O-arm navigation versus C-arm guidance for pedicle screw placement in spine surgery: a systematic review and meta-analysis

Computer tomography-assisted 3-dimensional navigation in spine surgery: a narrative review on safety, accuracy, efficacy and reduction of complications

The computed tomography-assisted 3D navigation system is a useful tool for spinal surgeons, enabling them to enhance the effectiveness and safety of surgical procedures by providing real-time three-dimensional information during decompression, resection, and instrumentation. Specific advantages of this navigation system include precise pedicle screw placement, the capability for immediate intraoperative correction, and execution of minimally invasive surgeries with reduced radiation exposure for the surgical team. Noteworthy disadvantages of this system are the relatively high implementation costs, the need for specific training, and limited accessibility to outpatient surgery centers. Currently, spinal navigation systems are constantly being upgraded with additional innovations, such as integration with robotics and improvement of the existing tools, which will ultimately lead to a better quality of life for patients and an improved experience for surgeons.

Advancements and Challenges in Computer-Assisted Navigation for Cervical Spine Surgery: A Comprehensive Review of Perioperative Integration, Complications, and Emerging Technologies

Study DesignA narrative review of the current literature on the application of Computer-Assisted Navigation (CAN) in cervical spine surgeries.ObjectiveTo analyze the perioperative integration, types of CAN systems, technical considerations, and clinical applications of CAN in cervical spine surgeries, as well as to assess the associated complications and potential strategies to minimize these risks.MethodsA comprehensive review of published studies between 2015 and 2024 was conducted to evaluate the usage, benefits, and challenges of CAN in cervical spine surgeries. The review covered perioperative integration, system types, complications, and emerging technologies, including augmented reality (AR) and robotics.ResultsThe use of CAN in cervical spine surgeries provides improved accuracy in screw placement and reduced neurovascular complications. However, the review identified several limitations, such as a steep learning curve, cost considerations, and potential inaccuracies related to cervical spine mobility.ConclusionsCAN offers significant benefits in cervical spine surgeries, including enhanced precision and reduced complications. Despite the current limitations, advancements in AR and robotics hold promise for improving the safety and effectiveness of CAN in cervical procedures. The future focus should be on overcoming the existing challenges to increase the adoption of CAN in cervical spine surgeries.

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.

Variations of Radiographic Parameters Relevant to the Presumed Lower Instrumented Vertebrae During Intraoperative Fluoroscopic Positioning for Lenke 5/6 Adolescent Idiopathic Scoliosis

BACKGROUND

Radiographic evaluation of the presumed lower instrumented vertebrae (LIV) is crucial for determining the optimal fusion level for adolescent idiopathic scoliosis (AIS) with main thoracolumbar/lumbar curves. However, few studies have examined its variations intraoperatively. This study aims to investigate the radiographic variations of the presumed LIV during fluoroscopic positioning to aid surgeons in decision-making.

METHODS

Lenke 5/6 AIS patients who underwent correction surgery in our center were consecutively recruited from January 2021 to December 2023. The spinal radiographs, including preoperative standing X-ray, recumbent computed tomography (CT), and intraoperative positioning fluoroscopy, were collected. The parameters of the presumed LIV were measured and compared. The correlation analysis was also performed to establish the liner regression equation.

RESULTS

Ninety-seven patients, comprising 23 boys and 74 girls, were enrolled, with an average main curve of 55.1 ± 11.0°. The vertebral body tilt and disc angle of the presumed LIV were 27.2 ± 6.2° and 8.5 ± 3.8° on preoperative standing X-rays, respectively, both significantly decreasing on CT images and intraoperative fluoroscopy. The rotation of the presumed LIV also showed significant differences intraoperatively. Significant correlations were observed between vertebral body tilt and disc angle across X-rays, CT images, and fluoroscopy. A linear equation was established for predicting intraoperative variations of the presumed LIV based on baseline X-rays.

CONCLUSIONS

This study firstly reports the radiographic variations of the presumed LIV using intraoperative positioning fluoroscopy for Lenke 5/6 AIS and establishes the correlation with baseline measurements. This information may assist surgeons in selecting the optimal LIV, but long-term follow-up is needed to evaluate its outcomes.

Current state and future perspectives of spinal navigation and robotics-an AO spine survey

Introduction

The use of robotics in spine surgery has gained popularity. This study aims to assess the current state of robotics and raise awareness of its educational implications.

Research question

What are the current adoption trends and barriers to the implementation of robotic assistance in spine surgery?

Material and methods

An online questionnaire comprising 27 questions was distributed to AO spine members between October 25th and November 13th, 2023, using the SurveyMonkey platform (https://www.surveymonkey.com; SurveyMonkey Inc., San Mateo, CA, USA). Statistical analyses (descriptive statistics, Pearson Chi-Square tests) and generation of all graphs were performed using SPSS Version 29.0.1.0 (IBM SPSS Statistic).

Results

We received 424 responses from AO Spine members (response rate = 9.9 %). The participants were mostly board-certified orthopedic surgeons (46 %, n = 195) and neurosurgeons (32%, n = 136). While 49% (n = 208) of the participants reported occasional or frequent use of navigation assistance, only 18 % (n = 70) indicated the use of robotic assistance for spinal instrumentation. A significant difference based on the country's median income status (p < 0.001) and the respondent's number of annual instrumentation procedures (p < 0.001) has been observed. While 11 % (n = 47) of all surgeons use a spinal robot frequently, 36 % (n = 153) of the participants stated they don't need a robot from a current perspective. Most participants (77%, n = 301) concluded that high acquisition costs are the primary barrier for the implementation of robotics.

Discussion and conclusion

Although the hype for robotics in spine surgery increased recently, robotic systems remain non-standard equipment due to cost constraints and limited usability.

Evaluation of a compact cone beam CT concept with high image fidelity for point-of-care brain imaging

Cone beam computed tomography (CBCT) has potential advantages for developing portable, cost-effective point-of-care CT systems for intracranial imaging, such as early stroke diagnosis, hemorrhage detection, and intraoperative navigation. However, large volume imaging with flat panel detector based CBCT significantly increases the scattered radiation fluence which reduces its image quality and utility. To address these issues, a compact CBCT concept with enhanced image quality was investigated for intracranial imaging. The new system features a novel antiscatter collimator and data correction method to address the challenges in imaging large volumes with CBCT. A benchtop CBCT prototype was constructed. Imaging studies with anthropomorphic phantoms showed that soft tissue visualization, Hounsfield Unit (HU) accuracy, contrast, and spatial resolution increased significantly with the proposed CBCT concept, and they were comparable to the values measured in the gold standard multidetector-row CT (MDCT) images. Contrast-to-noise ratio (CNR) in CBCT images was within 12-31% of the CNR in MDCT images. These findings indicate that a compact CBCT system integrated with effective scatter suppression techniques may have increased utility in the context of brain imaging, and the proposed approach may enable the development of point-of-care CT systems for head imaging based on flat panel detector based CBCT technology.

Higher Accuracy and Better Clinical Outcomes in Navigated Thoraco-Lumbar Pedicle Screw Fixation Versus Conventional Techniques : A Systematic Review and Meta-Analysis

STUDY DESIGN

A systematic review and meta-analysis.

OBJECTIVE

This study aims to compare pedicle screw accuracy, clinical outcomes, and complications between navigated and conventional techniques.

SUMMARY OF BACKGROUND DATA

In the last decades, intraoperative navigation has been introduced in spinal surgery to prevent risks and complications.

MATERIALS AND METHODS

The search was executed on Cochrane Central Library, PubMed, and Scopus on April 30, 2023. Randomized controlled trials, prospective and retrospective studies that compared pedicle screw accuracy in the thoracic-lumbar-sacral segments, blood loss, operative time, hospital stay, intraoperative and postoperative revision of screws, neurological and systemic complications, Visual Analogue Scale (VAS), and Oswestry Disability Index (ODI) between navigated and freehand or fluoroscopy-assisted techniques were included in this study. The meta-analysis was performed using Review Manager software. Clinical outcomes were assessed as continuous outcomes with mean difference, while pedicle screw accuracy and complications were assessed as dichotomous outcomes with odds ratio, all with 95% CIs. The statistical significance of the results was fixed at P <0.05.

RESULTS

This meta-analysis included 30 studies for a total of 17,911 patients and 24,600 pedicle screws. Statistically significant results in favor of the navigated technique were observed for the accuracy of pedicle screws ( P =0.0001), hospital stay ( P =0.0002), blood loss ( P <0.0001), postoperative revision of pedicle screws ( P <0.00001), and systemic complications ( P =0.0008). In particular, the positioning of the screws was clinically acceptable in 96.2% of the navigated group and 94.2% with traditional techniques. No significant differences were found in VAS, ODI, and operative time between the two groups.

CONCLUSION

Navigated pedicle screw fixation has been demonstrated to be a safe and effective technique with high improvement in clinical outcomes and accuracy in patients undergoing spinal fusion compared with conventional techniques.

LEVEL OF EVIDENCE

Level III.

