Choosing the Right Medical Endoscope

Endoscopy is a minimally invasive technique for diagnosis and surgery. The endoscope can be inserted via the mouth when exploring the stomach or bronchial tubes; via the nostrils for the nasal cavities, vocal cords or sinuses; and via the anus to examine the colon. For other examinations, it may sometimes be necessary to make small incisions to insert the endoscope, for example in the abdomen (laparoscopy).

There are three main types of endoscopes:

• The rigid optical endoscope: is a rigid rod with lenses. One end of the endoscope has the lens, and at the other end there is a socket for connecting a light source and the eyepiece. It is also possible to clip a video camera head onto it.
• The fiberscope (or flexible optical endoscope): works on the same principle as the rigid optical endoscope except that its stem is flexible because it is made of an optical fiber. This makes it easier to access sinuous areas, such as certain parts of the larynx. On the other hand, due to its thin, flexible and fragile stem, the fiberscope needs to be used more delicately.
• Video-endoscope: the rod is usually flexible and at the end of it is a CCD sensor that allows for the acquisition of video images. For certain applications (such as a polypectomy, prostate enucleation, etc.), the stem may have one or more working channels for endoscopic instruments. The handling of a video-endoscope can be delicate, especially because of the fragility of the CCD sensor at its end. Some video laryngoscopes can be rigid. They are made up of a blade and can be equipped with an integrated video monitor to enable quick viewing, especially for an emergency intubation for example.
  

  Karl Storz video gastroscope

A rigid endoscope is often used for applications where access to the inspection area is not very sinuous, such as cranial sinuses, the ear canal, urinary devices, etc. It is coupled to a light source and sometimes a video camera is attached to the lens.

It can have a wide-angle lens, which allows for wide framing of close objects. It also offers high-definition images thanks to transmission by optical lenses. The rigid structure of the endoscope is due to the succession of lenses aligned in the tube. This allows the practitioner to obtain a clear image of the inspected area.

Lastly, rigid endoscopes can have one or more channels through which an endoscopic instrument can pass. These can be forceps to grasp or remove foreign bodies or tissue samples; scissors to cut tissue; brushes to collect cells or a lace to catch polyps for example.

Hipp Endoskop Service laparoscope

Each type of endoscopy has its own risks, but overall these are essentially risks related to infection. To limit these risks, the endoscope is systematically disinfected before being introduced into the body. Other accessories are also sterilized or are sometimes single use.

Depending on the part of the body examined, local or general anesthesia may be recommended. The possible risks associated with any anesthesia must therefore also be taken into account. A pre-anesthetic consultation is mandatory.

Finally, some complications can be caused by the manipulation of the endoscope itself. The risk may then be of esophageal, gastric or intestinal perforation. But these kinds of complications are very rare.

The advances made in imaging have been applied to video-endoscopes, allowing for interesting alternatives to traditional diagnosis methods:

• Endoscopic ultrasound: mainly used in gastroenterology, particularly for the exploration of the pancreas and bile ducts, it facilitates the detection of possible tumors, gallstones, etc. by coupling an ultrasound probe to the video-endoscope. It is often more precise than MRI or CT for certain types of investigations. This technique, which combines endoscopy and ultrasound, makes it possible to visualize not only the inside of the canal but also its adjacent structures. The probe also allows you to visualize the vascularization of the tissue. Endoscopic ultrasound has some limitations, however, such as availability of the equipment, cost and the ultrasound resolution in terms of image quality. Other optical imaging techniques could therefore be developed to overcome these obstacles.

The end of the rod of an Olympus ultrasound video gastroscope

• Increasing the quality of the electronic zoom: the power of the electronic zoom depends on the resolution of the video sensor. This power is constantly increasing for new-generation video-endoscopes, thanks in particular to the use of megapixel CCD sensors.

• Autofluorescence imaging: when radiation excites tissue at a specific wavelength, certain molecules (fluorophores) will release the absorbed energy in the form of a very specific radiation. Spectrum analysis and the measurement of the emission time of the emitted radiation will make it possible to characterize its nature. This fluorescent image, when placed on top of the traditional image, helps diagnosis considerably.

The development and application of the following techniques in endoscopy are also worth noting: confocal microscopy and optical coherence tomography. Optical coherence tomography (OCT) allows for very high resolution three-dimensional analysis of tissue.