A tubular organ resection manipulator for transurethral resection of the prostate

Transurethral resection of the prostate (TUR-P) is a common treatment for benign prostatic hyperplasia (BPH). However, the damage to the mucous membrane of the urethra leads to the complications. This paper reports a tubular organ resection manipulator for transurethral resection of the prostate which can minimize damage to the mucous membrane of the urethra using a prostate displacement mechanism and a continuous perfusion-resection mechanism. The manipulator has an arm, a cutter and a drill at the endeffector, and has 4 degrees-of-freedom: bending the arm, translating the cutter, rotating the drill and rotating the endeffector. The arm displaces the prostate, and the cutter is inserted linearly into the prostate and removes enlarged tissue by drilling. Combination of the arm and cutter enables the manipulator to remove sufficient volume of enlarged prostate through small incision on the urethra, thus minimizing the damage to the urethra. After finishing one plane cutting, the manipulator rotates its body and removes another part of the prostate gland. In performance experiments, each mechanism (bending motion, insertion, and body rotation) had high repeatability within 1.0 degree and within 0.1 mm. In phantom study, the manipulator could displace gelatin model accurately with sufficient power, and could reach and remove wide range of sample tissue (589.2 mm² in one procedure). These results showed that the manipulator can displace the prostate and remove sufficient volume of the prostate tissue through a small incision on the urethra.