A Hand-Held Non-Robotic Surgical Tool With a Wrist and an Elbow.

OBJECTIVE: This paper describes a surgical device that provides both wrist and elbow dexterity without motors or electronics. The device provides dexterity advantages in minimally invasive surgery typically associated with robotic systems, but does so with many fewer components. Fully mechanical designs of this type promise to deliver "robot-like dexterity" at a lower financial cost than current surgical robotic systems. METHODS: Most non-robotic articulated surgical tools developed to date feature one or two degrees-of-freedom (DOF) close to the tool tip (i.e., a "wrist"). In this paper, we describe a new tool that not only features a two-DOF wrist, but also augments its dexterity with a two-DOF "elbow" consisting of a multi-backbone design seen previously only in robotic systems. Such an elbow offers high stiffness in a thin form factor. This elbow requires static balancing, which we accomplish with springs in the handle, so that the surgeon can benefit from the stiffness without feeling it while using the device. RESULTS: We report the overall tool design and experiments evaluating how well our static balance mechanism compensates for the multi-backbone elbow's intrinsic stiffness. CONCLUSION: We demonstrate the use of a multi-backbone elbow in a manual tool for the first time and show how to combine the elbow with a pin joint wrist in a fully mechanical (i.e., non-robotic) tool. SIGNIFICANCE: This paper is a step toward high dexterity, low-cost surgical instruments that bring some benefits of surgical robotic systems to patients and surgeons at a lower cost.

Robot-like dexterity without computers and motors: a review of hand-held laparoscopic instruments with wrist-like tip articulation.

INTRODUCTION: Conventional manual laparoscopic instruments for minimally invasive surgery have limited dexterity within the patient, making procedures challenging. Surgical robotic systems offer enhanced articulation, but at substantial financial costs. This has motivated the development of high-dexterity, low-cost laparoscopic instruments. AREAS COVERED: This article reviews both commercial and academic results on creating fully mechanical (i.e. non-robotic) laparoscopic instruments that provide wrists or wrist-like dexterity within the patient. We review the state of the art in the development of these mechanical instruments, focusing on the surgeon interface, wrist mechanism, and the kinematic mapping between the two. Expert commentary: Current articulated mechanical laparoscopic instruments exhibit a wide range of designs, with no clear consensus on what makes such devices easy to use. As these technologies mature, user studies are needed to determine surgeon preferences. Articulated, low-cost instruments have the potential to impact the minimally invasive surgery market if they provide compelling benefits to surgeons.

Comparing a Mechanical Analogue With the Da Vinci User Interface: Suturing at Challenging Angles.

The da Vinci Surgical System offers a natural user interface and wrist articulation, which enable suturing and other complex surgical actions in confined spaces. However, both the one-time cost of the system and the recurring cost of the limited-use instruments remain high. This has motivated the development of several hand-held alternatives-some partially motorized, some fully mechanical-in recent years. While a few of these have been commercialized, none have yet met with broad commercial success comparable to the da Vinci robot. In this letter, we suggest a user interface-based explanation for this, and describe a new mechanical instrument that provides wrist articulation with a novel user interface. We provide results of a single-user pilot study with an experienced laparoscopic surgeon to compare the new device with a traditional wristless laparoscopic tool, a prior commercial wristed mechanical tool (the RealHand), and the da Vinci robot, in the context of suturing at challenging angles. We observe better targeting of desired suture needle entry and exit points with the new device in comparison to prior wristed and wristless mechanical instruments, with the da Vinci only slightly outperforming the new tool.

Mapping the articular contact area of the long head of the biceps tendon on the humeral head.

The purpose of this investigation was to calculate the contact surface area of the long head of the biceps (LHB) in neutral position and abduction. We sought to determine whether the LHB articulates with the humeral head in a consistent pattern comparing articular contact area in neutral position and abduction. Eleven fresh frozen matched cadaveric shoulders were analyzed. The path of the biceps tendon on the articular surface of the humeral head and the total articular surface were digitized using a MicronTracker 2 H3-60 three-dimensional optical tracker. Contact surface area was significantly less in abduction than in neutral position (P = 0.002) with a median ratio of 41% (36%, 47.5%). Ratios of contact area in neutral position to full articular surface area were consistent between left and right shoulders (rho = 1, P = 0.017) as were ratios of abduction area to full articular surface area (rho = 0.97, P = 0.005). The articular contact surface area is significantly greater in neutral position than abduction. The ratios of articular contact surface areas to total humeral articular surface areas have a narrow range and are consistent between left and right shoulders of the same cadaver.

Debulking from within: a robotic steerable cannula for intracerebral hemorrhage evacuation.

New approaches to intracerebral hemorrhage management are motivated by its high incidence and 40% mortality rate. Surgery is sometimes attempted to decompress the brain, although patient outcomes are similar regardless of whether surgery occurs. We hypothesize that surgical decompression is not more effective because current open surgical techniques disrupt healthy brain tissue to access the clot formed by the hemorrhage, offsetting the benefits of surgery. To address this, we propose a less invasive needle-based approach in which the clot is debulked from within using a superelastic, precurved aspiration cannula that is deployed from a needle. The tip of this aspiration cannula is controlled by coordinated insertion and retraction of the cannula and needle, as well as axial rotation of the cannula. We describe the design of a sterilizable and biocompatible robot that can control the three degrees of freedom of the needle and cannula. Image guidance is achieved by adapting an approach originally developed for brain biopsy. We provide an optimization method for the selection of the precurvatures of one or more sequentially used aspiration cannulas to maximize hemorrhage evacuation, based on preoperative medical image data. In vitro experiments demonstrate the feasibility of evacuating 83-92% of hemorrhage volume, depending on the number of tubes and deployment method used.

Minimally invasive holographic surface scanning for soft-tissue image registration.

Recent advances in registration have extended intrasurgical image guidance from its origins in bone-based procedures to new applications in soft tissues, thus enabling visualization of spatial relationships between surgical instruments and subsurface structures before incisions begin. Preoperative images are generally registered to soft tissues through aligning segmented volumetric image data with an intraoperatively sensed cloud of organ surface points. However, there is currently no viable noncontact minimally invasive scanning technology that can collect these points through a single laparoscopic port, which limits wider adoption of soft-tissue image guidance. In this paper, we describe a system based on conoscopic holography that is capable of minimally invasive surface scanning. We present the results of several validation experiments scanning ex vivo biological and phantom tissues with a system consisting of a tracked, off-the-shelf, relatively inexpensive conoscopic holography unit. These experiments indicate that conoscopic holography is suitable for use with biological tissues, and can provide surface scans of comparable quality to existing clinically used laser range scanning systems that require open surgery. We demonstrate experimentally that conoscopic holography can be used to guide a surgical needle to desired subsurface targets with an average tip error of less than 3 mm.