Keywords Common bile duct - Extracorporeal shock wave lithotripsy - Main pancreatic duct
Introduction
Between 80% and 90% of common bile duct (CBD) stones can be extracted by sphincterotomy
and stone extraction using a balloon catheter or Dormia basket.[1 ]
[2 ]
[3 ]
[4 ] Mechanical lithotripsy is advocated for stones of a larger diameter, and failure
is generally due to inability to grasp the large stones in the basket.[5 ]
[6 ] In approximately 10% of patients it is not possible to clear the bile duct stones
using the above-mentioned techniques.[7 ]
[8 ] Stones bigger than 15 mm in size are considered as large CBD stones. Only 12% of
these could be extracted by routine endoscopic techniques.[9 ] This is mostly due to a difficult anatomy, large size of the calculus, or impaction
of the stone in the CBD. Balloon dilation of the papilla followed by extraction has
been described as a good option for difficult bile duct stones.[10 ]
[11 ]
[12 ]
[13 ] Alternative therapeutic measures for these difficult stones include electrohydraulic
lithotripsy, intraductal laser lithotripsy, and extracorporeal shock wave lithotripsy.[14 ]
[15 ]
[16 ] Extracorporeal shock wave lithotripsy (ESWL) is a novel technique which uses shock
waves to fragment calculi. This was first used successfully to fragment renal calculi.[17 ] The third generation lithotripter uses electromagnetic generator and focus shock
waves to smaller zones, thus minimizing damage to surrounding soft tissue. First generation
lithotripter was based on electrohydraulic shock wave generator; the shock waves were
focused via an ellipsoid metal water-filled tub in which both the patient and the
generator were submerged. Second generation lithotripters use piezoelectric or electromagnetic
generators as energy source. It is coupled with a focusing device to concentrate shockwaves
on smaller focal zone. Intraductal lasers used for bile duct stones include pulsed
solid-state lasers (q-switched neodymiu YAG, alexandrite, and holmiu YAG lasers) or
flashlamp-pumped pulsed dye lasers (coumarin dye and rhodamine-6G lasers). Single
operator cholangioscopy is the most convenient approach for effective biliary laser
lithotripsy.
Approximately 50% of patients with chronic pancreatitis (CP) have developed pancreatic
stones. Removal of the pancreatic duct stones with ERCP alone is often unsuccessful;
thus, pancreatic extracorporeal shock wave lithotripsy (P-ESWL), an effective and
safe micro minimally invasive method is needed to facilitate stone clearance and improve
the success rate of MPD drainage via ERCP.[18 ] Pancreatic duct stones develop during the natural course of longstanding chronic
pancreatitis and are observed in 50% to 90% of patients during long-term follow-up.[19 ] Majority of pancreatic calculi are radio opaque while a few are radiolucent or mixed.[20 ] Pain remains the commonest and the most distressing of symptoms associated with
CCP. Relief of pain is the most important goal of therapy in patients with CCP. Surgical
decompression of the main pancreatic duct (MPD) with clearance of calculi leads to
relief of pain in most patients.[21 ] Ductal decompression can also be achieved by endoscopic techniques. Endoscopy and
surgery are complimentary forms of therapy for relief of pain in patients with chronic
calcific pancreatitis (CCP) Small pancreatic ductal calculi can be extracted using
a basket after an endoscopic pancreatic sphincterotomy. This technique may not be
successful for large stones in the MPD. The problem can be overcome by fragmenting
the calculi.[22 ] Extracorporeal shock wave lithotripsy (ESWL) is an established modality in the management
of large pancreatic ductal calculi.[23 ] The aim of the present study was to assess the efficacy of ESWL on fragmentation
of large CBD and pancreatic duct stones not amenable to routine endoscopic procedures.
Methods
Study Design
The study was conducted in the department of Gastroenterology at Sheri-Kashmir Institute
of Medical Sciences, from June 2015 to December 2016. It was a prospective study and
involved patients of difficult bile duct and large pancreatic duct calculi. The study
was approved by the institutional ethical committee. All patients of biliary calculi
and pancreatic duct calculi who attended the outpatient department or were admitted
in the hospital were screened. Informed consent was obtained from all patients. The
patients who had difficult biliary calculi or large pancreatic duct calculi on ultrasonography
(USG), MRCP, or ERCP were enrolled in the study to receive ESWL for fragmentation
of calculi and subsequent clearance by ERCP. Inclusion criteria involved all patients
with difficult CBD stones which includes stones (>15 mm diameter); impacted stones
in patients with narrow distal CBD and/or difficult anatomy; and all patients with
large pancreatic duct stones (>5 mm) in head or body region.
