Steerable DROP-IN radioguidance during minimal-invasive non-robotic cervical and endometrial sentinel lymph node surgery

Abstract

Purpose: The recently introduced tethered DROP-IN gamma probe has revolutionized the way robotic radioguided surgery is performed, fully exploiting the nature of steerable robotic instruments. Given this success, the current first-in-human study investigates if the DROP-IN can also provide benefit in combination with steerable non-robotic instruments during conventional laparoscopic surgery, showing equivalence or even benefit over a traditional rigid gamma probe.

Methods: The evaluation was performed in ten patients during laparoscopic cervical (n = 4) and endometrial (n = 6) cancer sentinel lymph node (SLN) procedures. Surgical guidance was provided using the hybrid, or bi-modal, SLN tracer ICG-^99mTc-nanocolloid. SLN detection was compared between the traditional rigid laparoscopic gamma probe, the combination of a DROP-IN gamma probe and a steerable laparoscopic instrument (LaproFlex), and fluorescence imaging.

Results: The gynecologists experienced an enlarged freedom of movement when using the DROP-IN + LaproFlex combination compared to the rigid laparoscopic probe, making it possible to better isolate the SLN signal from background signals. This did not translate into a change in the SLN find rate yet. In both cervical and endometrial cancer combined, the rigid probe and DROP-IN + LaproFlex combination provided an equivalent detection rate of 96%, while fluorescence provided 85%.

Conclusion: We have successfully demonstrated the in-human use of steerable DROP-IN radioguidance during laparoscopic cervical and endometrial cancer SLN procedures, expanding the utility beyond robotic procedures. Indicating an improved surgical experience, these findings encourage further investigation and consideration on a path towards routine clinical practice and improved patient outcome.

Trial registration: HCB/2021/0777 and NCT04492995; https://clinicaltrials.gov/study/NCT04492995.

Keywords: Cervical cancer; Endometrial cancer; Laparoscopic surgery; Radioguided surgery; Sentinel lymph node; Steerable instruments.

Fig. 1

Overview of laparoscopic gamma probe applications investigated in this study. A Traditional rigid laparoscopic gamma probe, displaying available movement and intraoperative application. B DROP-IN probe usage with steerable laparoscopic instruments (i.e., DROP-IN + LaproFlex combination), displaying increased availability of movement and intraoperative application

Fig. 2

Preoperative sentinel lymph node mapping using nuclear imaging. A SPECT/CT imaging in cervix cancer, showing the sentinel node locations on a surface render overview (left) and detailed axial slices (middle and right). B SPECT/CT imaging in endometrial cancer, showing the sentinel node locations on a surface render overview (left) and detailed axial slices (middle and right)

Fig. 3

Workflow hybrid sentinel lymph node surgery with DROP-IN and fluorescence guidance for various surgical settings. A Surgical planning. B, C Preparation of the surgical instruments. D OR overview. E DROP-IN probe pick-up and guidance

Fig. 4

Fluorescence guidance during the hybrid sentinel node procedures in cervix and endometrial cancer. A Laparoscopic surgery with the Karl Storz fluorescence camera system. B Laparoscopic surgery with the Stryker Pinpoint fluorescence imaging system

Fig. 5

Differences in the traditional laparoscopic operating room versus robotic operating room. A In the traditional laparoscopic setting, trocar placement is less restricted than in the robotic setting. If the size of the trocars used permits it, this could allow for gamma probe insertion at various points of entrance in to the patient. B In the robotic setting, most trocars are in permanent use by the robot, limiting probe access to the assistant trocar only. C Schematic overview of DROP-IN probe maneuverability with rigid laparoscopic instruments. D Schematic overview of DROP-IN probe maneuverability with robotic instruments