contact endoscope.pptx and it’s used in ENT

This ppt tells about the advantages of contact Endoscopy

1. Contact Endoscope

2. The investigation of blood vessels and their microcirculation been an area of interest to surgeons for many years. In 1970, surgeons 1 started research on the arterial vascularization of the larynx. Over the years, anatomical and clinical research on the pathways of extension of laryngeal tumours has been published. The systematic evaluation of operated specimens allowed for a better understanding of the progression and invasion of the laryngeal tumours A group of endoscopes were produced by Karl Storz (1995)7 that were specifically designed for the intraoperative evaluation of the larynx. This technique is called contact endoscopy and typically involves examination of the superficial epithelium of the larynx INTRODUCTION

3. The first description of contact endoscopy is atributed to Desormaux in 1865, who observed the vascular network of the bladder mucosa . The development of this technique was only possible due to technological progress. In 1955, Jaupitre promoted contact cystoscopy associated to photography and cinematography and in 1983, Hamou developed the microcolpohysteroscopy used in gynaecology . This technique allowed for the better comprehension of the pathology of the uterine cervix, but due to its complexity and difficulty, its use remained only within a limited number of centres . The contact microlaryngoscope was developed in 1995 and the study of the larynx using contact endoscopy was initiated.

4. Contact endoscopy, using amplifications of 60 x and150 x, allows for the in vivo and in situ observation of the mucosal vessels . By staining the mucosa with methylene blue , it is possible to visualize the cells of the superficial layer of the mucosa of the larynx, which allows diagnosis, the evaluation of the extension of the lesions and , when tumour is present, defining the safety margins . The advantages of this technique led to it being used daily in clinical practice

5. With contact endoscopy, anatomical-pathological concepts of mucosal illnesses are evaluated clinically in multiple sites and stages, at times associated with aetiopathological factors. With this technique vascular and cellular alterations of the mucosa can be observed both in the outpatient clinic and in the operating theatre. With contact endoscopy, the notion of illness has surpassed the classic concept of the macroscopic lesion that was biopsied. The objective of contact endoscopy is not to visualize at the surface what is expected to be observed from histological sections and it should not be considered a substitute for biopsy. Instead it is a clinical method that adds to the information available during an endoscopic examination. It is an anatomical-pathological examination that supports the cytology.

6. At the level of the larynx and hypopharynx contact endoscopy is performed under general anaesthesia with endotracheal intubation . The nasal mucosa, nasopharynx, mouth and oropharynx can be observed, in many cases, without the need for any anaesthetic . For the observation of the vessels the contact endoscope is applied directly on the mucosa without any staining. The microcirculation is visible with illumination from a regular endoscopy light source. However when the illumination is changed for the Olympus ‘narrow band imaging’, the emitted light is absorbed by the haemoglobin of the erythrocytes, improving substantially the visibility of the vascular network allowing the identification of deeper vessels . To observe the cells of the epithelum the mucosa is stained with methylene blue. The contact endoscope is gently applied to the mucosal surface. The colouration lasts for 4 to 5 minutes.

7. CELLULAR AND MICROVASCULAR STRUCTURE OF THE MUCOSA OF THE UPPER AERODIGESTIVE TRACT The mucosa that covers the upper aerodigestive tract is constituted by ciliated epithelium and by squamous stratified epithelium in accordance with the function of the different regions. Acting as an interface with the external environment, this mucosa is subjected to frequent stimuli and insults that may cause clinical and subclinical alterations at different tissue levels. Alterations of one part of the aerodigestive tract may cause consequences of other anatomical territories within the aerodigestive tract.

