Minimally Invasive Surgery Instruments Research Articles

One size does not fit all: Impact of hand size on ease of use of instruments for minimally invasive surgery

BackgroundConsideration of ergonomic factors is important for the practice of safe and efficient minimally invasive surgery (MIS). Surgeons with smaller glove sizes have previously been reported to have increased difficulties with some minimally invasive instruments. We aim to investigate hand anthropometrics and their relationship to surgeon comfort when using MIS instruments. MethodsMale and female surgeons from two centres were surveyed on their experience of handling MIS instruments and images obtained of the dorsal and palmar aspects of their dominant hand. Photographs of hands were transformed to calibrated coordinates to enable anthropometric measurements of finger length and width as well as palm width and hand span photogrammetrically. Surgeon-perceived discomfort, fatigue, pressure points and techniques to mitigate difficulty handling instruments were compared to hand measurements. ResultsQuestionnaires were completed by 58 surgeons; 20 (34%) were consultants, 17 (29%) were women. Glove size ranged from 6 to 8 (median 7.5). Male participants had significantly larger hands than females in all measured dimensions. Female surgeons and those with smaller finger and hand dimensions were significantly more likely to experience difficulty or discomfort across a range of variables when using MIS instruments. ConclusionsSurgeons with smaller hands reported increased problems handling MIS instruments. This represents an issue of equity in surgery, with women being more significantly affected than men. Hand size varies greatly between surgeons and anthropometric variability should be considered in design of MIS instruments.

Design Optimization of Asymmetric Patterns for Variable Stiffness of Continuum Tubular Robots

Variable stiffness mechanisms have become popular for improving the performance of meso/microscale robots due to their ability to enable safe, effective, and versatile operation without additional actuators. In minimally invasive surgery (MIS), they can provide low stiffness for adaptability and an extended workspace and high stiffness for stable manipulation. This study aims to optimize the pattern design that maximizes the stiffness ratio while preventing buckling. Longitudinal slits are identified as the ideal shape for maximizing the ratio using topology optimization. The effects of the design parameters are investigated by analytical modeling and finite-element analysis (FEA). Finally, we established a design optimization process to maximize the variable stiffness ratio while ensuring safety. The load and buckling tests of 19 cases are verified in both the experiment and FEA. Buckling occurred in eight cases, consistent with the expected results from the proposed map. Among the tested cases, the tube with the optimal pattern parameter set exhibits the highest stiffness ratio of 2.67 while satisfying the given stiffness constraint (greater than 0.3 times the flexural stiffness of the initial tube) and avoiding buckling. The proposed optimization method potentially enables an extended workspace and more versatile functionality for MIS instruments.

Steerable Surgical Instrument for Conventional and Single-Site Minimally Invasive Surgery.

Background. This article aims to present an innovative design of a steerable surgical instrument for conventional and single-site minimally invasive surgery (MIS), which improves the dexterity and maneuverability of the surgeon while offering a solution to the limitations of current tools. Methods. The steerable MIS instrument consists of a deflection structure with a curved sliding joints design that articulates the distal tip in two additional degrees of freedom (DoFs), relative to the instrument shaft, using transmission by cables. A passive ball-joint mechanism articulates the handle relative to the instrument shaft, improves wrist posture, and prevents collision of instrument handles during single-site MIS procedures. The two additional DoFs of the articulating tip are activated by a thumb-controlled device, using a joystick design mounted on the handle. This steerable MIS instrument was developed by additive manufacturing in a 3D printer using PLA polymer. Results. Prototype testing showed a maximum tip deflection of 60° in the left and right directions, with a total deflection of 120°. With the passive ball-joint fully offset, the steerable tip achieved a deflection of 90° for the right and 40° for the left direction, with a total deflection of 130°. Furthermore, the passive ball-joint mechanism in the handle obtained a maximum range of motion of 60°. Conclusions. This steerable MIS instrument concept offers an alternative to enhance the application fields of conventional and single-site MIS, increasing manual dexterity of the surgeon and the ability to reach narrow anatomies from other directions.

