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Removal of a Covered Esophageal Metallic Stent 8 Years after Placement
Removal of a Covered Esophageal Metallic Stent 8 Years after Placement Eugene K. Choi, BA, Ho-Young Song, MD, Ji-Hoon Shin, MD, and Jae-Wook Kim, MD
A covered expandable esophageal metallic stent was placed to treat a corrosive esophageal stricture that was refractory to repeated balloon dilations. The stent was removed 8 years after placement due to severe dysphagia. The stented esophageal area has since maintained long-term patency for 2 years. These results suggest the feasibility of removal of a metallic stent after long-term stent placement. J Vasc Interv Radiol 2007; 18:317–320
EXPANDABLE stents are commonly used as a minimally invasive treatment for malignant esophageal strictures and fistulas (1–3). However, the convention has been that stent placement is rarely indicated for benign esophageal strictures not only because of the effectiveness of balloon dilation but also because of reports of late adverse events of stent placement, especially stent-induced tissue hyperproliferation (4). Cases of successful treatment of esophageal strictures by means of temporary placement of retrievable stents for durations of 6 to 8 weeks have been reported (5,6). However, the fear of inducing serious esophageal injury when placing a stent on a permanent basis and belief in the impossibility of stent removal in cases of complications have discouraged placement of a stent for more than a few months duration. Herein
From the Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, 388-1 Pungnap2dong, Songpa-gu, Seoul 138-736, Republic of Korea (E.K.C., H-Y.S., J-H.S., J-W.K.); and Weill Medical College of Cornell University, New York, NY (E.K.C.). Received June 1, 2006; final revision received October 29, 2006; accepted November 6, 2006. Address correspondence to H-Y.S.; E-mail:hysong@ amc.seoul.kr None of the authors have identified a conflict of interest. © SIR, 2007 DOI: 10.1016/j.jvir.2006.11.004
we report the successful removal of a stent initially placed on a permanent basis for a benign corrosive stricture, resulting in its long-term resolution.
CASE REPORT This retrospective report was approved by our institutional review board, and patient informed consent for this review was waived. A 56-yearold male with a 10-year history of esophageal corrosive stricture secondary to acid ingestion was referred to our institution for surgical removal of an esophageal stent placed 8 years earlier at an outside institution. The patient previously had undergone gastrectomy with esophagojejunostomy for a severe gastric stricture induced by ingestion of corrosive agent. Thereafter, the patient also had undergone multiple sessions of fluoroscopic balloon dilations at the outside institution for esophageal corrosive strictures at two sites: one at the cervical esophagus and one at the midthoracic esophagus. Fluoroscopic balloon dilations using a 15-mm balloon catheter was repeated every month for the stricture located at the midthoracic esophagus and every 3 to 4 months for the stricture at the cervical esophagus. Given the frequent recurrence of the midthoracic stricture, stent placement was performed with an 18-mm-diameter, 6-cm-long, silicone-covered modified Gianturco stent tube designed by Song
et al (7). The stent consisted of proximal and distal shoulders (28 mm in diameter), which were connected at right angles to the main barrel portion. The wall thickness and luminal diameter of the introducing tube were 0.8 mm and 12.0 mm, respectively. After stent placement, the patient underwent esophageal balloon dilations every 3 to 4 months for the cervical esophageal stricture over an 8-year period, whereas the stricture located at the midthoracic esophagus did not need further dilation after stent placement. The patient presented to our institution complaining of severe dysphagia to both solids and liquids. The patient was referred to interventional radiology for a trial of balloon dilation and fluoroscopic stent removal after the patient refused the only surgical option of esophagocolonojejunostomy. Esophagography showed a severe stricture at the cervical esophagus and a moderate stricture at the distal end of the stent (Figure). Given the clinical symptoms of dysphagia and the radiographic evidence of two strictures, it was decided to address both the cervical stricture and the stent-induced midthoracic stricture via balloon dilation and stent removal. Fluoroscopic balloon dilation of the stricture at the cervical esophagus was performed using a 20-mm balloon catheter. During balloon dilation, an hourglass-shaped
317
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Figure. (a) Esophagogram prior to removal of stent placed for 8 years demonstrates strictures in the cervical (arrow) and midthoracic esophagus. Luminal narrowing is noted at the area just below the distal end of the stent (arrowhead). (b) Esophagogram at the time of stent removal demonstrates a collapsed stent being removed by a hook. Two sheaths of 9-mm (arrow) and 7-mm (arrowhead) diameter were used in stent removal. (c) Esophagogram demonstrates piece-by-piece removal of the fractured stent pieces (arrow) under both fluoroscopic and endoscopic guidance. (d) Esophagogram just after stent removal demonstrates good follow of contrast through the former site of stricture (arrowheads). (e) Esophagogram obtained 1 year after stent removal shows maintained improvement of the midthoracic stricture (arrowheads). The stricture in the cervical esophagus (arrows) shows good patency after repeated balloon dilations.
