CASE REPORT 519

Clinical Radiology (1996) 51, 519-520

Case Report: A Migrating Complication

D. T A R V E R a n d G. R. P L A N T

Department of Radiology, North Hampshire Hospital, Basingstoke, Hants, UK

Biliary Wallstent: An Unusual

O n l y one case o f m i g r a t i o n o f a b i l i a ry W a l l s t e n t has been r e p o r t e d . W e r e p o r t a case o f p r o x i m a l m i g r a t i o n o f a b i l i a ry W a l l s t e n t p l a c e d for m a l i g n a n t o b s t r u c t i o n o f t he d i s ta l c o m m o n bi le duct . R e a s o n s fo r s t en t m i g r a t i o n in this pa t i en t , a n d poss ib le ways to a v o i d this u n u s u a l c o m p l i c a t i o n are d iscussed.

completely eradicate the constriction but rapid flow was seen through the Wallstent complex into the duodenum. A temporary external drain was left in situ and the following day a cholangiogram performed. This demonstrated excellent flow through the stents.

Serial abdominal radiographs demonstrated progressive dilatation of the stent system and no evidence of further migration up to the time of the patient's death from disseminated malignancy three months later

CASE REPORT

A 66-year-old retired Civil Servant was referred for investigation of jaundice. Ultrasound (US) and computed tomography (CT) demonstrated a dilated biliary tree and a 5 cm mass in the head of the pancreas, the appearances of which were consistent with pancreatic carcinoma.

Percutaneous cholangiography and biliary drainage demonstrated obstruction of the common bile duct (CBD) in the region of the expanded head of pancreas. An unusual configuration of the common bile duct was noted with a horizontally placed proximal section ending in an acute angle immediately above the stenosis (Fig. 1). A 10 F double mushroom plastic stent (Mtiller) was positioned through the obstruction to allow internal drainage. Over the next few days there was rapid clearance of jaundice allowing the patient to be discharged.

Nine months later the patient returned with recurrent jaundice. US examination demonstrated biliary obstruction which was presumed to be due to either tumour overgrowth around the stent or blockage by deposition of biliary sludge [1]. However, a percutaneous cholangio- gram demonstrated the stent lying within the horizontal portion of the CBD proximal to the previously demonstrated obstruction. Removing the existing plastic stent would have necessitated dilatation of a tract to approximately 14F to withdraw it through the liver and percuta- neously, or a complex manipulation through the stricture itself, round a tight bend into the lower CBD and then down through the ampulla and into the duodenum. We felt this was clinically inap- propriate and elected to leave the stent where it was. Internal/external biliary drainage was instituted and the following day a 10 mm biliary Wallstent (No:2C0013-001) (Schneider, Btilach, Switzerland) was inserted through the stenosis. The distal end of the stent was positioned in the lower CBD, approximately 2 cm distal to the obstruction (Fig. 2). The stenotic area was dilated to 7 mm before placing the stent although, despite prolonged high pressure inflations, the stenosis could not be completely eradicated. After uneventful deployment the stenosis was again dilated and again the residual constriction remained. There was good flow through the stent and over the next few days it slowly increased in diameter. The jaundice cleared over the following few days and the patient was discharged.

One month later the patient re-presented with jaundice and a US examination demonstrated biliary obstruction. A plain abdominal radiograph demonstrated that the Wallstent had migrated proximally and was lying alongside the older plastic stent (Fig. 3). Percutaneous cholangiography confirmed this and demonstrated that the Wallstent was now lying within the horizontal segment of the CBD with the distal end tapering into the mouth of the obstructed segment,

A catheter was passed through the Wallstent, through the obstruc- tion and into the duodenum and a second Wallstent positioned with the proximal end approximately 2 cm above the obstruction and lying co-axially within the first Wallstent. The distal end was placed in the duodenum (Fig. 4). The residual stenosis within the stent complex was dilated with a 9mm balloon catheter. It was still not possible to

Correspondence to: Dr G. R. Plant, Department of Radiology, North Hampshire Hospital, Aldermaston Road, Basingstoke; Hants RG24 9NA, UK.

© 1996 The Royal College of Radiologists, Clinical Radiology, 51, 519-520.