A comparison of ultrasound volume navigation, O-arm navigation, and X-ray guidance for screw placement in minimally invasive transforaminal lumbar interbody fusion: a randomized controlled trial

OBJECTIVE

To compare the differences between Ultrasound Volume Navigation (UVN), O-arm Navigation, and conventional X-ray fluoroscopy-guided screw placement in Minimally Invasive Transforaminal Lumbar Interbody Fusion (MIS-TLIF) surgeries.

METHODS

A total of 90 patients who underwent MIS-TLIF due to lumbar disc herniation from January 2022 to January 2023 were randomly assigned to the UVN group, O-arm group, and X-ray group. UVN, O-arm navigation, and X-ray guidance were used for screw placement in the respective groups, while the remaining surgical procedures followed routine MIS-TLIF protocols. Intraoperative data including average single screw placement time, total radiation dose, and average effective radiation dose per screw were recorded and calculated. On the 10th day after surgery, postoperative X-ray and CT examinations were conducted to assess screw placement accuracy and facet joint violation.

RESULTS

There were no significant differences in general characteristics among the three groups, ensuring comparability. Firstly, the average single screw placement time in the O-arm group was significantly shorter than that in the UVN group and X-ray group (P<0.05). Secondly, in terms of total radiation dose during surgery, for single-level MIS-TLIF, the O-arm group had a significantly higher radiation dose compared to the UVN group and X-ray group (P<0.05). However, for multi-level MIS-TLIF, the X-ray group had a significantly higher radiation dose than the O-arm group and UVN group (P<0.05). In terms of average single screw radiation dose, the O-arm group and X-ray group were similar (P>0.05), while the UVN group was significantly lower than the other two groups (P<0.05). Furthermore, no significant differences were found in screw placement assessment grades among the three groups (P>0.05). However, in terms of facet joint violation rate, the UVN group (10.3%) and O-arm group (10.7%) showed no significant difference (P>0.05), while the X-ray group (26.7%) was significantly higher than both groups (P<0.05). Moreover, in the UVN group, there were significant correlations between average single screw placement time and placement grade with BMI index (r = 0.637, P<0.05; r = 0.504, P<0.05), while no similar significant correlations were found in the O-arm and X-ray groups.

CONCLUSION

UVN-guided screw placement in MIS-TLIF surgeries demonstrates comparable efficiency, visualization, and accuracy to O-arm navigation, while significantly reducing radiation exposure compared to both O-arm navigation and X-ray guidance. However, UVN may be influenced by factors like obesity, limiting its application.

Accurate placement of thoracolumbar pedicle screws using a handheld iOS-based navigation device: a prospective intra-patient agreement study

BACKGROUND

Accurate pedicle screw placement is a challenge with reported misplacement rates of 10% and higher. A handheld navigation device (HND) may provide accuracy equal to CT-based navigation (CT-Nav) but without the cost and complexity.

OBJECTIVE

To study the accuracy of a handheld navigation device for pedicle screw placement.

STUDY DESIGN

This prospective cross-sectional study with consistently applied reference standard enrolled 20 patients undergoing 92 pedicle screw placements.

PATIENTS

Patients who underwent pedicle screw placement between May 2022 and September 2022.

OUTCOME MEASURES

Pedicle screw placement accuracy per Gertzbein-Robbins.

METHODS

Once the screw pilot hole was established, the proposed trajectory of the HND was compared with that proposed by CT-Nav. Postoperatively, screw accuracy was graded according to Gertzbein-Robbins by a blinded radiologist based on CT scans. Accuracy was compared between the two systems and published control for fluoroscopy assisted and CT-Nav placement using Bayesian posterior distribution.

RESULTS

The trajectory proposed by the HND and CT-Nav were in agreement in 98.9% (95% Exact CI; 94.09%-99.97%). The HND accuracy was 98.9% with 91 screws rated "A" and 1 rated "C". Noninferiority to fluoroscopic placement was achieved because the one-sided normal-approximation 95% CI Lower Bound (LB) of 95.3% is greater than the Performance Goal (PG) of 83.4%. Posthoc analysis demonstrated that the probability of superiority of the HND relative to the historical accuracy rate of 91.5% for fluoroscopy assisted procedures is >0.999 and that the HND's accuracy rate is within 4.5% of CT-Nav of 95.5% is >0.999. No adverse events or intra-operative complications associated with HND were observed. There was 1 (1.1%) intra-operative repositioning and no reoperations for any reason.

CONCLUSIONS

The accuracy rate of the HND was 98.9%, and the proposed trajectory matched with CT-Nav in 98.9% of the time. This is superior to the historical published accuracy rate for fluoroscopy-assisted procedures and equivalent to the historical published accuracy rate for CT-Nav.

CLINICAL TRIAL REGISTRATION NUMBER

Dutch trial register NL74268.058.20.

How I do it. Posterolateral lumbar spine fixation and decompression with navigation interfaced with a robotic exoscope with head mounted display

INTRODUCTION

Lumbar spine fixation and fusion is currently performed with intraoperative tools such as intraoperative CT scan integrated to navigation system to provide accurate and safe positioning of the screws. The use of microscopic visualization systems enhances visualization and accuracy during decompression of the spinal canal as well.

METHODS

We introduce a novel setting in microsurgical decompression and fusion of lumbar spine using an exoscope with robotized arm (RoboticScope) interfaced with navigation and head mounted displays.

CONCLUSION

Spinal canal decompression and fusion can effectively be performed with RoboticScope, with significant advantages especially regarding ergonomics.

Unlocking Precision in Spinal Surgery: Evaluating the Impact of Neuronavigation Systems

OBJECTIVE

In spine surgery, ensuring the safety of vital structures is crucial, and various instruments contribute to the surgeon's confidence. This study aims to present outcomes from spinal cases operated on using the freehand technique and neuronavigation with an O-arm in our clinic. Additionally, we investigate the impact of surgical experience on outcomes by comparing early and late cases operated on with neuronavigation.

METHOD

We conducted a retrospective analysis of spinal patients operated on with the freehand technique and neuronavigation in our clinic between 2019 and 2020, with a minimum follow-up of 2 years. Cases operated on with neuronavigation using the O-arm were categorized into early and late groups.

RESULTS

This study included 193 patients, with 110 undergoing the freehand technique and 83 operated on utilizing O-arm navigation. The first 40 cases with neuronavigation formed the early group, and the subsequent 43 cases comprised the late group. The mean clinical follow-up was 29.7 months. In the O-arm/navigation group, 796 (99%) of 805 pedicle screws were in an acceptable position, while the freehand group had 999 (89.5%) of 1117 pedicle screws without damage. This rate was 98% in the early neuronavigation group and 99.5% in the late neuronavigation group.

CONCLUSIONS

The use of O-arm/navigation facilitates overcoming anatomical difficulties, leading to significant reductions in screw malposition and complication rates. Furthermore, increased experience correlates with decreased surgical failure rates.

Accuracy and Safety of Freehand Placement of Upper Thoracic Pedicle Screws Supported Solely by Anteroposterior, i.e., Frontal, X-Ray Fluoroscopy (C-Arm): Technical Note Including 23 Patients

BACKGROUND

Biomechanical resistance and surgical morbidity of spinal posterior pedicle screw fixation depend on the intraosseous position of the implants. Upper thoracic pedicle screws are particularly demanding given their convergence and thin character. We present our experience as military surgeons of freehand placement of upper thoracic pedicle screws supported solely by anteroposterior, i.e., frontal x-ray fluoroscopy.

METHODS

A single-center retrospective analysis was performed at Sainte-Anne Military Teaching Hospital between 2017 and 2024 of patients in whom upper thoracic pedicle screw (T1-T5) were placed with anteroposterior fluoroscopy guidance only.

RESULTS

Analysis included 23 patients (mean age 59; male/female ratio 3.6; 16 traumatic lesions and 7 neoplastic lesions) in whom 15 cervicothoracic junction fixation and 8 upper thoracic spine surgeries were performed. Of 124 screws inserted (T1-T5), 85% (106/124) were graded 0 (Gertzbein-Robbins scale), whereas 14.5% (18/124) displayed some degree of misplacement (grades 1-3). All T1 screws (22/22) were accurately placed compared with 83% (20/24) of T2 screws, 88% (30/34) of T3 screws, 85% (17/20) of T4 screws, and 71% (17/24) of T5 screws, with no clinical complications. There were 3 surgical revisions (1 asymptomatic misplaced screw, 2 mechanical failures in trauma). Finally, 92.7% (51/55) of the screws inserted during working hours were accurately placed compared with 79.7% (55/69) inserted during after-hours surgeries (P = 0.039).

CONCLUSIONS

Clinically, placement of upper thoracic pedicle screws supported solely by anteroposterior fluoroscopy appears to be safe. The surgical technique is simple enough to be used in settings with limited resources, such as a mobile field surgical team.

Automated measurement of lumbar pedicle screw parameters using deep learning algorithm on preoperative CT scans

Purpose

This study aims to devise and assess an automated measurement framework for lumbar pedicle screw parameters leveraging preoperative computed tomography (CT) scans and a deep learning algorithm.

