Acute Urinary Retention from Knotted Urethral Catheter Treated with Holmium Laser Ablation

Abstract

Background: Straight catheters are usually used for clean intermittent catheterization (CIC). Patients perform CIC without much difficulty. Spontaneous knotting of catheter is rare in large bore straight catheters and female patients.

Case Presentation: A 50-year old lady, case of neurogenic bladder on CIC inserted a 14F straight catheter, drained some urine but was unable to remove the catheter. She presented in emergency with retention of urine. Her X-ray and ultrasound examination revealed a knotted catheter. Conservative measures to remove the catheter such as forceful injection of radio-opaque contrast and passage of hydrophilic guidewire did not work. She was taken in the operating room. The knot was ablated using holmium laser through transurethral passage of an 8F ureteroscope.

Conclusions: Spontaneous knotting of urethral catheter is rare in adults. It should be suspected whenever a straight catheter cannot be removed. Inserting excessive length of catheter is an important risk factor. Holmium laser is an excellent tool to cut the catheter in a least invasive way when conservative measures have failed.

Introduction and Background

Clean intermittent catheterization (CIC) is an established modality of management in neurogenic bladder. Straight catheters are usually used for this purpose. Patients usually perform CIC without much difficulty. Spontaneous knotting of urethral catheter is an extremely rare complication considering several million catheters being used worldwide. It is seen in neonates and infants wherein thin feeding tubes are used for catheterization. Although rare, catheter knotting can involve significant morbidity. There are various options to manage a knotted urethral catheter. Sustained traction, using guidewire to unravel the knot, endoscopic retrieval, and open surgical removal have been described in the literature.¹

We are reporting a case of adult female patient with knotted straight urethral catheter ablated using holmium laser. The use of laser to cut a knotted catheter is being reported for the first time.

Clinical History

A 50-year old lady, case of neurogenic bladder on CIC had inserted a 14F straight R-90 PVC catheter (polyvinyl chloride catheter, GS-1012; Romsons Scientific and Surgical Industries, India) and drained some urine. It was a used and cleaned catheter. She used to clean the catheter by immersing in boiled water and then washing it in povidone iodine solution. She used to do CIC four times a day. Each catheter was being used for 2 weeks and then discarded. As the flow of urine was not satisfactory, she pushed in the catheter still further. But the flow did not improve. As not much urine was coming out, she pulled the catheter out. But on trying to withdraw the catheter, she felt resistance. She pulled the catheter, but the catheter could not be removed. She presented in emergency with retention of urine.

Physical Examination and Investigations

On examination she had mild fever (37.2°C). Bladder was palpable for three fingerbreadths above the pubic symphysis. There was suprapubic tenderness. A 14F catheter was hanging from the urethra. It was not draining any urine. There was some pericatheteric urine leak soiling her undergarments. Her perianal sensations were impaired. Her hemoglobin was 10.42 gm/dL. Total leukocyte count was 11,800/mm³. Serum creatinine was 1.9 mg/dL. Her abdominal X-ray showed knotted catheter. Ultrasound examination showed double loop of the catheter (Fig. 1).

FIG. 1.

(A) Abdominal X-ray showing catheter with knot (arrow), (B) ultrasonography showing two loops of the catheter; two arrows showing the loops of catheter, (C) contrast study delineating the catheter and knot.

Diagnosis

With these findings we made a diagnosis of knotted impacted urethral catheter.

Intervention

Attempt was made to untie the knot with forceful injection of radio-opaque contrast, but it did not help. Passage of hydrophilic stiff guidewire to undo the knot did not help. She was taken to the operating room. Dexmedetomidine and butorphanol were given intravenously. Lignocaine jelly was instilled in the urethra by the side of the catheter. An 7/8F ureteroscope (Karl Storz 27001L) was passed through the urethra by the side of the catheter. The knot was observed. A 600 μm laser fiber was passed. Energy setting of 1 J and 20 Hz was used. The knot was ablated using holmium laser (Karl Storz Calculase III, UL300-1), and pieces of the catheter were removed using a grasper (Fig. 2).

FIG. 2.

(A) Knot seen through ureteroscope, (B) knot being ablated, (C) pieces grasped, (D) catheter removed.

Follow-Up and Outcome

On follow-up, she is doing well with regular CIC and a stable creatinine of 2 mg/dL.