deformity of the balloon created by the stricture disappeared completely. An 0.035-inch guide wire (Radifocus M; Terumo, Tokyo, Japan) was introduced through the mouth and then across the stent into the distal portion of the esophagus. Modifying the standard stent removal protocol reported for covered retrievable stents (6,8), we used two coaxially placed sheaths for
stent removal. Initially, a 9-mm sheath was inserted past a narrowing in the proximal portion of the stent with the aid of a guiding balloon catheter. The inflation of the balloon catheter allowed passage of the 9-mm sheath across the narrowed proximal portion of the stent. The guide wire and balloon catheter were subsequently removed from the sheath and replaced
with a 7-mm sheath. Removal of the stent was performed with a 5-mm stent removal set including a hook by a previously described eversion technique (9) where the hook wire grasped the distal mesh of the stent and pulled it out in a way that caused the stent to be invaginated into itself and removed in an everted state. The stent, however, fractured during its removal.
Volume 18
Number 2
Only half of the fractured stent was removed successfully, whereas the remaining half could not be removed because of the difficulty in grasping the stent with the hook. The remaining pieces were subsequently removed piece by piece under both fluoroscopic and endoscopic guidance with a biliary biopsy forceps. The patient complained of mild pain during stent removal. Some parts of the removed stent were blood-stained, but there was no bleeding after stent removal. Although the patient underwent repeated dilations 6 to 8 months for stricture recurrence in the cervical esophagus with a 20-mm balloon catheter, the patient achieved long-term resolution of the midthoracic stricture treated with stent placement. A follow-up esophagography at 2 years after stent removal revealed maintained improvement of the midthoracic stricture.
DISCUSSION The permanent placement of esophageal stents is widely considered to be a contraindication in patients with benign strictures who have a reasonable expectation of longevity due to the high rate of late complications (4,10 – 12). The most severe complication in benign esophageal disease limiting long duration of stent placement is tissue hyperproliferation that is induced by the expansile forces exerted by the stent. Although there are conflicting reports on the timing of this complication (6,13,14), it is believed to be progressive once initiated, rendering stent removal virtually impossible because of the fears of the concomitant risks of esophageal wall perforation (14). Therefore, long-term stent placement in benign disease is generally contraindicated on the premise that excessive tissue hyperproliferation and resultant luminal obstruction would require radical surgery for stent removal. The current case is noteworthy for a number of reasons. First, it reports an unusually long duration of stent placement in a patient with an esophageal stricture. Given the relatively short life span of patients with malignant esophageal strictures and contraindication of permanent stent placement in patients with benign strictures, the results of stent placement of such
Choi et al
long-term duration have yet to be reported. Second, the current case demonstrates feasibility of stent removal after long-term placement. The concern about the necessity of surgical intervention in cases of excessive tissue hyperproliferation resulting from prolonged placement may in fact be unwarranted. The case demonstrates that stent placement of multiple-year duration may potentially be safely removed without incurring serious esophageal injury. Moreover, it also counters the belief that stents designed for permanent use cannot be removed short of surgical resection. This reports adds to the previously published cases of successful removal of other stents designed for permanent use, including the Ultraflex (Microvasive Endoscopy; Boston Scientific, Natick, Mass.) or Zesophageal stents (Wilson-Cook Medical, Winston-Salem, NC) where the stents were removed endoscopically by either grasping the proximal edge of the stent with a polyp snare or the distal edge with a rat-toothed forceps and invaginating the stent into itself (12,13,15). These methods, however, are disadvantaged by the high potential for esophageal wall injury. We therefore used two coaxially placed 9and 7-mm sheaths in stent removal where the outer 9-mm sheath served to protect the esophageal wall from injury during stent removal performed with the 7-mm sheath. More experiences will be needed to confirm the efficacy and safety of this technique. Recently, the availability of covered removable stents with a retrievable design has allowed effective and safe removal using a specifically designed retrievable hook (9). Song et al (6,8) used a stent with a drawstring attached to its upper inner margin, allowing a hook catheter to grasp and pull out the stent via the drawstring. Initial experiences with these retrievable stents inserted as a temporary measure have shown good early results (5,6). Given that the stent used in the current case lacked a retrievable feature, we used both an eversion technique with a retrievable hook and a forceps under endoscopic guidance for complete removal of the stent. A retrievable hook is very effective in securely attaching onto the mesh material of the stent, and thus using endoscopic techniques alone would have
