The brain show: viewing system provides surgical staff with front-row seats.

The surgical suite is not the roomiest shop floor for working. It's not intended to be--most procedures are on a single region of the patient, precluding need for excess movement. To serve the surgeon and staff, the remaining floor space is taken up by equipment trays and support systems, like the anesthesia cart.

There are some surgeries, however, that require the active participation of more than one surgeon. The difficulty increases further when the procedure involves microsurgery, and the field of operation is reduced to the area seen through a microscope. More and more procedures are being handled through image-guided surgery, including various brain surgery approaches, particularly planning the craniotomy, navigation in deep seated tumors, skull base surgery and acoustic neuromas. In the spine, image-guided surgery has been used in the placement of pedicle screws, lateral mass screws and transarticular C1-2 screws. The result is that the reduced invasiveness in turn reduces the recovery time for the patient. Many return home the same day.

Computers in surgery

Image-guided surgery developed from the idea that a computer could be employed to track a surgical instrument during a procedure, constantly representing the tool's position relative to diagnostic images stored in the computer's database. It serves as a confirmation to surgeons in the case of abnormal anatomy, undifferentiated tumors, or tumors located in critical areas (e.g. near the motor cortex). During the operation, the surgeon uses instruments connected to the position sensor to view the images at the location that he is touching. For example, during a brain operation, the surgeon may wish to confirm that a structure is part of the tumor he is trying to remove. He will touch the pointer to the anatomy in question in the patient's brain and examine the system screen. Crosshairs will be shown on the image corresponding to the location that the surgeon is touching.

Another aspect being explored in image-guided surgery comes from the issue that while a patient's skull may be rigidly clamped, the brain tissue is a non-rigid mass. Systems that rely on the assumption that a pre-operative MR image accurately reflects the shape of the brain during surgery are insufficient for a broad range of neurosurgical tasks. Techniques are being developed that use ultrasound images of the brain, collected during the surgery, to track the distortion of the brain tissue. Once the distortion has been measured, it is used to warp the pre-operative MR images such that they accurately reflect the shape of the brain during surgery.

Additionally, image-guided surgery is used as a targeting and control tool to provide focused radiology treatments with pinpoint accuracy. With this navigation technology functioning like a GPS system, target volumes of tumors can be localized with great accuracy, allowing surgeons to attack the tumor with high-precision radiation.

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