Developing a personalised inflatable rectal obturator

Abstract

Rectal obturators like ProSpare and endorectal balloons (ERB) may reduce prostate motion during prostate radiotherapy, improving dosimetry of the target volume and surrounding healthy tissue [1-3]. ERBs are inflatable and well-tolerated, but an accumulation of gas proximal to the device can decrease its efficacy in reducing prostate motion [4]. ProSpare’s angled shape allows it to “lock in” at the anorectal angle and is made of high-impact ABS to reduce prostate motion. However, initial data from the POPS trial (NCT02978014) has shown 7/19 (37%) of patients could not insert ProSpare at their initial attempt, possibly because of the anal sphincter not stretching enough to accommodate the device. To address this issue, we present a deployable or inflatable device that becomes rigid and angled like ProSpare upon deployment, aiming to improve outcomes by reducing motion during prostate radiotherapy, while achieving good tolerance for nearly all patients. Laser welding was used to create inflatable chambers, forming ridges that provide rigidity once inflated [5]. Here, we report initial designs and validations of rigidity