Methods

A deep learning model was constructed employing a dataset comprising 1410 axial preoperative CT images of lumbar pedicles sourced from 282 patients. The model was trained to predict several screw parameters, including the axial angle and width of pedicles, the length of pedicle screw paths, and the interpedicular distance. The mean values of these parameters, as determined by two radiologists and one spinal surgeon, served as the reference standard.

Results

The deep learning model achieved high agreement with the reference standard for the axial angle of the left pedicle (ICC = 0.92) and right pedicle (ICC = 0.93), as well as for the length of the left pedicle screw path (ICC = 0.82) and right pedicle (ICC = 0.87). Similarly, high agreement was observed for pedicle width (left ICC = 0.97, right ICC = 0.98) and interpedicular distance (ICC = 0.91). Overall, the model's performance paralleled that of manual determination of lumbar pedicle screw parameters.

Conclusion

The developed deep learning-based model demonstrates proficiency in accurately identifying landmarks on preoperative CT scans and autonomously generating parameters relevant to lumbar pedicle screw placement. These findings suggest its potential to offer efficient and precise measurements for clinical applications.

Deep Learning-Based Localization and Orientation Estimation of Pedicle Screws in Spinal Fusion Surgery

Objective

This study investigated the application of a deep learning-based object detection model for accurate localization and orientation estimation of spinal fixation surgical instruments during surgery.

Methods

We employed the You Only Look Once (YOLO) object detection framework with oriented bounding boxes (OBBs) to address the challenge of non-axis-aligned instruments in surgical scenes. The initial dataset of 100 images was created using brochure and website images from 11 manufacturers of commercially available pedicle screws used in spinal fusion surgeries, and data augmentation was used to expand 300 images. The model was trained, validated, and tested using 70%, 20%, and 10% of the images of lumbar pedicle screws, with the training process running for 100 epochs.

Results

The model testing results showed that it could detect the locations of the pedicle screws in the surgical scene as well as their direction angles through the OBBs. The F1 score of the model was 0.86 (precision: 1.00, recall: 0.80) at each confidence level and mAP50. The high precision suggests that the model effectively identifies true positive instrument detections, although the recall indicates a slight limitation in capturing all instruments present. This approach offers advantages over traditional object detection in bounding boxes for tasks where object orientation is crucial, and our findings suggest the potential of YOLOv8 OBB models in real-world surgical applications such as instrument tracking and surgical navigation.

Conclusion

Future work will explore incorporating additional data and the potential of hyperparameter optimization to improve overall model performance.

Combined vertebroplasty and pedicle screw insertion for vertebral consolidation: feasibility and technical considerations

PURPOSE

To assess the feasibility and technical accuracy of performing pedicular screw placement combined with vertebroplasty in the radiological setting.

METHODS

Patients who underwent combined vertebroplasty and pedicle screw insertion under combined computed tomography and fluoroscopic guidance in 4 interventional radiology centers from 2018 to 2023 were retrospectively assessed. Patient demographics, vertebral lesion type, and procedural data were analyzed. Strict intra-pedicular screw positioning was considered as technical success. Pain score was assessed according to the Visual Analogue Scale before the procedure and in the 1-month follow-up consultation.

RESULTS

Fifty-seven patients (38 men and 19 women) with a mean age of 72.8 (SD = 11.4) years underwent a vertebroplasty associated with pedicular screw insertion for the treatment of traumatic fractures (29 patients) and neoplastic disease (28 patients). Screw placement accuracy assessed by post-procedure CT scan was 95.7% (89/93 inserted screws). A total of 93 pedicle screw placements (36 bi-pedicular and 21 unipedicular) in 32 lumbar, 22 thoracic, and 3 cervical levels were analyzed. Mean reported procedure time was 48.8 (SD = 14.7) min and average injected cement volume was 4.4 (SD = 0.9) mL. A mean VAS score decrease of 5 points was observed at 1-month follow-up (7.7, SD = 1.3 versus 2.7, SD = 1.7), p < .001.

CONCLUSION

Combining a vertebroplasty and pedicle screw insertion is technically viable in the radiological setting, with a high screw positioning accuracy of 95.7%.

Clinical Application and Curative Effect Analysis of Postural Awareness Surgical Tool Assisted Nail Placement in Adolescent Idiopathic Scoliosis

OBJECTIVE

The pedicle screw technique has been widely used in adolescent idiopathic scoliosis orthopedic surgery, but misplacement of screws may damage important structures such as blood vessels and nerves around the pedicle, resulting in serious consequences. Therefore, our research team has independently developed a surgical tool to assist in the placement of pedicle screws. This study aims to investigate the safety and accuracy of postural awareness tool assisted nail placement in orthopedic surgery for adolescent idiopathic scoliosis.

METHOD

A retrospective analysis was performed on 24 adolescent patients with idiopathic scoliosis admitted to our hospital from July 2019 to July 2022, including 10 males and 14 females, with an average age of 14.88 ± 2.36 years (10-19 years). The mean follow-up was 15.67 ± 2.20 months (12-20 months). We divided the patients into postural awareness group (n = 12) and C-arm group (n = 12) according to whether the postural awareness surgical tool was used during the operation. All patients were treated with posterior spinal orthopedic surgery. The postural awareness group was assisted by pedicle screw placement with a postural awareness surgical tool, while the C-arm group was given a pedicle screw placement with freehand technique. The operative time, intraoperative blood loss, intraoperative fluoroscopy times, nail placement related complications, nail placement accuracy, and scoliosis correction rate were recorded and compared between the two groups.

RESULTS

The operative time, intraoperative blood loss and fluoroscopy times in the postural awareness group were significantly lower than those in the C-arm group, with statistical significance (p < 0.05). The postural awareness group implanted 163 screws with an accuracy rate of 91.41%, while the C-arm group implanted 159 screws with an accuracy rate of 83.02%. The accuracy rate of screw placement in the postural awareness group was higher than that in the C-arm group, with a statistically significant difference (p = 0.024). According to the imaging of the patients, there was no significant difference between the Cobb Angle of the main bend measured at three time points before surgery, 1 week after surgery and the last follow-up between the two groups. Similarly, there was no significant difference in the rate of lateral curvature correction between the two groups.

CONCLUSION

The application of postural awareness surgical tool in posterior orthopedic surgery for adolescent idiopathic scoliosis can improve screw placement accuracy, shorten screw placement time, and make auxiliary screw placement safer and more accurate.

Navigated pedicle screw insertion with the Surgivisio system: Malposition rate and risk factors - about 648 screws

PURPOSE

Pedicle screw malposition rates vary greatly in scientific literature depending on the chosen criteria. Different techniques have been developed to lower the risk of screw malposition. Our primary objective is to evaluate the malposition rate associated with the use of the Surgivisio navigation system and to identify risk factors for screw malposition. The secondary objectives are to assess operating time and radiation data.

MATERIALS AND METHODS

We performed a monocentric retrospective consecutive case series. All patients operated for pedicle screw implantation using the Surgivisio system between September 2017 and June 2020 were included. Screw positioning was evaluated on postoperative CT scans using Heary and Gertzbein classifications. Thirteen potential risk factors for screw malposition were hypothesized and tested with a univariate and multivariate analysis.

RESULTS

Six hundred and forty-eight screws could be evaluated in 97 patients. Our study reported a 92.4% satisfactory screw implantation rate with a mean operative time per screw of 14.5±6.7minutes and a patient effective dose of 0.47±0.31 mSv per screw. One screw was neurotoxic and required an early revision (0.15%). Three risk factors for screw malposition have been identified in a multivariate analysis: female gender (OR=2.13 [1.11; 4], p=0.0219), an implantation level above D10 (OR=2.17 [1.13; 4.16], p=0.0197), and an "open" surgery (as opposed to percutaneous) (OR=3.47 [1.83; 6.56], p=0.0002).

CONCLUSION

Pedicle screw malposition rate and operative time with the Surgivisio navigation system are comparable with those reported in scientific literature. We theorized that intraoperative patient reference displacement could be a major cause of navigation failure.

LEVEL OF EVIDENCE

IV.

A Novel Intraoperative CT Navigation System for Spinal Fusion Surgery in Lumbar Degenerative Disease: Accuracy and Safety of Pedicle Screw Placement

Background: In recent years, intraoperative computed tomography (CT) navigation has become widely used for the insertion of pedicle screws in spinal fusion surgery. However, conventional intraoperative CT navigation may be impaired by infrared interference between the infrared camera and surgical instruments, which can lead to the misplacement of pedicle screws. Recently, a novel intraoperative CT navigation system, NextAR, has been developed. It uses a small infrared camera mounted on surgical instruments within the surgical field. NextAR navigation can minimize the problem of infrared interference and be expected to improve the accuracy of pedicle screw placement. Methods: This study investigated the accuracy of pedicle screw insertion under NextAR navigation in spinal fusion surgery for lumbar degenerative diseases. The accuracy of pedicle screw placement was evaluated in 15 consecutive patients using a CT grading scale. Results: Screw perforation occurred in only 1 of the total 70 screws (1.4%). Specifically, there was one grade 1 perforation within 2 mm, but no perforations larger than 2 mm. There were no reoperations or neurological complications due to screw misplacement. Conclusions: NextAR navigation can provide high accuracy for pedicle screw insertion and help ensure safe spinal fusion surgery for lumbar degenerative diseases.

