neurosurgery and robot technology

Neurosurgery has always been one of the most difficult and prominent fields of medical research. The implementation of innovations and improvements, as well as the adaptation of new approaches, processes, and computers, has been consistent enough. These functions are carried out positively in order to improve the effectiveness and safety of central and peripheral nervous system surgeries. Surgical and navigational robotics are examples of these capabilities. This paper discusses some of the most helpful and ideal frameworks in neurosurgery. Focusing on the navigational aspect, it provides information on different strategies that are being implemented in the field such as radiological, stereotaxic processes, and near-infrared. The objective of this research is to deliberate the most important frameworks for navigation in terms of neurological adaptations, their implications, and to argumentatively identify the improvements of robot navigation in neurosurgery, given exceptional anatomical structures of human body.

Keywords: Robotics, Neurosurgery, Robotic Navigation.

Introduction

The procedures involved in neurosurgery entail bone cutting or drilling. It means that there is significant danger exposed to the patient_x0092_s spinal cord, brain, and nerve roots. Surgical tools that can assist in improving the outcomes of the surgery are useful for achieving accuracies and shorter time in the surgical procedure as well as benefiting through lower costs. Robotic tracking as well as imaging technologies are useful in improving the outcomes of neurosurgical in the operating room [1]. This paper highlights the robotic navigation in neurosurgery and the overall procedures that are involved in the process; it addresses the manual and automation operation processes to indicate the value and perception of science in the field. The paper initiates with an explanation of the medical robotics development, followed by current navigation systems and applications in neurosurgery, and an evaluation of current limitations [2]. There is also a viable discussion present on the future of robotic navigation in neurosurgery.

Various illnesses can be treated through neurosurgery including spinal fractures, brain tumors as well as other conditions of neurology [3]. Neurosurgical treatment entails the last intervention towards providing healthcare solution to these illnesses.

Non-robotic surgery is also known as open surgery. The risks associated with this type of surgery are that it is more painful when compared to robotic surgery. The patient also loses a lot of blood unlike in robotic surgery. It means that the patient will require more blood transfusion and this may increase the costs. The patients may also experience less quality of life physically because of increased pain within the first few weeks. As for the benefits, the non-robotic surgery is known to be less expensive and similar good outcomes like robotic surgery in the long term [4]. Pain may be experienced by the patients when undergoing the operation and during the first one week after the surgery. The pain is three times when compared to that of robotic surgery. Besides the patient experiences low physical quality of life within the first six weeks after the operation.

Before the operation starts, the pre-operative image data is usually matched with the present position of the patient through an image registration process. The registration is usually paired based on point or the use of routines matched on the surface [5]. Image registration entails the process of changing images into the coordinate system during the navigational plan. Rigid and non-rigid methods are used in obtaining image registration. Example of rigid techniques are rotation and translation. No-rigid methods include local shifts within the brain and lesioned tissue. The later are more accurate than the rigid methods of image registration [6].

Patients are exposed to the risks of cutting and drilling of bones when accessing lesions and tumors. Here, accidental plunging of the surgical drill can occur to the brain and spinal cord. The patient can incur cranial nerves, blood vessels as well as brain tissues that are damaged. Brain exposure may also lead to infection that might cause the need for extra surgeries as well as further increases to healthcare costs. There are also risks of developing plunging complications of perforators and cranial drills [1]. Robotic surgery benefits the patient by providing advanced treatment of illnesses that are complicated. They provide healthcare using current technology that helps the patient to heal from illnesses that were earlier known to be terminal. The use of neurological tools assists in carrying out an operative procedure using technology [1]. This has improved the visualization system and minimal invasive trends in surgeries.

Preoperative Modalities

The pre-operative data serves the purpose of allowing the healthcare professionals to prepare for the neurosurgical procedure. They can understand the areas that need surgery, the time needed in the surgical procedure and the skills needed for applying in the procedure. In this case, the neurosurgeons can determine the best timing to carry out the surgery and what method they can use. The fundamental step for the use of neuro-navigational systems is the formation of 3D pre-operative image data combined with the patient_x0092_s anatomy by registration [7]. Once an accurate registration is achieved, it becomes the robotic applications to work in the mathematical space without a probability of errors.

