Submucosal tunnel endoscopy: Peroral endoscopic myotomy and peroral endoscopic tumor resection

Table 1 Indications and contraindications of peroral endoscopic myotomy

Indications

Absolute indications

Primary idiopathic achalasia of all types [classical (I), vigorous (II), spastic (III)] (Chicago

Classification)

Relative indications

Other hypertensive motor disorders (diffuse esophageal spasm, nutcracker or jackhammer esophagus). HRTM necessary

Failed surgical myotomy (POEM at the opposite site manly posterior POEM)

Failed pneumatic balloon dilatation

Failed previous POEM. Redo POEM at the opposite site mainly posterior POEM necessary

Advanced sigmoid type achalasia with mega esophagus (bilateral POEM may be necessary)

Children with achalasia (relative indication in experienced hands and specialized centers only)

Elderly with achalasia and comorbidities and non-surgical candidates (relative indication in experienced hands and specialized centers only)

Contraindications

Absolute contraindications

Severe cardiopulmonary disease or other serious disease

Pseudoachalasia

Failure in creating the submucosal tunnel because of severe fibrosis and adhesion

Relative contraindications

Severe esophagitis and/or very large ulcer in the lower esophagus

Recent endoscopic treatment such as EMR, ESD

POEM: Peroral endoscopic myotomy; HRTM: High resolution topographic manometry; EMR: Endoscopic mucosal resection; ESD: Endoscopic submucosal dissection.

Table 2 Issues of peroral endoscopic myotomy that need further study

TT-knife vs ERBE knife vs other knives

Posterior vs anterior myotomy vs bilateral myotomy

Selective circular vs full thickness myotomy

EndoFLIP technique vs classical tricks to evaluate adequacy of myotomy

Mucosal closure clips vs OverStitch

POEM vs LHM or surgical myotomy

GERD after POEM (treatment necessary, e.g., antireflux procedure, PPIs?)

Training system for POEM

How the risk of mishaps related to POEM can be diminished?

POEM: Peroral endoscopic myotomy; LHM: Laparoscopic Heller myotomy; GERD: Gastroesophageal reflux; PPIs: Proton pump inhibitors.

Table 3 Advantages and disadvantages of peroral endoscopic myotomy vs laparoscopic Heller myotomy

	POEM	LHM
Advantages of POEM
Myotomy length	Longer myotomy up to 25 cm	Short myotomy maximum 6 cm
	Minimally invasive method	Invasive (major surgery)
Hospitalization	Less hospitalization (1-5 d)	Longer hospitalization > 5 d
Myotomy depth	Selective circular myotomy possible	Only full-thickness myotomy
Other esophageal motility disorders	Effective for esophageal spasm, nut cracker and jackhammer esophagus	Combined laparoscopic and thoracoscopic approach is necessary to obtain equivalent myotomy
Sigmoid achalasia	Effective in all types of achalasia even in end-stage, sigmoid type (S2) achalasia with megaesophagus	Major surgery such as esophagectomy may be necessary
Elderly patients	Effective in elderly with comorbidities and contraindications	Contra indication for surgery
In failed surgical	POEM after failed surgical myotomy is effective	Redo-surgery often with high rates of failure and complications
Cost	Lower hospitalization and lower cost	Higher cost in combination to surgical procedure
GERD	Less common and lower severity. No antireflux procedure (fundoplication) necessary at the moment. Further study necessary	Fundoplication necessary and routinely performed Complications from fundoplication
	Does not preclude surgery	POEM more difficult after LHM
	Bilateral POEM possible
Disadvantages of POEM
	POEM	Surgery
Follow-up	Short follow-up (novel technique)	Longer follow-up
	POEM restricted to specialized centers	Common surgical or laparoscopic procedure overall available
Training	Difficult (no so many centers)	Overall available

POEM: Peroral endoscopic myotomy; LHM: Laparoscopic Heller myotomy; GERD: Gastroesophageal reflux.

Table 4 Complications of peroral endoscopic myotomy[58]

Common complications

Gas-related complications (minor)

Subcutaneous emphysema (31.6%)

Capno/pneumomediastinum (10%-22%)

Capno/pneumothorax (11%)

Capno/pneumoperitoneum (30.6%)[58]

Mucosal injury-perforation (mediastinal or peritoneal leak) (0.3%) (major)

Mediastinitis (insufficient data)

Peritonitis (insufficient data)

Retroperitoneal abscess (2 proved cases reported)

Pleural effusion (insufficient data)

Pneumonitis (insufficient data)

GI fistula (insufficient data)

Fever (temperature > 38 °C)

Severe postoperative pain

Rare complications

Delay postoperative bleeding (1.1%)

Hematoma within the tunnel

Submucosal infection

Mortality (0.025%) (Single death/4000 POEM cases)

POEM: Peroral endoscopic myotomy; GI: Gastrointestinal.

