Annals of African Medicine

: 2013  |  Volume : 12  |  Issue : 1  |  Page : 40--42

Spontaneous knotting of a feeding tube in the bladder

Ndubuisi Eke1, Beleudanyo G Fente2, Richard C Echem1,  
1 Department of Surgery, Urology Unit, University of Port Harcourt Teaching Hospital, Port Harcourt, Nigeria
2 Department of Surgery, Niger Delta University, Amassoma, Bayelsa State, Nigeria

Correspondence Address:
Ndubuisi Eke
Department of Surgery, PO Box 5575, Port Harcourt


Urinary catheterization is often performed in the pediatric age group. The procedure although safe, is not free of complications. Knotting of the urinary catheter is a rare but serious complication. A seven-year-old boy presented with left-sided neuroblastoma and underwent an exploratory laparotomy during which it was found that he had an inoperable tumor. There was a nodule obstructing the left ureter. This was resected and an end-to-end anastomosis of the ureter was carried out. A size 8 French (Fr) feeding tube was introduced through the urethra to monitor the patient«SQ»s urine output and fluid balance in the absence of a self-retaining pediatric catheter. An attempt at removal 48 h later was unsuccessful. The patient was afterwards, on the sixth postoperative day, anaesthetized and the tube was pulled out. It was noticed that the catheter was knotted. The case is reported with a limited discussion of relevant literature. Spontaneous knotting of a catheter is a rare complication. With availability of appropriate catheters and adequate knowledge and skill, this complication can be reduced to the barest minimum.

How to cite this article:
Eke N, Fente BG, Echem RC. Spontaneous knotting of a feeding tube in the bladder.Ann Afr Med 2013;12:40-42

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Eke N, Fente BG, Echem RC. Spontaneous knotting of a feeding tube in the bladder. Ann Afr Med [serial online] 2013 [cited 2021 Jun 22 ];12:40-42
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Urinary catheterization is a common urologic practice which has been utilized for decades. [1] Although Foley's catheter is preferred, feeding tubes are suitable alternatives which have been utilized in infants and children. [1],[2],[3] Urinary catheterization is generally a safe procedure but it is not free of complications. One such complication is knotting of the urinary catheter. [1],[2],[4] The aim of this paper is to report spontaneous knotting of a feeding tube utilized in the urinary catheterization of a child.

 Case Report

A seven-year old boy presented at the urology unit of the University of Port Harcourt Teaching Hospital with a four-month history of increasing abdominal swelling and weight loss. Examination revealed a cachectic and pale child with a knobby upper abdominal mass extending across the midline. An intravenous urogram (IVU) showed a left hydronephrosis and a normal right kidney. A presumptive diagnosis of neuroblastoma was made.

At operation an inoperable tumor extending from the left suprarenal gland to the hilum of the liver and invading the colonic mesentery was noted. A solitary nodule was noted to obstruct the left ureter. This was resected and the continuity of the left ureter was re-established by an end-to-end anastomosis using chromic catgut suture. The tumor was biopsied. A size 8 French (Fr) feeding tube was introduced into the bladder by the surgeon through the urethra to monitor the patient's urine output and fluid balance as a self-retaining pediatric catheter was unavailable. The tube was strapped securely on the patient.

Postoperatively the patient bled profusely from the wound. This required exploration of the wound. A few oozing points were observed from the skin. The wound was re-sutured with continuous Nylon. The bleeding was adequately controlled by this measure. He recovered unremarkably and the wound healed without sepsis. An attempt to remove the feeding tube catheter 48 h after its introduction was unsuccessful. The child was anaesthetized on the sixth postoperative day and the tube was pulled out. It was noticed that there was spontaneous looping and knotting of the catheter [Figure 1]. Subsequently, the patient voided urine satisfactorily and was discharged home after ten days in hospital. He did not return for follow-up.{Figure 1}


Urinary catheterization is utilized in the pediatric age group for both diagnostic and therapeutic purposes. It is used in diagnostic radiological procedures like cystourethrography. [1],[2],[4] For therapeutic purposes, it can be used to monitor urine output and to relieve urinary retention.