The Imaging techniques include:

Computerized Tomography (CT)

Intraoperative Tracking Systems

Radiologic Navigation

Nuclear Magnetic Resonance Imaging (MRI)

This form of imaging technique is an emerging medical method used in radiology to cultivate pictures of the anatomical features along with the physiological processes of the body in both disease and health [8]. MRI scanners implement strong magnetic fields, field gradients, and radio waves to form images of the organs and tissues of the parenchymal origin. The technique is based on the understanding of nuclear magnetic resonance (NMR) and forms similar practical applications as computerized topography [8]. The opaque X-ray, N shaped device is substituted by an analogous system apparent on the MR images; these are most commonly used for the composition of tubes filled with a gadolinium solution.

In order to perform a diagnosis, the principle of MRI scanning begins with the placement of patient within the scanner that cultivates a supportive magnetic field surrounding the object that is to be recorded. Considering most of the applications in the field, hydrogen atoms as protons in the tissue comprise molecules of water from a commencement that is further analyzed to derive the body image. Initially, energy from a magnetic field that is oscillating is implemented to the patient temporarily on suitable replication intensity. The hydrogen atoms that are excited enough take out a signal of radio frequency, which is determined by perceiving coiling [8]. These signals of radio frequency can be made to outline information on the position by changing the important field of magnetism with the use of gradient coils. With the rapid movement of the coils, turning on an off consistently, they form the distinctive monotonous sound which is produced in an MRI scan. It is feasible to bring about a differentiation between multiple tissues; the process is outlined through the frequency on which atoms that were excited go back to their normal physiological, steadiness nature. Agents that are used for contrasting, being from exogenous origin may be provided orally, intra-articularly or intravenously.

Computerized Tomography (CT)

Computerized tomography, which is known to be the first tomographic imaging technique to be implemented, is one of the most common methods to localize and navigate neurosurgery applications. N-shaped applications, which are located to the frames of stereotaxic equipment, and the interrelations of the X-ray rods, can provide visible traces in the images. These can also determine the angle and dimension of inclination of the slice in association to the plane of the frame [9]. The position of a target point in a particular organ slice in association to the markers allows it_x0092_s coordinated in the stereotaxic localization to be attained. These calculations and measurements can be influenced on the films manually, but with the installation of specific software on the imaging machine or, more commonly, on associated computers, allows the traces of the N-shaped device left in the images to be evaluated automatically [9]. These also enable the coordinates of a target point selected by the user to be analyzed quickly.

Digital processing geometry is implemented to form a corresponding and dynamic 3D view of the inner sections of the object from a considerable portion of 2D radiographic images derived from a specific rotational axial arrangement. The images of cross sectional nature obtained are further utilized for neurosurgical navigation [10]. Initially, the process entirely eradicates the comprehension and possibility of superimposed descriptions of constructions out of the interest capacity. Moreover, due to the characteristic high-contrast CT resolution, differentiations in cellular structures that contrast in density of physical nature by less than 1% can be noted [11]. Finally, information from a single computerized tomography imaging process comprising either different contiguous or one image of helical nature can be viewed as pictures in the axial, coronal, or sagittal planes, relying on the diagnostic features of the functionalities.

Intraoperative Tracking Systems

Intraoperative tracing system in neurological operations acts as a guiding image technique. It is an image-guided method necessary during neurosurgery. It generates images used for guiding neurosurgery and represents an important step in improving surgical treatment of vascular malformations, tumors, as well as intracranial lesions [12].

Radiologic Navigation

Radiological navigations or image guided neurosurgical applications in the modern world are frequently implemented for operations of multiple brain tumors, for smaller and deeply sub cortically located lesions or cavernomas [13]. These techniques are suitable enough for determining the position of the target point in association with the landmarks demonstrating the frame position and represented in the imaging modality under consideration [9]. The coordinates provided with these functionalities can be used to plan out the trajectories of biopsy, to place suitable applications of tumor resection, to position the iso-centers in case of radiation therapy, or to implant deeper electrodes [9]. These methods can also form a basis for identifying target volumes.