All patients were subjected to USG abdomen followed by either MRCP or ERCP. The patients
who had definite stone in CBD and/or common hepatic duct on USG were subjected to
ERCP directly. MRCP was performed in patients who had doubtful calculi or biliary
tree was not properly visualized on USG abdomen. All patients with biliary calculi
on USG abdomen or MRCP were subjected to ERCP. Endoscopic Nasobiliary Drainage Tube
(ENBD) was deployed in the patients with large or difficult CBD stones followed by
ESWL for stone disintegration. The patients who had pancreatic duct stones in head
and body region were taken first for MRCP followed by ESWL for stone disintegration
followed by ERP for main pancreatic duct clearance and/or stent deployment if needed.
ESWL was performed under local anesthesia using epidural catheter. Bupivacaine 0.25%
was used to block the segments D6 to D12. DORNIER COMPACT DELTA II ESWL (Munich, Germany)
machine was used for giving shock waves at the rate of 90/min and per session 4,000
to 5,000 shock waves were given. Number of sessions needed was determined by size,
number, and nature of stones. Usually three to four sessions were needed to crush
the stones. After ESWL patients were taken for ERCP to clear CBD or MPD. PD stent
was deployed if needed and was removed after 3 months. Patients in whom we could not
clear CBD/PD calculi were referred for surgical intervention. Pain relief after clearance
of PD calculi with ESWL was assessed in terms of improvement on visual analog scale
and need for analgesia.
End Points
Evaluate the role of ESWL in the clearance of difficult CBD and large pancreatic duct
calculi.
Evaluate the effect of ESWL on pain management in chronic pancreatitis patients.
Secondary outcome: Identify factors that promote stone fragmentation and assessment
of complications, morbidity, and mortality associated with fragmentation of CBD and
MPD calculi using a third-generation lithotripter.
Statistical Analysis
Data analysis was performed using the IBM (Statistical software USA) SPSS version
22.
Difficult CBD stones were defined as stones that could not be extracted by ERCP with
sphincterotomy, Dormia basket, and/or balloon catheter. Stone fragmentation was defined
as the rupture of stones because of ESWL treatment, as fluoroscopically documented.
CBD/PD clearance was defined as complete stone removal after ESWL sessions followed
by ERCP. Patients who did not achieve CBD/PD clearance after five sessions of ESWL
and endoscopic extraction attempts were considered treatment failures.
Results
A total of 1,284 patients underwent ERCP for either choledocholithiasis or pancreatic
duct calculi during study period. Out of them 61 patients had either large or difficult
bile duct calculi or large pancreatic duct calculi. Forty patients had choledocholithiasis
and were labeled as group A and 21 patients were suffering from chronic calcific pancreatitis
with calculi in MPD and were labeled as group B.
Group A—Choledocholithiasis
This group constituted 40 patients with age range from 22 to 75 years and mean age
of 51.9 ± 17.1 years. Fourteen patients (35%) were males and 26 patients (65%) were
females. Twenty-eight (70%) patients presented with biliary pain followed by nonsuppurative
cholangitis in 8 (20%) patients and suppurative cholangitits in 4 (10%) patients (1 ). CBD diameter ranged from 8 to 30 mm with mean 18.3 mm. Stone number in CBD ranged
from 1 to 4 with 26 patients (65%) who had 1 stone, 8 patients (20%) who had 2 stones,
2 patients (5%) who had 3 stones, and 1 patient (2.5%) who had 4 stones. Mean ESWL
shocks needed were 8295.4 ± 3212. Majority of patients (20 [50%]) needed ESWL shocks
in range of 7,000 to 12,000 and only 1 patient (2%) needed ESWL shocks more than 15,000.
Thirteen patients (32.5%) received shocks in range of 2,000 to 7,000, 19 patients
(47.5%) received ESWL shocks in range of 7,000 to 12,000, 4 patients (10%) received
12,001 to 15,000 shocks, and only 1 patient (2.5%) received more than 15,000 shocks
([Fig. 1 ]). Seventeen patients (42.5%) received 2 sessions, 10 patients (25%) received 1 session,
and 10 patients (25%) received 3 sessions. Dilated CBD was seen in majority of patients,
maximum patients 17 (42.5%) had CBD diameter in range of 16 to 20 mm. CBD was cleared
in 37 patients (92.5%) and only in 3 patients (7.5%) CBD could not be cleared and
all three patients had undergone surgical intervention. We found no statistically
significant correlation between bile duct clearance and age, gender, clinical presentation,
number of stones, size of stones, bile duct diameter, number of ESWL sessions, and
number of shocks.
