Standard navigation versus intraoperative computed tomography navigation in upper cervical spine trauma

A systematic review and meta-analysis of radiation exposure in spinal surgeries: Comparing C-Arm, CT navigation, and O-Arm techniques

INTRODUCTION

Advanced imaging techniques, such as C-arm fluoroscopy, O-arm, and CT navigation, are integral to achieving precision in orthopedic surgeries. However, these technologies also expose patients, surgeons, and operating room staff to varying levels of radiation. This systematic review and meta-analysis evaluate the radiation exposure (RE) associated with these imaging modalities and their impact on surgical outcomes.

METHODS

A comprehensive literature search was conducted following PRISMA guidelines, resulting in 2,725 identified articles. After removing duplicates and screening for eligibility, 24 studies were included in the analysis. Radiation exposure data, measured in milliSieverts (mSv) and milliGray (mGy), were standardized using conversion formulas. Quality assessments were performed using the Newcastle-Ottawa Scale (NOS) and ROB2 tools. Statistical analysis was conducted using random-effects models for comparing radiation exposure and fixed-effects models for secondary outcomes.

RESULTS

The meta-analysis included 11 studies: 8 studies comparing C-arm and CT navigation, and 3 studies comparing C-arm and O-arm technologies. The analysis revealed that CT navigation is associated with significantly higher RE compared to C-arm (Standardized Mean Difference (SMD): 4.73, 95% Confidence Interval (CI): 2.44 to 7.03; p < 0.0001). In contrast, there was no significant difference in RE between O-arm and C-arm (SMD: 1.34, 95% CI: -0.17 to 2.85; p = 0.082). Secondary analyses showed no significant differences in surgery duration or hospitalization length between CT navigation and C-arm techniques.

DISCUSSION

The results of this meta-analysis underscore the trade-offs between radiation exposure and surgical precision. While CT navigation significantly increases RE compared to C-arm fluoroscopy, it offers superior accuracy, particularly in critical precision surgeries such as spinal interventions. The lack of significant difference in RE between O-arm and C-arm technologies suggests that O-arm may provide a balanced approach, offering enhanced accuracy with radiation levels similar to C-arm. However, the significant heterogeneity among studies and inconsistent reporting of secondary outcomes indicate the need for further research. Future studies should focus on refining imaging techniques to optimize the balance between radiation safety and surgical accuracy.

CONCLUSION

C-arm imaging generally results in lower radiation exposure compared to CT navigation, making it preferable for standard procedures where extreme precision is not as critical. However, CT navigation's superior accuracy justifies its use in precision surgeries despite the higher radiation exposure. O-arm technology, with its comparable RE to C-arm and enhanced accuracy, represents a beneficial option where available. Ongoing research should aim to optimize imaging techniques, balancing the need for radiation safety with the demands for surgical precision.

Optimizing Single-Position Prone Lateral Lumbar Interbody Fusion with Exoscopic Technology: A Review of Key Innovations

Minimally invasive spine surgery has advanced significantly over the past decade, integrating technologies such as intraoperative navigation, robotics, and artificial intelligence with innovative techniques such as single-position prone lateral transpsoas lumbar interbody fusion (proLIF). While proLIF offers excellent clinical outcomes for a wide range of lumbar pathologies, the lateral approach to lumbar spine presents technical and ergonomic challenges, including an increased need for soft-tissue dissection and unfavorable ergonomics for surgeons. This review details how the combination of emerging technologies has been applied in minimally invasive lumbar spine surgery. It also describes the novel application of an exoscope during navigation-guided proLIF. The benefits offered by the exoscope included high-resolution, three-dimensional visualization, enhanced maneuverability, and improved surgeon ergonomics. By combining emerging technologies with novel surgical approaches, this review demonstrates the recent advancements in minimally invasive spine surgery and underscores the exoscope's potential to enhance visualization and optimize ergonomics for surgeons.

