Safety of endoscopic retrograde cholangiopancreatography in pregnancy: Fluoroscopy time and fetal exposure, does it matter?

AIM: To estimate the fetal radiation exposure using thermoluminescent dosimeters (TLD's) in pregnant patients undergoing endoscopic retrograde cholangiopancreatography (ERCP) and assess its relevance. METHODS: Data on thirty-five therapeutic ERCPs conducted in pregnant patients from 2001 to 2009 were retrieved from a prospective database. Techniques to minimize fluoroscopy time were implemented and the fluoroscopy times captured. TLD's were placed on the mother to estimate the fetal radiation exposure and the results were compared to the maximum allowed dose of radiation to the fetus [0.005 gray (Gy)]. Obstetrics consultations were obtained and the fetus was monitored before and after the ERCP. Fluoroscopy wasperformed at 75 kVp. ERCP was performed with the patients supine by dedicated biliary endoscopists performing more than 500 cases a year. RESULTS: A total of 35 pregnant patients underwent ERCP and biliary sphincterotomy (14 in first trimester, 11 in second trimester, and 10 in third trimester). Mean maternal age was 25 years (range 16-37 years) and mean gestational age was 18.9 wk (range 4-35 wk). Mean fluoroscopy time was 0.15 min (range 0-1 min). For 23 women, the estimated fetal radiation exposure was almost negligible (< 0.0001 Gy) while for 8 women, it was within the 0.0001-0.0002 Gy range. Three women had an estimated fetal radiation exposure between 0.0002 and 0.0005 Gy and 1 woman had an estimated fetal radiation exposure greater than 0.0005 Gy. Complications included 2 post-sphincterotomy bleeds, 2 post-ERCP pancreatitis, and 1 fatal acute respiratory distress syndrome. One patient developed cholecystitis 2 d after ERCP. CONCLUSION: ERCP with modified techniques is safe during pregnancy, and estimating the fetal radiation exposure from the fluoroscopy time or measuring it via TLD's is unnecessary.

Fluoroscopy guided percutaneous renal access in prone position

Percutaneous nephrolithotomy is a very commonly done procedure for management of renal calculus disease. Establishing a good access is the first and probably themost crucial step of this procedure. A proper access is the gateway to success. However, this crucial step has the steepest learning curve for, in a fluoroscopy guided access, it involves visualizing a three dimensional anatomy on a two dimensional fluoroscopy screen. This review describes the anatomical basis of the renal access. It provides a literature review of all aspects of percutaneous renal access along with the advances that have taken place in this field over the years. The article describes a technique to determine the site of skin puncture, the angle and depth of puncture using a simple mathematical principle. It also reviews the common problems faced during the process of puncture and dilatation and describes the ways to overcome them. The aim of this article is to provide the reader a step by step guide for percutaneous renal access.

Augmented reality: The use of the PicoLinker smart glasses improves wire insertion under fluoroscopy

AIM To demonstrate the feasibility of the wearable smart glasses, Pico Linker, in guide wire insertion under fluoroscopic guidance. METHODS Under a fluoroscope, a surgeon inserted 3 mm guide wires into plastic femurs from the lateral cortex to the femoral head center while the surgeon did or did not wear Pico Linker, which are wearable smart glasses where the fluoroscopic video was displayed(10 guide wires each). RESULTS The tip apex distance, radiation exposure time and total insertion time were significantly shorter while wearing the Pico Linker smart glasses. CONCLUSION This study indicated that the Pico Linker smart glasses can improve accuracy, reduce radiation exposure time, and reduce total insertion time. This is due to the fact that the Pico Linker smart glasses enable surgeons to keep their eyes on the operation field.

