Radiation exposure and reduction in the operating room: Perspectives and future directions in spine surgery

Exposure to procedural ionizing radiation and cancer risk among physicians

BACKGROUND

Physicians in certain specialities are routinely exposed to procedural ionizing radiation. Their risk of cancer is unknown, including by cancer sub-types.

AIMS

To assess cancer risk among exposed physicians.

METHODS

This population-based case-control study was completed in Ontario, Canada, where healthcare is universal, using linkage of physician billing claims to a province-wide cancer registry. Up to five cancer-free physician controls were matched to each cancer-affected physician, by sex, and both age at and year of, entry into practice. Cumulative exposure to procedural ionizing radiation was captured by physician billing claims. Conditional logistic regression generated an odds ratio (OR) of cancer per 1000 procedures performed and as a binary exposure comparing physicians above the upper 95th percentile cumulative number of procedures (≥200) to those below this cut point.

RESULTS

Mean (standard deviation) age of the 1265 cases and 5772 non-cancer controls was 39.7 (10.7) and 37.7 (9.0) years, and 45% and 49% were female, respectively. After a median (interquartile ranges) of 13.0 (6.9-20.4) and 12.5 (6.5-20.1) years of lookback among cases and controls, the OR of cancer was 1.02 (95% confidence interval 0.99-1.05; P = NS) per 1000 additional procedures performed. Modelling the cumulative exposure to procedures nonlinearly did not change the observed association (P > 0.40 for each). Comparing physicians above versus below the upper 95th percentile cumulative number of procedures, the OR of cancer was 1.23 (95% confidence interval 0.75-2.01, P = NS).

CONCLUSIONS

Physician exposure to procedural ionizing radiation was not associated with a higher risk of cancer. Measures that minimize radiation exposure should continue.

Intraoperative MRI: A Review of Applications Across Neurosurgical Specialties

Intraoperative MRI (iMRI) made its debut to great fanfare in the mid-1990s. However, the enthusiasm for this technology with seemingly obvious benefits for neurosurgeons has waned. We review the benefits and utility of iMRI across the field of neurosurgery and present an overview of the evidence for iMRI for multiple neurosurgical disciplines: tumor, skull base, vascular, pediatric, functional, and spine. Publications on iMRI have steadily increased since 1996, plateauing with approximately 52 publications per year since 2011. Tumor surgery, especially glioma surgery, has the most evidence for the use of iMRI contributing more than 50% of all iMRI publications, with increased rates of gross total resection in both adults and children, providing a potential survival benefit. Across multiple neurosurgical disciplines, the ability to use a multitude of unique sequences (diffusion tract imaging, diffusion-weighted imaging, magnetic resonance angiography, blood oxygenation level-dependent) allows for specialization of imaging for various types of surgery. Generally, iMRI allows for consideration of anatomic changes and real-time feedback on surgical outcomes such as extent of resection and instrument (screw, lead, electrode) placement. However, implementation of iMRI is limited by cost and feasibility, including the need for installation, shielding, and compatible tools. Evidence for iMRI use varies greatly by specialty, with the most evidence for tumor, vascular, and pediatric neurosurgery. The benefits of real-time anatomic imaging, a lack of radiation, and evaluation of surgical outcomes are limited by the cost and difficulty of iMRI integration. Nonetheless, the ability to ensure patients are provided by a maximal yet safe treatment that specifically accounts for their own anatomy and highlights why iMRI is a valuable and underutilized tool across multiple neurosurgical subspecialties.

Five historical innovations that have shaped modern orthopaedic surgery

Throughout history, many innovations have contributed to the development of modern orthopaedic surgery, improving patient outcomes and expanding the range of treatment options available to patients. This article explores five key historical innovations that have shaped modern orthopaedic surgery: X-ray imaging, bone cement, the Thomas splint, the Pneumatic tourniquet and robotic-assisted surgery. We will review the development, impact and significance of each innovation, highlighting their contributions to the field of orthopaedic surgery and their ongoing relevance in contemporary and perioperative practice.

Assessing intraoperative pedicle screw placement accuracy using biplanar radiographs compared to three-dimensional imaging

To date, biplanar imaging (2D) has been the method of choice for pedicle screw (PS) positioning and verified for the anteroposterior view and (spinal midline) M-line method. In recent years, the use of intraoperative three-dimensional (3D) imaging has become available with the Gertzbein-Robbins system (GRS) to assess PS breach and positioning confirmation. The aim is to determine if 2D imaging is sufficient to assess PS position in comparison to advanced 3D imaging.Retrospective review of prospectively collected data from 204 consecutive adult patients who underwent posterior thoracic and lumbar instrumented fusion for degenerative spinal surgery by a single surgeon (2019-2022).Of the 204 patients, 187 (91.6%) had intraoperative images available for analysis. A total of 1044 PS implants were used; 922 (88.3%) were robotically placed. Postoperative CT scans were verified with M-line/GRS findings. Among 103 patients (50.5%) with a total of 362 screws, (34.7%) had postoperative CT, intraoperative 3D scan, and intraoperative 2D scan for analysis. Postoperative CT findings were consistent with all GRS findings, validating that 3D imaging was accurate. Screws (1%) were falsely verified by the M-line as 3D imaging confirmed false negative or positive findings.In our series, intraoperative 3D scan was as accurate as postoperative CT scan in assessing PS breach. A significant number of PS may be falsely read as accurate on 2D imaging, that is in fact inaccurate when assessed on 3D imaging. An intraoperative post-instrumentation 3D scan may be preferable to prevent postoperative recognition of a falsely verified screw on biplanar imaging.

The machine-vision image guided surgery system reduces fluoroscopy time, ionizing radiation and intraoperative blood loss in posterior spinal fusion for scoliosis

PURPOSE

To determine if the novel 3D Machine-Vision Image Guided Surgery (MvIGS) (FLASH™) system can reduce intraoperative radiation exposure, while improving surgical outcomes when compared to 2D fluoroscopic navigation.

METHODS

Clinical and radiographic records of 128 patients (≤ 18 years of age) who underwent posterior spinal fusion (PSF), utilising either MvIGS or 2D fluoroscopy, for severe idiopathic scoliosis were retrospectively reviewed. Operative time was analysed using the cumulative sum (CUSUM) method to evaluate the learning curve for MvIGS.

RESULTS

Between 2017 and 2021, 64 patients underwent PSF using pedicle screws with 2D fluoroscopy and another 64 with the MvIGS. Age, gender, BMI, and scoliosis aetiology were comparable between the two groups. The CUSUM method estimated that the MvIGS learning curve with respect to operative time was 9 cases. This curve consisted of 2 phases: Phase 1 comprises the first 9 cases and Phase 2 the remaining 55 cases. Compared to 2D fluoroscopy, MvIGS reduced intraoperative fluoroscopy time, radiation exposure, estimated blood loss and length of stay by 53%, 62% 44%, and 21% respectively. Scoliosis curve correction was 4% higher in the MvIGS group, without any increase in operative time.

CONCLUSION

MvIGS for screw insertion in PSF contributed to a significant reduction in intraoperative radiation exposure and fluoroscopy time, as well as blood loss and length of stay. The real-time feedback and ability to visualize the pedicle in 3D with MvIGS enabled greater curve correction without increasing the operative time.