PATENTS OF MEDICAL-SURGICAL DEVICES IN SPAIN: WHAT, WHERE AND WHO INVENT AND PROTECT THEIR INVENTIONS?

Abstract INTRODUCTION Among the strategic lines of the EECTI document (Spanish Strategy for Science, Technology and Innovation 2021-2027) related with health, there is a subline that refers to: New diagnostic and therapeutic techniques. The objective is to analyze the patents of medical-surgical devices in the field of Minimally Invasive Surgery (MIS) in Spain. MATERIAL AND METHODS Data related to surgical devices in MIS and Laparoscopic Surgery are collected between January 2019 and December 2020 using the information from the Boletín de Vigilancia Tecnológica, documents obtained from collaboration between the OEPM and ITEMAS. They are extracted and analyzed in the patent application documents: the owner, the number of inventors by sex, Autonomous Community, type of device and health specialties where they are involved. RESULTS In the last two years, 16 patents of medical-surgical devices related to MIS have been published. In 7 cases (43.75%) the owner is an individual, in 6 cases a company (37.5%) and in 3 cases an institution (18.75%). 34 inventors are collected and only 6 (17.65%) of them are women. Most of them are for laparoscopic surgery devices related to specialties such as General and Digestive Surgery, Gynecology or Urology, and MIS instruments are mostly related to Traumatology and Orthopedic Surgery. CONCLUSIONS In recent years there are still few patents in Spain related to minimally invasive surgery. Most of the patents have private ownership, almost all with male inventors, from regions of the southeast of Spain and involving specialties that work in large cavities.

A Hybrid Electromagnetic and Tendon-Driven Actuator for Minimally Invasive Surgery

Minimally invasive surgery (MIS) is a surgical technique that facilitates access to the internal tissues and organs of a patient’s body via a limited number of small incisions or natural orifice of the patients. Such a technique requires specialized slender surgical instruments with a high levels of dexterity and functionality. However, the currently available MIS instruments are rigid and could offer only limited degrees of freedom (DOFs) that hampers the surgeon’s effort to perform the required operation accurately. In this study, we have developed a hybrid electromagnetic and tendon-driven actuator as an integral part of MIS surgical instruments to provide them with optimum angulation. The design uses a novel electromagnetic structure to lock the position of individual joints, and a tendon-driven structure for the articulation of the surgical instrument. The finite element method (FEM) was utilized to predict the performance of the actuator, which was experimentally validated. Subsequently, a prototype was assembled, and corresponding kinematics analysis was presented to visualize the improvement of the developed mechanism on the functional workspace of the MIS instruments. It was concluded that the developed mechanism could offer three additional DOFs for the surgical instrument and angulation of 180° for each articulated joint.

A lobster-inspired articulated shaft for minimally invasive surgery

Novel applications of soft pneumatic actuation in minimally invasive surgery (MIS) are proposed due to its relatively safe robot–environment interactions. Although the inherent compliance of soft robots makes them suitable for surgery, their low force output and complicated system response and behavior may limit their potential as practical MIS instruments. In this paper, three lobster-inspired antagonistic modules are proposed to realize bidirectional translational, bending and rotational motions and variable stiffness in centimeter scale. Their modular design enables flexible combinations of articulated shafts to satisfy end-effector workspace requirements in MIS. Theoretical models are proposed to relate the input pressure, deformation, output force/torque and stiffness, which provide quantitative solutions for independent adjustment on the deformation and stiffness of each module. A series of experimental results show that the proposed modules can deliver sufficient force and torque output for MIS applications, and they can be conveniently assembled into articulated shafts featuring safe actuation, high dexterity, stiffness tuning and reconfigurability.

