surgical planning (VSP) and guided surgery has been proven to be an effective tool for resection and reconstruction of the mandible. Currently, most widely used 3D VSP approaches to mandibular resection do not include detailed tumour information in the VSP. This manuscript presents a strategy where the aim was to incorporate tumour visualisation into the 3D virtual plan. Three-dimensional VSP of the mandibular resections was based on the fusion of CT and MRI data which was subsequently applied in clinical practice. METHODS: All patients diagnosed with oral squamous cell carcinoma between 2014 and 2017 at the University Medical Centre Groningen were included. The tumour was delineated on the MRI data, after which this dataset was fused with the CT bone data in order to construct a 3D bone and tumour model for virtual resection planning. Guided resections were performed and post-operative evaluation quantified the accuracy of the resection. The histopathological findings and patient and tumour characteristics were compared to those of a historical cohort (2009-2014) of conventional mandibular continuity resections. RESULTS: Twenty-four patients were included in the cohort. The average deviation from planned resection was found to be 2.2 mm. Histopathologic analysis confirmed all resection planes (bone) were tumour free, compared to 96.4% in the historic cohort. CONCLUSION: MRI-CT base tumour visualisation and 3D resection planning is a safe and accurate method for oncologic resection of the mandible. It is an improvement on the current methods reported for 3D resection planning based solely on CT data.

Patient-specific pre-contouring of osteosynthesis plates for mandibular reconstruction: Using a three-dimensional key printed solution.

PURPOSE: In mandibular reconstructive surgery, the osteosynthesis plates require contouring according to the patients' individual anatomical situation. These plates are frequently contoured around a three-dimensional (3D) printed model. However, the translation to the actual patient can introduce inaccuracies and unwanted rotations in the condyles and mandibular ramus, due to malpositioning of the pre-contoured plate. MATERIALS AND METHODS: This article describes an easy-access method for exact translation of the pre-contoured plate to the patient's mandible. This is done by using 3D printed guides that allow pre-drilling of screw holes in both the contour model and the patients' mandible. The accuracy of the Key Printed Solution was analysed by comparing the anatomical landmarks on both the 3D planned and post-operative models. RESULTS: The method was applied to 4 cases. All landmarks were identified on both the 3D planning and post-operative computed tomographic data. This showed an average deviation of 1.0 mm between planning and the post-operative result. The inter-observer variation was 0.6 mm (intra-class correlation, 0.75). CONCLUSION: This article presents an easy-to-use method for pre-bending the osteosynthesis plate and subsequent accurate translation of the intended contour with corresponding screw hole locations. The method was proved to be accurate and time-efficient.

High sensitivity and negative predictive value of sentinel lymph node biopsy in a retrospective early stage oral cavity cancer cohort in the Northern Netherlands.

OBJECTIVES: In cT1-2N0, oral squamous cell carcinoma (OSCC) occult metastases are detected in 23%-37% of cases. Sentinel lymph node biopsy (SLNB) was introduced in head and neck cancer as a minimally invasive alternative for an elective neck dissection in neck staging. Meta-analyses of SLNB accuracy show heterogeneity in the existing studies for reference standards, imaging techniques and pathological examination. The aim of this study was to assess the sensitivity and negative predictive value (NPV) of the SLNB in detecting occult metastases in cT1-2N0 OSCC in a well-defined cohort. DESIGN: Retrospective study. The SLNB procedure consisted of lymphoscintigraphy, SPECT/CT-scanning and gamma probe detection. Routine follow-up was the reference standard for the SLNB negative neck. Histopathological examination of sentinel lymph nodes (SLN) consisted of step serial sectioning, haematoxylin-eosin and cytokeratin AE1/3 staining. SETTING: Two comprehensive oncology centres. PARTICIPANTS: A total of 91 consecutive patients with primary cT1-2N0 OSCC treated by primary resection and neck staging by SLNB procedure between 2008 and 2016. MAIN OUTCOME MEASURES: Sensitivity and negative predictive value. RESULTS: In all cases, SLNs were harvested. A total of 25 (27%) patients had tumour-positive SLNs. The median follow-up was 32 months (range 2-104). Four patients were diagnosed with an isolated regional recurrence in the SLNB negative neck side resulting in an 85% sensitivity and a 94% NPV. CONCLUSION: In our cohort, the SLNB detected occult metastases in early OSCC with 85% sensitivity and 94% NPV. This supports that SLNB is a reliable procedure for surgical staging of the neck in case of oral cT1-2N0 SCC.

