Cardiovasc Intervent Radiol (t992) 15:247-250
CardioVascular andInterventional Radiology 9 Springer-Verlag New York Inc. t992
Dissolution of Multiple Biliary Duct Stones Using Methyl Tert-Butyl Ether (MTBE): Experience in Two Cases Ricardo Tobio-Calo, ~ Jose M. Llerena,: Isabel Pinto-Pabon. 2 and Wilfrido R. Castafieda-Zufiiga: ~Department of Radiology, Hospital Central de la Cruz Roja. Madrid {Spa,n): and :Department of Radiology. University of Minnesota Hospital, Minneapolis, Nhnnesota, USA
Abstract. Methyl tert-butyl-ether (MTBE) was successfully used for stone dissolution in 2 patients with multiple bile duct cholesterol stones. The presence of a biliary-enteric anastomosis precluded the endoscopic approach. Because of leakage of MTBE into the bowel, dissolution time ranged from 7.5 to 36 h. No significant complications other than mild nausea were encountered. No recurrence of stone formation has been found at a follow-up varying fl-om 9 to 12 months.
we report 2 patients with a biliary-enteric anastomosis in whom multiple cholesterol stones within the intra- and extrahepatic biliary tree were completely dissolved with MTBE.
Key words: Chotehthiasis--Biliary duct stones, cholangiography~Methyl tert-butyl ether, cholesterol stones
A 48-year-old mate with a history of cholecystectomy 10 year~ prior presented with signs and symptom,, of blhary tree obstruction and elevated levels of btlirubin fl8 mg~l. Ultrasound (US) and percutaneous cholangiography (PTC) demonstrated multiple small stones measuring bet~veen 3 and 8 mm m diameter within the ddated intra- and extrahepatic blliary ducts. The patient under,,,,ent surgery at which tm~e multiple stone.,, ,,~ere removed fiom the common bile duct. A choledocojejunostomy and external drainage ,aqth a T-tube were also pert\~rmed. A postsurgical cholangiogram showed patencv of the bltiary-enterlc anastomosis and multiple residuat stones located mainly m the mtrahepatic bfltary tree{Fig [A). It was decided to attempt dissolution of the residual stones with MTBE. taking into account the purely cholesterol composition of the stones found at surgery. The T-tube was exchanged for a pigtail catheter that was placed at the level of the confluence of the right and left hepatic ducts. To avmd intestinal toxicity by absorption of MTBE. the choledocojejunostomy was occluded with a balloon catheter. Unfortunately, the ether dissolved the .latex balloon. This catheter was replaced by a 12-ram angiopla~ty balloon that onb achieved partial occlusion of the biliary-enteric anastomosis. MTBE >,as rejected through the pigtail catheter into the bile ducts in 5-ml increments and was aspirated after 15 min. This procedure ~vas repeated until complete dissolution of the stones was observed. A total volume of 533 ml of MTBE was injected during 26 h of treatment to achmve complete stone dissolution {Fig. 1BI. Nausea and vomiting occurred at the begmmng of each period of treatment but did not require therapy. Mild drowsiness probably caused by' intestinal absorption of ether was noted during the treatment. There were no changes in the hepatic and pancreahc enzymes levels. Cholangmgraphy and sonography of the bihary tree following dissolution did not show residual stones, and the pigtail catheter was removed 2 da~s later The patient remains asymptomatic at 1-year fo]low-up.
In recent years, there has been an increasing interest in the nonsurgical management of stones within the gallbladder and biliary ducts for high-surgical risk patients, for those with multiple previous surgeries. or for patients that refused surgery [[-9]. Methyl tert-butyl ether (MTBE) is a new solvent that has been used successfully in the treatment of cholelithiasis and choledocholithiasis. MTBE dissolves cholesterol stones 50 times faster than monooctanoin (MO) [1] and has been associated with few adverse effects [2. 3, 5-8]: however, it is less effective against bile duct stones of mixed composition that contain bilirubinates or carbonates. Some authors have reported the decrease in size of mixed composition stones with MTBE, apparently due to the dissolution of the cholesterol component, leading to easier mechanical removal [7, 8]. In this article,
Address reprint reque.~ts to: Witfrido R. Castafieda-Zt~fllga. M.D., Umversity of Minnesota Hospital and Clinic, Box 292 UMHC, 420 Delaware Street S.E., Minneapolis. MN 55455. USA
Case Reports Case 1
248
R. Tobio-Calo et al.: MTBE for Bflmry Duct Stones
..::~.., 9
:,:,,!.