•
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most likely been more technically difficult. The safety and efficacy of removing stents with a retrievable hook has been described in other locations, including the gastroduodenum, rectum (9), and urethra (16). Finally, the successful results of the case point to the importance of longterm stent duration in bringing about enduring satisfactory changes in treatment-resistant corrosive strictures. Although stent placement of 8-year duration represents an extreme example, the important lesson is that a duration significantly longer than the 6- to 8-week duration advocated by previous reports (5,6) may be necessary for induction of adequate stricture remodeling in resistant cases. Early experiences with temporary stent placement have shown that premature removal of stents is associated with high relapse rates of the primary stricture, resulting in repeated procedures with additional stent placements and/or balloon dilations (6). Although an optimal time for removing a stent placed in a benign esophageal stricture is not established (5,6,14), tailoring the duration of stent placement for each patient may be the most appropriate strategy. Strictures of corrosive etiology, for instance, are notorious for being highly treatment-resistant and require relatively long periods of stent placement compared with strictures of other benign etiology. It is generally our policy to maintain a minimum duration of stent placement of at least 4 months in such resistant cases. Aside from the balloon dilation performed at the time of stent removal, the midthoracic stricture managed with stent placement never required additional treatment. In comparison, a separate stricture at the cervical esophagus required repeated balloon dilation, which continued to the time of this writing. The lack of the need for additional treatment during stent placement (ie, balloon dilation) was due to the fact that tissue hyperproliferation did not manifest as an early complication resulting in exacerbation of clinical dysphagia symptoms. The study thus suggests two important points about stent-induced tissue hyperproliferation. First, the complication may be considerably delayed in certain cases allowing for extended time for stent placement. The reason for the wide range in the rate of tissue
320
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Esophageal Stent Removal 8 Years after Placement
hyperproliferation is unclear, but we suspect that the long-term fibrotic reaction and concomitant dense scarring common in long-standing corrosive strictures may contribute to the slower rate of tissue hyperproliferation compared with strictures of other etiologies. Second, contrary to previous thought, evolutionary changes in the esophagus secondary to tissue hyperproliferation is not necessarily progressive and may stabilize after a specific time. Considering the long length of stent placement, the stricture observed at the stent ends was relatively mild and most likely resulted from tissue hyperproliferation of limited duration. Therefore, early radiographic signs of tissue hyperproliferation do not necessarily warrant immediate stent removal so long as the patient is capable of maintaining a soft-food diet and can be easily followed. In conclusion, our case indicates both the feasibility of long-term stent placement and its safe removal necessary for producing satisfactory resolution of treatment-resistant benign strictures. Although more experiences are needed, we advocate a high threshold for stent removal in cases of refractory benign esophageal strictures in order to achieve the maximal duration of stent placement needed for long-term resolution. References 1. Cwikiel W, Tranberg KG, Cwikiel M, Lillo-Gil R. Malignant dysphagia: pal-
2.
3.
4.
5.
6.
7.
8.
9.
liation with esophageal stents—longterm results in 100 patients. Radiology 1998; 207:513–518. Do YS, Song HY, Lee BH, et al. Esophagorespiratory fistula associated with esophageal cancer: treatment with a Gianturco stent tube. Radiology 1993; 187: 673– 677. Song HY, Do YS, Han YM, et al. Covered, expandable esophageal metallic stent tubes: experiences in 119 patients. Radiology 1994; 193:689 – 695. Song HY, Park SI, Do YS, et al. Expandable metallic stent placement in patients with benign esophageal strictures: results of long-term follow-up. Radiology 1997; 203:131–136. Repici A, Conio M, De Angelis C, et al. Temporary placement of an expandable polyester silicone-covered stent for treatment of refractory benign esophageal strictures. Gastrointest Endosc 2004; 60:513–519. Song HY, Jung HY, Park SI, et al. Covered retrievable expandable nitinol stents in patients with benign esophageal strictures: initial experience. Radiology 2000; 217:551–557. Song HY, Choi KC, Kwon HC, Yang DH, Cho BH, Lee ST. Esophageal strictures: treatment with a new design of modified Gianturco stent. Work in progress. Radiology 1992; 184:729 –734. Song HY, Park SI, Jung HY, et al. Benign and malignant esophageal strictures: treatment with a polyurethanecovered retrievable expandable metallic stent. Radiology 1997; 203:747–752. Yoon CJ, Shin JH, Song HY, Lim JO, Yoon HK, Sung KB. Removal of retrievable esophageal and gastrointesti-
10.
