Background and study aims: In cases where biopsies remain inconclusive, removal of mediastinal lymph nodes for
further analysis requires surgical means. Natural orifice transluminal endoscopic
surgery (NOTES) procedures allow incision/closure of the gut wall, which might enable
endoscopic excision of pre-marked nodes. The aims of the current study were to investigate
the feasibility, safety, and reproducibility of lymph node generation in an animal
model to enable endoscopic ultrasound-guided (EUS) lymph node removal (ELR) using
transesophageal NOTES access/closure and to compare this procedure with thoracoscopic
lymph node removal (TLR) in a randomized long term survival animal study.
Patients and methods: Lymph node creation using graphite injection was performed in 12 pigs. After randomization
into ELR and TLR groups, lymph nodes were marked with newly developed anchors under
EUS guidance and removed using either ELR or TLR. ELR included incision of the esophageal
wall and closure after lymph node removal. The main outcome measures were success
in lymph node generation, technical success of lymph node removal, complications,
and comparability of ELR and TLR.
Results: Generation of lymph nodes proved successful in all animals in 46 /48 sites injected
(96 %). Anchors were placed through the selected nodes in a mean of 9.4 minutes. TLR
and ELR were successful in all cases. One bleeding occurred during esophageal incision
in ELR, which was stopped endoscopically. After lymph node removal, endoscopic suturing
of the incision took a mean of 18 minutes. Procedure time was longer for ELR than
TLR (mean 48 vs. 42 minutes). All animals survived the procedures. Autopsy after 4
weeks showed two thoracic wall abscesses in the TLR group and none in the ELR group. Microscopic
analysis revealed well healed esophageal scars.
Conclusion: ELR proved to be feasible in this limited sample size and complications were not
observed more frequently in this group than in the TLR group.