,
, '.
{.
B
Fig, 1. Case I. A T-tube cholangiogram shows multiple re~tdual stones within the dilated intra- and extrahepatic bihary ducts and a patent choledochojejunostomy. B Follow-up cholanglogram demonstrate~ complete disbolut~on of the bflmr? duct ~tones after treatment w~th MTBE,
Case 2 A 42-year-old male wtth a history of cholecystectomy in 1980, and choledocojejunostomy for postsurgical strtcture in 1982. presented with obstructlve jaundice and elevated levels of bilirubm (25 mg,C'c). US and PTC showed intra- and extrahepatic blhary duct dilatation, as ~ell as multiple stones filling the intrahepattc branches of the biliary tree, PTC also demonstrated severe stenosis of the choledocojejunostomy. Computed tomography shox~ed no evidence of calcification within the stones. Percutaneous external biliary drainage was performed placing an 8F pigtail catheter. A cholangiogram showed multiple stones within the intrahepatic bfliary radicles and a severe stenosis at the choledocojejunostomy, with minimal passage of contrast material into the duodenum (Fig. 2A). Therapy with MTBE was initiated after the bilirubin levels decreased to 6 mg9,~. The stenosis at the bihary-enteric anastomosis avoided the necessity of obstructing the choledocojejunostomy with a balloon catheter. MTBE was injected in increments of 2 ml through the pigtail catheter and aspirated 5 rain later. After 7J/-_ h of treatment, with the injection
of a total volume of 176 ml of MTB E, the stones were completely dissolved (Fig. 2BI. The patient onl,,,' complained of mild eplgastric discomfort at the begmmng of the MTBE treatment that resolved spontaneously. Ether odor on the patient's breath was detected during each per)od of therapy No changes m the hepatic or pancreatic enzymes were detected. Subsequentl,,, the anastomotic stenos~s was ddated and a Glanturco bihar,, metallic endoprosthesls was placed. The pigtail catheter wa~ removed 7 days after dilatation. The patmnt ,a as as> mptomat~c 9 months after treatment, sonography of the bfllary tree at this time was unremarkable.
Discussion
In 1985, Allen et al. [I] demonstrated in vitro that MTBE was very effective for dissolving cholesterol stones, acting 50 times faster than MO, Also, MTBE dissolved completely not only the 94% cholesterol stones but also the stones with a 40% cholesterol content [l]. In vivo studies performed in dogs verified the in vitro effectiveness of MTBE and also showed lack of toxicity of this agent on the gallbladder and common bile duct (CBD), however, the dissolution time was longer than that observed in the in vitro studies [1]. The first clinical application of
R. "l'~bto-Calo et at.. M T B E fl~r Bfliary Duct Stone,~
249
-A
i ,..
~
I:
,~
III_~ ~-,-"/"....
Fig. 2. Ca',e 2 A Chol:mgtogram through a percutuneou~, bthztr,~ drainage catheter ,,ho~'~,, multlpte ',tones ~,Vlthm the d~lated blhnr~ tree and a po,,tsurglcal stricture at the bfltar?-entcr~, ana'~lomost'~ {arrow) that ullow', s o m e flow of contra>t mid the j e l u n u m B Dissolution of the stone', is demom, trated m the chol,~nglogram p o s t - M T B E treatment. Ag,~m noted is the strtcture ,it the c h o t e d o c o j e j u n o s t o m y {arro'~v ).
