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Pma/510(k) # = k163468.(b)(4).Problem statement: ct is disintegrating after 6 months.Stent placed at another hospital on ct is disintegrating after 6 months.This was not an immediate problem it occurred 6 months afterwards the top of the stent has completely broken up with a few wire strands remaining and was exceptionally difficult to intubate with the guide wire without passing outside the interstices.Patient had instant and massive improvement from the secondary stent, confirmed on contrast study and was discharged after a big breakfast the next day.Device evaluation: the evo-22-27-9-d device of lot number c1296589 was implanted in the patient and is therefore unavailable for evaluation.With the information provided a document based investigation was carried out.The following additional information was requested by the cook representative and the responses were received as below: 1.1.1 was the wire guide flushed and kept wet during use? unknown; 1.1.2 what was used to flush the wire guide (for example: water, saline, contrast, etc.)?unknown; 1.1.3 what are the reorder numbers of all accessories advanced over the wire guide?evo-22-27-9-d; 1.1.4 if not, with the device in question, how was the procedure finished? this was a delayed problem 6 months post stenting another stent was placed through the fractured stent; 1.2 for complaints occurring during use (once in contact with endoscope) also ask:; 1.2.1 what is the endoscope manufacturer and model number that was used? unknown 1.2.2 please describe the location in the body where the wire guide was placed.Duodenum; 1.2.3 how many exchanges were completed with this wire guide? n/a; 1.2.4 for procedures involving sphincterotomy/ercp, was the wire guide left in place; during electrosurgical current application? n/a; 1.2.5 did any section of the device detach inside the endoscope or patient? no only stent left in situ.A section of the device did remain inside the patient¿s body.Stent designed to be left in situ patient restented through old stent.The patient did require any additional procedures due to this occurrence.Patient required restenting as the first stent was breaking up 6 months after implant.According to the initial reporter, the patient did experience any adverse effects due to this occurrence.Abdominal pain and weight loss.Images were provided to support the complaint investigation.They were reviewed through cook research inc.And the following comments were provided by the independent reviewer: findings: pdf file containing multiple powerpoint images of an endoscopy, ct scans and fluoroscopy, along with the complaint report, were submitted for review.Initial fluoroscopic images demonstrate an endoscope placed in the distal duodenum.An evolution duodenal controlled-release uncovered stent measuring 22 mm in diameter and 9 cm in length was deployed across an area of severe stenosis, as is demonstrated by deformation of the midportion of the stent body.There is severe tapering of the midportion of the stent body.The distal portion of the stent appears unremarkable while the proximal portion is difficult to evaluate due to underpenetration.Selected images from a follow-up ct scan, dated (b)(6) 2018, in both axial and coronal reformats, demonstrate the duodenal stent in place.There is no evidence of distention of the stomach.There is no obvious stent fracture.There is a small amount of ascites seen throughout the abdomen and pelvis.Selected images from a follow-up ct scan, dated (b)(6) 2018, with both axial and coronal reformats submitted, demonstrate significant irregularity involving the proximal portion of the stent, consistent with stent fracture.There are multiple metallic fragments which appear somewhat disorganized along the proximal margin of the stent, extending into the stomach.The stomach is not distended.There is interval increase in the amount of ascites throughout the abdomen and pelvis and progressive abnormal thickening in the region of the distal gastric/duodenal malignancy.Endoscopic and fluoroscopic images from (b)(6) 2018 demonstrate complete unraveling of the proximal portion of the evolution duodenal stent.On the endoscopic images there are several metallic tines seen in the distal stomach, not in an organized configuration.It is uncertain if these tines project entirely through the wall of the stomach at this point.Per the report, the patient had several weeks of increasing symptoms of unable to retain food with abdominal pain and weight loss.Eventually, the lumen of the stent was negotiated through and a 24 mm covered egis stent was placed through the existing evolution duodenal stent.Final fluoroscopic evaluation demonstrates contrast extending into the newly placed stent.Impression: initial endoscopy and stent placement were performed for a gastric outlet obstruction due to underlying malignancy.Initial fluoroscopic images demonstrated placement of an evolution duodenal stent, extending from the antrum of the stomach into the proximal duodenum across the area of severe stenosis.Initial follow-up ct scan performed 3 months after implantation demonstrated the stent to be in stable position