Publications by authors named "S Duke Herrell"

114 Publications

Patient-specific, touch-based registration during robotic, image-guided partial nephrectomy.

World J Urol 2021 Jun 16. Epub 2021 Jun 16.

Department of Urology, Vanderbilt Institute for Surgery and Engineering (VISE), Vanderbilt University Medical Center, Nashville, TN, USA.

Image-guidance during partial nephrectomy enables navigation within the operative field alongside a 3-dimensional roadmap of renal anatomy generated from patient-specific imaging. Once a process is performed by the human mind, the technology will allow standardization of the task for the benefit of all patients undergoing robot-assisted partial nephrectomy. Any surgeon will be able to visualize the kidney and key subsurface landmarks in real-time within a 3-dimensional simulation, with the goals of improving operative efficiency, decreasing surgical complications, and improving oncologic outcomes. For similar purposes, image-guidance has already been adopted as a standard of care in other surgical fields; we are now at the brink of this in urology. This review summarizes touch-based approaches to image-guidance during partial nephrectomy, as the technology begins to enter in vivo human evaluation. The processes of segmentation, localization, registration, and re-registration are all described with seamless integration into the da Vinci surgical system; this will facilitate clinical adoption sooner.
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http://dx.doi.org/10.1007/s00345-021-03745-yDOI Listing
June 2021

Differential effect of body mass index by gender on oncological outcomes in patients with renal cell carcinoma.

J Cancer Res Ther 2021 Apr-Jun;17(2):420-425

Department of Urologic Surgery, Vanderbilt University Medical Center, Nashville, TN, USA.

Objectives: To investigate the relationship between gender, body mass index (BMI), and prognosis in renal cell carcinoma (RCC) patients.

Materials And Methods: We retrospectively reviewed 1353 patients with RCC who underwent a partial or radical nephrectomy between 1988 and 2015. The association among sex, BMI, stage, grade, overall survival (OS), and recurrence-free survival (RFS) was analyzed.

Results: The median age of the patients was 59.4 ± 11.9 years. Female patients had proportionally lower grade tumors than male patients (Grade I-II in 75.5% vs. 69.3% in women and men, respectively, P = 0.022). There was no relationship between Fuhrman grade and BMI when substratified by gender (p > 0.05). There was a nonsignificant trend toward more localized disease in female patients (p = 0.058). There was no relationship between T stage and BMI when stratified by gender (p > 0.05). Patients with higher BMI had significantly better OS (p = 0.0004 and P = 0.0003) and RFS (P = 0.0209 and P =0.0082) whether broken out by lower 33 or 25 percentile. Male patients with higher BMI had significantly better OS and RFS rates. However, there was no relationship between BMI and OS or RFS for female patients (P > 0.05). Multivariate analysis of the entire cohort demonstrated that a BMI in the lower quartile independently predicts OS (hazard ratio 1.604 [95% confidence interval: 1.07-2.408], P = 0.022) but not RFS (P > 0.05). When stratified by gender, there was no relationship between BMI and either OS or RFS (P > 0.05).

Conclusions: Increasing BMI was associated with RCC prognosis. However, the clinical association between BMI and oncologic outcomes may be different between men and women.
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http://dx.doi.org/10.4103/jcrt.JCRT_546_18DOI Listing
June 2021

Mechatronic Design of a Two-Arm Concentric Tube Robot System for Rigid Neuroendoscopy.

IEEE ASME Trans Mechatron 2020 Jun 27;25(3):1432-1443. Epub 2020 Feb 27.

Department of Mechanical Engineering at Vanderbilt University, Nashville, TN 37235, USA.

