- Email: [email protected]
Rescue Retrieval of a Fully Deployed Low-Profile Intracranial Stent After Acute Occlusion
Technical Note
Rescue Retrieval of a Fully Deployed Low-Profile Intracranial Stent After Acute Occlusion Mehmet Barburoglu and Kubilay Aydin
The use of self-expandable stents for endovascular treatment of intracranial aneurysms has increased over time. Different types of stent malpositioning, such as stent migration, distortion, incomplete opening, and apposition, can occur as a complication of the stent deployment procedure. In this report, we present a successful retrieval of a low-profile stent after full deployment in a dissecting posterior-inferior cerebellar artery because of incomplete apposition and subsequent acute occlusion of the stent.
T
he use of self-expandable stents for endovascular treatment of intracranial aneurysms has increased over time. For the treatment of wide-necked aneurysms, selfexpandable intracranial stents can be deployed into the parent arteries to prevent coil protrusion, termed the stent-assisted coiling technique, or they can be used as flow-diverting devices as a stent monotherapy without coiling.1e4 All but one type of self-expandable intracranial stent (Solitaire, Covidien, Plymouth, Minnesota, USA) are not retrievable after full deployment. Here, we report the successful retrieval of a fully deployed low-profile intracranial stent after its acute occlusion in a patient with a dissecting posterior-inferior cerebellar artery (PICA) aneurysm.
CASE REPORT A 32-year-old male patient presented with severe headache and sudden weakness in his right arm and leg. His initial neurologic examination revealed right hemiparesis (grade 3/5). Cranial magnetic resonance and magnetic resonance angiography examinations demonstrated a saccular aneurysm in the left PICA. Subarachnoid hemorrhage was excluded by a negative noncontrast-enhanced cranial computed tomography and lumbar puncture. Cerebral digital subtraction angiography (DSA) was performed to evaluate the PICA aneurysm. Cerebral DSA
revealed an 8 4 mmesized, wide-necked dissecting saccular aneurysm located in the lateral medullar segment of the left PICA (Figure 1). The diameter of the medullary segment of the PICA was 1.6 mm. His hemiparesis regressed completely within 48 hours following admission. The possible treatment options were discussed with the patient. Stent monotherapy using a low-profile intracranial stent was chosen.
Procedure Dual antiplatelet therapy with 300 mg/day aspirin and 75 mg/day clopidogrel was initiated 5 days before the procedure. The proper responses to aspirin and clopidogrel were confirmed immediately before the procedure. The procedure was performed under general anesthesia. Systemic anticoagulation therapy was initiated immediately after insertion of a femoral introducer with a bolus dose of 5000 IU of heparin. A 6-Fr guiding catheter was placed into the V2 segment of the left vertebral artery. Two mg nimodipine (Nimotop, Bayer AG, Leverkusen, Germany) diluted in 150 mL saline were infused via the 6-Fr guiding catheter to prevent vasospasm. The posterior medullary segment of the left PICA was catheterized with a Headway 17 microcatheter (MicroVention, Tustin, California, USA) using a soft-tip Transend guidewire (Stryker, Fremont, California, USA) (Figure 2). A low-profile Leo baby stent (2.0 25 mm) (Balt, Montmorency, France) was deployed into the left PICA extending from the lateral medullary segment to the orifice of the PICA. The control DSA performed immediately after stent deployment showed stagnated filling of the aneurysm and incomplete opening and apposition of the stent in a very short segment (see Figure 2). An attempt of distal catheterization over the delivery wire failed. The control DSA images obtained 15 minutes after stent deployment revealed millimetric in-stent filling defects in the segment with incomplete apposition of the stent and stagnated flow in the PICA distal to the stent. Catheterization with a balloon microcatheter to perform in-stent balloon angioplasty was attempted. However, the maneuvers to catheterize this segment of the stent failed. The control DSA images that were obtained during the
Key words Aneurysms - Low-profile - Retrieval - Stents
Department of Radiology, Istanbul University Medical School, Istanbul, Turkey
Abbreviations and Acronyms DSA: Digital subtraction angiography PICA: Posterior-inferior cerebellar artery
Journal homepage: www.WORLDNEUROSURGERY.org
-
WORLD NEUROSURGERY 85: 349-352, JANUARY 2016
To whom correspondence should be addressed: Kubilay Aydin, M.D. [E-mail: [email protected]] Citation: World Neurosurg. (2016) 85:349-352. http://dx.doi.org/10.1016/j.wneu.2015.08.066
Available online: www.sciencedirect.com 1878-8750/$ - see front matter ª 2016 Elsevier Inc. All rights reserved.
