Sa1324 IS THERE A ROLE OF RETROGRADE MYOTOMY AS AN ALTERNATIVE TO ANTEGRADE MYOTOMY IN PER ORAL ENDOSCOPIC MYOTOMY (POEM) FOR ACHALASIA CARDIA? - A FEASIBILITY ASSESSMENT STUDY AMONG BEGINNERS IN THIRD SPACE ENDOSCOPY

Abstract

Antegrade approach is the usual mode of performing myotomy in POEM for achalasia cardia. Although there are reports of retrograde approach, however, its applicability especially among the beginners is uncertain. We assessed the feasibility of retrograde approach as an alternative to antegrade approach among beginners in third space endoscopy. We did a retrospective review of our prospectively maintained database of patients who had undergone POEM for achalasia cardia. After the first 20 cases, we divided them into 2 groups: antegrade and retrograde myotomy. The antegrade myotomy was done in the usual standard fashion by starting 2-3 cm distal to the incision site and proceeding in forward direction till we reach the end of the tunnel while the retrograde myotomy was done by starting at the distal end of the tunnel and completing the myotomy by withdrawing the scope in a reverse fashion till a point marked 2-3 distal to the incision site. We compared the difference in the time needed to perform complete myotomy and noted the advantages and disadvantages with retrograde myotomy. After the first 20 cases of POEM, we did 6 retrograde myotomies among the next 24 cases with 2 anterior and the rest 4 posterior myotomies and rest 18 were standard antegrade approach. The mean myotomy time for antegrade approach was 20 min (range8-40min) while the mean time for retrograde myotomy was 28 min (range 15-50 min) (p=0.074). The mean length of myotomy in antegrade approach was 8.4 cm (range 6-13 cm) while the mean length for retrograde approach was 7.1 cm (range 6-9 cm) (p=0.119). The following were the problems faced with retrograde myotomy- 1)- difficulty in visualizing the straight axis of myotomy leading to deviation (Figure 1) , 2) conversion to antegrade approach in 2 cases (both posterior) because of the difficulty in maintaining the orientation of the scope while performing myotomy especially with thick muscle, 3) added strain on the limb holding the scope in twisted position in posterior myotomy, 4) incomplete myotomy necessitating to take the scope repeatedly back and forth to dissect the left over fibres, 5) difficulty in visualizing the depth of myotomy, 6) need to always go antegrade to complete the distal end of myotomy, 7) marking the straight axis from distal end to the proximal marked point by giving burst of spray coagulation could avoid deviation of axis but still couldn’t avoid the strain on the limb holding the scope in twisted position, 8) chance of injury to lung in posterior approach and pericardium in antegrade approach. Due to these problems we stopped performing this approach in subsequent cases. Antegrade approach remains the preferred approach while retrograde doesn't have any added advantage.