11.
12.
13.
14.
15.
16.
JVIR
nal stents: experience in 113 patients. AJR Am J Roentgenol 2004; 183:1437– 1444. Cwikiel W, Willen R, Stridbeck H, Lillo-Gil R, von Holstein CS. Self-expanding stent in the treatment of benign esophageal strictures: experimental study in pigs and presentation of clinical cases. Radiology 1993; 187:667– 671. Tan BS, Kennedy C, Morgan R, Owen W, Adam A. Using uncovered metallic endoprostheses to treat recurrent benign esophageal strictures. AJR Am J Roentgenol 1997; 169:1281–1284. Wadhwa RP, Kozarek RA, France RE, et al. Use of self-expandable metallic stents in benign GI diseases. Gastrointest Endosc 2003; 58:207–212. Fiorini A, Fleischer D, Valero J, Israeli E, Wengrower D, Goldin E. Self-expandable metal coil stents in the treatment of benign esophageal strictures refractory to conventional therapy: a case series. Gastrointest Endosc 2000; 52:259 –262. Fukuda T, Hirota S, Matsumoto S, et al. Periodic endoscopic observation of postoperative esophageal stricture due to excessive tissue hyperproliferation after stent placement. Gastrointest Endosc 2001; 53:111–114. Low DE, Kozarek RA. Removal of esophageal expandable metal stents: description of technique and review of potential applications. Surg Endosc 2003; 17:990 –996. Shin JH, Song HY, Park H, et al. Removal of retrievable self-expandable urethral stents: experience in 58 stents. Eur Radiol 2006; 16:2037–2043.
A covered expandable esophageal metallic stent was placed to treat a corrosive esophageal stricture that was refractory to repeated balloon dilations. The stent was removed 8 years after placement due to severe dysphagia. The stented esophageal area has since maintained long-term patency for 2 years. These results suggest the feasibility of removal of a metallic stent after long-term stent placement. J Vasc Interv Radiol 2007; 18:317–320
EXPANDABLE stents are commonly used as a minimally invasive treatment for malignant esophageal strictures and fistulas (1–3). However, the convention has been that stent placement is rarely indicated for benign esophageal strictures not only because of the effectiveness of balloon dilation but also because of reports of late adverse events of stent placement, especially stent-induced tissue hyperproliferation (4). Cases of successful treatment of esophageal strictures by means of temporary placement of retrievable stents for durations of 6 to 8 weeks have been reported (5,6). However, the fear of inducing serious esophageal injury when placing a stent on a permanent basis and belief in the impossibility of stent removal in cases of complications have discouraged placement of a stent for more than a few months duration. Herein
From the Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, 388-1 Pungnap2dong, Songpa-gu, Seoul 138-736, Republic of Korea (E.K.C., H-Y.S., J-H.S., J-W.K.); and Weill Medical College of Cornell University, New York, NY (E.K.C.). Received June 1, 2006; final revision received October 29, 2006; accepted November 6, 2006. Address correspondence to H-Y.S.; E-mail:hysong@ amc.seoul.kr None of the authors have identified a conflict of interest. © SIR, 2007 DOI: 10.1016/j.jvir.2006.11.004
we report the successful removal of a stent initially placed on a permanent basis for a benign corrosive stricture, resulting in its long-term resolution.
