Risk Factors of Urethro-cutaneous Fistula Development in Hypospadias Surgery Faktor Risiko Fistel Urethokutan Pasca Operasi Hipospadia

Urethrocutaneous fistula development is the most common complication found hypospadias surgery. Several factors associated with the incidence of fistulas are the age at the time the surgery. The type of hypospadias, the degree of chordae, the operative technique applied and catheter type. This study aimed to determine the risk factors associated with the urethro-cutaneous fistula development in hypospadias surgery. The results showed that from 310 hypospadias patients undergoing urethroplasty, urethra cutaneous fistula development occurred among 105 patients (30.6%) with a mean age of surgery 10.89+6.27 years. Hypospadias type has a significant difference with the incidence of urethrocutaneous fistula development (p = 0.027). Age (p = 0.615), degree of chordae (P=0.805), operative technique (P=0.901) and catheter type (P=691) do not have a significant impact to urethro-cutaneous fistula development. It can be concluded that operative urethroplasty has a risk of urethra-cutaneous fistula that associated with hypospadias type.


INTRODUCTION
The term hypospadias comes from the Greek terms hypo and spadon which means below and gap respectively. Hypospadias is a congenital abnormality in the form of external urethral meatus which opens in the ventral aspect of the penis proximal to the tip of glans penis (1,2). This condition is often followed by the discovery of MUE in the ventral penis, chordae, and more dorsal skin folds (dorsal hood). Surgery is an option for hypospadias correction (3,4).
Urethro-cutaneous fistula development is the most common complication found after hypospadias repair, with incidence rates varying between 15% to 45% (5). Broadly, fistula is defined as a channel that connects two epithelial ducts. Urethrocutaneous fistula development can occur early after surgery or a period of time after surgery. Many factors contribute to the formation of fistulas in the body, such as hematoma, infection, overly tense approximation, and inadequate surgical wound management. Several literatures reported several conditions associated with urethrocutaneous fistula developments, including proximal hypospadias type, complicated surgical procedures, meatal stenosis, urethral strictures, urethral diverticulum, and infections (6).

METHOD
This study is an analytical observational study based on secondary data from patient medical records. The study was conducted at the Urology Clinic and Minimally Invasive Urology Installation, Dr. Soetomo General Academic Hospital, Surabaya, and has received approval from the ethical committee through certificate number 1504/KEPK/IX/2019. The data taken were data from primary hypospadias patients who had urethroplasty by two experienced urologists at Dr. Soetomo General Academic Hospital Surabaya in the period of June 2014 to June 2019. The criteria were patients aged 0-20 years with a hypospadias diagnosis and hypospadias repair in June 2014 -June 2019. Hypospadias patients who did not undergo surgery and patients with urethrocutaneous fistula caused by other abnormalities or multiple previous corrections were not included in this study. The variables recorded in this study were patient age, hypospadias type, chordae type, hypospadias repair technique, catheter type used, and onset time of fistula, whereas the dependent variable was fistula occurrence. The data were then presented descriptively, and statistical analysis was carried out using chi-square using SPSS version 21 for Windows.

RESULTS
Of the 310 patients who underwent urethroplasty, 105 patients (33.9%) suffered from fistula. The mean age of patients with fistula was higher (10.89+6.27) compared to those without the abnormality, albeit not significantly different. Urethrocutaneous fistula development occurred on the third week after surgery in 39 patients, fourth week after surgery in 34 patients, and 3 first week after surgery in 32 patients. The data show that most fistulas were found in the age range of 2-15 years old with proximal hypospadias type, medium chordae, and Tubularized Incised Plate (TIP) Urethroplasty operative technique. The proportion of the characteristics studied did not show differences in the pattern between patients with and without fistula. Of the four factors studied, only the hypospadias type had a correlation with the occurrence of fistula. number of study samples. As age increases, the child will have more frequent erections which could affect the healing process. In younger children, wound healing is faster than in older children (8). Several recent studies suggest that the hypospadias correction should done between 3 to 15 months of age; while in the European association of urology (EAU) guidelines, the correction is recommended at 6 to 18 months old (9).
This study found that there was a significant difference in the incidence of urethra-cutaneous fistula according to hypospadias type. Several studies explained that the highest incidence of urethra-cutaneous fistula was the proximal hypospadias type. Many factors cause urethrocutaneous fistula development complications in the proximal type, such as obstruction of urine flow distal to the neourethra, urethral diverticles, urinary extrusion, and local infection. In our study, we have found that proximal hypospadias has the highest incidence of urethro-cutaneous fistula. However, in this study distal hypospadias have the highest proportion of urethracutaneous fistula (50%). These results were in accordance with another study that focus on overall incidence of hypospadias in Indonesia which is the distal hypospadias suffer the most urethra-cutaneous fistula development (10). Elbakry in 2001 identified incidence of fistula was higher at the coronal sulcus which might influence by the fact that the coronary sulcus area has a hypo vascular transitional area of blood vessels between the skin and the glans penis. Hypospadias repair of the urethral plate in the glans area can cause disruption of blood supply in the coronary sulcus. in addition, an erection can cause a traction effect on the neourethra. It is explaining why neourethra healing in the corona area will more likely to be disrupted and why the urethro-cutaneous fistula mostly is distal hypospadias type (11).
In this study, it was found that the more severe the chordae, the higher the probability of the patient experiencing postoperative urethra-cutaneous fistula, although it was not statistically significant. A cordial correction has an important role in reducing the number of urethra-cutaneous fistula occurrences. Research by Braga et al., in 2007 identified five patients who experienced urethra-cutaneous fistula (14.2%), recurrent curvature in five patients (14.2%), urethral diverticles in two patients (5.7%), meatal stenosis in two patients (5.7%), and urethral stricture in one patient (2.8%). Inadequate excision of the chordae and impaired blood flow after chorda repair causes necrosis, which facilitates the development of a urethra-cutaneous fistula development (12).
The TIP technique had the highest incidence of urethracutaneous fistula (34.7%) but did not provide a statistically significant difference. Research in Indonesia by Fariz et al., in 2011 also found the same results. Decent surgical factors help reduce the incidence of urethra-cutaneous fistula.
Poor neourethra formation and vascularization, failed epithelialization of the neourethra, improper surgical procedures, necrosis in the flaps and grafts, improper use and thin epithelial tissue, improper and too tight suturing are the risk of incidence of urethro-cutaneous fistula (6).  (7). On the one hand, the use of a urethral catheter aims to prevent postoperative urethral edema that can block urine flow, reduce pain during urination, and as a splint that helps in healing the neourethra. On the other hand, the use of a catheter can cause an infection resulting from the migration of bacteria along the catheter. Furthermore, catheter balloons can also cause bladder spasms, and irritation due to the catheter components can delay wound healing (6,7).
The design of this study is a retrospective study that might generates information bias. Within this limitation, result of this study conclude that hypospadias type is a significant risk factor for urethra-cutaneous fistula at Dr. Soetomo General Academic Hospital.