An instrument comprises a handle, an articulating shaft, an end effector, and a translatable hook member. The shaft defines a side aperture, proximal to an articulating section of the shaft, through which the hook member protrudes when the hook member is translated distally. The end effector is used to form a retrogastric tunnel through blunt dissection in tissue near a patient's gastro-esophageal junction; and then to pull a gastric band through the tunnel to position the gastric band about the gastro-esophageal junction. The end effector is then used to hold a first portion of the gastric band in place while the hook member is extended distally to engage a second portion of the gastric band. The hook member may then be retracted proximally to couple the second portion of the gastric band with the first portion of the gastric band, thereby latching the gastric band in place.