Extracorporeal shockwave lithotripsy in the management of urinary stones: New concepts and techniques to improve outcomes

Objective: Extracorporeal shockwave lithotripsy (SWL) currently plays an important role in the treatment of urinary tract lithiasis. The purpose of this article was to describe new concepts and procedural strategies that would improve results using SWL as a treatment for urolithiasis, thereby achieving better clinical practice.Methods: A systematic review process was carried in PubMed/PMC from January 2003 to March 2023. A narrative synthesis of the most important aspects has been made.Results: The important recommendations for the adequate selection of the candidate patient for treatment with SWL are summarized, as well as the new strategies for a better application of the technique. Aspects about intraoperative position, stone localization and monitoring, analgesic control, machine and energy settings, and measures aiming at reduced risk of complications are described.Conclusion: To achieve the therapeutic goal of efficient stone disintegration without increasing the risk of complications, it is necessary to make an adequate selection of patients and to pay special attention to several important factors in the application of treatment. Technological development in later generation devices will help to improve current SWL results.

Three-dimensional visualization technology for guiding one-step percutaneous transhepatic cholangioscopic lithotripsy for the treatment of complex hepatolithiasis

BACKGROUND Biliary stone disease is a highly prevalent condition and a leading cause of hospitalization worldwide.Hepatolithiasis with associated strictures has high residual and recurrence rates after traditional multisession percutaneous transhepatic cholangioscopic lithotripsy(PTCSL).AIM To study one-step PTCSL using the percutaneous transhepatic one-step biliary fistulation(PTOBF)technique guided by three-dimensional(3D)visualization.METHODS This was a retrospective,single-center study analyzing,140 patients who,between October 2016 and October 2023,underwent one-step PTCSL for hepatolithiasis.The patients were divided into two groups:The 3D-PTOBF group and the PTOBF group.Stone clearance on choledochoscopy,complications,and long-term clearance and recurrence rates were assessed.RESULTS Age,total bilirubin,direct bilirubin,Child-Pugh class,and stone location were similar between the 2 groups,but there was a significant difference in bile duct strictures,with biliary strictures more common in the 3D-PTOBF group(P=0.001).The median follow-up time was 55.0(55.0,512.0)days.The immediate stone clearance ratio(88.6%vs 27.1%,P=0.000)and stricture resolution ratio(97.1%vs 78.6%,P=0.001)in the 3D-PTOBF group were significantly greater than those in the PTOBF group.Postoperative complication(8.6%vs 41.4%,P=0.000)and stone recurrence rates(7.1%vs 38.6%,P=0.000)were significantly lower in the 3D-PTOBF group.CONCLUSION Three-dimensional visualization helps make one-step PTCSL a safe,effective,and promising treatment for patients with complicated primary hepatolithiasis.The perioperative and long-term outcomes are satisfactory for patients with complicated primary hepatolithiasis.This minimally invasive method has the potential to be used as a substitute for hepatobiliary surgery.

Intravascular lithotripsy successfully open recurrent in-stent chronic occlusion lesion combined with circular calcification

Coronary artery calcification is common in elderly,diabetic,and dialysis-dependent patients,poses a great challenge to interventional therapy and significantly increases the risk of complications and poor prognosis.[1]Traditional rotational atherectomy and excimer laser coronary atherectomy are both special treatment techniques for severely calcified lesions,but they are difficult to use in clinical practice due to complicated operations.Intravascular lithotripsy(IVL)is a new way of treating calcified lesion.