M T B E was reported by Allen et al. m 2 patmnts with stones within the gallbladder and btliary tree. C o m p l e t e stone dissolution was found after 7 and 4 h o f treatment, r e s p e c t i v e l y [2]. In 1986, Van Sonnenberg et al. [3] r e p o r t e d a case of cystic duct stone dissolution after 20 h of M T B E treatment. Dissolution o f biliary tree stones may be complicated by the local effects of ether on the intestinal m u c o s a [4]. Occlusion of the distal C B D or biliary/ enteric a n a s t o m o s i s with a balloon catheter not only avoids the passage of ether into the intestinal tract but also provides a closed s y s t e m that facilitates and e x t e n d s the time of c o n t a c t of the stones with the solvent. In out" 2 patients, the p r e s e n c e of a surgical biliary-enteric a n a s t o m o s i s precluded endoscopic stone removal. In addition, the large stone load and widespread distribution would have made e n d o s c o p i c
manipulation difficult. The pure cholesterol c o m p o sition of the stones found at surgery m I patient strongly f a v o r e d the use of M T B E . In the other patient, a chemical stone analysis was not available. In our first patmnt, we o b t a i n e d only partial occlusion of the bitiary enteric a n a s t o m o s i s which could explain the nausea, vomiting, and the prolonged M T B E t r e a t m e n t time. This was not o b s e r v e d in ottr second patient in w h o m a tight stenosis of the a n a s t o m o s i s precluded substantial p a s s a g e of M T B E to the small bo~vel. Most o f the clinical e x p e r i e n c e with M T B E has been acquired in the t r e a t m e n t of gallbladder stones. M T B E ha,~ been found to be effective by Thistle et al. [5] who obtained stone dissolution in 72 of his 75 patients, after a mean t r e a t m e n t time of 12% h. On the other hi:nd, the efficacy of M T B E in dtssolving c o m m o n hepatic duct (CH D) or CB D stone~ ha,~ been questioned b? ~ome at,tthor,~ 16-8]. [n 1987, Teplick et al. 16] reported dissolution of C B D stones in only one out of 3patients ~ith a single C B D stone. Brandon et al. [71 reported dissolution of C H D stones in 2 ont of l0 patients: mechanical extractton with basket was used in the remaining 8 patient~. A similar experience was reported by Van S o n n e n b e r g et al. IS] who used MO and/or basket extraction for the treatment of the undissolved stone~. In our 2 ca.',es, we obtained ~t c o m p l e t e dissoh|tton of the biliary tree stones without any a d j u v ~ t n I t r e a t m e n t a n d no evidence of recurrence after 9 and 12 months, respectjvet~. At the present time, treatment w'~th M I'BE is a t~me-consuming p r o c e d u r e that requires continuous monitoring during injection and aspiration of the sotvent. D e v e l o p m e n t of a mechanical p u m p could solve this p r o b l e m in the near future. Also, a recent itt v i t r o study by Faulkner and K o z a r e k [9] has demonstrated that the time of t r e a t m e n t m a y d e c r e a s e significantly if stone fragmentation with a laser is performed pNor to the injection of M T B E . Clinical experience also needs to be obtained to confirm the itz v i t r o results that suggested that the injection of biD followed b~ M T B E provides better results than those o b s e r v e d with 3dTBE alone [10]. In conclusion, M T B E is an important t h e r a p e u t i c option for patients with a high surgical risk or history of repeated surgical p r o c e d u r e s who present with cholesterol stones within the biliary tree, Adjuvant measures like mechanical extraction or lithotripsy m a y be used in patients with incomplete stone dissolution.