Discussion and Literature Review

Spontaneous knotting of urethral catheter is rare, possible incidence being 0.2 per 100,000 catheterizations.² Spontaneous knotting has been reported with long-term as well as short-term catheterizations. Examples of short-term catheterizations wherein spontaneous knotting has been reported are in and out catheterization for sample collection, CIC, and voiding cystouretrography. Spontaneous knotting has been reported with straight catheters and Foley balloon catheters as well.³ Knotting of two catheters such as suprapubic catheter and urethral catheter has also been reported.² Similarly knotting of urethral catheter and a Double-J stent is also reported in the literature. Spontaneous knotting is most often reported in neonates and children especially when a small caliber feeding tube is inserted for collection of urine sample. Knotting is rare in adults. Knotting is more common in male children because of overestimation of urethral length, thereby passage of excessive length of the catheter.² The commonest presentation is inability to remove the catheter. It is often possible to slide in the catheter but difficult to remove it. If a catheter is knotted in a urethra sliding in and pulling out, both would be difficult. Sometimes patients may present with retention of urine or pericatheteric leak of urine.² The likely mechanism for spontaneous knotting is excessive coiling of the catheter in the bladder. The end of the catheter abuts the bladder wall and then passes through the loop resulting in the knot.² Raveenthiran has reported an experimental study to evaluate the risk factors for catheter knotting. The predisposing factors for spontaneous knotting are elasticity, thickness and length of catheter inserted, catheters <10F and insertion >10 cm and overdistended bladder.¹

The knotting can be prevented by judicious passage of the catheter in bladder only as far as necessary. Feeding tubes are commonly used because of ease of use and low cost.⁴ If possible, flexible feeding tubes should be avoided. Female urethra is short. It is not necessary to insert the catheter fully.³ Our patient probably was not instructed to avoid putting in the catheter >4–5 cm. Spontaneous knotting of straight catheters is rare. Moreover knotting is rare in female patients. Although it was a reused catheter, that per se does not seem to be a risk factor in our case. When PVC catheters are repeatedly used, they usually become stiff. Stiff catheters would be less prone to knotting. As flexibility of the catheter is a predisposing factor for knotting, a stiff catheter is less likely to knot. In our case, it seems excessive length of catheter that was inserted into the bladder is the risk factor for knotting. Although knotting of urethral catheter is rare, removal may not be a simple matter. Associated morbidities are general anesthesia, radiation exposure, hematuria, and risk of urethral stricture.⁴ Various maneuvers such as gentle traction, urethral meatotomy, urethral dilation and manual traction, rigid cystoscopy and deflation of the balloon, removal with the help of ureteral catheter stylet, perineal urethrostomy, suprapubic percutaneous cystoscopy, and open suprapubic cystotomy have been reported. Interestingly, dilation of patent urachus for retrieval of knotted catheter is also reported in the literature.² Guidewire manipulation traction would work only if the knot is in “open loop” stage. This would involve radiation exposure. Gentle traction is likely to succeed in girls with knotted small caliber catheter because of short and pliable urethra.² But it can be traumatic to urethra at times and would not be useful if the knot is bulky.¹ In pediatric patients, one may have to resort to open surgical retrieval of the knotted catheter,¹ but in adults we can pass a thin ureteroscope by the side of the urethral catheter without much trouble. We report use of holmium laser through a thin ureteroscope. Holmium laser has excellent cutting properties and as the fiber is quite thin, it can be introduced through a ureteroscope channel. Use of laser for this indication has not been reported so far.

Conclusion

Spontaneous knotting of urethral catheter is rare but can occur in adults too. It can happen with straight and balloon catheters too. Inserting excessive length of catheter should be avoided to avoid knotting. Holmium laser is an excellent tool to cut the catheter in a least invasive way when conservative measures have failed.

Abbreviations Used

CIC

clean intermittent catheterization

PVC

polyvinyl chloride

Disclosure Statement

No competing financial interests exist.

Funding Information

No funding was received for this article.

Cite this article as: Mulawkar PM (2020) Acute urinary retention from knotted urethral catheter treated with holmium laser ablation, Journal of Endourology Case Reports 6:4, 428–430, DOI: 10.1089/cren.2020.0157.