Dextroscope
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The Dextroscope is a medical equipment system that creates a
virtual reality Virtual reality (VR) is a Simulation, simulated experience that employs 3D near-eye displays and pose tracking to give the user an immersive feel of a virtual world. Applications of virtual reality include entertainment (particularly video gam ...
(VR) environment in which surgeons can plan
neurosurgical Neurosurgery or neurological surgery, known in common parlance as brain surgery, is the medical specialty that focuses on the surgical treatment or rehabilitation of disorders which affect any portion of the nervous system including the brain, s ...
and other surgical procedures. The Dextroscope is designed to show a patient's 3D anatomical relationships and
pathology Pathology is the study of disease. The word ''pathology'' also refers to the study of disease in general, incorporating a wide range of biology research fields and medical practices. However, when used in the context of modern medical treatme ...
in great detail. Although its main purpose is for planning surgery, the dextroscope has also proven useful in research in
cardiology Cardiology () is the study of the heart. Cardiology is a branch of medicine that deals with disorders of the heart and the cardiovascular system. The field includes medical diagnosis and treatment of congenital heart defects, coronary artery di ...
, radiology and medical education.


History

The Dextroscope started as a research project in the mid-90s at th
Kent Ridge Digital Labs
research institute (part of Singapore's
Agency for Science, Technology and Research The Agency for Science, Technology and Research (A*STAR) is a statutory board under the Ministry of Trade and Industry of Singapore. The agency supports R&D that is aligned to areas of competitive advantage and national needs for Singapor ...
(A*STAR)). It was initially named the Virtual Workbench and underwent commercialization in 2000 by the company Volume Interactions Pte Ltd with the name Dextroscope. The Dextroscope was selected in 2021 by A*STAR as one of the 30 innovations and inventions that pushed scientific boundaries, made an economic impact or improved lives over its 30 years history
A*STAR@30: 30 Innovations and Inventions Over Three Decades
. The Dextroscope was designed to be a practical variation of Virtual Reality which introduced an alternative to the prevalent trend of full immersion of the 1990s. Instead of immersing the whole user into a virtual reality, it just immersed the neurosurgeon into the patient data.


Description

The Dextroscope allows its user to interact intuitively with a
Virtual Patient The term virtual patient is used to describe interactive computer simulations used in health care education to train students on clinical processes such as making diagnoses and therapeutic decisions. Virtual patients attempt to combine modern tech ...
. This Virtual Patient is composed of computer-generated 3D multi-modal images obtained from any
DICOM Digital Imaging and Communications in Medicine (DICOM) is a technical standard for the digital storage and Medical image sharing, transmission of medical images and related information. It includes a file format definition, which specifies the str ...
tomographic data including CT,
MRI Magnetic resonance imaging (MRI) is a medical imaging technique used in radiology to generate pictures of the anatomy and the physiological processes inside the body. MRI scanners use strong magnetic fields, magnetic field gradients, and rad ...
, MRA, MRV, functional MRI and CTA,
PET A pet, or companion animal, is an animal kept primarily for a person's company or entertainment rather than as a working animal, livestock, or a laboratory animal. Popular pets are often considered to have attractive/ cute appearances, inte ...
,
SPECT Single-photon emission computed tomography (SPECT, or less commonly, SPET) is a nuclear medicine tomographic imaging technique using gamma rays. It is very similar to conventional nuclear medicine planar imaging using a gamma camera (that is, ...
and
Tractography In neuroscience Neuroscience is the scientific study of the nervous system (the brain, spinal cord, and peripheral nervous system), its functions, and its disorders. It is a multidisciplinary science that combines physiology, anatomy, ...
. The Dextroscope can work with any multi-modality combination, supporting polygonal meshes as well. The surgeon sits at the Dextroscope 3D interaction console and manipulates the Virtual Patient using both hands, similar to real life. Using
stereoscopic Stereoscopy, also called stereoscopics or stereo imaging, is a technique for creating or enhancing the illusion of depth in an image by means of stereopsis for binocular vision. The word ''stereoscopy'' derives . Any stereoscopic image is ...
visualisations displayed via a mirror, the surgeon sees the Virtual Patient floating behind the mirror but within easy reach of the hands. The surgeon uses flexible 3D hand movements to rotate and manipulate the object of interest. The Dextroscope allows virtual segmentation of organs and structures, making accurate 3D measurements, etc. In one hand the surgeon holds a handle with a switch that, when pressed, allows the 3D image to be moved freely as if it were an object held in real space. The other hand holds a pencil shaped
stylus A stylus is a writing utensil or tool for scribing or marking into softer materials. Different styluses were used to write in cuneiform by pressing into wet clay, and to scribe or carve into a wax tablet. Very hard styluses are also used to En ...
that the surgeon uses to select tools from a virtual control panel and perform detailed manipulations on the 3D image. The surgeon does not see the stylus, handle or his/her hands directly, as they are hidden behind the surface of the mirror. Instead he/she sees a virtual handle and stylus
calibrated In measurement technology and metrology, calibration is the comparison of measurement values delivered by a device under test with those of a calibration standard of known accuracy. Such a standard could be another measurement device of known ...
to appear in exactly the same position as the real handle and stylus. The virtual handle can serve as a drill tool, measurement tool, cutter, etc. The Dextroscope allows surgeons to interact with and manipulate the Virtual Patient, such as simulating inter-operative viewpoints or the removal of bone and soft tissue. The surgeon is able to reach inside and manipulate the image interior.


