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Table of Contents
Year : 2019  |  Volume : 11  |  Issue : 4  |  Page : 443-446  

Spontaneous knotting of urinary catheters placed with nonindwelling intent: Case series and literature review

Department of Urology, Apollo Hospital, Hyderabad, Telangana, India

Date of Submission03-Feb-2019
Date of Acceptance01-Aug-2019
Date of Web Publication9-Oct-2019

Correspondence Address:
Dr. Sanjay Sinha
Department of Urology, Apollo Hospital, Jubilee Hills, Hyderabad - 500 033, Telangana
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DOI: 10.4103/UA.UA_15_19

PMID: 31649470

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Urethral catheters are placed with nonindwelling intent chiefly for clean intermittent catheterization (CIC), imaging, or collection of a urine sample. Catheter knotting can be a troublesome complication, especially when it occurs in children often resulting in interventions under anesthesia in the operating room. Three children (4 years male, 4 years female, and 6 years male) presented with knotted feeding tubes placed for CIC. Details of these and an additional 31 patients are discussed in a short review. Knotting occurred almost exclusively in children (33/34, 97%), was more common in boys (22/34, 65%) and most often involved a feeding tube (27/34, 79%) with knotting in the bladder (28/34, 82%). Insertion length, caliber and stiffness of catheter, technique, and patient factors are important factors. Avoiding excessive insertion and use of an appropriate size of catheter (that is not too small) may reduce the risk. Manipulation alone (12/34, 35%), with guidewire (5/34, 15%), or with dilatation (3/34, 9%) is most often successful and is best accomplished under general anesthesia. Endourology (7/34, 21%), laparoscopy (1/34, 3%), or an incision (5/34, 15%) may be necessary in some patients. Safeguarding urethral integrity is the overarching concern.

Keywords: Catheter knotting, clean intermittent catheterization, feeding tube, non-indwelling urinary catheter

How to cite this article:
Singh VP, Sinha S. Spontaneous knotting of urinary catheters placed with nonindwelling intent: Case series and literature review. Urol Ann 2019;11:443-6

How to cite this URL:
Singh VP, Sinha S. Spontaneous knotting of urinary catheters placed with nonindwelling intent: Case series and literature review. Urol Ann [serial online] 2019 [cited 2020 Jul 14];11:443-6. Available from: http://www.urologyannals.com/text.asp?2019/11/4/443/266964

   Introduction Top

Urethral catheters are placed with nonindwelling intent chiefly for clean intermittent catheterization (CIC), imaging, or collection of a urine sample. Catheter knotting can be a troublesome complication, especially when it occurs in children often resulting in interventions under anesthesia in the operating room. Such failure is different from failure to remove indwelling catheters. We present three patients with this problem and review the literature to suggest recommendations.

   Case Report Top

All three patients were children (4 years female, 4 years male, and 6 years male), who presented with failure to remove a catheter placed for CIC as a part of neurogenic bladder management. In one boy, catheter knotting occurred in the urethra [Figure 1], while the cause was intravesical knotting in the other two [Figure 2] and [Figure 3]. Gentle manipulation under general anesthesia was successful in two of the patients, while one 6-year-old male needed division of the catheter with cystoscopic extraction.
Figure 1: Knotting of clean intermittent catheterization catheter in the bladder of a 4-year-old girl operated in infancy for lumbosacral meningomyelocele. The 7F feeding tube could not be removed in the outpatient department. However, on gentle manipulation under general anesthesia, the knot detangled, and the catheter could easily be removed

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Figure 2: Knotting of clean intermittent catheterization catheter in the urethra of a 6-year-old boy with neurogenic bladder due to lumbosacral meningomyelocele. The 6F feeding tube could not be removed under local anesthesia in the emergency room but could be removed after instilling copious amounts of lubrication under general anesthesia