References 1. Allen M J, Borody TJ. B u g h o s l T F . May G R . L a R u s s o N F . Thistle JL (1985) Cholelitholysis using methyl tertiary butyl ether, G a s t r o e n t e r o l o g y 88:122-t25
250 2. Allen MJ, Borody TJ, Bugliosi TF, May GR, LaRusso NF, Thistle JL ( 19851 Rap~d dissolution of gallstones by methyl tert-butyl ether. N Engl J Med 312:217-220 3. Van Sonnenberg E, Hofmann AF. Neopltolemus J, Wlttich GR, Princenthal RA, Willson SW (1986) Gallstone dissolution with methyl-tert-butyl ether via percutaneous cholecystostomy: Success and caveats. A JR t46:865-867 4. Di Padova C. Di Padova F, Montorsi W, Tritapepe R ~'19861 Methyl tert-butyl ether fails to dissolve retained radiolucent common bite duct stones. Gastroenterology 91 : 1296-1300 5. Thistle JL, May GR, Bender CE, Williams H J. Le Roy A J, Nelson PE, Peine CJ, Petersen BT, McCullough JE 11989) Dissolution of cholesterol gallbladder stones by methyl tertbutyl ether admin,stered by percutaneous transhepatic catheter. N Engt J Med 320:633-639 6. Teplick SK, Haskm PH, Goldstein RC, Corvasce JM, Frank EB, Sammon JK, Hofman AF ( 19871 Common bile duct stone
R. Tobio-Calo et al.: MTBE for Biliary Duct Stones
7.
8.
9. t0.
dissolution with methyl tertiary butyl ether: Experience with three patients. A JR 148:372-374 Brandon JC, Teplick SK, Haskin PH, Sammon JK, Muhr WF, Hofmann AF, Gambescia RA, Zitomer N (19881 Common bile duct calculi: Updated experience with dissolution with methyl tertiary butyl ether. Radiology 166:665667 Van Sonnenberg E, Casola G, Zakko SF, Varney RR, Cox J, Wittich GR, Hofmann AF (19881 Gallbladder and bsle duct stones: Percutaneous therapy with primary MTBE dissolution and mechanical methods. Radiology 169:505-509 Faulkner DJ, Kozarek RA (1989) Gallstones: Fragmentation with a tunable dye laser and dissolution with methyl tertbutyl ether in vitro. Radiology 170:185-189 Oldershaw JH, Epstein NF, Potter JE, Clouse ME (1989) Chemical dissolution of gallstones: In vitro studies. Radiology 172'987-990
CardioVascular andInterventional Radiology 9 Springer-Verlag New York Inc. t992
Dissolution of Multiple Biliary Duct Stones Using Methyl Tert-Butyl Ether (MTBE): Experience in Two Cases Ricardo Tobio-Calo, ~ Jose M. Llerena,: Isabel Pinto-Pabon. 2 and Wilfrido R. Castafieda-Zufiiga: ~Department of Radiology, Hospital Central de la Cruz Roja. Madrid {Spa,n): and :Department of Radiology. University of Minnesota Hospital, Minneapolis, Nhnnesota, USA
Abstract. Methyl tert-butyl-ether (MTBE) was successfully used for stone dissolution in 2 patients with multiple bile duct cholesterol stones. The presence of a biliary-enteric anastomosis precluded the endoscopic approach. Because of leakage of MTBE into the bowel, dissolution time ranged from 7.5 to 36 h. No significant complications other than mild nausea were encountered. No recurrence of stone formation has been found at a follow-up varying fl-om 9 to 12 months.
we report 2 patients with a biliary-enteric anastomosis in whom multiple cholesterol stones within the intra- and extrahepatic biliary tree were completely dissolved with MTBE.
