Find best premium and Free Joomla templates at

Care on double diaper technique after hypospadias repair

Bertozzi M., Prestipino M., Nardi N., Appignani A.
S.C. di Clinica Chirurgica Pediatrica - Università degli Studi di Perugia
Ospedale S. Maria della Misericordia, S. Andrea delle Fratte, Italy



Mirko Bertozzi MD
S.C. di Clinica Chirurgica Pediatrica
Università degli Studi di Perugia, Ospedale S. Maria della Misericordia
Loc. S. Andrea delle Fratte, 06100 Perugia - Italy
Tel : +39-075-5783376 / +39-339-3196807 / Fax : +39-075-5783376
E-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.



Temporary urinary diversion is routinely employed after hypospadias repair in children. A traditional closed urinary drainage system or an open drainage system into doubled diapers may be used. This last technique is well known for one day surgery repair of anterior hypospadias. Modern disposable infant diapers have absorbent gelling material (cross-linked sodium polyacrylates) able to tightly hold water as much as helping to segregate urine apart from stools. We report the first two cases of unexpected catheter blockage in babies submitted to hypospadias repair with a transurethral vesical catheter draining the urine between 2 diapers due to cross-linked sodium polyacrylates.

key words: double diaper technique, catheter blockage, super absorbent polymers, hypospadias



Temporary urinary diversion is routinely employed after hypospadias repair in children. Open urinary drainage using the double diaper technique is a method very often used of short-term catheter management after pediatric urethral surgery [1].

Nowadays the disposable diaper is composed of an inner layer of polyester that allows liquids to pass through to a layer of absorbent material, cross-linked sodium polyacrylates also called superabsorbent polymers (SAP) and an outer waterproof plastic layer of polyethylene film. SAP absorb and retain, under a slight mechanical pressure, about 30 times their weight in urine [2]. The swollen gel holds the liquid in a solid, rubbery state and prevents the liquid from leaking onto the baby’s skin and clothing.

Cases report

Two babies 18 months and 34 months-old respectively affected by anterior hypospadias underwent in our Unit a day-surgery repair using tubularized incised plate urethroplasty protected with double-cross flap protection [3-4]. How we usually do, the urethroplasty was prepared using a Foley catheter (6Ch for the first patient and 8Ch for the second one) and once the intervention was completed a dressing was applied with open urinary drainage using the double diaper technique. In the first postoperative day the two patients had an acute urinary retention due to catheter blockage. Analyzing the catheters, we realize that there was a granular substance ( fig. 1) into the lumen of the catheters that arose from the created hole we made on the first of the double diaper.

13 JPSS 8 1 2010-13

Figure 1: SAP found in the catheters’ lumen 

All the attempts carried out to free the catheter from the blockage was unsuccessful, reason why we then decided to replace the catheters, being afraid of the possible complications related to this manoeuvre in the first postoperative day after urethroplasty.

Once the catheters were replaced, a complete migration of the granulated substance until the tips of the removed catheters was seen. This substance creates a complete blockage of the catheters and the loss of urine drainage.

Fortunately the extreme manoeuvre of catheters’ substitution did not create complications in the performed urethroplasties and at 1 year follow up we did not see fistulae or stenosis.


Temporary urinary diversion is routinely employed after hypospadias repair in children. It has been seen that even for distal hypospadias repairs, urinary diversion gave better results than for repairs without diversion [5]. There are many methods for urine drainage and some of them require prolonged hospital stay with increased cost and discomfort to the child. Open urinary drainage using the double dia- per technique is a safe and effective method of short-term catheter management after pediatric urethral surgery [6]. In this technique, the distal end of the catheter is taken out through the inner diaper, creating a hole, and the urine is allowed to drip into the outer diaper. The mothers are advised to replace the outer diaper every 4-6 h, once it gets completely wet with urine. The inner diaper is changed when the child passes stools. The penis with the dressing and the catheter are entirely within the diapers and thus are concealed from the child′s view.

Modern baby diapers contain polyacrylic acid, a SAP. Polyacrylic acid is a polymer made from the monomer acrylic acid. These long chains contain thousands of monomer units, and the polymer also has some cross-linking between the chains.

Polyacrylic acid is very hydrophilic because of the carboxylic acid groups (COOH) in the polymer and it can hydrogen-bond to water molecules. When this polymer was added to a beaker with water and stirred, it absorbed many times its weight in water.

A disposable diaper is made in layers. The top layer is permeable so the fluid can quickly pass through. It is a material that does not absorb, so it stays dry next to the skin. The middle layer is made of fluff material to catch the fluid, with SAP either layered in or blended in with the fluff. This causes the liquid to gel into a more solid state and prevents it from leaking onto skin and clothing. Of course, the outer layer is non-permeable to hold the moisture in and away from clothing. The most commonly available SAP are hard, dry, granular powders that look much like clean white sand or granular table sugar. When these polymer particles are placed in water, slurry of water and the particles is formed. Gradually the SAP absorbs the water, turning into a soft, rubbery gel [2].

In our Unit we adopt open urinary drainage (Foley catheter) using the double diaper technique for children who underwent hypospadias repair. We think that the reason why we had these unusual complications was probably due to the hole created through the first diaper for the distal end of the catheter. The opening was created in the part of diaper where the SAP were present and consecutively it was possible their leak and migration into the lumen of the catheter. SAP in touch with urine has reacted with their features: holding tightly the urine and increasing their volume. In this manner a catheter blockage was established.


The cases reported aim to warn all pediatric surgeons and pediatric urologists that perform day surgery hypospadias repair using the double diaper technique, to pay much attention to create the double diaper and to train nurses and the parents to do it, to avoid this unexpected complication.



  1. Belman AB. Hypospadias and other urethral abnormalities. In Kelalis PP, King LR, Belman AB, editor. Clinical pediatric urology. 3 rd ed. WB Saunders Co: Philadelphia; 1992. p. 619-63
  2. Buchholz F.L.: Absorbency and Superabsorbency In Buchholz F. L., Graham A. T. (Eds): Modern Superabsorbent Polymer Technology. New York; Wiley-VCH, 1997 pp 5- 42
  3. Snodgrass W. Tubularized, incised plate urethroplasty for distal hypospadias. J Urol. 1994; 151: 464-5
  4. Appignani A, Prestipino M, Bertozzi M, Nardi N, Falcone F. Doublecross flap protection: new technique for coverage of neourethra in hypospadias repair. J Urol. 2009; 182: 1521-7
  5. El-Sherbiny MT. Tubularised incised plate repair of distal hypospadias in toilet trained children: Should a stent be left? BJU Int 2003;92:1003-5
  6. Montagnino BA, Gonzales ET Jr, Roth DR. Open catheter drainage after urethral surgery J Urol. 1988 Nov;140(5 Pt 2):125