[Oral medicine 11. Red and blue lesions of the oral mucosa]. / Oral medicine 11. Rode en blauwe veranderingen van het mondslijmvlies.

A red or blue mucous membrane disorder of the oral cavity can arise in response to a local cause of irritation, as a cause of an inflammation reaction to an infection, an auto-immune reaction to a local factor, and as an expression of an underlying systemic disorder. Moreover, it can be an expression of a premalignant or malignant mucous membrane disorder. Knowledge about and recognition of the different red and blue mucous membrane disorders can hasten the diagnosis and possible treatment. In the case of a premalignant (erythroplakia) or a malignant mucous membrane disorder (squamous cell carcinoma), the prognosis is better with early diagnosis and treatment than at a later stage of the disease.

[Oral medicine 9. Lichen planus and lichenoid lesions of the oral mucosa]. / Oral medicine 9. Lichen planus en lichenoïde afwijkingen van het mondslijmvlies.

The general dentist is sometimes confronted with white lesions of the oral mucosa. Oral lichen planus is the most common oral white lesion. The diagnosis can usually be made on the basis of the clinical aspect, but is sometimes made more difficult by certain abnormalities in the oral mucosa which clinically resemble oral lichen planus or by abnormalities which cannot be distinguished from oral lichen planus but have a different origin. Those lesions are classified as oral lichenoid lesions. Malignant deterioration has been described in allforms of oral lichen planus lesions and oral lichenoid lesions. There is no known method to predict or prevent malignant transformation. Nor are there any studies examining the efficacy of frequent follow-up visits. It seems sensible, in keeping with the tendency in recent literature, to schedule annual check-ups for patients to be on the safe side. These follow-up visits may reasonably be performed in a general dental practice.

[Oral medicine 8. Leukoplakia of the oral mucosa]. / Oral medicine 8. Leukoplakie van het mondslijmvlies.

Leukoplakia of the oral mucosa is a potentially malignant disorder, which means that there is an elevated risk oftransformation into a squamous cell carcinoma. The term oral leukoplakia is a clinical diagnosis for a predominantly white lesion which is not immediately recognizable as another well definable lesion which is white in appearance. Oral leukoplakia is generally an asymptomatic disorder of the mucosa with a prevalence of less than 2 per cent in the adult population. Tobacco usage is considered to be the most important etiological factor. Malignant transformation into a squamous cell carcinoma occurs in about I per cent per year. A patient with oral leukoplakia is generally referred to an oral and maxillofacial surgeon, who takes a biopsy for a definitive histopathological diagnosis. The outcome of the histopathological study, which may vary from hyperkeratosis to invasive squamous cell carcinoma, will determine the treatment. It is preferable that every leukoplakia is removed to reduce the risk of malignant transformation. Long term follow-up is indicated. Follow-up may in some cases be performed by the general dental practitioner.

[Oral medicine 7: white lesions of the oral mucosa]. / Oral medicine 7. Witte veranderingen van het mondslijmvlies.

White lesions of the oral mucosa may be due to highly diverse disorders. Most of these disorders are benign but some may be a malignant or premalignant condition. The disease is often confined to the oral mucosa. There are also disorders which are accompanied by skin disorders or systemic diseases. Many white oral mucosa disorders have such characteristic clinical aspects that a diagnosis can be made on clinical grounds only. When the clinical diagnosis is not clear, histopathological examination is carried out. Treatment depends on the histological diagnosis. In some cases, treatment is not necessary while in other cases, treatment is not possible since an effective treatment is not available. Potentially malignant disorders are treated.

