Abstract
Knotting of feeding tubes or urinary catheters has been reported as a rare complication in paediatrics when draining the bladder. This is caused by inserting thin flexible tubes too far in, allowing it to coil. We present a case of a 70-year-old woman who was catheterised during a routine spinal surgery, and the catheter coiled and balloon failed to deflate requiring a cystostopic approach to puncture the balloon and remove it. Awareness of this complication in female catheterisation and education on length of catheter insertion is important to avoid this.
Keywords: urology, catheterisation / catheter care, urological surgery
Background
Spontaneous catheter knotting is an extremely rare complication, especially in adults.
Case presentation
A 70-year-old woman was admitted for an elective decompression and stabilisation surgery of her lumbar spine (L2/L3). She was catheterised at the time of her operation with a 12Fr long urethral catheter, and the procedure was uneventful. The patient was recovering well on the ward and started mobilising. On day 2 postoperatively, her catheter was planned for removal. Despite multiple attempts by several experienced nurses and doctors, the catheter balloon failed to deflate, and the valve did not allow further inflation. Other methods of cutting the valve or passing a wire via the balloon channel were attempted, and the catheter could not be removed. However, the catheter continued to drain.
An abdominal CT was scheduled to investigate this and rule out any bladder pathology; this revealed that the catheter was knotted inside the bladder (see figures 1 and 2). She underwent a rigid cystoscopy under general anaesthetic. This confirmed a knotted catheter just under the balloon preventing the balloon from deflating (see figure 3). The balloon was punctured using a Wilson’s needle, and the catheter was removed.
Figure 1.
Scout CT image showing a knot in the catheter.
Figure 2.
Sagittal CT views of the bladder showing a urethral catheter with a knot just above the bladder neck.
Figure 3.
Rigid cystoscopy showed catheter balloon failure to deflate due to a knot in the catheter.
Outcome and follow-up
The patient completed her postoperative rehabilitation and was discharged home.
Discussion
Spontaneous catheter knotting is a rare complication. There have been reports of knotted catheters in paediatric literature. It has been attributed to factors such as flexibility, length and diameter of the catheter. Its probable mechanism being the catheter coils into itself within the bladder, and the traction of removal causes a knot to form.1 2 Typically, catheters that are smaller in diameter and longer may contribute to increased risk of knotting.3
However, there is very limited evidence highlighting knotted catheters in adults. One case was reported in a 26-year-old man with an augmented bladder who regularly performs clean intermittent self-catheterisation for many years and presented once with a knotted catheter that was removed by gentle traction. It was suggested that the catheter knotted due to a combination of inserting the catheter fully and the patient’s underlying bladder pathology.4
In the case we present, a catheter knotted in a female patient with no underlying urethral or bladder pathology. Although the catheter was draining, the knot affected the balloon mechanism preventing it from deflating.
Nowadays, catheters tend to be universal in length with the shorter female catheters now phased out. This is on safety grounds to avoid accidentally using short catheters in male patients. When a long catheter is inserted in a male patient, it is recommended that the catheter is inserted fully and the balloon not to be inflated unless urine is seen draining to confirm position. In this case, it is likely that the catheter has been inserted fully and curled in the bladder. After the balloon was inflated and catheter pulled down, a knot developed and thus prevented the balloon from deflating.
In females and when using long urethral catheters, there is no need to insert the catheter fully as the female urethra averages 4 cm.5
This rare complication has a common theme with the published case reports: thin and long catheters that are inserted to the length that allow it to coil in the bladder.
Learning points.
Spontaneous urethral catheter knotting is a rare complication but can happen in adults.
Consider catheter coiling and subsequent knotting when experiencing difficult catheter removals.
There is no need to insert the catheter fully as the female urethra averages 4 cm.
Footnotes
Contributors: All authors have contributed to this work. SJ and JB planned and designed the initial draft. SJ and AS acquired and edited the images to comply with BMJ requirements. All authors (SJ, AS and JB) contributed to writing and editing the manuscript and discussion.
Competing interests: None declared.
Patient consent: Obtained.
Provenance and peer review: Not commissioned; externally peer reviewed.
References
- 1.Jehangir S, David DD. Knotted urethral catheter: a twist in the tail. BMJ Case Rep 2017;2017:bcr-2016-217834 10.1136/bcr-2016-217834 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 2.Ozkan A, Okur M, Kaya M, et al. An easy technique for removal of knotted catheter in the bladder: percutaneous suprapubic cystoscopic intervention. Int J Clin Exp Med 2013;6:603–5. [PMC free article] [PubMed] [Google Scholar]
- 3.Raveenthiran V. Spontaneous knotting of urinary catheters: clinical and experimental observations. Urol Int 2006;77:317–21. 10.1159/000096335 [DOI] [PubMed] [Google Scholar]
- 4.Brown SC, Lynn NN. An unusual (knotty) complication of clean intermittent self-catheterization in a patient with an augmented bladder. BJU Int 1999;84:539 10.1046/j.1464-410x.1999.00242.x [DOI] [PubMed] [Google Scholar]
- 5.Brooks JD. Anatomy of the lower urinary tract : Wein AJ, Kavoussi LR, Novick AC, Campbell-walsh urology. 9th edn Philadelphia: Saunders Elsevier, 2007:38–77. [Google Scholar]