Ideally, the Foley's catheter should be used in the catheterization of children. [1],[2] However, the infant feeding tube is still a suitable alternative, especially in the developing countries where pediatric size Foley's catheters may not be readily available. [3] Some authors have questioned their appropriateness as urinary catheters. [5] While urethral trauma and infection are known complications, spontaneous knotting is a rare complication which has recently been recognized. [1],[2],[4]

Spontaneous knotting of the urinary catheter, as reported above, has been reported to occur in 0.2 per 100,000 catheterizations. [1] Knotting probably occurs as a result of insertion of an excessive length of small-caliber catheter into the bladder. The excessive length forms a loop and coils on itself. As the bladder decompresses, the catheter tip loops through the coil thereby creating a knot. [2],[6] When the catheter is pulled out, the coil tightens and if a knot is not yet formed, a knot an then occur. As shown in [Figure 1], excessive length was inserted into the bladder giving room to the looping and knotting which occurred.

Recognition of the complication of catheter knotting is important. This hazard needs to be borne in mind when inserting the catheter as well as when difficulty is encountered while attempting to remove the catheter. Although knotting can be recognized radiologically, [5] a high index of suspicion is required where difficulty in removal of the catheter is noticed.

Various methods have been employed in the removal of a knotted catheter. The methods include gentle but sustained traction under general anesthesia, [7] open cystostomy [6] and endoscopic retrieval methods. [8] The most commonly utilized method is gentle but sustained traction under general anesthesia but it could be complicated by urethral trauma [1] and subsequently, urethral stricture. An open cystostomy can also be used to retrieve a tube knotted in the bladder. In the index case, it was felt that open cystostomy would be more traumatic than a gentle pull on the catheter. The child presented above was not observed long enough to exclude a stricture following the urethral injury because he did not return for follow-up.

Prevention of spontaneous knotting of the feeding tube can be achieved by careful selection of the 'catheter' and gaining better understanding of urethral anatomy and safe insertion lengths. [1] The newborn male urethra measures 5 cm, increasing to 8 cm by three years of age and to 17 cm by adulthood. [1] The female urethra length is comparatively shorter and grows at a slower rate. It measures 2.18 cm at birth and increases to 2.54 cm by five years of age and to 3.78 cm in adulthood. [1]

Another measure to prevent knotting is to pass the tube gently. The process should be terminated as soon as the catheter enters the bladder. This will be indicated by flow of urine into the tube. The catheter should be strapped securely, especially if an infant feeding tube is being utilized. With a short length of the tube inside the bladder, it is unlikely for it to loop and knot spontaneously. Also, if inadvertent advancement of the catheter is prevented, it is unlikely that excessive length of the catheter can advance into the bladder. Securing the inserted catheter is helpful to prevent inadvertent advancement of the catheter into the bladder. [1] This is particularly important when infant feeding tubes are utilized.

Some other recommendations have been made to prevent catheter knotting. [2] These include the use of appropriate-length urinary catheters and/or insertion of appropriate lengths of catheterizing devices based on sex, age and purpose. The insertion lengths of 6 cm in a male newborn and 5 cm in a female newborn have been recommended. In low-birth weight babies, the use of size 4 Fr catheters (like umbilical artery catheters) is recommended. In extremely premature babies with birth weight of less than 750 g, the insertion length of <2.5 cm in girls or <5 cm in boys has been recommended. [2]

There is a need for sensitization of the staff involved in the catheterization of patients about this rare but serious complication. Some workers have advocated that all staff involved in the insertion, maintenance or removal of catheters should be suitably trained to minimize the risk of knotting and related complications. [5]


Although a rare complication, urinary catheter knotting should be borne in mind by all staff involved in the insertion, maintenance or removal of catheters. With the availability of appropriate catheters and adequate knowledge and skill, the complication of knotting can be reduced to a minimum.


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