Colonoscope

Everything There Is to Know About Colonoscopes

A colonoscope is an instrument designed for examination of the terminal ileum and the entire colon.  Colonoscopy has become the principal method for the diagnosis and treatment of colon and rectal diseases. 

A proximal housing, an insertion tube, and an umbilical cord are the three components of the device. The flexible insertion tubes of a video-colonoscopy contain a fiber optic light bundle, which takes the light from the light source and transmits it to the tip of the endoscope. The light illuminates the field of view in the patient’s colon.

CCD detects the video images and then transfers them to the video processor, display monitors, and recording devices, respectively. In practice, the procedure is essential in diagnosing intestinal cancer, which is the second leading cause of cancer deaths in the US. The instruments excise colorectal polyps or tumors, control any bleeding, and remove foreign bodies. 

These endoscopic procedures often eliminate the need for invasive surgical, therapeutic, and diagnostic procedures. 

History of Colonoscopes

In 1960, Dr. Hiromi Shinya and Dr. William Wolff established an upper gastrointestinal fiberoptic endoscope. This instrument was used for the examination of the whole colon until, in 1969, they performed the first colonoscopies with the new device. 

Regarding the examination of the entire colon, the retrograde colonoscopy began in June 1969. Endoscopic excision of polyps throughout the colon started in September of 1969. Users of the method faced significant opposition from the people who considered the process unduly, dangerous, and unnecessary. 

The instrument’s quality has improved in the last two decades, including advancements with adenoma detection rates, withdrawal times, and cecal intubation rates. Various technical advances have occurred, which include virtual chromoendoscopy and chromoendoscopy techniques.

 Documenting multiple diseases is much easier because of breakthroughs in video and photography during the procedure. During the process, the use of anesthesia plays a significant role in sedating the patients, which has increased patient satisfaction.

Indications to use Colonoscopes

Many research studies have determined the significant indications, the diagnostic yield, and the appropriateness of colonoscopy for each sign. One such study gave seven indications: iron deficiency anemia, rectal bleeding, polyp follow-up, cancer follow-up, abnormal bowel habit, abdominal pain, and others like abnormal barium enema and colitis.

The indications of the procedure are primarily divided into diagnostic and therapeutic indications.

Diagnostic indications involve:

Lower Gastrointestinal Bleeding

This type of bleeding occurs in the form of melena, occult bleeding, severe hematochezia, or scent intermittent hematochezia. Routine or urgent observation with a colonoscope is required for those who experience lower GI bleeding. Patients who experience occult gastrointestinal bleeding can exclude adenomatous or malignant etiologies by getting a colonoscopy done. In patients presented with melena, to identity, any upper GI causes upper GI endoscopy. If it does not reveal a source, then the instrument is necessary to identify any colonic source. This condition is prevalent in patients with intermittent hematochezia who have any of the following risk factors: family history of colon cancer, greater than 50 years old, or other alarming symptoms like change in bowel habits, anemia or weight loss.

Colon Cancer

According to the WHO report, colorectal cancer (CRC) is the second most common cancer in women and the third most common cancer in men. The family history of CRC is a significant risk factor for CRC. The first-degree relatives of such patients have 2-3 folds of increased risks of dying from CRC. There is an inverse association of the risk and the age of Dx of an affected family member. A colonoscopy is necessary when polyps are present in the colon, and surgery is the final decision as the preoperative colonoscopy shrinks the need for colonic polyps for laparoscopic management.

Surveillance After Polypectomy    

They constitute 20% of the colonoscopies performed as delaying surveillance can increase the risks to the patients by increasing the chances of missed interval cancer. The current recommendation for individuals of average risk (i.e., general population) is to get a colonoscopy every ten years.

CRC Post-Resection Surveillance

The use of the procedure in patients who have had CRC resection helps detect metachronous polyps and CRCs as well as anastomotic recurrences of primary cancer at a stage that easily allows further treatment. Otherwise, repeat the procedure after three to five years.

Inflammatory Bowel Disease & Other Colitis

The colonoscope apparatus detects inflammatory bowel diseases, namely Crohn’s disease (CD) and Ulcerative Colitis (UC). Colonoscopic differentiation and diagnosis between CD and UC, assessment of the severity and extent of disease activity, the effectiveness of treatment, surveillance of malignancies, endoscopic surgeries like stricture dilation all come in indications of colonoscopy. Other forms of colitis, such as radiation colitis, vascular, infectious, and drug-induced colitis, have the same pattern and require the procedure for the assessment of severity and diagnosis.

Acute & Chronic Diarrhea

Patients who complain about issues with their stool should be evaluated for acute diarrhea. If the stool and blood cultures are inconclusive, or the symptoms are persistent or getting worse despite empiric therapy, then high yield procedures should be performed.

Ablation and excision of lesions

In the treatment of early CRC, endoscopic mucosal resection is a primary method. EMR can remove more intramucosal cancers and adenomas. The procedure is for tumors larger than 2cm. For lesions, less than 2cm endoscopic submucosal dissection is necessary, but in it, the chances of perforation are high.

