[Orbital firearm injuries]. / Orbitale Schussverletzungen.

BACKGROUND: Injuries caused by firearms are fortunately rare in the field of ophthalmology. The treatment of an affected patient is a special challenge both ophthalmologically and emotionally. METHODS: We report on seven consecutive cases of patients with an orbital gunshot injury who presented in a university hospital over a period of 11 years. The course of events leading to the injury with the weapon involved, the type of projectile, the injury pattern, cranial imaging, treatment and course were evaluated. RESULTS: A total of seven cases of injuries caused by firearms could be documented and evaluated in the period 2007-2018. All seven patients were male. The average age was 44 ± 27.5 years. Of the injuries five were caused by a suicide attempt and two by an accident. Firearms were used except for one injury caused by a crossbow. There was a retained projectile in four of the cases, the bullet went through the body in two cases and one of the cases presented with a ricochet shot. The final visual acuity was unilateral amaurosis in 1 case and bilateral amaurosis in another case, 1/35 (measured at 1 m) in 1 case, while it varied between 0.2 and 0.7 in the other 4 cases. No patient died as a direct consequence of the firearm injury. CONCLUSION: Injuries caused by firearms are relatively rare in Germany and mostly have a suicidal background. The pattern of the injury of the ocular structures is very variable. A reconstruction attempt is principally recommended. In the care of patients interdisciplinary cooperation between ophthalmologists and neurosurgeons, orofacial surgeons, ear nose and throat (ENT) surgeons and psychiatrists is necessary.

[Intraoperative optical coherence tomography in explorative vitrectomy in patients with vitreous haemorrhage-a case series]. / Intraoperative optische Kohärenztomographie bei explorativer Vitrektomie an Patienten mit Glaskörperblutung ­ eine Fallserie.

BACKGROUND: High-resolution spectral domain optical coherence tomography (SD-OCT) is a gold standard technique for diagnosis, management and monitoring of patients with vitreoretinal diseases. Preoperative diagnostics for evaluation of intraocular and retinal status in patients with vitreous haemorrhage are limited, thus final therapeutic decisions can only be made during explorative vitrectomy. We evaluated the use of intraoperative SD-OCT (iSD-OCT) as a real-time additional diagnostic tool during explorative vitrectomy in patients with vitreous haemorrhage. METHODS: We report on 9 patients (11 eyes) with vitreous haemorrhage. Preoperative ultrasound was performed to evaluate intraocular status. Subsequently, an explorative 23G pars plana vitrectomy was performed under visualisation with the OPMI Lumera 700 surgical microscope (Carl Zeiss Meditec, Jena, Germany) equipped with a fully integrated iSD-OCT device (Rescan 700, Carl Zeiss Meditec, Jena, Germany) as a real-time diagnostic tool. RESULTS: In all patients, intraoperative iSD-OCT allowed real-time evaluation of the preretinal, intraretinal and subretinal structures in addition to the intraoperative en face image. The further surgical strategy, i. e. necessity for peeling of epiretinal membranes (ERM) or of the inner limiting membrane (ILM), application of intravitreal medication and selection of the appropriate tamponade, was based on and optimised according to the iSD-OCT images. CONCLUSION: Intraoperative iSD-OCT is highly useful as an additional intraoperative diagnostic tool in patients with vitreous haemorrhage. In addition to the en face microscope image, it facilitates intraoperative real-time diagnosis and aids therapeutic decision-making during surgery.

[Vitrectomy and iOCT-assisted inverted ILM flap technique in patients with full thickness macular holes]. / Vitrektomie mit iOCT-assistierter invertierter ILM-Flap-Technik bei großen Makulaforamina.