Novel Miniature Tip Design for Enhancing Dexterity in Minimally Invasive Surgery

Even though technological advances have increased the application area of minimally invasive surgery (MIS), there are still hurdles to allow for widespread adoption for more complex procedures. The development of steerable instruments, in which the surgeon can alter the tip orientation, has increased the application area of MIS, but they are bulky, which limits their ability to navigate through narrow environments, and complex, which complicates miniaturization. Furthermore, they do not allow for navigating through complex anatomies. In an effort to improve the dexterity of the MIS instruments, while minimizing the outer dimensions, the previously developed cable-ring mechanism was redesigned, resulting in the thinnest, Ø 2 mm (Ø 1 mm lumen), eight degrees-of-freedom (DOF) multisteerable tip for MIS to date. The multisteerable tip consists of four steerable segments of 2DOF stackable elements allowing for ±90 deg articulation, as well the construction of complex shapes, actuated by 16 Ø 0.2 mm stainless steel cables. In a proof-of-principle experiment, an ultrasound transducer and optical shape sensing (OSS) fiber were inserted in the lumen, and the multisteerable tip was used to perform scanning motions in order to reconstruct a wire frame in three-dimensional (3D). This configuration could in future be used to safely navigate through delicate environments and allow for tissue characterization. Therefore, the multisteerable tip has the potential to increase the application area of MIS in future, as it allows for improved dexterity, the ability to guide several tip tools toward the operation area, and the ability to navigate through tight anatomies.

Design for Additive Manufacture of Fine Medical Instrumentation—DragonFlex Case Study

The recently popularized domain of additive manufacturing (AM) has much to offer to medical device development, especially to the growing field of minimally invasive surgery (MIS). With the advancements in AM materials, one could soon envision materializing not only the proofs of concept but also the final clinically approved instruments. DragonFlex—the world's first AM steerable MIS instrument prototype—was recently devised with the aim to follow this vision. Apart from the medical device design restrictions, several limitations of AM materials and processes had to be considered. The aim of this paper is to present these insights to those opting for this means of manufacture, serving as a helpful design and material guide. Over the course of its development, DragonFlex has gone through four design generations so far, each differing in the AM material and process used. Due to being a prototype of a MIS instrument of miniature dimensions, the printing processes were limited to stereolithography (SLA), as to achieve the best possible precision and accuracy. Each SLA process and material brought along specific advantages and disadvantages affecting the final printout quality, which needed to be compensated for either at the design stage, during, or after printing itself. The four DragonFlex generations were printed using the following SLA techniques and materials in this order: polymer jetting from Objet VeroBlue™; SLA Digital Light Processing™ (DLP) method from EnvisionTEC® NanoCure RCP30 and R5; conventional SLA from 3D Systems Accura® 60; and DLP based SLA process from a ceramic composite. The material choice and the printing orientation were found to influence the final printout accuracy and integrity of thin features, as well as material's postproduction behavior. The polymeric VeroBlue™ proved structurally sound, although suffering from undermined accuracy and requiring postprocessing, hence recommended for prototyping of upscaled designs of looser manufacturing tolerances or overdimensioned experimental setups. The NanoCure materials are capable of reaching the best accuracy requiring almost no postprocessing, thus ideal for prototyping small intricate features. Yet their mechanical functionality is undermined due to the high brittleness of RCP30 and high flexibility of R5. The transparent Accura® 60 was found to lose its strength and appeal due to high photosensitivity. Finally, the ceramic composite shows the best potential for medical use due to its biocompatibility and superior mechanical properties, yet one has to compensate for the material shrinkage already at the design stage.