Comparison of iCT-based navigation and fluoroscopic-guidance for atlantoaxial screw placement in 78 patients with traumatic cervical spine injuries

BACKGROUND CONTEXT

Studies have shown biomechanical superiority of cervical pedicle screw placement over other techniques. However, accurate placement is challenging due to the inherent risk of neurovascular complications. Navigation technology based on intraoperative 3D imaging allows highly accurate screw placement, yet studies specifically investigating screw placement in patients with traumatic atlantoaxial injuries are scarce. The aim of this study was to compare atlantoaxial screw placement as treatment of traumatic instabilities using iCT-based navigation or fluoroscopic-guidance with intraoperative 3D control scans.

METHODS

This was a retrospective review of patients with traumatic atlantoaxial injuries treated operatively with dorsal stabilization of C1 and C2. Patients were either assigned to the intraoperative navigation or fluoroscopic-guidance group. Screw accuracy, procedure time, and revisions were compared.

RESULTS

Seventy-eight patients were included in this study with 51 patients in the navigation group and 27 patients in the fluoroscopic-guidance group. In total, 312 screws were placed in C1 and C2. Screw accuracy was high in both groups; however, pedicle perforations > 1 mm occurred significantly more often in the fluoroscopic-guidance group (P = 0.02). Procedure time was on average 23 min shorter in the navigation group (P = 0.02).

CONCLUSIONS

This study contributes to the available data showing that navigated atlantoaxial screw placement proves to be feasible as well as highly accurate compared to the fluoroscopic-guidance technique without prolonging the time needed for surgery. When comparing these data with other studies, the application of different classification systems for assessment of screw accuracy should be considered.

Accurate Placement and Revisions for Cervical Pedicle Screws Placed With or Without Navigation: A Systematic Review and Meta-Analysis

STUDY DESIGN

Systematic review and meta-analysis.

OBJECTIVES

To evaluate the accuracy of placement for cervical pedicle screws with and without the use of spinal navigation.

METHODS

A structured search was conducted in electronic databases without any language or date restrictions. Eligible studies reported the proportion of accurately placed cervical pedicle screws measured on intraoperative or postoperative 3D imaging, and reported whether intraoperative navigation was used during screw placement. Randomized Studies (MINORS) criteria were used to evaluate the methodological quality of how accuracy was assessed for cervical pedicle screws.

RESULTS

After screening and critical appraisal, 4697 cervical pedicle screws from 18 studies were included in the meta-analysis. The pooled proportion for cervical pedicle screws with a breach up to 2 mm was 94% for navigated screws and did not differ from the pooled proportion for non-navigated screws (96%). The pooled proportion for cervical pedicle screws placed completely in the pedicle was 76% for navigated screws and did not differ from the pooled proportion for non-navigated screws (82%). Intraoperative screw reposition rates and screw revision rates as a result of postoperative imaging also did not differ between navigated and non-navigated screw placement.

CONCLUSIONS

This systematic review and meta-analysis found that the use of spinal navigation systems does not significantly improve the accuracy of placement of cervical pedicle screws compared to screws placed without navigation. Future studies evaluating intraoperative navigation for cervical pedicle screw placement should focus on the learning curve, postoperative complications, and the complexity of surgical cases.

Comparison of radiation exposure and surgery time between an intraoperative CT with automatic surface registration and a preoperative CT with manual surface registration in navigated spinal surgeries

PURPOSE

This retrospective matched case-control study was conducted to compare two CT based surgery techniques for navigated screw placement in spinal surgery, whether a reduction of radiation exposure and surgery time could be achieved.

METHODS

We matched cases treated with an intraoperative CT (iCT), regarding the type and number of implants, with cases treated with a preoperative CT (pCT) of one main surgeon. Outcome measures were radiation exposure due to intraoperative control x-rays, radiation exposure due to CT images, and the duration of surgery.