BACKGROUND: In large full thickness macular holes (FTMH) the closure rate after vitrectomy and conventional internal limiting membrane (ILM) peeling is less than 90%. The aim of this study was to examine the visual acuity and anatomical success rate with high-resolution optical coherence tomography (OCT) after transconjunctival sutureless 23-gauge pars plana vitrectomy as well as intraoperative OCT (iOCT) and Brilliant Peel (BP)-assisted ILM peeling using the inverted ILM flap technique in patients with large FTMHs. METHOD: In this retrospective study 25 eyes of 25 consecutive patients with large FTMH were treated by 23-G vitrectomy with BP and iOCT-assisted ILM peeling using the inverted ILM flap technique followed by gas tamponade. In all patients best corrected visual acuity (BCVA) and the maximum diameter, base and height of the FTMH as well as intraretinal alterations were measured preoperatively using high-resolution spectral domain OCT (SD-OCT, Spectralis, Heidelberg Engineering, Germany). The BCVA was measured after 1, 3, and 6 months. Additionally, the closure rate and the microstructural integrity of the outer retinal layers, e.g. external limiting membrane (ELM), ellipsoid zone und photoreceptor outer segment (OS) were registered in the SD-OCT and correlated with the results of BCVA after macular hole surgery. RESULTS: In all surgical procedures with the inverted ILM flap technique the application of iOCT enabled a good visualization and a controlled positioning of the ILM flaps. At baseline mean BCVA was 0.2 (0.7 logMAR) and improved significantly after 1, 3 und 6 months to 0.4 (0.4 logMAR), 0.5 (0.3 logMAR) and 0.63 (0.2 logMAR), respectively. The closure rate of the FTMHs was 100%. Microstructural integrity of the outer retinal layers was evaluated semiquantitatively and showed good correlation with BCVA. CONCLUSION: Vitrectomy with BP and iOCT-assisted ILM peeling using the inverted ILM flap technique in patients with large FTMH is a very controlled and safe microsurgical strategy and shows good functional and anatomical results. The morphology of the FTMH, the ILM flap and the position of the inverted ILM flap under air was well visualized by IOCT. The microstructural integrity of the outer retinal layers is displayed in detail on SD-OCT and represents an important predictive parameter for BCVA after macular hole surgery.

Primary precutting versus conventional over-the-wire sphincterotomy for bile duct access: a prospective randomized study.

BACKGROUND AND STUDY AIMS: Precut is a well-known technique that is used if repeated attempts at common bile duct (CBD) cannulation fail. Opinions on the complication rate of precut are conflicting, however. The aim of the present study was to compare the efficacy and complication rate of precut used as a primary method of CBD access with the efficacy and safety of the conventional technique. PATIENTS AND METHODS: During the 19-month study period, consecutive patients who were scheduled for first-time endoscopic sphincterotomy (ES) for a variety of biliary disorders were randomized into two groups: patients in group A underwent conventional wire-guided biliary cannulation followed by ES (with precut being performed only when this failed); in patients in group B precut was used as a primary technique to gain biliary access, followed by wire-guided ES. We used a specially designed, modified Erlangen type of sphincterotome for precutting. RESULTS: A total of 291 patients (100 men, 191 women; mean +/- SD age 65 +/- 17.5 years) were recruited: 146 patients were assigned to group A (conventional approach) and 145 to group B (primary precut approach). The indications for ES were comparable in the two groups. In group A, wire-guided cannulation of the CBD failed in 42 patients. Secondary precut was successful in 41 of these patients, leading to an overall success rate of 99.3 %. In group B, the ES success rate using primary precut was 100 % at the first attempt. The mean time to successful deep CBD cannulation was 8.3 +/- 2.1 minutes in group A and 6.9 +/- 1.8 minutes in group B ( P < 0.001). The incidence of mild to moderate pancreatitis was similar in the two groups (2.9 % in group A vs. 2.1 % in group B, P > 0.05). Mild bleeding occurred in only one patient (from group A) and this was controlled by epinephrine injection. None of the study patients developed severe pancreatitis or perforation. CONCLUSIONS: In experienced hands, an approach using primary precut appears to be at least as successful and safe as a conventional approach using guide-wire-based CBD cannulation followed by ES, and might also be a quicker method.

Endoscopic resection of benign tumors of the papilla of vater.