Design and performance evaluation of a 3-axis force sensor for MIS palpation

Purpose – This paper aims to develop a novel miniature 3-axis force sensor which can detect the interaction forces during tissue palpation in MIS (minimally invasive surgery). MIS offers many significant merits compared with traditional open surgery, the wound to the patients and the postoperative pains are alleviated and reduced dramatically. However, the inherent drawback due to lack of force feedback still exists while conducting some operation procedures. For example, tissue palpation performed easily during open surgery could not be realized in an MIS manner. Design/methodology/approach – The force sensor is based on the resistive-based sensing method that utilizes strain gauges to measure the strain when the external loads are acting on the tip of the sensor. A novel flexible tripod structure with bending and compression deformations is designed to discriminate the magnitudes and directions of the three orthogonal force components. A linear characteristic matrix is derived to disclose the relationship between the sensitivity and the geometric parameters of the structure, and a straightforward geometric parameterized optimization method considering the sensitivity isotropy is proposed to provide the sensor structure with high sensitivity and adequate stiffness. Findings – The sensor prototype can perform force measurement with sensing ranges of ± 3.0 N in axial direction and ± 1.5 N in radial direction, and the resolutions are 5 per cent and 1 per cent, respectively. It is concluded that this force sensor is compatible with MIS instruments and the ex-vivo experiment shows that the sensor can be used to perform tissue palpation during MIS procedures. Originality/value – This paper is intended to address the significant role of force sensing and force feedback during MIS operations, and presents a new application of the resistive-based sensing method in MIS. A tripod structure is designed and a straightforward optimization method considering the sensitivity isotropy of the sensor is proposed to determine geometric parameters suited for the given external loads.

Attaining high bending stiffness by full actuation in steerable minimally invasive surgical instruments

Introduction: Steerable instruments are a promising trend in minimally invasive surgery (MIS), due to their manoeuvring capabilities enabling reaching over obstacles. Despite the great number of steerable joint designs, currently available steerable tips tend to be vulnerable to external loading, thus featuring low bending stiffness. This work aims to provide empirical evidence that the bending stiffness can be considerably increased by using fully actuated joint constructions, enabling left/right and up/down tip rotations with the minimum of two degrees of freedom (DOF), rather than conventional underactuated constructions enabling these rotations with more than two DOF. Material and methods: A steerable MIS instrument prototype with a fully actuated joint construction was compared to state-of-the-art underactuated steerable instruments in a number of tip deflection experiments. The tip deflections due to loading were measured by means of a universal testing machine in four bending scenarios: straight and bent over 20°, 40° and 60°. Results and conclusions: The experimental results support the claim that a fully actuated joint construction exhibits a significantly larger bending stiffness than an underactuated joint construction. Furthermore, it was shown that the underactuated instrument tips show a considerable difference between their neutral positions before and after loading, which could also be greatly minimised by full actuation.

Management of intended durotomy in minimally invasive intradural spine surgery: clinical article.

Minimally invasive surgery (MIS) has been increasingly used for the treatment of various intradural spinal pathologies in recent years. Although MIS techniques allow for successful treatment of intradural pathology, primary dural closure in MIS can be technically challenging due to a limited surgical corridor through the tubular retractor system. The authors describe their experience with 23 consecutive patients from a single institution who underwent MIS for intradural pathologies, along with a review of pertinent literature. A retrospective review of a prospectively collected surgical database was performed to identify patients who underwent MIS for intradural spinal pathologies between November 2006 and July 2013. Patient demographics, preoperative records, operative notes, and postoperative records were reviewed. Primary outcomes include operative duration, estimated blood loss, length of bed rest, length of hospital stay, and postoperative complications, which were recorded prospectively. Twenty-three patients who had undergone MIS for intradural spinal pathologies during the study period were identified. Fifteen patients (65.2%) were female and 8 (34.8%) were male. The mean age at surgery was 54.4 years (range 30-74 years). Surgical pathologies included neoplastic (17 patients), congenital (3 patients), vascular (2 patients), and degenerative (1 patient). The most common spinal region treated was lumbar (11 patients), followed by thoracic (9 patients), cervical (2 patients), and sacral (1 patient). The mean operative time was 161.1 minutes, and the mean estimated blood loss was 107.2 ml. All patients were allowed full activity less than 24 hours after surgery. The median length of stay was 78.2 hours. Primary sutured dural closure was achieved using specialized MIS instruments with adjuvant fibrin sealant in all cases. The rate of postoperative headache, nausea, vomiting, and diplopia was 0%. No case of cutaneous CSF fistula or symptomatic pseudomeningocele was identified at follow-up, and no patient required revision surgery. Primary dural closure with early mobilization is an effective strategy with excellent clinical outcomes in the use of MIS techniques for intradural spinal pathology. Prolonged bed rest after successful primary dural closure appears unnecessary, and the need for watertight dural closure should not prevent the use of MIS techniques in this specific patient population.