Virtual bronchoscopic navigation without fluoroscopy guidance for peripheral pulmonary lesions in inexperienced pulmonologist

Objective:Fluoroscopy guidance is generally required for endobronchial ultrasonography with guide sheath(EBUS-GS)in peripheral pulmonary lesions(PPLs).Virtual bronchoscopic navigation(VBN)can guide the bronchoscope by creating virtual images of the bronchial route to the lesion.The diagnostic yield and safety profiles of VBN without fluoroscopy for PPLs have not been evaluated in inexperienced pulmonologist performing EBUS-GS.Methods:Between January 2016 and June 2017,consecutive patients with PPLs referred for EBUS-GS at a single cancer center were enrolled.The diagnostic yield as well as safety profiles was retrospectively analyzed,and our preliminary experience was shared.Results:A total of 109 patients with 109 lesions were included,99(90.8%)lesions were visible on EBUS imaging.According to the procedure time needed to locate the lesion on EBUS,24.8%(27/109)were deemed technically difficult procedures;however,no significant relationships were identified between candidate parameters and technically difficult procedures.The overall diagnosis yield was 74.3%(81/109),and the diagnostic yield of malignancy was 83.7%(77/92).Lesions larger than 20 mm[odds ratio(OR),2.758;95%confidence interval(95%CI),1.077-7.062;P=0.034]and probe of within type(OR,3.174;95%CI,1.151-8.757,P=0.026)were independent factors leading to a better diagnostic yield in multivariate analysis.About 30 practice procedures were needed to achieve a stable diagnostic yield,and the proportion of technically difficult procedures decreased and stabilized after 70 practice procedures.Regarding complications,one patient(0.9%)had intraoperative hemorrhage(100 mL)which was managed under endoscopy.Conclusions:VBN without fluoroscopy guidance is still useful and safe for PPLs diagnosis,especially for malignant diseases when performed by pulmonologist without previous experience of EBUS-GS.VBN may simplify the process of lesion positioning and further multi-center randomized studies are warranted.

Fluoroscopy:An essential diagnostic modality in the age of highresolution cross-sectional imaging

The importance of fluoroscopy as an imaging modality has been minimized relative to other cross-sectional modalities,including high-resolution computed tomography(CT),magnetic resonance imaging(MRI)and ultrasound.Fluoroscopy examinations have decreased in clinical practice due to reduced appreciation of its usefulness,insufficient training of residents,fewer staff with adequate expertise,and poor reimbursements relative to other modalities.We revisit and build upon the prior literature and history of this decreased utilization.We then seek to prove continued value,through categorized examples and within multiple subspecialties,wherein fluoroscopy plays an integral part toward clinical diagnoses as well as optimizing patient outcomes.This is particularly true for motility and esophageal disorders,where structure and function with real-time evaluation is essential.We additionally show several post-operative cases where the synergy of fluoroscopy with CT and endoscopy is apparent.The fluoroscopic radiologist also has the unique ability to vary patient positioning,as opposed to traditional CT or MRI,where orthogonal views are employed without positional or temporal changes.We turn attention to the modern era,with synergistic and novel cases demonstrating that fluoroscopy remains instrumental toward achieving a diagnosis alongside other modalities.Our cases stress the need to maintain expertise in fluoroscopy skill,and underline its continued importance in residency training programs.We conclude that fluoroscopy is a relatively inexpensive modality that is often under-appreciated in diagnostic radiology.We suggest that competency in fluoroscopy is crucial for future generations of radiologists to both work with their peers,as well as to aid clinicians in the optimal treatment of patients.

Does the presence of a percutaneous renal access influence fluoroscopy time during percutaneous nephrolithotomy?

