Technological innovation in neurosurgery & Neurosurgical Medicine
Dr.Shylesh M P is a Consultant Neurosurgeon practicing at Altius Hospital,HBR Layout, Bangalore, with 8 years of experience. He completed his MCh Neurosurgery from the National Institute of Mental Health and Neurosciences (NIMHANS). He has done his MS (General Surgery) from Bangalore Medical College and Research Institute and his MBBS from Vydehi Institute of Medical Sciences and Research Centre in.
The Pace of Change in Medical Practices
Medical practices have evolved since the ancient era and have advanced significantly to the present day. For instance, if we discuss neurosurgery,dating back to prehistoric times,trephination was the surgical procedure primarily used to treat psychic diseases, which was earlier done by creating a hole in the skull using very elementary instruments like sharp stones, knives, chisels &hammer etc. However, advances in medical science has improved by leaps and bound due to the concepts of asepsis,anaesthesia, infection control, antibiotics, blood transfusion, seizure control,imaging etc. Innovations, newer ideas and technological developments began in the medieval times and ushered a revolution in the field of neurosurgery and other medical paradigms too. In contrast, neurosurgery which was deemed extremely risky and dangerous during those days and a task considered next to impossible has had a dramatic refinement, owing to the newer technological advancements, it has become safer and feasible. During olden times, it was a very complex task to remove a brain tumor which involved a serious risk to the patient’s life with terrible mortality rates of about 50 to 70% and causing severe neurological deficits and complications. Currently, due to the available technological ingenuity, and advances in anaesthesia, antiseptics, antibiotics, imaging techniques, neuromonitoring, microsurgeryetc.millions of lives have been saved every day.
Technological Advancements in Neuro Microsurgery: An Incredible Medical Breakthrough
In the past decades, rapid technological advances in the optics and electronics, operating microscopes were introduced into the neurosurgical field which has revolutionized the way surgeries are being performed. Delicate nerves, blood vessels, tumours and other structures which were impossible to be seen by naked eyes were able to be visualized with a superior resolution, higher magnification and better illumination offering better surgical outcomes and better prognosis for the patient and a higher degree of confidence,an excellent 3d perception and ergonomics for the surgeon too.The most breakthrough innovation,the operating microscope is the workhorse behind the micro neurosurgical procedures performed world wide. Addition of fluoresence filters to the scope has made performance of “on table angiograms” possible which is a very essential tool while performing neurovascular surgeries like clipping aneurysms, AVM surgeries etc. Also fluorescence technology has been applied to tumor surgeries where in the tumours are made to light up and stand out in contrast to the surrounding normal brain by injecting fluorescent dyes. This aids in complete and safe resections of brain tumours. Usage of microscopes while performing spinal surgeries has increased the safety and precision and better patient outcome.
Then there's an image guidance systems which are in vogue currently,also known as neuro-navigation systems. Here, the patients preoperative MRI s or CT scans are co-registered with the patients lying on the operative table. This is a magical tool where the surgeon can localize the tumours or areas of interest even being opening up the skull, which helps in preoperative planning, marking skin incisions, deciding the approach and the operative corridors, taking extra precaution in regard to the surrounding vital brain and neurovascular structures and avoid inadvertent damage to them. It literally navigates the surgeon to the area of surgical interest which is why it has become an essential tool in any neurosurgical setup, especially in taking biopsies from very minute tumours and highly eloquent areas of brain including the brain stem. It is also widely used while performing difficult shunt surgeries and placing spinal implants and screws under better precision and confidence.
The next important modality is intra-operative neurophysiological, which uses electrophysiological techniques such as electroencephalography (EEG), electromyography(EMG), Electrocorticography (ECoG) and evoked potentials to monitor the functional integrity of specific neural pathways.An analogy of how an electrician finds a fault in the electrical circuitory of a house by checking the supply and the delivery points, switches and wires–cables can be applied to understand neuro monitoring techniques . By triggering specific points along the neural circuitry using minute electric currents and monitoring the muscle response, current amplitude and frequency, etc the integrity of the neural pathways can be validated using these techniques. Motor evoked potentials (MEP), Somatosencory evoked potentials (SSEP), cranial nerve EMG monitoring, D-waves monitoring are various modalities which are used for neuromonitoring. It can be applied while performing seizure surgeries to localize the epileptic foci, identify motor-sensory cortex while performing brain tumour surgeries using phase reversal techniques, during spinal cord surgeries, brainstem and CP angle surgeries. This is again an indispensable to perform complex cranial and spinal surgeries.
The next big thing is neuromodulation, which is a technique where certain areas of brain are directly stimulated by placing electrodes to modulate the abnormal neuro-excitationby applying feeble electric impulses.For example, in cases of medically refractory Parkinson's disease, obsessive compulsive disorder, dystonia, essential tremors, chronic pain syndromes, chronic depression states, neuralgias etc , in those all lines of medical management has failed the patients can be given the choice of these modalities. It is popularly called as Deep brain stimulation (DBS). Here and electrode is paled in the depth of brain /brain nuclei and connect to a battery which is implanted in the patient chest or abdomen region. It is very effective to treat various movement disorders like parkinson’s disease, tremors, psychologic disorders, cancer pain and chronic pain syndromes.