D I S C U S S I O N

O n l y one p r e v i o u s r e p o r t o f m i g r a t i o n o f a b i l ia ry W a l l s t e n t has b e e n p u b l i s h e d [2] and Mt i l l e r et al. h a v e r e p o r t e d t w o poss ib le m i g r a t i o n s [3]. T w o la rge series o f 41 and 45 p a t i e n t s [4,5] r e p o r t e d no ins tances o f m i g r a t i o n . A b r a m s o n et al. [2] r e p o r t e d a case in w h i c h d is ta l m i g r a t i o n o c c u r r e d w h e n W a l l s t e n t s were s imul- t a n e o u s l y d e p l o y e d in the r igh t a n d left h e p a t i c duc t s in a ' k i s s ing s ten t ' m a n o e u v r e fo r a ga l l b l adde r c a r c i n o m a caus ing s tenosis o f t he d u c t b i fu r ca t i on . T o o u r k n o w l - edge n o cases o f p r o x i m a l m i g r a t i o n o f a b i l iary W a l l s t e n t h a v e b e e n r epo r t ed . By con t r a s t , b e t w e e n 4 % a n d 10% o f p las t ic b i l i a ry s tents m i g r a t e [6].

I n o u r case the re was p r o x i m a l m i g r a t i o n o f b o t h a p las t ic M/ i l l e r s t en t a n d a Wa l l s t en t , I t is l ikely tha t the u n u s u a l a n a t o m y o f this p a t i e n t (i.e. a h o r i z o n t a l l y p l a c e d C B D wi th an acu t e ang le in the d u c t j u s t p r o x i m a l to t he o b s t r u c t i o n ) p r e d i s p o s e d to ins tab i l i ty o f the

Fig. 1 - Percutaneous cholangiogram demonstrating an obstructed distal common bile duct. The proximal part of the duct is unusually horizontal with an acute angle just above the obstruction.

520 CLINICAL RADIOLOGY

Fig. 2 The original position of the original Wallstent showing two centimetres of stent below the stenosis but with the distal end within the CBD.

Fig. 4 - Second Wallstent through obstruction, with proximal end within original Wallstent and distal end in duodenum.

the CBD. It has since become common practice to pass the lower end of metallic stents through the ampulla of Vater into the duodenum, a technique which might have provided superior fixation in this case and prevented migration. With only 2cm of Wallstent below the obstruction the stent may have been relatively mechani- cally unstable. It is now our practice to place a longer stent from close to the origin of the CBD through into the duodenum in cases where the geometry of the lesion predisposes to migration.

In conclusion, we believe that the possibility of migration of a biliary Wallstent can be minimized by positioning the stent with the stenosis towards the middle of the stent and normally with the distal end of the stent in the duodenum. We dilate a balloon catheter inside the stent and try to avoid placing two stents in parallel when this is feasible.

Fig. 3 - Parallel Mtiller and Wallstent stents which have both migrated proximal to the obstruction. The distal tip of the Wallstent tapers into the obstructed segment.

stents, despite the extreme flexibility of the Wallstent and balloon dilatation of the Wallstent after insertion to impact it into the walls of the bile duct. Although a larger dilation may have made the stenosis less likely to extrude the stent it was not possible to eradicate the narrowing with a 7 mm balloon and we feel it unlikely that a larger balloon would have been more effective.

As in the case of Abramson et al. [2] the parallel placement of two stents (in our case, one metallic and one plastic) might have contributed to instability. In our case, the initial Wallstent was positioned entirely within

REFERENCES

1 Huilbregste K, Carr-Locke DL, Cremer M e t al. Biliary stent occlusion a problem solved with self-expanding metal stents? Endoscopy 1992;24:39l 394.

2 Abramson AF, Javit DJ, Mitty JA et al. Wallstent migration following deployment in right and left ducts. Journal of Vascular and Interventional Radiology 1992;3:463-465.

3 Mueller PR, Boston MA, Tegtmeyer CJ et al. Metallic biliary stents: early experience (abstr)., Radiology 1990:177:138.

4 Adam A, Chetty N, Robbie M e t al. Self-expandable stainless steel endoprnsthesis for treatment of malignant bile duct. American Journal of Roentgenology 1991;156:321-325.

5 Gilliams A, Dick R, Dooley JS et al. Self-expandable stainless steel braided endoprosthesis for biliary strictures. Radiology 1990;174:137-140.

6 Johanson JF, Schmalz MK, Geenen JE. Incidence and risk factors for biliary and pancreatic stent migration. Gastrointestinal Endoscopy 1992;38:341-346.

© 1996 The Royal College of Radiologists, Clinical Radiology, 51, 519 520.