Status of access and closure techniques for NOTES

Clinical applications of submucosal endoscopy

PURPOSE OF REVIEW

Submucosal endoscopy with mucosal flap (SEMF), a new diagnostic and therapeutic intervention of flexible endoscopy, has been examined from the perspective of developmental laboratory work, procedural details, and results of early clinical experiences.

RECENT FINDINGS

Diagnostic natural orifice translumenal endoscopic surgery (NOTES) procedures, endolumenal achalasia myotomy, and submucosal tumor excision have been clinically performed with a SEMF method. The outcomes of these procedures were equivalent to standard surgery but with reduced morbidity. Some were accomplished under conscious sedation within the endoscopy unit.

SUMMARY

The SEMF procedure was originally developed to provide safe access to the peritoneal cavity for NOTES procedures. In the SEMF method, the submucosal layer is endoscopically tunneled and the resultant space is used as an endoscopic path into deeper layers of the gut wall and an offset exit to the peritoneal cavity. Key to the method is the overlying mucosa which serves as a sealant flap minimizing the risk of soiling a body cavity with lumenal contents and the ease by which the entry point into the submucosal working space can be closed. Positive outcomes of the early SEMF clinical experiences validate that the submucosa can be transformed into a promising novel working space for flexible endoscopy.

Single-incision laparoscopic surgery - current status and controversies

Scarless surgery is the Holy Grail of surgery and the very raison d’etre of Minimal Access Surgery was the reduction of scars and thereby pain and suffering of the patients. The work of Muhe and Mouret in the late 80s, paved the way for mainstream laparoscopic procedures and it rapidly became the method of choice for many intra-abdominal procedures. Single-incision laparoscopic surgery is a very exciting new modality in the field of minimal access surgery which works for further reducing the scars of standard laparoscopy and towards scarless surgery. Natural orifice translumenal endoscopic surgery (NOTES) was developed for scarless surgery, but did not gain popularity due to a variety of reasons. NOTES stands for natural orifice translumenal endoscopic surgery, a term coined by a consortium in 2005. NOTES remains a research technique with only a few clinical cases having been reported. The lack of success of NOTES seems to have spurred on the interest in single-incision laparoscopy as an eminently doable technique in the present with minimum visible scarring, rendering a ‘scarless’ effect. Laparo-endoscopic single-site surgery (LESS) is, a term coined by a multidisciplinary consortium in 2008 for single-incision laparoscopic surgery. These are complementary technologies with similar difficulties of access, lack of triangulation and inadequate instrumentation as of date. LESS seems to offer an advantage to surgeons with its familiar field of view and instruments similar to those used in conventional laparoscopy. LESS remains a evolving special technique used successfully in many a centre, but with a significant way to go before it becomes mainstream. It currently stands between standard laparoscopy and NOTES in the armamentarium of minimal access surgery. This article outlines the development of LESS giving an overview of all the techniques and devices available and likely to be available in the future.

NOTES: The question for minimal resection and sentinel node in early gastric cancer

Surgical therapy for gastric cancer involves both removal of the cancer lesion and complete lymph node dissection. Natural orifice transluminal endoscopic surgery (NOTES) is considered to represent the next revolution in surgery. Many surgeons and endoscopists believe that NOTES may be a superior alternative for early gastric cancer treatment. Sentinel node (SN) navigation surgery for gastric cancer: Single institution results of SN mapping for early gastric cancer are increasingly being considered acceptable. Furthermore, a major large-scale clinical trial of SN mapping for gastric cancer has recently been completed by The Japan Society of SN Navigation Surgery study group. They reported false negative rate of 7.0% while the sensitivity of metastasis detection based on SN status was 93%. Combination of SN biopsy and NOTES: This concept was first described by Cahill et al who proved the feasibility of lymphatic mapping and SN biopsy by NOTES. Lymphatic channel filling was immediately observable via the intraperitoneal optics. Partial resection of the stomach by hybrid NOTES: Several centers have already reported gastrectomy assisted by NOTES using the transvaginal route. However, the main problem of full-thickness resection of gastric wall remains endoscopic gastric closure. Establishing an endoscopic suturing method would be an important step toward expanding potential indications. NOTES is met with both enthusiasm and skepticism but will gain its own place as human creativity eventually provides solutions to its technical limitations. In the near future, NOTES can evolve the capacity to complement the existing armamentarium for gastric cancer surgery.

NOTES new frontier: Natural orifice approach to retroperitoneal disease

AIM: To develop a pure transvaginal access to the retroperitoneum, that is simple, reproducible and uses endoscopic material available on the market.

METHODS: From February 2008 to April 2009, 31 pigs were operated on, with 17 as an acute experiment and 14 with a survival protocol. The animals were placed in a supine position and a 12-mm double-channel endoscope (Karl Storz™, Tuttlingen) was used for vision and dissection. During the same time period, the access experiment was reproduced on 3 human cadavers using material similar to that used in the animal model.

RESULTS: In the animal model, 37 interventions were done on the kidney, adrenal gland and pancreas. The mean time to fashion the access was 10 min (range 5 to 20 min). No intraoperative death was observed. Two major (5%) intraoperative complications occurred: one hemorrhage on the aorta and one tearing of the right renal vein. Peritoneal laceration was encountered in 5 cases without impairing the planned task. In the survival group, good clinical outcome was observed at a mean follow-up of 3 wk (range 2 to 6 wk). In the 3 cadavers, access was performed correctly. The mean time to fashion the access was 52 min (range 40 to 60 min). All the anatomical landmarks described in the pig model were clearly identified in the same sequence.

CONCLUSION: A retroperitoneal natural orifice translumenal surgical transvaginal approach is feasible in both animal and human models and allows performance of a large panel of interventions.