[Oral medicine 10. Pigmented lesions of the oral mucosa]. / Oral medicine 10. Pigmentaties van het mondsslijmvlies.

Pigmented oral lesions may be due to the most diverse disorders. A distinction can be made between non-melanin-associated and melanin-associated pigmentations. Some lesions may be diagnosed on the basis of medical history and clinical research. In focal pigmented lesions, histological examination is necessary to establish a definitive diagnosis. Most disorders are benign but some may be malignant melanomas.

[Unrecognizable objects on a radiograph after a dental trauma. Cone beam computer tomography provided clarification]. / Vreemde structuren op een röntgenopname na een dentaal trauma. Cone beam-computertomografie bracht uitkomst.

A 12-year-old boy was referred to the Department of Oral and Maxillofacial Surgery of a university clinic, one week after initial treatment related to a dental trauma due to a fall on a swimming pool slide. The treatment by the dentist on duty consisted of repositioning and splinting the maxillary central incisors. However, a radiograph of the affected teeth showed some unrecognizable objects around the left incisor. The nature and localization of the objects were not clear. Therefore, a cone beam computer tomography was incisor's socket and that this tooth was not repositioned correctly. A retreatment was carried out consisting of removing the objects and repositioning and splinting the left central incisor. Cone beam computer tomography may be of great value in determining the nature and extent of a dental trauma as well as in evaluating the treatment provided.

[Cheek paresthesia by an osteosarcoma]. / Paresthesie van de wang door een osteosarcoom.

A 21-year-old woman was referred by the dental practitioner to an oral surgeon concerning a hard elastic swelling of the left cheek in combination with local paresthesia. Histopathologic and radiographic examination revealed an osteosarcoma in the left segment of the maxilla. Subsequently, the patient was referred to a medical centre for head and neck oncology. The treatment consisted of 3 courses neoadjuvant chemotherapy, followed by radical surgical resection of the tumor, and 3 courses adjuvant chemotherapy. One year after treatment, there was no sign of local tumor recurrence or metastases. An osteosarcoma is a malignant tumor of bone forming cells. About 10% of osteosarcomas are appearing in the head and neck region, primarily in the mandible and the maxilla. The treatment of choice is adequate surgical removal. Treatment with (neo)adjuvant chemotherapy seems to have additional benefit, but this needs further research.

Rehabilitation after mandibular reconstruction with fibula free-flap: clinical outcome and quality of life assessment.

Tumors (benign or malignant), osteoradionecrosis or osteomyelitis sometimes lead to large segmental resections of the mandible. Osteo(cutaneous) fibula free-flaps (OFFF) are used to reconstruct these defects. New anatomical relationships as well as possible irradiation of local tissues make dental rehabilitation complicated. The aim of this study was to determine the rate of dental rehabilitation with an implant-retained lower denture or fixed appliances, after segmental resection and reconstruction of the mandible with an OFFF. Data were obtained from 70 patients, who underwent segmental mandibular resection followed by reconstruction with an OFFF, from 1995 to 2005. Dental rehabilitation was defined as a patient, who after segmental mandibular resection and reconstruction with an OFFF, received an implant-retained lower denture or fixed appliances. Clinical and functional assessments, as well as quality of life and denture satisfaction were evaluated. Twenty-four of 70 patients received dental implants; 18 received complete dental rehabilitation. Only a small percentage of patients with segmental mandibular reconstructions with an OFFF received complete dental rehabilitation, mainly because of poor survival after treatment for malignant tumors of the oral cavity. The beneficial effects of dental rehabilitation with an implant-retained denture or fixed appliances, mainly favored cosmetic aspects, rather than oral function.

Interobserver and intraobserver variability in the clinical assessment of oral lichen planus.