Innovations in Spine Surgery: A Narrative Review of Current Integrative Technologies

Neurosurgical technologies have become increasingly more adaptive, featuring real-time and patient-specific guidance in preoperative, intraoperative, and postoperative settings. This review offers insight into how these integrative innovations compare with conventional approaches in spine surgery, focusing on machine learning (ML), artificial intelligence, augmented reality and virtual reality, and spinal navigation systems. Data on technology applications, diagnostic and procedural accuracy, intraoperative times, radiation exposures, postoperative outcomes, and costs were extracted and compared with conventional methods to assess their advantages and limitations. Preoperatively, augmented reality and virtual reality have applications in surgical training and planning that are more immersive, case specific, and risk-free and have been shown to enhance accuracy and reduce complications. ML algorithms have demonstrated high accuracy in predicting surgical candidacy (up to 92.1%) and tailoring personalized treatments based on patient-specific variables. Intraoperatively, advantages include more accurate pedicle screw insertion (96%-99% with ML), enhanced visualization, reduced radiation exposure (49 μSv with O-arm navigation vs. 556 μSv with fluoroscopy), increased efficiency, and potential for fewer intraoperative complications compared with conventional approaches. Postoperatively, certain ML and artificial intelligence models have outperformed conventional methods in predicting all postoperative complications of >6000 patients as well as predicting variables contributing to in-hospital and 90-day mortality. However, applying these technologies comes with limitations, such as longer operative times (up to 35.6% longer) with navigation, dependency on datasets, costs, accessibility, steep learning curve, and inherent software malfunctions. As these technologies advance, continuing to assess their efficacy and limitations will be crucial to their successful integration within spine surgery.

Mixed Reality-Based Navigation for Pedicle Screw Placement: A Preliminary Study Using a 3D-Printed Spine Model

Background and objectives Mixed reality (MR) is one of the image processing technologies that allows the user to manipulate three-dimensional (3D) virtual images (hologram). The aim of this study was to evaluate the accuracy of MR-based pedicle screw (PS) placement using 3D spine models. Materials and methods Using the preoperative CT data of a patient with adolescent idiopathic scoliosis (AIS) who had undergone posterior spinal fusion in our hospital, a 3D-printed spine model was created. On the other hand, a 3D hologram of the same patient was automatically created using the preoperative CT data uploaded to the Holoeyes MD service website (Holoeyes Inc., Tokyo, Japan). Using a Magic Leap One® headset (Magic Leap Inc., Plantation, FL), the 3D hologram with lines of predetermined PS trajectories was superimposed onto the 3D-printed spine model and PS were inserted bilaterally along with the trajectory lines from T5 to L3. As a control, we used a readymade 3D spine model of AIS and inserted PS bilaterally with a freehand technique from T4 to L3. The rate of pedicle violation was compared between the MR-based and freehand techniques. Results A total of 22 and 24 PS were placed into the 3D-printed spine model of our patient and the readymade 3D spine model, respectively. The rate of pedicle violation was 4.5% (1/22 screws) in the MR-based technique and 29.2% (7/24 screws) in the freehand technique (P = 0.049). Conclusions We demonstrated a significantly lower rate of PS misplacement in the MR-based technique than in the freehand technique. Therefore, an MR-assisted system is a promising tool for PS placement in terms of feasibility, safety, and accuracy, warranting further studies including cadaveric and clinical studies.

Navigation-Assisted One-Staged Posterior Spinal Fusion Using Pedicle Screw Instrumentation in Adolescent Idiopathic Scoliosis-A Case Series

Background and Objectives: Adolescent idiopathic scoliosis (AIS) is a prevalent three-dimensional spinal disorder, with a multifactorial pathogenesis, including genetics and environmental aspects. Treatment options include non-surgical and surgical treatment. Surgical interventions demonstrate positive outcomes in terms of deformity correction, pain relief, and improvements of the cardiac and pulmonary function. Surgical complications, including excessive blood loss and neurologic deficits, are reported in 2.27-12% of cases. Navigation-assisted techniques, such as the O-arm system, have been a recent focus with enhanced precision. This study aims to evaluate the results and complications of one-stage posterior instrumentation fusion in AIS patients assisted by O-arm navigation. Materials and Methods: This retrospective study assesses 55 patients with AIS (12-28 years) who underwent one-stage posterior instrumentation correction supported by O-arm navigation from June 2016 to August 2023. We examined radiological surgical outcomes (initial correction rate, loss of correction rate, last follow-up correction rate) and complications as major outcomes. The characteristics of the patients, intraoperative blood loss, operation time, number of fusion levels, and screw density were documented. Results: Of 73 patients, 55 met the inclusion criteria. The average age was 16.67 years, with a predominance of females (78.2%). The surgical outcomes demonstrated substantial initial correction (58.88%) and sustained positive radiological impact at the last follow-up (56.56%). Perioperative complications, including major and minor, occurred in 18.18% of the cases. Two patients experienced a major complication. Blood loss (509.46 mL) and operation time (402.13 min) were comparable to the literature ranges. Trend analysis indicated improvements in operation time and blood loss over the study period. Conclusions: O-arm navigation-assisted one-stage posterior instrumentation proves reliable for AIS corrective surgery, achieving significant and sustained positive radiological outcomes, lower correction loss, reduced intraoperative blood loss, and absence of implant-related complications. Despite the challenges, our study demonstrates the efficacy and maturation of this surgical approach.

Assessing Procedural Accuracy in Lateral Spine Surgery: A Retrospective Analysis of Percutaneous Pedicle Screw Placement with Intraoperative CT Navigation

Percutaneous pedicle screws (PPSs) are commonly used in posterior spinal fusion to treat spine conditions such as trauma, tumors, and degenerative diseases. Precise PPS placement is essential in preventing neurological complications and improving patient outcomes. Recent studies have suggested that intraoperative computed tomography (CT) navigation can reduce the dependence on extensive surgical expertise for achieving accurate PPS placement. However, more comprehensive documentation is needed regarding the procedural accuracy of lateral spine surgery (LSS). In this retrospective study, we investigated patients who underwent posterior instrumentation with PPSs in the thoracic to lumbar spine, utilizing an intraoperative CT navigation system, between April 2019 and September 2023. The system's methodology involved real-time CT-based guidance during PPS placement, ensuring precision. Our study included 170 patients (151 undergoing LLIF procedures and 19 trauma patients), resulting in 836 PPS placements. The overall PPS deviation rate, assessed using the Ravi scale, was 2.5%, with a notably higher incidence of deviations observed in the thoracic spine (7.4%) compared to the lumbar spine (1.9%). Interestingly, we found no statistically significant difference in screw deviation rates between upside and downside PPS placements. Regarding perioperative complications, three patients experienced issues related to intraoperative CT navigation. The observed higher rate of inaccuracies in the thoracic spine suggests that various factors may contribute to these differences in accuracy, including screw size and anatomical variations. Further research is required to refine PPS insertion techniques, particularly in the context of LSS. In conclusion, this retrospective study sheds light on the challenges associated with achieving precise PPS placement in the lateral decubitus position, with a significantly higher deviation rate observed in the thoracic spine compared to the lumbar spine. This study emphasizes the need for ongoing research to improve PPS insertion techniques, leading to enhanced patient outcomes in spine surgery.

Learning curve across 2000 thoracolumbar pedicle screw placements using O-arm navigation: technical difficulties and their solutions

INTRODUCTION

Instrumentation using the intraoperative O-arm navigation technique appears safer than its predecessor techniques. However, only a handful of surgeons often used navigation during spinal surgeries. Too many operative glitches and unreliable navigation accuracy were the important reasons cited even by experienced surgeons for not using spinal navigation. We have studied the accuracy of pedicle screw placement during the learning curve and beyond it. We have also discussed in detail the intricacies of the technique and solutions to the difficulties encountered using spinal navigation.

MATERIALS AND METHODS

A total of 2000 thoracolumbar pedicle screws have been placed in the 324 spine surgeries meeting the inclusion and exclusion criteria included in this retrospective study. We have divided 2000 pedicle screw placements into consecutive groups of 200 each. We have compared these groups for the accuracy of screw placement with the surgeon's experience.

RESULTS

The accuracy of pedicle screw placement using the "in-versus-out" grading system in group 1 was 85.5% which significantly increased in group 2 to 93.5% (p-value: 0.0099), and thereafter, there was a nonsignificant increase in subsequent groups with the graph achieving the shape of a plateau.

CONCLUSION

Surgeons should learn the correct principles of the technique of O-arm navigation to prevent the loss of accuracy and place pedicle screws with high accuracy. There is a learning curve of around 30-35 surgeries or 200 pedicle screw placements to acclimatize with the technique of O-arm navigation and learn its principles.

