What is the incidence of pneumothorax in patients undergoing Peroral Endoscopic Myotomy (POEM)?

Incidence of Pneumothorax in Patients Undergoing POEM

The incidence of pneumothorax in patients undergoing Peroral Endoscopic Myotomy (POEM) ranges from 1.5% to 17%, with most cases being clinically insignificant and requiring intervention in only about 5.6% of patients. 1, 2

Pneumothorax Rates in POEM Procedures

POEM has emerged as an effective minimally invasive treatment for achalasia with high success rates (>90%). However, like any procedure, it carries risks of complications including pneumothorax:

• A systematic analysis of 1680 POEM procedures reported pneumothorax in 1.5% of patients (95% CI 1.0%-2.2%) 1
• Another study examining CT findings after POEM found pneumothorax in 17% of patients, though only 5.6% required intervention 2
• A smaller study of 119 cases reported pneumothorax occurring during the operation in 2.5% of patients and postoperatively in 25.2% 3

Risk Factors for Pneumothorax

Several factors have been identified that increase the risk of pneumothorax during POEM:

• Use of air insufflation instead of CO2 (OR 3.41,95% CI 1.37-8.50) 1
• Institutional experience less than 1 year (OR 3.85,95% CI 1.49-9.95) 1
• Increasing patient age 2
• Presence of mucosal edema (OR 2.01,95% CI 1.14-3.53) 1

Management of Pneumothorax After POEM

Most pneumothoraces detected after POEM are clinically insignificant and resolve spontaneously:

• Of patients with pneumothorax detected on CT, only 17 of 50 (34%) required intervention 2
• Management is typically conservative with observation for asymptomatic cases
• Intervention (typically chest tube placement) is required for symptomatic cases or tension pneumothorax 4

Routine Post-POEM Imaging

The value of routine post-procedure CT imaging has been questioned:

• A study of 58 patients found that CT esophagograms revealed clinically meaningful adverse events requiring management changes in only 14% of patients, all of whom had clinical symptoms prior to imaging 5
• Routine chest CT scanning after POEM is probably not warranted due to the high rate of minor and clinically irrelevant findings 2

Prevention of Pneumothorax

Several measures can reduce the risk of pneumothorax during POEM:

• The use of CO2 insufflation instead of air is obligatory to reduce related adverse events 2
• Procedures should be performed by experienced physicians in high-volume centers (20-40 procedures needed to achieve competence, 60 to achieve mastery) 6
• After implementing CO2 insufflation, the major adverse event rate declined to 1.9% and plateaued at approximately 1% after 3.5 years of institutional experience 1

Other Common Complications of POEM

While pneumothorax is important, other complications are also observed:

• Pleural effusion (34-66%) 2, 5
• Subcutaneous emphysema (28-55.5%) 2, 3
• Pneumomediastinum (29.4-78%) 3, 5
• Pneumoperitoneum (37-91%) 2, 5
• Gastroesophageal reflux (41-58%) 6

Most of these complications are self-limiting and can be managed conservatively without additional interventions.