Objective:The aim of this study was to assess whether the presence of a preformed percutaneous renal access(PCA)had any effects on fluoroscopy time(FT)during percutaneous nephrolithotomy(PCNL).Methods:After ethics approval was obtained,medical records of all patients who underwent PCNL between 2009 and 2013 at a tertiary stone referral centre were retrospectively reviewed.Patients with and without pre-formed PCA undergoing PCNL were compared.Patients who underwent second-look PCNL and those who had their access inserted by interventional radiology constituted the group with pre-formed PCA.Results:A total of 185 PCNLs were reviewed.The mean patient age was 55.2±1.0 years with mean body mass index(BMI)of 27.8±0.5 kg/m^2 and male gender of 63.8%.The mean stone size was 618.4±47.0 mm^2 with mean Guy’s grade of 2.3±0.7 and mean S.T.O.N.E.score of 7.6±0.1.The mean operative time was 98.7±2.6 min with mean FT of 113.4±4.5 s.The overall stone-free rate was 71.9%with complication rate of 16.2%.When compared with PCNLs without pre-formed PCA,PCNLs with pre-formed PCA were associated with significantly shorter FT(120.6±5.1 vs.77.5±6.7 s;p<0.001)and significantly lower estimated blood loss(EBL)(p=0.01).On multivariate analysis,PCNLs with pre-formed PCA were associated with significantly shorter FT(B.coefficient=-43.2(95%CI:-66.4 to-20);p<0.001)and lower EBL(p=0.02).Conclusion:PCNLs with pre-formed PCA were associated with significantly lower FT and EBL when compared with PCNLs without pre-formed PCA.

Posteroinferior Cerebellar Artery (PICA) Fusiform Aneurysm Ruptured Related with a Pure Arterial Malformation: Case Report and Technical Note (NBCA Embolization under Roadmap-Fluoroscopy)

Background: The pure arterial malformation (PAM) lesion has been recently described as a vascular pathology characterized by the sole presence of coiled, sometimes ectatic, arterial loops. 2% of the fusiform aneurysms are located in the vertebral-posterior inferior cerebellar arteries. Case Presentation: A 60 years old female with subarachnoid hemorrhage was diagnosed with a fusiform aneurysm in the right PICA related with a PAM in the digital subtraction angiography (DSA). With a negative super-selective Wada test, the patient was treated with embolization of the two lesions and the PICA for being in the same arterial territory with adhesive embolic liquid under roadmap fluoroscopy technique. The patient had a satisfactory clinical evolution and no added neurological deficit, so she was discharged 3 days after the treatment. Conclusion: These two vascular lesions located in the same artery are very rare and more in the PICA territory. It is important to make the best decision to treat them because of the potential complications;that’s why the procedure was supported with super-selective Wada test and neuromonitoring of the PICA territory. The injection of the mixture of NBCA and Lipiodol® under roadmap fluoroscopy is very safe.

The Role of Artificial Intelligence (AI) in Radiation Protection of Computed Tomography and Fluoroscopy: A Review

Background: The medical imaging world is currently changing with the introduction of advanced modalities to help with diagnosis. There is then the need for the application of Artificial Intelligence (AI) in areas such as radiation protection to improve the safety as far as radiations are concerned. This review article discusses the principles, some of the challenges of radiation protection and the possible role of Artificial Intelligence (AI) regarding radiation protection in computed tomography and fluoroscopy exams. Methods: A literature search was done using Google Scholar, Science Direct and Pubmed to search for relevant articles concerning the review topic. Results: Some of the challenges identified were outdated and old X-ray machines, lack of QA programs on the machines amongst others. It was discovered that AI could be applied in areas like scan planning and positioning, patient positioning amongst others in CT imaging to reduce radiation doses. With fluoroscopy, an AI enabled system helped in reducing radiation doses by selecting the region of interest of pathology and exposing that region. Conclusion: The application of AI will improve safety and standards of practice in medical imaging.

The optimal stent pusher position to achieve successful ureteral stent insertion under fluoroscopic guidance