www.WORLDNEUROSURGERY.org
349
TECHNICAL NOTE
Figure 1. Digital subtraction angiography (DSA) and virtual volume rendering (VRT) angiography images obtained during the initial admission procedure. (A) DSA image in the lateral oblique projection shows an 8 4 mm wide-necked aneurysm (arrow) located in the medullar segment of the left posterior-inferior cerebellar artery (PICA). (B) VRT image demonstrates the wide-necked aneurysm in the PICA. The segment of the PICA just distal to the neck of the aneurysm has a tortuous course.
attempts of distal catheterization showed progression of the stagnated in-stent flow and, eventually, complete occlusion of the stent (see Figure 2). Furthermore, there was no collateral flow to the distal PICA territory. At this time, the decision was made to remove the occluded stent to restore blood flow through the PICA. With the help of a Transend guidewire, an SL-10 microcatheter (Stryker, Fremont, California, USA) was passed through the proximal struts of the stent to catheterize the basilar artery. A 4-mm Amplatz Gooseneck microsnare loop device (Covidien, Plymouth, Minnesota, USA) was introduced to the basilar artery via its 2.3-Fr microcatheter. The tip of the SL-10 microcatheter was captured by the loop of the microsnare. Next, the SL-10 and microsnare were pulled back together to retrieve the stent from the PICA. The stent, together with the SL-microcatheter and microsnare, were pulled down into the guiding catheter. Then the entire system and the guiding catheter were pulled back and removed (Figure 3). A control DSA showed complete restoration of blood flow through the PICA and in the sac of the aneurysm (Figure 4). The procedure was completed at that point, and the patient awoke and had no deficits. Stent-assisted coiling using a shorter low-profile stent was planned but had not been performed before the submission of this paper.
DISCUSSION Parent artery occlusion, stent-assisted coiling, and flow diversion with stenting are the possible endovascular treatment options in a case of dissecting PICA aneurysm. In our case, because the aneurysm was located in the medullary segment of PICA, parent artery occlusion would cause severe neurologic deficits. Therefore stent-assisted coiling and flow diversion were the possible treatment options. When we considered the small diameter of the PICA (1.6 mm), we performed a flow diversion stent
350
www.SCIENCEDIRECT.com
monotherapy by using a low-profile stent. And we preferred a low-profile Leo baby stent, which has a relatively high-flow diversion capacity.5 Incomplete stent opening and apposition is a rare technical complication that can develop during the deployment of a selfexpandable stent. Incomplete stent apposition can lead to hemodynamic changes triggering in-stent thrombus formation and even total occlusion of the stent. In such situations, pushing and pulling manipulations of the stent delivery microcatheter inside the stent can achieve complete stent opening and apposition in most cases. Rarely, in-stent balloon angioplasty or telescopic implantation of a second stent may be required to achieve full opening and complete apposition of the stent. In our case, the parent artery had a complex anatomy, which made stent deployment challenging. The parent artery had a stenotic segment just distal to the neck of the aneurysm. Moreover, the stenotic segment of the parent artery was tortuous with steep curves and acute angles. The Leo baby stent did not fully open in this segment, probably due to a compressing effect of the tortuous anatomy of the segment.6 This technical complication eventually led to complete occlusion of the stent and PICA in our case. The medulla has a rich perforator blood supply from the medullary segments of the PICA. In our patient, occlusion of those perforators would have inevitably caused a medullar infarct.7 Furthermore, the lack of a distal collateral blood supply would have resulted in a cerebellar infarct. Thus as a bailout treatment option, we decided to retrieve the stent to restore the blood flow through the PICA. Retrieval of embolized or lost coronary stents has been described previously8; however, in the literature, there are few case reports of the intracranial stent retrieval.9e11 Mitchell et al. reported the
WORLD NEUROSURGERY, http://dx.doi.org/10.1016/j.wneu.2015.08.066
TECHNICAL NOTE
Figure 2. Digital subtraction angiography (DSA) images obtained during the endovascular procedure. (A) Roadmap DSA image in lateral projection shows the catheterization of the left PICA for stent deployment. (B and C) Angiography images obtained immediately after stent deployment reveal incomplete opening and incomplete apposition of the stent in the tortuous segment of the parent artery (arrows). (D) DSA image in lateral projection demonstrates the stagnated flow in the aneurysm sac (white arrow) and distal PICA branches (black arrows). (E) DSA image reveals total occlusion of the stent (arrows) without any collateral blood flow in the distal PICA territory.
successful removal of a deformed Pipeline flow-diverter stent using a microsnare.9 In another case report, Oh et al. described the successful retrieval of a self-expandable intracranial stent.