After the invention of X-ray view boxes, evolutionary methods allowed the implementation of actual imaging methods for instance intraoperative ultrasound and fluoroscopy [14]. The involvement of computerized tomography (CT) in the 1970s and MRI (magnetic resonance imaging) in the 1990s resulted in different neuro-navigational applications for surgical working and planning. Frameless neuro-navigational support processes in comparison with frame-based devices record the movement of instruments and techniques in space through ultrasonic, electromagnetic, or optical sensors [14]. Their associative position from the lesion can be represented from preoperative imaging but not in an intraoperative practical measure. With a consistent development of navigational devices, neurosurgeons have been able to carry out the surgical procedures with an unprecedented degree of movement and accuracy; they can also carry out planning and a substantial variety of neurosurgical procedures [14]. With the development of this contextual agreement, the development of radiological navigation outlines a substantial improvisation in the microsurgical treatment of tumors, additional intracranial lesions, and vascular deformities.

Infrared Tracking (IR Tracking) Systems

These methods are occasionally used comprising a filter of optical band-pass eliminating all light ambiences of wavelengths that are additional. The process makes the documentation of optical indicators a considerably basic and dependable function [15]. There are two forms of IR trackers that are utilized for neurosurgical navigation. However, their clinical applications are diversified.

Optical Active Trackers

Different LEDs (sterilizable) that are operational in the near-IR series (having wavelength of about 900nm) are implemented as indicators, being identified by either three linear or two linear CCD units that outline the video modulation. The indicators as LEDs are sequentially derived and perceived with the help of this structure. There is a central unit present which derives a triangulation process based on the particular distance between the elements of CCD, known mathematic formation and emission order of every LED [15]. At minimum, LEDs of three non-collinear orientations are required for highlighting gradations of motion and movement (DOF). Since the LEDs must have a power generation system, conventionally active systems were also wired ones.

Optical Passive Trackers

Systems of such coordination perform in the near IR range. Besides markers of active origin, they have the capability to work with spheres (retroreflective) that are irradiated by the vision prospect in the range. The reflective markers design has to be individually distinctive for each tracing video so there was a definite implementation of each probe in an effectual manner; 2D images are used for such identifications as well. For this purpose, techniques as such and methods are always developed with CCD cameras that work in two dimensions [15]. One of the major benefits of these systems is that no electrical arrangements are required for the tracked probes and the tracking system.

Tracking Systems of Lasers

Instead of using a set of LEDs for localization, a systematic framework of photo-sensors can be placed on a stiff importer. Implementing a couple of fans comprising focused laser light released by conventional lasers of semiconductor origin are projected with the mirror rotations. This mechanism provides a laser beam that is fan shaped, sweeping off the counter capacity [15]. The stronger mechanical position is measured by consistently selecting the sweep fan positioning and the transcended signals from the photo-sensors.

These IR tracking systems along with optical tracking technologies are incorporated into the neurosurgery navigational applications due to their high reliability and accuracy levels. Within the clinical environment, the usability of such procedures has provided maximum potential. On a few conditions and instances, there have been times in surgical applications where the application of high intensity infrared rays from the passive IR trackers LEDs hinders additional infrared devices in the functional area, but severe negative outcomes have been rarely recorded. Besides their limitation of line-of-sight, these procedures are innovative and beneficial enough for standardized clinical applications.

Stereotaxic Fixation

Working Principle

Stereotaxic navigation works on different frame systems that are based on essential principles and regularities. It functions with the help of three main constituents:

A stereotaxic planning system, involving atlas, coordinates calculator, multimodality image correspondence tools, etc.

A stereotaxic apparatus or device

A stereotaxic placement and localization process

Modern and the most updated version of robotic navigation involve efficient planning systems as they are digitally modified and placed. The defined atlas is a group of different sections and divisions of organ structures and anatomies (for instance, brain of human), represented in association to a dual frame coordinate. Therefore, individual ideology in the brain can be feasibly provide an extensive series of three synchronized codes, which will be implemented for the stereotaxic equipment placement. In most cases, the three dimensions are: dorso-ventral (y), latero-lateral (x), and rostro-caudal (z). The stereotaxic equipment uses a group of thee synchronized codes (x, y and z) in a reference frame that is orthogonal in nature, or otherwise, a suitable coordinate arrangement, having three coordinates: depth, angle, and antero-posterior location [16]. The navigation device controls clamps that hold the head in position and bars which provide a fixed position for head in positioning to origination and coordination mechanisms.

