Dislodgement of Radial EBUS-Guide Sheath Radiopaque Cuff: A Rare Complication

To the Editor: Radial probe endobronchial ultrasound (RP-EBUS) is recommended as an adjunct modality for the diagnosis of peripheral pulmonary lesions based on its favorable safety profile and its reasonable diagnostic yield.1 In a retrospective study of 965 consecutive procedures,2 a complication rate of 1.3% (0.8% pneumothorax, 0.5% infection) was reported, with no guide sheath breakage. Guide sheath dysfunction was not observed in a multicenter prospective registry3 nor in a meta-analysis of RP-EBUS studies.4 We herein report 2 cases of guide sheath breakage, review 2 additional cases, and offer possible explanations. A 65-year-old woman underwent RP-EBUS (using the UM-S20-20R-3 probe and the K-203 kit from Olympus Canada Inc.) for a 5.2 cm subpleural mass in the posterior segment of the right lower lobe. The lesion was localized using RP-EBUS, with a central probe position. Five transbronchial needle aspiration (TBNA) passes, 6 transbronchial biopsies (TBBx), 1 brushing, and 1 bronchoalveolar lavge were performed in that order. After TBNA, the guide sheath was noted to be displaced and tore at its tip. Sampling proceeded after replacing the guide sheath, but the radiopaque cuff remained in the airways. It was removed using forceps under fluoroscopy. The procedure was prolonged by several minutes, without adverse consequences. A 75-year-old man with a history of granulomatosis with polyangiitis underwent RP-EBUS for a centrally located 2.7 cm branching opacity in the posterior segment of the right upper lobe. The lesion was localized with a central probe position. Five TBNA passes, 1 brushing, and 3 TBBx were performed. When the biopsy forceps were introduced for the fourth biopsy, resistance was encountered and the forceps were withdrawn. It was then noted that the radiopaque cuff was dislodged. Forceps were used to retrieve the cuff under fluoroscopy. The retrieval added several minutes to the procedure, with no adverse consequences. When the guide sheath was removed, it was compressed and torn at the end. The compression of the guide sheath is thought to have been caused by the acute angle of the airway, compounded by the patient’s excessive cough. Over 200 RP-EBUS procedures have been performed at our institution since 2009. Although deformation and flattening of the Olympus guide sheath is frequently observed upon its removal from the bronchoscope, dislodgement of the distal radiopaque cuff was only seen twice. This complication has never been formally described in the literature, although 2 Food and Drug Administration Manufacturer And User facility Device Experience (MAUDE) reports describe such an occurrence.5 Potential causes of breakage of the guide sheath are numerous. A product defect could be responsible, but the manufacturer’s examination in the 2 MAUDE reports failed to reveal such an anomaly. Our 2 cases were separated by almost 1 year, excluding a lot manufacturing issue. However, the characteristics of the guide sheath are such that it can buckle at acute angles, collapse, and even shrink during sampling. The buckling can be a factor leading to perforation of the guide sheath. With repeated instrument insertion and removal, the cuff can then break off. This phenomenon is thought to be more likely when the target is reached through tortuous airways at sharp angles. But misuse of sampling tools may also explain sheath dysfunction. In one of the MAUDE report, the manufacturer concluded that the operator attempted to remove the biopsy forceps from the guide sheath while the cups were open. In the other report, repeated extension and withdrawal of a steerable curette from the guide sheath was thought to be the culprit factor. Furthermore, deployment of a TBNA needle proximal to the radiopaque cuff could lacerate the guide sheath and cause cuff dislodgement, especially if there is an acute angle in the sheath or if it is buckled. Even if deployed appropriately, the back-and-fourth motion required for TBNA sampling may damage the sheath, espcially if it is bent. These mechanisms probably played a role in the first case we described. The same could happen if the brush or forceps are deployed or opened inside the guide sheath. Although a rare event, the radiopaque cuff of the RP-EBUS guide sheath can get dislodged. In both cases reported here, the radiopaque cuff was retrieved. However, its retention could lead to a foreign body reaction, airway obstruction, and infection. Careful instrument manipulation, use of fluoroscopy with magnification for visualization of sampling tools’ functioning, and modification of the sheath might prevent this complication. Careful instrument manipulation, use of fluoroscopy with magnification for visualization of sampling tools' functioning, and modification of the sheath might prevent this complication. A more resistant sheath with preserved low friction and manoeuvrability is desirable, and making the sheath inherently radiopaque would obviate the need for a distal cuff. Stéphane Beaudoin, MD Linda M. Ofiara, MD Marc Bellerose, RRT Anne V. Gonzalez, MD, MScDivision of Respiratory Medicine, McGill University Health Centre, Montréal, QC, Canada

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