Key words: Chotehthiasis--Biliary duct stones, cholangiography~Methyl tert-butyl ether, cholesterol stones
A 48-year-old mate with a history of cholecystectomy 10 year~ prior presented with signs and symptom,, of blhary tree obstruction and elevated levels of btlirubin fl8 mg~l. Ultrasound (US) and percutaneous cholangiography (PTC) demonstrated multiple small stones measuring bet~veen 3 and 8 mm m diameter within the ddated intra- and extrahepatic blliary ducts. The patient under,,,,ent surgery at which tm~e multiple stone.,, ,,~ere removed fiom the common bile duct. A choledocojejunostomy and external drainage ,aqth a T-tube were also pert\~rmed. A postsurgical cholangiogram showed patencv of the bltiary-enterlc anastomosis and multiple residuat stones located mainly m the mtrahepatic bfltary tree{Fig [A). It was decided to attempt dissolution of the residual stones with MTBE. taking into account the purely cholesterol composition of the stones found at surgery. The T-tube was exchanged for a pigtail catheter that was placed at the level of the confluence of the right and left hepatic ducts. To avmd intestinal toxicity by absorption of MTBE. the choledocojejunostomy was occluded with a balloon catheter. Unfortunately, the ether dissolved the .latex balloon. This catheter was replaced by a 12-ram angiopla~ty balloon that onb achieved partial occlusion of the biliary-enteric anastomosis. MTBE >,as rejected through the pigtail catheter into the bile ducts in 5-ml increments and was aspirated after 15 min. This procedure ~vas repeated until complete dissolution of the stones was observed. A total volume of 533 ml of MTBE was injected during 26 h of treatment to achmve complete stone dissolution {Fig. 1BI. Nausea and vomiting occurred at the begmmng of each period of treatment but did not require therapy. Mild drowsiness probably caused by' intestinal absorption of ether was noted during the treatment. There were no changes in the hepatic and pancreahc enzymes levels. Cholangmgraphy and sonography of the bihary tree following dissolution did not show residual stones, and the pigtail catheter was removed 2 da~s later The patient remains asymptomatic at 1-year fo]low-up.
In recent years, there has been an increasing interest in the nonsurgical management of stones within the gallbladder and biliary ducts for high-surgical risk patients, for those with multiple previous surgeries. or for patients that refused surgery [[-9]. Methyl tert-butyl ether (MTBE) is a new solvent that has been used successfully in the treatment of cholelithiasis and choledocholithiasis. MTBE dissolves cholesterol stones 50 times faster than monooctanoin (MO) [1] and has been associated with few adverse effects [2. 3, 5-8]: however, it is less effective against bile duct stones of mixed composition that contain bilirubinates or carbonates. Some authors have reported the decrease in size of mixed composition stones with MTBE, apparently due to the dissolution of the cholesterol component, leading to easier mechanical removal [7, 8]. In this article,
Address reprint reque.~ts to: Witfrido R. Castafieda-Zt~fllga. M.D., Umversity of Minnesota Hospital and Clinic, Box 292 UMHC, 420 Delaware Street S.E., Minneapolis. MN 55455. USA
Case Reports Case 1
248
R. Tobio-Calo et al.: MTBE for Bflmry Duct Stones
..::~.., 9
:,:,,!.
,
, '.
{.
B
Fig, 1. Case I. A T-tube cholangiogram shows multiple re~tdual stones within the dilated intra- and extrahepatic bihary ducts and a patent choledochojejunostomy. B Follow-up cholanglogram demonstrate~ complete disbolut~on of the bflmr? duct ~tones after treatment w~th MTBE,
Case 2 A 42-year-old male wtth a history of cholecystectomy in 1980, and choledocojejunostomy for postsurgical strtcture in 1982. presented with obstructlve jaundice and elevated levels of bilirubm (25 mg,C'c). US and PTC showed intra- and extrahepatic blhary duct dilatation, as ~ell as multiple stones filling the intrahepattc branches of the biliary tree, PTC also demonstrated severe stenosis of the choledocojejunostomy. Computed tomography shox~ed no evidence of calcification within the stones. Percutaneous external biliary drainage was performed placing an 8F pigtail catheter. A cholangiogram showed multiple stones within the intrahepatic bfliary radicles and a severe stenosis at the choledocojejunostomy, with minimal passage of contrast material into the duodenum (Fig. 2A). Therapy with MTBE was initiated after the bilirubin levels decreased to 6 mg9,~. The stenosis at the bihary-enteric anastomosis avoided the necessity of obstructing the choledocojejunostomy with a balloon catheter. MTBE was injected in increments of 2 ml through the pigtail catheter and aspirated 5 rain later. After 7J/-_ h of treatment, with the injection
of a total volume of 176 ml of MTB E, the stones were completely dissolved (Fig. 2BI. The patient onl,,,' complained of mild eplgastric discomfort at the begmmng of the MTBE treatment that resolved spontaneously. Ether odor on the patient's breath was detected during each per)od of therapy No changes m the hepatic or pancreatic enzymes were detected. Subsequentl,,, the anastomotic stenos~s was ddated and a Glanturco bihar,, metallic endoprosthesls was placed. The pigtail catheter wa~ removed 7 days after dilatation. The patmnt ,a as as> mptomat~c 9 months after treatment, sonography of the bfllary tree at this time was unremarkable.