Image-to-Patient Registration in Computer-Assisted Surgery of Head and Neck: State-of-the-Art, Perspectives, and Challenges

Today, image-guided systems play a significant role in improving the outcome of diagnostic and therapeutic interventions. They provide crucial anatomical information during the procedure to decrease the size and the extent of the approach, to reduce intraoperative complications, and to increase accuracy, repeatability, and safety. Image-to-patient registration is the first step in image-guided procedures. It establishes a correspondence between the patient's preoperative imaging and the intraoperative data. When it comes to the head-and-neck region, the presence of many sensitive structures such as the central nervous system or the neurosensory organs requires a millimetric precision. This review allows evaluating the characteristics and the performances of different registration methods in the head-and-neck region used in the operation room from the perspectives of accuracy, invasiveness, and processing times. Our work led to the conclusion that invasive marker-based methods are still considered as the gold standard of image-to-patient registration. The surface-based methods are recommended for faster procedures and applied on the surface tissues especially around the eyes. In the near future, computer vision technology is expected to enhance these systems by reducing human errors and cognitive load in the operating room.

Navigated Dorsal Root Ganglion Stimulation (DRGS) for the Treatment of Chronic Refractory Coccygodynia: A Case Report

Sacral stimulation is a well-established therapy for urologic neuromodulation. After the advent of dorsal root ganglion (DRG) stimulation, pain surgeons have started to reach this target mostly for pelvic and sacral pain. For those without good surgical experience, sacral foramen puncture, especially S3 and S4, can be a challenge, due to its entry angle and limited C-arm image resolution. In this report, we describe a new technique to utilize sacral navigation using the O-arm approach to guide DRG stimulation implants. We discuss a case of a 53-year-old male patient with refractory coccygodynia, who underwent sacral DRG implantation using neuronavigation. Punctures could be done without the need for multiple attempts to reach the foramen in this patient.

Postoperative computed tomography imaging of pediatric patients with craniosynostosis: radiation dose and image quality comparison between multi-slice computed tomography and O-arm cone-beam computed tomography

BACKGROUND

When postoperative multi-slice computed tomography (MSCT) imaging of patients with craniosynostosis is used, it is usually performed a few days after surgery in a radiology department. This requires additional anesthesia for the patient. Recently, intraoperative mobile cone-beam CT (CBCT) devices have gained popularity for orthopedic and neurosurgical procedures, which allows postoperative CT imaging in the operating room.

OBJECTIVE

This single-center retrospective study compared radiation dose and image quality of postoperative imaging performed using conventional MSCT scanners and O-arm CBCT.

MATERIALS AND METHODS

A total of 104 pediatric syndromic and non-syndromic patients who were operated on because of single- or multiple-suture craniosynostosis were included in this study. The mean volumetric CT dose index (CTDIvol) and dose-length product (DLP) values of optimized craniosynostosis CT examinations (58 MSCT and 46 CBCT) were compared. Two surgeons evaluated the subjective image quality.

RESULTS

CBCT resulted in significantly lower CTDIvol (up to 14%) and DLP (up to 33%) compared to MSCT. Multi-slice CT image quality was considered superior to CBCT scans. However, all scans were considered to be of sufficient quality for diagnosis.

CONCLUSION

The O-arm device allowed for an immediate postoperative CBCT examination in the operating theater using the same anesthesia induction. Radiation exposure was lower in CBCT compared to MSCT scans, thus further encouraging the use of O-arms. Cone-beam CT imaging with an O-arm is a feasible method for postoperative craniosynostosis imaging, yielding less anesthesia to patients, lower health costs and the possibility to immediately evaluate results of the surgical operation.

A Prospective Cohort Study of Radiation Exposure to a Spine Surgeon's Exposed Body Parts During Utilization of Intraoperative Radiation-based Imaging

STUDY DESIGN

Prospective cohort study.

SUMMARY OF BACKGROUND DATA

C-arm fluoroscopy and O-arm navigation are vital tools in modern spine surgeries, but their repeated usage can endanger spine surgeons. Although a surgeon's chest and abdomen are protected by lead aprons, the eyes and extremities generally receive less protection.

OBJECTIVE

In this study, we compare differences in intraoperative radiation exposure across the protected and unprotected regions of a surgeon's body.

METHODS

Sixty-five consecutive spine surgeries were performed by a single spine-focused neurosurgeon over 9 months. Radiation exposure to the primary surgeon was measured through dosimeters worn over the lead apron, under the lead apron, on surgical loupes, and as a ring on the dominant hand. Differences were assessed with rigorous statistical testing and radiation exposure per surgical case was extrapolated.

RESULTS

During the study, the measured radiation exposure over the apron, 176 mrem, was significantly greater than that under the apron, 8 mrem (P = 0.0020), demonstrating a shielding protective effect. The surgeon's dominant hand was exposed to 329 mrem whereas the eyes were exposed to 152.5 mrem of radiation. Compared with the surgeon's protected abdominal area, the hands (P = 0.0002) and eyes (P = 0.0002) received significantly greater exposure. Calculated exposure per case was 2.8 mrem for the eyes and 5.1 mrem for the hands. It was determined that a spine-focused neurosurgeon operating 400 cases annually will incur a radiation exposure of 60,750 mrem to the hands and 33,900 mrem to the eyes over a 30-year career.

CONCLUSIONS

Our study found that spine surgeons encounter significantly more radiation exposure to the eyes and the extremities compared with protected body regions. Lifetime exposure exceeds the annual limits set by the International Commission on Radiologic Protection for the extremities (50,000 mrem/y) and the eyes (15,000 mrem/y), calling for increased awareness about the dangerous levels of radiation exposure that a spine surgeon incurs over one's career.

O-Arm- and Guide-Device-Assisted Personalized Percutaneous Kyphoplasty for Thoracolumbar Osteoporotic Vertebral Compression Fractures

With the ageing of the global population, the incidence of osteoporotic vertebral compression fractures (OVCFs) is increasing. To assess the safety and efficacy of O-arm- and guide-device-assisted personalized percutaneous kyphoplasty (PKP) for treating thoracolumbar OVCFs, a total of 38 consecutive thoracolumbar OVCF patients who underwent bilateral PKP assisted with an O-arm and a guide device (O-GD group, n = 16) or traditional fluoroscopy (TF group, n = 22) from January 2020 to December 2021 were retrospectively reviewed, and their epidemiologic, clinical and radiological outcomes were analysed. The operation time was significantly decreased (p < 0.001) in the O-GD group (38.3 ± 12.2 min) compared with the TF group (57.2 ± 9.7 min). The number of intraoperative fluoroscopy exposures was significantly decreased (p < 0.001) in the O-GD group (31.9 ± 4.5) compared with the TF group (46.7 ± 7.2). Intraoperative blood loss was significantly decreased (p = 0.031) in the O-GD group (6.9 ± 2.5 mL) compared with the TF group (9.1 ± 3.3 mL). No significant difference (p = 0.854) in the volume of injected cement was observed between the O-GD group (6.8 ± 1.3 mL) and the TF group (6.7 ± 1.7 mL). Both the clinical and radiological outcomes, including the visual analogue scale score for pain, Oswestry Disability Index and anterior height and local kyphotic angle of the fractured vertebrae, were significantly improved at the postoperative and final follow-up but did not differ between the two groups. The incidence of cement leakage and refracture of the vertebral body was similar in the two groups (p = 0.272; p = 0.871). Our preliminary study demonstrated that O-GD-assisted PKP is a safe and effective procedure that presents a significantly shorter operation time, fewer intraoperative fluoroscopy exposures and less intraoperative blood loss than the TF technique.

[Application of navigation in the fractured spine]

OBJECTIVE

Computer navigation is used in patients with spine fractures to optimize the accuracy of pedicle screws and thereby reduce intra- and postoperative complications, such as injuries to vessels, nerves and accompanying structures. In addition, the ideal screw length and diameter for each pedicle can be detected to ensure optimal stability.

INDICATIONS

Intraoperative navigation is suitable for the treatment of spine fractures, which require dorsal stabilization or fusion. It is primarily used for dorsal procedures ranging from the cervical to lumbar/sacral spine.

CONTRAINDICATIONS

Computer navigation relies on rigid fixation of the dynamic reference base (DRB) at the spinous process. Failure of DRB fixation is the major contraindication for navigation in the spine.

SURGICAL TECHNIQUE

After acquisition of an intraoperative three-dimensional (3D) scan, a digital relation between the anatomy and the 3D scan is established with the navigation system and its infrared camera. Pedicle screws are planned percutaneously with a calibrated pointer. In the next step K‑wires (or screws) are implanted after the pedicles are drilled with a calibrated drill guide. After implantation, an additional 3D scan is performed to verify accurate K‑wire placement.

POSTOPERATIVE MANAGEMENT

Postoperative management does not differ compared to nonnavigated procedures.

RESULTS

Intraoperative navigation in combination with modern imaging systems leads to very high accuracy for pedicle screws. Immediate intraoperative control of K‑wires as well as screws and fracture reduction can avoid revision surgery. Image guidance can reduce radiation exposure for the surgical team.