RESULTS

The required radiation exposure could be significantly reduced in the iCT group. For the intraoperative control X-rays by 69% (median (MED) 88.50/standard deviation (SD) 107.84 and MED 286.00/SD 485.04 for iCT and pCT respectively-in Gycm²; p < 0.001) and for the CT examinations by 25% (MED 317.00/SD 158.62 and MED 424.50/SD 225.04 for iCT and pCT respectively-in mGycm; p < 0.001) with no significant change in surgery time. The correlation between the number of segments fused and the necessary surgery time decreased significantly for the iCT group (Pearson product-moment-correlation: r = 0.569 and r = 0.804 for iCT and pCT respectively; p < 0.05).

CONCLUSION

The results show that spinal navigation using an intraoperative CT with automatic registration compared to a preoperative CT and intraoperative manual surface registration, allows a significant reduction of radiation exposure, without prolonged surgery time. A significant benefit regarding cut-to-suture-time can be gained with surgeries of a larger scale.

Initial Intraoperative Experience with Robotic-Assisted Pedicle Screw Placement with Cirq® Robotic Alignment: An Evaluation of the First 70 Screws

BACKGROUND

Robot-guided spine surgery is based on a preoperatively planned trajectory that is reproduced in the operating room by the robotic device. This study presents our initial experience with thoracolumbar pedicle screw placement using Brainlab's Cirq^® surgeon-controlled robotic arm (BrainLab, Munich, Germany).

METHODS

All patients who underwent robotic-assisted implantation of pedicle screws in the thoracolumbar spine were included in the study. Our workflow, consisting of preoperative imagining, screw planning, intraoperative imaging with automatic registration, fusion of the preoperative and intraoperative imaging with a review of the preplanned screw trajectories, robotic-assisted insertion of K-wires, followed by a fluoroscopy-assisted insertion of pedicle screws and control iCT scan, is described.

RESULTS

A total of 12 patients (5 male and 7 females, mean age 67.4 years) underwent 13 surgeries using the Cirq^® Robotic Alignment Module for thoracolumbar pedicle screw implantation. Spondylodiscitis, metastases, osteoporotic fracture, and spinal canal stenosis were detected. A total of 70 screws were implanted. The mean time per screw was 08:27 ± 06:54 min. The mean time per screw for the first 7 surgeries (first 36 screws) was 16:03 ± 09:32 min and for the latter 6 surgeries (34 screws) the mean time per screw was 04:35 ± 02:11 min (p < 0.05). Mean entry point deviation was 1.9 ± 1.23 mm, mean deviation from the tip of the screw was 2.61 ± 1.6 mm and mean angular deviation was 3.5° ± 2°. For screw-placement accuracy we used the CT-based Gertzbein and Robbins System (GRS). Of the total screws, 65 screws were GRS A screws (92.85%), one screw was a GRS B screw, and two further screws were grade C. Two screws were D screws (2.85%) and underwent intraoperative revision. There were no perioperative deficits.

CONCLUSION

Brainlab's Cirq^® Robotic Alignment surgeon-controlled robotic arm is a safe and beneficial method for accurate thoracolumbar pedicle screw placement with high accuracy.

Navigation for surgical treatment of disorders of the cervical spine - A systematic review

INTRODUCTION

Computer-assisted navigation (CAN) is a well-established tool in spinal instrumentation surgery. Different techniques - each with specific advantages and disadvantages - are used in the cervical spine.

METHODS

A structured summary of different spinal navigation techniques and a review of the literature were done to discuss the advantages and disadvantages of specific navigation tools in the cervical spine.

RESULTS

In cervical spine surgery, CAN increases the accuracy of pedicle screw placement, reduces screw mispositioning and leads to fewer revision surgeries. Due to the mobility of the cervical spine, preoperative CT followed by region matching or intraoperative CT are recommended.

CONCLUSIONS

CAN increases pedicle screw placement accuracy and should be used in spinal instrumentation for the cervical spine whenever possible.

Accuracy and safety of C2 pedicle or pars screw placement: a systematic review and meta-analysis

STUDY DESIGN

Systematic review and meta-analysis.