BACKGROUND: In 1978, a clinical definition of OLP was formulated by the WHO. To date, the validation results of this clinical definition have not been published. The aim of this study was to evaluate interobserver and intraobserver variability in the clinical assessment of oral lichen planus (OLP). METHODS: Four clinicians examined a set of 159 clinical pictures of a white lesion in a group of 60 patients. Each reviewing examiner was asked to apply the WHO definition of OLP from 1978, and to categorise each case as either: (i) diagnostic of OLP, (ii) other definable lesion, or (iii) leukoplakia. After three months, each of the four reviewing clinicians was given the clinical pictures of 45 randomly retrieved cases from the original 60. Interobserver and intraobserver variability were assessed by calculation of unweighted kappa statistics. RESULTS: Interobserver agreement varied from 0.43 (moderate) to 0.77 (substantial), while the intraobserver agreement varied from 0.62 (substantial) to 0.92 (good). CONCLUSIONS: Although the clinical WHO definition of OLP seems to be more reproducible than the histopathological one, there is still a significant amount of subjectivity in using this definition. A set of clinical and histopathological diagnostic criteria with good interobserver and intraobserver agreements (kappa values > 0.8) is very important in enabling reproducible and reliable studies on OLP to be performed.

Tobacco usage in relation to the anatomical site of oral leukoplakia.

OBJECTIVE: Tobacco usage is the most important known aetiological factor in the development of oral leukoplakia. The purpose of this study was to investigate the possible relation of tobacco usage to the anatomical site of the leukoplakia. SUBJECTS AND METHODS: Clinical data regarding tobacco usage and localisation of leukoplakia obtained from 166 patients with oral leukoplakia. RESULTS: Leukoplakias in the floor of mouth appeared to be statistically significantly more often present in smokers than in non-smokers, compared to all other oral sites (P < 0.001; OR = 8.47 and 18.13 for men and women, respectively). On the contrary, leukoplakias on the borders of the tongue were statistically significantly more common among non-smokers, than smokers, compared to all other oral sites (P < 0.001; OR = 0.22 and 0.12 for men and women, respectively). CONCLUSION: The present study suggests that the influence of tobacco on the development of leukoplakia varies by anatomical site.

A modified classification and staging system for oral leukoplakia.

A proposal for a modified classification and staging system for oral leukoplakia (OLEP) has been presented in which the size of the leukoplakia and the presence or absence of epithelial dysplasia are taken into account. Altogether four stages are recognised. The presently proposed system should facilitate uniform reporting of treatment or management results of OLEPs in which a biopsy has become available. The system can easily be adjusted by replacing the histopathological criteria of epithelial dysplasia by a clinical subdivision in homogeneous and non-homogeneous leukoplakia for cases in which no biopsy is available.

A review of the recent literature regarding malignant transformation of oral lichen planus.

On the basis of a literature review of the period 1950-1976, Krutchkoff et al questioned the possible premalignant nature of oral lichen planus. Their criticism was largely based on insufficiencies of data in support of the initial diagnoses of the condition. In this article, a review of the literature from the period 1977-1999 has been described; the criteria used were those of Krutchkoff et al. Thirty-three (34%) of 98 reported cases were accepted as having sufficiently documented evidence of malignant transformation of oral lichen planus. Although this percentage is somewhat higher than the percentage reported by Krutchkoff et al, there apparently remains a need for uniformly accepted criteria to establish a firm diagnosis of oral lichen planus. Only when such criteria are available will it be possible to conduct long-term prospective studies on the suggested possible premalignant nature of oral lichen planus.

[Oral carcinoma in 34 dogs]. / Het mondholtecarcinoom bij de hond. Ervaringen met 34 dieren.

In a retrospective study, the epidemiologic data, treatment results and survival times of dogs with an oral squamous cell carcinoma in the period 1983-1996 have been reviewed, using the data base of the Department of Clinical Sciences of Companion Animals of the Faculty of Veterinary Medicine of the University of Utrecht, The Netherlands. The etiology of oral squamous cell carcinoma in dogs is unknown. For various reasons, such as extent of the disease, active treatment was undertaken in only 22 out of 34 dogs. Two dogs were lost during follow-up. Sixteen of the remaining 20 dogs who underwent surgical treatment for their oral squamous cell carcinoma were alive, one year postoperatively, apparently without tumour. Postoperative radiotherapy may even improve the survival rates.