Cost-Effectiveness Analysis of Renalof® versus Extracorporeal Shockwave Lithotripsy (ESWL) for the Treatment of Kidney Stones ≤ 1 cm in Nicaragua

Objectives: To assess the efficiency in terms of cost-effectiveness (CE) of oral Renalof® treatment versus extracorporeal shockwave lithotripsy (ESWL) in the treatment of kidney stones ≤ 1 cm in Nicaragua. Methods: A cost-effectiveness economic evaluation was carried out based on the results obtained in the randomised, prospective, observational, single-blind, prospective, phase 2 clinical trial. Cost-effectiveness and the incremental cost-effectiveness ratio (ICER) were calculated. Economic data were obtained from the Economics Department of Clínica Senior in Managua, Nicaragua. The monetary cost was expressed in US dollars (USD). Results: Treatment with Renalof® yielded a CE of $1,323.08/% remission, while ESWL was $9,498.54/% remission. The ICER shows that, in order to achieve a high percentage of kidney stone remission with ESWL, an extra $4,734.70 per patient must be invested. Conclusions: The use of Renalof® is shown to be a more cost-effective option than ESWL. It is recommended for the treatment of kidney stones ≤ 1 cm in size.

The use of an artificial neural network in the evaluation of the extracorporeal shockwave lithotripsy as a treatment of choice for urinary lithiasis

Objective:Artificial neural networks(ANNs)are widely applied in medicine,since they substantially increase the sensitivity and specificity of the diagnosis,classification,and the prognosis of a medical condition.In this study,we constructed an ANN to evaluate several parameters of extracorporeal shockwave lithotripsy(ESWL),such as the outcome and safety of the procedure.Methods:Patients with urinary lithiasis suitable for ESWL treatment were enrolled.An ANN was designed using MATLAB.Medical data were collected from all patients and 12 nodes were used as inputs.Conventional statistical analysis was also performed.Results:Finally,716 patients were included in our study.Univariate analysis revealed that diabetes and hydronephrosis were positively correlated with ESWL complications.Regarding efficacy,univariate analysis revealed that stone location,stone size,the number and density of shockwaves delivered,and the presence of a stent in the ureter were independent factors of the ESWL outcome.This was further confirmed when adjusted for sex and age in a multivariate analysis.The performance of the ANN at the end of the training state reached 98.72%.The four basic ratios(sensitivity,specificity,positive predictive value,and negative predictive value)were calculated for both training and evaluation data sets.The performance of the ANN at the end of the evaluation state was 81.43%.Conclusion:Our ANN achieved high score in predicting the outcome and the side effects of the ESWL treatment for urinary stones.

Gallbladder biliary lithotripsy:A new rationale applied to old treatment

Pure endoscopic treatment of combined cholelithiasis and choledocholithiasis is possible due to the chance to use together both endoscopic retrograde cholangiopancreatography(ERCP)and endoscopic ultrasound(EUS)approaches.This endotherapy permits to treat biliary stones in the main bile duct by standard ERCP and gallbladder stones by EUS-guided cholecystoduodenostomy eventually associated to intracorporeal lithotripsy to achieve optimal results.

Bouveret syndrome masquerading as a gastric mass-unmasked with endoscopic luminal laser lithotripsy:A case report

BACKGROUND Bouveret syndrome,also known as gallstone ileus,is a rare form of gastric outlet obstruction accounting for 1%-3%of cases.This condition is most often reported in females.The diagnosis can be challenging and is often missed due to atypical presentations,which occasionally mimic gastric outlet obstruction symptoms such as nausea,vomiting,loss of appetite and hematemesis.The symptoms vary with stone size.Larger stones are managed with a surgical approach,but this carries increased morbidity and mortality.Over the past decade,the endoscopic approach has emerged as an alternative mode of treatment,but it is generally unsuccessful in the management of larger-sized stones.A literature review revealed cases of successful endoscopic treatment requiring multiple sessions for stone sizes measuring up to about 4.5 cm.Here we present a unique case of an elderly patient with Bouveret syndrome with a 5 cm stone mimicking a gastric mass and causing gastric outlet obstruction,who was successfully managed in a single session using a complete endoscopic approach with laser lithotripsy.CASE SUMMARY An 85-year-old female patient presented with 1-month history of intermittent abdominal pain,vomiting,decreased appetite and weight loss.An abdominal computed tomography showed a 4.5 cm×4.7 cm partially calcified mass at the gastric pylorus causing gastric outlet obstruction.Endoscopy showed an ulcerated fistulous opening and a large 5 cm impacted gallstone in the duodenal bulb.Endoscopic nets and baskets were used in an attempt to remove the stone,but this approach was unsuccessful.Given her advanced age,poor physical condition and underlying comorbidities,she was deemed to be high-risk for surgery.Thus,a minimally invasive approach using endoscopic laser lithotripsy was attempted and successfully treated the stone.Post-procedure,the patient experienced complete resolution of her symptoms with no complications and was able to tolerate her diet.She was subsequently discharged home at 48 h,with an uneventful recovery.CONCLUSION In our paper we describe Bouveret syndrome and highlight its management with a novel endoscopic approach of laser lithotripsy in addition to various other endoscopic approaches available to date and its success rates.

