Indocyanine Green (ICG)-Guided Onlay Preputial Island Flap Urethroplasty for the Single-Stage Repair of Hypospadias in Children: A Case Report

Abstract

First described by Duckett in 1981, and initially employed for the surgical correction of mid-penile hypospadias, the onlay preputial island flap urethroplasty has progressively gained increasing popularity, extending its indication to proximal forms. However, with the complexity of the penile anomaly, the rate of postoperative complications related to poor tissue perfusion (including skin and glans dehiscence, urethral stenoses, and fistulas) has also increased. Conventionally, the visual assessment of the onlay preputial island flap is the only option available to establish the appropriate tissue vascularization during surgery. To this end, we have first introduced the EleVision IR system (Medtronic Ltd., Hong Kong, China) to assess the vascular perfusion of the preputial island flap in a 13-month-old boy undergoing the onlay urethroplasty for the surgical correction of a mid-shaft hypospadias. This was possible 80 s after the intravenous injection of indocyanine green (ICG, 0.15 mg/kg, Diagnostic Green GmbH, Munich, Germany). ICG-based laser angiography helped define the proximal resection margin of the preputial flap, and proved to be safe, effective, and easy to employ. This innovative intraoperative imaging modality can be considered a useful adjunct for tissue perfusion evaluation and intraoperative decision-making during the onlay preputial island flap urethroplasty in children.

Keywords: children; fluorescence-guided surgery; hypospadias; indocyanine green; onlay preputial island flap; urethroplasty.

Figure 1

Aspect of the external genitalia of a 13-month-old boy referred to our tertiary referral hospital for mid-shaft hypospadias, who was scheduled for the onlay preputial island flap urethroplasty. (a) Preoperative aspect of the penis, characterized by a mid-shaft displacement of the external urinary meatus (*), mild ventral penile curvature, and a ventrally deficient hooded foreskin (→). (b) Immediate postoperative results, showing a straight penis with an apical neo-meatus. (c) Results at the 5-month follow-up, confirming the excellent esthetic and functional outcomes.

Figure 2

Main steps of the onlay preputial island flap urethroplasty. (a) Demarcation of the well-developed urethral plate. (b) Artificial erection test proving the lack of curvature after the release of the ventral skin chordees. (c) Transverse preputial island flap elevated on its pedicle (*). (d) Transverse preputial island flap (*) brought to the ventrum of the penis on its vascular pedicle sewn to the margins of the original urethral plate (→).

Figure 3

Main steps of the indocyanine green (ICG)-guided onlay preputial island flap urethroplasty in a 13-month-old boy referred to our tertiary referral hospital for a mid-shaft hypospadias. (a,b) Assessment of the vascular supply (*) of the transverse preputial island flap elevated on its pedicle, 80 s after the injection of 0.15 mg/kg of ICG (Diagnostic Green GmbH, Munich, Germany) and the incorporated the EleVision IR system (Medtronic Ltd.) on the surgical field. (c,d) Assessment of the vascular supply (*) of the transverse preputial island flap transposed ventrally and sewn to the margins of the urethral plate. (e,f) Assessment of the vascular supply (*) of the ventral part of the neo-urethra.