AIM

The purpose of this study was to compare the safety and accuracy of the C2 pedicle versus C2 pars screws placement and free-hand technique versus navigation for upper cervical fusion patients.

METHODS

Databases searched included PubMed, Scopus, Web of Science, and Cochrane Library to identify all papers published up to April 2020 that have evaluated C2 pedicle/pars screws placement accuracy. Two authors individually screened the literature according to the inclusion and exclusion criteria. The accuracy rates associated with C2 pedicle/pars were extracted. The pooled accuracy rate estimated was performed by the CMA software. A funnel plot based on accuracy rate estimate was used to evaluate publication bias.

RESULTS

From 1123 potentially relevant studies, 142 full-text publications were screened. We analyzed data from 79 studies involving 4431 patients with 6026 C2 pedicle or pars screw placement. We used the Newcastle-Ottawa Scale (NOS) to evaluate the quality of studies included in this review. Overall, funnel plot and Begg's test did not indicate obvious publication bias. The pooled analysis reveals that the accuracy rates were 93.8% for C2 pedicle screw free-hand, 93.7% for pars screw free-hand, 92.2% for navigated C2 pedicle screw, and 86.2% for navigated C2 pars screw (all, P value < 0.001). No statistically significant differences were observed between the accuracy of placement C2 pedicle versus C2 pars screws with the free-hand technique and the free-hand C2 pedicle group versus the navigated C2 pedicle group (all, P value > 0.05).

CONCLUSION

Overall, there was no difference in the safety and accuracy between the free-hand and navigated techniques. Further well-conducted studies with detailed stratification are needed to complement our findings.

Reliable navigation registration in cranial and spine surgery based on intraoperative computed tomography

OBJECTIVE

Low registration errors are an important prerequisite for reliable navigation, independent of its use in cranial or spinal surgery. Regardless of whether navigation is used for trajectory alignment in biopsy or implant procedures, or for sophisticated augmented reality applications, all depend on a correct registration of patient space and image space. In contrast to fiducial, landmark, or surface matching–based registration, the application of intraoperative imaging allows user-independent automatic patient registration, which is less error prone. The authors’ aim in this paper was to give an overview of their experience using intraoperative CT (iCT) scanning for automatic registration with a focus on registration accuracy and radiation exposure.

METHODS

A total of 645 patients underwent iCT scanning with a 32-slice movable CT scanner in combination with navigation for trajectory alignment in biopsy and implantation procedures (n = 222) and for augmented reality (n = 437) in cranial and spine procedures (347 craniotomies and 42 transsphenoidal, 56 frameless stereotactic, 59 frame-based stereotactic, and 141 spinal procedures). The target registration error was measured using skin fiducials that were not part of the registration procedure. The effective dose was calculated by multiplying the dose length product with conversion factors.

RESULTS

Among all 1281 iCT scans obtained, 1172 were used for automatic patient registration (645 initial registration scans and 527 repeat iCT scans). The overall mean target registration error was 0.86 ± 0.38 mm (± SD) (craniotomy, 0.88 ± 0.39 mm; transsphenoidal, 0.92 ± 0.39 mm; frameless, 0.74 ± 0.39 mm; frame-based, 0.84 ± 0.34 mm; and spinal, 0.80 ± 0.28 mm). Compared with standard diagnostic scans, a distinct reduction of the effective dose could be achieved using low-dose protocols for the initial registration scan with mean effective doses of 0.06 ± 0.04 mSv for cranial, 0.50 ± 0.09 mSv for cervical, 4.12 ± 2.13 mSv for thoracic, and 3.37 ± 0.93 mSv for lumbar scans without impeding registration accuracy.

CONCLUSIONS

Reliable automatic patient registration can be achieved using iCT scanning. Low-dose protocols ensured a low radiation exposure for the patient. Low-dose scanning had no negative effect on navigation accuracy.