Most benign papillary tumors are adenomas which can potentially undergo the adenoma-carcinoma-sequence making complete removal mandatory for curative therapy. Endoscopic resection (papillectomy) of these lesions is being increasingly performed as a less traumatic alternative to surgery. Available data shows endoscopic papillectomy to be effective and safe in experienced hands with usually little morbidity and virtually no mortality. Success rates are around 80 % for lesions without intraductal involvement. Selected cases of limited distal intraductal involvement accessible after sphincterotomy may also be managed curatively by endoscopic resection. Endoscopic snare resection of entire lesions should be primarily regarded as a diagnostic procedure. It allows for an accurate histological diagnosis based on examination of the entire specimen rather than forceps biopsies and thus a reliable assessment of the need for surgical therapy. Subsequent surgery in operable patients is not precluded by previous endoscopic resection. Surgery is indicated in case of incomplete removal and if malignancy is present. The curative role of endoscopic papillectomy for early invasive carcinoma needs to be established. Histological features and individual risk for surgery are factors to be considered. Inoperable patients may still benefit from palliative endoscopic stenting. After endoscopic papillectomy has been completed, regular follow-up examinations including biopsies are warranted because of the risk of local recurrence. For benign looking papillary tumors, endoscopic papillectomy serves as a diagnostic tool and should be considered as first line procedure regardless of age. The following article details the approach to patients with benign papillary tumor and the technique of endoscopic papillectomy.

Is endoscopic polypectomy an adequate therapy for malignant colorectal adenomas? Presentation of 114 patients and review of the literature.

PURPOSE: This study was designed to evaluate the outcome of endoscopic polypectomy of malignant polyps with and without subsequent surgery based on histologic criteria. METHODS: Consecutive patients with invasive carcinoma in colorectal polyps endoscopically removed between 1985 and 1996 were retrospectively studied. Patients with complete resection, grading G1 or G2, and absence of vascular invasion were classified as "low risk." The other patients were classified "high risk." Available literature was reviewed by applying similar classification criteria. RESULTS: A total of 114 patients (59 males; median age, 70 (range, 20-92) years) were included. Median polyp size was 2.5 (0.4-10) cm. After polypectomy, of 54 patients with low-risk malignant polyps, 13 died of unrelated causes after a median of 76 months, 5 had no residual tumor at surgery, and 33 were alive and well during a median follow-up of 69 (range, 9-169) months. Of 60 patients with high-risk malignant polyps, 52 had surgery (residual carcinoma 27 percent). Five of eight patients not operated had an uneventful follow-up of median 57 (range, 47-129) months. Patients in the high-risk group were significantly more likely to have an adverse outcome than those in the low-risk group (P < 0.0001). Review of 20 studies including 1,220 patients with malignant polyps revealed no patient with low-risk criteria with an adverse outcome. CONCLUSIONS: For patients with low-risk malignant polyps, endoscopic polypectomy alone seems to be adequate. In high-risk patients, the risk of adverse outcome should be weighed against the risk of surgery.

Long-term results of endoscopic removal of large colorectal adenomas.

BACKGROUND AND STUDY AIMS: Endoscopic removal of large colorectal polyps has not been widely accepted. The aims of this study were to evaluate our longterm experiences justifying endoscopic resection technique as the treatment of choice. PATIENTS AND METHODS: During a period of 12 years, 288 patients with a total of 302 polyps larger than 3 cm in diameter were treated endoscopically. 224 polyps were sessile and 78 pedunculated. Sessile polyps were removed using the piecemeal technique. Surgery was recommended in patients with unfavorable histology. Patients with favorable histology were followed up at 3 - 6 month intervals in the first year and then every 1 - 2 years. RESULTS: A total of 184 patients with sessile polyps were followed up for at least 6 months. Recurrence rate of 166 benign polyps was 17 % (29/166). Only two patients had malignant recurrence. 8 of 18 patients with malignant polyps underwent surgery while 10 were unfit for surgery. 8 of these patients remained free of recurrence. CONCLUSIONS: Previous concerns about endoscopic removal of large colorectal polyps are no longer justified. The results of this study showed that endoscopic resection of large colorectal polyps is safe and effective. In patients with high operative risk, endoscopic removal may be adequate.

Impact of endoscopic ultrasound for evaluation of submucosal lesions in gastrointestinal tract.