State-of-the-Art of Non-Radiative, Non-Visual Spine Sensing with a Focus on Sensing Forces, Vibrations and Bioelectrical Properties: A Systematic Review

In the research field of robotic spine surgery, there is a big upcoming momentum for surgeon-like autonomous behaviour and surgical accuracy in robotics which goes beyond the standard engineering notions such as geometric precision. The objective of this review is to present an overview of the state of the art in non-visual, non-radiative spine sensing for the enhancement of surgical techniques in robotic automation. It provides a vantage point that facilitates experimentation and guides new research projects to what has not been investigated or integrated in surgical robotics. Studies were identified, selected and processed according to the PRISMA guidelines. Relevant study characteristics that were searched for include the sensor type and measured feature, the surgical action, the tested sample, the method for data analysis and the system's accuracy of state identification. The 6DOF f/t sensor, the microphone and the electromyography probe were the most commonly used sensors in each category, respectively. The performance of the electromyography probe is unsatisfactory in terms of preventing nerve damage as it can only signal after the nerve is disturbed. Feature thresholding and artificial neural networks were the most common decision algorithms for state identification. The fusion of different sensor data in the decision algorithm improved the accuracy of state identification.

Novel Machine Vision Image Guidance System Significantly Reduces Procedural Time and Radiation Exposure Compared With 2-dimensional Fluoroscopy-based Guidance in Pediatric Deformity Surgery

BACKGROUND

Intraoperative 2-dimensional (2D) fluoroscopy imaging has been commonly adopted for guidance during complex pediatric spinal deformity correction. Despite the benefits, fluoroscopy imaging emits harmful ionizing radiation, which has been well-established to have deleterious effects on the surgeon and operating room staff. This study investigated the difference in intraoperative fluoroscopy time and radiation exposure during pediatric spine surgery between 2D fluoroscopy-based navigation and a novel machine vision navigation system [machine vision image guidance system (MvIGS)].

METHODS

This retrospective chart review was conducted at a pediatric hospital with patients who underwent posterior spinal fusion for spinal deformity correction from 2018 to 2021. Patient allocation to the navigation modality was determined by the date of their surgery and the date of implementation of the MvIGS. Both modalities were the standard of care. Intraoperative radiation exposure was collected from the fluoroscopy system reports.

RESULTS

A total of 1442 pedicle screws were placed in 77 children: 714 using MvIGS and 728 using 2D fluoroscopy. There were no significant differences in the male-to-female ratio, age range, body mass index, distribution of spinal pathologies, number of levels operated on, types of levels operated on, and the number of pedicle screws implanted. Total intraoperative fluoroscopy time was significantly reduced in cases utilizing MvIGS (18.6 ± 6.3 s) compared with 2D fluoroscopy (58.5 ± 19.0 s) ( P < 0.001). This represents a relative reduction of 68%. Intraoperative radiation dose area product and cumulative air kerma were reduced by 66% (0.69 ± 0.62 vs 2.0 ± 2.1 Gycm 2 , P < 0.001) and 66% (3.4 ± 3.2 vs 9.9 ± 10.5 mGy, P < 0.001) respectively. The length of stay displayed a decreasing trend with MVIGS, and the operative time was significantly reduced in MvIGS compared with 2D fluoroscopy for an average of 63.6 minutes (294.5 ± 15.5 vs 358.1 ± 60.6 min, P < 0.001).

CONCLUSION

In pediatric spinal deformity correction surgery, MvIGS was able to significantly reduce intraoperative fluoroscopy time, intraoperative radiation exposure, and total surgical time, compared with traditional fluoroscopy methods. MvIGS reduced the operative time by 63.6 minutes and reduced intraoperative radiation exposure by 66%, which may play an important role in reducing the risks to the surgeon and operating room staff associated with radiation in spinal surgery procedures.

LEVEL OF EVIDENCE

Level III; retrospective comparative study.

Sonification as a reliable alternative to conventional visual surgical navigation

Despite the undeniable advantages of image-guided surgical assistance systems in terms of accuracy, such systems have not yet fully met surgeons' needs or expectations regarding usability, time efficiency, and their integration into the surgical workflow. On the other hand, perceptual studies have shown that presenting independent but causally correlated information via multimodal feedback involving different sensory modalities can improve task performance. This article investigates an alternative method for computer-assisted surgical navigation, introduces a novel four-DOF sonification methodology for navigated pedicle screw placement, and discusses advanced solutions based on multisensory feedback. The proposed method comprises a novel four-DOF sonification solution for alignment tasks in four degrees of freedom based on frequency modulation synthesis. We compared the resulting accuracy and execution time of the proposed sonification method with visual navigation, which is currently considered the state of the art. We conducted a phantom study in which 17 surgeons executed the pedicle screw placement task in the lumbar spine, guided by either the proposed sonification-based or the traditional visual navigation method. The results demonstrated that the proposed method is as accurate as the state of the art while decreasing the surgeon's need to focus on visual navigation displays instead of the natural focus on surgical tools and targeted anatomy during task execution.

Knowledge of radiation exposure associated with common trauma imaging modalities among orthopaedic surgeons, emergency medicine physicians, and general surgeons in the United States

BACKGROUND

Few contemporary studies have assessed physicians' knowledge of radiation exposure associated with common imaging studies, especially in trauma care. The purpose of this study was to assess the knowledge of physicians involved in caring for trauma patients regarding the effective radiation doses of musculoskeletal (MSK) imaging studies routinely utilized in the trauma setting.

METHODS

An electronic survey was distributed to United States orthopaedic surgery, general surgery, and emergency medicine (EM) residency programs. Participants were asked to estimate the radiation dose for common imaging modalities of the pelvis, lumbar spine, and lower extremity, in terms of chest X-ray (CXR) equivalents. Physician estimates were compared to the true effective radiation doses. Additionally, participants were asked to report the frequency of discussing radiation risk with patients.

RESULTS

A total of 218 physicians completed the survey; 102 (46.8%) were EM physicians, 88 (40.4%) were orthopaedic surgeons, and 28 (12.8%) were general surgeons. Physicians underestimated the effective radiation doses of nearly all imaging modalities, most notably for pelvic computed tomaography (CT) (median 50 CXR estimation vs. 162 CXR actual) and lumbar CT (median 50 CXR estimation vs. 638 CXR actual). There was no difference between physician specialties regarding estimation accuracy (P=0.133). Physicians who regularly discussed radiation risks with patients more accurately estimated radiation exposure (P=0.007).

CONCLUSION

The knowledge among orthopaedic and general surgeons and EM physicians regarding the radiation exposure associated with common MSK trauma imaging is lacking. Further investigation with larger scale studies is warranted, and additional education in this area may improve care.

Radiation Exposure during Fluoroscopy-Guided Ozone Chemonucleolysis for Lumbar Disc Herniation

Introduction: Radiation exposure is a frequent drawback of spinal surgery, even if X-ray guidance plays a pivotal role in improving the accuracy and safety of spinal procedures. Consequently, radiation protection is essential to reduce potential negative biological effects. The aim of this study was to evaluate patients’ radiation exposure, the radiation dose emission during fluoroscopy-guided ozone chemonucleolysis (OCN), and the potential role of patient characteristics. Methods: The radiation dose emission reports were retrospectively evaluated in patients who underwent single-level OCN for lumbar disc herniation. A generalized linear model (GLM) with a gamma distribution and log link function was used to assess the association between radiation emission and patients’ characteristics such as age, sex, BMI, level of disc herniation, disc height, and site of disc herniation. Results: Two hundred and forty OCN cases were analyzed. A safe and low level of radiation exposure was registered during OCN. The median fluoroscopy time for OCN was 26.3 (19.4−35.9) seconds, the median radiation emission dose was 19.3 (13.2−27.3) mGy, and he median kerma area product (KAP) was 0.46 (0.33−0.68) mGy ⋅ m2. The resulting KAP values were highly dependent on patient variables. In particular, sex, obesity, and residual disc height < 50% significantly increased the measured KAP, while levels of disc herniations other than L5-S1 reduced the KAP values. Conclusions: The radiation exposure during OCN is low and quite similar to a simple discography. However, patient characteristics are significantly related to radiation exposure and should be carefully evaluated before planning OCN.