The accuracy of stereotaxic navigation is dependent on different factors affecting the intraoperative accuracy of stereotaxic systems. Target localization greatly depends on the localizer technology present in 3D space. The software and computer applications maintain the correspondence and response generation between the localizer information and the images. Accuracy is also ensured with the target stability and the capability of the localizer to attempt on the target in physical space [17]. The ISG wand for viewing or similar supported functions has been outlined to provide an accurateness of about 2.5mm. Having an infrared pointer system that is LED-based, the localization process for the targets has increased even more; the outcomes have been recorded to be between 2 and 4mm.

Stereotaxic navigation with framed or frameless systems provides important functions of neuro-navigation in cranial surgery [18]. The localization process can substantially limit the bone opening size or craniotomy ensuring a safe removal in intra-axial lesions such as ones developed in brain cancer (tumor resection). These systems can be helpful aides in multiple spinal surgeries as well for instance the insertion of pedicle screws in the vertebral column, particularly the thoracic spine. The technology can effectually be implemented at the C1-2 level and cranio-vertebral junction.

Stereotaxic navigation has multiple advantages and accuracy considerations as it provides and effective, safe, and minimally invasive alternatives for different treatments. The technique can be utilized for patients diagnosed with benign, malignant, and functional indications in the central and peripheral nervous systems, involving but not restricted to both primary and secondary tumors. Stereotaxic navigation provides optimum frameless equipment as well with the help of recent advancements in optical and computer hardware as well increasing the surgeon_x0092_s freedom and flexibility during surgical procedures. The improvisation in image-guided surgery have been applied for intraoperative navigational support for management of various neurosurgical approaches (such as craniofacial and otolaryngology issues). From the innovation of stereotaxic frame, different systems have been formed that record patients_x0092_ images to the frame of reference, then track the post-registration condition [17]. These systems involve vision-based optical tracking equipment, stereotaxic articulated arms, magnetic systems, and acoustical systems.

The most important disadvantage of this system is the mechanical association which can be unwieldy and has restricted freedom gradations. While the infrared LED technical prospects provide good accuracy and have ease of movement in the surgical field, there are some minute details that are to be noted. The line of sight between the probe, the charged coupled device cameras, and the microscope should remain unhindered [14]. However, it has been observed that metallic objects in the surgical field can cause disturbance in the magnetic reception.

Stereotaxic navigation is a method of navigation method in neurosurgery and permits the reaching of targets within the brain using high precision. It is a tiny robotic machine with five joints shown in figure 1 that is usually attached to the patient_x0092_s head during brain surgery. It is an instrument in the form of a needle that is movable by way of changing the joint angles settings. As shown in the figure below, the joints are indicated with letters and are regarded as revolute joints. A stereotaxic frame is used in holding the patient_x0092_s head in place during the surgery process. The frame consists of three parts including the frame base, localizer frame, and the passive jointed mechanism. The frame base forms a direct attachment to the head. The localizer frame is in the form of a box with localizers for CT and MR imaging and it attaches to the base. These localizers are called fiducials. The passive jointed mechanism is rigidly attached to the base of the frame [19].

Figure 1: Five-joint mechanism for stereotaxic neurosurgery

In most cases, the three dimensions are: dorso-ventral (y), latero-lateral (x), and rostro-caudal (z). The stereotaxic equipment uses a group of thee synchronized codes (x, y and z) in a reference frame that is orthogonal in nature, or otherwise, a suitable coordinate arrangement, having three coordinates: depth, angle, and antero-posterior location [16]. The navigation device controls clamps that hold the head in position and bars which provide a fixed position for head in positioning to origination and coordination mechanisms. The y, x and z are axial cross sections viewed in the imaging of the patient_x0092_s head. Z is derived from calculating the distance between the oblique rod and horizontal rod of the image cross-section. The x and y coordinates of the image target are obtained using a similar method [19].

Calibration methods entail using formulas to calculate the angle values of the coordinate system. Forward and inverse kinematic analyses are methods used in computing the angle values when the prismatic joints and position as well as needle orientation are given respectively. In mapping the CT/MR coordinate system to the frame coordinate, these formulas will compute the needle tip position [19].