Do available data support the widespread adoption of pancreatoscopy guided-lithotripsy?

Peroral pancreatoscopy(POPS)is a demanding endoscopic procedure that can be used to perform intracanal lithotripsy in obstructing pancreatic stones but the experience is limited.Most stones can be removed successfully by endoscopic retrograde cholangio-pancreatography but patients with large stones require advanced therapeutic approaches,such as extracorporeal shock wave lithotripsy(alone or followed by endoscopic retrograde cholangio-pancreatography),currently the mainstay of treatment.Unfortunately,in about 10%of cases,extracorporeal shock wave lithotripsy can fail;moreover,it is not be available in many institutions.For this subgroup of patients,POPS guided-lithotripsy can play a role and have benefits.The most consistent study concerns a retrospective multicenter analysis that enrolled few patients per center.Considering the epidemiological scenario and the scant volume of skilled endoscopists,POPS must be developed in very few high-volume referral centers with standardized pathways and capable of performing multi-modality treatment.In addition,we could reasonably assume that POPS-guided-lithotripsy should be used as rescue therapy in special situations,identifying the ideal candidate who can achieve the maximum clinical result,and carefully balancing risk/benefits ratio.

Extracorporeal shock wave lithotripsy for pancreatic and large common bile duct stones

Extraction of large pancreatic and common bile duct(CBD)calculi has always challenged the therapeutic endoscopist.Extracorporeal shockwave lithotripsy(ESWL)is an excellent tool for patients with large pancreatic and CBD calculi that are not amenable to routine endotherapy.Pancreatic calculi in the head and body are targeted by ESWL,with an aim to fragment them to<3 mm diameter so that they can be extracted by subsequent endoscopic retrograde cholangio-pancreatography(ERCP).In our experience,complete clearance of the pancreatic duct was achieved in 76% and partial clearance in 17%of 1006 patients.Short-term pain relief with reduction in the number of analgesics ingested was seen in 84%of these patients.For large CBD calculi,a nasobiliary tube is placed to help target the calculi,as well as bathe the calculi in salinea simple maneuver which helps to facilitate fragmenta-tion.The aim is to fragment calculi to<5 mm size and clear the same during ERCP.Complete clearance of the CBD was achieved in 84.4%of and partial clearance in 12.3%of 283 patients.More than 90%of the patients with pancreatic and biliary calculi needed three or fewer sessions of ESWL with 5000 shocks being de-livered at each session.The use of epidural anesthesia helped in reducing patient movement.This,together with the better focus achieved with newer third-gen-eration lithotripters,prevents collateral tissue damage and minimizes the complications.Complications in our experience with nearly 1300 patients were minimal,and no extension of hospital stay was required.Similar rates of clearance of pancreatic and biliary calculi with minimal adverse effects have been reported from the centers where ESWL is performed regularly.In view of its high efficiency,non-invasive nature and low complication rates,ESWL can be offered as the first-line therapy for selected patients with large pancreatic and CBD calculi.

