الفهرس 
SURGICAL TECHNIQUESOnly 14 pages are availabe for public view
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Abstract
S
pine surgeons may use computer assisted surgery to help place implants (such as pedicle screws) during spinal fusion procedures to treat spinal instability caused by degenerative disc disease, deformity, spinal stenosis, spondylolisthesis, fractures, tumors and infection.
The main premise behind CAS is specialized software creates a virtual, 3-D model of the patient’s spine, essentially a digital roadmap or blueprint to help guide the surgeon. During spine surgery, the surgeon matches the patient’s actual spine to the computer’s virtual model displayed on the monitor in the operating room. Much like a GPS system in an automobile, the surgeon is then able to track in real time the position of surgical instruments and implants in relation to the patient’s true anatomy. For this reason, CAS may also be referred to as surgical navigation.
Prior to surgery, the patient undergoes a CT scan, and these images are downloaded in to the navigation computer. The software uses these images to build the virtual, 3-D model of the spine. In a process called registration, the surgeon uses Smart Instruments to match pre-defined points on the 3-D computer model to the patient’s true anatomy. The software uses these points to correlate the position of the patient in real-time with the computer generated 3-D model to create a digital map of the spine.
Rather than sending the patient for a pre-operative CT scan, some surgeons may utilize a 3-D intraoperative imaging device to obtain the images and automatically register the patient’s anatomy in the operating room.
Once registration is complete, the navigation camera tracks the movement and position of Smart Instruments in the surgical field and real-time images of the instruments are displayed on the 3-D model. The surgeon is then able to see the exact position of the instruments, aiding in surgical precision and helping to avoid potential damage to surrounding tissue and structures (such as the spinal cord, nerves and arteries). In spinal fusions, the surgeon may also use the 3-D model to plan the position, length and diameter of pedicle screws, and then navigate instruments to ensure the screws are implanted exactly as planned.
Surgical navigation does not replace the skill of the surgeon. This technology provides the surgeon with real-time guidance in placing implants in the spine where visibility with the human eye may be challenging. Dr. charles Haworth, spine surgeon and Clinical Assistant Professor of Neurosurgery at Duke University, describes how CAS assists him to more precisely place pedicle screws. “It’s like diving a nail down a pencil, without breaking the pencil. It’s that easy using navigation.”
There are several benefits CAS offers both the surgeon and the patient. During conventional spine surgery without the use of surgical navigation, surgeons may take multiple X-ray images to verify the location of instruments and placement of implants throughout the procedure. CAS eliminates the need for repetitive X-ray images, helping to reduce radiation exposure to both the patient and medical team
It provides the surgeon with comprehensive data about the patient’s anatomy to pre-plan for surgery and determine such things as pedicle screw length, diameter and position; potentially saving valuable time and uncertainty in the operating room. In addition to having a computer model of the patient’s spine to reference during surgery, CAS delivers real-time guidance of the positioning of instruments and implants along with the ability to correct potential implant misplacement during surgery.
Additionally, CAS enables minimally invasive procedures by offering the surgeon enhanced visualization of the anatomy, especially when smaller incisions are used.