Instruments, systems, implants, and methods are provided for performing
submucosal medical procedures in a desired area of the digestive tract
using endoscopy. Instruments include a safe access needle injection
instrument, a submucosal tunneling instrument, a submucosal dissection
instrument, and a mucosal resection device. A submucosal implant device
for diagnosing and treating disorders of the body may be implanted. A
passive submucosal implant device may take the form of a drug delivery
depot in which a therapeutic agent within the depot elutes from the depot
according to a predetermined elution profile. An active submucosal
implant device may take the form of a drug delivery device that
incorporates a self-contained diagnostic system to determine the
appropriate delivery time and dosage of a therapeutic agent to be
administered.