without evidence of distracted fracture or malfunction.Patient had no reported symptoms at the time of this imaging.Follow-up ct scan 3 months later, obtained in (b)(6) 2018, demonstrates very abnormal appearance to the proximal portion of the stent, which appears disorganized due to stent lattice fracture and partial migration of multiple metallic fragments.There is increased abdominal ascites as well as progressive malignant thickening of the distal stomach and duodenum, consistent with progressive disease.There are no comments on the images or in the complaint report regarding any symptoms at this point, despite the abnormal appearance of the stent.The cause of stent fracture is indeterminate, but likely multifactorial and related to the long dwell time and constant peristalsis experienced from the proximal margin of the stent extending into the normal distal portion of the stomach across the severe stenosis.There may also be a component of increased tumor ingrowth, as the overall abnormal thickening seen throughout this region appears progressive when compared to prior, resulting in elements of the stent behaving more fixed, therefore increasing the forces placed on the proximal margin of the stent from stomach peristalsis.The evolution duodenal stent is intended for palliative use, as stated in the ifu, and typically patients do not live a long time with their disease which limits the chance of them experiencing any malfunctions of the stent.Unfortunately, the patient did develop symptoms in (b)(6) 2018 consistent with abdominal pain, weight loss and unable to retain food, findings consistent with progressive gastric outlet obstruction, likely due to stent malfunction but also due to tumor progression.This was treated with repeat endoscopy and placement of a covered stent through the existing evolution duodenal stent with final fluoroscopic image demonstrating contrast extending through the new covered stent.If the patient¿s life expectancy was known to be this long, a better approach would have been the creation of a gastrojejunostomy as it is a more durable option.However, hindsight is 20/20, and the initial life expectancy may have been only on the order of months, therefore the use of an endoscopic duodenal stent appeared more appropriate at the time.The following comments were also made: progressive malignant gastric outlet obstruction, potentially causing significant tumor ingrowth of the stent, resulting in fixation of the stent and therefore increasing the repetitive forces caused by gastric peristalsis, resulting in stent fracture.Dwell time of >9 months, contributing to development of stent fracture from repetitive stresses of peristalsis.Root cause: the cause of stent fracture is indeterminate, but likely multifactorial and related to the long dwell time and constant peristalsis experienced from the proximal margin of the stent extending into the normal distal portion of the stomach across the severe stenosis.There may also be a component of increased tumor ingrowth, as the overall abnormal thickening seen throughout this region appears progressive when compared to prior, resulting in elements of the stent behaving more fixed, therefore increasing the forces placed on the proximal margin of the stent from stomach peristalsis.The complaint is confirmed as the failure was verified in the images.Significant irregularity involving the proximal portion of the stent, consistent with stent fracture.There are multiple metallic fragments which appear somewhat disorganized along the proximal margin of the stent, extending into the stomach.Document review: prior to distribution all evo-22-27-9-devices are subjected to a visual inspection and functional checks to ensure device integrity.These inspections and functional checks are outlined in internal procedures in place at cirl.A review of the qc records c1296589 did not reveal any issues which could have contributed to this complaint issue.Upon review of complaints, this failure mode has not occurred previously with the lot number c1296589.Based on the information available to date, there is no evidence to suggest that there are any manufacturing issues associated with the lot number c1296589.Ifu review: it may be noted that as per the instructions for use, long term patency of this device has not been established and this stent is designed for palliative care.As per the instructions for use, which accompanies this device instructs the user to "visually inspect with particular attention to kinks, bends and breaks.If an abnormality is detected that would prohibit proper working condition, do not use".Summary: the complaint is confirmed as the failure was verified in the images.Significant irregularity involving the proximal portion of the stent, consistent with stent fracture.There are multiple metallic fragments which appear somewhat disorganized along the proximal margin of the stent, extending into the stomach.From the information provided, there have been no adverse effects to the patient as a result of this occurrence.Complaints of this nature will continue to be monitored for potential emerging trends.
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