Neuronavigation

Neuronavigation is a precision-based surgical technology performed with the help of a group of computer-assisted systems that enable the neurosurgeon to navigate within the confines of the human skull and vertebral column. It is also the latest in image-guided and non-invasive neurosurgical techniques. It provides orientation to the neurosurgeon during surgery to map a precise and suitable surgical plan. Neurosurgeons require high levels of accuracy while they perform various neurosurgical techniques, mainly because they operate around the brain, nerves, and the spinal column

Currently, neuronavigation shows a lot of promise, as it is being considered as the next big evolutionary step in the field of stereotactic surgery. This technique is also cost-effective and user-friendly. It is also a very useful prop and compliment to the neurosurgeons knowledge and expertise in relation to the anatomy of the brain, nerves, and spinal column.

History of neuronavigation:

Neurosurgeons have been using the neuronavigation technology for nearly 30 years. The development of state-of-the-art imaging techniques, robotics, space, and electronic technologies has together led to the welcome advent of neuronavigation during neurosurgery. The user-friendly, cost-effective, and precision-based nature of this technique has led to its emergence as an indispensable tool in the domain of neurosurgery. In fact, it has consistently replaced the older frame-based stereotactic surgical procedures in most neurosurgical set-ups. It is also expected to provide further benefits in this field due to progressive integration of intra-operative CT, USG, and MR imaging and robotic systems.

How does neuronavigation work?

The neuronavigator system consists of a pointer or microscope based system to achieve image guidance during surgery. Fiducial markers are attached to the patient’s head one day before surgery, by using a 3D low-angle shot sequence and open MRI scanner. Fiducial markers are objects placed in the field of vision or image system that appear in images as pointers or markers. These images are then transferred onto the neuronavigation computer workstation. During surgery the patient’s head is then fixed onto the head holder on the neuronavigator. The fiducial markers on the patient’s head are then registered onto the system by the surgeon, using the stereotactic pointing device available on the system.

Neuronavigation for spinal surgery uses a slightly different technique, as the spine is much more flexible than the skull. Skin markers aren’t used for spinal surgery, but surface-matching and paired-point techniques are used instead to mark the characteristic anatomical landmarks of the vertebrae. The frame of the navigator is then fixed onto a spinous process of a vertebra within the surgical area.

The microscopes and the images within the system work together with the rest of the equipment to register and process these images to provide an accurate mechanical mapping of the neuroanatomy of the patient. Additionally, the neuronavigator also enables Magnetic resonance imaging during surgery without having to move the patient. This facility has further helped improve accuracy during neurosurgery.

Clinical uses of neuronavigation:

Neuronavigation is used in a variety of neurosurgeries to enhance the outcome of surgery and level of patient recovery. Here’s a comprehensive list of surgeries that have been done with the use of neuronavigation systems.

Localization of small intracranial lesions or tumors is the most frequently performed surgical technique using neuronavigation systems:

  • Skull related surgery
  • Intra cerebral biopsies and intracranial endoscopy
  • Functional neurosurgery
  • Epilepsy surgery, to localize and insert deep-brain electrodes within the hippocampus.
  • Extra pyramidal movement disorders
  • Surgery for Parkinson’s disease
  • Colloid cyst removals
  • Decompression of Superior Orbital Fissure Fracture
  • Insertion of transpedicular screws in the cervical, thoracic, and lumbar spine

Neuronavigation helps the neurosurgeon calculate and localize small lesions within the skull and spinal column accurately, thus increasing the confidence of the neurosurgeon and the outcome of the surgery. This one important system has certainly changed the face of neurosurgery for the better, and is predicted to progressively multiply the successes of neurosurgery by manifold. In addition, the entry of the latest robotic technology is believed to give neuronavigation an enormous boost in the years to come.

References:

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3428645/

http://www.neurologyindia.com/article.asp?issn=0028-3886;year=2002;volume=50;issue=3;spage=244;epage=55;aulast=Ganslandt#ft26

http://www.ncbi.nlm.nih.gov/pubmed/19722813