Accuracy and Safety of Robot-Assisted versus Fluoroscopy-Guided Posterior C1 Lateral Mass and C2 Pedicle Screw Internal Fixation for Atlantoaxial Dislocation: A Preliminary Study

Objective

To compare the accuracy, efficiency, and safety of robotic assistance (RA) and conventional fluoroscopy guidance for the placement of C1 lateral mass and C2 pedicle screws in posterior atlantoaxial fusion.

Methods

The data of patients who underwent posterior C1–C2 screw fixation (Goel-Harm's technique) in our hospital from August 2014 to March 2021 were retrospectively evaluated, including 14 cases under fluoroscopic guidance and 11 cases under RA. The hospital records, radiographic results, surgical data, and follow-up records were reviewed. Accuracy of screw placement was assessed using the Gertzbein and Robbins scale, and clinical outcomes were evaluated by Japanese Orthopedic Association (JOA) score, visual analogue scale (VAS), modified MacNab criteria, and postoperative complications.

Results

Baseline characteristics of both groups were similar. The mean estimated blood loss in the fluoroscopic guidance and RA groups was 205.7 ± 80.3 mL and 120.9 ± 31.9 mL, respectively (p = 0.03). The mean surgical duration was 34 min longer with RA compared to that performed with free-hand (FH) method (p = 0.15). In addition, lower intraoperative radiation exposure was detected in the RA group (12.4 ± 1.4 mGy/screw) versus the FH (19.9 ± 2.1 mGy/screw) group (p = 0.01). The proportion of “clinically acceptable” screws (graded 0 and I) was higher in the RA group (93.2%) than that in the FH group (87.5%, p = 0.04). There was no significant difference in the increase of JOA score and decrease of VAS score between the two surgical procedures. Furthermore, there were no significant differences in overall clinical outcome between the two groups and no neurovascular complications associated with screw insertion.

Conclusions

RA is a safe and potentially more accurate alternative to the conventional fluoroscopic-guided FH technique for posterior atlantoaxial internal fixation.

Atlantoaxial posterior screw fixation using intra-operative spinal navigation with three-dimensional isocentric C-arm fluoroscopy

PURPOSE

Intra-operative image acquisition coupled with navigation aims to increase screw placement accuracy, and it is particularly helpful in complex spinal procedures. The aim of this study is to analyze the accuracy and reliability of posterior atlanto-axial fixation using spinal navigation combined with intra-operative 3D isocentric C-arm.

METHODS

We retrospectively reviewed all patients presenting with C1-C2 instability and treated by posterior atlanto-axial fixation in our center between December 2016 and September 2018. Screw positioning was guided by intra-operative navigation, registered with surface matching procedure on a previously obtained CT scan and controlled by intra-operative 3D isocentric C-arm. Age, sex, pre- and post-operative neurological status, duration of surgery, presence/absence of vertebral artery injury, and screw placement were retrospectively collected from patients' records. All patients underwent clinical and radiological follow-up at three months after surgery. Radiological assessment of screw positioning was performed by an independent radiologist using the Gertzbein and Robbins grading.

RESULTS

N = 11 (7F, 4 M) consecutive patients were included, with a mean age of 72 years (range from 51 to 85). N = 44 navigated screws were inserted and controlled with intra-operative 3D fluoroscopy at the end of the procedure. An acceptable screw positioning (Gertzbein-Robbins grade A and B) was obtained in all cases (100%). No vertebral artery injury was observed. Mean operating time was 123 minutes. At three months, no screw loosening or displacement was observed.

CONCLUSION

In our experience, spinal navigation coupled with intra-operative 3D fluoroscopy proved to be reliable and safe for C1-C2 screw placement.

Accuracy of Robot-Assisted Percutaneous Pedicle Screw Placement under Regional Anesthesia: A Retrospective Cohort Study

Background

Robot-assisted pedicle screw placement is usually performed under general anesthesia to keep the body still. The aim of this study was to compare the accuracy of the robot-assisted technique under regional anesthesia with that of conventional fluoroscopy-guided percutaneous pedicle screw placement under general anesthesia in minimally invasive lumbar fusion surgery.

Methods

This study recruited patients who underwent robot-assisted percutaneous endoscopic lumbar interbody fusion (PELIF) or fluoroscopy-guided minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) between December 2017 and February 2020 at a single center. Based on the method of percutaneous pedicle screw placement used, patients were divided into the robot-assisted under regional anesthesia (group RE-RO) and fluoroscopy-guided under general anesthesia (group GE-FLU) groups. The primary outcome measures were screw accuracy and the incidence of facet joint violation (FJV). Secondary outcome measures included X-ray and visual analogue scale (VAS) scores which were used to evaluate the degree of the postoperative pain at 4 hours and on postoperative days 1, 2, and 3. Intraoperative adverse events were also recorded.

Results

Eighteen patients were included in group RE-RO, and 23 patients were included in group GE-FLU. The percentages of clinically acceptable screws (Gertzbein and Robbins grades A and B) were 94.4% and 91.5%, respectively. There was no significant difference in the percentages of clinically acceptable screws (p=0.44) or overall Gertzbein and Robbins screw accuracy grades (p=0.35). Only the top screws were included in the analysis of FJVs. The percentages of FJV (Babu grades 1, 2, and 3) were 5.6% and 28.3%, respectively. This difference was statistically significant (p=0.01). Overall, the FJV grades in group RE-RO were significantly better than those in group GE-FLU (p=0.009). The mean fluoroscopy time for each screw in group RE-RO was significantly shorter than that in group GE-FLU (group RE-RO: 5.4 ± 1.9 seconds and group GE-FLU: 6.8 ± 2.0 seconds; p=0.03). The postoperative pain between the RE-RO and GE-FLU groups was not statistically significant. The intraoperative adverse events included 1 case of registration failure and 1 case of guide-wire dislodgment in group RE-RO, as well as 2 cases of screw misplacement in group GE-FLU. No complications related to anesthesia were observed.

Conclusion

Robot-assisted pedicle screw placement under regional anesthesia can be performed effectively and safely. The accuracy is comparable to the conventional technique. Moreover, this technique has the advantage of fewer FJVs and a lower radiation time.

Minimising radiation exposure to the surgeon in minimally invasive spine surgeries: A systematic review of 15 studies

BACKGROUND

Intraoperative imaging in minimally invasive spinal surgeries is associated with significant radiation exposure to surgeons, which overtime can lead to serious health hazards including malignancy. In this study, the authors conducted a systematic review to evaluate the efficacy of navigation assisted fluoroscopy methods on radiation exposure to the surgeon in minimally invasive spine surgeries, percutaneous endoscopic lumbar discectomy/percutaneous endoscopic transforaminal discectomy versus minimally invasive spine transforaminal lumbar interbody fusion (PELD/PETD versus MIS-TLIF).

