Natural orifice translumenal endoscopic surgery (NOTES) (patient information)

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Editor-In-Chief: Mohammed A. Sbeih, M.D. [mailto:msbeih@perfuse.org] Phone:617-849-2629

Synonyms and keywords: Natural orifice translumenal endoscopic surgery, Single incision laparoscopic surgery, Minimally invasive surgery, Transanal endoscopic microsurgery, Natural orifice surgery consortium for assessment and research, Society of american gastrointestinal and endoscopic surgeons.

Overview
Natural orifice translumenal endoscopic surgery (NOTES) is an experimental surgical technique whereby abdominal and thoracic operations can be performed without any scars, or with very tiny ones. The procedure is performed through a hollow organ by passing surgical instruments and a tiny camera through a natural orifice (mouth, urethra, anus, etc.). The patients recover more quickly and experience less pain and better cosmesis. The postoperative complications such as wound infections and hernias are significantly reduced. Animal models and cadavers have been used to demonstrate that NOTES procedures are safe and feasible. Some of the NOTES applications are abdominal cavity screening, internal organs biopsy, appendectomy, cholecystectomy, tubal ligation, gastrojejunostomy, partial hysterectomy, oophorectomy, colorectal resection and trans-esophageal myotomy.

Experimental Evolution
The evolving concept of natural orifice translumenal endoscopic surgery (NOTES) combines the techniques of minimally invasive surgery with flexible endoscopy. This permits performing certain procedures endoscopically by passing the endoscope and the surgical instruments through a natural orifice, then transluminally into areas that would not otherwise be accessible endoscopically (by the commonly used endoscope).

NOTES procedures have moved quickly from a concept to a therapeutic surgical approach based on many preclinical studies. These studies have demonstrated that several types of NOTES operations can be performed in animal survival models and human cadavers. NOTES procedures have been expanded in the last few years to cover a wide range of complex surgical operations by using the right translumenal route and suitable instrumentation.

Cholecystectomy, which is a high volume and relatively simple operation, has been the focus of most early NOTES research studies. NOTES Cholecystectomy has been performed successfully on many patients.

Recently, Robotic surgery has been investigated to be applied in NOTES procedures, a miniature in vivo robot has been developed for NOTES.

Advantages
Potential advantages of NOTES over other surgical methods include the following:
 * There are faster recovery and shorter hospital stay in NOTES than laparoscopy or laparotomy procedures. Usually the patient is discharged on postoperative days 1 or 2 if the NOTES procedure has not been complicated.
 * There is less physiologic insult in NOTES procedures than laparoscopy or laparotomy procedures.
 * NOTES can avoid and minimize the potential complications of wound infections. Wound infection is a common surgical complication. Eliminating all skin incisions would eliminate the adverse impact of wound infection on the health care costs and patients' recovery.
 * NOTES Decreases the incidence of incisional hernias and postoperative adhesions.
 * Anesthesia requirements in NOTES are relatively less than other types of surgery.
 * Theoretically, NOTES causes less immunosuppression for the patient than other surgical approaches.
 * Postoperative pulmonary and diaphragmatic function are better in NOTES procedures.
 * Better cosmetic results with the potential for scarless abdominal surgery.
 * NOTES may have an advantages in specific subpopulations. It can be performed in morbidly obese patients, in whom traditional access to the peritoneal cavity can be difficult because of abdominal wall thickness, thus an easy alternative in these patients.
 * Patients usually do not need post-operative narcotic medications (analgesia). This may be due to the minimal trauma for the muscle fibers, nerves and skin by this kind of surgery.

Human Experience
Human cases that have been performed successfully include:
 * Endoscopic drainage of pseudocyst
 * Percutaneous enteral gastrostomy salvage
 * Robotic-assisted laparoscopic transvaginal nephrectomy
 * Staging for tumors
 * Transanal rectosigmoid resection for tumors
 * Transgastric appendectomy
 * Transgastric cholecystectomy
 * Transgastric debridement of necrotizing pancreatitis
 * Translumenal feeding gastrostomy
 * Transvaginal donor kidney extraction
 * Transvaginal cholecystectomy
 * Transvaginal appendectomy

NOTES Challenges and Drawbacks

 * Puncturing one of the viscera to perform the surgical procedure. This needs to be assessed thoroughly regarding the presence of long term complications.
 * Instrumentation is still inadequate to perform all NOTES procedures.
 * Costly and time consuming NOTES training sessions should be provided for surgeons and gastroenterologists before they could be able to perform NOTES procedures.
 * Cultural and geographical variations may play a roll in the decision to accept a transvaginal surgery or not.
 * It is more difficult to handle complications in NOTES compared with other approaches because of the limited space available for the NOTES instruments. This may require conversion of the procedure to be open sometimes. Beside the complications of any surgical operation (laceration, perforation and bleeding, etc.), NOTES complications may also include:
 * Injury to abdominal organs
 * Bowel perforation or injury
 * Biliary fistulae and leaks
 * Urinary incontinence
 * Fecal incontinence
 * Peritonitis


 * Financial resources are required for the technological developments and NOTES implementation.
 * In general, operative time may be longer in some NOTES procedures than the standard laparoscopic approach. Adequate instrumentation and training might shorten the time required for NOTES in the future.