Preliminary Articulable Probe Designs With RAVEN and Challenges: Image-Guided Robotic Surgery Multitool System

The primary focus of the vision systems in current minimally invasive surgery (MIS) surgical systems has been on the improvement of immersive experience through a static approach. One of the current limitations in an MIS robotic surgery is the limited field of view and restricted perspective due to the use of a sole rigid 3D endoscope. We seek to integrate a modular articulable imaging device and the teleoperated surgical robot, RAVEN. Another additional flexible imager can be helpful in viewing occluded surgical targets, giving increased visualization options. Two probe designs are proposed and tested to evaluate a robotized steering mechanism within the MIS robot framework. Both designs, a separate flexible imager and a fixed camera on a tool tip, did not show much improvement in reducing task completion time. The new system may have some potential in improved precise manipulation of surgical tools, which may offer safety benefits once the surgeon is trained. We have demonstrated feasibility of a novel MIS instrument imaging device to aid in viewing potentially occluded surgical targets. A new concept, a modular axis-shared articulable imaging probe located at the vicinity of a tool tip, is proposed for future evaluation. Full integration of the new flexible imaging device into the grasper of the RAVEN surgical robot is under study coordinated with clinicians.

Uniaxial Wireless Tissue Palpation Device for Minimally Invasive Surgery

Nowadays surgery tends to be performed with minimally invasive techniques that result in less post-operative pain, recovery time and smaller incisions. However, unlike open surgery, during minimally invasive surgery (MIS) the surgeon has few chances to rely on tactile and kinesthetic feedback [1]. Tissue palpation aids in preventing traumas or in leveraging tactile information to identify tumors, vessels and organic structures buried underneath the tissue surface. Therefore, in the last two decades, research on palpation devices strived to restore tactile and kinesthetic sensations in MIS. This was pursued by performing tissue palpation with different techniques, such as indenting [2], grasping [3] or rolling [1]. Despite this research effort, a translation into clinical practice is still far to come. Even further, surgeons are resistant to the option of devoting a surgical port to a palpation device, because of the available ports are needed for the MIS instruments. As an alternative to this approach, intraoperative ultrasonography devices (IOUS) may be used to detect buried structures [4]. Also this technology, however, requires a dedicated surgical port during the entire procedure.

F112004 流体を用いた手術機器

This paper presents the usefulness and possibility of fluid for instruments for minimally invasive surgery (MIS). MIS such as laparoscopic surgery and thoracoscopic surgery continues to gain popularity and manipulation of internal organs in a minimally invasive manner is highly required. For such requirements, development of new MIS instruments other than a multi-degree-of-freedom forceps is necessary. Fluid can go in and out of a human body through a small incision or natural orifices. Its usefulness could create new inventions in the development of MIS instruments. Fluid is also advantageous over electricity in cost, sterilization and elimination of the risk of an electric shock. This paper introduces surgical instruments using fluid we have recently developed to discuss its usefulness and possibility. Those are an assemblable hand driven by water pressure, a sound based force sensor, a lung suction positioner, and an air-driven multi-tube propulsion for a large intestine endoscope.

Hyperelastic modelling and parametric study of soft tissue embedded lump for MIS applications