Discussion
In 1985, Allen et al. [I] demonstrated in vitro that MTBE was very effective for dissolving cholesterol stones, acting 50 times faster than MO, Also, MTBE dissolved completely not only the 94% cholesterol stones but also the stones with a 40% cholesterol content [l]. In vivo studies performed in dogs verified the in vitro effectiveness of MTBE and also showed lack of toxicity of this agent on the gallbladder and common bile duct (CBD), however, the dissolution time was longer than that observed in the in vitro studies [1]. The first clinical application of
R. "l'~bto-Calo et at.. M T B E fl~r Bfliary Duct Stone,~
249
-A
i ,..
~
I:
,~
III_~ ~-,-"/"....
Fig. 2. Ca',e 2 A Chol:mgtogram through a percutuneou~, bthztr,~ drainage catheter ,,ho~'~,, multlpte ',tones ~,Vlthm the d~lated blhnr~ tree and a po,,tsurglcal stricture at the bfltar?-entcr~, ana'~lomost'~ {arrow) that ullow', s o m e flow of contra>t mid the j e l u n u m B Dissolution of the stone', is demom, trated m the chol,~nglogram p o s t - M T B E treatment. Ag,~m noted is the strtcture ,it the c h o t e d o c o j e j u n o s t o m y {arro'~v ).
M T B E was reported by Allen et al. m 2 patmnts with stones within the gallbladder and btliary tree. C o m p l e t e stone dissolution was found after 7 and 4 h o f treatment, r e s p e c t i v e l y [2]. In 1986, Van Sonnenberg et al. [3] r e p o r t e d a case of cystic duct stone dissolution after 20 h of M T B E treatment. Dissolution o f biliary tree stones may be complicated by the local effects of ether on the intestinal m u c o s a [4]. Occlusion of the distal C B D or biliary/ enteric a n a s t o m o s i s with a balloon catheter not only avoids the passage of ether into the intestinal tract but also provides a closed s y s t e m that facilitates and e x t e n d s the time of c o n t a c t of the stones with the solvent. In out" 2 patients, the p r e s e n c e of a surgical biliary-enteric a n a s t o m o s i s precluded endoscopic stone removal. In addition, the large stone load and widespread distribution would have made e n d o s c o p i c
manipulation difficult. The pure cholesterol c o m p o sition of the stones found at surgery m I patient strongly f a v o r e d the use of M T B E . In the other patient, a chemical stone analysis was not available. In our first patmnt, we o b t a i n e d only partial occlusion of the bitiary enteric a n a s t o m o s i s which could explain the nausea, vomiting, and the prolonged M T B E t r e a t m e n t time. This was not o b s e r v e d in ottr second patient in w h o m a tight stenosis of the a n a s t o m o s i s precluded substantial p a s s a g e of M T B E to the small bo~vel. Most o f the clinical e x p e r i e n c e with M T B E has been acquired in the t r e a t m e n t of gallbladder stones. M T B E ha,~ been found to be effective by Thistle et al. [5] who obtained stone dissolution in 72 of his 75 patients, after a mean t r e a t m e n t time of 12% h. On the other hi:nd, the efficacy of M T B E in dtssolving c o m m o n hepatic duct (CH D) or CB D stone~ ha,~ been questioned b? ~ome at,tthor,~ 16-8]. [n 1987, Teplick et al. 16] reported dissolution of C B D stones in only one out of 3patients ~ith a single C B D stone. Brandon et al. [71 reported dissolution of C H D stones in 2 ont of l0 patients: mechanical extractton with basket was used in the remaining 8 patient~. A similar experience