Accuracy study of a binocular-stereo-vision-based navigation robot for minimally invasive interventional procedures

BACKGROUND Medical robot is a promising surgical tool,but no specific one has been designed for interventional treatment of chronic pain.We developed a computed tomography-image based navigation robot using a new registration method with binocular vision.This kind of robot is appropriate for minimal invasive interventional procedures and easy to operate.The feasibility,accuracy and stability of this new robot need to be tested.AIM To assess quantitatively the feasibility,accuracy and stability of the binocularstereo-vision-based navigation robot for minimally invasive interventional procedures.METHODS A box model was designed for assessing the accuracy for targets at different distances.Nine(three sets)lead spheres were embedded in the model as puncture goals.The entry-to-target distances were set 50 mm(short-distance),100 mm(medium-distance)and 150 mm(long-distance).Puncture procedure was repeated three times for each goal.The Euclidian error of each puncture was calculated and statistically analyzed.Three head phantoms were used to explore the clinical feasibility and stability.Three independent operators conducted foramen ovale placement on head phantoms(both sides)by freehand or under the guidance of robot(18 punctures with each method).The operation time,adjustment time and one-time success rate were recorded,and the two guidancemethods were compared.RESULTS On the box model,the mean puncture errors of navigation robot were 1.7±0.9 mm for the short-distance target,2.4±1.0 mm for the moderate target and 4.4±1.4 mm for the long-distance target.On the head phantom,no obvious differences in operation time and adjustment time were found among the three performers(P>0.05).The median adjustment time was significantly less under the guidance of the robot than under free hand.The one-time success rate was significantly higher with the robot(P<0.05).There was no obvious difference in operation time between the two methods(P>0.05).CONCLUSION In the laboratory environment,accuracy of binocular-stereo-vision-based navigation robot is acceptable for target at 100 mm depth or less.Compared with freehand,foramen ovale placement accuracy can be improved with robot guidance.

Endoscopic ultrasound-guided biliary drainage after failed endoscopic retrograde cholangiopancreatography: The road is open for almighty biliopancreatic endoscopists!

Commentary on the article written and published by Peng et al,investigating the role of endoscopic ultrasound(EUS)-guided biliary drainage for palliation of malignant biliary obstruction after failed endoscopic retrograde cholangiopan-creatography(ERCP).For 40 years endoscopic biliary drainage was synonymous with ERCP,and EUS was used mainly for diagnostic purposes.The advent of therapeutic EUS has revolutionized the field,especially with the development of a novel device such as electrocautery-enhanced lumen-apposing metal stents.Complete biliopancreatic endoscopists with both skills in ERCP and in interven-tional EUS,would be ideally suited to ensure patients the best drainage technique according to each individual situation.

Management of surgical splenorenal shunt-related hepatic myelopathy with endovascular interventional techniques

We present a case with hepatic myelopathy(HM) due to a surgical splenorenal shunt that was successfully treated by endovascular interventional techniques.A 39-year-old man presented with progressive spastic paraparesis of his lower limbs 14 mo after a splenorenal shunt.A portal venogram identified a widened patent splenorenal shunt.We used an occlusion balloon catheter initially to occlude the shunt.Further monitoring of the patient revealed a decrease in his serum ammonia level and an improvement in leg strength.We then used an Amplatzer vascular plug(AVP) to enable closure of the shunt.During the follow up period of 7 mo,the patient experienced significant clinical improvement and normalization of blood ammonia,without any complications.Occlusion of a surgically created splenorenal shunt with AVP represents an alternative therapy to surgery or coil embolization that can help to relieve shunt-induced HM symptoms.

How to duplicate the procedural success of coronary interventions by the radial approach:tips and tricks in the selection and manipulations of guides

In this issue of the Journal of Geriatric Cardiology;Jing et al. showed off their near perfect results of percutaneous coronary interventions (PCI) through transfemoral approach (TFA) and transradial approach (TRA) in the elderly Chinese patients. All patients were older.than 60years of age, with an average of 67.……

Computed tomography-guided transpulmonary radiofrequency ablation for hepatocellular carcinoma located in hepatic dome

AIM： To determine the feasibility of performing computed tomography （CT）-guided transpulmonary radiofrequency ablation （RFA） for hepatocellular carcinoma （HCC） located in the hepatic dome. METHODS： A total of seven patients with HCC comprising seven nodules located in the hepatic dome were treated from April 2004 to December 2004. CTguided transpulmonary RFA was performed using a cool-tip type electrode （Radionics Company） based on a standardized energy protocol. All tumors located in the hepatic dome were not detectable by the usual ultrasound （US） methods. The lesion diameters ranged from 15 to 27 mm. RESULTS： RFA was technically feasible in all the patients. The puncture procedure was performed twice or less and the total average performance time was 40.6 min. Local tumor control was achieved in all the patients. The necrosis diameter ranged from 25 to 35 mm. The mean follow-up period was 9.6 （7-14 mo） mo. There was no local recurrenceat the follow-up points. Pneumothorax requiring pleural drainage was the main complication, which was observed in two of the seven patients （28.6%）. However, it improved with chest drainage tube, and the tube could be removed within 2-3 d. No other major complications were observed.CONCLUSION： CT-guided puncture is useful for the treatment of tumors located in the hepatic dome which are hardly detectable by US, even though pneumothorax sometimes may occur as a complication. In the cases with adhesion in the pleura for which artificial pleural effusion methods are not appropriate, CT-guided RFA is thus considered to be an alternative treatment for HCC located in the hepatic dome.

Detecting hepatic nodules and identifying feeding arteries of hepatocellular carcinoma: efficacy of cone-beam computed tomography in transcatheter arterial chemoembolization

Aim:To evaluate the effectiveness of using cone-beam computed tomography(CBCT)in transcatheter arterial chemoembolization(TACE)to detect hapatocellular carcinoma(HCC)nodules and their feeding arteries.Methods:Twenty-four patients with HCCs who underwent TACE using CBCT in addition to conventional digital subtraction angiography(DSA)were enrolled.After both conventional DSA and CBCT through the hepatic artery were acquired,TACE were performed.The nodules were defined as an HCC when dense accumulation of iodized oil was found within the nodule on CT obtained 2 weeks after the TACE.The number of detected nodules and identified feeding arteries,and their correlations with anatomical locations were assessed.Results:A total of 39 HCC nodules(tumor diameter,7-40 mm;mean,17.4±7.9 mm)were detected.Thirty-one nodules were detected by DSA alone but 8 nodules were additionally detected by adding CBCT to DSA.There were 53 feeding arteries associated with the 39 HCC nodules.Among these arteries,21 were identified by DSA alone;however,47 were identified by combining CBCT with DSA.Additional feeding arteries,especially for the nodules located at the right and caudate lobes,were identified by CBCT.On the other hand,there was no difference in detection of nodules between the anatomical locations by CBCT.Conclusion:The use of CBCT in addition to DSA offers potential for increasing the number of detected nodules,and the number of their feeding arteries at the right and caudate lobes.CBCT might improve the quality of TACE procedure for HCC than DSA alone.