Vance Watson

Interventional robotic systems: Applications and technology state‐of‐the‐art

Many different robotic systems have been developed for invasive medical procedures. In this article we will focus on robotic systems for image‐guided interventions such as biopsy of suspicious lesions, interstitial tumor treatment, or needle placement for spinal blocks and neurolysis. Medical robotics is a young and evolving field and the ultimate role of these systems has yet to be determined. This paper presents four interventional robotics systems designed to work with MRI, CT, fluoroscopy, and ultrasound imaging devices. The details of each system are given along with any phantom, animal, or human trials. The systems include the AcuBot for active needle insertion under CT or fluoroscopy, the B‐Rob systems for needle placement using CT or ultrasound, the INNOMOTION for MRI and CT interventions, and the MRBot for MRI procedures. Following these descriptions, the technology issues of image compatibility, registration, patient movement and respiration, force feedback, and control mode are briefly discussed. It is our belief that robotic systems will be an important part of future interventions, but more research and clinical trials are needed. The possibility of performing new clinical procedures that the human cannot achieve remains an ultimate goal for medical robotics. Engineers and physicians should work together to create and validate these systems for the benefits of patients everywhere.

AcuBot: a robot for radiological interventions

We report the development of a robot for radiological percutaneous interventions using uniplanar fluoroscopy, biplanar fluoroscopy, or computed tomography (CT) for needle biopsy, radio frequency ablation, cryotherapy, and other needle procedures. AcuBot is a compact six-degree-of-freedom robot for manipulating a needle or other slender surgical instrument in the confined space of the imager without inducing image artifacts. Its distinctive characteristic is its decoupled motion capability correlated to the positioning, orientation, and instrument insertion steps of the percutaneous intervention. This approach allows each step of the intervention to be performed using a separate mechanism of the robot. One major advantage of this kinematic approach is patient safety. The first feasibility experiment performed with the robot, a cadaver study of perispinal blocks under biplanar fluoroscopy, is presented. The main expected application of this system is to CT-based procedures. AcuBot has received Food and Drug Administration clearance (IDE G010331/S1), and a clinical trial of using the robot for perispinal nerve and facet blocks is presently underway at Georgetown University, Washington, DC.

Needle-Based Interventions With the Image-Guided Surgery Toolkit (IGSTK): From Phantoms to Clinical Trials

We present three image-guided navigation systems developed for needle-based interventional radiology procedures, using the open source image-guided surgery toolkit (IGSTK). The clinical procedures we address are vertebroplasty, RF ablation of large lung tumors, and lung biopsy. In vertebroplasty, our system replaces the use of fluoroscopy, reducing radiation exposure to patient and physician. We evaluate this system using a custom phantom and compare the results obtained by a medical student, an interventional radiology fellow, and an attending physician. In RF ablation of large lung tumors, our system provides an automated interventional plan that minimizes damage to healthy tissue and avoids critical structures, in addition to accurate guidance of multiple electrode insertions. We evaluate the systems performance using an animal model. Finally, in the lung biopsy procedure, our system replaces the use of computed tomographic (CT) fluoroscopy, reducing radiation exposure to patient and physician, while at the same time enabling oblique trajectories which are considered challenging under CT fluoroscopy. This system is currently being used in an ongoing clinical trial at Georgetown University Hospital and was used in three cases.

Technology improvements for image-guided and minimally invasive spine procedures

This paper reports on technology developments aimed at improving the state of the art for image-guided minimally invasive spine procedures. Back pain is a major health problem with serious economic consequences. Minimally invasive procedures to treat back pain are rapidly growing in popularity due to improvements in technique and the substantially reduced trauma to the patient versus open spinal surgery. Image guidance is an enabling technology for minimally invasive procedures, but technical problems remain that may limit the wider applicability of these techniques. The paper begins with a discussion of low back pain and the potential shortcomings of open back surgery. The advantages of minimally invasive procedures are enumerated, followed by a list of technical problems that must be overcome to enable the more widespread dissemination of these techniques. The technical problems include improved intraoperative imaging, fusion of images from multiple modalities, the visualization of oblique paths, percutaneous spine tracking, mechanical instrument guidance, and software architectures for technology integration. Technical developments to address some of these problems are discussed next. The discussion includes intraoperative computerized tomography (CT) imaging, magnetic resonance imaging (MRI)/CT image registration, three-dimensional (3-D) visualization, optical localization, and robotics for percutaneous instrument placement. Finally, the paper concludes by presenting several representative clinical applications: biopsy, vertebroplasty, nerve and facet blocks, and shunt placement. The program presented here is a first step to developing the physician-assist systems of the future, which will incorporate visualization, tracking, and robotics to enable the precision placement and manipulation of instruments with minimal trauma to the patient.

