NOTES ("natural orifice transluminal endoscopic surgery") is a technique of minimally invasive surgery that uses only natural body openings such as the mouth, vagina, or rectum as a portal to the interior of the body to reduce access trauma. When the NOTES technique is combined with other methods (e.g., NOTES + classical laparoscopy or SILS), it is referred to as Hybrid-NOTES technique or NOSE ("natural orifice specimen extraction"), where only individual surgical steps are performed via the NOTES access, such as the insertion of a stapling device or the retrieval of a specimen. Otherwise, the procedure in the hybrid technique is carried out as is customary in conventional laparoscopy. The main advantages of both techniques are reduced postoperative pain, faster recovery, fewer wound complications, and incisional hernias [4, 10, 12, 14].
The term NOTES was coined by Antonie Kallo from Baltimore in 2004 for a transgastric peritoneoscopy [6]. The first transvaginal cholecystectomy in humans was published as a case report in 2007 [11]. In the same year, Zornig et al. described the first transvaginal cholecystectomy with rigid instrumentation in hybrid NOTES technique in Germany [16] and reported a series of 20 patients the following year [15]. The first NOTES sigmoidectomy was performed in 2007 by Whiteford et al. on a cadaver model [13]. In 2009, Leroy et al. reported on a combined transgastric and transanal NOTES sigmoidectomy on a pig that survived the procedure [9].
NOTES Databases
NOTES surgery, which requires only a shallow learning curve for experienced laparoscopists, developed from animal models to clinical application within a few years. Online databases such as the "German Registry for Natural Orifice Transluminal Endoscopic Surgery (GNR)" or the "EURO-NOTES Clinical Registry for Natural Orifice Transluminal Endoscopic Surgery (ECR)" [1] were established, where clinics can enter their results and contribute to the safe implementation of NOTES techniques. The national NOTES registry of the German Society for General and Visceral Surgery (DGAV) currently includes 4270 patients (as of 14.01.2017).
Transgastric and Transvaginal NOTES Technique
The transgastric NOTES technique has now been abandoned. Reasons include problems with maintaining the pneumoperitoneum and retrieving larger specimens through the esophagus. The secure closure of the gastrostomy, which is associated with potentially high morbidity, is particularly problematic [2]. In a literature review from 2012, Coomber et al. reported on 61 patients who underwent a transgastric procedure (35 cholecystectomies and 26 appendectomies). With 24% after cholecystectomy and 21.4% after appendectomy, morbidity was far above the 4-10% after classical laparoscopic surgery [5].
The majority of NOTES procedures are transvaginal, which, in contrast to transgastric procedures, have a solid safety profile [2]. The colpotomy and the insertion of instruments are performed under vision, and transvaginal gynecological procedures in the small pelvis, which have been performed for over 120 years, show that infections and hernias are very rare. The stretchability of the vaginal wall allows for the insertion of instruments with a larger diameter as well as the retrieval of larger specimens [3].
Technical Aspects of Hybrid-NOTES Sigmoid Resection
The range of transvaginal NOTES procedures includes cholecystectomy, appendectomy, nephrectomy, sigmoidectomy, and now also splenectomies, liver resections, and sleeve gastrectomy in obesity surgery [5]. According to the national NOTES registry of the German Society for General and Visceral Surgery (DGAV), in 2015, nearly 88% of the procedures involved gallbladder diseases [8].
Although colon resections are less frequently performed using the NOTES technique, numerous German clinics have applied the NOTES concept to elective sigmoid resection for diverticulitis, hemicolectomies, and anterior rectal resections for colorectal carcinoma, where the actual preparation is performed classically laparoscopically or in SILS technique, and the specimens are retrieved through natural body openings (transvaginal, less frequently transrectal) [8].
In NOTES sigmoid resection, three surgical variants are distinguished:
- Vaginal retrieval with extracorporeal anastomosis preparation
- Vaginal retrieval with intracorporeal anastomosis preparation
- Transrectal retrieval with intracorporeal anastomosis preparation
The intra-abdominal, laparoscopic sigmoid preparation is the same for all surgical variants.
1. Vaginal Retrieval with Extracorporeal Anastomosis Preparation
Extracorporeal anastomosis preparation requires transvaginal luxation of the colon, making complete mobilization of the left colonic flexure mandatory. Using a transvaginally introduced linear stapler, the rectum is transected, and the resected specimen is luxated transvaginally using a clamp. At the proximal resection margin of the descending colon, the marginal arcade is ligated, and the colon is transected after applying a purse-string clamp. The pressure plate is tied in with a purse-string suture, and the descending colon is relocated intra-abdominally. After closure of the colpotomy, the mechanical descendorectostomy is performed in the usual manner.
2. Vaginal Retrieval with Intracorporeal Anastomosis Preparation
Mobilization of the left flexure is only performed if necessary. After sigmoid preparation, the rectum is transected as in the aforementioned variant. After intracorporeal transection of the marginal arcade of the descending colon, the colon is opened slightly distal to the planned resection margin antimesenterically, and the transvaginally introduced pressure plate is positioned intraluminally with the spike first. The spike is executed antimesenterically about 5 to 7 cm before the planned resection line. The colon is transected just distal to the pressure plate using a transvaginally introduced linear stapler. After retrieval of the specimen and closure of the colpotomy, the side-to-end descendorectostomy is performed.
3. Transrectal Retrieval with Intracorporeal Anastomosis Preparation
Standard mobilization of the left flexure is not mandatory in this variant either. A 12 mm trocar in the right lower abdomen is required as a stapler access. The rectum is opened about 2 cm proximal to the intended resection line using scissors before the transanally introduced pressure plate is advanced into the free abdominal cavity with a grasping forceps. The plate is introduced into the descending colon as described under 2. After stapler transection of the descending colon, the resected specimen is extracted transrectally. The open rectum is closed with the stapler. The 1 to 2 cm wide transected segment is deposited in a retrieval bag and extracted from the abdominal cavity via the 12 mm trocar access. After closure of the trocar access, the side-to-end descendorectostomy is performed.
Significance of NOTES Techniques in Elective Sigmoid Resection
The joint Sk2 guideline on diverticular disease/diverticulitis of the German Society for Gastroenterology, Digestive and Metabolic Diseases (DGVS) and the German Society for General and Visceral Surgery (DGAV) from 2014 evaluates the NOTES techniques in elective sigmoid resection as follows [7]:
Single-port, NOS, and NOTES techniques in sigmoid resection for diverticular disease are documented in terms of their technical feasibility. The significance of these techniques compared to laparoscopic techniques is unclear and should be investigated in clinical studies.
Consensus strength: Strong consensus
Comparative studies at a high evidence level are not available, so an adequate comparative assessment of the different techniques is not possible here. However, it is generally accepted that new techniques should be tested in clinical studies, ideally in comparison with conventional laparoscopic techniques […].