Objective: To examine factors to predict the optimal stent pusher position when inserting ureteral stents under fluoroscopy.Methods: We retrospectively reviewed 327 patients who underwent ureteral stent insertion. We considered the pubic bone as a useful anatomical landmark to insert ureteral stents under fluoroscopic guidance. Thus, we categorized patients into three groups (proximal, middle, and distal groups) according to the position of the radiopaque tip of the push catheter when inserting the ureteral stent. Success was defined as a completely curled ureteral stent tail. We compared stent insertion success rates among the three groups. A multivariate analysis was performed to identify the factors affecting stent insertion success.Results: In men, 36 (63.2%) cases were deemed successful in the proximal group compared with 40 (80.0%) cases in the middle group and 12 (20.7%) cases in the distal group (p<0.001). In women, 26 (45.6%) cases were deemed successful in the proximal group compared with 54 (98.2%) cases in the middle group and 38 (76.0%) cases in the distal group (p<0.001). With the multivariate analysis, the stent pusher position was the most significant factor influencing successful stent insertion (men: odds ratio 6.00, 95% confidence interval 2.66-13.51, p<0.001;women: odds ratio 37.80, 95% confidence interval 4.94-289.22, p<0.001).Conclusion: The position of the stent pusher affects stent insertion success. The middle of the pubic symphysis is the optimal position for the radiopaque tip of the pusher when inserting ureteral stents under fluoroscopic guidance.

Accuracy and complications of posterior C2 screw fixation using intraoperative three-dimensional fluoroscopy-based navigation

Background The peculiar and highly variable C2 anatomy can make screw fixation more challenging and prone to potential vertebral artery or neurologic injury. Conventional C-arm fluoroscopy has several drawbacks. The aim of this research was to evaluate the accuracy of posterior C2 screw fixation using intraoperative three-dimensional fluoroscopy- based navigation （ITFN） and assess the perioperative complication rate related to screw placement. Methods A retrospective review identified patients who underwent operative management with C2 instruments using ITFN at our hospital between January 2006 and December 2012. Clinical data were obtained from medical records and final screw positions were graded according to a modified classification of Gertzbein and Robbins. Grade A and B screws were considered well positioned. Results The study included 99 patients （53 males and 46 females） who underwent posterior C2 screw fixation using ITFN. The mean Japan Orthopedic Association score improved from （6.7±1.9） points before surgery to （12.5±2.7） points at 6-month follow-up （z= ＋8.628, P 〈0.01）. The mean visual analogue scale improved from （4.1±1.2） points before surgery to （0.7±0.9） points at 6-month follow-up, with an improvement of 83.7% （z= 8.638, P 〈 0.01）. Of the 196 screws analyzed using computed tomography and chart review, 126 transarticular, 64 pedicle, and 6 pars screws were placed with 82.5% （104/126）, 89.1% （57/64）, and 100% （6/6） accuracy （grade A）, respectively; 98.5% （193/196） of screws were grade A or B （grade C, 1.5% （3/196））, and no neurologic injuries occurred. In normal C2 cases, 93 transarticulars and 47 pedicles were placed with high accuracy rates of 90.3% （84/93） and 93.6% （44/47） （grade A）, respectively. However, in cases with C2 deformity, 33 transarticular, 17 pedicle, and 6 pars screws were placed with only 60.6% （20/33）, 76.5% （13/17）, and 100% （6/6） accuracy （grade A）, respectively. Conclusion ITFN is a safe, accurate, and effective tool for posterior C2 fixation. Chin Med J 2014;127 （14）： 2654-2658

0Optimized Fluoroscopy Setting and Appropriate Project Position Can Reduce X-ray Radiation Doses Rates during Electrophysiology Procedures

Background：Nonfluoroscopic three-dimensional electroanatomical system is widely used nowadays,but X-ray remains indispensable for complex electrophysiology procedures.This study aimed to evaluate the value of optimized parameter setting and different projection position to reduce X-ray radiation dose rates.Methods：From June 2013 to October 2013,105 consecutive patients who underwent complex ablation were enrolled in the study.After the ablation,the radiation dose rates were measured by two different settings （default setting and optimized setting） with three projection positions （posteroanterior [PA] projection;left anterior oblique [LAO] 30° projection;and LAO 45° projection）.The parameter of preset voltage,pulse width,critical voltage,peak voltage,noise reduction,edge enhancement,pulse rate,and dose per frame was modified in the optimized setting.Results：The optimized setting reduced radiation dose rates by 87.5％ （1.7 Gy/min vs.13.6 Gy/min,P ＜ 0.001） in PA,87.3％ （2.5 Gy/min vs.19.7 Gy/min,P＜0.001） in LAO 30°,85.9％ （3.1 Gy/min vs.22.1 Gy/min,P ＜ 0.001） in LAO 45°.Increase the angle of projection position will increase the radiation dose rate.Conclusions：We can reduce X-ray radiation dose rates by adjusting the parameter setting of X-ray system.Avoiding oblique projection of large angle is another way to reduce X-ray radiation dose rates.

