Endovideostroboskopija u ranoj dijagnostici karcinoma glasnica
Stroboscopy in early diagnosis of carcinoma of the vocal cords
UniversityУниверзитет у Крагујевцу
FacultyУниверзитет у Крагујевцу, Факултет медицинских наука
Chronical laryngitis is a long-term inflamatory process of the larynx mucus. The fundamental meaning of the stroboscopy is in the clinical evaluation of the patient with the chronical laryngitis (as well as in a possible precancerosis) which enables the early discovery of the malign lesions. We were especially interested in area or points of absence of the mucus wave, which is equivalent to the so-called adynamic or non-vibrating segment, as a warning signal which requires an immediate hystopathological verification. At the same time we consider this the most important goal of the every-day endovideolaryngoscopic examination. Ideally, practically every office should have this important instrument which improves the precision of the evaluation and enables the detailed following of the vibratory abilities of the observed vocal cord, which is especially important when evaluating the theraputical results with chronical laryngitis. Stroboscopy presents the optical method of the observation of the succesive fast movements of the vocal cords which can't be seen with the naked way. The impulse source (intermittent) of the stroboscopic light is used for illumination of the movement segments of the vocal cords. The stroboscopic light can be synchronous or asynchronous with the frequency of the basic tone so that we can get a slow motion view from the large number of images. The slow motion image is an illusion of the continuous image because the stroboscopic light does not change the speed of the vibration but rather gives a single image. The image showed stays on the retina for 0.2 seconds so the interval necessary for the eye to register the two images is 0.2 seconds. The Talbot's law explains that no more than 5 images per second can be interpreted. If this time interval is even shorter, the number of images per second is larger, so it comes to the merging of images. It is important to keep in mind that there is no strict correlation between the observed template of the vocal vibration and the existing pathological condition. The tissue changes in the mantle of the epithel which can lead to rigidity of the vocal cords. The template can vary depending on the degree of the pathological changes of the tissue. The open phase of the vibration cycle has been expanded, the vibration amplitude narrowed, the mucous wave reduced, and the vibrations can be regular, semi-regular, or irregular. The mucous wave also depends on the size of the vibration amplitude. It is reduced or it is diminishing with the increase of the rigidity of the vocal cords (as with chronical laryngitis). The cancer begins in the mantle (epithel) of the vocal cord. It vibrates asymetrical and irregularly and the mucous way is first decreased, and then disappears. In the end it comes to the complete vibration immobility. Non-vibrating vocal fold can point to a possible cancerous lesion, and the fixation of the vocal cord points to a deep invasion of the larynx muscle. The golden standard for diagnosing the vocal fold cancer is microlaryngoscopy with biopsy and hystopathological tissue verification, but the importance of the endovideostroboscopy is great because of the clinical observation of the vocal cord template (if such exists) or a possible existance of the adynamical segment. Research goals: determine the importance of the endovideostroboscopy in early diagnosis of the vocal fold cancer, determine to what degree is the endovideostroboscopy a sensitive method for the discovery of the cancer of the vocal fold in early stages; determine if the endovideostroboscopic evaluation, compared to a classical ORL evaluation, gives more precise information about the existence of the pre-cancerous lesion within the chronical laryngitis and determine if the demographic and socio-economic characteristics of the examinees has a factor in the appearance of the chronical laryngitis and the vocal fold cancer. Methods: the study has been conducted at the ORL clinic in the Clinical center of Kragujevac from 2008 to 2012 and it was conducted on 300 patients with the chronical laryngitis. The first group (the eximaned group, n=102) were the dysphonical patients with chronical laryngitis that had the microlaryngoscopy with biopsy and hystopathological tissue verification, (based on the endo videostroboscopic findings) performed on them because of the doubt that there indeed was a cancer. The second group (the control group, n=198) were the patients with chronical laryngitis with which there was a possibility of cancer, which were examined using the normal clinical evaluation (indirect laryngoscopy). The microlaryngoscopy with biopsy and hystopathological tissue verification was also performed on them.