Diagnostic and Therapeutic Endoscopy, Vol. 1, Pp. 57-62 Reprints Available Directly from the Publisher Photocopying Permitted by License Only Clinical Experience with a New Type of Rhino-larynx Electronic Endoscope Pentax Vnl-1530

We observed recordings of pictures obtained from patients with diseases of the larynx by using a new type ofrhino-larynx electronic endoscope, PENTAX VNL-1530 connected to a video processor, PEN-TAX EPM-3300 (Asahi Optical Co., Ltd.). The electronic endoscope differs from the fiberoptic en-doscope in that it contains a small light-sensitive charge coupled device (CCD) chip that is attached to the tip of the endoscope. This electronic endoscope has the smallest CCD camera of 5.1 mm in diameter , in the tip portion, and can be passed through the nasal passage into the laryngeal cavity. The dynamic image provided by this system is superior to that obtained by a flexible laryngofiberscope in resolution of the detail. The system with this electronic endoscope was introduced and some clinical cases were presented.


es.Precise di
gnosis ofdisease at an early stage leads directly to the proper treatment of the disease.Due to advances in electronic equipment, a rhino- larynx electronic endoscope has been developed with a small CCD (charge coupled device) camera in the tip portion, which is about 5.0 mm in diameter.The purpose of this paper is to report on a new type of rhino-larynx elec- tronic endoscope system which allows for smooth inser- tion through the nasal passage into the laryngeal cavity.


INSTRUMENTS AND METHODS

Electronic endoscopic examinations have been carried out using a

w type of rhino-larynx e
ectronic endoscope, Address for correspondence: Dr. Masahiro Kawaida, Department of Otolaryngology, Tokyo Metropolitan Ohtsuka Hospital, 8-1, 2-chome Minamiohtsuka, Toshima-ku, Tokyo 170, Japan.


57

PENTAX VNL-1530 (Asahi Optical Co., Lt .) (Fig. 1).The dimensions and characteristics of this endoscope are shown in Table 1.

The electronic endoscope contains a small light-sensi- tive CCD chip that is attached to the tip of the endoscope as a miniature TV camera.The image detected by the CCD chip is passed in the form of an electronic signal, through the endoscope to a video processor, PENTAX EPM-3300 (Asahi Optical Co., Ltd.), which changes the signal to a form capable of being visualized on the TV monitor by the RGB sequencing system.Light supplied from a source in the video processor is passed through the light guide of the endoscope via a glassfiber bundle for illumination.It is possible to add various recording devices such as a videotape recorder, a videoprinter, and an automatic mon- itor photo unit to this system.A freeze-frame facility is also provided.A subscreen mode permits simultaneous viewing of frozen and moving images via the main screen and sub-screen.The other features ofthe endoscope, such as the control mechanisms of the tip, resemble those of conventional flexible laryngofiberscopes.PENTAX EPM-3300  (RGB seq.system)   vocal fold nodules (patient 1). Figure 4 shows the left vocal fold polyp (patient 2).

The quality of the images obtained by the electronic en- doscope system was outstanding.Color reproduction of the laryngeal mucosa appeared normal, and resolution was excellent.

The maneuverability of this rhino-larynx electronic en- doscope is identical to that of conventional flexible laryn- gofiberscopes DISCUSSION When this electronic endoscope is used in a patient, sur- face anesthesia with 4% lidocaine-HC/spray applied into the nasal cavity is performed.The patient is examined in

e seated
osition.The endoscope is then passed through the nasal passage and introduced into the laryngeal cav- ity (Fig. 2).


PATIENTS

Two patients were examined using this electronic endo- scope syste

Patient
was a 35-year-old woman who had vocal fold nodules.Patient 2 was a 50-year-old man who had a left vocal fold polyp.


RESULTS

A picture taken during the examination is shown in Figure 2. Recorded pictures obtained by freeze-frame are shown in Figures 3a and 4a.In addition, pictures obtained by videography with a conventional flexible laryngofiberscope are also shown in Figures 3b and 4b. Figure 3 shows Laryngoendoscopy bega with the description of the first flexible laryngofiberscope in 1968 (Swashima and Hirose, 1968).Not long afterwards, the rigid laryngotelescope (Honda et al., 1977) and curved laryngotelescope (Saito  et al., 1984) were developed as a rigid type of laryngoen- doscope.More recently, video laryngoscopy using a laryn- goendoscope connected to a color video camera and a videotape recording system was developed (Yoshida et al.,  1979; Yanagisawa et al., 1981).

The flexible laryngofiberscope has the advantage that it can reach objects more easily.However, it has the dis- advantage that the obtained image is very rough.The me- chanical characteristics of the electronic endoscope, PENTAX VNL-1530 are identical to those of the flexible laryngofiberscopes.However, the electronic endoscope differs from the fiberoptic endoscope in tha it contains a small light-sensitive CCD chip that is attached to the tip of the endoscope (Classen and Phillip, 1984; Matek et al.,  1984).This endoscope provides high quality, optimum brightness, superior color balance, and high resolution of the TV image to enable optimal diagnosis.

Figure 2 The device in clinical use.The patient as examined in a sitting position and the endoscope was passed through the nasal passage.

Documentation o the entire examination on videotape is possible.Individual views can be photographed directly from the monitor screen using the freeze-frame facility and automatic monitor photo unit.Furthermore, it will also be possible using new techniques such as still video floppy discs to record the findings in a rapid manner.

The electronic endoscope, PENTAX VNL-1530 has a small CCD camera in its tip, which is 5.1 mm in diameter.

Examination with this electronic endoscope system is eas- ily performed through the nasal passage into the laryngeal cavity after only surface anesthesia.Patients experience less pain.The dynamic image provided by this system is supe- rior to that obtained by conventional flexible laryngofiber- scopes with reg rd to resolution of details.The main advantage is in the high quality video image reproduction on a TV monitor.This may help in education and better de- Figure 3 Clinical f ndings of vocal fold nodules (patient 1).a, A picture photographed with the freeze-frame facility of this electronic endoscope system and automatic monitor photo unit.b, A picture obtained by videography with a conventional flexible laryngofiberscope.finition of the image that the physician uses for diagnostic purposes.Through the use of the processor terminals, it is also possible to access various computer products.

There is one problem that must be addressed.Stroboscopic examination is the most practical way to de- termine the vibratory mode of the vocal folds during phonation in the field oflaryngology (Yoshida et al., 1979;

ito et al.,
1978; Fukuda et al., 1990).However, it is dif- ficult to keep a record of stroboscopic images using an electronic endoscope employing the RGB sequencing sys- tem.In order to observe and record stroboscopic images using an electronic endoscope, it will be necessary to de- velop a ne