was reported by Van S o n n e n b e r g et al. IS] who used MO and/or basket extraction for the treatment of the undissolved stone~. In our 2 ca.',es, we obtained ~t c o m p l e t e dissoh|tton of the biliary tree stones without any a d j u v ~ t n I t r e a t m e n t a n d no evidence of recurrence after 9 and 12 months, respectjvet~. At the present time, treatment w'~th M I'BE is a t~me-consuming p r o c e d u r e that requires continuous monitoring during injection and aspiration of the sotvent. D e v e l o p m e n t of a mechanical p u m p could solve this p r o b l e m in the near future. Also, a recent itt v i t r o study by Faulkner and K o z a r e k [9] has demonstrated that the time of t r e a t m e n t m a y d e c r e a s e significantly if stone fragmentation with a laser is performed pNor to the injection of M T B E . Clinical experience also needs to be obtained to confirm the itz v i t r o results that suggested that the injection of biD followed b~ M T B E provides better results than those o b s e r v e d with 3dTBE alone [10]. In conclusion, M T B E is an important t h e r a p e u t i c option for patients with a high surgical risk or history of repeated surgical p r o c e d u r e s who present with cholesterol stones within the biliary tree, Adjuvant measures like mechanical extraction or lithotripsy m a y be used in patients with incomplete stone dissolution.
References 1. Allen M J, Borody TJ. B u g h o s l T F . May G R . L a R u s s o N F . Thistle JL (1985) Cholelitholysis using methyl tertiary butyl ether, G a s t r o e n t e r o l o g y 88:122-t25
250 2. Allen MJ, Borody TJ, Bugliosi TF, May GR, LaRusso NF, Thistle JL ( 19851 Rap~d dissolution of gallstones by methyl tert-butyl ether. N Engl J Med 312:217-220 3. Van Sonnenberg E, Hofmann AF. Neopltolemus J, Wlttich GR, Princenthal RA, Willson SW (1986) Gallstone dissolution with methyl-tert-butyl ether via percutaneous cholecystostomy: Success and caveats. A JR t46:865-867 4. Di Padova C. Di Padova F, Montorsi W, Tritapepe R ~'19861 Methyl tert-butyl ether fails to dissolve retained radiolucent common bite duct stones. Gastroenterology 91 : 1296-1300 5. Thistle JL, May GR, Bender CE, Williams H J. Le Roy A J, Nelson PE, Peine CJ, Petersen BT, McCullough JE 11989) Dissolution of cholesterol gallbladder stones by methyl tertbutyl ether admin,stered by percutaneous transhepatic catheter. N Engt J Med 320:633-639 6. Teplick SK, Haskm PH, Goldstein RC, Corvasce JM, Frank EB, Sammon JK, Hofman AF ( 19871 Common bile duct stone
R. Tobio-Calo et al.: MTBE for Biliary Duct Stones
7.
8.
9. t0.
dissolution with methyl tertiary butyl ether: Experience with three patients. A JR 148:372-374 Brandon JC, Teplick SK, Haskin PH, Sammon JK, Muhr WF, Hofmann AF, Gambescia RA, Zitomer N (19881 Common bile duct calculi: Updated experience with dissolution with methyl tertiary butyl ether. Radiology 166:665667 Van Sonnenberg E, Casola G, Zakko SF, Varney RR, Cox J, Wittich GR, Hofmann AF (19881 Gallbladder and bsle duct stones: Percutaneous therapy with primary MTBE dissolution and mechanical methods. Radiology 169:505-509 Faulkner DJ, Kozarek RA (1989) Gallstones: Fragmentation with a tunable dye laser and dissolution with methyl tertbutyl ether in vitro. Radiology 170:185-189 Oldershaw JH, Epstein NF, Potter JE, Clouse ME (1989) Chemical dissolution of gallstones: In vitro studies. Radiology 172'987-990