Prevention strategies for ureteral stricture following ureteroscopic lithotripsy

Ureteral stricture formation after ureteroscopic lithotripsy is a late complication that can lead to hydronephrosis and a subsequent risk of renal deterioration.The specific incidence is unknown,and the mechanism of stricture formation has not been completely explained.In this review,we summarize the current evidence regarding the incidence of this condition and discuss its pathogenesis.We then list preventive strategies to reduce the morbidity of ureteral strictures。

Extracorporeal shock-wave versus pneumatic ureteroscopic lithotripsy in treatment of lower ureteral calculi

Aim: To compare the efficacy and complications of extracorporeal shock-wave lithotripsy (SWL) and pneumatic ureteroscopic lithotripsy (URS) in the treatment of lower ureteral calculi. Methods: From August 1997 to June 1999, 210 patients with calculi in the distal third of the ureter were treated with SWL and the other 180 with URS. The stones were fragmented with either HB-ESWL-V lithotripter or JML-93 pneumatic lithotripter through Wolf 7.5～9.0 Fr ureteroscope. The outcome was assessed in terms of stone clearance rate, re-treatment rate and complication incidence. Results: The stone clearance rate was 78.1% with SWL and 93.3 % with URS (P<0.05). SWL had a re-treatment rate of 11.9 %, vs 2.2 % in the URS group (P<.05). URS caused ureteral perforation in 3.3% of patients, while it was 0 with SWL (P<0.05). The differences in the incidence of other complications such as infection and stricture between the two groups were insignificant. Conclusion: Though the selection of these two options depends on equipments available and the expertise of the operator, we recommend URS as the optimal treatment for distal ureteral calculi. (Asian J Andro12002 Dec, 4: 303-305)

Epidural anesthesia is effective for extracorporeal shock wave lithotripsy of pancreatic and biliary calculi

AIM: To evaluate the efficacy of thoracic epidural analgesia for extracorporeal shock wave lithotripsy (ESWL). METHODS: ESWL is an effective, non-invasive technique for the treatment of difficult pancreatic and large bile duct calculi. The procedure is often painful and requires large doses of analgesics. Many different anesthetic techniques have been used. Patients with either large bile duct calculi or pancreatic duct calculi which could not be extracted by routine endoscopic methods were selected. Thoracic epidural anesthesia (TEA) was routinely used in all the subjects unless contraindicated. Bupivacaine 0.25% with or without clonidine was used to block the segments D6 to D12. The dose was calculated depending on the age, height and weight of the patient. It was usually 1-2 mL per segment blocked.RESULTS: Ninety eight percent of the 1509 patients underwent ESWL under TEA. The subjects selected were within American Society of Anesthesiologists grade Ⅰ to Ⅲ. ESWL using EA permitted successful elimination of bile duct or pancreatic calculi with minimal morbidity. The procedure time was shorter in patients with TEA than in those who underwent ESWL under total intravenous anesthesia. CONCLUSION: Almost all patients undergoing ESWL with EA had effective blocks with a single catheter insertion and local anesthetic injection.

Management hepatolithiasis with operative choledochoscopic FREDDY laser lithotripsy combined with or without hepatectomy

BACKGROUND: Hepatolithiasis is very common in East Asia. It is benign in nature, but has a high recurrence rate. It is likely to lead to biliary cirrhosis and increase the risk of cholangiocarcinoma. Hence, the treatment of hepatolithiasis is difficult but vital. In this report, we present a novel approach to manage hepatolithiasis using the choledochoscopic Frequency-Doubled Double pulse Nd:YAG (FREDDY) laser lithotripsy combined with or without hepatectomy. METHODS: Between July 2009 and October 2012, 45 patients underwent choledochoscopic FREDDY laser lithotripsy combined with or without hepatectomy (laser lithotripsy group). Fortyeight patients underwent a traditional operation (traditional method group) from January 2009 to June 2009. Comparative analysis was made of demographic and clinical characteristics of the two groups. RESULTS: The final stone clearance rate of the laser lithotripsy group was 93.3%, whereas that of the traditional method group was 85.4% (P=0.22). In the laser lithotripsy group, 2 patients experienced hemobilia and 3 patients had acute cholangitis. In the traditional method group, 3 patients had intraoperative hemorrhage, 1 patient had bile leakage, 6 patients had acute cholangitis, and 1 patient died of liver failure. Moreover, the operative time in the traditional method group was significantly longer than that in the laser lithotripsy group (P=0.01). The mean hospital stay of the patients in the traditional method group was longer than that in the laser lithotripsy group (9.8 vs8.2 days, P=0.17). Recurrent intrahepatic bile duct stones were not found during the follow-up period in the two groups. CONCLUSION: Operative choledochoscopic FREDDY laser lithotripsy combined with or without hepatectomy may be an effective and safe treatment for hepatolithiasis.

