Operative Effect Comparison of Flexible Drill Guiding vs. Traditional Drill Guiding Template for Lower Cervical Pedicle Screw Insertion: A Retrospective Analysis

Accuracy and Safety Assessment of Subaxial Cervical Pedicle Screw Instrumentation: A Systematic Review

BACKGROUND CONTEXT

Given increasing use of both cervical pedicle screw (CPS) fixation in the subaxial cervical spine (C3-C7) and emerging navigation technologies, a quantitative profile of safety and accuracy remains wanting. Compared with lateral mass instrumentation of this region, CPS fixation shows superior biomechanical properties but poses higher risk of complications because of the narrow cervical pedicle width and proximity to neurovascular structures.

PURPOSE

This systematic review quantifies the accuracy and safety of all types of subaxial CPS insertion, with or without navigation or template-based methods, to weigh the strengths and limitations of each technique.

STUDY DESIGN

Systematic review according to PRISMA guidelines.

PATIENT SAMPLE

Patients who underwent CPS instrumentation since its introduction.

OUTCOME MEASURES

Primary and secondary outcomes in our review included pedicle screw breach in the subaxial cervical spine determined on intra- or postoperative imaging, and screw-related operative complications, respectively.

METHODS

Following the PRISMA guidelines, our literature search of PubMed, Cochrane, and Scopus databases identified 3,312 clinical studies (1980-2024) using subaxial CPS that assessed for screw accuracy. After full-text analysis, data extracted included number of CPS, level of placement, number of patients, indications, insertion techniques, accuracy assessment method, classification of accuracy, breach rate, complication rate, and study origin.

RESULTS

The 73 studies included in final analysis from Asia (80%), Europe (12%) and North America (8%) yielded 14,118 CPS in 3,342 patients (1999-2024). Accuracy rates were 85.3% for 10,108 CPS placed with non-navigated techniques (free-hand and fluoroscopy), 82.7% for 3,067 with navigation techniques, and 96.3% for 943 CPS placed using 3D templates. Complication rates were 1.1%, 2.1%, and zero, respectively.

CONCLUSION

Our comprehensive review of more than 14,000 subaxial CPSs inserted found rates of high 84% overall accuracy and low 1.2% perioperative complications (i.e., attributed to a misplaced screw). With biomechanical advantages superior to lateral mass screws, our quantitative findings support consideration for CPS instrumentation in select patients by experienced surgeons.

Cervical pedicle screw placement with patient-specific 3D-printed guides: accuracy and safety in a clinical experience

PURPOSE

Cervical pedicle screw (CPS) instrumentation offers significant biomechanical advantages compared to lateral mass or transarticular fixation. Nonetheless, malpositioning complications constitute a relevant concern. Customized patient-specific 3D-printed templates have been developed to improve CPS placement accuracy and safety. The aim of this study is to present our experience with this surgical technique and its accuracy and safety in a clinical setting.

METHODS

This single-center retrospective observational study of prospectively collected data included patients undergoing CPS fixation surgery using a patient-specific 3D template guide system. All patients underwent a 3D-volumetric high-resolution CT scan of the cervical spine for preoperative surgical planning. Postoperative CT scans were used to evaluate pedicle perforation, CPS trajectories, and deviations between the planned and the actual screw position.

RESULTS

A total of 115 CPS were implanted in 25 patients, with 107 (93.1%) of the screws completely placed inside the pedicle. Cortical breach within 2 mm was observed in 8 (6.9%) cases, with no cases of more severe pedicle infractions or perioperative neurovascular complication. No differences of CPS accuracies were found between each metameric fusion level, and between monolateral or bilateral templates. Mean total deviations were 0.75 mm vertically and 0.51 mm horizontally at the screw entry point, and 0.72 mm vertically and horizontally at the narrowest pedicle point. Mean total sagittal and transverse angular deviations were 2.94° and 3.04°, respectively.

CONCLUSION

Cervical pedicle screw placement using patient-specific guides is safe and accurate, supporting the feasibility of this technique in posterior cervical spine fusion surgery.

Current update and trend of 3D printing in spinal surgery: A bibliometric analysis and review of literature

Incorporation of three-dimensional (3D) printing technology into the field of spinal surgery is on the rise. A bibliometric analysis of the current topic was carried out to elaborate the trend and to navigate future research. A Scopus database search was conducted with keywords related to 3D printing, spine, and surgery. The final 792 articles were extracted and further analyzed with VOSviewer 1.6.19 and Biblioshiny. The first published article was in 2002. A notable increase in articles in 2014 might be attributable to the availability of cheaper 3D printers which rose significantly on a global scale in 2011. China leads in terms of published research on 3D printing in spinal surgery, followed by the US, Australia, and India. The author's keyword co-occurrence analysis reveals 8 theme clusters, including preoperative and intraoperative measures, biomodelling, spinal neoplasms, biomechanics of 3D-printed materials, degenerative spinal diseases, minimally invasive surgery, and bioprinting. The top 15 of the most recently cited keywords are listed to provide future researchers to produce impactful articles. Two strategic diagrams of 2 periods (2002-2018 and 2018-2023) show the theme's evolution. We found 6 consistent themes in keyword co-occurrence analysis and the strategic diagram analysis, that are promising subjects for future research. Overall, this bibliographic study indicates the expanding importance of 3D printing in spinal surgery and suggests several critical themes and impactful keywords for future researchers.