J Reconstr Microsurg 2006; 22(5): 353-356
DOI: 10.1055/s-2006-946713
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Copyright © 2006 by Thieme Medical Publishers, Inc., 333 Seventh Avenue, New York, NY 10001, USA.

Urethral Reconstruction for Hypospadias Using the Ulnar Forearm Flap

Norifumi Zen1 , Koichi Ueda1 , Sousuke Oba1
  • 1Department of Plastic and Reconstructive Surgery, Osaka Medical College, Japan
Further Information

Publication History

Accepted: March 1, 2006

Publication Date:
17 July 2006 (online)

Hypospadias is a congenital urethral abnormality associated with dysembryoplasia of the anterior urethra. The hereditary pattern is unknown, and the incidence is 1 in 300 male newborns.[1] When stenosis occurs after initial surgery with full-thickness skin graft for hypospadias, the disorder is likely to become intractable, and re-stenosis occurs, requiring multiple procedures in many cases. In such patients, local flaps cannot be used because of extensive scarring and it is necessary to cover the defective tissue with a distant flap. We performed reconstruction using an ulnar forearm flap in a patient who had undergone urethroplasty by full-thickness skin graft at the age of 3 years, and multiple surgical procedures due to repeated urethral stenosis. To our knowledge, there has been no other report of reconstruction using an ulnar forearm flap. By using this flap, the urethra could be reconstructed with hairless skin, and the outcome was satisfactory.

The patient was a 21-year-old male in whom hypospadias had been found at birth. The initial surgery was performed at the age of 3 years 5 months, and urethral reconstruction with full-thickness skin graft was performed in our department. Urethral obstruction occurred several times: the patient underwent closure of a fistula at 8 years of age, scar contracture release with a local flap for the narrowed urethra at 12 years, and urethral plasty with free skin graft at 16 years, but the problems were not resolved. The patient was repeatedly admitted for urethral stenosis, and antibiotic administration and urethral indwelling of a balloon were repeated.

At the time reported, the patient had severe feelings of urethral obstruction. On examination, urination was difficult, erection was accompanied by severe pain, and sexual intercourse was impossible. There was a sufficient amount of skin on the dorsal side of the penis, but the ventral side was in contact with cord-like tissue along the urethra, causing scar contracture, and the penis was bent toward the ventral side (Fig. [1]). The external ostium of the urethra was open at the tip of the penis, and no fistula was noted. On urethrography, severe stenosis was demonstrated in the urethra constructed by the skin graft, and post-stenotic expansion was recognized (Fig. [2]).

Figure 1 Preoperative appearance of the penis.

Figure 2 Preoperative urethrography noted severe stenosis in the urethra reconstructed with skin graft (stenosis is indicated by white arrows), and post-stenotic expansion.

Urethral reconstruction using a free ulnar forearm flap was performed under general anesthesia. The cord-like tissue on the ventral side of the penis, surgical scar tissue, and the skin graft that caused the stenosis were completely excised, and sufficient mobility of the penis was confirmed. Injury of the corpus cavernosum was avoided (Fig. [3]). During surgery, no sign of infection was noted in the urethra, but hair was noted on the inner urethral surface of the skin graft, which may have been related to the stenosis (Fig. [4]).

Figure 3 Stenotic urethra and scar tissue were removed and scar contracture was released. Urethra indicated by white arrow.

Figure 4 Inner surface of the urthral skin graft with hair seen on the inner surface.

Because the radial forearm skin was too hirsute the urethra was reconstructed with an ulnar forearm flap. We modified the cricket bat method[2] [3] and designed a flap measuring 3 × 12.5 cm. To prevent postoperative scar contracture, a 1-cm triangular flap[4] was arranged on both sides of the region corresponding to the urethra. The ulnar artery and the vena comitans were used for a vascular pedicle with a length of 9 cm. The urethra was prepared by winding the flap around a silicon balloon catheter (Figs. [5], [6]). A zigzag incision was made in the right inguinal region, and end-to-end anastomoses were made between the ulnar artery and right external pudendal artery, and between the vena comitans and the branch of the greater saphenous vein. The renewed distant end of the residual urethra and the urethra constructed with the flap were sutured, and the penile region of the flap was tubed to reconstruct the ventral side of the penis. The catheter was removed 18 days after surgery, and the patient started to walk to the toilet.

Figure 5 The ulnar forearm flap was designed on the left forearm.

Figure 6 Reconstructed urethra.

The postoperative course was smooth, and no fistula formation or difficulty in urination occurred. At 6 months after surgery, the patient had no problem in daily life, and was capable of urination in the standing position, erection, ejaculation, and sexual intercourse. The patient was sufficiently satisfied with the outcome (Figs. [7], [8]).

Figure 7 Postoperative appearance of the penis at postoperative 5 months.

Figure 8 Patient can urinate in the standing position.

Although the number of cases is very low, hypospadias may become intractable, and surgery may be repeated in patients who developed urethral stenosis after the initial surgery. In such patients, utilization of local tissues is difficult because of scar formation, but reconstruction with a free flap is one of the choices. In 1994, Chang and Huang[5] reported construction of the penis with a forearm flap. The urethra was reconstructed with the ulnar end of the flap distant from the radial artery, and the penis was reconstructed with the radial side. Biemer[6] [7] reported reconstruction of the urethra with skin on the radial side with rich blood flow, in which the procedure was modified to sandwich the urethra between two skin islands on the ulnar and radial sides to reconstruct the penis.

Semple et al.[2] reported the cricket bat phalloplasty suggesting reconstruction of the urethra region with a flap with good blood flow, in which the urethra was reconstructed with the hairless region immediately above the radial artery, and tubed. We also reported a similar method using skin immediately above the radial artery for urethral reconstruction.[4] [7]

Harashina et al.[8] reported that the free flaps utilized should be thin, durable, sufficiently large, hairless if possible, and contain a long, thick, and reliable neurovasuclar bundle. Forearm flaps are frequently used for reconstruction of the penis because harvesting is easy, blood circulation is stable and provides safety, flaps are thin and durable against double-folding, and vascularized bone can be obtained from the radius when support tissue is necessary for obtaining hardness.[9] [10] In another reported series forearm flaps were selected for 88 percent of 454 cases of reconstruction of the penis.[9]

In our case, hair in the urethral skin graft may have been one of the reasons for stenosis because of repeated infection. Since hair was present on the radial side of the forearm in this patient, the end of the ulnar forearm was selected for preparation of a flap immediately above the nutrient blood vessels for construction of the urethra with hairless skin. We did not choose to re-innervate the flap, because the defect was delimited on the ventral side of the penis. If the defect were larger, the flap could be re-innervated by the medial antebrachial nerve. To our knowledge, there has been no report of reconstruction of hypospadias with an ulnar forearm flap. The patient's postoperative course was uneventful, and urination in a standing position was achieved. This patient obtains erections, and is capable of masturbation, sexual intercourse, and sexual satisfaction. Cheng et al.[11] reported that of 136 patients who underwent reconstruction of the penis (reconstruction with a free forearm flap: 93), 111 patients could have sexual intercourse after surgery, 86 had sexual satisfaction, and eight patients reported subsequent pregnancy.

Construction with an ulnar forearm flap is a useful surgical procedure for hypospadias patients with a history of frequent urethral stenosis.

REFERENCES

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Norifumi ZenM.D. 

Department of Plastic and Reconstructive Surgery, Osaka Medical College

2-7, Daigakutyou, Takatukisi, Osaka, Japan

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