Computer - Navigated Surgery

The advent of Image-guided Surgery is a major advancement in Orthopedic Surgery. It is available only in limited centers around the world and St. Luke’s Medical Center was the first in the Philippines that acquired it for orthopedics. The whole system was introduced in 2004 and has been in use for surgeries involving the brain and spine, head and neck region, and joint replacement.

The technology being used in computer-assisted navigation surgery is similar to the location and directional tracking systems being utilized in air and sea transportation, i.e. GPS system. The Vector Vision System is equipped with two cameras that function as satellites that detect images over the operating field. The anatomy of the operative site is assessed and a three-dimensional image is generated into the computer, either computed-tomography or fluoroscopy-based. As the surgeon utilizes various instruments, the camera calculates their position – accuracy and precision – and transfers data into the computer. Values are generated from placement of these instruments thus decreasing surgical errors.

The two main advantages of using navigational surgery are safety for the patient and surgeon and high surgical success rates.

Utilization in spine surgery allows the surgeon to perform various procedures including osteotomies, vertebroplasties, scoliosis correction and pedicle screw placement in spine trauma and degenerative conditions with greater accuracy and precision – thus, reducing radiation exposure. Computed tomography, fluoroscopy or combined images are generated from the computer giving the surgeon comprehensive information and three-dimensional view of the spine. This enhances the orientation and widens the view for surgical approaches. Pre-calibrated instruments enable the surgeon to navigate more precisely and efficiently to calculable target positions with minimal exposure.

In total knee replacement surgery, a patient-specific bone model is created intra-operatively providing a template for determining the amount of bony resection on the femur and tibia, positioning of the implants and assessing alignment of the mechanical axis. With continuous tracking of the surgical instruments and kinematic software, these provide the surgeon with absolute values on varus and valgus positions, symmetry of flexion and extension gap joint spaces and prosthesis rotation in the axial plane. With these advantages, surgical errors are detected and corrected earlier during the surgery thus improving outcomes.

With a three-dimensional template of the hip, ideal implant size and position can be precisely determined and accurately placed thus increasing confidence of the surgeon. Image-guided leg length control and analysis of range of motion prevents and minimizes post-operative complications such as limb shortening and dislocations. Over-all patient advantage is providing a painless functional limb.

Radiation-exposure is a major risk factor to both patient and surgeon during fracture reduction and fixation especially with fluoroscopic-guided surgery. With computer-navigation, visualization and manipulation of multiple fluoroscopic images across different planes simultaneously greatly reduces the over-all number of images needed for surgery. Motion of fracture fragments is viewed in real time aiding the surgeon in reduction. The optimal size and position of various fixation devices such as intra-medullary nails, compression plates and inter-locking screws are planned prior to their placement. These help reduce operative time and radiation exposure.