CASE REPORT This retrospective report was approved by our institutional review board, and patient informed consent for this review was waived. A 56-yearold male with a 10-year history of esophageal corrosive stricture secondary to acid ingestion was referred to our institution for surgical removal of an esophageal stent placed 8 years earlier at an outside institution. The patient previously had undergone gastrectomy with esophagojejunostomy for a severe gastric stricture induced by ingestion of corrosive agent. Thereafter, the patient also had undergone multiple sessions of fluoroscopic balloon dilations at the outside institution for esophageal corrosive strictures at two sites: one at the cervical esophagus and one at the midthoracic esophagus. Fluoroscopic balloon dilations using a 15-mm balloon catheter was repeated every month for the stricture located at the midthoracic esophagus and every 3 to 4 months for the stricture at the cervical esophagus. Given the frequent recurrence of the midthoracic stricture, stent placement was performed with an 18-mm-diameter, 6-cm-long, silicone-covered modified Gianturco stent tube designed by Song
et al (7). The stent consisted of proximal and distal shoulders (28 mm in diameter), which were connected at right angles to the main barrel portion. The wall thickness and luminal diameter of the introducing tube were 0.8 mm and 12.0 mm, respectively. After stent placement, the patient underwent esophageal balloon dilations every 3 to 4 months for the cervical esophageal stricture over an 8-year period, whereas the stricture located at the midthoracic esophagus did not need further dilation after stent placement. The patient presented to our institution complaining of severe dysphagia to both solids and liquids. The patient was referred to interventional radiology for a trial of balloon dilation and fluoroscopic stent removal after the patient refused the only surgical option of esophagocolonojejunostomy. Esophagography showed a severe stricture at the cervical esophagus and a moderate stricture at the distal end of the stent (Figure). Given the clinical symptoms of dysphagia and the radiographic evidence of two strictures, it was decided to address both the cervical stricture and the stent-induced midthoracic stricture via balloon dilation and stent removal. Fluoroscopic balloon dilation of the stricture at the cervical esophagus was performed using a 20-mm balloon catheter. During balloon dilation, an hourglass-shaped
317
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JVIR
Figure. (a) Esophagogram prior to removal of stent placed for 8 years demonstrates strictures in the cervical (arrow) and midthoracic esophagus. Luminal narrowing is noted at the area just below the distal end of the stent (arrowhead). (b) Esophagogram at the time of stent removal demonstrates a collapsed stent being removed by a hook. Two sheaths of 9-mm (arrow) and 7-mm (arrowhead) diameter were used in stent removal. (c) Esophagogram demonstrates piece-by-piece removal of the fractured stent pieces (arrow) under both fluoroscopic and endoscopic guidance. (d) Esophagogram just after stent removal demonstrates good follow of contrast through the former site of stricture (arrowheads). (e) Esophagogram obtained 1 year after stent removal shows maintained improvement of the midthoracic stricture (arrowheads). The stricture in the cervical esophagus (arrows) shows good patency after repeated balloon dilations.
deformity of the balloon created by the stricture disappeared completely. An 0.035-inch guide wire (Radifocus M; Terumo, Tokyo, Japan) was introduced through the mouth and then across the stent into the distal portion of the esophagus. Modifying the standard stent removal protocol reported for covered retrievable stents (6,8), we used two coaxially placed sheaths for
stent removal. Initially, a 9-mm sheath was inserted past a narrowing in the proximal portion of the stent with the aid of a guiding balloon catheter. The inflation of the balloon catheter allowed passage of the 9-mm sheath across the narrowed proximal portion of the stent. The guide wire and balloon catheter were subsequently removed from the sheath and replaced
with a 7-mm sheath. Removal of the stent was performed with a 5-mm stent removal set including a hook by a previously described eversion technique (9) where the hook wire grasped the distal mesh of the stent and pulled it out in a way that caused the stent to be invaginated into itself and removed in an everted state. The stent, however, fractured during its removal.
Volume 18
Number 2
Only half of the fractured stent was removed successfully, whereas the remaining half could not be removed because of the difficulty in grasping the stent with the hook. The remaining pieces were subsequently removed piece by piece under both fluoroscopic and endoscopic guidance with a biliary biopsy forceps. The patient complained of mild pain during stent removal. Some parts of the removed stent were blood-stained, but there was no bleeding after stent removal. Although the patient underwent repeated dilations 6 to 8 months for stricture recurrence in the cervical esophagus with a 20-mm balloon catheter, the patient achieved long-term resolution of the midthoracic stricture treated with stent placement. A follow-up esophagography at 2 years after stent removal revealed maintained improvement of the midthoracic stricture.