METHODS

A systematic literature search was conducted using PUBMED/MEDLINE on 20th July, 2020. Inclusion criteria were applied according to study design, surgical technique, spinal region, and language. Data extracted included lumbar segment, average operation time (min), fluoroscopic time (s), and radiation dose (μSV), efficacy of modified navigation versus conventional techniques; on reducing operation, fluoroscopy times and effective radiation dose.

RESULTS

Fifteen studies (ten prospectives, and five retrospectives) were included for quantitative analysis. PELD recorded a shorter operation time (by 126.3min, p<0.001) and fluoroscopic time (by 22.9s, p=0.3) than MIS-TLIF. The highest radiation dose/case (μSV) for both techniques were recorded at the surgeon's: finger, chest, neck and eye. The effective dose for MIS-TLIF was 30μSV higher than PELD. Modified navigation techniques recorded a shorter operation time (by 15.9min, p=0.3); fluoroscopy time (by 289.8s, p=0.3); effective radiation dose (by 169.5μSV, p=0.3) than conventional fluoroscopy methods.

DISCUSSION

This systematic literature review showed that although navigation assisted fluoroscopy techniques are superior to conventional methods in minimising radiation exposure, lack of statistical significance warrants future randomised controlled trials, to solidify their efficacy in reducing radiation related hazards.

Computational modelling of the scoliotic spine: A literature review

Scoliosis is a deformity of the spine that in severe cases requires surgical treatment. There is still disagreement among clinicians as to what the aim of such treatment is as well as the optimal surgical technique. Numerical models can aid clinical decision-making by estimating the outcome of a given surgical intervention. This paper provided some background information on the modelling of the healthy spine and a review of the literature on scoliotic spine models, their validation, and their application. An overview of the methods and techniques used to construct scoliotic finite element and multibody models was given as well as the boundary conditions used in the simulations. The current limitations of the models were discussed as well as how such limitations are addressed in non-scoliotic spine models. Finally, future directions for the numerical modelling of scoliosis were addressed.

A real-time 3D electromagnetic navigation system for percutaneous pedicle screw fixation in traumatic thoraco-lumbar fractures: implications for efficiency, fluoroscopic time, and accuracy compared with those of conventional fluoroscopic guidance

PURPOSE

Navigation is becoming more useful in percutaneous pedicle screw fixation (PPSF). The aim of this study was to compare the efficiency, fluoroscopic time, accuracy, and clinical outcomes of PPSF with a novel electromagnetic navigation (EMN) system for thoraco-lumbar (TL) fractures with those of PPSF with conventional C-arm fluoroscopic (CF) guidance.

METHODS

A retrospective study was conducted. A total of 162 screws were implanted in 29 patients with the assistance of the EMN system (EMN group), and 220 screws were inserted in 40 patients by using CF guidance (CF group). The duration of surgery, placement time per screw, fluoroscopic time per screw, accuracy of pedicle screw placement, and clinical outcomes were compared between the two groups.

RESULTS

The duration of surgery and placement time per screw in the EMN group were significantly lower than those in the CF group (P < 0.05). The fluoroscopic time per screw in the CF group was significantly longer than that in the EMN group (P < 0.05). The learning curve of PPSF in the EMN group was steeper than that in the CF group. The accuracy of pedicle screw placement in the EMN group was more precise than that in the CF group (P < 0.05). The VAS scores in the EMN group were significantly lower than those in the CF group at one-week postoperatively (P < 0.05).

CONCLUSION

Compared with PPSF by using conventional fluoroscopic guidance, PPSF with the aid of the EMN system can increase the efficiency and accuracy of pedicle screw placement and reduce the fluoroscopic time.

Augmented reality in the operating room: a clinical feasibility study

Background

Augmented Reality (AR) is a rapidly emerging technology finding growing acceptance and application in different fields of surgery. Various studies have been performed evaluating the precision and accuracy of AR guided navigation. This study investigates the feasibility of a commercially available AR head mounted device during orthopedic surgery.

Methods

Thirteen orthopedic surgeons from a Swiss university clinic performed 25 orthopedic surgical procedures wearing a holographic AR headset (HoloLens, Microsoft, Redmond, WA, USA) providing complementary three-dimensional, patient specific anatomic information. The surgeon’s experience of using the device during surgery was recorded using a standardized 58-item questionnaire grading different aspects on a 100-point scale with anchor statements.

Results

Surgeons were generally satisfied with image quality (85 ± 17 points) and accuracy of the virtual objects (84 ± 19 point). Wearing the AR device was rated as fairly comfortable (79 ± 13 points). Functionality of voice commands (68 ± 20 points) and gestures (66 ± 20 points) provided less favorable results. The greatest potential in the use of the AR device was found for surgical correction of deformities (87 ± 15 points). Overall, surgeons were satisfied with the application of this novel technology (78 ± 20 points) and future access to it was demanded (75 ± 22 points).

Conclusion

AR is a rapidly evolving technology with large potential in different surgical settings, offering the opportunity to provide a compact, low cost alternative requiring a minimum of infrastructure compared to conventional navigation systems. While surgeons where generally satisfied with image quality of the here tested head mounted AR device, some technical and ergonomic shortcomings were pointed out. This study serves as a proof of concept for the use of an AR head mounted device in a real-world sterile setting in orthopedic surgery.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-021-04339-w.

RADIATION EXPOSURE TO THE BACK WITH DIFFERENT TYPES OF APRONS

Physicians and nurses stand with their back towards the C-arm fluoroscope when using the computer, taking things out of closets and preparing drugs for injection or instruments for intervention. This study was conducted to investigate the relationship between the type of lead apron and radiation exposure to the backs of physicians and nurses while using C-arm fluoroscopy. We compared radiation exposure to the back in the three groups: no lead apron (group C), front coverage type (group F) and wrap-around type (group W). The other wrap-around type apron was put on the bed instead of on a patient. We ran C-arm fluoroscopy 40 times for each measurement. We collected the air kerma (AK), exposure time (ET) and effective dose (ED) of the bedside table, upper part and lower part of apron. We measured these variables 30 times for each location. In group F, ED of the upper part was the highest (p < 0.001). ED of the lower part in group C and F was higher than that in group W (p = 0.012). The radiation exposure with a front coverage type apron is higher than that of the wrap-around type and even no apron at the neck or thyroid. For reducing radiation exposure to the back of physician or nurse, the wrap-around type apron is recommended. This type of apron can reduce radiation to the back when the physician turns away from the patient or C-arm fluoroscopy.

An iterative reconstruction method for sparse-projection data for low-dose CT

Reducing X-ray radiation is beneficial for reducing the risk of cancer in patients. There are two main approaches for achieving this goal namely, one is to reduce the X-ray current, and another is to apply sparse-view protocols to do image scanning and projections. However, these techniques usually lead to degradation of the reconstructed image quality, resulting in excessive noise and severe edge artifacts, which seriously affect the diagnosis result. In order to overcome such limitation, this study proposes and tests an algorithm based on guided kernel filtering. The algorithm combines the characteristics of anisotropic edges between adjacent image voxels, expresses the relevant weights with an exponential function, and adjusts the weights adaptively through local gray gradients to better preserve the image structure while suppressing noise information. Experiments show that the proposed method can effectively suppress noise and preserve the image structure. Comparing with similar algorithms, the proposed algorithm greatly improves the peak signal-to-noise ratio (PSNR), structural similarity (SSIM), and root mean square error (RMSE) of the reconstructed image. The proposed algorithm has the best effect in quantitative analysis, which verifies the effectiveness of the proposed method and good image reconstruction performance. Overall, this study demonstrates that the proposed method can reduce the number of projections required for repeated CT scans and has potential for medical applications in reducing radiation doses.