Outcome of a session of extracorporeal shock wave lithotripsy before endoscopic retrograde cholangiopancreatography for problematic and large common bile duct stones

AIM To compare the efficacy of a session of extracorporeal shock wave lithotripsy(ESWL) before endoscopic retrograde cholangiopancreatography(ERCP) vs ERCP only for problematic and large common bile duct(CBD) stones.METHODS Adult patients with CBD stones for whom initial ERCP was unsuccessful because of the large size of CBD stones were identified. The patients were randomized into two groups,an "ESWL + ERCP group" and an "ERCP-only" group. For ESWL + ERCP cases,ESWL was performed prior to ERCP. Clearance of the CBD,complications related to the ESWL/ERCP procedure,frequency of mechanical lithotripsy use and duration of the ERCP procedure were evaluated in both groups.RESULTS There was no significant difference in baseline characteristics between the two groups. A session of ESWL before ERCP compared with ERCP only resulted in similar outcomes in terms of successful stone removal within the first treatment session(74.2% vs 71.0%,P = 0.135),but a higher clearance rate within the second treatment session(84.4% vs 51.6%,P = 0.018) and total stone clearance(96.0% vs 86.0%,P = 0.029). Moreover,ESWL prior to ERCP not only reduced ERCP procedure time(43 ± 21 min vs 59 ± 28 min,P = 0.034) and the rate of mechanical lithotripsy use(20% vs 30%,P = 0.025),but also raised the clearance rate of extremely large stones(80.0% vs 40.0%,P = 0.016). Post-ERCP complications were similar for the two groups.CONCLUSION Based on the higher rate of successful stone removal and minimal complications,ESWL prior to ERCP appears to be a safe and effective treatment for the endoscopic removal of problematic and large CBD stones.

Outcome of simple use of mechanical lithotripsy of difficult common bile duct stones

AIM: The usual bile duct stone may be removed by means of Dormia basket or balloon catheter, and results are quite good. However, the degree of difficulty is increased when stones are larger. Studies on the subject reported many cases where mechanical lithotripsy is combined with a second technique, e.g. electrohydraulic lithotripsy (EHL), where stones are crushed using baby-mother scope electric shock. The extracorporeal shock-wave lithotripsy (ESWL) or laser lithotripsy also yields an excellent success rate of greater than 90%. However, the equipment for these techniques are very expensive; hence we opted for the simple mechanical lithotripsy and evaluated its performance. METHODS: During the period from August 1996 to December 2002, Mackay Memorial Hospital treated 304 patients suffering from difficult bile duct stones (stone>1.5 cm or stones that could not be removed by the ordinary Dormia basket or balloon catheter). These patients underwent endoscopic papillotomy (EPT) procedure, and stones were removed by means of the Olympus BML-4Q lithotripsy. A follow-up was conducted on the post-treatment conditions and complications of the patients. RESULTS: Out of the 304 patients, bile duct stones were successfully removed from 272 patients, a success rate of about 90%. The procedure failed in 32 patients, for whom surgery was needed. Out of the 272 successfully treated patients, 8 developed cholangitis, 21 developed pancreatitis, and 10 patients had delayed bleeding, and no patient died. Among these 272 successful removal cases, successful bile duct stone removal was achieved after the first lithotripsy in 211 patients, whereas 61 patients underwent multiple sessions of lithotripsy. As for the 61 patients that underwent multiple sessions of mechanical lithotripsy, 6 (9.8%) had post-procedure cholangitis, 12 (19.6%) had pancreatitis, and 9 patients (14.7%) had delayed bleeding. Compared with the 211 patients undergoing a single session of mechanical lithotripsy, 3 (1.4%) had cholangitis, 1 (0.4%) had delayed bleeding, and 7 patients (3.3%) had pancreatitis. Statistical deviation was present in post-procedure cholangitis, delayed bleeding, and pancreatitis of both groups. CONCLUSION: Mechanical bile stone lithotripsy on difficult bile duct stones could produce around 90% successful rate. Moreover, complications are minimal. This finding further confirms the significance of mechanical lithotripsy in the treatment of patients with difficult bile duct stones.

