Are computer numerical control (CNC)-manufactured patient-specific metal templates available for posterior thoracic pedicle screw insertion? Feasibility and accuracy evaluation

Objective: To assess the precision and efficiency computer-assisted surgery navigation of pedicle screw insertion by standardized trainees. Methods From September 2013 to June 2016, 360 thoracic pedicle screws were inserted into 100 patients by standardized trainees (n = 30). Screws on the left side were inserted by hands (control group), while the other side were inserted under the guidance of computer-assistant navigation system (guided group). The insertion time and volume of blood lost by each screw were retrospectively analyzed. The precision ratio was assessed by computerized tomography (CT) scan after operation. Results The time consumed in screw insertion was significantly shorter in the guided group than that in the control group. The blood lost volume was lesser in the guided group. Post-operation CT scan revealed higher precision in the guided group than that in the control group. Conclusion Computer-assistant navigation system facilitates the learning of standardized trainees, and reduces the time-consuming and bleeding in thoracic pedicle screw insertion. Orthodontics training is the most important low-grade physician training in the orthopedic department1,2. Due to the complexity of spinal anatomy, professional required and high risk of spinal surgery, thoracic pedicle screw implantation has become a very demanding technique. Furthermore, the spine surgery learning is not conducive to the trainees. Since 2013, our department started to use the computer-assisted three-dimensional navigation technology to guide the implantation of screws3. We found that the computer-assisted navigation technology has greater advantage when compared with the traditional hand-implanted technology.

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Patient-Specific Templates for Pedicle Screw Insertion in Spinal Fixation Surgery

10.29007/kbf7 ◽

2018 ◽

Author(s):

Mahmoud Hafez ◽

Mohamed Fouda

Keyword(s):

Pedicle Screw ◽

3D Model ◽

Pedicle Screws ◽

Ct Scans ◽

Patient Specific ◽

Scoliosis Surgery ◽

Spinal Fixation ◽

Screw Insertion ◽

Pedicle Screw Insertion ◽

Surgery Patient

The increased use of pedicle screws in scoliosis creates a challenge for accurate and safe placement ofscrew within the pedicle during the scoliosis surgery. Patient-specific templates (PST) is a novelmethod to guide the surgeons for allocating and detecting the positions and trajectories of pediclescrews in scoliosis surgery. Based on CT-scans and according to certain protocol, this technique willallow the surgeon to construct a 3D model of spine and present the stage and vertebrae which containthe most deformed bone. With preplanned surgery on specific software, we can develop an accurateand safe position of pedicle screws and its trajectories. This method has the ability to customize theplacement and the size of each pedicle screw based on the unique morphology and landmarks of thevertebrae.

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Patient-specific template-guided versus standard freehand lumbar pedicle screw implantation: a randomized controlled trial

Journal of Neurosurgery Spine ◽

10.3171/2020.10.spine201383 ◽

2021 ◽

pp. 1-7

Author(s):

José Miguel Spirig ◽

Shayan Golshani ◽

Nadja A. Farshad-Amacker ◽

Mazda Farshad

Keyword(s):

Randomized Controlled Trial ◽

Radiation Exposure ◽

Pedicle Screw ◽

Controlled Trial ◽

Patient Specific ◽

Pedicle Screw Placement ◽

Surgical Time ◽

Screw Insertion ◽

Pedicle Screw Insertion ◽

Randomized Controlled

OBJECTIVE Patient-specific template-guided (TG) pedicle screw placement currently achieves the highest reported accuracy in cadaveric and early clinical studies, with reports of reduced use of radiation and less surgical time. However, a clinical randomized controlled trial (RCT) eliminating potential biases is lacking. This study compares TG and standard freehand (FH) pedicle screw insertion techniques in an RCT. METHODS Twenty-four patients (mean age 64 years, 9 men and 15 women) scheduled consecutively and independently from this study for 1-, 2-, or 3-level lumbar fusion were randomized to either the FH (n = 12) or TG (n = 12) group. Accuracy of pedicle screw placement, intraoperative parameters, and short-term complications were compared. RESULTS A total of 112 screws (58 FH and 54 TG screws) were implanted in the lumbar spine. Radiation exposure was significantly less in the TG group (78.0 ± 46.3 cGycm2) compared with the FH group (234.1 ± 138.1 cGycm2, p = 0.001). There were 4 pedicle screw perforations (6.9%) in the FH group and 2 (3.7%) in the TG group (p > 0.99), with no clinical consequences. Clinically relevant complications were 1 postoperative pedicle fracture in the FH group (p > 0.99), 1 infection in the FH group, and 2 infections in the TG group (p > 0.99). There were no significant differences in surgical exposure time, screw insertion time, overall surgical time, or blood loss between the FH and TG groups. CONCLUSIONS In this RCT, patient-specific TG pedicle screw insertion in the lumbar region achieved a high accuracy, but not better than a standardized FH technique. Even if intraoperative radiation exposure is less with the TG technique, the need for a preoperative CT scan counterbalances this advantage. However, more difficult trajectories might reveal potential benefits of the TG technique and need further research.

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