To perform the ESD safely, it is necessary to create and expand a potential submucosal space to allow dissection between the mucosa and muscle wall. This is done via submucosal injection and reduces the risk of perforation and transmural thermal injury by separating the lesion of interest from the deeper muscularis propria layer and decreases tissue resistance within the transection plane [2]. The first injections are made around the perimeter of the lesion to provide a margin of safety when incising the mucosa; subsequent injections are made beneath the lesion during submucosal dissection.

The submucosal injection should be performed in such a way that the lesion is elevated into the lumen to improve exposure and visualization of the margins. If the polyp is situated on a fold, the first submucosal injection site should be along the proximal margin of the lesion to allow the polyp to fall forward into view. If the submucosal injection is started along the distal portion of the polyp, there is a danger of the polyp falling backward away from the view of the scope, which increases the difficulty of ESD. To create the submucosal cushion, the needle tip is advanced into the mucosa while the assistant starts injecting. As the needle tip advances into the submucosal space, there is an immediate elevation of the mucosa, confirming entry into the correct plane. If the lesion does not lift or the injectate extravasates intraluminally, the needle can be gently repositioned until the correct plane is entered. Failure of polyps to lift adequately despite appropriate injection technique (the “non-lifting sign”) may indicate the presence of invasive disease requires surgical resection. Non-lifting may also occur as a result of fibrosis from previous polypectomy attempts.

The ideal injection agent should be safe and inexpensive and provide a long-lasting submucosal cushion. The two common elements in the various injection solutions are the colloid (hyperosmolar) solution and an inert dye (like indigo carmine or methylene blue). Several agents have been used for lifting during ESD and each has its own limitations reflecting the absence of a clearly superior solution (Table 16.2). Commonly, ESD solutions contain normal saline, glycerol, and hyaluronic acid. Hypertonic saline solution and dextrose have been noted to cause local tissue damage and were abandoned. Sodium hyaluronate 0.4% (MucoUp; Johnson and Johnson, Tokyo, Japan) is widely reported in the Asian literature but is expensive [4]. Alternatively, hydroxypropyl methylcellulose (Hypromellose) diluted six to eight times with saline can be used and is relatively inexpensive (Fig. 16.2). Injectates are colored with a few drops of dye (typically indigo carmine or methylene blue) to improve visualization and facilitate differentiation of tissue planes [8].

Injectates are typically delivered with a 21- to 25-gauge injection needle catheter while viscous injectates require a larger bore needle. Some ESD knives have an integrated water jet channel within the device catheter. The Hybrid Knife (ERBE, Tuebingen, Germany), the only integrated device currently available in the United States, features an ultrafine water jet powered by a foot pedal that is powerful enough to penetrate the mucosal layer in a needleless fashion for lifting purposes.

Electrocautery facilitates polyp removal by tissue cutting (snare closure) and coagulation (thermal energy). Cautery energy applied at the cellular level produces heat due to tissue resistance which leads to tissue disruption or coagulation with hemostasis, depending on the chosen waveform. A variety of instruments can be used with electrocautery including probes, snares, forceps, and knives. Monopolar devices transmit current from an electrode in the instrument’s tip through the patient’s body to a remote grounding plate (usually on the leg or thigh) to complete the circuit. Bipolar devices have both active and return electrodes in the instrument tip obviating the need for a grounding plate. Each of the following tools is best used for specific steps and maneuvers (Fig. 16.3) [9]:

A variety of snares are available for use in advanced endoscopic resection techniques. The choice of a specific snare is influenced by lesion size, morphology, and location and personal preference (Fig. 16.4). While EMR techniques mainly involve polyp removal with snare or strip biopsy, the hybrid ESD technique uses a circumferential mucosal incision followed by en bloc resection of the lesion with snare (see Video 16.1). This technique can be considered a bridge between EMR and ESD. When lesions are difficult to access via the mucosal plane, hybrid ESD may achieve better results than EMR [10].

ESD involves several basic steps (Fig. 16.5). First, the lesion is delineated, although marking the borders in the colon and rectum is usually not necessary (Fig. 16.6). After submucosal injection, a circumferential incision is created beginning at the proximal border. Once half of the circumference is incised, submucosal dissection is performed in this half of the circumference. In some cases, retroflexion may be necessary to complete this step. The circumferential incision is then completed and the submucosa is completely dissected from the distal side. Surgeon may use one or more different types of endoknife combinations during the procedure. The resected lesion is retrieved following complete dissection (Fig. 16.7). Bleeding encountered during dissection should be coagulated immediately and potential perforations should be closed using endoclips.