Fig.1 (Group A-Choledocholithiasis) - Mean ESWL shocks needed were 8295.4±3212. Majority
of patients 20 (50%) needed ESWL shocks in range of 7000-12000 and only 1 patient
(2%) needed ESWL shocks more than 15000.
Complications
Group A: Complication occurred in nine patients (22.5%), echymosis occurred in four
patients (10%), abdominal pain in one patient (2.5%), pancreatitis in one patient
(2.5%), and hemobilia in one patient (2.5%). Majority of patients had only one complication
but two patients developed two complications including hematemesis and echymosis in
first patient and abdominal pain and hemobilia in second patient ([Fig. 2 ]).
Fig. 2 (Group A-Choledocholithiasis) - There was no post procedure complication in 31 patients
(77.5%). Complication occurred in 9 patients (22.5%). Major complication were echymosis
which occurred in 4 patients (10%) abdominal pain in 1 patient (2.5%), pancreatitis
in 1 patient(2.5%), hemobilia in 1 patient (2.5%).
Group B—Chronic Pancreatitis
This group constituted 21 patients with age range from 21 to 55 years and mean age
of 40.76 ± 9.63 years. Out of 21 patients, 5 patients (24%) were males and 16 patients
(76%) were females. Seven patients (33.3%) were diabetic and 14 patients (66.6%) were
nondiabetic. Mean stone size was 7.38 mm ± 3.5 mm. Mean ESWL shocks needed for pancreatic
clearance was 7,903.33 ± 4830 ([Fig. 3 ]). Fourteen patients (66.6%) had multiple MPD stones, three patients (14.2%) had
two stones, and four patients (19%) had one stone. Mean stone size was 7.38 ± 3.51.
Out of 21 patients, 10 patients (47.6%) had stone size in the range of 5 to 10 mm,
6 patients (28.6%) 11 to 15 mm, and 5 patients (23.8%) greater than 15 mm. Out of
21 patients, 7 patients needed 1 ESWL session, 7 patients needed 2 sessions, 6 patients
needed 3 sessions, and only 1 patient needed 5 sessions. Mean ESWL shocks needed for
pancreatic clearance was 7,903.33 ± 4,830. Out of 21 patients 12 patients (57.1%)
needed 2,000 to 7,000 shocks, 5 patients (23.8%) needed 7,001 to 12,000 shocks, 3
patients (14.2%) needed 12,001 to 15,000 shocks, and only 1 patient (4%) needed more
than 15,000 shocks. Eight patients (38.1%) had pancreatic duct diameter 5 to 10 mm,
8 patients (38.1%) had pancreatic duct diameter 11 to 15 mm, and 5 patients (23.8%)
had pancreatic duct diameter greater than 15 mm. Main pancreatic duct was cleared
in all 21 patients (100%) and only 1 patient (4%) developed recurrent stones in main
pancreatic duct after follow-up of 18 months. Six patients (28.5%) had a stricture
in main pancreatic duct on ERCP and all these patients were put on plastic pancreatic
duct stent which was removed after 3 months. 71.4% patients of chronic pancreatitis
had complete pain relief, while 14.2% patients had some improvement in pain and 14.2%
of patients had no relief of pain. In our study we found that there is no statistically
significant correlation between pancreatic duct clearance and age, gender, pancreatic
duct diameter, stone size, stone number, number of ESWL shocks, and number of ESWL
sessions.Complications
Fig. 3 (Group B - Chronic Pancreatitis)- Mean ESWL shocks needed for pancreatic clearance
was 7903.33±4830.
Group B: postprocedure complications occurred in five patients (23.8%) and most common
complication was abdominal pain in two patients (9.5%) followed by echymosis in one
patient (4.7%), bradycardia in one patient (4.7%), and vomiting in one (4.7%) patient
([Fig. 4 ]).
Fig. 4 (Group B - Chronic Pancreatitis) - Post procedure complications occurred in 5 patients
(23.8%) and most common complication was abdominal pain in 2 patients (9.5%) followed
by echymosis in 1 patient (4.7%), bradycardia in 1 patient (4.7%) and vomiting in
1 patient (4.7%).
Discussion
Bile Duct Stones
About 90 to 95% of bile duct stones are amenable to endoscopic extraction after EST
using a Dormia basket or a balloon catheter and eventually mechanical lithotripsy.