Three-dimensional Fluoroscopy-based Navigation for the Pedicle Screw Placement in Patients with Primary Invasive Spinal Tumors

Background：Although pedicle screw placement （PSP） is a well-established technique for spine surgery,the treatment of patients with primary invasive spinal tumor （PIST） has high surgical risks secondary to destroyed pedicles.Intraoperative three-dimensional fluoroscopy-based navigation （ITFN） system permits safe and accurate instrumentation of the spine with the advantage of obtaining intraoperative real-time three-dimensional images and automatic registration.The aim of this study is to evaluate the feasibility and accuracy of PSP using ITFN system for patients afflicted with PIST in the thoracic spine.Methods：Fifty-one patients diagnosed with PISTs were retrospectively analyzed,and 157 pedicles screws were implanted in 23 patients using the free-hand technique （free-hand group） and 197 pedicle screws were implanted in 28 patients using the ITFN system （ITFN group）.Modified classification of Gertzbein and Robbins was used to evaluate the accuracy of PSP,and McCormick classification was applied for assessment of neurological function.Demographic data and factors affecting accuracy of screw insertion were compared using independent t-test while comparison of accuracy of screw insertion between the two groups was analyzed with Chi-square test.Results：Of 51 patients,39 demonstrated improved neurological status and the other 12 patients reported that symptoms remained the same.In the free-hand group,145 screws （92.4%） were Grade Ⅰ,9 screws （5.7%） were Grade Ⅱ,and 3 screws （1.9%） were Grade Ⅲ.In the ITFN group,192 screws （97.4%） were Grade Ⅰ,5 screws （2.6%） were Grade Ⅱ,and no Grade Ⅲ screw was detected.Statistical analysis showed that the accuracies of pedicle screws in the two groups are significantly different （χ^2 =4.981,P =0.026）.Conclusions：The treatments of PISTs include total tumor resection and reconstruction of spine stability.The ITFN system provides a high accuracy of pedicle screw placement.

Congenital left ventricular diverticulum, a rare chest fluoroscopy finding： a case report

Congenital left ventricular diverticulum is a very rare cardiac abnormality and it is not completely understood about its etiology, clinical manifestation, diagnosis, treatment and prognosis. This article presents a case of large congenital diverticulum of the left ventricle. The clinical manifestation included paroxysmal supraventricular tachycardia. The diagnosis was made by chest fluoroscopy observation and confirmed by 64-slice CT-angiography. The arrhythmia alleviated instead of antiarrhythmic drugs but by radiofrequency catheter ablation. Due to the rapid growth of the diverticulum, the patient underwent surgical resection finally. Owing to the fatal risks, clinicians should improve the understanding of this disease by deeply studving more cases, in order to standardize the treatment.

Effect of fluoroscopy frame rate on radiation exposure and in-hospital outcomes in cardiovascular implantable electronic device implantation procedures