Are Continued Efforts to Reduce Radiation Exposures from X-Rays Warranted?

There are pressures to avoid use of radiological imaging throughout all healthcare due to the notion that all radiation is carcinogenic. This perception stems from the long-standing use of the linear no-threshold (LNT) assumption of risk associated with radiation exposures. This societal perception has led to relentless efforts to avoid and reduce radiation exposures to patients at great costs. Many radiation reduction campaigns have been launched to dissuade doctors from using radiation imaging. Lower-dose imaging techniques and practices are being advocated. Alternate imaging procedures are encouraged. Are these efforts warranted? Based on recent evidence, LNT ideology is shown to be defunct for risk assessment at low-dose exposure ranges which includes X-rays and CT scans. In fact, the best evidence that was once used to support LNT ideology, including the Life Span Study data, now indicates thresholds for cancer induction are high; therefore, low-dose X-rays cannot cause harm. Current practices are safe as exposures currently encountered are orders of magnitude below threshold levels shown to be harmful. As long as imaging is medically warranted, it is shown that efforts to reduce exposures that are within background radiation levels and that are also shown to enhance health by upregulating natural adaptive protection systems are definitively wasted resources.

Radiation Concerns for the Neuroanesthesiologists

With the advent of minimally invasive neurosurgical techniques and rapid innovations in the field of neurointervention, there has been a sharp rise in diagnostic and therapeutic modalities requiring radiation exposure. Neuroanesthesiologists are currently involved in various procedures inside as well as outside the operating room (OR) like intensive care units, interventional suites, and gamma knife units. The ambit expands from short-lasting diagnostic scans to lengthy therapeutic procedures performed under fluoroscopic guidance. Hence, a modern-day neuroanesthesiologist has to bear the brunt of the radiation exposure in both inside and outside the OR. However, obliviousness and nonadherence to the relevant radiation safety measures are still prevalent. Radiation protection and safety are topics that need to be discussed with new vigor in the light of current practice.

Device profile of the XVision-spine (XVS) augmented-reality surgical navigation system: overview of its safety and efficacy

Introduction: The field of augmented reality mediated spine surgery is growing rapidly and holds great promise for improving surgical capabilities and patient outcomes. Augmented reality can assist with complex or atypical cases involving challenging anatomy. As neuronavigation evolves, fundamental technical limitations remain in line-of-sight interruption and operator attention shift, which this novel augmented reality technology helps to address.Areas covered: XVision is a recently FDA-approved head mounted display for intraoperative neuronavigation, compatible with all current conventional pedicle screw technology. The device is a wireless, customizable headset with an integrated surgical tracking system and transparent retinal display. This review discusses the available literature on the safety and efficacy of XVision, as well as the current state of augmented reality technology in spine surgery.Expert opinion: Augmented-reality spine surgery is an emerging technology that may increase precision, efficiency, and safety as well as decrease radiation exposure of manual and robotic computer-navigated pedicle screw insertion techniques. The initial clinical experience with XVision has shown good outcomes and it has received positive operator feedback. Now that initial clinical safety and efficacy has been demonstrated, ongoing experience must be studied to empirically validate this technology and generate further innovation in this rapidly evolving field.

A novel computer navigation model guided unilateral percutaneous vertebroplasty for vertebral compression fracture: A case report

RATIONAL

Vertebral compression fracture (VCF) is one of the most common diseases in spinal surgery. Traditional percutaneous vertebroplasty (PVP) under fluoroscopy is an effective method to treat vertebral compression fracture. However, there is still a risk of vascular nerve injury and infection caused by inaccurate or repeated puncture. Therefore, the purpose of this paper was to assess the accuracy of unilateral PVP guided by screw view model of navigation (SVMN) for VCF.

PATIENT CONCERNS

A 59-year-old female patient suffered high falling injury, and with back pain as its main clinical symptom.

DIAGNOSES

The patient was diagnosed with a L1 VCF.

INTERVENTIONS

We placed the puncture needle under the guidance of SVMN to reach the ideal position designed before operation, and then injected the bone cement to complete the percutaneous kyphoplasty (PKP).

OUTCOMES

The operative time was 29.5 minutes, the puncture time was 1 time, the fluoroscopy time was 2.9 minutes, and the bone cement distribution was satisfactory. VAS and ODI scores were significant improved postoperatively. No surgical complications, including neurovascular injury and infection, were observed during 28-month follow up.

LESSONS

The SVMN guided percutaneous puncture needle insertion in PKP operation for VCF is an effective and safety technique. Besides, the SVMN has also been a contributor to reduce radiation doses and replace conventional fluoroscopy.

Is it mandatory to routinely use image intensifier during scoliosis surgery? – Results of an email survey

Background

Methods

Results

Conclusions

A Review of Orthopaedic Surgical Set-Up and Introduction of the TULIPS Mnemonic - Six Simple Steps for Optimising Set-Up in Orthopaedic Surgery

Conducting a thorough check to ensure that all equipment and personnel are positioned correctly at the start of any operation is essential for both the safety of the surgical team and the patient outcome. Orthopaedic surgery in particular carries a high risk of occupational injury and this group could benefit greatly from ergonomic improvements. This review highlights multiple factors that can influence safety of surgeons, surgical efficiency and patient outcomes. "TULIPS" is a mnemonic that lists six key steps in optimising the surgical procedure through effective positioning of equipment and personnel pre-operatively. This was trialled by distribution amongst orthopaedic registrars regionally and it received excellent feedback, with the majority changing their current practice. Here we report that using this simple and memorable checklist can assist orthopaedic surgeons in setting up the operating theatre, facilitating ergonomic improvements that can reduce the risk of musculoskeletal injury and radiation exposure.

Radiation exposure of a mobile 3D C-arm with large flat-panel detector for intraoperative imaging and navigation - an experimental study using an anthropomorphic Alderson phantom

Background

Intraoperative 3-dimensional (3D) navigation is increasingly being used for pedicle screw placement. For this purpose, dedicated mobile 3D C-arms are capable of providing intraoperative fluoroscopy-based 3D image data sets. Modern 3D C-arms have a large field of view, which suggests a higher radiation exposure. In this experimental study we therefore investigate the radiation exposure of a new mobile 3D C-arm with large flat-panel detector to a previously reported device with regular flat-panel detector on an Alderson phantom.

Methods

We measured the radiation exposure of the Vision RFD 3D (large 30 × 30 cm detector) while creating 3D image sets as well as standard fluoroscopic images of the cervical and lumbar spine using an Alderson phantom. The dosemeter readings were then compared with the radiation exposure of the previous model Vision FD Vario 3D (smaller 20 × 20 cm detector), which had been examined identically in advance and published elsewhere.

Results

The larger 3D C-arm induced lower radiation exposures at all dosemeter sites in cervical 3D scans as well as at the sites of eye lenses and thyroid gland in lumbar 3D scans. At ​​male and especially female gonads in lumbar 3D scans, however, the larger 3D C-arm showed higher radiation exposures compared with the smaller 3D C-arm. In lumbar fluoroscopic images, the dosemeters near/in the radiation field measured a higher radiation exposure using the larger 3D C-arm.