Virtual tools

The Dextroscope provides virtual tools to manipulate the 3D image. The surgeon can use them within the virtual person to extract surgically relevant structures like the
cortex Cortex or cortical may refer to: Biology * Cortex (anatomy), the outermost layer of an organ ** Cerebral cortex, the outer layer of the vertebrate cerebrum, part of which is the ''forebrain'' *** Motor cortex, the regions of the cerebral cortex i ...
or a
tumor A neoplasm () is a type of abnormal and excessive growth of tissue. The process that occurs to form or produce a neoplasm is called neoplasia. The growth of a neoplasm is uncoordinated with that of the normal surrounding tissue, and persists ...
, extract
blood vessel Blood vessels are the tubular structures of a circulatory system that transport blood throughout many Animal, animals’ bodies. Blood vessels transport blood cells, nutrients, and oxygen to most of the Tissue (biology), tissues of a Body (bi ...
s, or to adjust the color and transparency of displayed structures to see deep inside the patient. The surgeon can simulated the removal of bone using a simulated skull drilling tool. Typical structures that can be segmented are tumors, blood vessels,
aneurysm An aneurysm is an outward :wikt:bulge, bulging, likened to a bubble or balloon, caused by a localized, abnormal, weak spot on a blood vessel wall. Aneurysms may be a result of a hereditary condition or an acquired disease. Aneurysms can also b ...
s, parts of the skull base, and
organs In a multicellular organism, an organ is a collection of tissues joined in a structural unit to serve a common function. In the hierarchy of life, an organ lies between tissue and an organ system. Tissues are formed from same type cells to a ...
. Segmentation is done either automatically (when the structures are demarcated clearly by their outstanding image intensity - such as the cortex) or through user interaction (using for example an outlining tool to define the extent of the structure manually). A virtual ‘pick’ tool allows the user to pick a segmented object and uncouple it from its surroundings for closer inspection. A measurement tool provides accurate measurement of straight and curving 3D structures such as the
scalp The scalp is the area of the head where head hair grows. It is made up of skin, layers of connective and fibrous tissues, and the membrane of the skull. Anatomically, the scalp is part of the epicranium, a collection of structures covering th ...
, and measure angles, such as those between vessels or bony structures (for example, when planning the insertion of a screw into the spine).


