In prostate cancer, radioguided surgery (RGS) is used for sentinel node biopsy (SNB) and holds potential for 99mTc-PSMA-guided surgery of lymph node metastases. Rigid laparoscopic gamma probes currently used for (robot-assisted) laparoscopic RGS procedures have limited manoeuvrability and control which restricts nodal identification. To address this a tethered laparoscopic gamma probe was developed (Lightpoint Medical Ltd). The usability and initial performance of this device were assessed in a pelvic phantom and in a porcine model.
The probe, 35 mm in length and 12 mm in diameter, was tested by 7 urologists using a 3D-printed custom-build pelvic phantom containing anatomical structures and nodal packages of clinical dimensions. To ensure accurate and reproducible gripping, three grip concepts (multi-orientation off centre, multi-orientation cross cable, and single orientation off centre) were designed specifically for use with the da Vinci Prograsp, and tested for ease of gripping and handling on a 3-ranked system. Four graphic user interfaces (GUIs) were also evaluated. The favoured grip and GUI was then evaluated in a porcine model containing 4 vials of clinically representative sentinel node volumes (0.2 ml) and 99mTc activities (range 33 - 134 kBq). Prior to surgery the vials were placed on the skin of the lower abdomen, and locations monitored by CT scanning. Manual laparoscopic surgery was performed by two urologists and 1 nuclear medicine physician tasked to identify the vials in vivo by scanning the pelvic peritoneum. Upon completion participants were asked to score the overall design on a 5-point scale.
The multi-orientation off-centre grip was favoured over the other two grip designs (average rank: 1.1 vs 2.4 vs 2.4), and considered most versatile. In the porcine study, all activity concentrations could be successfully detected. All 3 participants identified the 134 kBq vials, while the 65 and 33 kBq vials were identified by 2 and 1 participants, respectively. All 3 participants found the GUI simple and easy to interpret, and the overall design of the probe was scored as 4.2/5.
The usability studies demonstrate that the tethered laparoscopic gamma probe meets the usability requirements for manual laparoscopic and robotic prostate cancer surgery. Learnings from these studies greatly influenced the design of the probe and its GUI, and clinical studies to evaluate the performance of this probe in SNB and 99mTc-PSMA RGS of LN metastases are scheduled for 2019.
Biomedical Catalyst (BMC) SBRI Healthcare.
The Journal of urology. 2019 Apr [Epub]
Jim Adshead, Francesca Oldfield, Boris Hadaschik, Jim Adshead Wouter Everaerts, Antoni Mestre-Fusco, Miranda Newbery, Dan Elson, Maarten Ruben Grootendorst, Lluis Fumado, Nina Natascha Harke
Stevenage, United Kingdom., Chesham, United Kingdom., Essen, Germany., Leuven, Belgium., Barcelona, Spain., Knaresborough, United Kingdom., London, United Kingdom., Kunal Vyas, Chesham, United Kingdom.