Soft robotics have shown tremendous potential in helping patients with hand pathologies perform rehabilitation exercises because of the affordability and the inherent softness the soft actuators possess. To date, most of the soft actuators are fabricated with shape deposition manufacturing (SDM) method, which is time-consuming and might not be able to withstand high pressure or preserve the air tightness after multiple inflationdeflation cycles. In this paper, we present a novel monolithic fabrication method combining the advantages of lost-wax and inverse-flow-injection processes. Compared with the actuators formed with traditional fabrication methods, the actuators formed with the novel method proposed in this paper not only possess superior fabrication efficiency, but also can bear 2.5 times higher pressure, and still show advantages on the fatigue endurance testing when performed at the same pressure and frequency. Lastly, a prototyped hand rehabilitation system consisting of a soft robotic glove, an integrated control box and a concise interface are presented.