Insertion Tube Endoscope
A flexible insertion tube endoscope is a common medical device that is used to look inside the human body. The procedure is generally done under sedation or anaesthesia.
Before the endoscope is inserted, your doctor will talk to you about your medical history and answer any questions you may have. They will also ask you to sign a consent form.
The insertion tube
An insertion tube endoscope is an instrument used to examine the internal organs of the body. It is typically used to diagnose, treat, or confirm a disease or condition. An endoscope is also used to help with other medical procedures, such as a biopsy or cytologic sampling.
The insertion tube is the part of the endoscope that is inserted into the body, usually through the mouth or an abdominal opening. It contains tubes that carry air and water to the instrument tip, a water nozzle for washing debris off of the objective lens, and other accessories.
Generally, the insertion tube is made of a stainless steel tubular mesh. It is then coated with a polymer to give it a smooth outer surface and make it more durable. The insertion tube also has spiral bands of metal wires wound in opposite directions to give it a rigid exterior and allow the tube to rotate accurately when torqued.
The diameter and length of the insertion tube are determined by the anatomy of the body to be examined. For insertion tube endoscope example, an esophagus is 4 to 6 mm in diameter and 9 to 10 cm long, while a small bowel is 7 mm in diameter and 12 to 15 cm long.
Insertion tubes for gastroscopes and colonoscopes are a little longer than those for bronchoscopes. The larger insertion tube size allows the endoscopist to see deeper inside the intestines, while still being short enough to avoid causing perforation of the lining or compression of the airway.
Most gastroscopes and colonoscopes contain tubes for suction (biopsy), air, and water feeding; an additional tube for a forward water jet; four angulation control wires; fine electrical wires connecting the charge-coupled device (CCD) image sensor at the distal tip of the endoscope to the video processor; delicate glass fibers that bring light from the light source to the tip of the endoscope; and a bending section that bends the insertion tube back into a normal position.
During endoscopic examination, the physician manipulates the angulation knobs to move the distal tip of the insertion tube up or down and left or right, as needed. This is done by either the ring and small fingers of the right hand or the left hand, depending on the model of the instrument.
The bending section
A bending section is a flexible section of an insertion tube endoscope that allows it to be manipulated by the operator. It is adapted to allow the endoscope to travel through selected body channels such as the esophagus, the colon, the stomach and the large intestine.
The bending section may be made of various components. It is typically comprised of two helically wound metal strips, one loosely surrounding the other. The strip is controlledlably steered by at least one cable extending through the tube and connecting to a control mechanism in the housing of the endoscope.
In addition to the helically wound metal strip structure, other bending structures have been proposed. The most common of these is the U.S. patent number 4,869,238 to Opie et al.
This bending structure is comprised of a first pair of protrusions on a first surface and a second pair of protrusions on a second surface, each protrusion defining a horizontal bending axis and an intersection of the horizontal and vertical bending axes defining a longitudinal bending axis.
Despite its simplicity, this structure has many shortcomings including: 1. It is susceptible to looping in some circumstances such as during colonoscopy; 2. The flexible shaft of the bending section is prone to wear and tear which makes it difficult to handle with a fingertip; 3. In order to keep the distal tip of the insertion tube from rotating during use, there must be sufficient stiffness between the shaft and the bending section.
Another problem associated with this bending section is that it becomes distorted and loses its shape over time. This is due to the fact that the wires used to move the bending section stretch over time.
The present invention provides an improved bending structure for the bending section of an insertion tube endoscope. It comprises four cylindrical apertures positioned on an inside surface adjacent the first and second protrusions and extending through the vertebra to receive control wires selectively retracting and extending to turn the bending section a desired degree of bend. The inside surfaces of the apertures are generally planar and do not have a chamfer, which helps to provide torsional stability for the bending section. In a preferred embodiment, the clearance for the control wires through the apertures is balanced with the thickness of a metal braid which covers the bending section.
The insufflation channel
The insufflation channel is an integral part of the insertion tube endoscope, and it allows air to be insufflated into the patient’s gastrointestinal tract as necessary. This enables a thorough examination of the mucosa and distending of the viscus. It also allows water to be blown down the air channel and into the patient’s gastrointestinal tract to rinse away debris and mucus.
The insufflating channel is connected to a regulated source of insufflation gas at the proximal end. When an insufflation pressure is reached, a one-way valve closes and the gas enters the channel, exiting the distal tip through a release hole in the handle of the endoscope (see Figure 3.2). The insufflation channel can also be used for vacuuming or suctioning the patient’s gastrointestinal tract.
Control of the insufflation channel is accomplished by the physician using his or her left hand to manipulate a control knob on the end of the insertion tube. Some physicians use their left index finger to control alternately the suction and air/water valves while the ring and small fingers grip the instrument, while others control the up-and-down angulation knob with their left thumb.
A tensioning wire runs the length of the insertion tube. A ring attached to this wire controls the amount of stiffness. When this pull wire is in the “soft” position, it provides no additional stiffness to the insertion tube beyond that provided by the polymer coat and wire mesh.
When the ring is in the “hard” position, it adds stiffness to the insertion tube and the control section at the proximal end. This stiffening system can be used to reduce the risk of bending the tip during examination.
An automatic pressure-regulated surgical insufflator, the UHI-3, was compared to a manual endoscopic CO2 insufflator, the UCR, in an inanimate bench study followed by an acute animal experiment. The data obtained from these experiments were used to develop a reproducible index of the pressure at which endoluminal visualization is optimized. The index was then applied to 80 cases, which were analyzed in order to insertion tube endoscope obtain reproducible endoluminal pressure values that can be utilized for a wide range of procedures.
The accessory channel
Endoscopy is the insertion of a long, thin tube directly into the body to observe an internal organ in detail. The scope is used to investigate or diagnose a disease or disorder, or to perform treatment such as cauterization (sealing with heat) of bleeding vessels or removal of polyps.
The endoscope consists of many parts, each delicate and subject to damage. One of the most fragile and vulnerable sections is the bending section, which is covered by a soft, flexible rubber sheath. This area is susceptible to abrasion from the tip of the instrument that is being used, and it should always be protected.
A deflectable portion of the insertion tube, called the bending section, can be manipulated by the endoscopist to change the view of the object being examined. This bending section is positioned between the objective lens and the light source connector at the distal tip of the insertion tube.
This bending section is constructed differently from the rest of the insertion tube, and it is composed of oddly shaped metal rings that are attached to each other via a series of freely moving joints. The joints are configured so that two sets of pivots allow the bending section to curl in an up-and-down and right-and-left direction, respectively.
To control the deflection of the bending section, four wires run the length of the insertion tube and are firmly attached to the tip of the bending section at the 3 o’clock, 6 o’clock, 9 o’clock, and 12 o’clock positions. When the endoscopist pulls on one of these wires, it causes the bending section to curl up and achieve what endoscopists call “up tip deflection.”
A pressure compensation valve is also located in this region. The valve prevents the endoscope from being damaged by changes in pressure during ethylene oxide gas sterilization or shipping by air. It is also attached to a manometer-type pressure tester that can be used to check the system for leaks, which are an easy and safe way to keep the endoscope in good condition and increase diagnostic and therapeutic yields.