8. NORMAL AND PATHOLOGICAL PATTERNS Normal pattern When observed by contact endoscopy the cells of normal squamous epithelium have a polyhedric shape, being in continuity with each other. The nuclei are round and dark. The cytoplasm has a light blue colouration . The nucleus : cytoplasm ratio is regular and the general morphological pattern is homogeneous The ciliated epithelium observed with contact endoscopy has a distinct appearance. The nuclei are round and dark but the cytoplasm limits are difficult to define . The nuclei are very close to each other creating a higher density of nuclei per optic field The transition of squamous to ciliated epithelium is easily observed with contact endoscopy. In some cases there is a very sharp line of separation

9. Contact endoscopy allows a detailed observation of the mucosal vessels. The most superficial microvascular network is situated immediately below the basal membrane. The morphology of the vascular network is conditioned by the topography and function of the mucosa . In most of the mucosa of the upper aerodigestive tract the vessels have a course parallel to the surface and are connected by many anastomoses constituting a plexus

10. Chronic inflammation When chronic inflamed mucosa is observed through contact endoscopy , the general aspect of the squamous epithelium is homogeneous, but the size of the nuclei is larger with an increased nucleus / cytoplasm ratio . As the cellular turnover is accelerated due to the inflamation , more immature cells become visible at the surface, similar to those that are observed at the intermediate layers of the normal epithelium. The mucosa of chronic inflammation has a higher vascular density due to the increased number of vessels and vessel enlargement. However, the pattern of distribution remains organized.

11. FUNGAL INFECTION In some cases of chronic inflammation, in addition to the typical pattern of increased diameter of the nuclei, it is possible to identify with contact endoscopy small dark dots that seem to spoil the image. These correspond to fungal spores Hyphae and miceliums can also be observed as well as filamentous structures. Contact endoscopy has identified that fungal infections are in many cases associated with chronic inflammatory changes , and dysplastic or neoplastic lesions in different anatomical sites. In general the fungal infection does not disturb the microcirculation more than inflammation due to other aetiologies . However , in more aggressive forms of disease there are profound vascular changes, including aberrant shaped vessels causing thrombosis and tissue necrosis

12. KERATOSIS In the same patient, and even within the same lesion, different degrees of keratinization can be observed by contact endoscopy. Initially isolated cells without nuclei are identified. Unfortunately, it is not possible to identify individual cells in areas of amorphous or laminar structure Keratosis is present in different clinical entities. In some cases keratinization is very discrete while in others it is pronounced. Occasionally keratosis is not suspected and its finding with contact endoscopy is a surprise. With leukoplakias , in addition to keratosis, other types and degrees of cellular alterations can be observed by contact endoscopy, including heterogeneity of the cellular population. The variety of the cellular images can be accounted for as different pathological alterations such as hyperkeratosis and dysplasia can occur simultaneously. In other clinical entities such as chronic inflammation, papillomas and tumours , keratosis can also exist in different degrees . While in some cases the vessels pass below the area containing keratosis they may sometimes surround the leukoplastic lesion .

13. TUMOUR In carcinoma, contact endoscopy identifies the marked cellular irregularity and heterogeneity. The nuclei have different sizes, shapes and colouration . The nucleus : cytoplasm ratio is very irregular . Sometimes nuclear inclusions, prominent nucleoli and mitosis are identified . The angioarchitecture is also very disturbed. The blood vessels are atypical with differences in size and shape,but also ectasias, haemorrhages and reduced blood flow, which results in thrombosis . Depending on the anatomical region of the tumour , distinct images can be observed. In places where the tumour growth infiltrates the deep planes but does not reach the surface , vascular alterations can be identified with normal superficial epithelial cells. The direct demonstration in vivo and in situ of a tumoural pattern in the operating room and in the outpatient clinic is a reality. Contact endoscopy also allows the assessment of transition areas, the identification of early stages of disease, guidance of biopsies, guidance of sample collections for cytology, establishment of safe margins and demonstration of different diseases.

14. PAPILLOMA Contact endoscopy contributes to the assessment of the papilloma , allowing the identification of its extent, offering better conditions for removal and potentially reducing the risks of residual disease. The direct application of the contact endoscope allows the identification of the typical vascular loops. The degree of visualization of the vascular structure depends on the density of the keratosis that is associated with the disease in some cases. With the vital stain, in some cases it is possible to identify the typical koilocytes (ballooned cells and inflammatory infiltrates . Koilocytes are typical of human papillomavirus infected cells.

15. Papilloma of the larynx Papilloma of the larynx. Vascular axis of the papill asobserved with NBI, 60X .

16. Papilloma of the larynx. Koilocytes are identified, 150X.

17. Advantages

18. limitation

19. conclusions

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