Open surgical approaches are still often employed in neurosurgery, despite the availability of neuroendoscopic approaches that reduce invasiveness. The challenge of maneuvering instruments at the tip of the endoscope makes neuroendoscopy demanding for the physician. The only way to aim tools passed through endoscope ports is to tilt the entire endoscope; but, tilting compresses brain tissue through which the endoscope passes and can damage it. Concentric tube robots can provide necessary dexterity without endoscope tilting, while passing through existing ports in the endoscope and carrying surgical tools in their inner lumen. In this paper we describe the mechatronic design of a new concentric tube robot that can deploy two concentric tube manipulators through a standard neuroendoscope. The robot uses a compact differential drive and features embedded motor control electronics and redundant position sensors for safety. In addition to the mechatronic design of this system, this paper contributes experimental validation in the context of colloid cyst removal, comparing our new robotic system to standard manual endoscopy in a brain phantom. The robotic approach essentially eliminated endoscope tilt during the procedure (17.09° for the manual approach vs. 1.16° for the robotic system). The robotic system also enables a single surgeon to perform the procedure - typically in a manual approach one surgeon aims the endoscope and another operates the tools delivered through its ports.
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http://dx.doi.org/10.1109/tmech.2020.2976897DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7971161PMC
June 2020

Transurethral Anastomosis after Transurethral Radical Prostatectomy: A Phantom Study on Intraluminal Suturing With Concentric Tube Robots.

IEEE Trans Med Robot Bionics 2020 Nov 29;2(4):578-581. Epub 2020 Oct 29.

Department of Mechanical Engineering, Vanderbilt University.

Current surgical approaches to radical prostatectomy are associated with high rates of erectile dysfunction and incontinence. These complications occur secondary to the disruption of surrounding healthy tissue, which is required to expose the prostate. The urethra offers the least invasive access to the prostate, and feasibility has been demonstrated of enucleating the prostate with an endoscope using Holmium laser, which can itself be aimed by concentric tube robots. However, the transurethral approach to radical prostatectomy has thus far been limited by the lack of a suitable means to perform an anastomosis of the urethra to the bladder after prostate removal. Only a few intraluminal anastomotic devices currently exist, and none are small enough to pass through the urethra. In this paper we describe a new way to perform an anastomosis in the small luminal space of the urethra, harnessing the dexterity and customizability of concentric tube manipulators. We demonstrate a successful initial proof-of-concept anastomosis in an anthropomorphic phantom of the urethra and bladder.
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http://dx.doi.org/10.1109/tmrb.2020.3034735DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7694552PMC
November 2020

Accuracy of Touch-Based Registration During Robotic Image-Guided Partial Nephrectomy Before and After Tumor Resection in Validated Phantoms.

J Endourol 2021 03 11;35(3):362-368. Epub 2020 Nov 11.

Department of Urology, Vanderbilt University Medical Center, Nashville, Tennessee, USA.

Image-guided surgery (IGS) allows for accurate, real-time localization of subsurface critical structures during surgery. No prior IGS systems have described a feasible method of intraoperative reregistration after manipulation of the kidney during robotic partial nephrectomy (PN). We present a method for seamless reregistration during IGS and evaluate accuracy before and after tumor resection in two validated kidney phantoms. We performed robotic PN on two validated kidney phantoms-one with an endophytic tumor and one with an exophytic tumor-with our IGS system utilizing the da Vinci Xi robot. Intraoperatively, the kidney phantoms' surfaces were digitized with the da Vinci robotic manipulator via a touch-based method and registered to a three-dimensional segmented model created from cross-sectional CT imaging of the phantoms. Fiducial points were marked with a surgical marking pen and identified after the initial registration using the robotic manipulator. Segmented images were displayed via picture-in-picture in the surgeon console as tumor resection was performed. After resection, reregistration was performed by reidentifying the fiducial points. The accuracy of the initial registration and reregistration was compared. The root mean square (RMS) averages of target registration error (TRE) were 2.53 and 4.88 mm for the endophytic and exophytic phantoms, respectively. IGS enabled resection along preplanned contours. Specifically, the RMS averages of the normal TRE over the entire resection surface were 0.75 and 2.15 mm for the endophytic and exophytic phantoms, respectively. Both tumors were resected with grossly negative margins. Point-based reregistration enabled instantaneous reregistration with minimal impact on RMS TRE compared with the initial registration (from 1.34 to 1.70 mm preresection and from 1.60 to 2.10 mm postresection). We present a novel and accurate registration and reregistration framework for use during IGS for PN with the da Vinci Xi surgical system. The technology is easily integrated into the surgical workflow and does not require additional hardware.
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http://dx.doi.org/10.1089/end.2020.0363DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7987368PMC
March 2021
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