DISCUSSION The permanent placement of esophageal stents is widely considered to be a contraindication in patients with benign strictures who have a reasonable expectation of longevity due to the high rate of late complications (4,10 – 12). The most severe complication in benign esophageal disease limiting long duration of stent placement is tissue hyperproliferation that is induced by the expansile forces exerted by the stent. Although there are conflicting reports on the timing of this complication (6,13,14), it is believed to be progressive once initiated, rendering stent removal virtually impossible because of the fears of the concomitant risks of esophageal wall perforation (14). Therefore, long-term stent placement in benign disease is generally contraindicated on the premise that excessive tissue hyperproliferation and resultant luminal obstruction would require radical surgery for stent removal. The current case is noteworthy for a number of reasons. First, it reports an unusually long duration of stent placement in a patient with an esophageal stricture. Given the relatively short life span of patients with malignant esophageal strictures and contraindication of permanent stent placement in patients with benign strictures, the results of stent placement of such
Choi et al
long-term duration have yet to be reported. Second, the current case demonstrates feasibility of stent removal after long-term placement. The concern about the necessity of surgical intervention in cases of excessive tissue hyperproliferation resulting from prolonged placement may in fact be unwarranted. The case demonstrates that stent placement of multiple-year duration may potentially be safely removed without incurring serious esophageal injury. Moreover, it also counters the belief that stents designed for permanent use cannot be removed short of surgical resection. This reports adds to the previously published cases of successful removal of other stents designed for permanent use, including the Ultraflex (Microvasive Endoscopy; Boston Scientific, Natick, Mass.) or Zesophageal stents (Wilson-Cook Medical, Winston-Salem, NC) where the stents were removed endoscopically by either grasping the proximal edge of the stent with a polyp snare or the distal edge with a rat-toothed forceps and invaginating the stent into itself (12,13,15). These methods, however, are disadvantaged by the high potential for esophageal wall injury. We therefore used two coaxially placed 9and 7-mm sheaths in stent removal where the outer 9-mm sheath served to protect the esophageal wall from injury during stent removal performed with the 7-mm sheath. More experiences will be needed to confirm the efficacy and safety of this technique. Recently, the availability of covered removable stents with a retrievable design has allowed effective and safe removal using a specifically designed retrievable hook (9). Song et al (6,8) used a stent with a drawstring attached to its upper inner margin, allowing a hook catheter to grasp and pull out the stent via the drawstring. Initial experiences with these retrievable stents inserted as a temporary measure have shown good early results (5,6). Given that the stent used in the current case lacked a retrievable feature, we used both an eversion technique with a retrievable hook and a forceps under endoscopic guidance for complete removal of the stent. A retrievable hook is very effective in securely attaching onto the mesh material of the stent, and thus using endoscopic techniques alone would have
•
319
most likely been more technically difficult. The safety and efficacy of removing stents with a retrievable hook has been described in other locations, including the gastroduodenum, rectum (9), and urethra (16). Finally, the successful results of the case point to the importance of longterm stent duration in bringing about enduring satisfactory changes in treatment-resistant corrosive strictures. Although stent placement of 8-year duration represents an extreme example, the important lesson is that a duration significantly longer than the 6- to 8-week duration advocated by previous reports (5,6) may be necessary for induction of adequate stricture remodeling in resistant cases. Early experiences with temporary stent placement have shown that premature removal of stents is associated with high relapse rates of the primary stricture, resulting in repeated procedures with additional stent placements and/or balloon dilations (6). Although an optimal time for removing a stent placed in a benign esophageal stricture is not established (5,6,14), tailoring the duration of stent placement for each patient may be the most appropriate strategy. Strictures of corrosive etiology, for instance, are notorious for being highly treatment-resistant and require relatively long periods of stent placement compared with strictures of other benign etiology. It is generally our policy to maintain a minimum duration of stent placement of at least 4 months in such resistant cases. Aside from the balloon dilation performed at the time of stent removal, the midthoracic stricture managed with stent placement never required additional treatment. In comparison, a separate stricture at the cervical esophagus required repeated balloon dilation, which continued to the time of this writing. The lack of the need for additional treatment during stent placement (ie, balloon dilation) was due to the fact that tissue hyperproliferation did not manifest as an early complication resulting in exacerbation of clinical dysphagia symptoms. The study thus suggests two important points about stent-induced tissue hyperproliferation. First, the complication may be considerably delayed in certain cases allowing for extended time for stent placement. The reason for the wide range in the rate of tissue
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•
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hyperproliferation is unclear, but we suspect that the long-term fibrotic reaction and concomitant dense scarring common in long-standing corrosive strictures may contribute to the slower rate of tissue hyperproliferation compared with strictures of other etiologies. Second, contrary to previous thought, evolutionary changes in the esophagus secondary to tissue hyperproliferation is not necessarily progressive and may stabilize after a specific time. Considering the long length of stent placement, the stricture observed at the stent ends was relatively mild and most likely resulted from tissue hyperproliferation of limited duration. Therefore, early radiographic signs of tissue hyperproliferation do not necessarily warrant immediate stent removal so long as the patient is capable of maintaining a soft-food diet and can be easily followed. In conclusion, our case indicates both the feasibility of long-term stent placement and its safe removal necessary for producing satisfactory resolution of treatment-resistant benign strictures. Although more experiences are needed, we advocate a high threshold for stent removal in cases of refractory benign esophageal strictures in order to achieve the maximal duration of stent placement needed for long-term resolution. References 1. Cwikiel W, Tranberg KG, Cwikiel M, Lillo-Gil R. Malignant dysphagia: pal-
2.
