Failure of Foley catheters

However, crosslinked silicone rubber is used so widely in catheters that other problems are more common than one might expeet. For example, Foley catheters are used for urinary drainage in patients and, if the tube breaks, serious problems can follow for the patient (Fig. 9.32). The catheter is more 

Catheters must withstand often substantial stresses, from the weight of urine when the collection bag is full, as well as from movement of the user, and these stresses induce fatigue. The catheter can break near the tip, in which case the end must be extracted surgically. Just this happened to a patient, Miss C, in 2007, and she experienced great discomfort and pain, not to mention distress without the device before a new catheter was implanted. The failed parts were returned, and she gave them to her pharmacist for examination, but they were discarded or lost, and so the cause of failure was never determined. However, the replacement catheter she was sent showed failure of almost exactly the same kind, and she sued the manufacturer as a result. The presence of a clean radial fracture (Fig. 9.33) without any applied stress implied a manufacturing defect in the material, vulcanized silicone rubber. 

34 Brittle fracture in ESEM showing the origin (arrow). 

35 Cusp in opposite fracture surface showing meeting of cracks (arrow). 

36 Voids revealed by crack growth in fracture surface (arrows). 

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