Conclusions

The larger 3D C-arm offers the possibility to reduce radiation exposures for specific applications despite its larger flat-panel detector with a larger field of view. However, due to the considerably higher radiation exposure of the larger 3D C-arm during lumbar 3D scans, the smaller 3D C-arm is to be recommended for short-distance instrumentations (mono- and bilevel) from a radiation protection point of view. The larger 3D C-arm with its enlarged 3D image set might be used for long instrumentations of the lumbar spine. From a radiation protection perspective, the use of the respective 3D C-arm should be based on the presented data and the respective application.

Inside-Out Approach of Lumbar Endoscopic Unilateral Laminotomy for Bilateral Decompression: A Detailed Technical Description, Rationale and Outcomes

Although lumbar stenosis was recognized as a contraindication for endoscopic spine surgery in the past, the advancement in endoscopic system design and development of approach techniques and strategies now enabled the endoscopic spine surgeons to manage all types of lumbar stenosis safely and more effectively. A full-endoscopic lumbar technique for surgical management of spinal canal stenosis is now used today in many advanced spine centers around the world as one of their standard procedures which can be done under general, regional, local anesthesia with sedation. In this technical report, we described in detail the inside-out approach of performing lumbar endoscopic unilateral laminotomy with bilateral decompression (LE-ULBD) and retrospectively reviewed hospital records of 127 patients who underwent the approach from December 2018 to March 2019 to address 1 level lumbar spinal stenosis and determined its outcome after 12-month follow-up period. Perioperative outcomes, operation time, length of hospital stay, and surgical complications were recorded and analyzed. The cross-sectional area of the thecal sac at the operated level was measured. The visual analogue scale (VAS) was assessed preoperatively, 1 month, and 12 months as well as the Oswestry Disability Index (ODI). The data were statistically analyzed (using SPSS ver. 17.0). The inside-out approach LE-ULBD was shown to effect statistically significant improvement in the VAS of leg and back pain as well as the ODI. It is a familiar, safe, and effective way of performing spinal stenosis decompression with good reproducible outcomes.

Augmented reality-based navigation increases precision of pedicle screw insertion

Background

Precise insertion of pedicle screws is important to avoid injury to closely adjacent neurovascular structures. The standard method for the insertion of pedicle screws is based on anatomical landmarks (free-hand technique). Head-mounted augmented reality (AR) devices can be used to guide instrumentation and implant placement in spinal surgery. This study evaluates the feasibility and precision of AR technology to improve precision of pedicle screw insertion compared to the current standard technique.

Methods

Two board-certified orthopedic surgeons specialized in spine surgery and two novice surgeons were each instructed to drill pilot holes for 40 pedicle screws in eighty lumbar vertebra sawbones models in an agar-based gel. One hundred and sixty pedicles were randomized into two groups: the standard free-hand technique (FH) and augmented reality technique (AR). A 3D model of the vertebral body was superimposed over the AR headset. Half of the pedicles were drilled using the FH method, and the other half using the AR method.

Results

The average minimal distance of the drill axis to the pedicle wall (MAPW) was similar in both groups for expert surgeons (FH 4.8 ± 1.0 mm vs. AR 5.0 ± 1.4 mm, p = 0.389) but for novice surgeons (FH 3.4 mm ± 1.8 mm, AR 4.2 ± 1.8 mm, p = 0.044).

Expert surgeons showed 0 primary drill pedicle perforations (PDPP) in both the FH and AR groups. Novices showed 3 (7.5%) PDPP in the FH group and one perforation (2.5%) in the AR group, respectively (p > 0.005).

Experts showed no statistically significant difference in average secondary screw pedicle perforations (SSPP) between the AR and the FH set 6-, 7-, and 8-mm screws (p > 0.05). Novices showed significant differences of SSPP between most groups: 6-mm screws, 18 (45%) vs. 7 (17.5%), p = 0.006; 7-mm screws, 20 (50%) vs. 10 (25%), p = 0.013; and 8-mm screws, 22 (55%) vs. 15 (37.5%), p = 0.053, in the FH and AR group, respectively. In novices, the average optimal medio-lateral convergent angle (oMLCA) was 3.23° (STD 4.90) and 0.62° (STD 4.56) for the FH and AR set screws (p = 0.017), respectively. Novices drilled with a higher precision with respect to the cranio-caudal inclination angle (CCIA) category (p = 0.04) with AR.

Conclusion

In this study, the additional anatomical information provided by the AR headset superimposed to real-world anatomy improved the precision of drilling pilot holes for pedicle screws in a laboratory setting and decreases the effect of surgeon’s experience. Further technical development and validations studies are currently being performed to investigate potential clinical benefits of the herein described AR-based navigation approach.

Conventional versus stereotactic image guided pedicle screw placement during spinal deformity correction: a retrospective propensity score-matched study of a national longitudinal database

PURPOSE/AIM

To compare complications, readmissions, revisions, and payments between navigated and conventional pedicle screw fixation for treatment of spine deformity.

METHODS

The Thomson Reuters MarketScan national longitudinal database was used to identify patients undergoing osteotomy, posterior instrumentation, and fusion for treatment of spinal deformity with or without image-guided navigation between 2007-2016. Conventional and navigated groups were propensity-matched (1:1) to normalize differences between demographics, comorbidities, and surgical characteristics. Clinical outcomes and charges were compared between matched groups using bivariate analyses.

RESULTS

A total of 4,604 patients were identified as having undergone deformity correction, of which 286 (6.2%) were navigated. Propensity-matching resulted in a total of 572 well-matched patients for subsequent analyses, of which half were navigated. Rate of mechanical instrumentation-related complications was found to be significantly lower for navigated procedures (p = 0.0371). Navigation was also associated with lower rates of 90-day unplanned readmissions (p = 0.0295), as well as 30- and 90-day postoperative revisions (30-day: p = 0.0304, 90-day: p = 0.0059). Hospital, physician, and total payments favored the conventional group for initial admission (p = 0.0481, 0.0001, 0.0019, respectively); however, when taking into account costs of readmissions, hospital payments became insignificantly different between the two groups.

CONCLUSIONS

Procedures involving image-guided navigation resulted in decreased instrumentation-related complications, unplanned readmissions, and postoperative revisions, highlighting its potential utility for the treatment of spine deformity. Future advances in navigation technologies and methodologies can continue to improve clinical outcomes, decrease costs, and facilitate widespread adoption of navigation for deformity correction.