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Figure 3: A 4-year-old boy with a history of neurogenic bladder secondary to anorectal malformation. The 6F feeding tube got knotted in the bladder and could not be removed despite attempts at detangling under general anesthesia in the operating room. The meatal end was divided, and the catheter was pushed back into the bladder. The knot could be unraveled at cystoscopy using a grasper and the catheter was removed uneventfully

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   Discussion Top

Failure of removal of a urethral catheter placed with nonindwelling intent is a sporadic problem that must be regarded as avoidable morbidity. It can be a frightening experience for children and their parents with potential implications for compliance with future CIC. A total of 29 publications representing 31 cases were identified using the PubMed search terms “catheter” and “knotting or entangl*” and secondary sources [Table 1].[1],[2],[3],[4],[5],[6],[7],[8],[9],[10],[11],[12],[13],[14],[15],[16],[17],[18],[19],[20],[21],[22],[23],[24],[25],[26],[27],[28],[29] We excluded patients in whom any type of catheter was placed with an indwelling intent. Failure to remove indwelling catheters are most often due to malfunction of the balloon.[30] Even when a nonself-retaining catheter is used, long dwell times and increased possibility of catheter migration that might permit knotting make these patients fundamentally different.
Table 1: Details of published case reports of knotting of catheters placed with nonindwelling intent including the current series of patients

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Previous reviews have often included patients, in whom catheters were placed with nonindwelling intent.[9],[16],[31]

Almost all the affected patients were children from newborn to 12 years of age (33/34, 97%), except a 75-year-old female who had knotting of a urodynamics catheter [Table 1]. Boys were more commonly affected (22/34, 65%). The location of knotting was the bladder (28/34, 82%) urethra (5/34, 15%), or catheterizable conduit (1/34, 3%). Catheter size involved was 4F (1), 5F (6), 6F (7), 7F (1), 8F (14), 10F (1), 12F (2), and unknown (2). The most common type of catheter involved was an infant feeding tube (27/34, 79%). Other catheters involved were ureteric catheter (1), latex Foley (1), red rubber (2), mentor CIC catheter through catheterizable stoma (1), double-lumen urodynamics catheter in the 75-year-old female (1), and unknown (1).

Catheter knotting is logically related to five factors, namely length of insertion, diameter of catheter, physical characteristics of the material, catheterization technique, and anatomical patient factors. The latter two might be critical in urethral knotting. Failure to recognize the subtle pushback from urethral coiling or the presence of a capacious posterior urethra can allow urethral knotting to occur.

Limiting the length of insertion of catheter depending on the age and gender of the patient is important in avoiding this problem.[3] The urethra is 2.2 cm at birth, 2.5 cm at 5 years, and reaches 3.8 cm in adult females, while it is 5 cm at birth, 8 cm by 3 years, and reaches 17 cm in adult males.[32] It has been recommended that the maximum length of catheter insertion should be 5 cm and 6 cm in newborn females and males and 2.5 cm and 5 cm in premature females and males, respectively.[9] However, this would imply that the intravesical length of catheter in the male infant would be just 1 cm making it prone to slippage into the urethra. We recommend inserting the catheter not more than an additional 4 cm beyond the estimated urethral length in children under 5 years and 5 cm for older children. This is a reasonable compromise between reducing the risk of knotting while avoiding catheter slippage. The catheter should be taped to prevent inadvertent advancement if required such as during imaging studies.[12] These requirements are likely to be different in patients who are being catheterized with indwelling intent, where the design of the balloon catheter (distance between tip of catheter and base of balloon) may necessitate a longer insertion length and technique.[32]

Feeding tubes are commonly used to catheterize the bladder in young children since they are cheap and widely available in multiple small sizes.[3] Use of purpose-specific urethral catheters rather than generic feeding tubes or similar catheters with a visible clear mark on the catheter based on the age and gender may help to reduce the risk.