BACKGROUND: Endoscopic ultrasound is widely used following endoscopy for evaluation of suspected submucosal lesions and may guide further management of patients. PATIENTS AND METHOD: A total of 181 consecutive patients with suspected submucosal lesion in the upper gastrointestinal tract were diagnosed by endoscopic ultrasound between 1990-97. We evaluated: 1) the potential of endoscopic ultrasound criteria to predict histological type of submucosal lesions in 69 patients with available histology, 2) the ability of endoscopic ultrasound alone or with clinical presentation, to predict malignancy in 86 patients with available histology or follow-up of >12 months. RESULTS: Sensitivity and specificity for diagnosing 44 gastrointestinal stromal tumours were 95 and 72%, respectively, while 25 miscellaneous lesions were diagnosed correctly in only 56% by endoscopic ultrasound. Diagnosis of malignancy, using any two of three endoscopic ultrasound criteria (heterogeneous echotexture, size >3 cm, irregular margins) showed a sensitivity of 80% and specificity of 77%, giving accurate endoscopic ultrasound diagnosis in 16/20 malignant and 51/66 benign submucosal lesion. Heterogeneous echotexture, size >3 cm, and irregular margins showed a relative risk of 7.2, 5.4 and 4.6, respectively, for presence of malignancy. The presence of symptoms, potentially suggesting malignancy (dysphagia, gastrointestinal bleeding, pain and weight loss), had a relative risk of 4.2, however this did not increase the accuracy of diagnosing malignancy based on endoscopic ultrasound criteria alone. CONCLUSION: The accuracy of endoultrasound is high in diagnosing gastrointestinal stromal tumours, which show a significant potential of malignancy. Endoscopic ultrasound morphology appears to be helpful in selection of patients for surgical or conservative treatment. The accuracy of endoscopic ultrasound in differential diagnosis of non-gastrointestinal stromal tumour lesions is limited.

First in vivo optical coherence tomography in the human bile duct.

BACKGROUND AND STUDY AIMS: Optical coherence tomography (OCT) is a novel technique for performing high-resolution, cross-sectional tomographic imaging in human tissue, which allows resolution of up to 10 microm. The short depth of penetration allows assessment of the superficial 2 mm of the gastrointestinal tract, an area that is difficult to appraise even with high-frequency ultrasound. This is the first report on in vivo OCT of the human biliary system. The aim was to assess the feasibility of the technique. PATIENTS AND METHODS: Four cases of intraductal OCT are presented. The probe was inserted through the working channel of a duodenoscope. RESULTS: The connective tissue layer and the underlying retroperitoneal tissue, with less backscattering, could be clearly demonstrated. The images showed a layer architecture which was similar to that found histologically. CONCLUSIONS: OCT of the biliary system is feasible in patients with biliary pathology. Interpretable images were obtained, and clinical use needs further assessment. As current OCT probes and processors do not yet provide optimal resolution, further generations of equipment with improved image quality are required.

Outcome of endoscopic sphincterotomy in patients with pain of suspected biliary or papillary origin and inconclusive cholangiography findings.

BACKGROUND AND STUDY AIMS: We prospectively studied the outcome of endoscopic sphincterotomy in symptomatic patients with elevated liver enzyme levels but no clear evidence of biliary pathology on transabdominal ultrasound and diagnostic endoscopic retrograde cholangiography (ERC). METHODS: 29 consecutive patients with biliary-type pain (two or more out of eight criteria), elevated liver enzyme levels and no evidence of gallstones or significant common bile duct dilatation were evaluated. Elevated bilirubin levels (up to 7.2 mg/dl) were found in 18 patients. The majority of patients (n = 21) had a gallbladder in situ. The findings from bile duct exploration following sphincterotomy were recorded, and pain (as measured by visual analogue scale) as well as laboratory findings was assessed. RESULTS: Wire-guided sphincterotomy was successful in all patients while uncomplicated pancreatitis occurred in one instance. In 16 patients (55%) there was macroscopic evidence of small stones (n = 2), sludge (n = 12) or both (n = 2) following bile duct exploration. In addition, microscopy showed bile crystals in all four patients who had no macroscopic findings. All four patients with elevation of pancreatic enzymes prior to treatment, and four of those eight patients with previous cholecystectomy, showed evidence of biliary pathology. The initial median pain intensity was 8 (range 1-10); 26 patients became pain-free within 3 months following endoscopic sphincterotomy. While 26 of 28 patients (93%) remained asymptomatic over a median follow-up period of 19 months (range 12-26), one died of an unrelated malignancy 6 months after therapy. CONCLUSIONS: Endoscopic sphincterotomy may be acceptable in patients with typical clinical presentation suggesting a papillary or biliary origin of pain without further diagnostic work-up. Contrary to expectations, diagnostic ERC was insensitive in detection of the biliary etiology of symptoms in this selected group of patients.

Detection of pancreatic metastases by EUS-guided fine-needle aspiration.