Treatment of Lower GI bleeding

For the treatment of Lower GI bleeding colonoscope, prepare the colon by using solutions which are polyethylene glycol-based administration via nasogastric tube or orally. At present, epinephrine injection, thermal coagulation, and metallic clip placement are the available methods. Based on the severity and lesions of bleeding, colonoscopic intervention with any of the above techniques gets initiated as the initial step in achieving homeostasis. 

Colonic Decompression 

The most common presentation of colon cancer is acute colonic obstruction, which determines the overall health of the patient. Since 1990, the colonoscope has been used for intervention with common features/practices, including self-expanding metal stents, tumor debulking, and decompression tube placement.

Dilation of Colonic Stenosis

A colonoscopy is an indication of stenotic lesions like strictures caused by IBD or anastomotic restraints. The conventional methods are balloon dilation without or with electro-incision or steroid injection.

Foreign body removal 

This removal by the procedure depends on the type of foreign body, injury to the adjacent structure, the proximity to the anus, and endoscopic and surgical expertise at the health care center.

Miscellaneous Indications

  • Isolated unexplained abdominal pain
  • Abnormal radiological examination 
  • Intraoperative and preoperative localization of colonic lesions
  • Chronic constipation

Complications of Using a Colonoscope

Trauma to the colon and its adjacent organs is rare using instruments, but various complications can occur during the procedure. Examples include peritonitis, bleeding, and appendicitis. 

The Institute of ECRI has received many reports of difficulty inserting forceps by the instrument channel of twisted instruments, delaying the procedure. Issues have occurred about blockage of the air channel because of retrograde flow of protein material in the channel during the process or inadequately rinsed disinfectant. Patient infection is prevalent from improper disinfection and cleaning procedures.

Various complications can occur if the power supply to the device gets insatiable, oxygen and suction deprivation occurs, or HEPA filtration is not working.

Worldwide, the complication rates of colonoscopes remained stable and have even declined in the past 15 years. 1. These complications include:

  • Colonoscopy with polypectomy causes
  • Post-polypectomy Perforation 
  • Post-polypectomy Bleeding

Alternative Instruments 

The use of colonoscopes requires sedation; two less common alternatives do not require this: The flexible sigmoidoscope, that exam that only a part of the colon, second, the virtual colonoscopy, involves a scan instead of a tube. However, both procedures require bowel movements before the process.

General Specification of Colonoscopes

There are different models of colonoscopes found on the US market, but these are general specifications of the device.

  • Approximate dimensions: 1700 mm
  • Approximate weight: 5 kg
  • Typical product lifetime: 4 to 5 years

Optical system:

  • Field of view: 140-170°
  • The direction of view: forward
  • Depth of field: 2-100 mm

Working Length:

  • L: 1680 mm
  • I: 1330 mm

Angulation range

  • Up: 180°
  • Down: 180°
  • Right 160°
  • Left: 160°

Total Length of an instrument

  • L: 2000-2006 mm
  • I: 1650-1655 mm

Compatible EVIS EXERA System

  • Video system center: OLYMPUS CV-190
  • Xenon light source: OLYMPUS CLV-190

How Do Colonoscopes Work?

A colonoscopy generally lasts anywhere between 30 and 60 minutes. The patient usually lies on their side on a procedure table. Before the insertion of the colonoscope, the patient should be sedated using anesthesia if they choose to be. It is important to note that this is typically the patient’s choice, and the options range from no medication to general anesthesia. 

Initially, the gastroenterologist inserts the instrument through the rectum in the colon. The scope bends to move in line with the curves of the intestine. The scope blows air in the colon to make it wider so the doctor can see a clear image of the colon. The images can be recorded, stored, or printed on digital media. 

During the procedure, if the doctor sees something abnormal, minor amounts of tissue can be removed (called a biopsy) for small analysis. When the doctor has finished, the scope should be carefully withdrawn. 

Market Leaders

Boston Scientific 

Through its subsidiaries and divisions, the company offers a wide range of products. EndoChoice FUSE colonoscopy devices are some of their colonoscopy products.

Fujifilm Holdings 

They engage in R&D, sales and services, manufacturing of various medical devices, including colonoscopes. Some of their options for instruments include slim, super slim, standard, and dual-channel with large insertion tube diameters.

HOYA Group 

The company offers a colonoscope through a division called PENTAX Medical. It offers duodenoscopes, upper GI gastroscopes, and sigmoidoscopes.

KARL STORZ 

It is a medical device manufacturing company that distributes endoscopic colonoscopy equipment in more than 38 countries.

OLYMPUS 

OLYMPUS engages in R&D activities, marketing, and manufacturing for different medical devices in Japan and worldwide.

Conclusion

The colonoscope is an instrument used to diagnose and treat the diseases of the colon. Different modifications have occurred in the tool according to the needs of the procedure (e.g., some are flexible while others have moderately hard insertion tubes). For vision, a fiber optic light bundle transmits light. The patients referred for surgical resection of a polyp preoperatively undergo colonoscopies, sparing one-third of patients from colectomy. Moreover, the operating surgeon’s repeated endoscopy allows them to confirm the position of the polyp and a colonic tattoo that facilitates laparoscopic resection.