Narrower caliber catheters are more likely to coil, and one needs to balance between the potential trauma of larger catheters and the risk of knotting with smaller ones. Use of 8F catheters for children above the age of 1 year and 10F above the age of 9 years is suggested.[9] These calibers also allow for a rapid emptying of the bladder ensuring better compliance with CIC principles. When available, use of dedicated CIC catheters may be preferable to feeding tubes, but the authors are not aware of any study that has specifically studied this issue.

All patients (and parents of small children) should be counseled regarding the inadvisability of using force and the importance of recognizing the subtle pushback from catheters that might be coiling in the urethra. In all such situations, the need to withdraw the tube, relubricate the urethra, and reinsertion must be discussed.

Catheter removal was accomplished by manipulation alone using gentle traction (12/34, 35%), manipulation with detangling using a guidewire (5/34, 15%), manipulation with dilatation (3/34, 9%), endourology techniques (7/34, 21%), by an incision in 5 (meatotomy 1, bulbar urethrotomy 1, cystostomy 2, and percutaneous suprapubic cystostomy with cystoscopy 1), and laparoscopy in one patient. Catheter manipulation under general anesthesia in the operating room with copious lubrication can succeed despite failure of a similar attempt in the outpatient room. The relaxation to both patient and surgeon afforded by the general anesthetic was a key to removal in two of our patients. Rarely, one may need to resort to endourology techniques or a surgical incision. The latter is more likely in male infants where the risk of long-term iatrogenic urethral stricture may outweigh any concerns regarding the morbidity of a small retrieval incision.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