Neurosurgery planning – case studies and evaluations

The use of the Dextroscope has been reported for several neurosurgical clinical scenarios; -
cerebral arteriovenous malformation A cerebral arteriovenous malformation (cerebral AVM, CAVM, cAVM, brain AVM, or BAVM) is an abnormal connection between the arteries and veins in the brain—specifically, an arteriovenous malformation in the cerebrum. Signs and symptoms The mos ...
s -
aneurysms An aneurysm is an outward bulging, likened to a bubble or balloon, caused by a localized, abnormal, weak spot on a blood vessel wall. Aneurysms may be a result of a hereditary condition or an acquired disease. Aneurysms can also be a nidus ( ...
Wong GK, Zhu CX, Ahuja AT, Poon WS: Craniotomy and clipping of intracranial aneurysm in a stereoscopic virtual reality environment" ''Neurosurgery'' 2007; 61: 564-568 - cranial nerve decompression (in cases of trigeminal neuralgia and hemifacial spasm) -
meningiomas Meningioma, also known as meningeal tumor, is typically a slow-growing tumor that forms from the meninges, the membranous layers surrounding the brain and spinal cord. Symptoms depend on the location and occur as a result of the tumor pressing ...
(convexity, falcine or parasagittal) -
ependymoma An ependymoma is a tumor that arises from the ependyma, a tissue of the central nervous system. Usually, in pediatric cases the location is intracranial, while in adults it is spinal. The common location of intracranial ependymomas is the floor ...
s or
subependymoma A subependymoma is a type of brain tumor; specifically, it is a rare form of ependymal tumor. They are usually in middle aged people. Earlier, they were called subependymal astrocytomas. The prognosis for a subependymoma is better than for most ...
s - craniopagus twin separationGoh, K.Y.C., 2004. Separation surgery for total vertical craniopagus twins. Child’s Nervous System 20, 567–575. - transnasal approaches - key-hole approaches -
epilepsy Epilepsy is a group of Non-communicable disease, non-communicable Neurological disorder, neurological disorders characterized by a tendency for recurrent, unprovoked Seizure, seizures. A seizure is a sudden burst of abnormal electrical activit ...
- and a great variety of deep-brain and
skull base The base of skull, also known as the cranial base or the cranial floor, is the most Anatomical terms of location#Superior and inferior, inferior area of the human skull, skull. It is composed of the endocranium and the lower parts of the Calvaria ...
tumors (
pituitary adenomas Pituitary adenomas are tumors that occur in the pituitary gland. Most pituitary tumors are benign, approximately 35% are invasive and just 0.1% to 0.2% are carcinomas.craniopharyngiomas A craniopharyngioma is a rare type of brain tumor derived from pituitary gland embryonic tissue that occurs most commonly in children, but also affects adults. It may present at any age, even in the prenatal and neonatal periods, but peak inciden ...
, arachnoid cysts,
colloid cysts A colloid cyst is a non-malignant neoplasm, tumor in the brain. It consists of a gelatinous material contained within a membrane of epithelial tissue. It is almost always found just posterior to the foramen of Monro in the anterior aspect of the ...
, cavernomas ,
hemangioblastoma Hemangioblastomas, or haemangioblastomas, are vascular tumors of the central nervous system that originate from the vascular system, usually during middle age. Sometimes, these tumors occur in other sites such as the spinal cord and retina. They m ...
s,
chordoma Chordoma is a rare slow-growing neoplasm (cancer) that arises from cellular remnants of the notochord in the bones of the skull base and spine. The evidence for the notochordal origin of chordoma is the location of the tumors (along the neuraxis ...
s, epidermoids,
gliomas A glioma is a type of primary tumor, primary Neoplasm, tumor that starts in the glial cells of the Human brain, brain or spinal cord. They are Malignancy, malignant but some are extremely slow to develop. Gliomas comprise about 30% of all brain ...
, jugular
schwannomas A schwannoma (or neurilemmoma) is a usually benign nerve sheath tumor composed of Schwann cells, which normally produce the insulating myelin sheath covering peripheral nerves. Schwannomas are homogeneous tumors, consisting only of Schwann cells ...
, aqueductal stenosis, stenosis of Monro foramen,
hippocampal sclerosis Hippocampal sclerosis (HS) or mesial temporal sclerosis (MTS) is a neuropathological condition with severe neuronal cell loss and gliosis in the hippocampus. Neuroimaging tests such as magnetic resonance imaging (MRI) and positron emission tomogr ...
). Brain and spine pathology, such as
cervical fracture A cervical fracture, commonly called a broken neck, is a fracture of any of the seven cervical vertebrae in the neck. Examples of common causes in humans are traffic collisions and diving into shallow water. Abnormal movement of neck bones or pie ...
s of the spine,
syringomyelia Syringomyelia is a generic term referring to a disorder in which a cyst or cavity forms within the spinal cord. Often, syringomyelia is used as a generic term before an etiology is determined. This cyst, called a syrinx, can expand and elongate ...
, and sacral nerve root neurinomas have been evaluated. For other uses of the Dextroscope in neurosurgery refer to .