Objective:To assess the radiation exposure in cardiovascular implantable electronic device(CIED)implantation procedures,the effect of fluoroscopy frame rate on various radiation exposure indices,and in-hospital outcomes.Methods:Data of CIED implantation procedures from September 2015 to December 2019 of all the CIED implantation procedures performed at our institute were retrospectively analyzed.The procedural data were divided into two groups:a)pre-group:procedures that were performed under fluoroscopy frame rate of 7.5 frames per second(fps);b)post-group:procedures that were performed under fluoroscopy frame rate of 3.75 fps.We compared procedure time,fluoroscopy time,Kerma air product,effective dose,and in-hospital outcomes between the two groups.Results:A total of 2,225 procedures were included in the analysis with mean age of(62±15)years.The procedures consisted of the implantation of single-chamber(n=1,436),double chamber(n=656),and biventricular devices(n=133).Procedure time and radiation indices showed a significant reduction over the study period(P<0.001).Reduction in the fluoroscopy frame rate was associated with a significant reduction in radiation exposure indices(P<0.001).In-hospital outcomes did not differ between the two groups.Conclusions:Reduction in the fluoroscopy frame rate from 7.5 to 3.75 fps significantly decreased the radiation exposure in CIED implantation procedures.A framerate lower than 3.75 fps should be the default setting during such procedures.

A pilot clinical study of developing an External Assist Targeting Device for rapid and precise renal calyx access during percutaneous nephrolithotomy

Objective:To design a device to increase the accuracy of the targeting process and reduce the radiation exposure to both the patients and the medical staff.Methods:We analyzed the inherent problem and designed the External Assist Targeting Device(EATD)to assist in the alignment of needle targeting on the desired renal calyx under fluoroscopic guidance.The EATD was designed to allow rapid and precise access to calyces at all angles,with a simple two-step puncture protocol developed for puncturing a target renal calyx.We then tested the device in a pilot human trial with four patients.Results:In experiments with phantom models,the time for successful targeting was reduced by 31%using the device.The mean fluoroscopic time was reduced by 40%.In initial human trial,the puncture time was shortened by 66%and the radiation dose was decreased by 65%compared to free-hand technique.No complication was observed during the trial.Conclusion:The EATD was found to be cost effective,portable,simple to set up,and safe to operate for assisting in the percutaneous nephrolithotomy procedures.Our preliminary tests showed high degree of accuracy in gaining precise access to a targeted renal calyx with much shorter time and lesser radiation dose.The EATD also has the potential to be used to access other organs with precision under fluoroscopic guidance.

Minimally invasive surgeries for insertional Achilles tendinopathy:A commentary review

Studies of minimally invasive surgery for insertional Achilles tendinopathy are limited.To establish this surgery,the following techniques must be minimally invasive:Exostosis resection at the Achilles tendon insertion,debridement of degenerated Achilles tendon,reattachment using anchors or augmentation using flexor hallucis longus(FHL)tendon transfer,and excision of the posterosuperior calcaneal prominence.Studies on these four perspectives were reviewed to establish minimally invasive surgery for insertional Achilles tendinopathy.Techniques for exostosis resection were demonstrated in one case study,where blunt dissection around the exostosis was performed,and the exostosis was resected using an abrasion burr under fluoroscopic guidance.Techniques for debridement of degenerated Achilles tendon were demonstrated in the same case study,where the space left after resection of the exostosis was used as an endoscopic working space,and the degenerated Achilles tendon and intra-tendinous calcification were debrided endoscopically.Achilles tendon reattachment techniques using suture anchors have been demonstrated in several studies.However,there are no studies on FHL tendon transfer techniques for Achilles tendon reattachment.In contrast,endoscopic posterosuperior calcaneal prominence resection is already established.Additionally,studies on ultrasound-guided surgeries and percutaneous dorsal wedge calcaneal osteotomy as minimally invasive surgery were reviewed.

Influence of Previous Abdominal and Pelvic Surgeries on Uterine Artery Embolization