Intraoperative radiation exposure in hip arthroscopy: a systematic review

Fluoroscopy is used in hip arthroscopy (HA) for portal placement, instrument localisation, and guidance in bony resection. The recent increase in arthroscopic hip procedures may place patients and surgeons at risk for increased radiation exposure and radiation-induced complications. The purpose of the current systematic review was to assess intraoperative radiation exposure in HA. The systematic review was conducted according to PRISMA guidelines; inclusion criteria were studies assessing radiation exposure in HA. 9 studies including 994 patients were included. Mean age was 38.6 years and 48% (436 of 906) were female. Mean time of fluoroscopy exposure was 0.58 minutes. Dose area product was 129.5 cGycm². Mean intraoperative absorbed radiation dose studies was 12.6 mGy. Mean intraoperative effective dose was 0.48 mSv. The mean occupational exposure to the surgeon per case was 0.0031 mSv. Higher patient body mass index (BMI) correlated to greater patient effective and cumulative dose (p < 0.05, r = 0.404), and greater occupational exposure (p < 0.001, r = 0.460). Increasing surgeon experience decreased fluoroscopy time (p = 0.039) and radiation dose (p = 0.002). Radiation dose and effective dose were well under the thresholds for deterministic effects (2 Gy) and annual radiation exposure for occupational workers (20 mSv). Intraoperative radiation exposure to patients and surgeons is within acceptable annual radiation limits. Ensuring careful selection of perioperative imaging modalities, proper protective shielding, specifically the use of leaded eyeglasses, and optimal C-arm positioning are key strategies to reduce radiation exposure to patients and surgeons alike.

Reduction of radiation exposure to operating physician and assistant using a real-time auditory feedback dosimeter during femoral artery puncturing: a study on swine model

Background

Real-time dosimeters may create a relatively safer environment not only for the patient but also for the physician and the assistant as well. We propose the use of a real-time radiation measurement dosimeter having auditory feedback to reduce radiation exposure.

Methods

Radiation dose rates were measured for 30 fluoroscopy-guided puncturing procedures of femoral arteries in swine. Fifteen puncturing procedures were performed with real-time radiation measurement dosimeter having auditory feedback and other 15 were performed without auditory feedback dosimeter by an interventional cardiologist with 10 years of experience.

Results

The left body side of the operating physician (38%, p < 0.001) and assistant (25%, p < 0.001) was more exposed as compared to the right body side. Radiation dose rate to the left hand, left arm and left leg were reduced from 0.96 ± 0.10 to 0.79 ± 0.12 mSv/h (17% reduction, p < 0.001), from 0.11 ± 0.02 to 0.07 ± 0.01 mSv/h (36% reduction, p < 0.001) and from 0.22 ± 0.06 to 0.15 ± 0.02 mSv/h (31% reduction, p < 0.001) with the use of auditory feedback dosimeter, respectively. The mean fluoroscopic time was reduced from 4.8 ± 0.43 min to 4.2 ± 0.53 min (p < 0.001). The success rate of performing arterial puncturing was 100%.

Conclusions

The use of auditory feedback dosimeter resulted in reduction in effective dose. The sound beep alerted the physician from the danger of exposure, and this approach induced awareness and protective mindset to the operating physician and assistant.

OPTIMISATION OF PATIENT DOSE AND IMAGE QUALITY IN FLUOROSCOPICALLY GUIDED CERVICAL SPINE SURGERY: A PHANTOM-BASED STUDY

The purpose of the current study was to provide useful data, which may help neurosurgeons to manage the patient dose and image quality in spinal surgery procedures, utilising a phantom and a test object. The kerma area product, cumulative dose (CD) and entrance surface dose (ESD) rate on the phantom and image intensifier were measured, for selectable fields of view (FOVs), fluoroscopy modes, two geometric magnifications and various phantom thicknesses. The images were subjectively evaluated regarding low-contrast detectability and high-contrast resolution. Signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), high-contrast spatial resolution (HCSR) and figure of merit (FOM) values were also estimated. The ESD rates increased with increasing phantom thickness, when using electronic or geometric magnification, continuous or high-definition fluoroscopy (HDF). The observers' evaluation showed relatively slight changes in image quality when pulsed fluoroscopy was used. SNR, CNR and HCSR values decreased with increasing phantom thicknesses, while remained almost constant when using pulsed fluoroscopy. SNR and HCSR improved in HDF, while the CNR remained almost constant only for the FOVs 23 and 17 cm. By applying electronic magnification, this resulted in improved HCSR. FOM values decreased in HDF, with increasing phantom thickness and using electronic magnification. For the 'thinnest' patients, CD may overestimate skin dose by 25% than the actual values. Geometric magnification resulted in improved FOM, especially for low-dose fluoroscopy and FOV 23 cm. The knowledge of the increments in dose values, image quality and FOM indices concerning phantom thickness may help neurosurgeons to optimise spinal surgery procedures by selecting the appropriate operational parameters, which could contribute toward the establishment of a radiation protection culture.

Intraoperative Computed Tomography Scan for Orbital Fracture Reconstruction

Orbital fractures pose specific challenge in its surgical management. One of the greatest challenges is to obtain satisfactory reconstruction by correct positioning of orbital implant. Intraoperative computed tomography (CT) scan may facilitate this procedure. The aim of this study was to describe the early use of intraoperative CT in orbital fractures repair in our center. The authors assessed the revision types and rates that have occurred with this technique. With the use of pre-surgical planning, optical intraoperative navigation, and intraoperative CT, the impact of intraoperative CT on the management of 5 cases involving a total number of 14 orbital wall fractures were described. There were 6 pure orbital blowout wall fractures reconstructed, involving both medial and inferior wall of the orbit fracturing the transition zone and 8 impure orbital wall fractures in orbitozygomaticomaxillary complex fracture. 4 patients underwent primary and 1 had delayed orbital reconstruction. Intraoperative CT resulted in intraoperative orbital implant revision, following final navigation planning position, in 40% (2/5) of patients or 14% (2/14) of the fractures. In revised cases, both implant repositioning was conducted at posterior ledge of orbit. Intraoperative CT confirmed true to original reconstruction of medial wall, inferior wall and transition zone of the orbit. Two selected cases were illustrated. In conclusion, intraoperative CT allows real-time assessment of fracture reduction and immediate orbital implant revision, especially at posterior ledge. As a result, no postoperative imaging was indicated in any of the patients. Long-term follow-ups for orbital fracture patients managed with intraoperative CT is suggested.

Reduction of operator radiation exposure using a passive robotic device during fluoroscopy-guided arterial puncture: an experimental study in a swine model

Background

Vascular interventions imply radiation exposure to the operating physician (OP). To reduce radiation exposure, we propose a novel passive robotic device for fluoroscopy-guided arterial puncturing.

Methods

X-ray dose rates were measured for a total of 30 fluoroscopy-guided puncture femoral arteries in 15 pigs. Fifteen punctures were performed with the device while the other 15 were performed without the device by an interventional cardiologist with 10 years of experience. Parametric t test was used.

Results

The success rate with the device was 100%. Overall, the OP received more radiation (0.41 mSv/h) as compared to the assistant (0.06 mSv/h) (p <  0.001) and, amongst OP’s body parts, hands received more radiation than other body parts (p <  0.001). The radiation dose rate to the OP’s hands during arterial puncturing performed manually without the device was 0.95 ± 0.25 mSv/h whereas it was 0.14 ± 0.006 mSv/h using the device, resulting in an 85% reduction (p <  0.001). For the head, the dose was reduced from 0.16 mSv/h to 0.08 mSv/h (50% reduction, p <  0.001), and for the dominant arm, from 0.12 mSv/h to 0.07 mSv/h (42% reduction, p <  0.001). The fluoroscopy time was reduced from 4.5 ± 0.15 min to 4.3 ± 0.11 min device (p = 0.002).

Conclusions

In a swine model, fluoroscopy time and radiation exposure for the OP puncturing femoral artery were significantly reduced by using the passive robotic device.