BACKGROUND: Metastases to the pancreas are usually found incidentally. Tissue diagnosis is imperative because imaging alone is incapable of differentiating them from primary pancreatic tumors. This study tested whether it is possible to differentiate metastases from other focal pancreatic lesions by using EUS-guided fine-needle aspiration (EUS-FNA) for cytodiagnosis. METHODS: One hundred fourteen consecutive patients (mean age 61 years) with focal pancreatic masses, detected on CT, underwent EUS-FNA by using a linear-array echoendoscope and 22-gauge needles. RESULTS: Adequate specimens were obtained from 112 lesions. Carcinomas were identified in 68 cases (60.7%), 56 (50%) of pancreatic origin and 12 (10.7%) from distant primary tumors. The metastases were all located in the head and body of the pancreas and measured 1.8 to 4.0 cm. The echo-texture was heterogeneous or hypoechoic in all cases and resembled that of primary tumors. Six of the 12 patients with metastatic disease had a prior diagnosis of cancer (breast, 3; renal cell, 2; salivary gland, 1), 4 of them with a recurrence and 2 with a second carcinoma metastasizing to the pancreas. Six patients without a prior diagnosis of cancer had metastases from renal cell, colonic, ovarian, and esophageal carcinomas; one metastasis was from an unknown primary and another was from a malignant lymphoma. These findings influenced the therapeutic strategy in 8 patients who underwent nonsurgical palliation. There were no complications. CONCLUSIONS: Pancreatic metastasis is an important cause of focal pancreatic lesions, but the EUS features are not diagnostic. Simultaneous EUS-FNA allows cytodiagnosis and can have a decisive influence on the selection of appropriate therapeutic strategies.

[Endoscopic argon plasma coagulation of Barrett mucosa]. / Endoskopische Argon-Beamer-Koagulation der Barrett-Mukosa.

BACKGROUND: Up to 10% of patients with Barrett's esophagus develop adenocarcinoma of the distal esophagus. Endoscopic surveillance is recommended. We studied the potential of Argon plasma coagulation (APC) for eradication of Barrett's esophagus. METHODS: Indication for APC was the histologic evidence of columnar epithelium with a length of > or = 2 cm, located proximal of the cardia and with the presence of goblet cells. Endoscopic therapy was performed using an Argonbeamer (Beamer 2, Erbe Company, Tübingen, Germany) under i.v. sedation and repeated in intervals of 2-3 weeks with the aim of complete eradication of Barrett's epithelium. One month after macroscopic Barrett eradication, superficial and deep biopsies were obtained every 2 cm in 4 quadrant technique to confirm the endoscopic aspect of complete eradication. RESULTS: We report our results (follow-up median: 12 mths., 3-25) in the first 12 patients (8m/4f, median age 57 yrs., 42-69) in which treatment was completed. In one case there was evidence of moderate dysplasia. A mean of 5 (4-11) sessions were required for complete Barrett eradication in 11 patients (median size of Barrett-segment: 4 cm, range 2-11), in one patient partial regression of 50% was observed treatment was discontinued after 17 sessions while only. Deep biopsies showed subepithelial columnar epithelium islands in one case, recurrence of Barrett occurred in 2 cases after 3 and 6 months. Under APC-treatment, 11/12 patients complained about retrosternal pain and odynophagia. No other complications were observed. CONCLUSION: Our preliminary results indicate that APC is safe and effective to eradicate Barrett's epithelium. Follow-up in a larger number of patients is necessary to assess longterm results (Barrett recurrence, decrease in the incidence of the adenocarcinoma), before APC may generally be recommended.

The role of endoscopic therapy in the treatment of bleeding varices.

The role of endoscopy in bleeding varices is both diagnostic and therapeutic. While sclerotherapy of oesophageal varices remains an established modality, ligation has, in view of its higher safety margin, turned out to be superior in recent years. The excellent initial results of ligation are, however, tainted by a higher recurrence rate in the long term. Since the end-point of treatment is the achievement and maintenance of variceal eradication, the addition of low-dose sclerotherapy following initial eradication by ligation seems to be the optimal method to combine the best of both techniques. In the management of life-threatening bleeding from oesophageal varices and gastric varices, cyanoacrylate remains the only promising non-surgical option. Primary endoscopic prophylaxis is still under evaluation. It is only justified in high-risk patients with large varices bearing red colour signs and in the presence of an intolerance of or contra-indication to propranolol. When indicated, ligation seems to be preferable, and the addition of low-dose sclerotherapy after initial variceal eradication may maintain the benefits accrued in such high-risk patients. The present review examines the available evidence regarding the above issues in the recent literature.