Near Infrared Methods

There are some other non-invasive navigational methods selected for the neurosurgical approaches. Near-infrared methods are one of the essential ones to determine and take into consideration. The technique of near-infrared (NIR) fluorescence imaging has been represented to provide exceptional sensitivity facilitating non-invasive evaluation of both neurosurgical function and architectural arrangements as well. The technique can also identify potential disease markers of dysfunctions [20]. NIR fluorescence imaging along with tomography is involved with administering a fluorescent contrasting element that: has a substantial Stroke_x0092_s shift giving off fluorescence at 800nm of wavelengths or even more; and can be potentially excited at wavelengths of 780nm or more [15].

Because of its sensitivity outcomes, nuclear imaging process with radionuclides sets the clinical standard for molecular imaging techniques. Still, when compared to radionuclides implemented for the imaging process, NIR fluorophores have been observed to provide higher sensitivity for non-invasive, intraoperative imaging [15]. This is due to their capability to be repeatedly stimulated by tissue-penetrating NIR excitation light.

The basis of near infrared fluorescence imaging and tomography is greatly associated with deep tissue sections depending on the low absorbance but high scattering characteristics of tissues in the wavelength of 600-1000nm, causing diffused elaboration and deep parenchymal absorbance. Out of this wavelength set for therapeutic mechanisms, only a small wavelength portion in the NIR region (>750 nm) is optimum for non-invasive imaging in neurosurgery, without the contributing elements of auto-fluorescence.

Trends Development

Surgical robots are found to be expensive. However, they are less expensive when considering the minimal time, they take in the operation room. This will be financially viable in future. Looking at navigational activities as well as patient registration imaging, they are time consuming. There is a likeliness of seeing a speed-up in this process [1]. Tracking systems will continue being valuable in reducing errors and re-registering targets during surgery. Continual development of surgical robots will still take place so as to benefit from the ultrasound, interventional and visual CT/MR data. It is useful information that surgeons and other staffs in the operating room will continue using to achieve augmented reality and predict simulations live [1]. Addressing of footprint minimization will be consistent I future robots. Smaller and light weight robots will be common in future to reduce bulk and mass robots that may not be safer. Tasks that are autonomous will continue increasing as well as more usage of algorithms in performing tasks that detect structures and boundaries that are sensitive will continue to utilized as a measure of warning surgeons. They will also act as measures of modulating the speed of cutting and optimization of applied pressure [1]. The need for navigation systems as well as image data for patients will continue requiring the use of robotic surgery procedures in future to address finer movements including microsurgery for the spine and brain.

Research projects at present are focusing on the significance of three major areas for improvement considering neurosurgical robots. One of them is to increase the overall efficacy and/or accuracy of the conventional stereotaxic navigation and surgical systems; another is to increase the value and importance of the equipment and the last is to further improve the capabilities of human surgeons in the operation theatre [21]. There is a considerable amount of research ongoing to represent how these trends are being vitally identified with scientific development and resourceful techniques. The benefits and added compensations are also being outlined for future patients [22]. Security and patient safety is of utmost value, and may always determine how research is conducted.

Conclusion

Robotic navigation in neurosurgery is inevitably a process that has clearly influenced the application of field with the help of multiple devices that are FDA approved, most commonly in the radiosurgery field. However, it is evident that as the surgical robotics field improvises, a great deal of attention must be given to the details of spinal and brain surgeries to integrate newer and better elements of surgical anatomy. Incorporation of focused and particular technologies can then be modified more feasibly in the surgeon_x0092_s prevailing extremely skillful functional systems.

For the formation of future agility, automation, improvement of capability and feedback of sensory mechanisms, it is of essential importance to operating robots if it can be outlined in the meaning of individual subject. Automated machines that have been implemented widely in neurosurgical assessments are explained in the context professionally. Concentrating on specific solutions associated with central nervous system, the discussion provides recommendations and improvement opportunities for future as well. Efforts to adjust additional arrangement for clinical applications have also been elaborated in a careful manner.

Advancing technologies and strategies for instance virtual reality, haptics, and telemonitoring may additionally combine with the surgical machines to form an innovative environment for assessment and acquisition of operating options with the help of activation of all functionalities that can be done with the automated functions.

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