Bone conductivity and spine fluoroscopy, Hand-Eye-Ear dialogue, during pedicle screw positioning: a new human cognitive system for precision and radiation-decrease; better than artificial intelligence and machine learning system?

PURPOSE

There is an increasing need for pedicle screw positioning while decreasing radiation exposure. This study compares intra-operative radiation dose using posterior internal fixation using impedancemetry-guided pedicle positioning by the Pediguard system versus standard free-hand sighting when surgery was performed with a trainee or expert surgeon.

MATERIAL AND METHODS

Using the electrical properties of bone, the Pediguard detects iatrogenic penetration of the pedicle wall and gives auditory feedback to the surgeon. A single centre, two surgeons (one experienced and the other novice) conducted a continuous prospective randomized study for one year. Twenty patients were randomized into one group (free-hand control group) receiving pedicle instrumentation without the use of the Pediguard and the second group receiving pedicle instrumentation with the use of the Pediguard. The total screw placement times and fluoroscopic times for each screw was recorded and pedicle screw position was analyzed on post-operative CT scan.

RESULTS

Among the 104 screwed pedicles, 22 unrecognized perforations were detected by CT scan, while no perforation signal was observed intra-operatively. Only one perforation was greater than 2 mm. The overall screwing time was 4.33 ± 1.2 minutes per screw for experienced surgeon and 5.84 ± 2.5 minutes per screw for the novice. Pediguard did not increased significantly the time (0.3 mn per screw) for the experienced surgeon, but the time with Pediguard was longer (2 mn more per screw) for the novice surgeon, particularly at the thoracic level. The overall fluoroscopic average time per screw for the experienced surgeon is 5.8 ± 2.3 s and 10.4 ± 4.5 s for the novice surgeon. For the novice surgeon, radiation time reduced from 12 (without Pediguard) to 6 s (with Pediguard). There was no significant difference for the experienced surgeon in terms of improvement in radiation time with the use of Pediguard.

CONCLUSION

The overall time was longer for the novice surgeon with the Pediguard system, but allowed to decrease by 50% the fluoroscopy time.

Comparison of pedicle screw fixation by four different posterior approaches for the treatment of type A thoracolumbar fractures without neurologic injury

Purpose

This study was designed to compare the pedicle screw fixation by four different posterior approaches for the treatment of type A thoracolumbar fractures without neurologic injury.

Methods

A total of 165 patients with type A thoracolumbar fractures without neurologic injury who received pedicle screw fixation by posterior approaches from February 2017 to August 2018 were enrolled in this study. They were further divided into the following four groups according to different posterior approaches: Open-C group (conventional open approach), Open-W group (Wiltse approach), MIS-F group (percutaneous approach with fluoroscopy guidance), and MIS-O group (percutaneous approach with O-arm navigation). The demographic data, clinical outcomes, and radiologic parameters were evaluated and compared among the four groups.

Results

There were no significant differences in age, gender, fracture segment, and follow-up time. The incision length, blood loss, hospital stay time, and VAS (Visual Analog Scale) and ODI (Oswestry Disability Index) scores at the early stage of post-operation were the worst in the Open-C group. The MIS-O group showed significantly higher accuracy rate of pedicle position than other groups. The preoperative and postoperative AVH (anterior vertebral height) and VWA (vertebral wedge angle) obtain obvious correction in all patients immediately after and 1 year post-operation. No difference was found among the four groups at the final radiographic follow-up.

Conclusions

The four different posterior approaches are effective in treating type A thoracolumbar fractures in our study. Each approach has its own individual strengths and weaknesses and therefore requires comprehensive consideration prior to use. Proper approaches selection is critical to patients.

Pedicle Screw Placement Aided by C-Arm Fluoroscopy: A "Nevermore without" Technology to Pursue Optimal Spine Fixation

The surgical technique and the intraoperative technology that support spinal pedicle screw placement have consistently evolved over the past decades to decrease the misplacement rate of pedicle screws. We retrospectively evaluated our case series by analyzing the period 2016-2020. Patients undergoing pedicle screw fixation for cervical, thoracic, or lumbar spine degenerative diseases have been included. Surgery was carried out with the aid of intraoperative 3D C-arm fluoroscopy to assess and optimize screw placement and/or correct possible mispositioning. Each patient underwent a postoperative CT scan. Our aim was to evaluate the safety and accuracy of pedicle screw placement and estimate the variation in mispositioning rates. We carried out 329 surgical procedures, as follows: 70 cervical, 78 thoracic spine, and 181 lumbar spine surgeries. An excellent overall pedicle screw positioning was obtained, with slight differences between the cervical (98.6%), thoracic (100%), and lumbar (98.9%) tracts. Accordingly, only three patients required a revision surgery owing to mispositioning (0.91%). In particular, intraoperative C-arm fluoroscopy significatively improved the accuracy of thoracic screw positioning, as shown by postoperative CT scans. Our experience proves the crucial role of intraoperative C-arm fluoroscopy in pursuing optimal technical results and improving patient outcomes at follow-up.

Single-Position Oblique Lumbar Interbody Fusion and Percutaneous Pedicle Screw Fixation under O-Arm Navigation: A Retrospective Comparative Study

The insertion of pedicle screws in the lateral position without a position change has been reported. We completed a retrospective comparison of the radiologic and clinical outcomes of 36 patients who underwent either single-position oblique lateral lumbar interbody fusion (SP-OLIF) using the O-arm (36 cases) or conventional OLIF (C-OLIF) using the C-arm (20 cases) for L2-5 single-level lumbar degenerative diseases. Radiological parameters were analyzed, including screw accuracy (Gertzbein-Robbins classification system; GRS), segmental instability, and fusion status. Screw misplacement was defined as a discrepancy of ≥2 mm. Clinical outcomes, including visual analog scale, Oswestry Disability Index (ODI), 36-Item Short Form Health Survey (SF-36), and postoperative complications, were assessed. The spinal fusion rate was not different between the SP-OLIF and C-OLIF groups one year after surgery (p = 0.536). The ODI score was lower (p = 0.015) in the SP-OLIF than the C-OLIF group. Physical (p = 0.000) and mental component summaries (p = 0.000) of the SF-36 were significantly higher in the SP-OLIF group. Overall complication rates, including revision, surgical site infection, ipsilateral weakness, and radicular pain/numbness, were not significantly different. SP-OLIF using the O-arm procedure is feasible, with acceptable accuracy, fusion rate, and complication rate. This may be an alternative to conventional two-stage operations.

The design and application of an individualized 3D printing assisted guide plates in assisting sacroiliac screws insertion

OBJECTIVE

Currently, the sacroiliac screws insertion still faces several challenges in the fixation of pelvic and acetabular injuries. This study was aimed to design a personalized three-dimensional (3D) printing assisted guide plates to assist sacroiliac screws insertion, so as to provide a reference for further clinical applications.

METHODS

Eight pelvic specimens (5 males and 3 females) of normal adults were used to simulate actual operation. After thin-layer CT scanning, the 3D models of pelvis were established based on the images data. Furthermore, in Mimics 17.0 software, the screw entry points and screw channels of sacroiliac screws were further simulated and designed, and the appropriate range of the posterior superior iliac spine was selected to establish and print the virtual guide plates. Then, the simulated screws insertion was performed in vitro, the pelvic specimens after screws insertion were scanned again by CT, and the effect of screws insertion was further evaluated.

RESULTS

A total of 16 sacroiliac screw guide plates were designed and printed, and 48 screws were inserted on both sides. Therein, 45 screws were completely located in the sacral vertebra, which was determined as grade 0, with an accuracy rate of 93.2%. The other 3 screws penetrated the anterior cortex or sacral canal of sacral vertebra, including 2 screws in Grade 1 (4.1%) and 1 screw in Grade 2 (2.1%). Compared with the simulated screw channels, the anterior and posterior offset angles of the cross section were (0.912 ± 0.625) ° and (0.802 ± 0.681) ° respectively, with no significant difference (p > 0.05). The upper and lower offset angles of coronal plane were (1.158 ± 0.823) ° and (1.034 ± 0.908) ° respectively, and there was no significant difference (p > 0.05).

CONCLUSIONS

3 D printing guide plates assisted sacroiliac screws insertion can enhance the stability of pelvic posterior ring fixation and assist surgeons to reduce the difficulty of operation.

SAP Principle Guided Free Hand Technique: A Secret for T1 to S1 Pedicle Screw Placement

OBJECTIVE

Existing freehand techniques of screw placement mainly emphasized on various entry points and complex trajectory reference. The aim of this study is to illustrate a standardized and reliable freehand technique of pedicle screw insertion for open pedicle screw fixation with a universal entry point and a stereoscopic trajectory reference system and report the results from a single surgeon's clinical experience with the technique.

METHOD

In this study, the author respectively reviewed a total of 200 consecutive patients who had undergone open freehand pedicle screw fixation with Superior Articular Process (SAP) technique from January 2019 to May 2020. For accuracy and safety, all 200 cases had undergone postoperative X-ray while 33 cases including spinal deformity, infection, and tumor had received additional CT-scan. Screw accuracy was analyzed via a CT-based classification system with Student's t test.

