Sharif Digital Repository

Spinal instrumentation with pedicle screws has become a widespread surgical procedure in the treatment of spinal disease. The traditional way of placing pedicle screws is to use the anatomical landmarks which at many times can be a best guess resulting in breaches of the pedicle and causing neurological injuries. Additional modalities used include the intra-operative fluoroscopy or navigation systems, which results in radiation exposure and more intra-operative time. In order to solve the technical problems, a pedicle screw navigation template that guarantees the correct implantation position and direction of vertebral pedicle screws, can be used. Compared to pedicles in the lumbar spine,... 

Fusion surgery or fixation of vertebrae in the spine is used to treat scoliosis, fractures, infections, tumors, spinal cord injuries, and disc herniation. In this type of surgery, two or more vertebrae are connected by special screws called pedicle screws to eliminate movement between the vertebrae. Given the serious risks of spinal fusion surgery, if the slightest mistake is made at the entry point or angle of the screw inside the vertebrae, the risk of spinal cord injury is very high, which is one of the complications of fusion surgery. Therefore, in order to increase the accuracy of screw placement, patient-specific template guides are used as drill guides in this operation. For this... 

We have recently designed/fabricated novel bilateral vertebra- and patient-specific drill guides for pedicle screw (PS) placements and tested their accuracy for both nondeformed and deformed thoracic spines. PS placement deviations from their preplanned positions significantly reduced when guide template were used; the success rate improved from ~72% (freehand placements) to 94% (guided placements). In the present study, we aim to use finite element (FE) analyses to evaluate the pull-out strength of these PSs inserted via either the freehand technique or our drill-guide templates. Two 3D-printed T1-T12 thoracic models of a severe scoliosis patient with a 47° thoracic dextro-scoliotic curve... 

One of the most common spinal surgeries involves spinal fusion or vertebral fixation, which is used to treat various conditions such as intervertebral disc disease, scoliosis (lateral deviation of the spinal column), fractures, infections, or the presence of tumors in the spinal column. In this surgical procedure, the use of pedicle screws and titanium rods prevents motion and friction between two vertebrae. Screws may enter the vertebrae in the wrong position and angle, causing bone weakening, rupture of nerve roots or blood vessels, weakness or lack of sensation in some parts of the body, spinal cord injury, and in severe cases, paralysis of the patient. For this reason, fusion surgery is...