WORLD NEUROSURGERY 85: 349-352, JANUARY 2016
In both reports, they directly caught the proximal end of the stents using the microsnares. However, in our case, it was not possible to directly catch the stent using a microsnare because
www.WORLDNEUROSURGERY.org
351
TECHNICAL NOTE
Figure 3. Image of the retrieved stent. A microcatheter with a microguidewire is passed through the proximal struts of the stent, and a microsnare is looped around the distal tip of the microcatheter/ guidewire.
the proximal flares of the stent showed complete wall apposition. Therefore we used an indirect method to retrieve the stent. We passed through the proximal struts of the stent with a microcatheter and captured the distal end of the microcatheter by a microsnare. To our knowledge, this indirect method of stent retrieval has not been reported previously.
REFERENCES 1. Fargen KM, Hoh BL, Welch BG, Pride GL, Lanzino G, Boulos AS, et al. Long-term results of Enterprise stent-assisted coiling of cerebral aneurysms. Neurosurgery. 2012;71:239e244. 2. D’Urso PI, Lanzino G, Cloft HJ, Kallmes DF. Flow diversion for intracranial aneurysms: a review. Stroke. 2011;42:2363e2368. 3. Fiorella D, Albuquerque FC, Deshmukh VR, Woo HH, Rasmussen PA, Masaryk TJ, et al. Endovascular reconstruction with the Neuroform stent as monotherapy for the treatment of uncoilable intradural pseudoaneurysms. Neurosurgery. 2006;59:291e299. 4. Aydin K, Arat A, Sencer S, Barburoglu M, Men S. Stent-assisted coiling of wide-neck intracranial aneurysms using low-profile LEO baby stents: initial and midterm results. Am J Neuroradiol AJNR. 2015;36:1934e1941.
352
www.SCIENCEDIRECT.com
Figure 4. Digital subtraction angiography image obtained after the retrieval of the stent shows the restored flow in the posterior-inferior cerebellar artery.
In conclusion, this report confirmed that the retrieval of a fully deployed low-profile intracranial stent is possible. However, this singular case report cannot confirm the safety of this bailout treatment procedure.
5. Akmangit I, Aydin K, Sencer S, Topcuoglu OM, Topcuoglu ED, Daglioglu E, et al. Dual stenting using low-profile LEO baby stents for the endovascular management of challenging intracranial aneurysms. Am H Neuroradiol AJNR. 2015;36:323e329.
during intracranial stent intervention. 2012;7:50e53.
procedure.
Neuro-
10. Mitchell B, Lou LD, Mawad M. Retrieval of distorted pipeline embolic device using snare-loop. J Vasc Interv Neurol. 2014;7:1e4.
6. Heller RS, Malek AM. Parent vessel size and curvature strongly influence risk of incomplete stent apposition in Enterprise intracranial stent coiling. Am J Neuroradiol AJNR. 2011;32:1714e1720.
11. Chen M, Smith LG. Endovascular rescue of a misshapen intracranial stent: report of two cases. J Neurointerv Surg. 2011;3:25e26.
7. Hudgins RJ, Day AL, Quisling RG, Rhoton Jr AL, Sypert GW, Garcia-Bengochea F. Aneurysms of the posterior inferior cerebellar artery: a clinical and anatomical analysis. J Neurosurg. 1983;58:381e387.
Received: 18 July 2015; accepted: 29 August 2015
8. Eggebrecht H, Haude M, von Birgelen C, Oldenburg O, Baumgart D, Herrmann J, et al. Nonsurgical retrieval of embolized coronary stents. Catheter Cardiovasc Interv. 2000;51:432e440.
Citation: World Neurosurg. (2016) 85:349-352. http://dx.doi.org/10.1016/j.wneu.2015.08.066
9. Oh Y, Hwang DH, Ko YH, Kang IW, Kim IS, Hur CW. Foreign body removal by snare loop:
1878-8750/$ - see front matter ª 2016 Elsevier Inc. All rights reserved.