Endoscopes were used in various fields, including surgical gastroenterology, urology, gynecology, orthopaedics etc. Endoscopes are now used in neurosurgery as well, where they are referred to as keyhole surgeries. Rather than making large openings in the skull and approaching the brain, a small key hole is made through which an endoscope is introduced and tumours are removed or the pathology is corrected. This offer smaller postoperative scars, less blood loss , less pain, lesser tissue damage and faster recovery for the patient.They are used in performing pituitary and other skull base procedure, performing Endoscopic third ventriculostomies (which are currently desirable alternatives for ventriculoperitoneal shunts), even biopsies can be taken using endoscopes. This is applicable even for spinal surgeries as well through which discectomy, spinal tumours, deformities can be corrected using minimally invasive techniques.It has really turned out to be a boon for pituitary and skull base surgeons where a scarless incision can be performed through natural orifice like the nose.
Neural Technology- Frontiers in Neuro Science
Neurotechnology is a assembly of methods and and instruments that enable a direct connection of technical components with the nervous system to monitor or modulate neural activity.Also referred to as the “Brain –computer interface”, goal of this is to use the neural activity signals , analyze and feed it to a external device such as a neuroprosthetic (artificial fingers/hand etc), or for neuromodulation- to normalize abnormal brain activities in various degenerative and other neurological disorders, to improve cognitive abilities. It can also be used as a powerful research tool to study the human “psyche” - intellect, behavior, personalities, emotions, consciousness, memory, skills, language etc. Off hand, it also used for commercial purpose to understand human preferences and desires and applied in the so called- “neuro-marketing”, advertisements and gaming industry as well. Therapeutically it is used for study and cure of patients with depression, strokes, memory disorders like Alzheimer’s disease, Parkinson’s disease. Sleep disorders and also to study various pharmaceutical drug effects on the brain.Transcranial magnetic /electrical stimulation, neuromonitoring , neuroprosthetices, , DBS are all part of this entity called neurotechnology.
Technology Application in Brain Surgery: Challenges & Risks
Cost & Availability
Surgeons can now operate on portions of the brain without making a single incision in or near the head, thanks to advances in medical technology. However, the main concern is still seen in the area of cost &availability.Technology is progressing, but the main challenge is that it is not available at all hospitals or institutions owing to its high import and patent costs, as well as high maintenance costs & in between there is a lot of research involved, which is why it is so costly. For starters, it serves as a barrier between technology and usage.
Precision & Accuracy
Precision and accuracy are the second characteristics. Although technology improves accuracy and precision, there are some disadvantages to using neuro navigation due to something called the “Brain shift “ that happens once the local anatomy changes due to CSF release, brain shrinkage, tumour removal, change in patient position. All this causes the accuracy and precision to go for a toss and intraoperative dilemma.
With respect to neuromonitoring , even subtle physiological changes like a drop in blood pressure during surgery, temperature fluctuation, depth of anesthesia and other physiological changes-interpretation of the readings become difficult and poses challenge to the surgeon and the anesthetic team.
Lack of expertise & Trained Hands
While using neurophysiological monitoring, there may be some issues with the wires or cables, or with the patient parameters itself, causing electrical currents to be picked up improperly. Therefore, during surgery, the surgeon sometimes goes into a dilemma whether to remove the tumour or not which definitely can cause more harm to the patient. And another challenge is using neuro physiological monitoring and neuronavigation technology that requires a lot of expertise and trained hands for using these instruments, that has been very difficult in developing countries like India &underdeveloped countries. Minimally invasive surgeries like endoscopy have steep learning curves.
High Maintenance Cost& Availability
High maintenance costs while procuring the instrument is one thing, maintaining these instruments in countries such as India is another.The use of neuro navigation presents a significant challenge because it requires high-quality thin slice mages three-tesla or four-tesla MRI, which are not widely available in India. Thus, these are the difficulties that a neurosurgeon or neurologist may face while practising with technology.
The Rise of 3D Technology in Neuro Surgery
In neurosurgery, 3D technology provides a practical and anatomically accurate means of producing patient-specific and disease-specific models that provide depth to the operating surgeon. As a result, a 2Dimage captured as a scan with a VR detector is converted into a 3D reconstruction of the tumour even without touching it. With the help of 3D printing technology, you can determine the shape of the tumour as well as all of the important structures that surround it. This is the advantage of 3D technology; all of this can be known beforestarting with the surgery. As a result, it provides a different perspective that aids in preoperative planning for the surgeon on which approach to take to reach the safest entry point. Hence, highly accurate and customized implants and cranioplasty meshes can be prepared using this 3D technology. Also. 3D printing technology can be applied in manufacturing and designing precision surgical instruments requires for delicate surgeries.
Advantages & Disadvantages of Neuro Navigation in the surgical management- An Overview
Neuronavigation is a boon to the current era of Neurosurgeons which aids in accurate preoperative localization, planning skin incisions, choosing surgical approach and corridors, to keep track of surrounding vital structures,. It gives and extra edge to the surgical team and navigates the safely to the right area of interest and keeps them on track during surgery.
There are some disadvantages to using neuro-navigation due to something called the “Brain shift “ that happens once the local anatomy changes due to CSF release, brain shrinkage, tumour removal, change in patient position. All this causes the accuracy and precision to go for a toss and intraoperative dilemma. These are high end tools not available or affordable by all hospitals also the incurring maintenance cost and requirement of trained professionals to handle the equipments are additional hurdles that have be borne in mind.
A Glimpse on the Future Ahead
Over the last 50 years, five major technology clusters have been identified: image guidance devices, clinical neurophysiology devices, neuromodulation devices, operating microscopes, and endoscopes. Furthermore, the Diffusion of Innovations theory could be used to describe the growth pattern of these technology clusters over time. Image guidance and neuromodulation devices were discovered to be in an exponential growth phase, and as such can be expected to have a growing influence in the future of operative neurosurgery. The same methodology may be used in future studies to assess more specific technology clusters in order to forecast their potential influence.