3.
4.
5.
6.
7.
8.
9.
liation with esophageal stents—longterm results in 100 patients. Radiology 1998; 207:513–518. Do YS, Song HY, Lee BH, et al. Esophagorespiratory fistula associated with esophageal cancer: treatment with a Gianturco stent tube. Radiology 1993; 187: 673– 677. Song HY, Do YS, Han YM, et al. Covered, expandable esophageal metallic stent tubes: experiences in 119 patients. Radiology 1994; 193:689 – 695. Song HY, Park SI, Do YS, et al. Expandable metallic stent placement in patients with benign esophageal strictures: results of long-term follow-up. Radiology 1997; 203:131–136. Repici A, Conio M, De Angelis C, et al. Temporary placement of an expandable polyester silicone-covered stent for treatment of refractory benign esophageal strictures. Gastrointest Endosc 2004; 60:513–519. Song HY, Jung HY, Park SI, et al. Covered retrievable expandable nitinol stents in patients with benign esophageal strictures: initial experience. Radiology 2000; 217:551–557. Song HY, Choi KC, Kwon HC, Yang DH, Cho BH, Lee ST. Esophageal strictures: treatment with a new design of modified Gianturco stent. Work in progress. Radiology 1992; 184:729 –734. Song HY, Park SI, Jung HY, et al. Benign and malignant esophageal strictures: treatment with a polyurethanecovered retrievable expandable metallic stent. Radiology 1997; 203:747–752. Yoon CJ, Shin JH, Song HY, Lim JO, Yoon HK, Sung KB. Removal of retrievable esophageal and gastrointesti-
10.
11.
12.
13.
14.
15.
16.
JVIR
nal stents: experience in 113 patients. AJR Am J Roentgenol 2004; 183:1437– 1444. Cwikiel W, Willen R, Stridbeck H, Lillo-Gil R, von Holstein CS. Self-expanding stent in the treatment of benign esophageal strictures: experimental study in pigs and presentation of clinical cases. Radiology 1993; 187:667– 671. Tan BS, Kennedy C, Morgan R, Owen W, Adam A. Using uncovered metallic endoprostheses to treat recurrent benign esophageal strictures. AJR Am J Roentgenol 1997; 169:1281–1284. Wadhwa RP, Kozarek RA, France RE, et al. Use of self-expandable metallic stents in benign GI diseases. Gastrointest Endosc 2003; 58:207–212. Fiorini A, Fleischer D, Valero J, Israeli E, Wengrower D, Goldin E. Self-expandable metal coil stents in the treatment of benign esophageal strictures refractory to conventional therapy: a case series. Gastrointest Endosc 2000; 52:259 –262. Fukuda T, Hirota S, Matsumoto S, et al. Periodic endoscopic observation of postoperative esophageal stricture due to excessive tissue hyperproliferation after stent placement. Gastrointest Endosc 2001; 53:111–114. Low DE, Kozarek RA. Removal of esophageal expandable metal stents: description of technique and review of potential applications. Surg Endosc 2003; 17:990 –996. Shin JH, Song HY, Park H, et al. Removal of retrievable self-expandable urethral stents: experience in 58 stents. Eur Radiol 2006; 16:2037–2043.