Table 5 Efficacy and complications of peroral endoscopic myotomy

Ref.	Patients (n)	Mean age (yr)	Eckardt score (pre/post)	LES pressure (pre/post) (mmHg)	Follow-up (mo)	Efficacy	Objective GERD evidence n (%)
Onimaru et al[12], Yokohama, Japan	300	45 (3-87)	6.13/1.33	27.3/13.4	12	98%	10%
Zhou et al[4], Fudan, China	42	44 (10-70)			2.5 (1-6)	100%
Minami et al[32], Nagasaki, Japan	28	52 (19-84)	6.7/0.7	71.2/21	16	100%	Esophagitis 39.3%
Swanström et al[65], Portland, Oregon	18	59 (22-88)	6/0	45/16.8	6	94%	Esophagitis grade 1
							28%
							+pH study
							46%
Costamagna et al[39], Rome, Italy	11	41 (23-68)	7.1/1.1	45.1/16.9	3	100%
Chiu et al[64], Hong Kong, China	16	47 (22-87)	5.5/0	43.6/29.8	3	100%	+pH study 3/15 (20%)
Hungness et al[53], Chicago, Illinois	18	38 (22-69)	7/1	19/9	63	89%	Esophagitis LA 33.3%
							A 13.3%
							B 13.3%
							C 6.7%
Von Renteln et al[60], European, CT	70	45	6.9/1	27.6/8.9	12	82%	Esophagitis 42%
							LA class
							A 29.2%
							B 12.3%
Stavropoulos et al[85], Mineola, New York	100	52	7.8/0.2	44.2/17.6	13.3	96%	17/53 (32%)
		(17-93)
Verlaan et al[37], Amsterdam, The Netherlands	10	43	8/1	20.5/6.8	3	100%	60%
							LA class
							A 30%
							B 30%

GERD: Gastroesophageal reflux.

Table 6 Indications and contraindications of peroral endoscopic tumor resection

Absolute indications

Suspected or confirmed GIST of the esophagus and gastric cardia larger than 2-3 cm and lower than 5 cm, and tumor growth on follow-up

Suspected or confirmed leiomyoma of the esophagus and gastric cardia larger than > 2-3 cm and < 5 cm

Esophageal or gastric cardia SMTs in elderly with comorbidities and non-surgical candidates completed the above criteria (only in experienced hands and specialized centers)

POET does not exclude surgery. Complete histological diagnosis possible with POET

Relative indications

Esophageal and gastric SMT more than 5 cm (full-thickness resection using submucosal tunnel technique possible) (in experienced hands and specialized centers only and within studies)

Contraindication

Suspected or proved malignancy of SMTs

GIST: Gastrointestinal stromal tumor; POET: Peroral endoscopic tumor resection; SMT: Submucosal tumor.

Table 7 Advantages and disadvantages of peroral endoscopic tumor resection vs surgery

Advantages of POET
	POET	Surgical myotomy
	Minimally invasive method	Invasive (major surgery)
Hospitalization	Less hospitalization (1-5 d)	Longer hospitalization > 5 d
	Specimen for complete histology possible
	Does not preclude surgery
Elderly patients	Effective in elderly with comorbidities and contraindications (only specialized centers)	Contra indication for surgery
Cost	Lower hospitalization and lower cost	Higher cost in combination to surgical procedure
Disadvantages of POET
	POET	Surgery
Follow-up	Short follow-up (novel technique)	Longer follow-up
POEM	POET restricted to specialized centers	Common surgical or laparoscopic procedure overall available
Training	Difficult (only few centers worldwide)	Overall available
Outcome	Complete curable resection may be not possible in malignant GIST cases	Complete resection possible

GIST: Gastrointestinal stromal tumor; POET: Peroral endoscopic tumor resection; POEM: Peroral endoscopic myotomy.

Table 8 Future perspectives of submucosal tunnel endoscopy

Endoscopic vagotomy?

Endoscopic thoracoscopy?

Endoscopic retroperitoneoscopy?

Endoscopic peritoneoscopy?

Endoscopic sympathectomy