For the remainder 5 to 10% of the cases in which the anatomical conditions, size or
location of the stone, do not allow for its removal, techniques have been developed
which allow for the fragmentation through shock waves both internally (using electro
hydraulic lithotripsy or laser) or externally through ESWL. The choice of treatment
technique depends to a large extent on experience and local equipment availability,
since such techniques have all shown equal efficacy. ESWL with subsequent endoscopic
extraction of residual fragments is an established treatment option if other endoscopic
means are not successful. CBD stone fragmentation rates of 71 to 95% have been reported
with ESWL, leading to final duct clearance rates of 70 to 90%. In this study, we are
reporting our 1.5 years’ experience in the treatment with ESWL of 61 patients with
difficult CBD or large pancreatic duct stones conducted from June 2015 to December
2016.
Our results suggest that ESWL is a safe, well-tolerated, and effective technique for
the treatment of difficult bile duct stones. A study conducted by Ellis et al showed
that 69 (83%) of patients achieved complete CBD clearance and 75% of patients required
more than one ESWL sessions.[4 ] Tandan et al recruited 283 patients with CBD calculi and used ESWL with ERCP for
CBD clearance. They achieved complete CBD clearance in 84.4% and partial CBD clearance
in 12.3% of patients.[24 ] We achieved bile duct clearance in 37 patients out of 40 patients with clearance
rate of 92.5%, which is slightly higher as compared with other studies which may be
due to less number of patients or soft nature of stones in our patient population
because increased prevalence of recurrent pyogenic cholangitis in our population.
Out of them 26 patients had 1 stone, 8 patients had 2 stones, 2 patients had 3 stones,
and 1 patient had 4 stones; only in 3 patients, CBD could not be cleared and all 3
patients had undergone surgical intervention. We found no statistically significant
correlation between bile duct clearance and age, gender, presentation, number of stones,
stone size, number of ESWL shocks, number of sessions, and bile duct diameter. In
our study only in 3 patients (7.5%) CBD could not be cleared and all three patients
had undergone surgical intervention because of associated gallstones. Failure rate
of our study was less as compared with other studies which may be due to less number
of patients, good analgesia, and use of third-generation lithotripter.
In our study post procedure complications occurred in 9 patients (22.5%), which is
slightly higher than in other studies. It may be due to less number of patients and
learning curve of the procedure. Majority of our patients had only one complication
but two patients developed two complications including hematemesis and ecchymosis
in first patient and abdominal pain and hemobilia in second patient.
Pancreatic Duct Stones
Zhang et al recruited 12 patients in their study; 75% had complete PD clearance after
ESWL.[19 ] Tandan et al had the largest number of patients with PD calculi. Out of 1,006 patients,
76% had complete PD clearance and 17% had partial PD clearance after ESWL.[24 ] Out of 61 patients enrolled in our study, 21 patients had chronic calcific pancreatitis
with dilated MPD and stones in body and head region. Pancreatic duct clearance was
achieved in all 21 patients with duct clearance rate of 100%, which is higher than
in above-mentioned studies. It may be due to less number of patients in our study
and use of third-generation of lithotripters and use of epidural analgesia in all
patients. In only 1 patient (4%) recurrence of stones occurred and in 6 patients (28.5%)
there was a stricture in main pancreatic duct on ERCP and all these patients were
put on pancreatic duct stent which was removed after 3 months. We found no statistically
significant correlation between pancreatic duct clearance and age, gender, pancreatic
duct diameter, stone size, stone number, number of ESWL shocks, and number of ESWL
sessions. In our study patients were followed-up over a period of one and half years
and were assessed for pain status. The study conducted by Zhang et al[19 ] showed 75% of patients had complete pain relief and 16.7% patients had partial pain
relief after ESWL for PD calculi. While the study by Tandan et al[24 ] revealed complete pain relief in 84.4% and partial pain relief in 12.3% patients
after ESWL. We found that in majority of patients 15 (71.4%), there was complete pain
relief and in 3 patients (14.2%) there was some improvement in pain and in other 3
patients (14.2%) pain persisted ([Fig. 5 ]).
Fig. 5 Pain relief after extra corporeal shock wave lithotripsy for pancreatic duct calculi.
Conclusion
ESWL is an effective and safe treatment which improves the outcome of biliary and
pancreatic duct stones. Clearance of difficult and large CBD calculi with duct clearance
rate of more than 92.5% and pancreatic duct calculi with duct clearance rate of 100%
can be achieved. Major complications included pancreatitis (2.5%) and hemobilia (2.5%)
in Group A. Pain in the abdomen in 9.5% and echymosis in 4.7% occurred in Group B.
71.4% patients of chronic pancreatitis had complete pain relief, while 14.2% patients
had some improvement in pain and 14.2% of patients had no relief of pain.