Appropriate kidney stone size for ureteroscopic lithotripsy:When to switch to a percutaneous approach

Flexible ureteroscopy(f URS) has become a more effective and safer treatment for whole upper urinary tract stones. Percutaneous nephrolithotomy(PNL) is currently the first-line recommended treatment for large kidney stones ≥ 20 mm and it has an excellent stone-free rate for large kidney stones. However, its invasiveness is not negligible considering its major complication rates. Staged f URS is a practical treatmentfor such large kidney stones because f URS has a minimal blood transfusion risk, short hospitalization and few restrictions on daily routines. However, as the stone size becomes larger, the stone-free rate decreases, and the number of operations required increases. Therefore, in our opinion, staged f URS is a practical option for kidney stones 20 to 40 mm. Miniaturized PNL combined with f URS should be considered to be a preferred option for stones larger than 40 mm. Moreover, URS is an effective treatment for multiple upper urinary tract stones. Especially for patients with a stone burden < 20 mm, URS is a favorable option that promises a high stone-free rate after a single session either unilaterally or bilaterally. However, for patients with a stone burden ≥ 20 mm, a staged operation should be considered to achieve stone-free status.

Percutaneous transhepatic cholangioscopy and lithotripsy in treating difficult biliary ductal stones: Two case reports

BACKGROUND Endoscopic retrograde cholangiopancreatography(ERCP) is preferred for managing biliary obstruction in patients with bilio-enteric anastomotic strictures(BEAS) and calculi. In patients whose duodenal anatomy is altered following upper gastrointestinal(UGI) tract surgery, ERCP is technically challenging because the biliary tree becomes difficult to access by per-oral endoscopy.Advanced endoscopic therapies like balloon-enteroscopy or rendevous-ERCP may be considered but are not always feasible. Biliary sepsis and comorbidities may also make these patients poor candidates for surgical management of their biliary obstruction.CASE SUMMARY We present two 70-year-old caucasian patients admitted as emergencies with obstructive cholangitis. Both patients had BEAS associated with calculi that were predominantly extrahepatic in Patient 1 and intrahepatic in Patient 2. Both patients were unsuitable for conventional ERCP due to surgically-altered UGl anatomy. Emergency biliary drainage was by percutaneous transhepatic cholangiography(PTC) in both cases and after 6-weeks' maturation, PTC tracts were dilated to perform percutaneous transhepatic cholangioscopy and lithotripsy(PTCSL) for duct clearance. BEAS were firstly dilated fluoroscopically,and then biliary stones were flushed into the small bowel or basket-retrieved under visualization provided by the percutaneously-inserted video cholangioscope. Lithotripsy was used to fragment impacted calculi, also under visualization by video cholangioscopy. Satisfactory duct clearance was achieved in Patient 1 after one PTCSL procedure, but Patient 2 required a further procedure to clear persisting intrahepatic calculi. Ultimately both patients had successful stone clearance confirmed by check cholangiograms.CONCLUSION PTCSL offers a pragmatic, feasible and safe method for biliary tract clearance when neither ERCP nor surgical exploration is suitable.

