Feasibility and safety of intraoperative measurement of GEJD in patients undergoing fundoplication for reflux disease has been reported previously. However the feasibility and safety of this technique in patients who may present technical difficulties for instrumentation such as achalasia patients undergoing myotomy has not been evaluated. AIM: To determine the safety and feasibility of intraoperative GEJD measurements in patients undergoing surgery for achalasia. METHODS: Six patients with manometrically confirmed achalasia (2M and 4F, 24-73 yrs), undergoing myotomy and partial fundoplication were studied by a previously described technique using a specially designed catheter with a 7cm infinitely compliant bag that was placed across the manometrically determined LES and distended at 21.5 ml/min using a Harvard pump to obtain dynamic pressure-volume curves from 0-30ml intraoperatively, at pre-myotomy, post-myotomy, and post-fundoplication. GEJD was calculated as dV/dP for 5-25ml in 5ml increments. RESULTS: All patients were successfully studied without any morbidity. In all patients the pressure volume curve shifted downward after myotomy. This shift was partially reversed after fundoplication(fig). This was especially evident at higher volumes-15, 20 and 25ml. GEJD increased and the slope of the curve decreased post-myotomy. Both measurements partially reversed post-fundoplication. These differences however, did not reach statistical significance. CONCLUSIONS: The GEJD can be safely measured intraoperatively in patients undergoing surgery for achalasia and may potentially be helpful in construction of the wrap zone in respect to its tightness. Supported by NIH DK25731 & T32DK61923