Journal homepage: www.WORLDNEUROSURGERY.org Available online: www.sciencedirect.com
WORLD NEUROSURGERY, http://dx.doi.org/10.1016/j.wneu.2015.08.066
Rescue Retrieval of a Fully Deployed Low-Profile Intracranial Stent After Acute Occlusion Mehmet Barburoglu and Kubilay Aydin
The use of self-expandable stents for endovascular treatment of intracranial aneurysms has increased over time. Different types of stent malpositioning, such as stent migration, distortion, incomplete opening, and apposition, can occur as a complication of the stent deployment procedure. In this report, we present a successful retrieval of a low-profile stent after full deployment in a dissecting posterior-inferior cerebellar artery because of incomplete apposition and subsequent acute occlusion of the stent.
T
he use of self-expandable stents for endovascular treatment of intracranial aneurysms has increased over time. For the treatment of wide-necked aneurysms, selfexpandable intracranial stents can be deployed into the parent arteries to prevent coil protrusion, termed the stent-assisted coiling technique, or they can be used as flow-diverting devices as a stent monotherapy without coiling.1e4 All but one type of self-expandable intracranial stent (Solitaire, Covidien, Plymouth, Minnesota, USA) are not retrievable after full deployment. Here, we report the successful retrieval of a fully deployed low-profile intracranial stent after its acute occlusion in a patient with a dissecting posterior-inferior cerebellar artery (PICA) aneurysm.
CASE REPORT A 32-year-old male patient presented with severe headache and sudden weakness in his right arm and leg. His initial neurologic examination revealed right hemiparesis (grade 3/5). Cranial magnetic resonance and magnetic resonance angiography examinations demonstrated a saccular aneurysm in the left PICA. Subarachnoid hemorrhage was excluded by a negative noncontrast-enhanced cranial computed tomography and lumbar puncture. Cerebral digital subtraction angiography (DSA) was performed to evaluate the PICA aneurysm. Cerebral DSA
revealed an 8 4 mmesized, wide-necked dissecting saccular aneurysm located in the lateral medullar segment of the left PICA (Figure 1). The diameter of the medullary segment of the PICA was 1.6 mm. His hemiparesis regressed completely within 48 hours following admission. The possible treatment options were discussed with the patient. Stent monotherapy using a low-profile intracranial stent was chosen.
Procedure Dual antiplatelet therapy with 300 mg/day aspirin and 75 mg/day clopidogrel was initiated 5 days before the procedure. The proper responses to aspirin and clopidogrel were confirmed immediately before the procedure. The procedure was performed under general anesthesia. Systemic anticoagulation therapy was initiated immediately after insertion of a femoral introducer with a bolus dose of 5000 IU of heparin. A 6-Fr guiding catheter was placed into the V2 segment of the left vertebral artery. Two mg nimodipine (Nimotop, Bayer AG, Leverkusen, Germany) diluted in 150 mL saline were infused via the 6-Fr guiding catheter to prevent vasospasm. The posterior medullary segment of the left PICA was catheterized with a Headway 17 microcatheter (MicroVention, Tustin, California, USA) using a soft-tip Transend guidewire (Stryker, Fremont, California, USA) (Figure 2). A low-profile Leo baby stent (2.0 25 mm) (Balt, Montmorency, France) was deployed into the left PICA extending from the lateral medullary segment to the orifice of the PICA. The control DSA performed immediately after stent deployment showed stagnated filling of the aneurysm and incomplete opening and apposition of the stent in a very short segment (see Figure 2). An attempt of distal catheterization over the delivery wire failed. The control DSA images obtained 15 minutes after stent deployment revealed millimetric in-stent filling defects in the segment with incomplete apposition of the stent and stagnated flow in the PICA distal to the stent. Catheterization with a balloon microcatheter to perform in-stent balloon angioplasty was attempted. However, the maneuvers to catheterize this segment of the stent failed. The control DSA images that were obtained during the
Key words Aneurysms - Low-profile - Retrieval - Stents
Department of Radiology, Istanbul University Medical School, Istanbul, Turkey
Abbreviations and Acronyms DSA: Digital subtraction angiography PICA: Posterior-inferior cerebellar artery
Journal homepage: www.WORLDNEUROSURGERY.org
-
WORLD NEUROSURGERY 85: 349-352, JANUARY 2016
To whom correspondence should be addressed: Kubilay Aydin, M.D. [E-mail: [email protected]] Citation: World Neurosurg. (2016) 85:349-352. http://dx.doi.org/10.1016/j.wneu.2015.08.066
Available online: www.sciencedirect.com 1878-8750/$ - see front matter ª 2016 Elsevier Inc. All rights reserved.