Potential Applications
NOTES procedures have been performed through different natural orifices. So far, transvaginal approach is the most commonly used and has the highest success rate for certain procedures.


 * Transvaginal NOTES

Transvaginal route is the most common approach that has been used for NOTES procedures. This approach has been used for cholecystectomy, appendectomy, colon resection, abdominal wall hernia repair, and sleeve gastrectomy. Transvaginal fertility procedures and oocytes procurement transvaginally have been performed for years. Transvaginal cholecystectomy and transvaginal appendectomy have been performed in humans. There are many advantages for this approach which include:
 * The organs, such as gallbladder, appendix or others, can be extracted easily through the flexible walls of the vagina. This is considered an advantage for the large size organs.
 * It is relatively easier and safer to perform some procedures via this approach. Vaginal wall closure is less complex than gastric wall closure and has less complications rate. A single stitch can be easily used to close the incision.
 * In general, transvaginal NOTES has lower complications rate than other approaches.
 * Transvaginal rout is considered the best rout for performing minor uterine procedures for benign uterine diseases.
 * Sexual function is not affected by transvaginal extraction of the uterus or other organs.

The long-term effects of transvaginal procedures have not been investigated yet. Some of the drawbacks of this approach include:
 * It can be used only in females.
 * The NOTES surgeon should have the basics of gynecological surgery before performing a transvaginal procedure.
 * Women may present with dyspareunia and infertility after the transvaginal NOTES procedure
 * There is a potential risk for urinary tract infection after urinary bladder cannulation (required in transvaginal NOTES procedures).
 * There is a risk for injury to nearby organs. The rectum and the sigmoid colon are at higher risk than other structures.
 * Transvaginal approach may have higher incidence rates for certain complications (bladder injury and vaginal hematoma) than other surgical approaches.


 * Transanal/Transrectal NOTES

Currently, there are clinical trials that aim to assess the oncological safety of this approach in treating benign and malignant colorectal tumors. This is considered a less invasive option to perform colorectal procedures, such as resection of colonic ulcers, adenomas, and early colorectal cancers. Fecal incontinence may result from the pressure on the anal sphincter by the platform during performing the procedure. Studies have demonstrated that there is no higher risk of infection or peritonitis by entering into the peritoneal cavity via a transcolonic/transanal puncture in the presence of adequate closure for the colotomy.


 * Transgastric NOTES

This NOTES approach is more sophisticated than the transvaginal route, especially in terms of gastric wall closure after extracting the organ (requires laparoscopic assistance). Also, the complication rate is higher in this approach compared with the transvaginal route. Appendectomy, cholecystectomy and cancer staging have been performed by this approach. Retrieval of dislodged endoscopic gastrostomy tube via this approach has been reported as well. however, all cases require some degree of hybridization (laparoscopic assistance) which is required for most transgastric NOTES procedures. This approach can be used in all patients regardless their gender but the extracted specimen (through the oral cavity) needs to be relatively smaller than those extracted by other routs. Peritonitis and esophageal rupture may occur after transgastric procedures. In general, complications are more common in transgastric procedures than in transvaginal procedures.


 * Transesophageal NOTES

This approach can be used for the treatment of achalasia (failure of relaxation of the lower esophageal sphincter that causes difficulty in swallowing). Many cases of per oral endoscopic myotomy (POEM) have been performed successfully to treat achalasia. Esophageal injuries could be prevented during performing the procedure by using gastroesophageal overtubes. Interventions include mediastinoscopies, thoracic organs biopsy, and epicardial operations. Usually, conventional flexible endoscopes and other instruments are used to perform the procedure.


 * Transurethral/Transcystic NOTES

Some procedures can be performed through the urethra or the urinary bladder. Transurethral resection of the prostate (TURP)is a urological operation to treat benign prostatic hyperplasia (BPH). As the name indicates, it is performed by visualising the prostate through the urethra and removing tissue by electrocautery or sharp dissection. This is considered the most effective treatment for benign prostatic hyperplasia (BPH). Outcome is considered excellent for 80-90% of BPH patients. This approach has been used to perform percutaneous needle biopsy of tumors of intraabdominal organs and retroperitoneal structures. Ovarian follicles aspiration has been performed using the transcystic approach.