Pedicle screw navigation using surface digitization on the Microsoft HoloLens

PURPOSE

In spinal fusion surgery, imprecise placement of pedicle screws can result in poor surgical outcome or may seriously harm a patient. Patient-specific instruments and optical systems have been proposed for improving precision through surgical navigation compared to freehand insertion. However, existing solutions are expensive and cannot provide in situ visualizations. Recent technological advancement enabled the production of more powerful and precise optical see-through head-mounted displays for the mass market. The purpose of this laboratory study was to evaluate whether such a device is sufficiently precise for the navigation of lumbar pedicle screw placement.

METHODS

A novel navigation method, tailored to run on the Microsoft HoloLens, was developed. It comprises capturing of the intraoperatively reachable surface of vertebrae to achieve registration and tool tracking with real-time visualizations without the need of intraoperative imaging. For both surface sampling and navigation, 3D printable parts, equipped with fiducial markers, were employed. Accuracy was evaluated within a self-built setup based on two phantoms of the lumbar spine. Computed tomography (CT) scans of the phantoms were acquired to carry out preoperative planning of screw trajectories in 3D. A surgeon placed the guiding wire for the pedicle screw bilaterally on ten vertebrae guided by the navigation method. Postoperative CT scans were acquired to compare trajectory orientation (3D angle) and screw insertion points (3D distance) with respect to the planning.

RESULTS

The mean errors between planned and executed screw insertion were [Formula: see text] for the screw trajectory orientation and 2.77±1.46 mm for the insertion points. The mean time required for surface digitization was 125±27 s.

CONCLUSIONS

First promising results under laboratory conditions indicate that precise lumbar pedicle screw insertion can be achieved by combining HoloLens with our proposed navigation method. As a next step, cadaver experiments need to be performed to confirm the precision on real patient anatomy.

Does surgeon experience influence the amount of radiation exposure during orthopedic procedures? A systematic review

With an increasing use of intraoperative fluoroscopy in operating rooms worldwide, the topic of radiation exposure has become a major concern among hospital staff, doctors and patients alike. Since fluoroscopy has become an integral part in orthopedic intraoperative management, we sought to identify whether surgeon grade or experience plays a role in the amount of radiation used and consequently exposed. We performed a systematic review examining the association between surgeon experience and radiation exposure using primary outcome measures (radiation dose and total screening time/fluoroscopy time). To be included in the review, the study population had to compare varying surgeon experience levels and their effect on the primary outcomes. A total of eighteen studies were included in the review. The studies were a mix of prospective and retrospective studies with low to moderate quality as evaluated by the MINORs criteria. Studies were variable in defining surgeon experience levels and in the type of operations being performed. Majority of the studies showed that inexperienced surgeons/trainees had a higher total fluoroscopy time and a higher mean radiation exposure as compared to experienced surgeons. We conclude that higher surgeon experience significantly reduces usage of fluoroscopy and the consequent radiation exposure in orthopedic procedures. Introduction of strict radiation guidelines involving limited usage of fluoroscopy and supervision of trainees may be beneficial in controlling radiation exposure in the future.

Radiation dose and image quality comparison during spine surgery with two different, intraoperative 3D imaging navigation systems

Careful protocol selection is required during intraoperative three-dimensional (3D) imaging for spine surgery to manage patient radiation dose and achieve clinical image quality. Radiation dose and image quality of a Medtronic O-arm commonly used during spine surgery, and a Philips hybrid operating room equipped with XperCT C-arm 3D cone-beam CT (hCBCT) are compared. The mobile O-arm (mCBCT) offers three different radiation dose settings (low, standard, and high), for four different patient sizes (small, medium, large, and extra large). The patient's radiation dose rate is constant during the entire 3D scan. In contrast, C-CBCT spine imaging uses three different field of views (27, 37, and 48 cm) using automatic exposure control (AEC) that modulates the patient's radiation dose rate during the 3D scan based on changing patient thickness. hCBCT uses additional x-ray beam filtration. Small, medium, and large trunk phantoms designed to mimic spine and soft tissue were imaged to assess radiation dose and image quality of the two systems. The estimated measured "patient" dose for the small, medium, and large phantoms imaged by the mCBCT considering all the dose settings ranged from 9.4-27.6 mGy, 8.9-33.3 mGy, and 13.8-40.6 mGy, respectively. The "patient" dose values for the same phantoms imaged with hCBCT were 2.8-4.6 mGy, 5.7-10.0 mGy, and 11.0-15.2 mGy. The CNR for the small, medium, and large phantoms was 2.9 to 3.7, 2.0 to 3.0, and 2.5 to 2.6 times higher with the hCBCT system, respectively. Hounsfield unit accuracy, noise, and uniformity of hCBCT exceeded the performance of the mCBCT; spatial resolution was comparable. Added x-ray beam filtration and AEC capability achieved clinical image quality for intraoperative spine surgery at reduced radiation dose to the patient in comparison to a reference O-arm system without these capabilities.

Simple preoperative radiation safety interventions significantly lower radiation doses during central venous line placement in children

PURPOSE

The purpose of this study was to reduce radiation exposure during pediatric central venous line (CVL) placement by implementing a radiation safety process including a radiation safety briefing and a job-instruction model with a preradiation time-out.

METHODS

We reviewed records of all patients under 21 who underwent CVL placement in the operating room covering 22 months before the intervention through 10 months after 2013-2016. The intervention consisted of a radiation safety briefing by the surgeon to the intraoperative staff before each case and a radiation safety time-out. We measured and analyzed the dose area product (DAP), total radiation time pre- and postintervention, and the use of postprocedural chest radiograph.

RESULTS

100 patients with valid DAP measurements were identified for analysis (59 preintervention, 41 postintervention). Following implementation of the radiation safety process, there was a 79% decrease in median DAP (61.4 vs 13.1 rad*cm², P < 0.001) and a 73% decrease in the median radiation time (28 vs 7.6 s, P < 0.001). Additionally, there was a significant reduction in use of confirmatory CXR (95% vs 15%, P < 0.01).

CONCLUSION

A preoperative radiation safety briefing and a radiation safety time-out supported by a job-instruction model were effective in significantly lowering the absorbed doses of radiation in children undergoing CVL insertion.

TYPE OF STUDY

Case-control study.

LEVEL OF EVIDENCE

Level III.

[Radiation protection measures: Implications on the design of neurosurgery operating rooms]

OBJECTIVE

To describe pros and cons of some radiation protection measures and the implications on the design of a neurosurgery operating room.

MATERIAL AND METHODS

Concurring with the acquisition and use of an O-arm device, a structural remodeling of our neurosurgery operating room was carried out. The theater was enlarged, the shielding was reinforced and a foldable leaded screen was installed inside the operating room. Radiation doses were measured in front of and behind the screen.

RESULTS

The screen provides whole-body radiation protection for all the personnel inside the theater (effective dose <5μSv at 2,5 m from the gantry per O-arm exploration; 0,0μSv received behind the screen per O-arm exploration; and undetectable cumulative annual radiation dose behind the screen), obviates the need for leaded aprons and personal dosimeters, and minimizes the circulation of personnel. Enlarging the size of the operating room allows storing the equipment inside and minimizes the risk of collision and contamination. Rectangular rooms provide greater distance from the source of radiation.

CONCLUSION

Floor, ceiling and walls shielding, a rectangular-shaped and large enough theater, the presence of a foldable leaded screen, and the security systems precluding an unexpected irruption into the operating room during irradiation are relevant issues to consider when designing a neurosurgery operating theater.