www.WORLDNEUROSURGERY.org
349
TECHNICAL NOTE
Figure 1. Digital subtraction angiography (DSA) and virtual volume rendering (VRT) angiography images obtained during the initial admission procedure. (A) DSA image in the lateral oblique projection shows an 8 4 mm wide-necked aneurysm (arrow) located in the medullar segment of the left posterior-inferior cerebellar artery (PICA). (B) VRT image demonstrates the wide-necked aneurysm in the PICA. The segment of the PICA just distal to the neck of the aneurysm has a tortuous course.
attempts of distal catheterization showed progression of the stagnated in-stent flow and, eventually, complete occlusion of the stent (see Figure 2). Furthermore, there was no collateral flow to the distal PICA territory. At this time, the decision was made to remove the occluded stent to restore blood flow through the PICA. With the help of a Transend guidewire, an SL-10 microcatheter (Stryker, Fremont, California, USA) was passed through the proximal struts of the stent to catheterize the basilar artery. A 4-mm Amplatz Gooseneck microsnare loop device (Covidien, Plymouth, Minnesota, USA) was introduced to the basilar artery via its 2.3-Fr microcatheter. The tip of the SL-10 microcatheter was captured by the loop of the microsnare. Next, the SL-10 and microsnare were pulled back together to retrieve the stent from the PICA. The stent, together with the SL-microcatheter and microsnare, were pulled down into the guiding catheter. Then the entire system and the guiding catheter were pulled back and removed (Figure 3). A control DSA showed complete restoration of blood flow through the PICA and in the sac of the aneurysm (Figure 4). The procedure was completed at that point, and the patient awoke and had no deficits. Stent-assisted coiling using a shorter low-profile stent was planned but had not been performed before the submission of this paper.
DISCUSSION Parent artery occlusion, stent-assisted coiling, and flow diversion with stenting are the possible endovascular treatment options in a case of dissecting PICA aneurysm. In our case, because the aneurysm was located in the medullary segment of PICA, parent artery occlusion would cause severe neurologic deficits. Therefore stent-assisted coiling and flow diversion were the possible treatment options. When we considered the small diameter of the PICA (1.6 mm), we performed a flow diversion stent
350
www.SCIENCEDIRECT.com
monotherapy by using a low-profile stent. And we preferred a low-profile Leo baby stent, which has a relatively high-flow diversion capacity.5 Incomplete stent opening and apposition is a rare technical complication that can develop during the deployment of a selfexpandable stent. Incomplete stent apposition can lead to hemodynamic changes triggering in-stent thrombus formation and even total occlusion of the stent. In such situations, pushing and pulling manipulations of the stent delivery microcatheter inside the stent can achieve complete stent opening and apposition in most cases. Rarely, in-stent balloon angioplasty or telescopic implantation of a second stent may be required to achieve full opening and complete apposition of the stent. In our case, the parent artery had a complex anatomy, which made stent deployment challenging. The parent artery had a stenotic segment just distal to the neck of the aneurysm. Moreover, the stenotic segment of the parent artery was tortuous with steep curves and acute angles. The Leo baby stent did not fully open in this segment, probably due to a compressing effect of the tortuous anatomy of the segment.6 This technical complication eventually led to complete occlusion of the stent and PICA in our case. The medulla has a rich perforator blood supply from the medullary segments of the PICA. In our patient, occlusion of those perforators would have inevitably caused a medullar infarct.7 Furthermore, the lack of a distal collateral blood supply would have resulted in a cerebellar infarct. Thus as a bailout treatment option, we decided to retrieve the stent to restore the blood flow through the PICA. Retrieval of embolized or lost coronary stents has been described previously8; however, in the literature, there are few case reports of the intracranial stent retrieval.9e11 Mitchell et al. reported the
WORLD NEUROSURGERY, http://dx.doi.org/10.1016/j.wneu.2015.08.066
TECHNICAL NOTE
Figure 2. Digital subtraction angiography (DSA) images obtained during the endovascular procedure. (A) Roadmap DSA image in lateral projection shows the catheterization of the left PICA for stent deployment. (B and C) Angiography images obtained immediately after stent deployment reveal incomplete opening and incomplete apposition of the stent in the tortuous segment of the parent artery (arrows). (D) DSA image in lateral projection demonstrates the stagnated flow in the aneurysm sac (white arrow) and distal PICA branches (black arrows). (E) DSA image reveals total occlusion of the stent (arrows) without any collateral blood flow in the distal PICA territory.
successful removal of a deformed Pipeline flow-diverter stent using a microsnare.9 In another case report, Oh et al. described the successful retrieval of a self-expandable intracranial stent.