RESULTS

A total of 1126 screws had been placed from T1-S1 with SAP-guided freehand technique and the majority had been confirmed safe in X-ray without the need of CT scan. A total of 316 screws in deformity or infectious or tumor cases had undergone additional CT scan with 95.5% (189 of 198 screws) accuracy in thoracic group and 94.9% (112 of 118 screws) in lumbar group. The accuracy had been 90.5% (114 of 126 screws) in deformity group and 95.8% (182 of 190 screws) in non-deformity group. All perforation cases had been rated Grade B (<2 mm) without significant difference between the medial and the lateral (p < 0.05). No cases had been detected with significant neurological deficiencies. The mean intraoperative X-ray shots were 0.73 per screw.

CONCLUSION

SAP-guidance is a reliable freehand technique for thoracic and lumbar pedicle screw instrument. It allows accurate and safe screw insertion in both non-deformity and deformity cases with less radiation exposure.

CT-Navigated Spinal Instrumentations-Three-Dimensional Evaluation of Screw Placement Accuracy in Relation to a Screw Trajectory Plan

Background and Objectives: In the literature, spinal navigation and robot-assisted surgery improved screw placement accuracy, but the majority of studies only qualitatively report on screw positioning within the vertebra. We sought to evaluate screw placement accuracy in relation to a preoperative trajectory plan by three-dimensional quantification to elucidate technical benefits of navigation for lumbar pedicle screws. Materials and Methods: In 27 CT-navigated instrumentations for degenerative disease, a dedicated intraoperative 3D-trajectory plan was created for all screws. Final screw positions were defined on postoperative CT. Trajectory plans and final screw positions were co-registered and quantitatively compared computing minimal absolute differences (MAD) of screw head and tip points (mm) and screw axis (degree) in 3D-space, respectively. Differences were evaluated with consideration of the navigation target registration error. Clinical acceptability of screws was evaluated using the Gertzbein−Robbins (GR) classification. Results: Data included 140 screws covering levels L1-S1. While screw placement was clinically acceptable in all cases (GR grade A and B in 112 (80%) and 28 (20%) cases, respectively), implanted screws showed considerable deviation compared to the trajectory plan: Mean axis deviation was 6.3° ± 3.6°, screw head and tip points showed mean MAD of 5.2 ± 2.4 mm and 5.5 ± 2.7 mm, respectively. Deviations significantly exceeded the mean navigation registration error of 0.87 ± 0.22 mm (p < 0.001). Conclusions: Screw placement was clinically acceptable in all screws after navigated placement but nevertheless, considerable deviation in implanted screws was noted compared to the initial trajectory plan. Our data provides a 3D-quantitative benchmark for screw accuracy achievable by CT-navigation in routine spine surgery and suggests a framework for objective comparison of screw outcome after navigated or robot-assisted procedures. Factors contributing to screw deviations should be considered to assure optimal surgical results when applying navigation for spinal instrumentation.

Navigation Techniques in Endoscopic Spine Surgery

Endoscopic spine surgery (ESS) advances the principles of minimally invasive surgery, including minor collateral tissue damage, reduced blood loss, and faster recovery times. ESS allows for direct access to the spine through small incisions and direct visualization of spinal pathology via an endoscope. While this technique has many applications, there is a steep learning curve when adopting ESS into a surgeon's practice. Two types of navigation, optical and electromagnetic, may allow for widespread utilization of ESS by engendering improved orientation to surgical anatomy and reduced complication rates. The present review discusses these two available navigation technologies and their application in endoscopic procedures by providing case examples. Furthermore, we report on the future directions of navigation within the discipline of ESS.

Intraoperative 3D Imaging Reduces Pedicle Screw Related Complications and Reoperations in Adolescents Undergoing Posterior Spinal Fusion for Idiopathic Scoliosis: A Retrospective Study

Widely used surgical treatment for adolescent idiopathic scoliosis (AIS) is posterior spinal fusion using pedicle screw instrumentation (PSI). Two-dimensional (2D) or three-dimensional (3D) navigation is used to track the screw positioning during surgery. In this study, we evaluated the screw misplacement, complications, and need for reoperations of intraoperative 3D as compared to 2D imaging in AIS patients. There were 198 adolescents, of which 101 (51%) were evaluated with 2D imaging and 97 (49%) with 3D imaging. Outcome parameters included radiographic correction, health-related quality of life (HRQOL), complications, and reoperations. The mean age was 15.5 (SD 2.1) years at the time of the surgery. Forty-four (45%) patients in the 3D group and 13 (13%) patients in the 2D group had at least one pedicle screw repositioned in the index operation (p < 0.001). Six (6%) patients in the 2D group, and none in the 3D group had a neurological complication (p = 0.015). Five (5%) patients in the 2D group and none in the 3D group required reoperation (p = 0.009). There were no significant differences in HRQOL score at two-year follow-up between the groups. In conclusion, intraoperative 3D imaging reduced pedicle screw-related complications and reoperations in AIS patients undergoing PSI as compared with 2D imaging.

Comparison of pedicle screw placement accuracy between two types of imaging support (Artis Zeego versus two-dimensional fluoroscopy): a cross-sectional observational study

Background

The pedicle screw system is widely used in spine surgery, and it provides rigid fixation and leads to successful subsequent deformity correction and bony fusion. The standard imaging technique for pedicle screw insertion is two-dimensional images obtained from C-arm-type X-ray fluoroscopy. Artis Zeego is an emerging intraoperative imaging technique that can provide conventional two-dimensional fluoroscopic images and rapid three-dimensional fluoroscopic computed tomography reconstruction imaging. The aim of this study is to compare the insertion accuracies of PS placement using Artis Zeego and conventional 2D X-ray fluoroscopy.

Methods

In this study, we retrospectively reviewed the postoperative images of thoracolumbar fusion patients who underwent surgery using pedicle screws between 2013 and 2018. Pedicle screw malplacement was assessed using a four-grade classification by Rao et al. Misplacement rates were compared between pedicle screws assisted with Artis Zeego and two-dimensional fluoroscopy.

Results

A total of 1107 pedicle screws in 153 patients were inserted using Artis Zeego, and 427 pedicle screws in 80 patients were inserted using fluoroscopy. The overall perforation rate was 4.2% (46 perforations of 1106 pedicle screws) in the Artis Zeego group and 7.7% (33 perforations of 427 pedicle screws) in the fluoroscopy group. In the Artis Zeego group, 43 (3.9%) screws were classified as grade 1, and three (0.3%) screws were classified as grade 2. In the fluoroscopy group, 21 (4.9%) screws were classified as grade 1, 10 (2.3%) screws were classified as grade 2, and 2 (0.5%) screws were classified as grade 3. The use of Artis Zeego was associated with a significantly lower screw malplacement rate than was the use of fluoroscopy (p < 0.001).

Conclusions

Our results demonstrated that pedicle screw placement with Artis Zeego was associated with a lower malplacement rate than was conventional two-dimensional fluoroscopy. No severe malplacement was observed in the Artis Zeego group. Thus, Artis Zeego could be a good option for improving pedicle screw accuracy.

Does MIS-TLIF or TLIF result in better pedicle screw placement accuracy and clinical outcomes with navigation guidance?

Background

Although previous studies have suggested that navigation can improve the accuracy of pedicle screw placement, few studies have compared navigation-assisted transforaminal lumbar interbody fusion (TLIF) and navigation-assisted minimally invasive TLIF (MIS-TLIF). The entry point of pedicle screw insertion in navigation-assisted MIS-TLIF (NM-TLIF) may deviate from the planned entry point due to an uneven bone surface, which may result in misplacement. The purpose of this study was to explore the pedicle screw accuracy and clinical consequences of MIS-TLIF and TLIF, both under O-arm navigation, to determine which surgical method is better.

Methods

A retrospective study of 54 patients who underwent single-segment NM-TLIF or navigation-assisted TLIF (N-TLIF) was conducted. In addition to the patients’ demographic characteristics, intraoperative indicators and complications, the Oswestry Disability Index (ODI) and visual analog scale (VAS) score were recorded and analyzed preoperatively and at the 1-, 6-, and 12-month and final postoperative follow-ups. The clinical qualitative accuracy and absolute quantitative accuracy of pedicle screw placement were assessed by postoperative CT. Multifidus muscle injury was evaluated by T2-weighted MRI.

Results

Compared with N-TLIF, NM-TLIF was more advantageous in terms of the incision length, intraoperative blood loss, drainage volume, time to ambulation, length of hospital stay, blood transfusion rate and analgesia rate (P < 0.05). The ODI and VAS scores for low back pain were better than those of N-TLIF at 1 month and 6 months post-surgery (P < 0.05). There was no significant difference in the clinical qualitative screw placement accuracy (97.3% vs. 96.2%, P > 0.05). The absolute quantitative accuracy results showed that the axial translational error, sagittal translational error, and sagittal angle error in the NM-TLIF group were significantly greater than those in the N-TLIF group (P < 0.05). The mean T2-weighted signal intensity of the multifidus muscle in the NM-TLIF group was significantly lower than that in the N-TLIF group (P < 0.05).