The existing MIS (minimally invasive surgery) instruments have caused severe restrictions to surgeons' tactile perception. In particular, palpation, which is an important technique in open surgery to assess the softness of the tissue and to detect any hidden lumps, is entirely absent in MIS procedures. Many researchers have developed smart endoscopic graspers to rectify different aspects of this problem. However, the effect of an anatomical feature in general and a lump in particular on the stress distribution on the sensitive surfaces of the smart MIS graspers still needs a lot of attention. This paper investigates the effect of the important parameters of a lump on the stress distribution at the contact surface and subsequently the output of smart endoscopic graspers. Using experimental stress-strain compression test data, the material parameters required for the Mooney-Rivlin model were obtained and used in hyperelastic finite element analysis. The influence of size, depth and stiffness of the lump on the stress distribution at the contact surface are shown and discussed. The results of the non-linear finite element analysis were validated against experiments conducted on elastomeric material replicating soft tissue. The consistency between finite element analysis results and experimental work validates the developed model, which is based on the hyperelastic formulation. The finite element analysis results obtained in this study are particularly useful for the development of an inverse model. The inverse model would extract fundamental information, such as size, depth and stiffness, of any hidden lump, using the outputs of the sensors.

Robotically assisted esophago-esophagostomy in newborn pigs

Purpose Repair of esophageal atresia and tracheoesophageal fistula (TEF) in the newborn is challenging when done as an open procedure but only a few surgeons have attempted this with minimally invasive surgery (MIS). Surgical robots that hold MIS instruments have wrists and provide tremor filtration and motion scaling, which might be expected to facilitate complex procedures in small spaces such as an esophageal anastomosis in a newborn. Methods Seven newborn pigs weighing 2 to 3 kg were used as a model. The authors performed an esophageal resection and end-to-end anastomosis using the Zeus Microwrist Robotic Surgical System. The authors monitored the following data-Zeus robotic set-up time, operating time, esophageal dissection time, and anastomosis time. After 1 month, the animals were anesthetized to perform esophagram and than were killed. Results In these very small animals the space available for performing an anastomosis is very limited, approximately 2 cm 3. Two pigs each died 18 days postoperatively. One animal could not eat and died during esophageal dilation. The second pig died of unrelated enteritis. Neither had evidence of anastomotic leak at autopsy. The esophagram of the 5 pigs that survived for 30 days showed no narrowing or proximal dilation in 2. In 3 there was some stenosis requiring dilation. Histopathology was done on each operated animal. Two of the anastomoses were well healed, and 5 showed only focal small ulceration. Conclusions Robotic assistance facilitates an MIS approach to the upper esophagus even in the limited space of the infant chest.

Principles of ergonomic instrument handles

Minimally invasive surgery (MIS) has become firmly established during the last decade. The advantages for patients are well recognised. Surgeons, however, must cope with disadvantages caused by an unergonomic working place. This includes architecture, operating room (OR) design, team interaction, equipment and, finally, posture and instrument handles. To prevent pressure areas, persisting nerve lesions, muscle cramps and fatigue caused by unergonomic tools it is necessary for the surgeon, both as a purchaser and user of laparoscopic instruments, to know the principles of ergonomically designed handles for MIS instruments. Anatomical, physiological and ergonomic facts are presented. An ideal ergonomic working posture for the laparoscopic surgeon and an optimal grasp for manipulating the instrument's functional elements are recommended. Criteria for genuine 'ergonomic handles' are established. These criteria enable the surgeon to evaluate ergonomic handles for MIS instruments according to his/her particular needs.

Instruments for minimally invasive surgery

Although the advantages of minimally invasive surgery (MIS) have been clearly established for the patient, the surgeon must cope with disadvantages caused by unergonomic instrument handles. Pressure areas and persisting nerve lesions have been described in the literature. The shape of the instrument handles has been identified as the reason for these disorders. To prevent these, it is necessary to use ergonomically designed handles for MIS instruments. Anatomic, physiologic, and ergonomic facts as well as the results of the authors' own experiences and tests are presented. On this basis, an ideal ergonomic working posture for the laparoscopic surgeon and an optimal grasp for manipulating the instruments' functional elements are recommended. To enable the surgeon to evaluate ergonomic handles for MIS instruments according to his own needs, 14 criteria for genuine "ergonomic handles" are established. On the basis of these criteria, deficiencies of handles currently available (ring and shank handles at an angle or with axial extension to the instrument shaft, and pistol handles) are discussed. Furthermore, new handles, developed by the authors according to the criteria for genuine ergonomic handles, are presented.