WORLD NEUROSURGERY 85: 349-352, JANUARY 2016
In both reports, they directly caught the proximal end of the stents using the microsnares. However, in our case, it was not possible to directly catch the stent using a microsnare because
www.WORLDNEUROSURGERY.org
351
TECHNICAL NOTE
Figure 3. Image of the retrieved stent. A microcatheter with a microguidewire is passed through the proximal struts of the stent, and a microsnare is looped around the distal tip of the microcatheter/ guidewire.
the proximal flares of the stent showed complete wall apposition. Therefore we used an indirect method to retrieve the stent. We passed through the proximal struts of the stent with a microcatheter and captured the distal end of the microcatheter by a microsnare. To our knowledge, this indirect method of stent retrieval has not been reported previously.
REFERENCES 1. Fargen KM, Hoh BL, Welch BG, Pride GL, Lanzino G, Boulos AS, et al. Long-term results of Enterprise stent-assisted coiling of cerebral aneurysms. Neurosurgery. 2012;71:239e244. 2. D’Urso PI, Lanzino G, Cloft HJ, Kallmes DF. Flow diversion for intracranial aneurysms: a review. Stroke. 2011;42:2363e2368. 3. Fiorella D, Albuquerque FC, Deshmukh VR, Woo HH, Rasmussen PA, Masaryk TJ, et al. Endovascular reconstruction with the Neuroform stent as monotherapy for the treatment of uncoilable intradural pseudoaneurysms. Neurosurgery. 2006;59:291e299. 4. Aydin K, Arat A, Sencer S, Barburoglu M, Men S. Stent-assisted coiling of wide-neck intracranial aneurysms using low-profile LEO baby stents: initial and midterm results. Am J Neuroradiol AJNR. 2015;36:1934e1941.
352
www.SCIENCEDIRECT.com
Figure 4. Digital subtraction angiography image obtained after the retrieval of the stent shows the restored flow in the posterior-inferior cerebellar artery.
In conclusion, this report confirmed that the retrieval of a fully deployed low-profile intracranial stent is possible. However, this singular case report cannot confirm the safety of this bailout treatment procedure.
5. Akmangit I, Aydin K, Sencer S, Topcuoglu OM, Topcuoglu ED, Daglioglu E, et al. Dual stenting using low-profile LEO baby stents for the endovascular management of challenging intracranial aneurysms. Am H Neuroradiol AJNR. 2015;36:323e329.
during intracranial stent intervention. 2012;7:50e53.
procedure.
Neuro-
10. Mitchell B, Lou LD, Mawad M. Retrieval of distorted pipeline embolic device using snare-loop. J Vasc Interv Neurol. 2014;7:1e4.
6. Heller RS, Malek AM. Parent vessel size and curvature strongly influence risk of incomplete stent apposition in Enterprise intracranial stent coiling. Am J Neuroradiol AJNR. 2011;32:1714e1720.
11. Chen M, Smith LG. Endovascular rescue of a misshapen intracranial stent: report of two cases. J Neurointerv Surg. 2011;3:25e26.
7. Hudgins RJ, Day AL, Quisling RG, Rhoton Jr AL, Sypert GW, Garcia-Bengochea F. Aneurysms of the posterior inferior cerebellar artery: a clinical and anatomical analysis. J Neurosurg. 1983;58:381e387.
Received: 18 July 2015; accepted: 29 August 2015
8. Eggebrecht H, Haude M, von Birgelen C, Oldenburg O, Baumgart D, Herrmann J, et al. Nonsurgical retrieval of embolized coronary stents. Catheter Cardiovasc Interv. 2000;51:432e440.
Citation: World Neurosurg. (2016) 85:349-352. http://dx.doi.org/10.1016/j.wneu.2015.08.066
9. Oh Y, Hwang DH, Ko YH, Kang IW, Kim IS, Hur CW. Foreign body removal by snare loop:
1878-8750/$ - see front matter ª 2016 Elsevier Inc. All rights reserved.
Journal homepage: www.WORLDNEUROSURGERY.org Available online: www.sciencedirect.com
WORLD NEUROSURGERY, http://dx.doi.org/10.1016/j.wneu.2015.08.066