[Endosonographically controlled fine needle aspiration cytology--indications and results in routine diagnosis]. / Endosonographisch gesteuerte Feinnadelaspirationszytologie--Indikationen und Ergebnisse in der Routinediagnostik.

UNLABELLED: The usefulness and clinical utility of routine EUS-guided fine needle aspiration cytology (FNA) in the diagnosis of lesions adjacent to the upper gastrointestinal tract was prospectively studied. METHODS: EUS/FNA was performed in 122 patients for 125 lesions: Mediastinal lymph nodes (n = 56), pancreatic lesions (n = 45), paragastric masses (n = 12), submucosal tumors (n = 4) and small hepatic lesions (n = 2) were successfully punctured for cytological diagnosis. RESULTS: Adequate material was gained in 119 out of 125 punctures (95%). Overall sensitivity, specifity, positive and negative predictive value were 90%, 98%, 98% and 89%. Results of EUS/FNA in mediastinal lymph nodes were superior (95%, 100%, 100%, 90%) to those in pancreatic lesions (80%, 100%, 100%, 80%). In paragastric masses sensitivity was 100% whereas specifity was only 67%--due to one false-positive result. Out of four submucosal tumors diagnosis was revealed in three. Two liver metastasis were successfully punctured. 35 out of 56 mediastinal nodes showed malignancy. 27 metastases of lung-, three of gastric-, two of renal cancer and three Non-Hodgkins's lymphoma were diagnosed. The cytological results of 45 pancreatic lesions showed cancer in 19 and chronic inflammation in 21, two abscesses and three benign cysts. There were no complications. 37 patients were treated on outpatient's basis. CONCLUSIONS: EUS-guided FNA is an accurate and safe technique to sample cytology from lesions adjacent to the wall of the upper gastrointestinal tract. New indications may be established for the diagnosis of lung cancer or metastases of other spreading out into the mediastinum or the celiac axis.

Stent retriever for dilation of pancreatic and bile duct strictures. brand@uke.uni-hamburg.de.

BACKGROUND AND STUDY AIMS: Dilation of high grade strictures of pancreatic or biliary ducts using dilating or balloon catheters may fail. We evaluated the efficacy of the 7-Fr Soehendra Stent Retriever used as a dilator. PATIENTS AND METHODS: Following sphincterotomy, the stricture was first negotiated with a 260 cm long 0.032-inch J-type Terumo wire. Dilation was then attempted using a 7-Fr dilating catheter. If the stricture could not be traversed, the 7-Fr Stent Retriever was inserted over the Terumo wire to dilate the stricture. Between May 1996 and January 1997, the Stent Retriever was used for dilation in 32 patients with biliary or pancreatic duct strictures. RESULTS: The indication for therapeutic endoscopic retrograde cholangiopancreatography (ERCP) was symptomatic chronic pancreatitis in 21 patients (twelve men, nine women; mean age 45.7, range 26-70). The mean length (+/-SD) of the pancreatic duct strictures was 20mm+/-10 (range 3-55) with a prestenotic ductal diameter of 9mm+/-2 (range 2-15). Out of 21 patients, nine suffered from pancreaticolithiasis and were treated with extracorporeal shock wave lithotripsy. All but three patients underwent successful stenting in the same session. Another 11 patients (four men, seven women; mean age 67.4, range 47-85) had cholestasis because of benign or malignant bile duct strictures. The mean length of the strictures was 20mm+/-5 (range 3-40), and the mean prestenotic diameter was 10mm+/-5 (range 4-21). Stenting was easily done in all of these patients in the same session. Symptom relief was observed within the first week after stenting in all patients with a biliary or pancreatic stricture. In seven cases, material for cytological examination was obtained from the bile duct, which revealed malignancy in two cases. There was no complication associated with the use of the Stent Retriever. One subcapsular liver perforation was caused by the guide wire and occurred prior to the use of the Retriever. CONCLUSIONS: Tight pancreatic and bile duct strictures can be dilated successfully with the Stent Retriever. The procedure is of low risk. In addition, tissue sampling is possible in some cases.