Objective: To assess the influence of previous abdominal and pelvic surgeries on uterine artery embolization (UAE). We hypothesize that the formation of postoperative adhesions can impose technical difficulties for UAE, resulting in longer fluoroscopy time and less reduction of uterus and largest tumor volumes after the procedure. Methods: We retrospectively reviewed the medical records of 122 consecutive patients who underwent uterine artery embolization for the treatment of uterine fibroids in our department. Patients were divided into two groups according to the presence or absence of previous abdominal or pelvic surgery. Fluoroscopy time, change in symptoms, and volume variation of uterus and largest tumor were compared between groups. Results: Forty-seven patients underwent abdominopelvic surgery before UAE (Group 1) and 75 did not (Group 2). Median (IQR) fluoroscopy time was 22 minutes (IQR: 18 - 26.4) for Group 1, and 23.3 minutes (IQR: 19.05 - 28.25) for Group 2. No difference was found between the groups (P = 0.17). Regarding the results after UAE, neither the change in symptoms (P = 0.30) nor the volume variation for uterus (P = 0.41) and largest fibroid (P = 0.18) showed significant difference. Conclusions: In this study, previous abdominopelvic surgeries had no significant influence on fluoroscopy time, and overall outcomes of uterine artery embolization.

Simple lateral elbow dislocation:A case report

BACKGROUND Simple lateral elbow dislocation(SLED)is a rare type of elbow dislocation;however,its treatment may be complicated by accompanying soft tissue or neurovascular damage.Herein,we report a rare case of SLED managed secondarily with open reduction and soft tissue repair following failure of closed reduction.CASE SUMMARY A 67-year-old woman suffered SLED after falling on her outstretched left hand with her elbow extended.She developed pain,swelling,and movement restriction in the elbow;there were no neurovascular symptoms,except for numbness in the 4th and 5th digits.Radiologic investigation confirmed the SLED,and a closed reduction under anesthesia was performed.The follow-up radiographs at 1-wk revealed failure of reduction;accordingly,open reduction with lateral collateral ligament and common extensor origin repair were carried out.The patient regained full elbow range of motion by six weeks.CONCLUSION Adequate concentric reduction for SLED,conservatively or surgically,reduces complications and provides a more functional joint.

Techniques and accuracy of thoracolumbar pedicle screw placement

Pedicle screw instrumentation has been used to stabilize the thoracolumbar spine for several decades. Although pedicle screws were originally placed via a freehand technique, there has been a movement in favor of pedicle screw placement with the aid of imaging. Such assistive techniques include fluoroscopy guidance and stereotactic navigation. Imaging has the benefit of increased visualization of a pedicle's trajectory, but can result in increased morbidity associated with radiation exposure, increased time expenditure, and possible workflow interruption. Many institutions have reported high accuracies with each of these three core techniques. However, due to differing definitions of accuracy and varying radiographic analyses, it is extremely difficult to compare studies side-by-side to determine which techniques are superior. From the literature, it can be concluded that pedicles of vertebrae within the mid-thoracic spine and vertebrae that have altered morphology due to scoliosis or other deformities are the most difficult to cannulate. Thus, spine surgeons would benefit the most from using assistive technologies in these circumstances. All other pedicles in thethoracolumbar spine should theoretically be cannulated with ease via a free-hand technique, given appropriate training and experience. Despite these global recommendations, appropriate techniques must be chosen at the surgeon's discretion. Such determinations should be based on the surgeon's experience and the specific pathology that will be treated.

Radiation dose to patients during endoscopic retrograde cholangiopancreatography

Endoscopic retrograde cholangiopancreatography (ERCP) is an important tool for the diagnosis and treatment of the hepatobiliary system. The use of fluoroscopy to aid ERCP places both the patient and the endoscopy staff at risk of radiation-induced injury. Radiation dose to patients during ERCP depends on many factors, and the endoscopist cannot control some variables, such as patient size, procedure type, or fluoroscopic equipment used. Previous reports have demonstrated a linear relationship between radiation dose and fluoroscopy duration. When fluoroscopy is used to assist ERCP, the shortest fluoroscopy time possible is recommended. Pulsed fluoroscopy and monitoring the length of fluoroscopy have been suggested for an overall reduction in both radiation exposure and fluoroscopy times. Fluoroscopy time is shorter when ERCP is performed by an endoscopist who has many years experience of performing ERCP and carried out a large number of ERCPs in the preceding year. In general, radiation exposure is greater during therapeutic ERCP than during diagnostic ERCP. Factors associated with prolonged fluoroscopy have been delineated recently, but these have not been validated.