When do we place a double pigtail (double pigtail stent) stent after removal of the LAMS (Lumen-Apposing Metal Stent) in cystogastrostomy?

Double Pigtail Stent Placement After LAMS Removal in Cystogastrostomy

Double pigtail plastic stents should be placed at the time of LAMS removal, typically at 4-6 weeks after initial LAMS placement, to maintain fistula tract patency and prevent closure of the cystogastrostomy. 1

Timing of LAMS Removal and Stent Exchange

The optimal timing for LAMS removal is 4-6 weeks after initial placement, once the pancreatic fluid collection has adequately resolved. 1 This timeframe allows for:

• Adequate fistula tract maturation between the collection and gastrointestinal tract 1
• Minimization of stent-related complications including food impaction, bleeding, and buried stent syndrome 1
• Prevention of delayed adverse events such as splenic artery pseudoaneurysm formation 2

The LAMS should be removed within 4 weeks according to some guidelines to specifically avoid food impaction complications, as a well-formed fistula develops within this timeframe. 1

Stent Exchange Strategy

Simultaneous exchange to double pigtail plastic stents must be performed at the time of LAMS removal - this is not optional if you want to maintain the drainage tract. 1 The technique involves:

• Placement of one or two 7 Fr double pigtail plastic stents through the established fistula tract at the time of LAMS removal 1
• This prevents fistula closure, which occurs in 20% of cases without plastic stent maintenance versus only 2.6% with proper stent maintenance 1

The guideline consensus strongly supports using plastic double pigtail stents as the standard approach for maintaining cystogastrostomy patency, with technical and clinical success rates exceeding 90%. 3

Rationale for Double Pigtail Placement

Double pigtail stents serve multiple critical functions:

• Maintain fistula tract patency long-term after LAMS removal 1
• Prevent bleeding complications by avoiding direct mucosal erosion from the relatively sharp LAMS edges into the collapsed cavity wall 2
• Lower migration rates (9% for double pigtail vs 23% for straight stents) 4
• Allow continued drainage while the cavity contracts to less than 2 cm in size 1

Ongoing Management Protocol

After double pigtail stent placement:

• Routine stent exchanges every 2-4 weeks until the cavity has contracted to less than 2 cm 1, 4
• Follow-up endoscopy at 4-6 weeks to assess for complete clearance of residual debris and fistula tract patency 1
• Continued prophylactic antibiotics covering enteric gram-negative organisms and enterococci during the post-removal period 1
• Active surveillance for recurrent collection formation, which occurs in only 2.6% with proper stent maintenance 1

Alternative Approach for Select Patients

In frail patients or those refusing a second procedure, the LAMS may be left in place permanently with acceptable outcomes, including 3-year stent patency of 86% and delayed adverse events in only 7.1% of cases. 1 However, this is a compromise approach and not the standard recommendation.

Critical Pitfalls to Avoid

• Never remove LAMS without simultaneous plastic stent placement unless you accept a 20% risk of fistula closure and recurrent collection 1
• Do not leave LAMS beyond 4-6 weeks due to increasing risk of buried stent syndrome, bleeding from pseudoaneurysm formation, and food impaction 1, 2
• Do not use metal stents as the long-term maintenance stent - plastic double pigtail stents are the evidence-based standard 3