Other surgical specialties

The Dextroscope has been applied also outside of neurosurgery to benefit any patient presenting a surgical challenge: an anatomical or structural complexity that requires planning of the surgical (or interventional) approach, for example,
ENT Ents are giant humanoids in J. R. R. Tolkien's fantasy world of Middle-earth who closely resemble trees; their leader is Treebeard of Fangorn forest. Their name is derived from an Old English word for "giant". The Ents appear in ''The Lord ...
orthopedic, trauma and cranio-facial surgery, cardiac surgery and
liver resection Hepatectomy is the surgical resection (removal of all or part) of the liver. While the term is often employed for the removal of the liver from a liver transplant donor, this article will focus on partial resections of hepatic tissue and hepatop ...
.


Dextroscope and diagnostic imaging

Dextroscope is not just for surgeons – radiologists use it, too. The rapid growth in multi-modal diagnostic imaging data routinely available has increased their workload tremendously. Using the Dextroscope, radiologists can reconstruct multimodal models from high volumes of 2D slices – hence facilitating a better understanding of the 3D anatomical structures and helping with the diagnosis. Furthermore, the Dextroscope virtual reality environment helps bridge the gap between radiology and surgery - by allowing the radiologist to easily demonstrate to surgeons important 3D structures in a way that surgeons are familiar with.
This demonstration capability makes it also useful as a base for medical educators in which to convey 3D information to students. In order to reach a larger group of people in a classroom or auditorium, a version was manufactured called Dextrobeam. The Dextroscope was installed, (among other medical and research institutions) at:


Dextroscope in the operating room: DEX-Ray

The Dextroscope was a pre-operative planning system which created 3D patient-specific virtual models. To bring the patient data into the operating room, in particular to neurosurgery, the DEX-Ray
augmented reality Augmented reality (AR), also known as mixed reality (MR), is a technology that overlays real-time 3D computer graphics, 3D-rendered computer graphics onto a portion of the real world through a display, such as a handheld device or head-mounted ...
neurosurgical navigation system was developed in 2006-2008. DEX-Ray overlaid 3D virtual patient information over a video stream obtained from a proprietary handheld tracked video probe designed by the company. This allowed image guidance by displaying co-registered planning data over the real images of the patient seen by the video camera, so that the clinician had 'see-through' visualization on the patient's head, and helped plan the craniotomy and guide during the intervention. The DEX-Ray was clinically tested at th
Singapore National Neuroscience Institute
(Singapore) and at th
Hospital Clinic Barcelona
(Spain). It was not released as a commercial product.


Commercialization

The Dextroscope and Dextrobeam were products of Volume Interactions Pte Ltd (a member of th
Bracco Group
, a company spun-off from th
Kent Ridge Digital Labs
research institute in Singapore. They received USA FDA 510(K) - class II (2002) clearance, CE Marking - class I (2002), China SFDA Registration - class II (2004) and Taiwan Registration - type P (Radiology) (2007). For a comprehensive overview of the Dextroscope refer to the
Springer International Publishing Springer Nature or the Springer Nature Group is a German-British academic publishing company created by the May 2015 merger of Springer Science+Business Media and Holtzbrinck Publishing Group's Nature Publishing Group, Palgrave Macmillan, and Mac ...
book chaper.


References

{{Reflist, 3 Human–computer interaction Virtual reality Neuroimaging software Medical education