Robotically assisted nerve and facet blocks: a cadaveric study.

RATIONALE AND OBJECTIVES This study was performed to evaluate the feasibility of using a joystick-controlled robotic needle driver to place a 22-gauge needle for nerve and facet blocks. MATERIALS AND METHODS Biplane fluoroscopy and a robotic needle driver were used to place 12 needles into the lumbar paraspinal region of an embalmed female cadaver (age at death, 98 years). Small metal BB nipple markers (1 mm in diameter) were inserted percutaneously to serve as targets. Six needles were then placed near the nerve root, and six were placed near the facet root. Anteroposterior and lateral radiographs were obtained after each needle placement to assess its accuracy. RESULTS All needles were placed within 3 mm of the target BB. The average distance was 1.44 mm +/- 0.66 (standard deviation). DISCUSSION A robotic needle driver can be used to place needles accurately in the nerve and facet regions. Clinical studies are required to investigate the advantages and disadvantages of this system for interventional procedures involving needles.

Robotically Assisted Interventions: Clinical Trial for Spinal Blocks

Percutaneous interventions are performed by freehand passages of instruments, such as needles, from the skin surface to the anatomy of interest. The main problem with this approach is that the physician can be inaccurate in aligning the instrument and staying on course. A joystick-controlled robotic needle driver may allow the physician to more precisely target the anatomy. This paper describes our experience with a robotic needle driver in a 20-patient clinical trial of nerve and facet blocks. Our next stage of research in robotically assisted lung biopsy is also mentioned.

CT-directed robotic biopsy testbed: motivation and concept

As a demonstration platform, we are developing a robotic biopsy testbed incorporating a mobile CT scanner, a small needle driver robot, and an optical localizer. This testbed will be used to compare robotically assisted biopsy to the current manual technique, and allow us to investigate software architectures for integrating multiple medical devices. This is a collaboration between engineers and physicians from three universities and a commercial vendor. In this paper we describe the CT-directed biopsy technique, review some other biopsy systems including passive and semi- autonomous devices, describe our testbed components, and present our software architecture. This testbed is a first step in developing the image-guided, robotically assisted, physician directed, biopsy systems of the future.

Accuracy Analysis of an Image-Guided System for Vertebroplasty Spinal Therapy based on Electromagnetic Tracking of Instruments

Vertebroplasty is a minimally invasive procedure in which bone cement is pumped into a fractured vertebral body that has been weakened by osteoporosis, long-term steroid use, or cancer. In this therapy, a trocar (large bore hollow needle) is inserted through the pedicle of the vertebral body which is a narrow passage and requires great skill on the part of the physician to avoid going outside of the pathway. In clinical practice, this procedure is typically done using 2D X-ray fluoroscopy. To investigate the feasibility of providing 3D image guidance, we developed an image-guided system based on electromagnetic tracking and our open source software platform the Image-Guided Surgery Toolkit (IGSTK). The system includes path planning, interactive 3D navigation, and dynamic referencing. This paper will describe the system and our initial evaluation.

I-SPINE: A software package for advances in image-guided and minimally invasive spine procedures

While image guidance is now routinely used in the brain in the form of frameless stereotaxy, it is beginning to be more widely used in other clinical areas such as the spine. At Georgetown University Medical Center, we are developing a program to provide advanced visualization and image guidance for minimally invasive spine procedures. This is a collaboration between an engineering-based research group and physicians from the radiology, neurosurgery, and orthopaedics departments. A major component of this work is the ISIS Center Spine Procedures Imaging and Navigation Engine, which is a software package under development as the base platform for technical advances.

Medical Robotics workshop--MRWS.

Medical Robotics Workshop MRWS Kevin Cleary a; Brian Davies b; Gabor Fichtinger c; Jocelyne Troccaz d; Tim Lueth e; Vance Watson f a ISIS Center, Department of Radiology, Georgetown University Medical Center, Washington, DC, USA b Department of Mechanical Engineering, Imperial College, London, UK c Center for Computer-Integrated Surgery, Johns Hopkins University, Baltimore, Maryland, USA d Laboratoire TIMC, Faculte de Medecine, Universite Joseph Fourier, Grenoble, France e Surgical Navigation and Robotics Lab, Charite Campus Virchow, Berlin, Germany f Department of Radiology, Georgetown University Hospital/MedStar Health, Washington, DC, USA