   References Top

Harris VJ, Ramilo J. Guide wire manipulation of knot in a catheter used for cystourethrography. J Urol 1976;116:529.  Back to cited text no. 1
Gaisie G, Bender TM. Knotting of urethral catheter within bladder: An unusual complication in cystourethrography. Urol Radiol 1983;5:271-2.  Back to cited text no. 2
Sugar EC, Firlit CF. Knot in urethral catheter due to improper catheterization technique. Urology 1983;22:673-4.  Back to cited text no. 3
Klein EA, Wood DP, Kay R. Retained straight catheter: Complication of clean intermittent catheterization. J Urol 1986;135:780-1.  Back to cited text no. 4
Foster H, Ritchey M, Bloom D. Adventitious knots in urethral catheters: Report of 5 cases. J Urol 1992;148:1496-8.  Back to cited text no. 5
Parker AC. A rare complication of pediatric catheterization. Pediatr Nurs 1993;19:194-5.  Back to cited text no. 6
Ball RA, Horton CE Jr., Mandell JA. Transurethral removal of knotted bladder drainage catheter in a male following bladder neck reconstruction. Urology 1993;41:234-6.  Back to cited text no. 7
Konen O, Pomeranz A, Aronheim M, Rathaus V. A urethral catheter knot: A rare complication of cystourethrography. Pediatr Radiol 1996;26:757-8.  Back to cited text no. 8
Carlson D, Mowery BD. Standards to prevent complications of urinary catheterization in children: Should and should-knots. J Soc Pediatr Nurs 1997;2:37-41.  Back to cited text no. 9
Gonzálvez Piñera J, Fernández Córdoba M, Vidal Company A. Intravesical knot of foley catheter: Unusual complication of cystourethrography in children. An Esp Pediatr 2000;53:601-3.  Back to cited text no. 10
Steinbecker KM, Teague JL. Catheter knotting in a catheterizable urinary reservoir, J Pediatr Surg, 2001; 36:516-7.  Back to cited text no. 11
Arena B, McGillivray D, Dougherty G. Urethral catheter knotting: Be aware and minimize the risk. CJEM 2002;4:108-10.  Back to cited text no. 12
Dogra PN, Nabi G, Goel R. Endoscopic removal of knotted urethral catheter: A point of technique. Urol Int 2003;71:8-9.  Back to cited text no. 13
Turner TW. Intravesical catheter knotting: An uncommon complication of urinary catheterization. Pediatr Emerg Care 2004;20:115-7.  Back to cited text no. 14
Lodha A, Ly L, Brindle M, Daneman A, McNamara PJ. Intraurethral knot in a very-low-birth-weight infant: Radiological recognition, surgical management and prevention. Pediatr Radiol 2005;35:713-6.  Back to cited text no. 15
Pappano D, Bass E. Case in Point: Bladder Knots. Pediatrics Consultant Live; 2006. p. 5. Available from: http://www.pediatricsconsultantlive.com/articles/case-point-bladder-knots. [Last accessed on 2018 Dec 16].  Back to cited text no. 16
Ayyildiz A, Huri E, Nuhoǧlu B, Germiyanoǧlu C. Unexpected complication after cystometry in the hypocompliant urinary bladder: Formation of a knot in the double lumen urethral catheter – A case report. Int Urol Nephrol 2006;38:527-9.  Back to cited text no. 17
Sithasanan N, Kihne M, Naidu RR, Ramanujam TM. Twisted fate of bladder catheters. Med J Malaysia 2006;61:369-70.  Back to cited text no. 18
Sambrook AJ, Todd A. Untangling of knotted urethral catheters. Pediatr Radiol 2007;37:380-3.  Back to cited text no. 19
Kilbane BJ. Images in emergency medicine. Knotting of a urinary catheter. Ann Emerg Med 2009;53:e3-4.  Back to cited text no. 20
Bagheri MH, Nabavizadeh SA, Shirazi M, Farahmand M, As'adi K, Mansouri S. Foley catheter entrapment resulting from the formation of a true knot in a female infant: Sonographic findings. J Clin Ultrasound 2009;37:360-2.  Back to cited text no. 21
Khullar S, Bera MK, Kundu AK, Pal DK. Successful management of auto knotted intravesical infant feeding tube by minimal invasive technique. J Indian Assoc Pediatr Surg 2012;17:174-5.  Back to cited text no. 22
[PUBMED]  [Full text]  
Ozkan A, Okur M, Kaya M, Büyükkaya R, Katranci AO, Kucuk A. An easy technique for removal of knotted catheter in the bladder: Percutaneous suprapubic cystoscopic intervention. Int J Clin Exp Med 2013;6:603-5.  Back to cited text no. 23
Jehangir S, David DD. Knotted urethral catheter: A twist in the tail. BMJ Case Rep 2017;2017. pii: bcr-2016-217834.  Back to cited text no. 24
Terentiev V, Khentsinsky O, Dickman E, Cortis C, Arroyo A. A knotted urethral catheter in the emergency department. Pediatr Emerg Care 2017;33:190-1.  Back to cited text no. 25
Perera TM, Gamhewage NC, Aaqiff UM. A case of intravesical knotting of a feeding tube used as a urethral catheter. Sri Lanka J Child Health 2017;46:80-1.  Back to cited text no. 26
Minami Y, Tanaka H, Masumoto K. Knotting of a urethral catheter. Pediatr Int 2017;59:932-3.  Back to cited text no. 27
Kervancioglu E. A rare case presentation: Intravesical catheter knotting. J Endourol Case Rep 2018;4:82-3.  Back to cited text no. 28
Erikci VS, Mert M, Özdemir T, Köylüoğlu G. Management of bladder catheter knot in a girl: A case report and review of literature. J Emerg Med Care 2018;1:102.  Back to cited text no. 29
Hollingsworth M, Quiroz F, Guralnick ML. The management of retained foley catheters. Can J Urol 2004;11:2163-6.  Back to cited text no. 30
Pearson-Shaver AL, Anderson MH. Urethral catheter knots. Pediatrics 1990;85:852-4.  Back to cited text no. 31
Smith AB, Adams LL. Insertion of indwelling urethral catheters in infants and children: A survey of current nursing practice. Pediatr Nurs 1998;24:229-34.  Back to cited text no. 32


  [Figure 1], [Figure 2], [Figure 3]

  [Table 1]


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