Conclusions

Compared with N-TLIF, NM-TLIF has the advantages of being less invasive, yielding similar or better screw placement accuracy and achieving better symptom relief in the midterm postoperative recovery period. However, more attention should be given to real-time adjustment for pedicle insertion in NM-TLIF rather than just following the entry point and trajectory of the intraoperative plan.

Improved Accuracy and Safety of Pedicle Screw Placement by Using a Probe with an Electrical Conductivity-Measuring Device during Severe Syndromic and Neuromuscular Scoliosis Spine Surgery

An electrical conductivity-measuring device (ECD) has recently been developed to support pedicle screw placement. However, no evidence exists regarding its efficacy for syndromic/neuromuscular scoliosis with extremely difficult screwing. We retrospectively reviewed 2010-2016 medical records of 21 consecutive syndromic/neuromuscular scoliosis patients undergoing free-hand segmental fixation surgery at our institution and compared the pedicle screw insertion accuracy and safety between 10 with a conventional non-ECD probe (2010-2013) and 11 with an ECD probe (2014-2016). We analyzed preoperative pedicle shape and postoperative screw placement in computed tomography. There were no significant differences between ECD and non-ECD groups in demographic, clinical, and treatment characteristics including scoliosis severity and pedicle diameter. The abandonment rate due to liquorrhea or perforation was lower in ECD (12.3%) than in non-ECD (26.7%) (p < 0.01). Acceptable insertion without perforation or <2-mm lateral/cranial position was more frequent in ECD (67.1%) than in non-ECD (56.9%) (p = 0.02). Critical ≥5-mm medial/caudal malposition was not seen in ECD (0.0%) but in non-ECD (2.4%) (p = 0.02). The perforation distance was shorter in ECD (2.2 ± 1.1 mm) than in non-ECD (2.6 ± 1.7 mm) (p = 0.01). Results involve small sample size, selection, performance, and learning curve biases; nevertheless, ECD could be useful for more accurate and safer pedicle screw placement in severe syndromic/neuromuscular scoliosis.

O-Arm Assisted Cervicothoracic Spine Pedicle Screw Placement Accuracy Is Higher Than C-Arm Fluoroscopy

OBJECTIVE

We compared the accuracy of C-arm fluoroscopy versus O-arm-assisted pedicle screw (PS) placement in the cervicothoracic spinal junction (CTSJ).

METHODS

Patients who underwent PS placement in the CTSJ (C7-T4) at our hospital were included in this study. Of 37 patients who underwent PS placement in the CTSJ, 20 underwent intraoperative C-arm fluoroscopy-assisted surgery (C Group) and 17 underwent intraoperative O-arm-assisted surgery (O Group). In total, 159 PSs were placed-73 in the C Group and 86 in the O Group. The accuracy of PS placement was compared between the C Group and O Group using the classification proposed by Gertzbein and Robbins to analyze pedicle violation.

RESULTS

PS accuracy was higher in the O Group than C Group; PS placement evaluated as grade A, representing no perforation, was 95.3% (82/86) for the O Group, whereas it was 78.1% (57/73) for the C Group. There was a clear statistically significant difference in accuracy of PS placement between the groups (P = 0.0013).

CONCLUSIONS

O-arm-assisted surgery improved the accuracy of PS placement in the CTSJ.

Never events in orthopaedics: A nationwide data analysis and guidance on preventative measures

BACKGROUND

Never Events (NE) are serious clinical incidents that are wholly preventable if appropriate institutional safeguards are in place and followed. They are often used as a surrogate of the quality of healthcare delivered by an institution. Most NEs are surgical and orthopaedic surgery is one of the most involved specialties.

OBJECTIVE

The aim of this study was to identify common NE themes associated with orthopaedics within the National Health Service (NHS) of England.

METHOD

We conducted an observational study analysing the annual NE data published by the NHS England from 2012 to 2020 to collate all orthopaedic surgery-related NE and construct relevant recurring themes.

RESULTS

We identified 460 orthopaedic NE out of a total of 3247 (14.16%) reported NE to NHS England. There were 206 Wrong implants/prostheses under 8 different themes. Wrong hip and knee prosthesis were the commonest "wrong implants" (n = 94; 45.63% and n = 91; 44.17% respectively). There were 197 "Wrong-site surgery" incidents in 22 different themes. The commonest of these was the laterality problems accounting for 64 (32.48%) incidents followed by 63 (31.97%) incidents of wrong spinal level interventions. There were 18 (9.13%) incidents of intervention on the wrong patients and 17 (8.62%) wrong incisions. Retained pieces of instruments were the commonest retained foreign body with 15 (26.13%) incidents. The next categories were retained drill parts and retained instruments with 13 (22.80%) incidents each.

CONCLUSION

We identified 47 different themes of NE specific to orthopaedic surgery. Awareness of these themes would help in their prevention. Site marking can be challenging in the presence of cast and on operating on the digits and spine. Addition of a Real-time intra-operative implant scan to the National Joint Registry can avoid wrong implant selection while Fiducial markers, intraoperative imaging, O-arm navigation, and second time-out could help prevent wrong level spinal surgery.

Computer-assisted surgery and navigation in foot and ankle: state of the art and fields of application

Computer-assisted orthopaedic surgery (CAOS) is a real-time navigation guidance system that supports surgeons intraoperatively.Its use is reported to increase precision and facilitate less-invasive surgery.Advanced intraoperative imaging helps confirm that the initial aim of surgery has been achieved and allows for immediate adjustment when required.The complex anatomy of the foot and ankle, and the associated wide range of challenging procedures should benefit from the use of CAOS; however, reports on the topic are scarce.This article explores the fields of applications of real-time navigation and CAOS in foot and ankle surgery. Cite this article: EFORT Open Rev 2021;6:531-538. DOI: 10.1302/2058-5241.6.200024.

Neurologic Complications in Monitored versus Unmonitored Image-Guidance Assisted Posterior Lumbar Instrumentation

BACKGROUND

Intraoperative neurophysiologic monitoring (IOM) has been used clinically since the 1970s and is a reliable tool for detecting impending neurologic compromise. However, there are mixed data as to whether long-term neurologic outcomes are improved with its use. We investigated whether IOM used in conjunction with image guidance produces different patient outcomes than with image guidance alone.

METHODS

We reviewed 163 consecutive cases between January 2015 and December 2018 and compared patients undergoing posterior lumbar instrumentation with image guidance using and not using multimodal IOM. Monitored and unmonitored surgeries were performed by the same surgeons, ruling out variability in intersurgeon technique. Surgical and neurologic complication rates were compared between these 2 cohorts.

RESULTS

A total of 163 patients were selected (110 in the nonmonitored cohort vs. 53 in the IOM cohort). Nineteen signal changes were noted. Only 3 of the 19 patients with signal changes had associated neurologic deficits postoperatively (positive predictive value 15.7%). There were 5 neurologic deficits that were observed in the nonmonitored cohort and 8 deficits observed in the monitored cohort. Transient neurologic deficit was significantly higher in the monitored cohort per case (P < 0.0198) and per screw (P < 0.0238); however, there was no difference observed between the 2 cohorts when considering permanent neurologic morbidity per case (P < 0.441) and per screw (P < 0.459).

CONCLUSIONS

The addition of IOM to cases using image guidance does not appear to decrease long-term postoperative neurologic morbidity and may have a reduced diagnostic role given availability of intraoperative image-guidance systems.

Validation of 3D fluoroscopy for image-guidance registration in depth electrode implantation for medically refractory epilepsy

BACKGROUND

Frame registration is a critical step to ensure accurate electrode placement in stereotactic procedures such as stereoelectroencephalography (SEEG) and is routinely done by merging a computed tomography (CT) scan with the preoperative magnetic resonance (MR) examination. Three-dimensional fluoroscopy (XT) has emerged as a method for intraoperative electrode verification following electrode implantation and more recently has been proposed as a registration method with several advantages.

METHODS

We compared the accuracy of SEEG electrode placement by frame registration with CT and XT imaging by analyzing the Euclidean distance between planned and post-implantation trajectories of the SEEG electrodes to calculate the error in both the entry (EP) and target (TP) points. Other variables included radiation dose, efficiency, and complications.

RESULTS

Twenty-seven patients (13 CT and 14 XT) underwent placement of SEEG electrodes (319 in total). The mean EP and TP errors for the CT group were 2.3 mm and 3.3 mm, respectively, and 1.9 mm and 2.9 mm for the XT group, with no statistical difference (p = 0.75 and p = 0.246). The time to first electrode placement was similar (XT, 82 ± 10 min; CT, 84 ± 22 min; p = 0.858) and the average radiation exposure with XT (234 ± 55 mGy*cm) was significantly lower than CT (1245 ± 123 mGy*cm) (p < 0.0001). Four complications were documented with equal incidence in both groups.

CONCLUSIONS

The use of XT as a method for registration resulted in similar implantation accuracy compared with CT. Advantages of XT are the substantial reduction in radiation dose and the elimination of the need to transfer the patient out of the room which may have an impact on patient safety and OR efficiency.