Mechanical lithotripsy and/or stenting in management of difficult common bile duct stones

BACKGROUND:Mechanical lithotripsy and/or stent insertion is the alternative therapeutic approach in difficult endoscopic retrograde cholangiopancreatography (ERCP)case.This study was designed to investigate the appropriate treatment for extraction of bile duct stones in difficult cases of ERCP. METHODS:Between 2000 and 2008,744 ERCP procedures were performed in 592 patients with choledocholithiasis in our endoscopy unit.The demographic features,and clinical and laboratory findings were collected from a prospectively held database.Bile duct calculi were extracted by basket and/or balloon catheter following ERCP and sphincterotomy.Patients with retained stones were regarded as difficult cases.These patients were treated with mechanical lithotripsy and those with incomplete clearance of stones underwent stent placement. RESULTS:Two hundred and forty-five patients(41%) were male and 347(59%)were female with a mean age of 58 years(range 19-95 years).Stones were impacted in 27 patients(5%).Stone extraction was performed by basket and/or balloon catheter in 610 ERCP procedures,and lithotripsy was performed in 70 ERCP procedures.Forty- four patients underwent stent insertion,and 20 underwent stent replacement.Morbidity occurred in 39 patients (5%),with no mortality associated with the procedure.Hemorrhage occurred in 9 patients and basket impaction in 4.Mild pancreatitis and cholangitis developed in 12 and 11 patients,respectively. CONCLUSION:Difficult cases of bile duct stones can be treated successfully with lithotripsy,and a stent should be applied when the common bile duct cannot be cleared completely.

Indications and contraindications for shock wave lithotripsy and how to improve outcomes

For over 35 years shock wave lithotripsy has proven to be an effective,safe and truly minimally invasive option for the treatment of nephrolithiasis.Various technical factors as well as patient selection can impact the success of the procedure.We used published work focusing on outcomes of shock wave lithotripsy,risk of complications,and strategies for improving stone fragmentation to create this review.Multiple patient and technical factors have been found to impact success of treatment.Skin to stone distance,stone density and composition,size and location of the stone within the urinary system all influence stone free rates.A slower rate with a gradual increasing voltage,precise targeting,proper coupling will improve stone fragmentation and decrease risk of complications.The selection of appropriate patients through a shared decision making process and attention to the technical factors that improve stone free rates is key to providing an effective treatment and patient satisfaction.

Biliary spontaneous dislodgement spiral stent for patients who underwent mechanical lithotripsy

BACKGROUND The incidence of post-endoscopic retrograde cholangiopancreatography(ERCP)cholangitis(PEC)in patients who underwent mechanical lithotripsy(ML)for large stone removal is high(up to 13.3%).One of the main causes is remaining small fragments or sludge that can impair normal biliary drainage.Endoscopic placement of a nasobiliary tube or a conventional plastic biliary stent has been commonly used under such conditions,but the patient may suffer from significant discomfort after the placement of a nasobiliary tube,while additional endoscopy is required for stent removal.We developed a biliary spontaneous dislodgement spiral stent(BSDSS)to overcome those shortcomings.AIM To evaluate the feasibility,safety,and effectiveness of inserting a BSDSS for patients who underwent ML for large stone removal.METHODS We conducted a single-center,retrospective,cohort study at West China Hospital,Sichuan University.A total of 91 consecutive patients with large biliary stones(≥10 mm)in the common bile duct who underwent ML between November 2017 and July 2018 were included.The 49 eligible patients were divided into the BSDSS group and the nasobiliary tube group.Technical success,post-ERCP adverse events(including PEC,post-ERCP pancreatitis,stone recurrence,BSDSS retention,self-extraction and dislocation of the nasobiliary tube),drainage time,and postoperative stay were measured and compared.RESULTS Twenty-one patients in the BSDSS group and 28 patients in the nasobiliary tube group were included in the analyses.The baseline characteristics and clinical information were similar in the two groups.Insertions of BSDSS and nasobiliary tube were technically successful in all 49 patients.There was no significant difference in the incidence of overall post-ERCP adverse events between the two groups(4.8%in the BSDSS group vs 17.9%in the nasobiliary tube group,P=0.219).The median duration of drainage time(3 d in the BSDSS group vs 4 d in the nasobiliary tube group)and length of postoperative stay(4 d in the BSDSS group vs 5 d in the nasobiliary tube group)also did not differ(P=0.934,and P=0.223,respectively).CONCLUSION Endoscopic placement of a BSDSS appears to be feasible,safe and effective for patients who underwent ML for large stone removal.